[gentoo-commits] proj/linux-patches:5.15 commit in: /

[Mike Pagano]

commit:     412bab2012d1b669b481463fd275bbb8bb6933fb
Author:     Mike Pagano <mpagano <AT> gentoo <DOT> org>
AuthorDate: Thu Nov  4 12:21:44 2021 +0000
Commit:     Mike Pagano <mpagano <AT> gentoo <DOT> org>
CommitDate: Thu Nov  4 12:21:44 2021 +0000
URL:        https://gitweb.gentoo.org/proj/linux-patches.git/commit/?id=412bab20

Add patch for the BMQ(BitMap Queue) Scheduler.

A new CPU scheduler developed from PDS(incld).
Inspired by the scheduler in zircon

Signed-off-by: Mike Pagano <mpagano <AT> gentoo.org>

 0000_README                                  |    8 +
 5020_BMQ-and-PDS-io-scheduler-v5.15-r0.patch | 9787 ++++++++++++++++++++++++++
 5021_BMQ-and-PDS-gentoo-defaults.patch       |   13 +
 3 files changed, 9808 insertions(+)

diff --git a/0000_README b/0000_README
index efde5c7..9bc9951 100644
--- a/0000_README
+++ b/0000_README
@@ -71,6 +71,14 @@ Patch:  4567_distro-Gentoo-Kconfig.patch
 From:   Tom Wijsman <TomWij@g.o>
 Desc:   Add Gentoo Linux support config settings and defaults.
 
+Patch:  5020_BMQ-and-PDS-io-scheduler-v5.15-r0.patch
+From:   https://gitlab.com/alfredchen/linux-prjc
+Desc:   BMQ(BitMap Queue) Scheduler. A new CPU scheduler developed from PDS(incld). Inspired by the scheduler in zircon.
+
+Patch:  5021_BMQ-and-PDS-gentoo-defaults.patch
+From:   https://gitweb.gentoo.org/proj/linux-patches.git/
+Desc:   Set defaults for BMQ. Add archs as people test, default to N
+
 Patch:  5010_enable-cpu-optimizations-universal.patch
 From:   https://github.com/graysky2/kernel_compiler_patch
 Desc:   Kernel >= 5.15 patch enables gcc = v11.1+ optimizations for additional CPUs.

diff --git a/5020_BMQ-and-PDS-io-scheduler-v5.15-r0.patch b/5020_BMQ-and-PDS-io-scheduler-v5.15-r0.patch
new file mode 100644
index 0000000..1d0c322
--- /dev/null
+++ b/5020_BMQ-and-PDS-io-scheduler-v5.15-r0.patch
@@ -0,0 +1,9787 @@
+diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
+index 43dc35fe5bc0..0873e92ca5d0 100644
+--- a/Documentation/admin-guide/kernel-parameters.txt
++++ b/Documentation/admin-guide/kernel-parameters.txt
+@@ -4985,6 +4985,12 @@
+ 	sa1100ir	[NET]
+ 			See drivers/net/irda/sa1100_ir.c.
+ 
++	sched_timeslice=
++			[KNL] Time slice in ms for Project C BMQ/PDS scheduler.
++			Format: integer 2, 4
++			Default: 4
++			See Documentation/scheduler/sched-BMQ.txt
++
+ 	sched_verbose	[KNL] Enables verbose scheduler debug messages.
+ 
+ 	schedstats=	[KNL,X86] Enable or disable scheduled statistics.
+diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
+index 426162009ce9..15ac2d7e47cd 100644
+--- a/Documentation/admin-guide/sysctl/kernel.rst
++++ b/Documentation/admin-guide/sysctl/kernel.rst
+@@ -1542,3 +1542,13 @@ is 10 seconds.
+ 
+ The softlockup threshold is (``2 * watchdog_thresh``). Setting this
+ tunable to zero will disable lockup detection altogether.
++
++yield_type:
++===========
++
++BMQ/PDS CPU scheduler only. This determines what type of yield calls
++to sched_yield will perform.
++
++  0 - No yield.
++  1 - Deboost and requeue task. (default)
++  2 - Set run queue skip task.
+diff --git a/Documentation/scheduler/sched-BMQ.txt b/Documentation/scheduler/sched-BMQ.txt
+new file mode 100644
+index 000000000000..05c84eec0f31
+--- /dev/null
++++ b/Documentation/scheduler/sched-BMQ.txt
+@@ -0,0 +1,110 @@
++                         BitMap queue CPU Scheduler
++                         --------------------------
++
++CONTENT
++========
++
++ Background
++ Design
++   Overview
++   Task policy
++   Priority management
++   BitMap Queue
++   CPU Assignment and Migration
++
++
++Background
++==========
++
++BitMap Queue CPU scheduler, referred to as BMQ from here on, is an evolution
++of previous Priority and Deadline based Skiplist multiple queue scheduler(PDS),
++and inspired by Zircon scheduler. The goal of it is to keep the scheduler code
++simple, while efficiency and scalable for interactive tasks, such as desktop,
++movie playback and gaming etc.
++
++Design
++======
++
++Overview
++--------
++
++BMQ use per CPU run queue design, each CPU(logical) has it's own run queue,
++each CPU is responsible for scheduling the tasks that are putting into it's
++run queue.
++
++The run queue is a set of priority queues. Note that these queues are fifo
++queue for non-rt tasks or priority queue for rt tasks in data structure. See
++BitMap Queue below for details. BMQ is optimized for non-rt tasks in the fact
++that most applications are non-rt tasks. No matter the queue is fifo or
++priority, In each queue is an ordered list of runnable tasks awaiting execution
++and the data structures are the same. When it is time for a new task to run,
++the scheduler simply looks the lowest numbered queueue that contains a task,
++and runs the first task from the head of that queue. And per CPU idle task is
++also in the run queue, so the scheduler can always find a task to run on from
++its run queue.
++
++Each task will assigned the same timeslice(default 4ms) when it is picked to
++start running. Task will be reinserted at the end of the appropriate priority
++queue when it uses its whole timeslice. When the scheduler selects a new task
++from the priority queue it sets the CPU's preemption timer for the remainder of
++the previous timeslice. When that timer fires the scheduler will stop execution
++on that task, select another task and start over again.
++
++If a task blocks waiting for a shared resource then it's taken out of its
++priority queue and is placed in a wait queue for the shared resource. When it
++is unblocked it will be reinserted in the appropriate priority queue of an
++eligible CPU.
++
++Task policy
++-----------
++
++BMQ supports DEADLINE, FIFO, RR, NORMAL, BATCH and IDLE task policy like the
++mainline CFS scheduler. But BMQ is heavy optimized for non-rt task, that's
++NORMAL/BATCH/IDLE policy tasks. Below is the implementation detail of each
++policy.
++
++DEADLINE
++	It is squashed as priority 0 FIFO task.
++
++FIFO/RR
++	All RT tasks share one single priority queue in BMQ run queue designed. The
++complexity of insert operation is O(n). BMQ is not designed for system runs
++with major rt policy tasks.
++
++NORMAL/BATCH/IDLE
++	BATCH and IDLE tasks are treated as the same policy. They compete CPU with
++NORMAL policy tasks, but they just don't boost. To control the priority of
++NORMAL/BATCH/IDLE tasks, simply use nice level.
++
++ISO
++	ISO policy is not supported in BMQ. Please use nice level -20 NORMAL policy
++task instead.
++
++Priority management
++-------------------
++
++RT tasks have priority from 0-99. For non-rt tasks, there are three different
++factors used to determine the effective priority of a task. The effective
++priority being what is used to determine which queue it will be in.
++
++The first factor is simply the task’s static priority. Which is assigned from
++task's nice level, within [-20, 19] in userland's point of view and [0, 39]
++internally.
++
++The second factor is the priority boost. This is a value bounded between
++[-MAX_PRIORITY_ADJ, MAX_PRIORITY_ADJ] used to offset the base priority, it is
++modified by the following cases:
++
++*When a thread has used up its entire timeslice, always deboost its boost by
++increasing by one.
++*When a thread gives up cpu control(voluntary or non-voluntary) to reschedule,
++and its switch-in time(time after last switch and run) below the thredhold
++based on its priority boost, will boost its boost by decreasing by one buti is
++capped at 0 (won’t go negative).
++
++The intent in this system is to ensure that interactive threads are serviced
++quickly. These are usually the threads that interact directly with the user
++and cause user-perceivable latency. These threads usually do little work and
++spend most of their time blocked awaiting another user event. So they get the
++priority boost from unblocking while background threads that do most of the
++processing receive the priority penalty for using their entire timeslice.
+diff --git a/fs/proc/base.c b/fs/proc/base.c
+index 533d5836eb9a..5756c51c9b58 100644
+--- a/fs/proc/base.c
++++ b/fs/proc/base.c
+@@ -477,7 +477,7 @@ static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
+ 		seq_puts(m, "0 0 0\n");
+ 	else
+ 		seq_printf(m, "%llu %llu %lu\n",
+-		   (unsigned long long)task->se.sum_exec_runtime,
++		   (unsigned long long)tsk_seruntime(task),
+ 		   (unsigned long long)task->sched_info.run_delay,
+ 		   task->sched_info.pcount);
+ 
+diff --git a/include/asm-generic/resource.h b/include/asm-generic/resource.h
+index 8874f681b056..59eb72bf7d5f 100644
+--- a/include/asm-generic/resource.h
++++ b/include/asm-generic/resource.h
+@@ -23,7 +23,7 @@
+ 	[RLIMIT_LOCKS]		= {  RLIM_INFINITY,  RLIM_INFINITY },	\
+ 	[RLIMIT_SIGPENDING]	= { 		0,	       0 },	\
+ 	[RLIMIT_MSGQUEUE]	= {   MQ_BYTES_MAX,   MQ_BYTES_MAX },	\
+-	[RLIMIT_NICE]		= { 0, 0 },				\
++	[RLIMIT_NICE]		= { 30, 30 },				\
+ 	[RLIMIT_RTPRIO]		= { 0, 0 },				\
+ 	[RLIMIT_RTTIME]		= {  RLIM_INFINITY,  RLIM_INFINITY },	\
+ }
+diff --git a/include/linux/sched.h b/include/linux/sched.h
+index c1a927ddec64..a7eb91d15442 100644
+--- a/include/linux/sched.h
++++ b/include/linux/sched.h
+@@ -748,12 +748,18 @@ struct task_struct {
+ 	unsigned int			ptrace;
+ 
+ #ifdef CONFIG_SMP
+-	int				on_cpu;
+ 	struct __call_single_node	wake_entry;
++#endif
++#if defined(CONFIG_SMP) || defined(CONFIG_SCHED_ALT)
++	int				on_cpu;
++#endif
++
++#ifdef CONFIG_SMP
+ #ifdef CONFIG_THREAD_INFO_IN_TASK
+ 	/* Current CPU: */
+ 	unsigned int			cpu;
+ #endif
++#ifndef CONFIG_SCHED_ALT
+ 	unsigned int			wakee_flips;
+ 	unsigned long			wakee_flip_decay_ts;
+ 	struct task_struct		*last_wakee;
+@@ -767,6 +773,7 @@ struct task_struct {
+ 	 */
+ 	int				recent_used_cpu;
+ 	int				wake_cpu;
++#endif /* !CONFIG_SCHED_ALT */
+ #endif
+ 	int				on_rq;
+ 
+@@ -775,6 +782,20 @@ struct task_struct {
+ 	int				normal_prio;
+ 	unsigned int			rt_priority;
+ 
++#ifdef CONFIG_SCHED_ALT
++	u64				last_ran;
++	s64				time_slice;
++	int				sq_idx;
++	struct list_head		sq_node;
++#ifdef CONFIG_SCHED_BMQ
++	int				boost_prio;
++#endif /* CONFIG_SCHED_BMQ */
++#ifdef CONFIG_SCHED_PDS
++	u64				deadline;
++#endif /* CONFIG_SCHED_PDS */
++	/* sched_clock time spent running */
++	u64				sched_time;
++#else /* !CONFIG_SCHED_ALT */
+ 	const struct sched_class	*sched_class;
+ 	struct sched_entity		se;
+ 	struct sched_rt_entity		rt;
+@@ -785,6 +806,7 @@ struct task_struct {
+ 	unsigned long			core_cookie;
+ 	unsigned int			core_occupation;
+ #endif
++#endif /* !CONFIG_SCHED_ALT */
+ 
+ #ifdef CONFIG_CGROUP_SCHED
+ 	struct task_group		*sched_task_group;
+@@ -1505,6 +1527,15 @@ struct task_struct {
+ 	 */
+ };
+ 
++#ifdef CONFIG_SCHED_ALT
++#define tsk_seruntime(t)		((t)->sched_time)
++/* replace the uncertian rt_timeout with 0UL */
++#define tsk_rttimeout(t)		(0UL)
++#else /* CFS */
++#define tsk_seruntime(t)	((t)->se.sum_exec_runtime)
++#define tsk_rttimeout(t)	((t)->rt.timeout)
++#endif /* !CONFIG_SCHED_ALT */
++
+ static inline struct pid *task_pid(struct task_struct *task)
+ {
+ 	return task->thread_pid;
+diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h
+index 1aff00b65f3c..216fdf2fe90c 100644
+--- a/include/linux/sched/deadline.h
++++ b/include/linux/sched/deadline.h
+@@ -1,5 +1,24 @@
+ /* SPDX-License-Identifier: GPL-2.0 */
+ 
++#ifdef CONFIG_SCHED_ALT
++
++static inline int dl_task(struct task_struct *p)
++{
++	return 0;
++}
++
++#ifdef CONFIG_SCHED_BMQ
++#define __tsk_deadline(p)	(0UL)
++#endif
++
++#ifdef CONFIG_SCHED_PDS
++#define __tsk_deadline(p)	((((u64) ((p)->prio))<<56) | (p)->deadline)
++#endif
++
++#else
++
++#define __tsk_deadline(p)	((p)->dl.deadline)
++
+ /*
+  * SCHED_DEADLINE tasks has negative priorities, reflecting
+  * the fact that any of them has higher prio than RT and
+@@ -19,6 +38,7 @@ static inline int dl_task(struct task_struct *p)
+ {
+ 	return dl_prio(p->prio);
+ }
++#endif /* CONFIG_SCHED_ALT */
+ 
+ static inline bool dl_time_before(u64 a, u64 b)
+ {
+diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
+index ab83d85e1183..6af9ae681116 100644
+--- a/include/linux/sched/prio.h
++++ b/include/linux/sched/prio.h
+@@ -18,6 +18,32 @@
+ #define MAX_PRIO		(MAX_RT_PRIO + NICE_WIDTH)
+ #define DEFAULT_PRIO		(MAX_RT_PRIO + NICE_WIDTH / 2)
+ 
++#ifdef CONFIG_SCHED_ALT
++
++/* Undefine MAX_PRIO and DEFAULT_PRIO */
++#undef MAX_PRIO
++#undef DEFAULT_PRIO
++
++/* +/- priority levels from the base priority */
++#ifdef CONFIG_SCHED_BMQ
++#define MAX_PRIORITY_ADJ	(7)
++
++#define MIN_NORMAL_PRIO		(MAX_RT_PRIO)
++#define MAX_PRIO		(MIN_NORMAL_PRIO + NICE_WIDTH)
++#define DEFAULT_PRIO		(MIN_NORMAL_PRIO + NICE_WIDTH / 2)
++#endif
++
++#ifdef CONFIG_SCHED_PDS
++#define MAX_PRIORITY_ADJ	(0)
++
++#define MIN_NORMAL_PRIO		(128)
++#define NORMAL_PRIO_NUM		(64)
++#define MAX_PRIO		(MIN_NORMAL_PRIO + NORMAL_PRIO_NUM)
++#define DEFAULT_PRIO		(MAX_PRIO - NICE_WIDTH / 2)
++#endif
++
++#endif /* CONFIG_SCHED_ALT */
++
+ /*
+  * Convert user-nice values [ -20 ... 0 ... 19 ]
+  * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
+diff --git a/include/linux/sched/rt.h b/include/linux/sched/rt.h
+index e5af028c08b4..0a7565d0d3cf 100644
+--- a/include/linux/sched/rt.h
++++ b/include/linux/sched/rt.h
+@@ -24,8 +24,10 @@ static inline bool task_is_realtime(struct task_struct *tsk)
+ 
+ 	if (policy == SCHED_FIFO || policy == SCHED_RR)
+ 		return true;
++#ifndef CONFIG_SCHED_ALT
+ 	if (policy == SCHED_DEADLINE)
+ 		return true;
++#endif
+ 	return false;
+ }
+ 
+diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
+index 8f0f778b7c91..991f2280475b 100644
+--- a/include/linux/sched/topology.h
++++ b/include/linux/sched/topology.h
+@@ -225,7 +225,8 @@ static inline bool cpus_share_cache(int this_cpu, int that_cpu)
+ 
+ #endif	/* !CONFIG_SMP */
+ 
+-#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
++#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) && \
++	!defined(CONFIG_SCHED_ALT)
+ extern void rebuild_sched_domains_energy(void);
+ #else
+ static inline void rebuild_sched_domains_energy(void)
+diff --git a/init/Kconfig b/init/Kconfig
+index 11f8a845f259..c8e82fcafb9e 100644
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -814,9 +814,39 @@ config GENERIC_SCHED_CLOCK
+ 
+ menu "Scheduler features"
+ 
++menuconfig SCHED_ALT
++	bool "Alternative CPU Schedulers"
++	default y
++	help
++	  This feature enable alternative CPU scheduler"
++
++if SCHED_ALT
++
++choice
++	prompt "Alternative CPU Scheduler"
++	default SCHED_BMQ
++
++config SCHED_BMQ
++	bool "BMQ CPU scheduler"
++	help
++	  The BitMap Queue CPU scheduler for excellent interactivity and
++	  responsiveness on the desktop and solid scalability on normal
++	  hardware and commodity servers.
++
++config SCHED_PDS
++	bool "PDS CPU scheduler"
++	help
++	  The Priority and Deadline based Skip list multiple queue CPU
++	  Scheduler.
++
++endchoice
++
++endif
++
+ config UCLAMP_TASK
+ 	bool "Enable utilization clamping for RT/FAIR tasks"
+ 	depends on CPU_FREQ_GOV_SCHEDUTIL
++	depends on !SCHED_ALT
+ 	help
+ 	  This feature enables the scheduler to track the clamped utilization
+ 	  of each CPU based on RUNNABLE tasks scheduled on that CPU.
+@@ -902,6 +932,7 @@ config NUMA_BALANCING
+ 	depends on ARCH_SUPPORTS_NUMA_BALANCING
+ 	depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
+ 	depends on SMP && NUMA && MIGRATION
++	depends on !SCHED_ALT
+ 	help
+ 	  This option adds support for automatic NUMA aware memory/task placement.
+ 	  The mechanism is quite primitive and is based on migrating memory when
+@@ -994,6 +1025,7 @@ config FAIR_GROUP_SCHED
+ 	depends on CGROUP_SCHED
+ 	default CGROUP_SCHED
+ 
++if !SCHED_ALT
+ config CFS_BANDWIDTH
+ 	bool "CPU bandwidth provisioning for FAIR_GROUP_SCHED"
+ 	depends on FAIR_GROUP_SCHED
+@@ -1016,6 +1048,7 @@ config RT_GROUP_SCHED
+ 	  realtime bandwidth for them.
+ 	  See Documentation/scheduler/sched-rt-group.rst for more information.
+ 
++endif #!SCHED_ALT
+ endif #CGROUP_SCHED
+ 
+ config UCLAMP_TASK_GROUP
+@@ -1259,6 +1292,7 @@ config CHECKPOINT_RESTORE
+ 
+ config SCHED_AUTOGROUP
+ 	bool "Automatic process group scheduling"
++	depends on !SCHED_ALT
+ 	select CGROUPS
+ 	select CGROUP_SCHED
+ 	select FAIR_GROUP_SCHED
+diff --git a/init/init_task.c b/init/init_task.c
+index 2d024066e27b..49f706df0904 100644
+--- a/init/init_task.c
++++ b/init/init_task.c
+@@ -75,9 +75,15 @@ struct task_struct init_task
+ 	.stack		= init_stack,
+ 	.usage		= REFCOUNT_INIT(2),
+ 	.flags		= PF_KTHREAD,
++#ifdef CONFIG_SCHED_ALT
++	.prio		= DEFAULT_PRIO + MAX_PRIORITY_ADJ,
++	.static_prio	= DEFAULT_PRIO,
++	.normal_prio	= DEFAULT_PRIO + MAX_PRIORITY_ADJ,
++#else
+ 	.prio		= MAX_PRIO - 20,
+ 	.static_prio	= MAX_PRIO - 20,
+ 	.normal_prio	= MAX_PRIO - 20,
++#endif
+ 	.policy		= SCHED_NORMAL,
+ 	.cpus_ptr	= &init_task.cpus_mask,
+ 	.user_cpus_ptr	= NULL,
+@@ -88,6 +94,17 @@ struct task_struct init_task
+ 	.restart_block	= {
+ 		.fn = do_no_restart_syscall,
+ 	},
++#ifdef CONFIG_SCHED_ALT
++	.sq_node	= LIST_HEAD_INIT(init_task.sq_node),
++#ifdef CONFIG_SCHED_BMQ
++	.boost_prio	= 0,
++	.sq_idx		= 15,
++#endif
++#ifdef CONFIG_SCHED_PDS
++	.deadline	= 0,
++#endif
++	.time_slice	= HZ,
++#else
+ 	.se		= {
+ 		.group_node 	= LIST_HEAD_INIT(init_task.se.group_node),
+ 	},
+@@ -95,6 +112,7 @@ struct task_struct init_task
+ 		.run_list	= LIST_HEAD_INIT(init_task.rt.run_list),
+ 		.time_slice	= RR_TIMESLICE,
+ 	},
++#endif
+ 	.tasks		= LIST_HEAD_INIT(init_task.tasks),
+ #ifdef CONFIG_SMP
+ 	.pushable_tasks	= PLIST_NODE_INIT(init_task.pushable_tasks, MAX_PRIO),
+diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt
+index 5876e30c5740..7594d0a31869 100644
+--- a/kernel/Kconfig.preempt
++++ b/kernel/Kconfig.preempt
+@@ -102,7 +102,7 @@ config PREEMPT_DYNAMIC
+ 
+ config SCHED_CORE
+ 	bool "Core Scheduling for SMT"
+-	depends on SCHED_SMT
++	depends on SCHED_SMT && !SCHED_ALT
+ 	help
+ 	  This option permits Core Scheduling, a means of coordinated task
+ 	  selection across SMT siblings. When enabled -- see
+diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
+index 2a9695ccb65f..292112c267b8 100644
+--- a/kernel/cgroup/cpuset.c
++++ b/kernel/cgroup/cpuset.c
+@@ -664,7 +664,7 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
+ 	return ret;
+ }
+ 
+-#ifdef CONFIG_SMP
++#if defined(CONFIG_SMP) && !defined(CONFIG_SCHED_ALT)
+ /*
+  * Helper routine for generate_sched_domains().
+  * Do cpusets a, b have overlapping effective cpus_allowed masks?
+@@ -1060,7 +1060,7 @@ static void rebuild_sched_domains_locked(void)
+ 	/* Have scheduler rebuild the domains */
+ 	partition_and_rebuild_sched_domains(ndoms, doms, attr);
+ }
+-#else /* !CONFIG_SMP */
++#else /* !CONFIG_SMP || CONFIG_SCHED_ALT */
+ static void rebuild_sched_domains_locked(void)
+ {
+ }
+diff --git a/kernel/delayacct.c b/kernel/delayacct.c
+index 51530d5b15a8..e542d71bb94b 100644
+--- a/kernel/delayacct.c
++++ b/kernel/delayacct.c
+@@ -139,7 +139,7 @@ int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
+ 	 */
+ 	t1 = tsk->sched_info.pcount;
+ 	t2 = tsk->sched_info.run_delay;
+-	t3 = tsk->se.sum_exec_runtime;
++	t3 = tsk_seruntime(tsk);
+ 
+ 	d->cpu_count += t1;
+ 
+diff --git a/kernel/exit.c b/kernel/exit.c
+index 91a43e57a32e..4b157befc10c 100644
+--- a/kernel/exit.c
++++ b/kernel/exit.c
+@@ -122,7 +122,7 @@ static void __exit_signal(struct task_struct *tsk)
+ 			sig->curr_target = next_thread(tsk);
+ 	}
+ 
+-	add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
++	add_device_randomness((const void*) &tsk_seruntime(tsk),
+ 			      sizeof(unsigned long long));
+ 
+ 	/*
+@@ -143,7 +143,7 @@ static void __exit_signal(struct task_struct *tsk)
+ 	sig->inblock += task_io_get_inblock(tsk);
+ 	sig->oublock += task_io_get_oublock(tsk);
+ 	task_io_accounting_add(&sig->ioac, &tsk->ioac);
+-	sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
++	sig->sum_sched_runtime += tsk_seruntime(tsk);
+ 	sig->nr_threads--;
+ 	__unhash_process(tsk, group_dead);
+ 	write_sequnlock(&sig->stats_lock);
+diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
+index 291b857a6e20..f3480cdb7497 100644
+--- a/kernel/livepatch/transition.c
++++ b/kernel/livepatch/transition.c
+@@ -307,7 +307,11 @@ static bool klp_try_switch_task(struct task_struct *task)
+ 	 */
+ 	rq = task_rq_lock(task, &flags);
+ 
++#ifdef	CONFIG_SCHED_ALT
++	if (task_running(task) && task != current) {
++#else
+ 	if (task_running(rq, task) && task != current) {
++#endif
+ 		snprintf(err_buf, STACK_ERR_BUF_SIZE,
+ 			 "%s: %s:%d is running\n", __func__, task->comm,
+ 			 task->pid);
+diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
+index 6bb116c559b4..d4c8168a8270 100644
+--- a/kernel/locking/rtmutex.c
++++ b/kernel/locking/rtmutex.c
+@@ -298,21 +298,25 @@ static __always_inline void
+ waiter_update_prio(struct rt_mutex_waiter *waiter, struct task_struct *task)
+ {
+ 	waiter->prio = __waiter_prio(task);
+-	waiter->deadline = task->dl.deadline;
++	waiter->deadline = __tsk_deadline(task);
+ }
+ 
+ /*
+  * Only use with rt_mutex_waiter_{less,equal}()
+  */
+ #define task_to_waiter(p)	\
+-	&(struct rt_mutex_waiter){ .prio = __waiter_prio(p), .deadline = (p)->dl.deadline }
++	&(struct rt_mutex_waiter){ .prio = __waiter_prio(p), .deadline = __tsk_deadline(p) }
+ 
+ static __always_inline int rt_mutex_waiter_less(struct rt_mutex_waiter *left,
+ 						struct rt_mutex_waiter *right)
+ {
++#ifdef CONFIG_SCHED_PDS
++	return (left->deadline < right->deadline);
++#else
+ 	if (left->prio < right->prio)
+ 		return 1;
+ 
++#ifndef CONFIG_SCHED_BMQ
+ 	/*
+ 	 * If both waiters have dl_prio(), we check the deadlines of the
+ 	 * associated tasks.
+@@ -321,16 +325,22 @@ static __always_inline int rt_mutex_waiter_less(struct rt_mutex_waiter *left,
+ 	 */
+ 	if (dl_prio(left->prio))
+ 		return dl_time_before(left->deadline, right->deadline);
++#endif
+ 
+ 	return 0;
++#endif
+ }
+ 
+ static __always_inline int rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
+ 						 struct rt_mutex_waiter *right)
+ {
++#ifdef CONFIG_SCHED_PDS
++	return (left->deadline == right->deadline);
++#else
+ 	if (left->prio != right->prio)
+ 		return 0;
+ 
++#ifndef CONFIG_SCHED_BMQ
+ 	/*
+ 	 * If both waiters have dl_prio(), we check the deadlines of the
+ 	 * associated tasks.
+@@ -339,8 +349,10 @@ static __always_inline int rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
+ 	 */
+ 	if (dl_prio(left->prio))
+ 		return left->deadline == right->deadline;
++#endif
+ 
+ 	return 1;
++#endif
+ }
+ 
+ static inline bool rt_mutex_steal(struct rt_mutex_waiter *waiter,
+diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
+index 978fcfca5871..0425ee149b4d 100644
+--- a/kernel/sched/Makefile
++++ b/kernel/sched/Makefile
+@@ -22,14 +22,21 @@ ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
+ CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer
+ endif
+ 
+-obj-y += core.o loadavg.o clock.o cputime.o
+-obj-y += idle.o fair.o rt.o deadline.o
+-obj-y += wait.o wait_bit.o swait.o completion.o
+-
+-obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o topology.o stop_task.o pelt.o
++ifdef CONFIG_SCHED_ALT
++obj-y += alt_core.o
++obj-$(CONFIG_SCHED_DEBUG) += alt_debug.o
++else
++obj-y += core.o
++obj-y += fair.o rt.o deadline.o
++obj-$(CONFIG_SMP) += cpudeadline.o stop_task.o
+ obj-$(CONFIG_SCHED_AUTOGROUP) += autogroup.o
+-obj-$(CONFIG_SCHEDSTATS) += stats.o
++endif
+ obj-$(CONFIG_SCHED_DEBUG) += debug.o
++obj-y += loadavg.o clock.o cputime.o
++obj-y += idle.o
++obj-y += wait.o wait_bit.o swait.o completion.o
++obj-$(CONFIG_SMP) += cpupri.o pelt.o topology.o
++obj-$(CONFIG_SCHEDSTATS) += stats.o
+ obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o
+ obj-$(CONFIG_CPU_FREQ) += cpufreq.o
+ obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o
+diff --git a/kernel/sched/alt_core.c b/kernel/sched/alt_core.c
+new file mode 100644
+index 000000000000..9576c57f82da
+--- /dev/null
++++ b/kernel/sched/alt_core.c
+@@ -0,0 +1,7626 @@
++/*
++ *  kernel/sched/alt_core.c
++ *
++ *  Core alternative kernel scheduler code and related syscalls
++ *
++ *  Copyright (C) 1991-2002  Linus Torvalds
++ *
++ *  2009-08-13	Brainfuck deadline scheduling policy by Con Kolivas deletes
++ *		a whole lot of those previous things.
++ *  2017-09-06	Priority and Deadline based Skip list multiple queue kernel
++ *		scheduler by Alfred Chen.
++ *  2019-02-20	BMQ(BitMap Queue) kernel scheduler by Alfred Chen.
++ */
++#define CREATE_TRACE_POINTS
++#include <trace/events/sched.h>
++#undef CREATE_TRACE_POINTS
++
++#include "sched.h"
++
++#include <linux/sched/rt.h>
++
++#include <linux/context_tracking.h>
++#include <linux/compat.h>
++#include <linux/blkdev.h>
++#include <linux/delayacct.h>
++#include <linux/freezer.h>
++#include <linux/init_task.h>
++#include <linux/kprobes.h>
++#include <linux/mmu_context.h>
++#include <linux/nmi.h>
++#include <linux/profile.h>
++#include <linux/rcupdate_wait.h>
++#include <linux/security.h>
++#include <linux/syscalls.h>
++#include <linux/wait_bit.h>
++
++#include <linux/kcov.h>
++#include <linux/scs.h>
++
++#include <asm/switch_to.h>
++
++#include "../workqueue_internal.h"
++#include "../../fs/io-wq.h"
++#include "../smpboot.h"
++
++#include "pelt.h"
++#include "smp.h"
++
++/*
++ * Export tracepoints that act as a bare tracehook (ie: have no trace event
++ * associated with them) to allow external modules to probe them.
++ */
++EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_irq_tp);
++
++#ifdef CONFIG_SCHED_DEBUG
++#define sched_feat(x)	(1)
++/*
++ * Print a warning if need_resched is set for the given duration (if
++ * LATENCY_WARN is enabled).
++ *
++ * If sysctl_resched_latency_warn_once is set, only one warning will be shown
++ * per boot.
++ */
++__read_mostly int sysctl_resched_latency_warn_ms = 100;
++__read_mostly int sysctl_resched_latency_warn_once = 1;
++#else
++#define sched_feat(x)	(0)
++#endif /* CONFIG_SCHED_DEBUG */
++
++#define ALT_SCHED_VERSION "v5.15-r0"
++
++/* rt_prio(prio) defined in include/linux/sched/rt.h */
++#define rt_task(p)		rt_prio((p)->prio)
++#define rt_policy(policy)	((policy) == SCHED_FIFO || (policy) == SCHED_RR)
++#define task_has_rt_policy(p)	(rt_policy((p)->policy))
++
++#define STOP_PRIO		(MAX_RT_PRIO - 1)
++
++/* Default time slice is 4 in ms, can be set via kernel parameter "sched_timeslice" */
++u64 sched_timeslice_ns __read_mostly = (4 << 20);
++
++static inline void requeue_task(struct task_struct *p, struct rq *rq);
++
++#ifdef CONFIG_SCHED_BMQ
++#include "bmq.h"
++#endif
++#ifdef CONFIG_SCHED_PDS
++#include "pds.h"
++#endif
++
++static int __init sched_timeslice(char *str)
++{
++	int timeslice_ms;
++
++	get_option(&str, &timeslice_ms);
++	if (2 != timeslice_ms)
++		timeslice_ms = 4;
++	sched_timeslice_ns = timeslice_ms << 20;
++	sched_timeslice_imp(timeslice_ms);
++
++	return 0;
++}
++early_param("sched_timeslice", sched_timeslice);
++
++/* Reschedule if less than this many μs left */
++#define RESCHED_NS		(100 << 10)
++
++/**
++ * sched_yield_type - Choose what sort of yield sched_yield will perform.
++ * 0: No yield.
++ * 1: Deboost and requeue task. (default)
++ * 2: Set rq skip task.
++ */
++int sched_yield_type __read_mostly = 1;
++
++#ifdef CONFIG_SMP
++static cpumask_t sched_rq_pending_mask ____cacheline_aligned_in_smp;
++
++DEFINE_PER_CPU(cpumask_t [NR_CPU_AFFINITY_LEVELS], sched_cpu_topo_masks);
++DEFINE_PER_CPU(cpumask_t *, sched_cpu_llc_mask);
++DEFINE_PER_CPU(cpumask_t *, sched_cpu_topo_end_mask);
++
++#ifdef CONFIG_SCHED_SMT
++DEFINE_STATIC_KEY_FALSE(sched_smt_present);
++EXPORT_SYMBOL_GPL(sched_smt_present);
++#endif
++
++/*
++ * Keep a unique ID per domain (we use the first CPUs number in the cpumask of
++ * the domain), this allows us to quickly tell if two cpus are in the same cache
++ * domain, see cpus_share_cache().
++ */
++DEFINE_PER_CPU(int, sd_llc_id);
++#endif /* CONFIG_SMP */
++
++static DEFINE_MUTEX(sched_hotcpu_mutex);
++
++DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
++
++#ifndef prepare_arch_switch
++# define prepare_arch_switch(next)	do { } while (0)
++#endif
++#ifndef finish_arch_post_lock_switch
++# define finish_arch_post_lock_switch()	do { } while (0)
++#endif
++
++#ifdef CONFIG_SCHED_SMT
++static cpumask_t sched_sg_idle_mask ____cacheline_aligned_in_smp;
++#endif
++static cpumask_t sched_rq_watermark[SCHED_BITS] ____cacheline_aligned_in_smp;
++
++/* sched_queue related functions */
++static inline void sched_queue_init(struct sched_queue *q)
++{
++	int i;
++
++	bitmap_zero(q->bitmap, SCHED_BITS);
++	for(i = 0; i < SCHED_BITS; i++)
++		INIT_LIST_HEAD(&q->heads[i]);
++}
++
++/*
++ * Init idle task and put into queue structure of rq
++ * IMPORTANT: may be called multiple times for a single cpu
++ */
++static inline void sched_queue_init_idle(struct sched_queue *q,
++					 struct task_struct *idle)
++{
++	idle->sq_idx = IDLE_TASK_SCHED_PRIO;
++	INIT_LIST_HEAD(&q->heads[idle->sq_idx]);
++	list_add(&idle->sq_node, &q->heads[idle->sq_idx]);
++}
++
++/* water mark related functions */
++static inline void update_sched_rq_watermark(struct rq *rq)
++{
++	unsigned long watermark = find_first_bit(rq->queue.bitmap, SCHED_QUEUE_BITS);
++	unsigned long last_wm = rq->watermark;
++	unsigned long i;
++	int cpu;
++
++	if (watermark == last_wm)
++		return;
++
++	rq->watermark = watermark;
++	cpu = cpu_of(rq);
++	if (watermark < last_wm) {
++		for (i = last_wm; i > watermark; i--)
++			cpumask_clear_cpu(cpu, sched_rq_watermark + SCHED_BITS - 1 - i);
++#ifdef CONFIG_SCHED_SMT
++		if (static_branch_likely(&sched_smt_present) &&
++		    IDLE_TASK_SCHED_PRIO == last_wm)
++			cpumask_andnot(&sched_sg_idle_mask,
++				       &sched_sg_idle_mask, cpu_smt_mask(cpu));
++#endif
++		return;
++	}
++	/* last_wm < watermark */
++	for (i = watermark; i > last_wm; i--)
++		cpumask_set_cpu(cpu, sched_rq_watermark + SCHED_BITS - 1 - i);
++#ifdef CONFIG_SCHED_SMT
++	if (static_branch_likely(&sched_smt_present) &&
++	    IDLE_TASK_SCHED_PRIO == watermark) {
++		cpumask_t tmp;
++
++		cpumask_and(&tmp, cpu_smt_mask(cpu), sched_rq_watermark);
++		if (cpumask_equal(&tmp, cpu_smt_mask(cpu)))
++			cpumask_or(&sched_sg_idle_mask,
++				   &sched_sg_idle_mask, cpu_smt_mask(cpu));
++	}
++#endif
++}
++
++/*
++ * This routine assume that the idle task always in queue
++ */
++static inline struct task_struct *sched_rq_first_task(struct rq *rq)
++{
++	unsigned long idx = find_first_bit(rq->queue.bitmap, SCHED_QUEUE_BITS);
++	const struct list_head *head = &rq->queue.heads[sched_prio2idx(idx, rq)];
++
++	return list_first_entry(head, struct task_struct, sq_node);
++}
++
++static inline struct task_struct *
++sched_rq_next_task(struct task_struct *p, struct rq *rq)
++{
++	unsigned long idx = p->sq_idx;
++	struct list_head *head = &rq->queue.heads[idx];
++
++	if (list_is_last(&p->sq_node, head)) {
++		idx = find_next_bit(rq->queue.bitmap, SCHED_QUEUE_BITS,
++				    sched_idx2prio(idx, rq) + 1);
++		head = &rq->queue.heads[sched_prio2idx(idx, rq)];
++
++		return list_first_entry(head, struct task_struct, sq_node);
++	}
++
++	return list_next_entry(p, sq_node);
++}
++
++static inline struct task_struct *rq_runnable_task(struct rq *rq)
++{
++	struct task_struct *next = sched_rq_first_task(rq);
++
++	if (unlikely(next == rq->skip))
++		next = sched_rq_next_task(next, rq);
++
++	return next;
++}
++
++/*
++ * Serialization rules:
++ *
++ * Lock order:
++ *
++ *   p->pi_lock
++ *     rq->lock
++ *       hrtimer_cpu_base->lock (hrtimer_start() for bandwidth controls)
++ *
++ *  rq1->lock
++ *    rq2->lock  where: rq1 < rq2
++ *
++ * Regular state:
++ *
++ * Normal scheduling state is serialized by rq->lock. __schedule() takes the
++ * local CPU's rq->lock, it optionally removes the task from the runqueue and
++ * always looks at the local rq data structures to find the most eligible task
++ * to run next.
++ *
++ * Task enqueue is also under rq->lock, possibly taken from another CPU.
++ * Wakeups from another LLC domain might use an IPI to transfer the enqueue to
++ * the local CPU to avoid bouncing the runqueue state around [ see
++ * ttwu_queue_wakelist() ]
++ *
++ * Task wakeup, specifically wakeups that involve migration, are horribly
++ * complicated to avoid having to take two rq->locks.
++ *
++ * Special state:
++ *
++ * System-calls and anything external will use task_rq_lock() which acquires
++ * both p->pi_lock and rq->lock. As a consequence the state they change is
++ * stable while holding either lock:
++ *
++ *  - sched_setaffinity()/
++ *    set_cpus_allowed_ptr():	p->cpus_ptr, p->nr_cpus_allowed
++ *  - set_user_nice():		p->se.load, p->*prio
++ *  - __sched_setscheduler():	p->sched_class, p->policy, p->*prio,
++ *				p->se.load, p->rt_priority,
++ *				p->dl.dl_{runtime, deadline, period, flags, bw, density}
++ *  - sched_setnuma():		p->numa_preferred_nid
++ *  - sched_move_task()/
++ *    cpu_cgroup_fork():	p->sched_task_group
++ *  - uclamp_update_active()	p->uclamp*
++ *
++ * p->state <- TASK_*:
++ *
++ *   is changed locklessly using set_current_state(), __set_current_state() or
++ *   set_special_state(), see their respective comments, or by
++ *   try_to_wake_up(). This latter uses p->pi_lock to serialize against
++ *   concurrent self.
++ *
++ * p->on_rq <- { 0, 1 = TASK_ON_RQ_QUEUED, 2 = TASK_ON_RQ_MIGRATING }:
++ *
++ *   is set by activate_task() and cleared by deactivate_task(), under
++ *   rq->lock. Non-zero indicates the task is runnable, the special
++ *   ON_RQ_MIGRATING state is used for migration without holding both
++ *   rq->locks. It indicates task_cpu() is not stable, see task_rq_lock().
++ *
++ * p->on_cpu <- { 0, 1 }:
++ *
++ *   is set by prepare_task() and cleared by finish_task() such that it will be
++ *   set before p is scheduled-in and cleared after p is scheduled-out, both
++ *   under rq->lock. Non-zero indicates the task is running on its CPU.
++ *
++ *   [ The astute reader will observe that it is possible for two tasks on one
++ *     CPU to have ->on_cpu = 1 at the same time. ]
++ *
++ * task_cpu(p): is changed by set_task_cpu(), the rules are:
++ *
++ *  - Don't call set_task_cpu() on a blocked task:
++ *
++ *    We don't care what CPU we're not running on, this simplifies hotplug,
++ *    the CPU assignment of blocked tasks isn't required to be valid.
++ *
++ *  - for try_to_wake_up(), called under p->pi_lock:
++ *
++ *    This allows try_to_wake_up() to only take one rq->lock, see its comment.
++ *
++ *  - for migration called under rq->lock:
++ *    [ see task_on_rq_migrating() in task_rq_lock() ]
++ *
++ *    o move_queued_task()
++ *    o detach_task()
++ *
++ *  - for migration called under double_rq_lock():
++ *
++ *    o __migrate_swap_task()
++ *    o push_rt_task() / pull_rt_task()
++ *    o push_dl_task() / pull_dl_task()
++ *    o dl_task_offline_migration()
++ *
++ */
++
++/*
++ * Context: p->pi_lock
++ */
++static inline struct rq
++*__task_access_lock(struct task_struct *p, raw_spinlock_t **plock)
++{
++	struct rq *rq;
++	for (;;) {
++		rq = task_rq(p);
++		if (p->on_cpu || task_on_rq_queued(p)) {
++			raw_spin_lock(&rq->lock);
++			if (likely((p->on_cpu || task_on_rq_queued(p))
++				   && rq == task_rq(p))) {
++				*plock = &rq->lock;
++				return rq;
++			}
++			raw_spin_unlock(&rq->lock);
++		} else if (task_on_rq_migrating(p)) {
++			do {
++				cpu_relax();
++			} while (unlikely(task_on_rq_migrating(p)));
++		} else {
++			*plock = NULL;
++			return rq;
++		}
++	}
++}
++
++static inline void
++__task_access_unlock(struct task_struct *p, raw_spinlock_t *lock)
++{
++	if (NULL != lock)
++		raw_spin_unlock(lock);
++}
++
++static inline struct rq
++*task_access_lock_irqsave(struct task_struct *p, raw_spinlock_t **plock,
++			  unsigned long *flags)
++{
++	struct rq *rq;
++	for (;;) {
++		rq = task_rq(p);
++		if (p->on_cpu || task_on_rq_queued(p)) {
++			raw_spin_lock_irqsave(&rq->lock, *flags);
++			if (likely((p->on_cpu || task_on_rq_queued(p))
++				   && rq == task_rq(p))) {
++				*plock = &rq->lock;
++				return rq;
++			}
++			raw_spin_unlock_irqrestore(&rq->lock, *flags);
++		} else if (task_on_rq_migrating(p)) {
++			do {
++				cpu_relax();
++			} while (unlikely(task_on_rq_migrating(p)));
++		} else {
++			raw_spin_lock_irqsave(&p->pi_lock, *flags);
++			if (likely(!p->on_cpu && !p->on_rq &&
++				   rq == task_rq(p))) {
++				*plock = &p->pi_lock;
++				return rq;
++			}
++			raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
++		}
++	}
++}
++
++static inline void
++task_access_unlock_irqrestore(struct task_struct *p, raw_spinlock_t *lock,
++			      unsigned long *flags)
++{
++	raw_spin_unlock_irqrestore(lock, *flags);
++}
++
++/*
++ * __task_rq_lock - lock the rq @p resides on.
++ */
++struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
++	__acquires(rq->lock)
++{
++	struct rq *rq;
++
++	lockdep_assert_held(&p->pi_lock);
++
++	for (;;) {
++		rq = task_rq(p);
++		raw_spin_lock(&rq->lock);
++		if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
++			return rq;
++		raw_spin_unlock(&rq->lock);
++
++		while (unlikely(task_on_rq_migrating(p)))
++			cpu_relax();
++	}
++}
++
++/*
++ * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
++ */
++struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
++	__acquires(p->pi_lock)
++	__acquires(rq->lock)
++{
++	struct rq *rq;
++
++	for (;;) {
++		raw_spin_lock_irqsave(&p->pi_lock, rf->flags);
++		rq = task_rq(p);
++		raw_spin_lock(&rq->lock);
++		/*
++		 *	move_queued_task()		task_rq_lock()
++		 *
++		 *	ACQUIRE (rq->lock)
++		 *	[S] ->on_rq = MIGRATING		[L] rq = task_rq()
++		 *	WMB (__set_task_cpu())		ACQUIRE (rq->lock);
++		 *	[S] ->cpu = new_cpu		[L] task_rq()
++		 *					[L] ->on_rq
++		 *	RELEASE (rq->lock)
++		 *
++		 * If we observe the old CPU in task_rq_lock(), the acquire of
++		 * the old rq->lock will fully serialize against the stores.
++		 *
++		 * If we observe the new CPU in task_rq_lock(), the address
++		 * dependency headed by '[L] rq = task_rq()' and the acquire
++		 * will pair with the WMB to ensure we then also see migrating.
++		 */
++		if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
++			return rq;
++		}
++		raw_spin_unlock(&rq->lock);
++		raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
++
++		while (unlikely(task_on_rq_migrating(p)))
++			cpu_relax();
++	}
++}
++
++static inline void
++rq_lock_irqsave(struct rq *rq, struct rq_flags *rf)
++	__acquires(rq->lock)
++{
++	raw_spin_lock_irqsave(&rq->lock, rf->flags);
++}
++
++static inline void
++rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
++	__releases(rq->lock)
++{
++	raw_spin_unlock_irqrestore(&rq->lock, rf->flags);
++}
++
++void raw_spin_rq_lock_nested(struct rq *rq, int subclass)
++{
++	raw_spinlock_t *lock;
++
++	/* Matches synchronize_rcu() in __sched_core_enable() */
++	preempt_disable();
++
++	for (;;) {
++		lock = __rq_lockp(rq);
++		raw_spin_lock_nested(lock, subclass);
++		if (likely(lock == __rq_lockp(rq))) {
++			/* preempt_count *MUST* be > 1 */
++			preempt_enable_no_resched();
++			return;
++		}
++		raw_spin_unlock(lock);
++	}
++}
++
++void raw_spin_rq_unlock(struct rq *rq)
++{
++	raw_spin_unlock(rq_lockp(rq));
++}
++
++/*
++ * RQ-clock updating methods:
++ */
++
++static void update_rq_clock_task(struct rq *rq, s64 delta)
++{
++/*
++ * In theory, the compile should just see 0 here, and optimize out the call
++ * to sched_rt_avg_update. But I don't trust it...
++ */
++	s64 __maybe_unused steal = 0, irq_delta = 0;
++
++#ifdef CONFIG_IRQ_TIME_ACCOUNTING
++	irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
++
++	/*
++	 * Since irq_time is only updated on {soft,}irq_exit, we might run into
++	 * this case when a previous update_rq_clock() happened inside a
++	 * {soft,}irq region.
++	 *
++	 * When this happens, we stop ->clock_task and only update the
++	 * prev_irq_time stamp to account for the part that fit, so that a next
++	 * update will consume the rest. This ensures ->clock_task is
++	 * monotonic.
++	 *
++	 * It does however cause some slight miss-attribution of {soft,}irq
++	 * time, a more accurate solution would be to update the irq_time using
++	 * the current rq->clock timestamp, except that would require using
++	 * atomic ops.
++	 */
++	if (irq_delta > delta)
++		irq_delta = delta;
++
++	rq->prev_irq_time += irq_delta;
++	delta -= irq_delta;
++#endif
++#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
++	if (static_key_false((&paravirt_steal_rq_enabled))) {
++		steal = paravirt_steal_clock(cpu_of(rq));
++		steal -= rq->prev_steal_time_rq;
++
++		if (unlikely(steal > delta))
++			steal = delta;
++
++		rq->prev_steal_time_rq += steal;
++		delta -= steal;
++	}
++#endif
++
++	rq->clock_task += delta;
++
++#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
++	if ((irq_delta + steal))
++		update_irq_load_avg(rq, irq_delta + steal);
++#endif
++}
++
++static inline void update_rq_clock(struct rq *rq)
++{
++	s64 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
++
++	if (unlikely(delta <= 0))
++		return;
++	rq->clock += delta;
++	update_rq_time_edge(rq);
++	update_rq_clock_task(rq, delta);
++}
++
++/*
++ * RQ Load update routine
++ */
++#define RQ_LOAD_HISTORY_BITS		(sizeof(s32) * 8ULL)
++#define RQ_UTIL_SHIFT			(8)
++#define RQ_LOAD_HISTORY_TO_UTIL(l)	(((l) >> (RQ_LOAD_HISTORY_BITS - 1 - RQ_UTIL_SHIFT)) & 0xff)
++
++#define LOAD_BLOCK(t)		((t) >> 17)
++#define LOAD_HALF_BLOCK(t)	((t) >> 16)
++#define BLOCK_MASK(t)		((t) & ((0x01 << 18) - 1))
++#define LOAD_BLOCK_BIT(b)	(1UL << (RQ_LOAD_HISTORY_BITS - 1 - (b)))
++#define CURRENT_LOAD_BIT	LOAD_BLOCK_BIT(0)
++
++static inline void rq_load_update(struct rq *rq)
++{
++	u64 time = rq->clock;
++	u64 delta = min(LOAD_BLOCK(time) - LOAD_BLOCK(rq->load_stamp),
++			RQ_LOAD_HISTORY_BITS - 1);
++	u64 prev = !!(rq->load_history & CURRENT_LOAD_BIT);
++	u64 curr = !!rq->nr_running;
++
++	if (delta) {
++		rq->load_history = rq->load_history >> delta;
++
++		if (delta < RQ_UTIL_SHIFT) {
++			rq->load_block += (~BLOCK_MASK(rq->load_stamp)) * prev;
++			if (!!LOAD_HALF_BLOCK(rq->load_block) ^ curr)
++				rq->load_history ^= LOAD_BLOCK_BIT(delta);
++		}
++
++		rq->load_block = BLOCK_MASK(time) * prev;
++	} else {
++		rq->load_block += (time - rq->load_stamp) * prev;
++	}
++	if (prev ^ curr)
++		rq->load_history ^= CURRENT_LOAD_BIT;
++	rq->load_stamp = time;
++}
++
++unsigned long rq_load_util(struct rq *rq, unsigned long max)
++{
++	return RQ_LOAD_HISTORY_TO_UTIL(rq->load_history) * (max >> RQ_UTIL_SHIFT);
++}
++
++#ifdef CONFIG_SMP
++unsigned long sched_cpu_util(int cpu, unsigned long max)
++{
++	return rq_load_util(cpu_rq(cpu), max);
++}
++#endif /* CONFIG_SMP */
++
++#ifdef CONFIG_CPU_FREQ
++/**
++ * cpufreq_update_util - Take a note about CPU utilization changes.
++ * @rq: Runqueue to carry out the update for.
++ * @flags: Update reason flags.
++ *
++ * This function is called by the scheduler on the CPU whose utilization is
++ * being updated.
++ *
++ * It can only be called from RCU-sched read-side critical sections.
++ *
++ * The way cpufreq is currently arranged requires it to evaluate the CPU
++ * performance state (frequency/voltage) on a regular basis to prevent it from
++ * being stuck in a completely inadequate performance level for too long.
++ * That is not guaranteed to happen if the updates are only triggered from CFS
++ * and DL, though, because they may not be coming in if only RT tasks are
++ * active all the time (or there are RT tasks only).
++ *
++ * As a workaround for that issue, this function is called periodically by the
++ * RT sched class to trigger extra cpufreq updates to prevent it from stalling,
++ * but that really is a band-aid.  Going forward it should be replaced with
++ * solutions targeted more specifically at RT tasks.
++ */
++static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
++{
++	struct update_util_data *data;
++
++#ifdef CONFIG_SMP
++	rq_load_update(rq);
++#endif
++	data = rcu_dereference_sched(*per_cpu_ptr(&cpufreq_update_util_data,
++						  cpu_of(rq)));
++	if (data)
++		data->func(data, rq_clock(rq), flags);
++}
++#else
++static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
++{
++#ifdef CONFIG_SMP
++	rq_load_update(rq);
++#endif
++}
++#endif /* CONFIG_CPU_FREQ */
++
++#ifdef CONFIG_NO_HZ_FULL
++/*
++ * Tick may be needed by tasks in the runqueue depending on their policy and
++ * requirements. If tick is needed, lets send the target an IPI to kick it out
++ * of nohz mode if necessary.
++ */
++static inline void sched_update_tick_dependency(struct rq *rq)
++{
++	int cpu = cpu_of(rq);
++
++	if (!tick_nohz_full_cpu(cpu))
++		return;
++
++	if (rq->nr_running < 2)
++		tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED);
++	else
++		tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED);
++}
++#else /* !CONFIG_NO_HZ_FULL */
++static inline void sched_update_tick_dependency(struct rq *rq) { }
++#endif
++
++bool sched_task_on_rq(struct task_struct *p)
++{
++	return task_on_rq_queued(p);
++}
++
++/*
++ * Add/Remove/Requeue task to/from the runqueue routines
++ * Context: rq->lock
++ */
++#define __SCHED_DEQUEUE_TASK(p, rq, flags, func)		\
++	psi_dequeue(p, flags & DEQUEUE_SLEEP);			\
++	sched_info_dequeue(rq, p);				\
++								\
++	list_del(&p->sq_node);					\
++	if (list_empty(&rq->queue.heads[p->sq_idx])) {		\
++		clear_bit(sched_idx2prio(p->sq_idx, rq),	\
++			  rq->queue.bitmap);			\
++		func;						\
++	}
++
++#define __SCHED_ENQUEUE_TASK(p, rq, flags)				\
++	sched_info_enqueue(rq, p);					\
++	psi_enqueue(p, flags);						\
++									\
++	p->sq_idx = task_sched_prio_idx(p, rq);				\
++	list_add_tail(&p->sq_node, &rq->queue.heads[p->sq_idx]);	\
++	set_bit(sched_idx2prio(p->sq_idx, rq), rq->queue.bitmap);
++
++static inline void dequeue_task(struct task_struct *p, struct rq *rq, int flags)
++{
++	lockdep_assert_held(&rq->lock);
++
++	/*printk(KERN_INFO "sched: dequeue(%d) %px %016llx\n", cpu_of(rq), p, p->priodl);*/
++	WARN_ONCE(task_rq(p) != rq, "sched: dequeue task reside on cpu%d from cpu%d\n",
++		  task_cpu(p), cpu_of(rq));
++
++	__SCHED_DEQUEUE_TASK(p, rq, flags, update_sched_rq_watermark(rq));
++	--rq->nr_running;
++#ifdef CONFIG_SMP
++	if (1 == rq->nr_running)
++		cpumask_clear_cpu(cpu_of(rq), &sched_rq_pending_mask);
++#endif
++
++	sched_update_tick_dependency(rq);
++}
++
++static inline void enqueue_task(struct task_struct *p, struct rq *rq, int flags)
++{
++	lockdep_assert_held(&rq->lock);
++
++	/*printk(KERN_INFO "sched: enqueue(%d) %px %016llx\n", cpu_of(rq), p, p->priodl);*/
++	WARN_ONCE(task_rq(p) != rq, "sched: enqueue task reside on cpu%d to cpu%d\n",
++		  task_cpu(p), cpu_of(rq));
++
++	__SCHED_ENQUEUE_TASK(p, rq, flags);
++	update_sched_rq_watermark(rq);
++	++rq->nr_running;
++#ifdef CONFIG_SMP
++	if (2 == rq->nr_running)
++		cpumask_set_cpu(cpu_of(rq), &sched_rq_pending_mask);
++#endif
++
++	sched_update_tick_dependency(rq);
++}
++
++static inline void requeue_task(struct task_struct *p, struct rq *rq)
++{
++	int idx;
++
++	lockdep_assert_held(&rq->lock);
++	/*printk(KERN_INFO "sched: requeue(%d) %px %016llx\n", cpu_of(rq), p, p->priodl);*/
++	WARN_ONCE(task_rq(p) != rq, "sched: cpu[%d] requeue task reside on cpu%d\n",
++		  cpu_of(rq), task_cpu(p));
++
++	idx = task_sched_prio_idx(p, rq);
++
++	list_del(&p->sq_node);
++	list_add_tail(&p->sq_node, &rq->queue.heads[idx]);
++	if (idx != p->sq_idx) {
++		if (list_empty(&rq->queue.heads[p->sq_idx]))
++			clear_bit(sched_idx2prio(p->sq_idx, rq),
++				  rq->queue.bitmap);
++		p->sq_idx = idx;
++		set_bit(sched_idx2prio(p->sq_idx, rq), rq->queue.bitmap);
++		update_sched_rq_watermark(rq);
++	}
++}
++
++/*
++ * cmpxchg based fetch_or, macro so it works for different integer types
++ */
++#define fetch_or(ptr, mask)						\
++	({								\
++		typeof(ptr) _ptr = (ptr);				\
++		typeof(mask) _mask = (mask);				\
++		typeof(*_ptr) _old, _val = *_ptr;			\
++									\
++		for (;;) {						\
++			_old = cmpxchg(_ptr, _val, _val | _mask);	\
++			if (_old == _val)				\
++				break;					\
++			_val = _old;					\
++		}							\
++	_old;								\
++})
++
++#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
++/*
++ * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
++ * this avoids any races wrt polling state changes and thereby avoids
++ * spurious IPIs.
++ */
++static bool set_nr_and_not_polling(struct task_struct *p)
++{
++	struct thread_info *ti = task_thread_info(p);
++	return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG);
++}
++
++/*
++ * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
++ *
++ * If this returns true, then the idle task promises to call
++ * sched_ttwu_pending() and reschedule soon.
++ */
++static bool set_nr_if_polling(struct task_struct *p)
++{
++	struct thread_info *ti = task_thread_info(p);
++	typeof(ti->flags) old, val = READ_ONCE(ti->flags);
++
++	for (;;) {
++		if (!(val & _TIF_POLLING_NRFLAG))
++			return false;
++		if (val & _TIF_NEED_RESCHED)
++			return true;
++		old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED);
++		if (old == val)
++			break;
++		val = old;
++	}
++	return true;
++}
++
++#else
++static bool set_nr_and_not_polling(struct task_struct *p)
++{
++	set_tsk_need_resched(p);
++	return true;
++}
++
++#ifdef CONFIG_SMP
++static bool set_nr_if_polling(struct task_struct *p)
++{
++	return false;
++}
++#endif
++#endif
++
++static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
++{
++	struct wake_q_node *node = &task->wake_q;
++
++	/*
++	 * Atomically grab the task, if ->wake_q is !nil already it means
++	 * it's already queued (either by us or someone else) and will get the
++	 * wakeup due to that.
++	 *
++	 * In order to ensure that a pending wakeup will observe our pending
++	 * state, even in the failed case, an explicit smp_mb() must be used.
++	 */
++	smp_mb__before_atomic();
++	if (unlikely(cmpxchg_relaxed(&node->next, NULL, WAKE_Q_TAIL)))
++		return false;
++
++	/*
++	 * The head is context local, there can be no concurrency.
++	 */
++	*head->lastp = node;
++	head->lastp = &node->next;
++	return true;
++}
++
++/**
++ * wake_q_add() - queue a wakeup for 'later' waking.
++ * @head: the wake_q_head to add @task to
++ * @task: the task to queue for 'later' wakeup
++ *
++ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
++ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
++ * instantly.
++ *
++ * This function must be used as-if it were wake_up_process(); IOW the task
++ * must be ready to be woken at this location.
++ */
++void wake_q_add(struct wake_q_head *head, struct task_struct *task)
++{
++	if (__wake_q_add(head, task))
++		get_task_struct(task);
++}
++
++/**
++ * wake_q_add_safe() - safely queue a wakeup for 'later' waking.
++ * @head: the wake_q_head to add @task to
++ * @task: the task to queue for 'later' wakeup
++ *
++ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
++ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
++ * instantly.
++ *
++ * This function must be used as-if it were wake_up_process(); IOW the task
++ * must be ready to be woken at this location.
++ *
++ * This function is essentially a task-safe equivalent to wake_q_add(). Callers
++ * that already hold reference to @task can call the 'safe' version and trust
++ * wake_q to do the right thing depending whether or not the @task is already
++ * queued for wakeup.
++ */
++void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
++{
++	if (!__wake_q_add(head, task))
++		put_task_struct(task);
++}
++
++void wake_up_q(struct wake_q_head *head)
++{
++	struct wake_q_node *node = head->first;
++
++	while (node != WAKE_Q_TAIL) {
++		struct task_struct *task;
++
++		task = container_of(node, struct task_struct, wake_q);
++		/* task can safely be re-inserted now: */
++		node = node->next;
++		task->wake_q.next = NULL;
++
++		/*
++		 * wake_up_process() executes a full barrier, which pairs with
++		 * the queueing in wake_q_add() so as not to miss wakeups.
++		 */
++		wake_up_process(task);
++		put_task_struct(task);
++	}
++}
++
++/*
++ * resched_curr - mark rq's current task 'to be rescheduled now'.
++ *
++ * On UP this means the setting of the need_resched flag, on SMP it
++ * might also involve a cross-CPU call to trigger the scheduler on
++ * the target CPU.
++ */
++void resched_curr(struct rq *rq)
++{
++	struct task_struct *curr = rq->curr;
++	int cpu;
++
++	lockdep_assert_held(&rq->lock);
++
++	if (test_tsk_need_resched(curr))
++		return;
++
++	cpu = cpu_of(rq);
++	if (cpu == smp_processor_id()) {
++		set_tsk_need_resched(curr);
++		set_preempt_need_resched();
++		return;
++	}
++
++	if (set_nr_and_not_polling(curr))
++		smp_send_reschedule(cpu);
++	else
++		trace_sched_wake_idle_without_ipi(cpu);
++}
++
++void resched_cpu(int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++	unsigned long flags;
++
++	raw_spin_lock_irqsave(&rq->lock, flags);
++	if (cpu_online(cpu) || cpu == smp_processor_id())
++		resched_curr(cpu_rq(cpu));
++	raw_spin_unlock_irqrestore(&rq->lock, flags);
++}
++
++#ifdef CONFIG_SMP
++#ifdef CONFIG_NO_HZ_COMMON
++void nohz_balance_enter_idle(int cpu) {}
++
++void select_nohz_load_balancer(int stop_tick) {}
++
++void set_cpu_sd_state_idle(void) {}
++
++/*
++ * In the semi idle case, use the nearest busy CPU for migrating timers
++ * from an idle CPU.  This is good for power-savings.
++ *
++ * We don't do similar optimization for completely idle system, as
++ * selecting an idle CPU will add more delays to the timers than intended
++ * (as that CPU's timer base may not be uptodate wrt jiffies etc).
++ */
++int get_nohz_timer_target(void)
++{
++	int i, cpu = smp_processor_id(), default_cpu = -1;
++	struct cpumask *mask;
++	const struct cpumask *hk_mask;
++
++	if (housekeeping_cpu(cpu, HK_FLAG_TIMER)) {
++		if (!idle_cpu(cpu))
++			return cpu;
++		default_cpu = cpu;
++	}
++
++	hk_mask = housekeeping_cpumask(HK_FLAG_TIMER);
++
++	for (mask = per_cpu(sched_cpu_topo_masks, cpu) + 1;
++	     mask < per_cpu(sched_cpu_topo_end_mask, cpu); mask++)
++		for_each_cpu_and(i, mask, hk_mask)
++			if (!idle_cpu(i))
++				return i;
++
++	if (default_cpu == -1)
++		default_cpu = housekeeping_any_cpu(HK_FLAG_TIMER);
++	cpu = default_cpu;
++
++	return cpu;
++}
++
++/*
++ * When add_timer_on() enqueues a timer into the timer wheel of an
++ * idle CPU then this timer might expire before the next timer event
++ * which is scheduled to wake up that CPU. In case of a completely
++ * idle system the next event might even be infinite time into the
++ * future. wake_up_idle_cpu() ensures that the CPU is woken up and
++ * leaves the inner idle loop so the newly added timer is taken into
++ * account when the CPU goes back to idle and evaluates the timer
++ * wheel for the next timer event.
++ */
++static inline void wake_up_idle_cpu(int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++
++	if (cpu == smp_processor_id())
++		return;
++
++	if (set_nr_and_not_polling(rq->idle))
++		smp_send_reschedule(cpu);
++	else
++		trace_sched_wake_idle_without_ipi(cpu);
++}
++
++static inline bool wake_up_full_nohz_cpu(int cpu)
++{
++	/*
++	 * We just need the target to call irq_exit() and re-evaluate
++	 * the next tick. The nohz full kick at least implies that.
++	 * If needed we can still optimize that later with an
++	 * empty IRQ.
++	 */
++	if (cpu_is_offline(cpu))
++		return true;  /* Don't try to wake offline CPUs. */
++	if (tick_nohz_full_cpu(cpu)) {
++		if (cpu != smp_processor_id() ||
++		    tick_nohz_tick_stopped())
++			tick_nohz_full_kick_cpu(cpu);
++		return true;
++	}
++
++	return false;
++}
++
++void wake_up_nohz_cpu(int cpu)
++{
++	if (!wake_up_full_nohz_cpu(cpu))
++		wake_up_idle_cpu(cpu);
++}
++
++static void nohz_csd_func(void *info)
++{
++	struct rq *rq = info;
++	int cpu = cpu_of(rq);
++	unsigned int flags;
++
++	/*
++	 * Release the rq::nohz_csd.
++	 */
++	flags = atomic_fetch_andnot(NOHZ_KICK_MASK, nohz_flags(cpu));
++	WARN_ON(!(flags & NOHZ_KICK_MASK));
++
++	rq->idle_balance = idle_cpu(cpu);
++	if (rq->idle_balance && !need_resched()) {
++		rq->nohz_idle_balance = flags;
++		raise_softirq_irqoff(SCHED_SOFTIRQ);
++	}
++}
++
++#endif /* CONFIG_NO_HZ_COMMON */
++#endif /* CONFIG_SMP */
++
++static inline void check_preempt_curr(struct rq *rq)
++{
++	if (sched_rq_first_task(rq) != rq->curr)
++		resched_curr(rq);
++}
++
++#ifdef CONFIG_SCHED_HRTICK
++/*
++ * Use HR-timers to deliver accurate preemption points.
++ */
++
++static void hrtick_clear(struct rq *rq)
++{
++	if (hrtimer_active(&rq->hrtick_timer))
++		hrtimer_cancel(&rq->hrtick_timer);
++}
++
++/*
++ * High-resolution timer tick.
++ * Runs from hardirq context with interrupts disabled.
++ */
++static enum hrtimer_restart hrtick(struct hrtimer *timer)
++{
++	struct rq *rq = container_of(timer, struct rq, hrtick_timer);
++
++	WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
++
++	raw_spin_lock(&rq->lock);
++	resched_curr(rq);
++	raw_spin_unlock(&rq->lock);
++
++	return HRTIMER_NORESTART;
++}
++
++/*
++ * Use hrtick when:
++ *  - enabled by features
++ *  - hrtimer is actually high res
++ */
++static inline int hrtick_enabled(struct rq *rq)
++{
++	/**
++	 * Alt schedule FW doesn't support sched_feat yet
++	if (!sched_feat(HRTICK))
++		return 0;
++	*/
++	if (!cpu_active(cpu_of(rq)))
++		return 0;
++	return hrtimer_is_hres_active(&rq->hrtick_timer);
++}
++
++#ifdef CONFIG_SMP
++
++static void __hrtick_restart(struct rq *rq)
++{
++	struct hrtimer *timer = &rq->hrtick_timer;
++	ktime_t time = rq->hrtick_time;
++
++	hrtimer_start(timer, time, HRTIMER_MODE_ABS_PINNED_HARD);
++}
++
++/*
++ * called from hardirq (IPI) context
++ */
++static void __hrtick_start(void *arg)
++{
++	struct rq *rq = arg;
++
++	raw_spin_lock(&rq->lock);
++	__hrtick_restart(rq);
++	raw_spin_unlock(&rq->lock);
++}
++
++/*
++ * Called to set the hrtick timer state.
++ *
++ * called with rq->lock held and irqs disabled
++ */
++void hrtick_start(struct rq *rq, u64 delay)
++{
++	struct hrtimer *timer = &rq->hrtick_timer;
++	s64 delta;
++
++	/*
++	 * Don't schedule slices shorter than 10000ns, that just
++	 * doesn't make sense and can cause timer DoS.
++	 */
++	delta = max_t(s64, delay, 10000LL);
++
++	rq->hrtick_time = ktime_add_ns(timer->base->get_time(), delta);
++
++	if (rq == this_rq())
++		__hrtick_restart(rq);
++	else
++		smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
++}
++
++#else
++/*
++ * Called to set the hrtick timer state.
++ *
++ * called with rq->lock held and irqs disabled
++ */
++void hrtick_start(struct rq *rq, u64 delay)
++{
++	/*
++	 * Don't schedule slices shorter than 10000ns, that just
++	 * doesn't make sense. Rely on vruntime for fairness.
++	 */
++	delay = max_t(u64, delay, 10000LL);
++	hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
++		      HRTIMER_MODE_REL_PINNED_HARD);
++}
++#endif /* CONFIG_SMP */
++
++static void hrtick_rq_init(struct rq *rq)
++{
++#ifdef CONFIG_SMP
++	INIT_CSD(&rq->hrtick_csd, __hrtick_start, rq);
++#endif
++
++	hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
++	rq->hrtick_timer.function = hrtick;
++}
++#else	/* CONFIG_SCHED_HRTICK */
++static inline int hrtick_enabled(struct rq *rq)
++{
++	return 0;
++}
++
++static inline void hrtick_clear(struct rq *rq)
++{
++}
++
++static inline void hrtick_rq_init(struct rq *rq)
++{
++}
++#endif	/* CONFIG_SCHED_HRTICK */
++
++static inline int __normal_prio(int policy, int rt_prio, int static_prio)
++{
++	return rt_policy(policy) ? (MAX_RT_PRIO - 1 - rt_prio) :
++		static_prio + MAX_PRIORITY_ADJ;
++}
++
++/*
++ * Calculate the expected normal priority: i.e. priority
++ * without taking RT-inheritance into account. Might be
++ * boosted by interactivity modifiers. Changes upon fork,
++ * setprio syscalls, and whenever the interactivity
++ * estimator recalculates.
++ */
++static inline int normal_prio(struct task_struct *p)
++{
++	return __normal_prio(p->policy, p->rt_priority, p->static_prio);
++}
++
++/*
++ * Calculate the current priority, i.e. the priority
++ * taken into account by the scheduler. This value might
++ * be boosted by RT tasks as it will be RT if the task got
++ * RT-boosted. If not then it returns p->normal_prio.
++ */
++static int effective_prio(struct task_struct *p)
++{
++	p->normal_prio = normal_prio(p);
++	/*
++	 * If we are RT tasks or we were boosted to RT priority,
++	 * keep the priority unchanged. Otherwise, update priority
++	 * to the normal priority:
++	 */
++	if (!rt_prio(p->prio))
++		return p->normal_prio;
++	return p->prio;
++}
++
++/*
++ * activate_task - move a task to the runqueue.
++ *
++ * Context: rq->lock
++ */
++static void activate_task(struct task_struct *p, struct rq *rq)
++{
++	enqueue_task(p, rq, ENQUEUE_WAKEUP);
++	p->on_rq = TASK_ON_RQ_QUEUED;
++
++	/*
++	 * If in_iowait is set, the code below may not trigger any cpufreq
++	 * utilization updates, so do it here explicitly with the IOWAIT flag
++	 * passed.
++	 */
++	cpufreq_update_util(rq, SCHED_CPUFREQ_IOWAIT * p->in_iowait);
++}
++
++/*
++ * deactivate_task - remove a task from the runqueue.
++ *
++ * Context: rq->lock
++ */
++static inline void deactivate_task(struct task_struct *p, struct rq *rq)
++{
++	dequeue_task(p, rq, DEQUEUE_SLEEP);
++	p->on_rq = 0;
++	cpufreq_update_util(rq, 0);
++}
++
++static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
++{
++#ifdef CONFIG_SMP
++	/*
++	 * After ->cpu is set up to a new value, task_access_lock(p, ...) can be
++	 * successfully executed on another CPU. We must ensure that updates of
++	 * per-task data have been completed by this moment.
++	 */
++	smp_wmb();
++
++#ifdef CONFIG_THREAD_INFO_IN_TASK
++	WRITE_ONCE(p->cpu, cpu);
++#else
++	WRITE_ONCE(task_thread_info(p)->cpu, cpu);
++#endif
++#endif
++}
++
++static inline bool is_migration_disabled(struct task_struct *p)
++{
++#ifdef CONFIG_SMP
++	return p->migration_disabled;
++#else
++	return false;
++#endif
++}
++
++#define SCA_CHECK		0x01
++#define SCA_USER		0x08
++
++#ifdef CONFIG_SMP
++
++void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
++{
++#ifdef CONFIG_SCHED_DEBUG
++	unsigned int state = READ_ONCE(p->__state);
++
++	/*
++	 * We should never call set_task_cpu() on a blocked task,
++	 * ttwu() will sort out the placement.
++	 */
++	WARN_ON_ONCE(state != TASK_RUNNING && state != TASK_WAKING && !p->on_rq);
++
++#ifdef CONFIG_LOCKDEP
++	/*
++	 * The caller should hold either p->pi_lock or rq->lock, when changing
++	 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
++	 *
++	 * sched_move_task() holds both and thus holding either pins the cgroup,
++	 * see task_group().
++	 */
++	WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
++				      lockdep_is_held(&task_rq(p)->lock)));
++#endif
++	/*
++	 * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
++	 */
++	WARN_ON_ONCE(!cpu_online(new_cpu));
++
++	WARN_ON_ONCE(is_migration_disabled(p));
++#endif
++	if (task_cpu(p) == new_cpu)
++		return;
++	trace_sched_migrate_task(p, new_cpu);
++	rseq_migrate(p);
++	perf_event_task_migrate(p);
++
++	__set_task_cpu(p, new_cpu);
++}
++
++#define MDF_FORCE_ENABLED	0x80
++
++static void
++__do_set_cpus_ptr(struct task_struct *p, const struct cpumask *new_mask)
++{
++	/*
++	 * This here violates the locking rules for affinity, since we're only
++	 * supposed to change these variables while holding both rq->lock and
++	 * p->pi_lock.
++	 *
++	 * HOWEVER, it magically works, because ttwu() is the only code that
++	 * accesses these variables under p->pi_lock and only does so after
++	 * smp_cond_load_acquire(&p->on_cpu, !VAL), and we're in __schedule()
++	 * before finish_task().
++	 *
++	 * XXX do further audits, this smells like something putrid.
++	 */
++	SCHED_WARN_ON(!p->on_cpu);
++	p->cpus_ptr = new_mask;
++}
++
++void migrate_disable(void)
++{
++	struct task_struct *p = current;
++	int cpu;
++
++	if (p->migration_disabled) {
++		p->migration_disabled++;
++		return;
++	}
++
++	preempt_disable();
++	cpu = smp_processor_id();
++	if (cpumask_test_cpu(cpu, &p->cpus_mask)) {
++		cpu_rq(cpu)->nr_pinned++;
++		p->migration_disabled = 1;
++		p->migration_flags &= ~MDF_FORCE_ENABLED;
++
++		/*
++		 * Violates locking rules! see comment in __do_set_cpus_ptr().
++		 */
++		if (p->cpus_ptr == &p->cpus_mask)
++			__do_set_cpus_ptr(p, cpumask_of(cpu));
++	}
++	preempt_enable();
++}
++EXPORT_SYMBOL_GPL(migrate_disable);
++
++void migrate_enable(void)
++{
++	struct task_struct *p = current;
++
++	if (0 == p->migration_disabled)
++		return;
++
++	if (p->migration_disabled > 1) {
++		p->migration_disabled--;
++		return;
++	}
++
++	/*
++	 * Ensure stop_task runs either before or after this, and that
++	 * __set_cpus_allowed_ptr(SCA_MIGRATE_ENABLE) doesn't schedule().
++	 */
++	preempt_disable();
++	/*
++	 * Assumption: current should be running on allowed cpu
++	 */
++	WARN_ON_ONCE(!cpumask_test_cpu(smp_processor_id(), &p->cpus_mask));
++	if (p->cpus_ptr != &p->cpus_mask)
++		__do_set_cpus_ptr(p, &p->cpus_mask);
++	/*
++	 * Mustn't clear migration_disabled() until cpus_ptr points back at the
++	 * regular cpus_mask, otherwise things that race (eg.
++	 * select_fallback_rq) get confused.
++	 */
++	barrier();
++	p->migration_disabled = 0;
++	this_rq()->nr_pinned--;
++	preempt_enable();
++}
++EXPORT_SYMBOL_GPL(migrate_enable);
++
++static inline bool rq_has_pinned_tasks(struct rq *rq)
++{
++	return rq->nr_pinned;
++}
++
++/*
++ * Per-CPU kthreads are allowed to run on !active && online CPUs, see
++ * __set_cpus_allowed_ptr() and select_fallback_rq().
++ */
++static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
++{
++	/* When not in the task's cpumask, no point in looking further. */
++	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
++		return false;
++
++	/* migrate_disabled() must be allowed to finish. */
++	if (is_migration_disabled(p))
++		return cpu_online(cpu);
++
++	/* Non kernel threads are not allowed during either online or offline. */
++	if (!(p->flags & PF_KTHREAD))
++		return cpu_active(cpu) && task_cpu_possible(cpu, p);
++
++	/* KTHREAD_IS_PER_CPU is always allowed. */
++	if (kthread_is_per_cpu(p))
++		return cpu_online(cpu);
++
++	/* Regular kernel threads don't get to stay during offline. */
++	if (cpu_dying(cpu))
++		return false;
++
++	/* But are allowed during online. */
++	return cpu_online(cpu);
++}
++
++/*
++ * This is how migration works:
++ *
++ * 1) we invoke migration_cpu_stop() on the target CPU using
++ *    stop_one_cpu().
++ * 2) stopper starts to run (implicitly forcing the migrated thread
++ *    off the CPU)
++ * 3) it checks whether the migrated task is still in the wrong runqueue.
++ * 4) if it's in the wrong runqueue then the migration thread removes
++ *    it and puts it into the right queue.
++ * 5) stopper completes and stop_one_cpu() returns and the migration
++ *    is done.
++ */
++
++/*
++ * move_queued_task - move a queued task to new rq.
++ *
++ * Returns (locked) new rq. Old rq's lock is released.
++ */
++static struct rq *move_queued_task(struct rq *rq, struct task_struct *p, int
++				   new_cpu)
++{
++	lockdep_assert_held(&rq->lock);
++
++	WRITE_ONCE(p->on_rq, TASK_ON_RQ_MIGRATING);
++	dequeue_task(p, rq, 0);
++	set_task_cpu(p, new_cpu);
++	raw_spin_unlock(&rq->lock);
++
++	rq = cpu_rq(new_cpu);
++
++	raw_spin_lock(&rq->lock);
++	BUG_ON(task_cpu(p) != new_cpu);
++	sched_task_sanity_check(p, rq);
++	enqueue_task(p, rq, 0);
++	p->on_rq = TASK_ON_RQ_QUEUED;
++	check_preempt_curr(rq);
++
++	return rq;
++}
++
++struct migration_arg {
++	struct task_struct *task;
++	int dest_cpu;
++};
++
++/*
++ * Move (not current) task off this CPU, onto the destination CPU. We're doing
++ * this because either it can't run here any more (set_cpus_allowed()
++ * away from this CPU, or CPU going down), or because we're
++ * attempting to rebalance this task on exec (sched_exec).
++ *
++ * So we race with normal scheduler movements, but that's OK, as long
++ * as the task is no longer on this CPU.
++ */
++static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int
++				 dest_cpu)
++{
++	/* Affinity changed (again). */
++	if (!is_cpu_allowed(p, dest_cpu))
++		return rq;
++
++	update_rq_clock(rq);
++	return move_queued_task(rq, p, dest_cpu);
++}
++
++/*
++ * migration_cpu_stop - this will be executed by a highprio stopper thread
++ * and performs thread migration by bumping thread off CPU then
++ * 'pushing' onto another runqueue.
++ */
++static int migration_cpu_stop(void *data)
++{
++	struct migration_arg *arg = data;
++	struct task_struct *p = arg->task;
++	struct rq *rq = this_rq();
++	unsigned long flags;
++
++	/*
++	 * The original target CPU might have gone down and we might
++	 * be on another CPU but it doesn't matter.
++	 */
++	local_irq_save(flags);
++	/*
++	 * We need to explicitly wake pending tasks before running
++	 * __migrate_task() such that we will not miss enforcing cpus_ptr
++	 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
++	 */
++	flush_smp_call_function_from_idle();
++
++	raw_spin_lock(&p->pi_lock);
++	raw_spin_lock(&rq->lock);
++	/*
++	 * If task_rq(p) != rq, it cannot be migrated here, because we're
++	 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
++	 * we're holding p->pi_lock.
++	 */
++	if (task_rq(p) == rq && task_on_rq_queued(p))
++		rq = __migrate_task(rq, p, arg->dest_cpu);
++	raw_spin_unlock(&rq->lock);
++	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++
++	return 0;
++}
++
++static inline void
++set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
++{
++	cpumask_copy(&p->cpus_mask, new_mask);
++	p->nr_cpus_allowed = cpumask_weight(new_mask);
++}
++
++static void
++__do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
++{
++	lockdep_assert_held(&p->pi_lock);
++	set_cpus_allowed_common(p, new_mask);
++}
++
++void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
++{
++	__do_set_cpus_allowed(p, new_mask);
++}
++
++int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src,
++		      int node)
++{
++	if (!src->user_cpus_ptr)
++		return 0;
++
++	dst->user_cpus_ptr = kmalloc_node(cpumask_size(), GFP_KERNEL, node);
++	if (!dst->user_cpus_ptr)
++		return -ENOMEM;
++
++	cpumask_copy(dst->user_cpus_ptr, src->user_cpus_ptr);
++	return 0;
++}
++
++static inline struct cpumask *clear_user_cpus_ptr(struct task_struct *p)
++{
++	struct cpumask *user_mask = NULL;
++
++	swap(p->user_cpus_ptr, user_mask);
++
++	return user_mask;
++}
++
++void release_user_cpus_ptr(struct task_struct *p)
++{
++	kfree(clear_user_cpus_ptr(p));
++}
++
++#endif
++
++/**
++ * task_curr - is this task currently executing on a CPU?
++ * @p: the task in question.
++ *
++ * Return: 1 if the task is currently executing. 0 otherwise.
++ */
++inline int task_curr(const struct task_struct *p)
++{
++	return cpu_curr(task_cpu(p)) == p;
++}
++
++#ifdef CONFIG_SMP
++/*
++ * wait_task_inactive - wait for a thread to unschedule.
++ *
++ * If @match_state is nonzero, it's the @p->state value just checked and
++ * not expected to change.  If it changes, i.e. @p might have woken up,
++ * then return zero.  When we succeed in waiting for @p to be off its CPU,
++ * we return a positive number (its total switch count).  If a second call
++ * a short while later returns the same number, the caller can be sure that
++ * @p has remained unscheduled the whole time.
++ *
++ * The caller must ensure that the task *will* unschedule sometime soon,
++ * else this function might spin for a *long* time. This function can't
++ * be called with interrupts off, or it may introduce deadlock with
++ * smp_call_function() if an IPI is sent by the same process we are
++ * waiting to become inactive.
++ */
++unsigned long wait_task_inactive(struct task_struct *p, unsigned int match_state)
++{
++	unsigned long flags;
++	bool running, on_rq;
++	unsigned long ncsw;
++	struct rq *rq;
++	raw_spinlock_t *lock;
++
++	for (;;) {
++		rq = task_rq(p);
++
++		/*
++		 * If the task is actively running on another CPU
++		 * still, just relax and busy-wait without holding
++		 * any locks.
++		 *
++		 * NOTE! Since we don't hold any locks, it's not
++		 * even sure that "rq" stays as the right runqueue!
++		 * But we don't care, since this will return false
++		 * if the runqueue has changed and p is actually now
++		 * running somewhere else!
++		 */
++		while (task_running(p) && p == rq->curr) {
++			if (match_state && unlikely(READ_ONCE(p->__state) != match_state))
++				return 0;
++			cpu_relax();
++		}
++
++		/*
++		 * Ok, time to look more closely! We need the rq
++		 * lock now, to be *sure*. If we're wrong, we'll
++		 * just go back and repeat.
++		 */
++		task_access_lock_irqsave(p, &lock, &flags);
++		trace_sched_wait_task(p);
++		running = task_running(p);
++		on_rq = p->on_rq;
++		ncsw = 0;
++		if (!match_state || READ_ONCE(p->__state) == match_state)
++			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
++		task_access_unlock_irqrestore(p, lock, &flags);
++
++		/*
++		 * If it changed from the expected state, bail out now.
++		 */
++		if (unlikely(!ncsw))
++			break;
++
++		/*
++		 * Was it really running after all now that we
++		 * checked with the proper locks actually held?
++		 *
++		 * Oops. Go back and try again..
++		 */
++		if (unlikely(running)) {
++			cpu_relax();
++			continue;
++		}
++
++		/*
++		 * It's not enough that it's not actively running,
++		 * it must be off the runqueue _entirely_, and not
++		 * preempted!
++		 *
++		 * So if it was still runnable (but just not actively
++		 * running right now), it's preempted, and we should
++		 * yield - it could be a while.
++		 */
++		if (unlikely(on_rq)) {
++			ktime_t to = NSEC_PER_SEC / HZ;
++
++			set_current_state(TASK_UNINTERRUPTIBLE);
++			schedule_hrtimeout(&to, HRTIMER_MODE_REL);
++			continue;
++		}
++
++		/*
++		 * Ahh, all good. It wasn't running, and it wasn't
++		 * runnable, which means that it will never become
++		 * running in the future either. We're all done!
++		 */
++		break;
++	}
++
++	return ncsw;
++}
++
++/***
++ * kick_process - kick a running thread to enter/exit the kernel
++ * @p: the to-be-kicked thread
++ *
++ * Cause a process which is running on another CPU to enter
++ * kernel-mode, without any delay. (to get signals handled.)
++ *
++ * NOTE: this function doesn't have to take the runqueue lock,
++ * because all it wants to ensure is that the remote task enters
++ * the kernel. If the IPI races and the task has been migrated
++ * to another CPU then no harm is done and the purpose has been
++ * achieved as well.
++ */
++void kick_process(struct task_struct *p)
++{
++	int cpu;
++
++	preempt_disable();
++	cpu = task_cpu(p);
++	if ((cpu != smp_processor_id()) && task_curr(p))
++		smp_send_reschedule(cpu);
++	preempt_enable();
++}
++EXPORT_SYMBOL_GPL(kick_process);
++
++/*
++ * ->cpus_ptr is protected by both rq->lock and p->pi_lock
++ *
++ * A few notes on cpu_active vs cpu_online:
++ *
++ *  - cpu_active must be a subset of cpu_online
++ *
++ *  - on CPU-up we allow per-CPU kthreads on the online && !active CPU,
++ *    see __set_cpus_allowed_ptr(). At this point the newly online
++ *    CPU isn't yet part of the sched domains, and balancing will not
++ *    see it.
++ *
++ *  - on cpu-down we clear cpu_active() to mask the sched domains and
++ *    avoid the load balancer to place new tasks on the to be removed
++ *    CPU. Existing tasks will remain running there and will be taken
++ *    off.
++ *
++ * This means that fallback selection must not select !active CPUs.
++ * And can assume that any active CPU must be online. Conversely
++ * select_task_rq() below may allow selection of !active CPUs in order
++ * to satisfy the above rules.
++ */
++static int select_fallback_rq(int cpu, struct task_struct *p)
++{
++	int nid = cpu_to_node(cpu);
++	const struct cpumask *nodemask = NULL;
++	enum { cpuset, possible, fail } state = cpuset;
++	int dest_cpu;
++
++	/*
++	 * If the node that the CPU is on has been offlined, cpu_to_node()
++	 * will return -1. There is no CPU on the node, and we should
++	 * select the CPU on the other node.
++	 */
++	if (nid != -1) {
++		nodemask = cpumask_of_node(nid);
++
++		/* Look for allowed, online CPU in same node. */
++		for_each_cpu(dest_cpu, nodemask) {
++			if (is_cpu_allowed(p, dest_cpu))
++				return dest_cpu;
++		}
++	}
++
++	for (;;) {
++		/* Any allowed, online CPU? */
++		for_each_cpu(dest_cpu, p->cpus_ptr) {
++			if (!is_cpu_allowed(p, dest_cpu))
++				continue;
++			goto out;
++		}
++
++		/* No more Mr. Nice Guy. */
++		switch (state) {
++		case cpuset:
++			if (cpuset_cpus_allowed_fallback(p)) {
++				state = possible;
++				break;
++			}
++			fallthrough;
++		case possible:
++			/*
++			 * XXX When called from select_task_rq() we only
++			 * hold p->pi_lock and again violate locking order.
++			 *
++			 * More yuck to audit.
++			 */
++			do_set_cpus_allowed(p, task_cpu_possible_mask(p));
++			state = fail;
++			break;
++
++		case fail:
++			BUG();
++			break;
++		}
++	}
++
++out:
++	if (state != cpuset) {
++		/*
++		 * Don't tell them about moving exiting tasks or
++		 * kernel threads (both mm NULL), since they never
++		 * leave kernel.
++		 */
++		if (p->mm && printk_ratelimit()) {
++			printk_deferred("process %d (%s) no longer affine to cpu%d\n",
++					task_pid_nr(p), p->comm, cpu);
++		}
++	}
++
++	return dest_cpu;
++}
++
++static inline int select_task_rq(struct task_struct *p)
++{
++	cpumask_t chk_mask, tmp;
++
++	if (unlikely(!cpumask_and(&chk_mask, p->cpus_ptr, cpu_active_mask)))
++		return select_fallback_rq(task_cpu(p), p);
++
++	if (
++#ifdef CONFIG_SCHED_SMT
++	    cpumask_and(&tmp, &chk_mask, &sched_sg_idle_mask) ||
++#endif
++	    cpumask_and(&tmp, &chk_mask, sched_rq_watermark) ||
++	    cpumask_and(&tmp, &chk_mask,
++			sched_rq_watermark + SCHED_BITS - task_sched_prio(p)))
++		return best_mask_cpu(task_cpu(p), &tmp);
++
++	return best_mask_cpu(task_cpu(p), &chk_mask);
++}
++
++void sched_set_stop_task(int cpu, struct task_struct *stop)
++{
++	static struct lock_class_key stop_pi_lock;
++	struct sched_param stop_param = { .sched_priority = STOP_PRIO };
++	struct sched_param start_param = { .sched_priority = 0 };
++	struct task_struct *old_stop = cpu_rq(cpu)->stop;
++
++	if (stop) {
++		/*
++		 * Make it appear like a SCHED_FIFO task, its something
++		 * userspace knows about and won't get confused about.
++		 *
++		 * Also, it will make PI more or less work without too
++		 * much confusion -- but then, stop work should not
++		 * rely on PI working anyway.
++		 */
++		sched_setscheduler_nocheck(stop, SCHED_FIFO, &stop_param);
++
++		/*
++		 * The PI code calls rt_mutex_setprio() with ->pi_lock held to
++		 * adjust the effective priority of a task. As a result,
++		 * rt_mutex_setprio() can trigger (RT) balancing operations,
++		 * which can then trigger wakeups of the stop thread to push
++		 * around the current task.
++		 *
++		 * The stop task itself will never be part of the PI-chain, it
++		 * never blocks, therefore that ->pi_lock recursion is safe.
++		 * Tell lockdep about this by placing the stop->pi_lock in its
++		 * own class.
++		 */
++		lockdep_set_class(&stop->pi_lock, &stop_pi_lock);
++	}
++
++	cpu_rq(cpu)->stop = stop;
++
++	if (old_stop) {
++		/*
++		 * Reset it back to a normal scheduling policy so that
++		 * it can die in pieces.
++		 */
++		sched_setscheduler_nocheck(old_stop, SCHED_NORMAL, &start_param);
++	}
++}
++
++static int affine_move_task(struct rq *rq, struct task_struct *p, int dest_cpu,
++			    raw_spinlock_t *lock, unsigned long irq_flags)
++{
++	/* Can the task run on the task's current CPU? If so, we're done */
++	if (!cpumask_test_cpu(task_cpu(p), &p->cpus_mask)) {
++		if (p->migration_disabled) {
++			if (likely(p->cpus_ptr != &p->cpus_mask))
++				__do_set_cpus_ptr(p, &p->cpus_mask);
++			p->migration_disabled = 0;
++			p->migration_flags |= MDF_FORCE_ENABLED;
++			/* When p is migrate_disabled, rq->lock should be held */
++			rq->nr_pinned--;
++		}
++
++		if (task_running(p) || READ_ONCE(p->__state) == TASK_WAKING) {
++			struct migration_arg arg = { p, dest_cpu };
++
++			/* Need help from migration thread: drop lock and wait. */
++			__task_access_unlock(p, lock);
++			raw_spin_unlock_irqrestore(&p->pi_lock, irq_flags);
++			stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
++			return 0;
++		}
++		if (task_on_rq_queued(p)) {
++			/*
++			 * OK, since we're going to drop the lock immediately
++			 * afterwards anyway.
++			 */
++			update_rq_clock(rq);
++			rq = move_queued_task(rq, p, dest_cpu);
++			lock = &rq->lock;
++		}
++	}
++	__task_access_unlock(p, lock);
++	raw_spin_unlock_irqrestore(&p->pi_lock, irq_flags);
++	return 0;
++}
++
++static int __set_cpus_allowed_ptr_locked(struct task_struct *p,
++					 const struct cpumask *new_mask,
++					 u32 flags,
++					 struct rq *rq,
++					 raw_spinlock_t *lock,
++					 unsigned long irq_flags)
++{
++	const struct cpumask *cpu_allowed_mask = task_cpu_possible_mask(p);
++	const struct cpumask *cpu_valid_mask = cpu_active_mask;
++	bool kthread = p->flags & PF_KTHREAD;
++	struct cpumask *user_mask = NULL;
++	int dest_cpu;
++	int ret = 0;
++
++	if (kthread || is_migration_disabled(p)) {
++		/*
++		 * Kernel threads are allowed on online && !active CPUs,
++		 * however, during cpu-hot-unplug, even these might get pushed
++		 * away if not KTHREAD_IS_PER_CPU.
++		 *
++		 * Specifically, migration_disabled() tasks must not fail the
++		 * cpumask_any_and_distribute() pick below, esp. so on
++		 * SCA_MIGRATE_ENABLE, otherwise we'll not call
++		 * set_cpus_allowed_common() and actually reset p->cpus_ptr.
++		 */
++		cpu_valid_mask = cpu_online_mask;
++	}
++
++	if (!kthread && !cpumask_subset(new_mask, cpu_allowed_mask)) {
++		ret = -EINVAL;
++		goto out;
++	}
++
++	/*
++	 * Must re-check here, to close a race against __kthread_bind(),
++	 * sched_setaffinity() is not guaranteed to observe the flag.
++	 */
++	if ((flags & SCA_CHECK) && (p->flags & PF_NO_SETAFFINITY)) {
++		ret = -EINVAL;
++		goto out;
++	}
++
++	if (cpumask_equal(&p->cpus_mask, new_mask))
++		goto out;
++
++	dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask);
++	if (dest_cpu >= nr_cpu_ids) {
++		ret = -EINVAL;
++		goto out;
++	}
++
++	__do_set_cpus_allowed(p, new_mask);
++
++	if (flags & SCA_USER)
++		user_mask = clear_user_cpus_ptr(p);
++
++	ret = affine_move_task(rq, p, dest_cpu, lock, irq_flags);
++
++	kfree(user_mask);
++
++	return ret;
++
++out:
++	__task_access_unlock(p, lock);
++	raw_spin_unlock_irqrestore(&p->pi_lock, irq_flags);
++
++	return ret;
++}
++
++/*
++ * Change a given task's CPU affinity. Migrate the thread to a
++ * proper CPU and schedule it away if the CPU it's executing on
++ * is removed from the allowed bitmask.
++ *
++ * NOTE: the caller must have a valid reference to the task, the
++ * task must not exit() & deallocate itself prematurely. The
++ * call is not atomic; no spinlocks may be held.
++ */
++static int __set_cpus_allowed_ptr(struct task_struct *p,
++				  const struct cpumask *new_mask, u32 flags)
++{
++	unsigned long irq_flags;
++	struct rq *rq;
++	raw_spinlock_t *lock;
++
++	raw_spin_lock_irqsave(&p->pi_lock, irq_flags);
++	rq = __task_access_lock(p, &lock);
++
++	return __set_cpus_allowed_ptr_locked(p, new_mask, flags, rq, lock, irq_flags);
++}
++
++int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
++{
++	return __set_cpus_allowed_ptr(p, new_mask, 0);
++}
++EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
++
++/*
++ * Change a given task's CPU affinity to the intersection of its current
++ * affinity mask and @subset_mask, writing the resulting mask to @new_mask
++ * and pointing @p->user_cpus_ptr to a copy of the old mask.
++ * If the resulting mask is empty, leave the affinity unchanged and return
++ * -EINVAL.
++ */
++static int restrict_cpus_allowed_ptr(struct task_struct *p,
++				     struct cpumask *new_mask,
++				     const struct cpumask *subset_mask)
++{
++	struct cpumask *user_mask = NULL;
++	unsigned long irq_flags;
++	raw_spinlock_t *lock;
++	struct rq *rq;
++	int err;
++
++	if (!p->user_cpus_ptr) {
++		user_mask = kmalloc(cpumask_size(), GFP_KERNEL);
++		if (!user_mask)
++			return -ENOMEM;
++	}
++
++	raw_spin_lock_irqsave(&p->pi_lock, irq_flags);
++	rq = __task_access_lock(p, &lock);
++
++	if (!cpumask_and(new_mask, &p->cpus_mask, subset_mask)) {
++		err = -EINVAL;
++		goto err_unlock;
++	}
++
++	/*
++	 * We're about to butcher the task affinity, so keep track of what
++	 * the user asked for in case we're able to restore it later on.
++	 */
++	if (user_mask) {
++		cpumask_copy(user_mask, p->cpus_ptr);
++		p->user_cpus_ptr = user_mask;
++	}
++
++	/*return __set_cpus_allowed_ptr_locked(p, new_mask, 0, rq, &rf);*/
++	return __set_cpus_allowed_ptr_locked(p, new_mask, 0, rq, lock, irq_flags);
++
++err_unlock:
++	__task_access_unlock(p, lock);
++	raw_spin_unlock_irqrestore(&p->pi_lock, irq_flags);
++	kfree(user_mask);
++	return err;
++}
++
++/*
++ * Restrict the CPU affinity of task @p so that it is a subset of
++ * task_cpu_possible_mask() and point @p->user_cpu_ptr to a copy of the
++ * old affinity mask. If the resulting mask is empty, we warn and walk
++ * up the cpuset hierarchy until we find a suitable mask.
++ */
++void force_compatible_cpus_allowed_ptr(struct task_struct *p)
++{
++	cpumask_var_t new_mask;
++	const struct cpumask *override_mask = task_cpu_possible_mask(p);
++
++	alloc_cpumask_var(&new_mask, GFP_KERNEL);
++
++	/*
++	 * __migrate_task() can fail silently in the face of concurrent
++	 * offlining of the chosen destination CPU, so take the hotplug
++	 * lock to ensure that the migration succeeds.
++	 */
++	cpus_read_lock();
++	if (!cpumask_available(new_mask))
++		goto out_set_mask;
++
++	if (!restrict_cpus_allowed_ptr(p, new_mask, override_mask))
++		goto out_free_mask;
++
++	/*
++	 * We failed to find a valid subset of the affinity mask for the
++	 * task, so override it based on its cpuset hierarchy.
++	 */
++	cpuset_cpus_allowed(p, new_mask);
++	override_mask = new_mask;
++
++out_set_mask:
++	if (printk_ratelimit()) {
++		printk_deferred("Overriding affinity for process %d (%s) to CPUs %*pbl\n",
++				task_pid_nr(p), p->comm,
++				cpumask_pr_args(override_mask));
++	}
++
++	WARN_ON(set_cpus_allowed_ptr(p, override_mask));
++out_free_mask:
++	cpus_read_unlock();
++	free_cpumask_var(new_mask);
++}
++
++static int
++__sched_setaffinity(struct task_struct *p, const struct cpumask *mask);
++
++/*
++ * Restore the affinity of a task @p which was previously restricted by a
++ * call to force_compatible_cpus_allowed_ptr(). This will clear (and free)
++ * @p->user_cpus_ptr.
++ *
++ * It is the caller's responsibility to serialise this with any calls to
++ * force_compatible_cpus_allowed_ptr(@p).
++ */
++void relax_compatible_cpus_allowed_ptr(struct task_struct *p)
++{
++	struct cpumask *user_mask = p->user_cpus_ptr;
++	unsigned long flags;
++
++	/*
++	 * Try to restore the old affinity mask. If this fails, then
++	 * we free the mask explicitly to avoid it being inherited across
++	 * a subsequent fork().
++	 */
++	if (!user_mask || !__sched_setaffinity(p, user_mask))
++		return;
++
++	raw_spin_lock_irqsave(&p->pi_lock, flags);
++	user_mask = clear_user_cpus_ptr(p);
++	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++
++	kfree(user_mask);
++}
++
++#else /* CONFIG_SMP */
++
++static inline int select_task_rq(struct task_struct *p)
++{
++	return 0;
++}
++
++static inline int
++__set_cpus_allowed_ptr(struct task_struct *p,
++		       const struct cpumask *new_mask, u32 flags)
++{
++	return set_cpus_allowed_ptr(p, new_mask);
++}
++
++static inline bool rq_has_pinned_tasks(struct rq *rq)
++{
++	return false;
++}
++
++#endif /* !CONFIG_SMP */
++
++static void
++ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
++{
++	struct rq *rq;
++
++	if (!schedstat_enabled())
++		return;
++
++	rq = this_rq();
++
++#ifdef CONFIG_SMP
++	if (cpu == rq->cpu)
++		__schedstat_inc(rq->ttwu_local);
++	else {
++		/** Alt schedule FW ToDo:
++		 * How to do ttwu_wake_remote
++		 */
++	}
++#endif /* CONFIG_SMP */
++
++	__schedstat_inc(rq->ttwu_count);
++}
++
++/*
++ * Mark the task runnable and perform wakeup-preemption.
++ */
++static inline void
++ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
++{
++	check_preempt_curr(rq);
++	WRITE_ONCE(p->__state, TASK_RUNNING);
++	trace_sched_wakeup(p);
++}
++
++static inline void
++ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
++{
++	if (p->sched_contributes_to_load)
++		rq->nr_uninterruptible--;
++
++	if (
++#ifdef CONFIG_SMP
++	    !(wake_flags & WF_MIGRATED) &&
++#endif
++	    p->in_iowait) {
++		delayacct_blkio_end(p);
++		atomic_dec(&task_rq(p)->nr_iowait);
++	}
++
++	activate_task(p, rq);
++	ttwu_do_wakeup(rq, p, 0);
++}
++
++/*
++ * Consider @p being inside a wait loop:
++ *
++ *   for (;;) {
++ *      set_current_state(TASK_UNINTERRUPTIBLE);
++ *
++ *      if (CONDITION)
++ *         break;
++ *
++ *      schedule();
++ *   }
++ *   __set_current_state(TASK_RUNNING);
++ *
++ * between set_current_state() and schedule(). In this case @p is still
++ * runnable, so all that needs doing is change p->state back to TASK_RUNNING in
++ * an atomic manner.
++ *
++ * By taking task_rq(p)->lock we serialize against schedule(), if @p->on_rq
++ * then schedule() must still happen and p->state can be changed to
++ * TASK_RUNNING. Otherwise we lost the race, schedule() has happened, and we
++ * need to do a full wakeup with enqueue.
++ *
++ * Returns: %true when the wakeup is done,
++ *          %false otherwise.
++ */
++static int ttwu_runnable(struct task_struct *p, int wake_flags)
++{
++	struct rq *rq;
++	raw_spinlock_t *lock;
++	int ret = 0;
++
++	rq = __task_access_lock(p, &lock);
++	if (task_on_rq_queued(p)) {
++		/* check_preempt_curr() may use rq clock */
++		update_rq_clock(rq);
++		ttwu_do_wakeup(rq, p, wake_flags);
++		ret = 1;
++	}
++	__task_access_unlock(p, lock);
++
++	return ret;
++}
++
++#ifdef CONFIG_SMP
++void sched_ttwu_pending(void *arg)
++{
++	struct llist_node *llist = arg;
++	struct rq *rq = this_rq();
++	struct task_struct *p, *t;
++	struct rq_flags rf;
++
++	if (!llist)
++		return;
++
++	/*
++	 * rq::ttwu_pending racy indication of out-standing wakeups.
++	 * Races such that false-negatives are possible, since they
++	 * are shorter lived that false-positives would be.
++	 */
++	WRITE_ONCE(rq->ttwu_pending, 0);
++
++	rq_lock_irqsave(rq, &rf);
++	update_rq_clock(rq);
++
++	llist_for_each_entry_safe(p, t, llist, wake_entry.llist) {
++		if (WARN_ON_ONCE(p->on_cpu))
++			smp_cond_load_acquire(&p->on_cpu, !VAL);
++
++		if (WARN_ON_ONCE(task_cpu(p) != cpu_of(rq)))
++			set_task_cpu(p, cpu_of(rq));
++
++		ttwu_do_activate(rq, p, p->sched_remote_wakeup ? WF_MIGRATED : 0);
++	}
++
++	rq_unlock_irqrestore(rq, &rf);
++}
++
++void send_call_function_single_ipi(int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++
++	if (!set_nr_if_polling(rq->idle))
++		arch_send_call_function_single_ipi(cpu);
++	else
++		trace_sched_wake_idle_without_ipi(cpu);
++}
++
++/*
++ * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
++ * necessary. The wakee CPU on receipt of the IPI will queue the task
++ * via sched_ttwu_wakeup() for activation so the wakee incurs the cost
++ * of the wakeup instead of the waker.
++ */
++static void __ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
++{
++	struct rq *rq = cpu_rq(cpu);
++
++	p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
++
++	WRITE_ONCE(rq->ttwu_pending, 1);
++	__smp_call_single_queue(cpu, &p->wake_entry.llist);
++}
++
++static inline bool ttwu_queue_cond(int cpu, int wake_flags)
++{
++	/*
++	 * Do not complicate things with the async wake_list while the CPU is
++	 * in hotplug state.
++	 */
++	if (!cpu_active(cpu))
++		return false;
++
++	/*
++	 * If the CPU does not share cache, then queue the task on the
++	 * remote rqs wakelist to avoid accessing remote data.
++	 */
++	if (!cpus_share_cache(smp_processor_id(), cpu))
++		return true;
++
++	/*
++	 * If the task is descheduling and the only running task on the
++	 * CPU then use the wakelist to offload the task activation to
++	 * the soon-to-be-idle CPU as the current CPU is likely busy.
++	 * nr_running is checked to avoid unnecessary task stacking.
++	 */
++	if ((wake_flags & WF_ON_CPU) && cpu_rq(cpu)->nr_running <= 1)
++		return true;
++
++	return false;
++}
++
++static bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
++{
++	if (__is_defined(ALT_SCHED_TTWU_QUEUE) && ttwu_queue_cond(cpu, wake_flags)) {
++		if (WARN_ON_ONCE(cpu == smp_processor_id()))
++			return false;
++
++		sched_clock_cpu(cpu); /* Sync clocks across CPUs */
++		__ttwu_queue_wakelist(p, cpu, wake_flags);
++		return true;
++	}
++
++	return false;
++}
++
++void wake_up_if_idle(int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++	unsigned long flags;
++
++	rcu_read_lock();
++
++	if (!is_idle_task(rcu_dereference(rq->curr)))
++		goto out;
++
++	if (set_nr_if_polling(rq->idle)) {
++		trace_sched_wake_idle_without_ipi(cpu);
++	} else {
++		raw_spin_lock_irqsave(&rq->lock, flags);
++		if (is_idle_task(rq->curr))
++			smp_send_reschedule(cpu);
++		/* Else CPU is not idle, do nothing here */
++		raw_spin_unlock_irqrestore(&rq->lock, flags);
++	}
++
++out:
++	rcu_read_unlock();
++}
++
++bool cpus_share_cache(int this_cpu, int that_cpu)
++{
++	return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
++}
++#else /* !CONFIG_SMP */
++
++static inline bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
++{
++	return false;
++}
++
++#endif /* CONFIG_SMP */
++
++static inline void ttwu_queue(struct task_struct *p, int cpu, int wake_flags)
++{
++	struct rq *rq = cpu_rq(cpu);
++
++	if (ttwu_queue_wakelist(p, cpu, wake_flags))
++		return;
++
++	raw_spin_lock(&rq->lock);
++	update_rq_clock(rq);
++	ttwu_do_activate(rq, p, wake_flags);
++	raw_spin_unlock(&rq->lock);
++}
++
++/*
++ * Invoked from try_to_wake_up() to check whether the task can be woken up.
++ *
++ * The caller holds p::pi_lock if p != current or has preemption
++ * disabled when p == current.
++ *
++ * The rules of PREEMPT_RT saved_state:
++ *
++ *   The related locking code always holds p::pi_lock when updating
++ *   p::saved_state, which means the code is fully serialized in both cases.
++ *
++ *   The lock wait and lock wakeups happen via TASK_RTLOCK_WAIT. No other
++ *   bits set. This allows to distinguish all wakeup scenarios.
++ */
++static __always_inline
++bool ttwu_state_match(struct task_struct *p, unsigned int state, int *success)
++{
++	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)) {
++		WARN_ON_ONCE((state & TASK_RTLOCK_WAIT) &&
++			     state != TASK_RTLOCK_WAIT);
++	}
++
++	if (READ_ONCE(p->__state) & state) {
++		*success = 1;
++		return true;
++	}
++
++#ifdef CONFIG_PREEMPT_RT
++	/*
++	 * Saved state preserves the task state across blocking on
++	 * an RT lock.  If the state matches, set p::saved_state to
++	 * TASK_RUNNING, but do not wake the task because it waits
++	 * for a lock wakeup. Also indicate success because from
++	 * the regular waker's point of view this has succeeded.
++	 *
++	 * After acquiring the lock the task will restore p::__state
++	 * from p::saved_state which ensures that the regular
++	 * wakeup is not lost. The restore will also set
++	 * p::saved_state to TASK_RUNNING so any further tests will
++	 * not result in false positives vs. @success
++	 */
++	if (p->saved_state & state) {
++		p->saved_state = TASK_RUNNING;
++		*success = 1;
++	}
++#endif
++	return false;
++}
++
++/*
++ * Notes on Program-Order guarantees on SMP systems.
++ *
++ *  MIGRATION
++ *
++ * The basic program-order guarantee on SMP systems is that when a task [t]
++ * migrates, all its activity on its old CPU [c0] happens-before any subsequent
++ * execution on its new CPU [c1].
++ *
++ * For migration (of runnable tasks) this is provided by the following means:
++ *
++ *  A) UNLOCK of the rq(c0)->lock scheduling out task t
++ *  B) migration for t is required to synchronize *both* rq(c0)->lock and
++ *     rq(c1)->lock (if not at the same time, then in that order).
++ *  C) LOCK of the rq(c1)->lock scheduling in task
++ *
++ * Transitivity guarantees that B happens after A and C after B.
++ * Note: we only require RCpc transitivity.
++ * Note: the CPU doing B need not be c0 or c1
++ *
++ * Example:
++ *
++ *   CPU0            CPU1            CPU2
++ *
++ *   LOCK rq(0)->lock
++ *   sched-out X
++ *   sched-in Y
++ *   UNLOCK rq(0)->lock
++ *
++ *                                   LOCK rq(0)->lock // orders against CPU0
++ *                                   dequeue X
++ *                                   UNLOCK rq(0)->lock
++ *
++ *                                   LOCK rq(1)->lock
++ *                                   enqueue X
++ *                                   UNLOCK rq(1)->lock
++ *
++ *                   LOCK rq(1)->lock // orders against CPU2
++ *                   sched-out Z
++ *                   sched-in X
++ *                   UNLOCK rq(1)->lock
++ *
++ *
++ *  BLOCKING -- aka. SLEEP + WAKEUP
++ *
++ * For blocking we (obviously) need to provide the same guarantee as for
++ * migration. However the means are completely different as there is no lock
++ * chain to provide order. Instead we do:
++ *
++ *   1) smp_store_release(X->on_cpu, 0)   -- finish_task()
++ *   2) smp_cond_load_acquire(!X->on_cpu) -- try_to_wake_up()
++ *
++ * Example:
++ *
++ *   CPU0 (schedule)  CPU1 (try_to_wake_up) CPU2 (schedule)
++ *
++ *   LOCK rq(0)->lock LOCK X->pi_lock
++ *   dequeue X
++ *   sched-out X
++ *   smp_store_release(X->on_cpu, 0);
++ *
++ *                    smp_cond_load_acquire(&X->on_cpu, !VAL);
++ *                    X->state = WAKING
++ *                    set_task_cpu(X,2)
++ *
++ *                    LOCK rq(2)->lock
++ *                    enqueue X
++ *                    X->state = RUNNING
++ *                    UNLOCK rq(2)->lock
++ *
++ *                                          LOCK rq(2)->lock // orders against CPU1
++ *                                          sched-out Z
++ *                                          sched-in X
++ *                                          UNLOCK rq(2)->lock
++ *
++ *                    UNLOCK X->pi_lock
++ *   UNLOCK rq(0)->lock
++ *
++ *
++ * However; for wakeups there is a second guarantee we must provide, namely we
++ * must observe the state that lead to our wakeup. That is, not only must our
++ * task observe its own prior state, it must also observe the stores prior to
++ * its wakeup.
++ *
++ * This means that any means of doing remote wakeups must order the CPU doing
++ * the wakeup against the CPU the task is going to end up running on. This,
++ * however, is already required for the regular Program-Order guarantee above,
++ * since the waking CPU is the one issueing the ACQUIRE (smp_cond_load_acquire).
++ *
++ */
++
++/**
++ * try_to_wake_up - wake up a thread
++ * @p: the thread to be awakened
++ * @state: the mask of task states that can be woken
++ * @wake_flags: wake modifier flags (WF_*)
++ *
++ * Conceptually does:
++ *
++ *   If (@state & @p->state) @p->state = TASK_RUNNING.
++ *
++ * If the task was not queued/runnable, also place it back on a runqueue.
++ *
++ * This function is atomic against schedule() which would dequeue the task.
++ *
++ * It issues a full memory barrier before accessing @p->state, see the comment
++ * with set_current_state().
++ *
++ * Uses p->pi_lock to serialize against concurrent wake-ups.
++ *
++ * Relies on p->pi_lock stabilizing:
++ *  - p->sched_class
++ *  - p->cpus_ptr
++ *  - p->sched_task_group
++ * in order to do migration, see its use of select_task_rq()/set_task_cpu().
++ *
++ * Tries really hard to only take one task_rq(p)->lock for performance.
++ * Takes rq->lock in:
++ *  - ttwu_runnable()    -- old rq, unavoidable, see comment there;
++ *  - ttwu_queue()       -- new rq, for enqueue of the task;
++ *  - psi_ttwu_dequeue() -- much sadness :-( accounting will kill us.
++ *
++ * As a consequence we race really badly with just about everything. See the
++ * many memory barriers and their comments for details.
++ *
++ * Return: %true if @p->state changes (an actual wakeup was done),
++ *	   %false otherwise.
++ */
++static int try_to_wake_up(struct task_struct *p, unsigned int state,
++			  int wake_flags)
++{
++	unsigned long flags;
++	int cpu, success = 0;
++
++	preempt_disable();
++	if (p == current) {
++		/*
++		 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
++		 * == smp_processor_id()'. Together this means we can special
++		 * case the whole 'p->on_rq && ttwu_runnable()' case below
++		 * without taking any locks.
++		 *
++		 * In particular:
++		 *  - we rely on Program-Order guarantees for all the ordering,
++		 *  - we're serialized against set_special_state() by virtue of
++		 *    it disabling IRQs (this allows not taking ->pi_lock).
++		 */
++		if (!ttwu_state_match(p, state, &success))
++			goto out;
++
++		trace_sched_waking(p);
++		WRITE_ONCE(p->__state, TASK_RUNNING);
++		trace_sched_wakeup(p);
++		goto out;
++	}
++
++	/*
++	 * If we are going to wake up a thread waiting for CONDITION we
++	 * need to ensure that CONDITION=1 done by the caller can not be
++	 * reordered with p->state check below. This pairs with smp_store_mb()
++	 * in set_current_state() that the waiting thread does.
++	 */
++	raw_spin_lock_irqsave(&p->pi_lock, flags);
++	smp_mb__after_spinlock();
++	if (!ttwu_state_match(p, state, &success))
++		goto unlock;
++
++	trace_sched_waking(p);
++
++	/*
++	 * Ensure we load p->on_rq _after_ p->state, otherwise it would
++	 * be possible to, falsely, observe p->on_rq == 0 and get stuck
++	 * in smp_cond_load_acquire() below.
++	 *
++	 * sched_ttwu_pending()			try_to_wake_up()
++	 *   STORE p->on_rq = 1			  LOAD p->state
++	 *   UNLOCK rq->lock
++	 *
++	 * __schedule() (switch to task 'p')
++	 *   LOCK rq->lock			  smp_rmb();
++	 *   smp_mb__after_spinlock();
++	 *   UNLOCK rq->lock
++	 *
++	 * [task p]
++	 *   STORE p->state = UNINTERRUPTIBLE	  LOAD p->on_rq
++	 *
++	 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
++	 * __schedule().  See the comment for smp_mb__after_spinlock().
++	 *
++	 * A similar smb_rmb() lives in try_invoke_on_locked_down_task().
++	 */
++	smp_rmb();
++	if (READ_ONCE(p->on_rq) && ttwu_runnable(p, wake_flags))
++		goto unlock;
++
++#ifdef CONFIG_SMP
++	/*
++	 * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
++	 * possible to, falsely, observe p->on_cpu == 0.
++	 *
++	 * One must be running (->on_cpu == 1) in order to remove oneself
++	 * from the runqueue.
++	 *
++	 * __schedule() (switch to task 'p')	try_to_wake_up()
++	 *   STORE p->on_cpu = 1		  LOAD p->on_rq
++	 *   UNLOCK rq->lock
++	 *
++	 * __schedule() (put 'p' to sleep)
++	 *   LOCK rq->lock			  smp_rmb();
++	 *   smp_mb__after_spinlock();
++	 *   STORE p->on_rq = 0			  LOAD p->on_cpu
++	 *
++	 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
++	 * __schedule().  See the comment for smp_mb__after_spinlock().
++	 *
++	 * Form a control-dep-acquire with p->on_rq == 0 above, to ensure
++	 * schedule()'s deactivate_task() has 'happened' and p will no longer
++	 * care about it's own p->state. See the comment in __schedule().
++	 */
++	smp_acquire__after_ctrl_dep();
++
++	/*
++	 * We're doing the wakeup (@success == 1), they did a dequeue (p->on_rq
++	 * == 0), which means we need to do an enqueue, change p->state to
++	 * TASK_WAKING such that we can unlock p->pi_lock before doing the
++	 * enqueue, such as ttwu_queue_wakelist().
++	 */
++	WRITE_ONCE(p->__state, TASK_WAKING);
++
++	/*
++	 * If the owning (remote) CPU is still in the middle of schedule() with
++	 * this task as prev, considering queueing p on the remote CPUs wake_list
++	 * which potentially sends an IPI instead of spinning on p->on_cpu to
++	 * let the waker make forward progress. This is safe because IRQs are
++	 * disabled and the IPI will deliver after on_cpu is cleared.
++	 *
++	 * Ensure we load task_cpu(p) after p->on_cpu:
++	 *
++	 * set_task_cpu(p, cpu);
++	 *   STORE p->cpu = @cpu
++	 * __schedule() (switch to task 'p')
++	 *   LOCK rq->lock
++	 *   smp_mb__after_spin_lock()          smp_cond_load_acquire(&p->on_cpu)
++	 *   STORE p->on_cpu = 1                LOAD p->cpu
++	 *
++	 * to ensure we observe the correct CPU on which the task is currently
++	 * scheduling.
++	 */
++	if (smp_load_acquire(&p->on_cpu) &&
++	    ttwu_queue_wakelist(p, task_cpu(p), wake_flags | WF_ON_CPU))
++		goto unlock;
++
++	/*
++	 * If the owning (remote) CPU is still in the middle of schedule() with
++	 * this task as prev, wait until it's done referencing the task.
++	 *
++	 * Pairs with the smp_store_release() in finish_task().
++	 *
++	 * This ensures that tasks getting woken will be fully ordered against
++	 * their previous state and preserve Program Order.
++	 */
++	smp_cond_load_acquire(&p->on_cpu, !VAL);
++
++	sched_task_ttwu(p);
++
++	cpu = select_task_rq(p);
++
++	if (cpu != task_cpu(p)) {
++		if (p->in_iowait) {
++			delayacct_blkio_end(p);
++			atomic_dec(&task_rq(p)->nr_iowait);
++		}
++
++		wake_flags |= WF_MIGRATED;
++		psi_ttwu_dequeue(p);
++		set_task_cpu(p, cpu);
++	}
++#else
++	cpu = task_cpu(p);
++#endif /* CONFIG_SMP */
++
++	ttwu_queue(p, cpu, wake_flags);
++unlock:
++	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++out:
++	if (success)
++		ttwu_stat(p, task_cpu(p), wake_flags);
++	preempt_enable();
++
++	return success;
++}
++
++/**
++ * try_invoke_on_locked_down_task - Invoke a function on task in fixed state
++ * @p: Process for which the function is to be invoked, can be @current.
++ * @func: Function to invoke.
++ * @arg: Argument to function.
++ *
++ * If the specified task can be quickly locked into a definite state
++ * (either sleeping or on a given runqueue), arrange to keep it in that
++ * state while invoking @func(@arg).  This function can use ->on_rq and
++ * task_curr() to work out what the state is, if required.  Given that
++ * @func can be invoked with a runqueue lock held, it had better be quite
++ * lightweight.
++ *
++ * Returns:
++ *	@false if the task slipped out from under the locks.
++ *	@true if the task was locked onto a runqueue or is sleeping.
++ *		However, @func can override this by returning @false.
++ */
++bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg)
++{
++	struct rq_flags rf;
++	bool ret = false;
++	struct rq *rq;
++
++	raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
++	if (p->on_rq) {
++		rq = __task_rq_lock(p, &rf);
++		if (task_rq(p) == rq)
++			ret = func(p, arg);
++		__task_rq_unlock(rq, &rf);
++	} else {
++		switch (READ_ONCE(p->__state)) {
++		case TASK_RUNNING:
++		case TASK_WAKING:
++			break;
++		default:
++			smp_rmb(); // See smp_rmb() comment in try_to_wake_up().
++			if (!p->on_rq)
++				ret = func(p, arg);
++		}
++	}
++	raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
++	return ret;
++}
++
++/**
++ * wake_up_process - Wake up a specific process
++ * @p: The process to be woken up.
++ *
++ * Attempt to wake up the nominated process and move it to the set of runnable
++ * processes.
++ *
++ * Return: 1 if the process was woken up, 0 if it was already running.
++ *
++ * This function executes a full memory barrier before accessing the task state.
++ */
++int wake_up_process(struct task_struct *p)
++{
++	return try_to_wake_up(p, TASK_NORMAL, 0);
++}
++EXPORT_SYMBOL(wake_up_process);
++
++int wake_up_state(struct task_struct *p, unsigned int state)
++{
++	return try_to_wake_up(p, state, 0);
++}
++
++/*
++ * Perform scheduler related setup for a newly forked process p.
++ * p is forked by current.
++ *
++ * __sched_fork() is basic setup used by init_idle() too:
++ */
++static inline void __sched_fork(unsigned long clone_flags, struct task_struct *p)
++{
++	p->on_rq			= 0;
++	p->on_cpu			= 0;
++	p->utime			= 0;
++	p->stime			= 0;
++	p->sched_time			= 0;
++
++#ifdef CONFIG_PREEMPT_NOTIFIERS
++	INIT_HLIST_HEAD(&p->preempt_notifiers);
++#endif
++
++#ifdef CONFIG_COMPACTION
++	p->capture_control = NULL;
++#endif
++#ifdef CONFIG_SMP
++	p->wake_entry.u_flags = CSD_TYPE_TTWU;
++#endif
++}
++
++/*
++ * fork()/clone()-time setup:
++ */
++int sched_fork(unsigned long clone_flags, struct task_struct *p)
++{
++	unsigned long flags;
++	struct rq *rq;
++
++	__sched_fork(clone_flags, p);
++	/*
++	 * We mark the process as NEW here. This guarantees that
++	 * nobody will actually run it, and a signal or other external
++	 * event cannot wake it up and insert it on the runqueue either.
++	 */
++	p->__state = TASK_NEW;
++
++	/*
++	 * Make sure we do not leak PI boosting priority to the child.
++	 */
++	p->prio = current->normal_prio;
++
++	/*
++	 * Revert to default priority/policy on fork if requested.
++	 */
++	if (unlikely(p->sched_reset_on_fork)) {
++		if (task_has_rt_policy(p)) {
++			p->policy = SCHED_NORMAL;
++			p->static_prio = NICE_TO_PRIO(0);
++			p->rt_priority = 0;
++		} else if (PRIO_TO_NICE(p->static_prio) < 0)
++			p->static_prio = NICE_TO_PRIO(0);
++
++		p->prio = p->normal_prio = p->static_prio;
++
++		/*
++		 * We don't need the reset flag anymore after the fork. It has
++		 * fulfilled its duty:
++		 */
++		p->sched_reset_on_fork = 0;
++	}
++
++	/*
++	 * The child is not yet in the pid-hash so no cgroup attach races,
++	 * and the cgroup is pinned to this child due to cgroup_fork()
++	 * is ran before sched_fork().
++	 *
++	 * Silence PROVE_RCU.
++	 */
++	raw_spin_lock_irqsave(&p->pi_lock, flags);
++	/*
++	 * Share the timeslice between parent and child, thus the
++	 * total amount of pending timeslices in the system doesn't change,
++	 * resulting in more scheduling fairness.
++	 */
++	rq = this_rq();
++	raw_spin_lock(&rq->lock);
++
++	rq->curr->time_slice /= 2;
++	p->time_slice = rq->curr->time_slice;
++#ifdef CONFIG_SCHED_HRTICK
++	hrtick_start(rq, rq->curr->time_slice);
++#endif
++
++	if (p->time_slice < RESCHED_NS) {
++		p->time_slice = sched_timeslice_ns;
++		resched_curr(rq);
++	}
++	sched_task_fork(p, rq);
++	raw_spin_unlock(&rq->lock);
++
++	rseq_migrate(p);
++	/*
++	 * We're setting the CPU for the first time, we don't migrate,
++	 * so use __set_task_cpu().
++	 */
++	__set_task_cpu(p, cpu_of(rq));
++	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++
++#ifdef CONFIG_SCHED_INFO
++	if (unlikely(sched_info_on()))
++		memset(&p->sched_info, 0, sizeof(p->sched_info));
++#endif
++	init_task_preempt_count(p);
++
++	return 0;
++}
++
++void sched_post_fork(struct task_struct *p) {}
++
++#ifdef CONFIG_SCHEDSTATS
++
++DEFINE_STATIC_KEY_FALSE(sched_schedstats);
++
++static void set_schedstats(bool enabled)
++{
++	if (enabled)
++		static_branch_enable(&sched_schedstats);
++	else
++		static_branch_disable(&sched_schedstats);
++}
++
++void force_schedstat_enabled(void)
++{
++	if (!schedstat_enabled()) {
++		pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n");
++		static_branch_enable(&sched_schedstats);
++	}
++}
++
++static int __init setup_schedstats(char *str)
++{
++	int ret = 0;
++	if (!str)
++		goto out;
++
++	if (!strcmp(str, "enable")) {
++		set_schedstats(true);
++		ret = 1;
++	} else if (!strcmp(str, "disable")) {
++		set_schedstats(false);
++		ret = 1;
++	}
++out:
++	if (!ret)
++		pr_warn("Unable to parse schedstats=\n");
++
++	return ret;
++}
++__setup("schedstats=", setup_schedstats);
++
++#ifdef CONFIG_PROC_SYSCTL
++int sysctl_schedstats(struct ctl_table *table, int write,
++			 void __user *buffer, size_t *lenp, loff_t *ppos)
++{
++	struct ctl_table t;
++	int err;
++	int state = static_branch_likely(&sched_schedstats);
++
++	if (write && !capable(CAP_SYS_ADMIN))
++		return -EPERM;
++
++	t = *table;
++	t.data = &state;
++	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
++	if (err < 0)
++		return err;
++	if (write)
++		set_schedstats(state);
++	return err;
++}
++#endif /* CONFIG_PROC_SYSCTL */
++#endif /* CONFIG_SCHEDSTATS */
++
++/*
++ * wake_up_new_task - wake up a newly created task for the first time.
++ *
++ * This function will do some initial scheduler statistics housekeeping
++ * that must be done for every newly created context, then puts the task
++ * on the runqueue and wakes it.
++ */
++void wake_up_new_task(struct task_struct *p)
++{
++	unsigned long flags;
++	struct rq *rq;
++
++	raw_spin_lock_irqsave(&p->pi_lock, flags);
++	WRITE_ONCE(p->__state, TASK_RUNNING);
++	rq = cpu_rq(select_task_rq(p));
++#ifdef CONFIG_SMP
++	rseq_migrate(p);
++	/*
++	 * Fork balancing, do it here and not earlier because:
++	 * - cpus_ptr can change in the fork path
++	 * - any previously selected CPU might disappear through hotplug
++	 *
++	 * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq,
++	 * as we're not fully set-up yet.
++	 */
++	__set_task_cpu(p, cpu_of(rq));
++#endif
++
++	raw_spin_lock(&rq->lock);
++	update_rq_clock(rq);
++
++	activate_task(p, rq);
++	trace_sched_wakeup_new(p);
++	check_preempt_curr(rq);
++
++	raw_spin_unlock(&rq->lock);
++	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++}
++
++#ifdef CONFIG_PREEMPT_NOTIFIERS
++
++static DEFINE_STATIC_KEY_FALSE(preempt_notifier_key);
++
++void preempt_notifier_inc(void)
++{
++	static_branch_inc(&preempt_notifier_key);
++}
++EXPORT_SYMBOL_GPL(preempt_notifier_inc);
++
++void preempt_notifier_dec(void)
++{
++	static_branch_dec(&preempt_notifier_key);
++}
++EXPORT_SYMBOL_GPL(preempt_notifier_dec);
++
++/**
++ * preempt_notifier_register - tell me when current is being preempted & rescheduled
++ * @notifier: notifier struct to register
++ */
++void preempt_notifier_register(struct preempt_notifier *notifier)
++{
++	if (!static_branch_unlikely(&preempt_notifier_key))
++		WARN(1, "registering preempt_notifier while notifiers disabled\n");
++
++	hlist_add_head(&notifier->link, &current->preempt_notifiers);
++}
++EXPORT_SYMBOL_GPL(preempt_notifier_register);
++
++/**
++ * preempt_notifier_unregister - no longer interested in preemption notifications
++ * @notifier: notifier struct to unregister
++ *
++ * This is *not* safe to call from within a preemption notifier.
++ */
++void preempt_notifier_unregister(struct preempt_notifier *notifier)
++{
++	hlist_del(&notifier->link);
++}
++EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
++
++static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)
++{
++	struct preempt_notifier *notifier;
++
++	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
++		notifier->ops->sched_in(notifier, raw_smp_processor_id());
++}
++
++static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
++{
++	if (static_branch_unlikely(&preempt_notifier_key))
++		__fire_sched_in_preempt_notifiers(curr);
++}
++
++static void
++__fire_sched_out_preempt_notifiers(struct task_struct *curr,
++				   struct task_struct *next)
++{
++	struct preempt_notifier *notifier;
++
++	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
++		notifier->ops->sched_out(notifier, next);
++}
++
++static __always_inline void
++fire_sched_out_preempt_notifiers(struct task_struct *curr,
++				 struct task_struct *next)
++{
++	if (static_branch_unlikely(&preempt_notifier_key))
++		__fire_sched_out_preempt_notifiers(curr, next);
++}
++
++#else /* !CONFIG_PREEMPT_NOTIFIERS */
++
++static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
++{
++}
++
++static inline void
++fire_sched_out_preempt_notifiers(struct task_struct *curr,
++				 struct task_struct *next)
++{
++}
++
++#endif /* CONFIG_PREEMPT_NOTIFIERS */
++
++static inline void prepare_task(struct task_struct *next)
++{
++	/*
++	 * Claim the task as running, we do this before switching to it
++	 * such that any running task will have this set.
++	 *
++	 * See the ttwu() WF_ON_CPU case and its ordering comment.
++	 */
++	WRITE_ONCE(next->on_cpu, 1);
++}
++
++static inline void finish_task(struct task_struct *prev)
++{
++#ifdef CONFIG_SMP
++	/*
++	 * This must be the very last reference to @prev from this CPU. After
++	 * p->on_cpu is cleared, the task can be moved to a different CPU. We
++	 * must ensure this doesn't happen until the switch is completely
++	 * finished.
++	 *
++	 * In particular, the load of prev->state in finish_task_switch() must
++	 * happen before this.
++	 *
++	 * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
++	 */
++	smp_store_release(&prev->on_cpu, 0);
++#else
++	prev->on_cpu = 0;
++#endif
++}
++
++#ifdef CONFIG_SMP
++
++static void do_balance_callbacks(struct rq *rq, struct callback_head *head)
++{
++	void (*func)(struct rq *rq);
++	struct callback_head *next;
++
++	lockdep_assert_held(&rq->lock);
++
++	while (head) {
++		func = (void (*)(struct rq *))head->func;
++		next = head->next;
++		head->next = NULL;
++		head = next;
++
++		func(rq);
++	}
++}
++
++static void balance_push(struct rq *rq);
++
++struct callback_head balance_push_callback = {
++	.next = NULL,
++	.func = (void (*)(struct callback_head *))balance_push,
++};
++
++static inline struct callback_head *splice_balance_callbacks(struct rq *rq)
++{
++	struct callback_head *head = rq->balance_callback;
++
++	if (head) {
++		lockdep_assert_held(&rq->lock);
++		rq->balance_callback = NULL;
++	}
++
++	return head;
++}
++
++static void __balance_callbacks(struct rq *rq)
++{
++	do_balance_callbacks(rq, splice_balance_callbacks(rq));
++}
++
++static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
++{
++	unsigned long flags;
++
++	if (unlikely(head)) {
++		raw_spin_lock_irqsave(&rq->lock, flags);
++		do_balance_callbacks(rq, head);
++		raw_spin_unlock_irqrestore(&rq->lock, flags);
++	}
++}
++
++#else
++
++static inline void __balance_callbacks(struct rq *rq)
++{
++}
++
++static inline struct callback_head *splice_balance_callbacks(struct rq *rq)
++{
++	return NULL;
++}
++
++static inline void balance_callbacks(struct rq *rq, struct callback_head *head)
++{
++}
++
++#endif
++
++static inline void
++prepare_lock_switch(struct rq *rq, struct task_struct *next)
++{
++	/*
++	 * Since the runqueue lock will be released by the next
++	 * task (which is an invalid locking op but in the case
++	 * of the scheduler it's an obvious special-case), so we
++	 * do an early lockdep release here:
++	 */
++	spin_release(&rq->lock.dep_map, _THIS_IP_);
++#ifdef CONFIG_DEBUG_SPINLOCK
++	/* this is a valid case when another task releases the spinlock */
++	rq->lock.owner = next;
++#endif
++}
++
++static inline void finish_lock_switch(struct rq *rq)
++{
++	/*
++	 * If we are tracking spinlock dependencies then we have to
++	 * fix up the runqueue lock - which gets 'carried over' from
++	 * prev into current:
++	 */
++	spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
++	__balance_callbacks(rq);
++	raw_spin_unlock_irq(&rq->lock);
++}
++
++/*
++ * NOP if the arch has not defined these:
++ */
++
++#ifndef prepare_arch_switch
++# define prepare_arch_switch(next)	do { } while (0)
++#endif
++
++#ifndef finish_arch_post_lock_switch
++# define finish_arch_post_lock_switch()	do { } while (0)
++#endif
++
++static inline void kmap_local_sched_out(void)
++{
++#ifdef CONFIG_KMAP_LOCAL
++	if (unlikely(current->kmap_ctrl.idx))
++		__kmap_local_sched_out();
++#endif
++}
++
++static inline void kmap_local_sched_in(void)
++{
++#ifdef CONFIG_KMAP_LOCAL
++	if (unlikely(current->kmap_ctrl.idx))
++		__kmap_local_sched_in();
++#endif
++}
++
++/**
++ * prepare_task_switch - prepare to switch tasks
++ * @rq: the runqueue preparing to switch
++ * @next: the task we are going to switch to.
++ *
++ * This is called with the rq lock held and interrupts off. It must
++ * be paired with a subsequent finish_task_switch after the context
++ * switch.
++ *
++ * prepare_task_switch sets up locking and calls architecture specific
++ * hooks.
++ */
++static inline void
++prepare_task_switch(struct rq *rq, struct task_struct *prev,
++		    struct task_struct *next)
++{
++	kcov_prepare_switch(prev);
++	sched_info_switch(rq, prev, next);
++	perf_event_task_sched_out(prev, next);
++	rseq_preempt(prev);
++	fire_sched_out_preempt_notifiers(prev, next);
++	kmap_local_sched_out();
++	prepare_task(next);
++	prepare_arch_switch(next);
++}
++
++/**
++ * finish_task_switch - clean up after a task-switch
++ * @rq: runqueue associated with task-switch
++ * @prev: the thread we just switched away from.
++ *
++ * finish_task_switch must be called after the context switch, paired
++ * with a prepare_task_switch call before the context switch.
++ * finish_task_switch will reconcile locking set up by prepare_task_switch,
++ * and do any other architecture-specific cleanup actions.
++ *
++ * Note that we may have delayed dropping an mm in context_switch(). If
++ * so, we finish that here outside of the runqueue lock.  (Doing it
++ * with the lock held can cause deadlocks; see schedule() for
++ * details.)
++ *
++ * The context switch have flipped the stack from under us and restored the
++ * local variables which were saved when this task called schedule() in the
++ * past. prev == current is still correct but we need to recalculate this_rq
++ * because prev may have moved to another CPU.
++ */
++static struct rq *finish_task_switch(struct task_struct *prev)
++	__releases(rq->lock)
++{
++	struct rq *rq = this_rq();
++	struct mm_struct *mm = rq->prev_mm;
++	long prev_state;
++
++	/*
++	 * The previous task will have left us with a preempt_count of 2
++	 * because it left us after:
++	 *
++	 *	schedule()
++	 *	  preempt_disable();			// 1
++	 *	  __schedule()
++	 *	    raw_spin_lock_irq(&rq->lock)	// 2
++	 *
++	 * Also, see FORK_PREEMPT_COUNT.
++	 */
++	if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
++		      "corrupted preempt_count: %s/%d/0x%x\n",
++		      current->comm, current->pid, preempt_count()))
++		preempt_count_set(FORK_PREEMPT_COUNT);
++
++	rq->prev_mm = NULL;
++
++	/*
++	 * A task struct has one reference for the use as "current".
++	 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
++	 * schedule one last time. The schedule call will never return, and
++	 * the scheduled task must drop that reference.
++	 *
++	 * We must observe prev->state before clearing prev->on_cpu (in
++	 * finish_task), otherwise a concurrent wakeup can get prev
++	 * running on another CPU and we could rave with its RUNNING -> DEAD
++	 * transition, resulting in a double drop.
++	 */
++	prev_state = READ_ONCE(prev->__state);
++	vtime_task_switch(prev);
++	perf_event_task_sched_in(prev, current);
++	finish_task(prev);
++	tick_nohz_task_switch();
++	finish_lock_switch(rq);
++	finish_arch_post_lock_switch();
++	kcov_finish_switch(current);
++	/*
++	 * kmap_local_sched_out() is invoked with rq::lock held and
++	 * interrupts disabled. There is no requirement for that, but the
++	 * sched out code does not have an interrupt enabled section.
++	 * Restoring the maps on sched in does not require interrupts being
++	 * disabled either.
++	 */
++	kmap_local_sched_in();
++
++	fire_sched_in_preempt_notifiers(current);
++	/*
++	 * When switching through a kernel thread, the loop in
++	 * membarrier_{private,global}_expedited() may have observed that
++	 * kernel thread and not issued an IPI. It is therefore possible to
++	 * schedule between user->kernel->user threads without passing though
++	 * switch_mm(). Membarrier requires a barrier after storing to
++	 * rq->curr, before returning to userspace, so provide them here:
++	 *
++	 * - a full memory barrier for {PRIVATE,GLOBAL}_EXPEDITED, implicitly
++	 *   provided by mmdrop(),
++	 * - a sync_core for SYNC_CORE.
++	 */
++	if (mm) {
++		membarrier_mm_sync_core_before_usermode(mm);
++		mmdrop(mm);
++	}
++	if (unlikely(prev_state == TASK_DEAD)) {
++		/*
++		 * Remove function-return probe instances associated with this
++		 * task and put them back on the free list.
++		 */
++		kprobe_flush_task(prev);
++
++		/* Task is done with its stack. */
++		put_task_stack(prev);
++
++		put_task_struct_rcu_user(prev);
++	}
++
++	return rq;
++}
++
++/**
++ * schedule_tail - first thing a freshly forked thread must call.
++ * @prev: the thread we just switched away from.
++ */
++asmlinkage __visible void schedule_tail(struct task_struct *prev)
++	__releases(rq->lock)
++{
++	/*
++	 * New tasks start with FORK_PREEMPT_COUNT, see there and
++	 * finish_task_switch() for details.
++	 *
++	 * finish_task_switch() will drop rq->lock() and lower preempt_count
++	 * and the preempt_enable() will end up enabling preemption (on
++	 * PREEMPT_COUNT kernels).
++	 */
++
++	finish_task_switch(prev);
++	preempt_enable();
++
++	if (current->set_child_tid)
++		put_user(task_pid_vnr(current), current->set_child_tid);
++
++	calculate_sigpending();
++}
++
++/*
++ * context_switch - switch to the new MM and the new thread's register state.
++ */
++static __always_inline struct rq *
++context_switch(struct rq *rq, struct task_struct *prev,
++	       struct task_struct *next)
++{
++	prepare_task_switch(rq, prev, next);
++
++	/*
++	 * For paravirt, this is coupled with an exit in switch_to to
++	 * combine the page table reload and the switch backend into
++	 * one hypercall.
++	 */
++	arch_start_context_switch(prev);
++
++	/*
++	 * kernel -> kernel   lazy + transfer active
++	 *   user -> kernel   lazy + mmgrab() active
++	 *
++	 * kernel ->   user   switch + mmdrop() active
++	 *   user ->   user   switch
++	 */
++	if (!next->mm) {                                // to kernel
++		enter_lazy_tlb(prev->active_mm, next);
++
++		next->active_mm = prev->active_mm;
++		if (prev->mm)                           // from user
++			mmgrab(prev->active_mm);
++		else
++			prev->active_mm = NULL;
++	} else {                                        // to user
++		membarrier_switch_mm(rq, prev->active_mm, next->mm);
++		/*
++		 * sys_membarrier() requires an smp_mb() between setting
++		 * rq->curr / membarrier_switch_mm() and returning to userspace.
++		 *
++		 * The below provides this either through switch_mm(), or in
++		 * case 'prev->active_mm == next->mm' through
++		 * finish_task_switch()'s mmdrop().
++		 */
++		switch_mm_irqs_off(prev->active_mm, next->mm, next);
++
++		if (!prev->mm) {                        // from kernel
++			/* will mmdrop() in finish_task_switch(). */
++			rq->prev_mm = prev->active_mm;
++			prev->active_mm = NULL;
++		}
++	}
++
++	prepare_lock_switch(rq, next);
++
++	/* Here we just switch the register state and the stack. */
++	switch_to(prev, next, prev);
++	barrier();
++
++	return finish_task_switch(prev);
++}
++
++/*
++ * nr_running, nr_uninterruptible and nr_context_switches:
++ *
++ * externally visible scheduler statistics: current number of runnable
++ * threads, total number of context switches performed since bootup.
++ */
++unsigned int nr_running(void)
++{
++	unsigned int i, sum = 0;
++
++	for_each_online_cpu(i)
++		sum += cpu_rq(i)->nr_running;
++
++	return sum;
++}
++
++/*
++ * Check if only the current task is running on the CPU.
++ *
++ * Caution: this function does not check that the caller has disabled
++ * preemption, thus the result might have a time-of-check-to-time-of-use
++ * race.  The caller is responsible to use it correctly, for example:
++ *
++ * - from a non-preemptible section (of course)
++ *
++ * - from a thread that is bound to a single CPU
++ *
++ * - in a loop with very short iterations (e.g. a polling loop)
++ */
++bool single_task_running(void)
++{
++	return raw_rq()->nr_running == 1;
++}
++EXPORT_SYMBOL(single_task_running);
++
++unsigned long long nr_context_switches(void)
++{
++	int i;
++	unsigned long long sum = 0;
++
++	for_each_possible_cpu(i)
++		sum += cpu_rq(i)->nr_switches;
++
++	return sum;
++}
++
++/*
++ * Consumers of these two interfaces, like for example the cpuidle menu
++ * governor, are using nonsensical data. Preferring shallow idle state selection
++ * for a CPU that has IO-wait which might not even end up running the task when
++ * it does become runnable.
++ */
++
++unsigned int nr_iowait_cpu(int cpu)
++{
++	return atomic_read(&cpu_rq(cpu)->nr_iowait);
++}
++
++/*
++ * IO-wait accounting, and how it's mostly bollocks (on SMP).
++ *
++ * The idea behind IO-wait account is to account the idle time that we could
++ * have spend running if it were not for IO. That is, if we were to improve the
++ * storage performance, we'd have a proportional reduction in IO-wait time.
++ *
++ * This all works nicely on UP, where, when a task blocks on IO, we account
++ * idle time as IO-wait, because if the storage were faster, it could've been
++ * running and we'd not be idle.
++ *
++ * This has been extended to SMP, by doing the same for each CPU. This however
++ * is broken.
++ *
++ * Imagine for instance the case where two tasks block on one CPU, only the one
++ * CPU will have IO-wait accounted, while the other has regular idle. Even
++ * though, if the storage were faster, both could've ran at the same time,
++ * utilising both CPUs.
++ *
++ * This means, that when looking globally, the current IO-wait accounting on
++ * SMP is a lower bound, by reason of under accounting.
++ *
++ * Worse, since the numbers are provided per CPU, they are sometimes
++ * interpreted per CPU, and that is nonsensical. A blocked task isn't strictly
++ * associated with any one particular CPU, it can wake to another CPU than it
++ * blocked on. This means the per CPU IO-wait number is meaningless.
++ *
++ * Task CPU affinities can make all that even more 'interesting'.
++ */
++
++unsigned int nr_iowait(void)
++{
++	unsigned int i, sum = 0;
++
++	for_each_possible_cpu(i)
++		sum += nr_iowait_cpu(i);
++
++	return sum;
++}
++
++#ifdef CONFIG_SMP
++
++/*
++ * sched_exec - execve() is a valuable balancing opportunity, because at
++ * this point the task has the smallest effective memory and cache
++ * footprint.
++ */
++void sched_exec(void)
++{
++	struct task_struct *p = current;
++	unsigned long flags;
++	int dest_cpu;
++
++	raw_spin_lock_irqsave(&p->pi_lock, flags);
++	dest_cpu = cpumask_any(p->cpus_ptr);
++	if (dest_cpu == smp_processor_id())
++		goto unlock;
++
++	if (likely(cpu_active(dest_cpu))) {
++		struct migration_arg arg = { p, dest_cpu };
++
++		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++		stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
++		return;
++	}
++unlock:
++	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++}
++
++#endif
++
++DEFINE_PER_CPU(struct kernel_stat, kstat);
++DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
++
++EXPORT_PER_CPU_SYMBOL(kstat);
++EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
++
++static inline void update_curr(struct rq *rq, struct task_struct *p)
++{
++	s64 ns = rq->clock_task - p->last_ran;
++
++	p->sched_time += ns;
++	cgroup_account_cputime(p, ns);
++	account_group_exec_runtime(p, ns);
++
++	p->time_slice -= ns;
++	p->last_ran = rq->clock_task;
++}
++
++/*
++ * Return accounted runtime for the task.
++ * Return separately the current's pending runtime that have not been
++ * accounted yet.
++ */
++unsigned long long task_sched_runtime(struct task_struct *p)
++{
++	unsigned long flags;
++	struct rq *rq;
++	raw_spinlock_t *lock;
++	u64 ns;
++
++#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
++	/*
++	 * 64-bit doesn't need locks to atomically read a 64-bit value.
++	 * So we have a optimization chance when the task's delta_exec is 0.
++	 * Reading ->on_cpu is racy, but this is ok.
++	 *
++	 * If we race with it leaving CPU, we'll take a lock. So we're correct.
++	 * If we race with it entering CPU, unaccounted time is 0. This is
++	 * indistinguishable from the read occurring a few cycles earlier.
++	 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
++	 * been accounted, so we're correct here as well.
++	 */
++	if (!p->on_cpu || !task_on_rq_queued(p))
++		return tsk_seruntime(p);
++#endif
++
++	rq = task_access_lock_irqsave(p, &lock, &flags);
++	/*
++	 * Must be ->curr _and_ ->on_rq.  If dequeued, we would
++	 * project cycles that may never be accounted to this
++	 * thread, breaking clock_gettime().
++	 */
++	if (p == rq->curr && task_on_rq_queued(p)) {
++		update_rq_clock(rq);
++		update_curr(rq, p);
++	}
++	ns = tsk_seruntime(p);
++	task_access_unlock_irqrestore(p, lock, &flags);
++
++	return ns;
++}
++
++/* This manages tasks that have run out of timeslice during a scheduler_tick */
++static inline void scheduler_task_tick(struct rq *rq)
++{
++	struct task_struct *p = rq->curr;
++
++	if (is_idle_task(p))
++		return;
++
++	update_curr(rq, p);
++	cpufreq_update_util(rq, 0);
++
++	/*
++	 * Tasks have less than RESCHED_NS of time slice left they will be
++	 * rescheduled.
++	 */
++	if (p->time_slice >= RESCHED_NS)
++		return;
++	set_tsk_need_resched(p);
++	set_preempt_need_resched();
++}
++
++#ifdef CONFIG_SCHED_DEBUG
++static u64 cpu_resched_latency(struct rq *rq)
++{
++	int latency_warn_ms = READ_ONCE(sysctl_resched_latency_warn_ms);
++	u64 resched_latency, now = rq_clock(rq);
++	static bool warned_once;
++
++	if (sysctl_resched_latency_warn_once && warned_once)
++		return 0;
++
++	if (!need_resched() || !latency_warn_ms)
++		return 0;
++
++	if (system_state == SYSTEM_BOOTING)
++		return 0;
++
++	if (!rq->last_seen_need_resched_ns) {
++		rq->last_seen_need_resched_ns = now;
++		rq->ticks_without_resched = 0;
++		return 0;
++	}
++
++	rq->ticks_without_resched++;
++	resched_latency = now - rq->last_seen_need_resched_ns;
++	if (resched_latency <= latency_warn_ms * NSEC_PER_MSEC)
++		return 0;
++
++	warned_once = true;
++
++	return resched_latency;
++}
++
++static int __init setup_resched_latency_warn_ms(char *str)
++{
++	long val;
++
++	if ((kstrtol(str, 0, &val))) {
++		pr_warn("Unable to set resched_latency_warn_ms\n");
++		return 1;
++	}
++
++	sysctl_resched_latency_warn_ms = val;
++	return 1;
++}
++__setup("resched_latency_warn_ms=", setup_resched_latency_warn_ms);
++#else
++static inline u64 cpu_resched_latency(struct rq *rq) { return 0; }
++#endif /* CONFIG_SCHED_DEBUG */
++
++/*
++ * This function gets called by the timer code, with HZ frequency.
++ * We call it with interrupts disabled.
++ */
++void scheduler_tick(void)
++{
++	int cpu __maybe_unused = smp_processor_id();
++	struct rq *rq = cpu_rq(cpu);
++	u64 resched_latency;
++
++	arch_scale_freq_tick();
++	sched_clock_tick();
++
++	raw_spin_lock(&rq->lock);
++	update_rq_clock(rq);
++
++	scheduler_task_tick(rq);
++	if (sched_feat(LATENCY_WARN))
++		resched_latency = cpu_resched_latency(rq);
++	calc_global_load_tick(rq);
++
++	rq->last_tick = rq->clock;
++	raw_spin_unlock(&rq->lock);
++
++	if (sched_feat(LATENCY_WARN) && resched_latency)
++		resched_latency_warn(cpu, resched_latency);
++
++	perf_event_task_tick();
++}
++
++#ifdef CONFIG_SCHED_SMT
++static inline int active_load_balance_cpu_stop(void *data)
++{
++	struct rq *rq = this_rq();
++	struct task_struct *p = data;
++	cpumask_t tmp;
++	unsigned long flags;
++
++	local_irq_save(flags);
++
++	raw_spin_lock(&p->pi_lock);
++	raw_spin_lock(&rq->lock);
++
++	rq->active_balance = 0;
++	/* _something_ may have changed the task, double check again */
++	if (task_on_rq_queued(p) && task_rq(p) == rq &&
++	    cpumask_and(&tmp, p->cpus_ptr, &sched_sg_idle_mask) &&
++	    !is_migration_disabled(p)) {
++		int cpu = cpu_of(rq);
++		int dcpu = __best_mask_cpu(&tmp, per_cpu(sched_cpu_llc_mask, cpu));
++		rq = move_queued_task(rq, p, dcpu);
++	}
++
++	raw_spin_unlock(&rq->lock);
++	raw_spin_unlock(&p->pi_lock);
++
++	local_irq_restore(flags);
++
++	return 0;
++}
++
++/* sg_balance_trigger - trigger slibing group balance for @cpu */
++static inline int sg_balance_trigger(const int cpu)
++{
++	struct rq *rq= cpu_rq(cpu);
++	unsigned long flags;
++	struct task_struct *curr;
++	int res;
++
++	if (!raw_spin_trylock_irqsave(&rq->lock, flags))
++		return 0;
++	curr = rq->curr;
++	res = (!is_idle_task(curr)) && (1 == rq->nr_running) &&\
++	      cpumask_intersects(curr->cpus_ptr, &sched_sg_idle_mask) &&\
++	      !is_migration_disabled(curr) && (!rq->active_balance);
++
++	if (res)
++		rq->active_balance = 1;
++
++	raw_spin_unlock_irqrestore(&rq->lock, flags);
++
++	if (res)
++		stop_one_cpu_nowait(cpu, active_load_balance_cpu_stop,
++				    curr, &rq->active_balance_work);
++	return res;
++}
++
++/*
++ * sg_balance_check - slibing group balance check for run queue @rq
++ */
++static inline void sg_balance_check(struct rq *rq)
++{
++	cpumask_t chk;
++	int cpu = cpu_of(rq);
++
++	/* exit when cpu is offline */
++	if (unlikely(!rq->online))
++		return;
++
++	/*
++	 * Only cpu in slibing idle group will do the checking and then
++	 * find potential cpus which can migrate the current running task
++	 */
++	if (cpumask_test_cpu(cpu, &sched_sg_idle_mask) &&
++	    cpumask_andnot(&chk, cpu_online_mask, sched_rq_watermark) &&
++	    cpumask_andnot(&chk, &chk, &sched_rq_pending_mask)) {
++		int i;
++
++		for_each_cpu_wrap(i, &chk, cpu) {
++			if (cpumask_subset(cpu_smt_mask(i), &chk) &&
++			    sg_balance_trigger(i))
++				return;
++		}
++	}
++}
++#endif /* CONFIG_SCHED_SMT */
++
++#ifdef CONFIG_NO_HZ_FULL
++
++struct tick_work {
++	int			cpu;
++	atomic_t		state;
++	struct delayed_work	work;
++};
++/* Values for ->state, see diagram below. */
++#define TICK_SCHED_REMOTE_OFFLINE	0
++#define TICK_SCHED_REMOTE_OFFLINING	1
++#define TICK_SCHED_REMOTE_RUNNING	2
++
++/*
++ * State diagram for ->state:
++ *
++ *
++ *          TICK_SCHED_REMOTE_OFFLINE
++ *                    |   ^
++ *                    |   |
++ *                    |   | sched_tick_remote()
++ *                    |   |
++ *                    |   |
++ *                    +--TICK_SCHED_REMOTE_OFFLINING
++ *                    |   ^
++ *                    |   |
++ * sched_tick_start() |   | sched_tick_stop()
++ *                    |   |
++ *                    V   |
++ *          TICK_SCHED_REMOTE_RUNNING
++ *
++ *
++ * Other transitions get WARN_ON_ONCE(), except that sched_tick_remote()
++ * and sched_tick_start() are happy to leave the state in RUNNING.
++ */
++
++static struct tick_work __percpu *tick_work_cpu;
++
++static void sched_tick_remote(struct work_struct *work)
++{
++	struct delayed_work *dwork = to_delayed_work(work);
++	struct tick_work *twork = container_of(dwork, struct tick_work, work);
++	int cpu = twork->cpu;
++	struct rq *rq = cpu_rq(cpu);
++	struct task_struct *curr;
++	unsigned long flags;
++	u64 delta;
++	int os;
++
++	/*
++	 * Handle the tick only if it appears the remote CPU is running in full
++	 * dynticks mode. The check is racy by nature, but missing a tick or
++	 * having one too much is no big deal because the scheduler tick updates
++	 * statistics and checks timeslices in a time-independent way, regardless
++	 * of when exactly it is running.
++	 */
++	if (!tick_nohz_tick_stopped_cpu(cpu))
++		goto out_requeue;
++
++	raw_spin_lock_irqsave(&rq->lock, flags);
++	curr = rq->curr;
++	if (cpu_is_offline(cpu))
++		goto out_unlock;
++
++	update_rq_clock(rq);
++	if (!is_idle_task(curr)) {
++		/*
++		 * Make sure the next tick runs within a reasonable
++		 * amount of time.
++		 */
++		delta = rq_clock_task(rq) - curr->last_ran;
++		WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
++	}
++	scheduler_task_tick(rq);
++
++	calc_load_nohz_remote(rq);
++out_unlock:
++	raw_spin_unlock_irqrestore(&rq->lock, flags);
++
++out_requeue:
++	/*
++	 * Run the remote tick once per second (1Hz). This arbitrary
++	 * frequency is large enough to avoid overload but short enough
++	 * to keep scheduler internal stats reasonably up to date.  But
++	 * first update state to reflect hotplug activity if required.
++	 */
++	os = atomic_fetch_add_unless(&twork->state, -1, TICK_SCHED_REMOTE_RUNNING);
++	WARN_ON_ONCE(os == TICK_SCHED_REMOTE_OFFLINE);
++	if (os == TICK_SCHED_REMOTE_RUNNING)
++		queue_delayed_work(system_unbound_wq, dwork, HZ);
++}
++
++static void sched_tick_start(int cpu)
++{
++	int os;
++	struct tick_work *twork;
++
++	if (housekeeping_cpu(cpu, HK_FLAG_TICK))
++		return;
++
++	WARN_ON_ONCE(!tick_work_cpu);
++
++	twork = per_cpu_ptr(tick_work_cpu, cpu);
++	os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_RUNNING);
++	WARN_ON_ONCE(os == TICK_SCHED_REMOTE_RUNNING);
++	if (os == TICK_SCHED_REMOTE_OFFLINE) {
++		twork->cpu = cpu;
++		INIT_DELAYED_WORK(&twork->work, sched_tick_remote);
++		queue_delayed_work(system_unbound_wq, &twork->work, HZ);
++	}
++}
++
++#ifdef CONFIG_HOTPLUG_CPU
++static void sched_tick_stop(int cpu)
++{
++	struct tick_work *twork;
++
++	if (housekeeping_cpu(cpu, HK_FLAG_TICK))
++		return;
++
++	WARN_ON_ONCE(!tick_work_cpu);
++
++	twork = per_cpu_ptr(tick_work_cpu, cpu);
++	cancel_delayed_work_sync(&twork->work);
++}
++#endif /* CONFIG_HOTPLUG_CPU */
++
++int __init sched_tick_offload_init(void)
++{
++	tick_work_cpu = alloc_percpu(struct tick_work);
++	BUG_ON(!tick_work_cpu);
++	return 0;
++}
++
++#else /* !CONFIG_NO_HZ_FULL */
++static inline void sched_tick_start(int cpu) { }
++static inline void sched_tick_stop(int cpu) { }
++#endif
++
++#if defined(CONFIG_PREEMPTION) && (defined(CONFIG_DEBUG_PREEMPT) || \
++				defined(CONFIG_PREEMPT_TRACER))
++/*
++ * If the value passed in is equal to the current preempt count
++ * then we just disabled preemption. Start timing the latency.
++ */
++static inline void preempt_latency_start(int val)
++{
++	if (preempt_count() == val) {
++		unsigned long ip = get_lock_parent_ip();
++#ifdef CONFIG_DEBUG_PREEMPT
++		current->preempt_disable_ip = ip;
++#endif
++		trace_preempt_off(CALLER_ADDR0, ip);
++	}
++}
++
++void preempt_count_add(int val)
++{
++#ifdef CONFIG_DEBUG_PREEMPT
++	/*
++	 * Underflow?
++	 */
++	if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
++		return;
++#endif
++	__preempt_count_add(val);
++#ifdef CONFIG_DEBUG_PREEMPT
++	/*
++	 * Spinlock count overflowing soon?
++	 */
++	DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
++				PREEMPT_MASK - 10);
++#endif
++	preempt_latency_start(val);
++}
++EXPORT_SYMBOL(preempt_count_add);
++NOKPROBE_SYMBOL(preempt_count_add);
++
++/*
++ * If the value passed in equals to the current preempt count
++ * then we just enabled preemption. Stop timing the latency.
++ */
++static inline void preempt_latency_stop(int val)
++{
++	if (preempt_count() == val)
++		trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
++}
++
++void preempt_count_sub(int val)
++{
++#ifdef CONFIG_DEBUG_PREEMPT
++	/*
++	 * Underflow?
++	 */
++	if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
++		return;
++	/*
++	 * Is the spinlock portion underflowing?
++	 */
++	if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
++			!(preempt_count() & PREEMPT_MASK)))
++		return;
++#endif
++
++	preempt_latency_stop(val);
++	__preempt_count_sub(val);
++}
++EXPORT_SYMBOL(preempt_count_sub);
++NOKPROBE_SYMBOL(preempt_count_sub);
++
++#else
++static inline void preempt_latency_start(int val) { }
++static inline void preempt_latency_stop(int val) { }
++#endif
++
++static inline unsigned long get_preempt_disable_ip(struct task_struct *p)
++{
++#ifdef CONFIG_DEBUG_PREEMPT
++	return p->preempt_disable_ip;
++#else
++	return 0;
++#endif
++}
++
++/*
++ * Print scheduling while atomic bug:
++ */
++static noinline void __schedule_bug(struct task_struct *prev)
++{
++	/* Save this before calling printk(), since that will clobber it */
++	unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
++
++	if (oops_in_progress)
++		return;
++
++	printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
++		prev->comm, prev->pid, preempt_count());
++
++	debug_show_held_locks(prev);
++	print_modules();
++	if (irqs_disabled())
++		print_irqtrace_events(prev);
++	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
++	    && in_atomic_preempt_off()) {
++		pr_err("Preemption disabled at:");
++		print_ip_sym(KERN_ERR, preempt_disable_ip);
++	}
++	if (panic_on_warn)
++		panic("scheduling while atomic\n");
++
++	dump_stack();
++	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++}
++
++/*
++ * Various schedule()-time debugging checks and statistics:
++ */
++static inline void schedule_debug(struct task_struct *prev, bool preempt)
++{
++#ifdef CONFIG_SCHED_STACK_END_CHECK
++	if (task_stack_end_corrupted(prev))
++		panic("corrupted stack end detected inside scheduler\n");
++
++	if (task_scs_end_corrupted(prev))
++		panic("corrupted shadow stack detected inside scheduler\n");
++#endif
++
++#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
++	if (!preempt && READ_ONCE(prev->__state) && prev->non_block_count) {
++		printk(KERN_ERR "BUG: scheduling in a non-blocking section: %s/%d/%i\n",
++			prev->comm, prev->pid, prev->non_block_count);
++		dump_stack();
++		add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++	}
++#endif
++
++	if (unlikely(in_atomic_preempt_off())) {
++		__schedule_bug(prev);
++		preempt_count_set(PREEMPT_DISABLED);
++	}
++	rcu_sleep_check();
++	SCHED_WARN_ON(ct_state() == CONTEXT_USER);
++
++	profile_hit(SCHED_PROFILING, __builtin_return_address(0));
++
++	schedstat_inc(this_rq()->sched_count);
++}
++
++/*
++ * Compile time debug macro
++ * #define ALT_SCHED_DEBUG
++ */
++
++#ifdef ALT_SCHED_DEBUG
++void alt_sched_debug(void)
++{
++	printk(KERN_INFO "sched: pending: 0x%04lx, idle: 0x%04lx, sg_idle: 0x%04lx\n",
++	       sched_rq_pending_mask.bits[0],
++	       sched_rq_watermark[0].bits[0],
++	       sched_sg_idle_mask.bits[0]);
++}
++#else
++inline void alt_sched_debug(void) {}
++#endif
++
++#ifdef	CONFIG_SMP
++
++#define SCHED_RQ_NR_MIGRATION (32U)
++/*
++ * Migrate pending tasks in @rq to @dest_cpu
++ * Will try to migrate mininal of half of @rq nr_running tasks and
++ * SCHED_RQ_NR_MIGRATION to @dest_cpu
++ */
++static inline int
++migrate_pending_tasks(struct rq *rq, struct rq *dest_rq, const int dest_cpu)
++{
++	struct task_struct *p, *skip = rq->curr;
++	int nr_migrated = 0;
++	int nr_tries = min(rq->nr_running / 2, SCHED_RQ_NR_MIGRATION);
++
++	while (skip != rq->idle && nr_tries &&
++	       (p = sched_rq_next_task(skip, rq)) != rq->idle) {
++		skip = sched_rq_next_task(p, rq);
++		if (cpumask_test_cpu(dest_cpu, p->cpus_ptr)) {
++			__SCHED_DEQUEUE_TASK(p, rq, 0, );
++			set_task_cpu(p, dest_cpu);
++			sched_task_sanity_check(p, dest_rq);
++			__SCHED_ENQUEUE_TASK(p, dest_rq, 0);
++			nr_migrated++;
++		}
++		nr_tries--;
++	}
++
++	return nr_migrated;
++}
++
++static inline int take_other_rq_tasks(struct rq *rq, int cpu)
++{
++	struct cpumask *topo_mask, *end_mask;
++
++	if (unlikely(!rq->online))
++		return 0;
++
++	if (cpumask_empty(&sched_rq_pending_mask))
++		return 0;
++
++	topo_mask = per_cpu(sched_cpu_topo_masks, cpu) + 1;
++	end_mask = per_cpu(sched_cpu_topo_end_mask, cpu);
++	do {
++		int i;
++		for_each_cpu_and(i, &sched_rq_pending_mask, topo_mask) {
++			int nr_migrated;
++			struct rq *src_rq;
++
++			src_rq = cpu_rq(i);
++			if (!do_raw_spin_trylock(&src_rq->lock))
++				continue;
++			spin_acquire(&src_rq->lock.dep_map,
++				     SINGLE_DEPTH_NESTING, 1, _RET_IP_);
++
++			if ((nr_migrated = migrate_pending_tasks(src_rq, rq, cpu))) {
++				src_rq->nr_running -= nr_migrated;
++				if (src_rq->nr_running < 2)
++					cpumask_clear_cpu(i, &sched_rq_pending_mask);
++
++				rq->nr_running += nr_migrated;
++				if (rq->nr_running > 1)
++					cpumask_set_cpu(cpu, &sched_rq_pending_mask);
++
++				update_sched_rq_watermark(rq);
++				cpufreq_update_util(rq, 0);
++
++				spin_release(&src_rq->lock.dep_map, _RET_IP_);
++				do_raw_spin_unlock(&src_rq->lock);
++
++				return 1;
++			}
++
++			spin_release(&src_rq->lock.dep_map, _RET_IP_);
++			do_raw_spin_unlock(&src_rq->lock);
++		}
++	} while (++topo_mask < end_mask);
++
++	return 0;
++}
++#endif
++
++/*
++ * Timeslices below RESCHED_NS are considered as good as expired as there's no
++ * point rescheduling when there's so little time left.
++ */
++static inline void check_curr(struct task_struct *p, struct rq *rq)
++{
++	if (unlikely(rq->idle == p))
++		return;
++
++	update_curr(rq, p);
++
++	if (p->time_slice < RESCHED_NS)
++		time_slice_expired(p, rq);
++}
++
++static inline struct task_struct *
++choose_next_task(struct rq *rq, int cpu, struct task_struct *prev)
++{
++	struct task_struct *next;
++
++	if (unlikely(rq->skip)) {
++		next = rq_runnable_task(rq);
++		if (next == rq->idle) {
++#ifdef	CONFIG_SMP
++			if (!take_other_rq_tasks(rq, cpu)) {
++#endif
++				rq->skip = NULL;
++				schedstat_inc(rq->sched_goidle);
++				return next;
++#ifdef	CONFIG_SMP
++			}
++			next = rq_runnable_task(rq);
++#endif
++		}
++		rq->skip = NULL;
++#ifdef CONFIG_HIGH_RES_TIMERS
++		hrtick_start(rq, next->time_slice);
++#endif
++		return next;
++	}
++
++	next = sched_rq_first_task(rq);
++	if (next == rq->idle) {
++#ifdef	CONFIG_SMP
++		if (!take_other_rq_tasks(rq, cpu)) {
++#endif
++			schedstat_inc(rq->sched_goidle);
++			/*printk(KERN_INFO "sched: choose_next_task(%d) idle %px\n", cpu, next);*/
++			return next;
++#ifdef	CONFIG_SMP
++		}
++		next = sched_rq_first_task(rq);
++#endif
++	}
++#ifdef CONFIG_HIGH_RES_TIMERS
++	hrtick_start(rq, next->time_slice);
++#endif
++	/*printk(KERN_INFO "sched: choose_next_task(%d) next %px\n", cpu,
++	 * next);*/
++	return next;
++}
++
++/*
++ * Constants for the sched_mode argument of __schedule().
++ *
++ * The mode argument allows RT enabled kernels to differentiate a
++ * preemption from blocking on an 'sleeping' spin/rwlock. Note that
++ * SM_MASK_PREEMPT for !RT has all bits set, which allows the compiler to
++ * optimize the AND operation out and just check for zero.
++ */
++#define SM_NONE			0x0
++#define SM_PREEMPT		0x1
++#define SM_RTLOCK_WAIT		0x2
++
++#ifndef CONFIG_PREEMPT_RT
++# define SM_MASK_PREEMPT	(~0U)
++#else
++# define SM_MASK_PREEMPT	SM_PREEMPT
++#endif
++
++/*
++ * schedule() is the main scheduler function.
++ *
++ * The main means of driving the scheduler and thus entering this function are:
++ *
++ *   1. Explicit blocking: mutex, semaphore, waitqueue, etc.
++ *
++ *   2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
++ *      paths. For example, see arch/x86/entry_64.S.
++ *
++ *      To drive preemption between tasks, the scheduler sets the flag in timer
++ *      interrupt handler scheduler_tick().
++ *
++ *   3. Wakeups don't really cause entry into schedule(). They add a
++ *      task to the run-queue and that's it.
++ *
++ *      Now, if the new task added to the run-queue preempts the current
++ *      task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
++ *      called on the nearest possible occasion:
++ *
++ *       - If the kernel is preemptible (CONFIG_PREEMPTION=y):
++ *
++ *         - in syscall or exception context, at the next outmost
++ *           preempt_enable(). (this might be as soon as the wake_up()'s
++ *           spin_unlock()!)
++ *
++ *         - in IRQ context, return from interrupt-handler to
++ *           preemptible context
++ *
++ *       - If the kernel is not preemptible (CONFIG_PREEMPTION is not set)
++ *         then at the next:
++ *
++ *          - cond_resched() call
++ *          - explicit schedule() call
++ *          - return from syscall or exception to user-space
++ *          - return from interrupt-handler to user-space
++ *
++ * WARNING: must be called with preemption disabled!
++ */
++static void __sched notrace __schedule(unsigned int sched_mode)
++{
++	struct task_struct *prev, *next;
++	unsigned long *switch_count;
++	unsigned long prev_state;
++	struct rq *rq;
++	int cpu;
++
++	cpu = smp_processor_id();
++	rq = cpu_rq(cpu);
++	prev = rq->curr;
++
++	schedule_debug(prev, !!sched_mode);
++
++	/* by passing sched_feat(HRTICK) checking which Alt schedule FW doesn't support */
++	hrtick_clear(rq);
++
++	local_irq_disable();
++	rcu_note_context_switch(!!sched_mode);
++
++	/*
++	 * Make sure that signal_pending_state()->signal_pending() below
++	 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
++	 * done by the caller to avoid the race with signal_wake_up():
++	 *
++	 * __set_current_state(@state)		signal_wake_up()
++	 * schedule()				  set_tsk_thread_flag(p, TIF_SIGPENDING)
++	 *					  wake_up_state(p, state)
++	 *   LOCK rq->lock			    LOCK p->pi_state
++	 *   smp_mb__after_spinlock()		    smp_mb__after_spinlock()
++	 *     if (signal_pending_state())	    if (p->state & @state)
++	 *
++	 * Also, the membarrier system call requires a full memory barrier
++	 * after coming from user-space, before storing to rq->curr.
++	 */
++	raw_spin_lock(&rq->lock);
++	smp_mb__after_spinlock();
++
++	update_rq_clock(rq);
++
++	switch_count = &prev->nivcsw;
++	/*
++	 * We must load prev->state once (task_struct::state is volatile), such
++	 * that:
++	 *
++	 *  - we form a control dependency vs deactivate_task() below.
++	 *  - ptrace_{,un}freeze_traced() can change ->state underneath us.
++	 */
++	prev_state = READ_ONCE(prev->__state);
++	if (!(sched_mode & SM_MASK_PREEMPT) && prev_state) {
++		if (signal_pending_state(prev_state, prev)) {
++			WRITE_ONCE(prev->__state, TASK_RUNNING);
++		} else {
++			prev->sched_contributes_to_load =
++				(prev_state & TASK_UNINTERRUPTIBLE) &&
++				!(prev_state & TASK_NOLOAD) &&
++				!(prev->flags & PF_FROZEN);
++
++			if (prev->sched_contributes_to_load)
++				rq->nr_uninterruptible++;
++
++			/*
++			 * __schedule()			ttwu()
++			 *   prev_state = prev->state;    if (p->on_rq && ...)
++			 *   if (prev_state)		    goto out;
++			 *     p->on_rq = 0;		  smp_acquire__after_ctrl_dep();
++			 *				  p->state = TASK_WAKING
++			 *
++			 * Where __schedule() and ttwu() have matching control dependencies.
++			 *
++			 * After this, schedule() must not care about p->state any more.
++			 */
++			sched_task_deactivate(prev, rq);
++			deactivate_task(prev, rq);
++
++			if (prev->in_iowait) {
++				atomic_inc(&rq->nr_iowait);
++				delayacct_blkio_start();
++			}
++		}
++		switch_count = &prev->nvcsw;
++	}
++
++	check_curr(prev, rq);
++
++	next = choose_next_task(rq, cpu, prev);
++	clear_tsk_need_resched(prev);
++	clear_preempt_need_resched();
++#ifdef CONFIG_SCHED_DEBUG
++	rq->last_seen_need_resched_ns = 0;
++#endif
++
++	if (likely(prev != next)) {
++		next->last_ran = rq->clock_task;
++		rq->last_ts_switch = rq->clock;
++
++		rq->nr_switches++;
++		/*
++		 * RCU users of rcu_dereference(rq->curr) may not see
++		 * changes to task_struct made by pick_next_task().
++		 */
++		RCU_INIT_POINTER(rq->curr, next);
++		/*
++		 * The membarrier system call requires each architecture
++		 * to have a full memory barrier after updating
++		 * rq->curr, before returning to user-space.
++		 *
++		 * Here are the schemes providing that barrier on the
++		 * various architectures:
++		 * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC.
++		 *   switch_mm() rely on membarrier_arch_switch_mm() on PowerPC.
++		 * - finish_lock_switch() for weakly-ordered
++		 *   architectures where spin_unlock is a full barrier,
++		 * - switch_to() for arm64 (weakly-ordered, spin_unlock
++		 *   is a RELEASE barrier),
++		 */
++		++*switch_count;
++
++		psi_sched_switch(prev, next, !task_on_rq_queued(prev));
++
++		trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev, next);
++
++		/* Also unlocks the rq: */
++		rq = context_switch(rq, prev, next);
++	} else {
++		__balance_callbacks(rq);
++		raw_spin_unlock_irq(&rq->lock);
++	}
++
++#ifdef CONFIG_SCHED_SMT
++	sg_balance_check(rq);
++#endif
++}
++
++void __noreturn do_task_dead(void)
++{
++	/* Causes final put_task_struct in finish_task_switch(): */
++	set_special_state(TASK_DEAD);
++
++	/* Tell freezer to ignore us: */
++	current->flags |= PF_NOFREEZE;
++
++	__schedule(SM_NONE);
++	BUG();
++
++	/* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */
++	for (;;)
++		cpu_relax();
++}
++
++static inline void sched_submit_work(struct task_struct *tsk)
++{
++	unsigned int task_flags;
++
++	if (task_is_running(tsk))
++		return;
++
++	task_flags = tsk->flags;
++	/*
++	 * If a worker went to sleep, notify and ask workqueue whether
++	 * it wants to wake up a task to maintain concurrency.
++	 * As this function is called inside the schedule() context,
++	 * we disable preemption to avoid it calling schedule() again
++	 * in the possible wakeup of a kworker and because wq_worker_sleeping()
++	 * requires it.
++	 */
++	if (task_flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
++		preempt_disable();
++		if (task_flags & PF_WQ_WORKER)
++			wq_worker_sleeping(tsk);
++		else
++			io_wq_worker_sleeping(tsk);
++		preempt_enable_no_resched();
++	}
++
++	if (tsk_is_pi_blocked(tsk))
++		return;
++
++	/*
++	 * If we are going to sleep and we have plugged IO queued,
++	 * make sure to submit it to avoid deadlocks.
++	 */
++	if (blk_needs_flush_plug(tsk))
++		blk_schedule_flush_plug(tsk);
++}
++
++static void sched_update_worker(struct task_struct *tsk)
++{
++	if (tsk->flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
++		if (tsk->flags & PF_WQ_WORKER)
++			wq_worker_running(tsk);
++		else
++			io_wq_worker_running(tsk);
++	}
++}
++
++asmlinkage __visible void __sched schedule(void)
++{
++	struct task_struct *tsk = current;
++
++	sched_submit_work(tsk);
++	do {
++		preempt_disable();
++		__schedule(SM_NONE);
++		sched_preempt_enable_no_resched();
++	} while (need_resched());
++	sched_update_worker(tsk);
++}
++EXPORT_SYMBOL(schedule);
++
++/*
++ * synchronize_rcu_tasks() makes sure that no task is stuck in preempted
++ * state (have scheduled out non-voluntarily) by making sure that all
++ * tasks have either left the run queue or have gone into user space.
++ * As idle tasks do not do either, they must not ever be preempted
++ * (schedule out non-voluntarily).
++ *
++ * schedule_idle() is similar to schedule_preempt_disable() except that it
++ * never enables preemption because it does not call sched_submit_work().
++ */
++void __sched schedule_idle(void)
++{
++	/*
++	 * As this skips calling sched_submit_work(), which the idle task does
++	 * regardless because that function is a nop when the task is in a
++	 * TASK_RUNNING state, make sure this isn't used someplace that the
++	 * current task can be in any other state. Note, idle is always in the
++	 * TASK_RUNNING state.
++	 */
++	WARN_ON_ONCE(current->__state);
++	do {
++		__schedule(SM_NONE);
++	} while (need_resched());
++}
++
++#if defined(CONFIG_CONTEXT_TRACKING) && !defined(CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK)
++asmlinkage __visible void __sched schedule_user(void)
++{
++	/*
++	 * If we come here after a random call to set_need_resched(),
++	 * or we have been woken up remotely but the IPI has not yet arrived,
++	 * we haven't yet exited the RCU idle mode. Do it here manually until
++	 * we find a better solution.
++	 *
++	 * NB: There are buggy callers of this function.  Ideally we
++	 * should warn if prev_state != CONTEXT_USER, but that will trigger
++	 * too frequently to make sense yet.
++	 */
++	enum ctx_state prev_state = exception_enter();
++	schedule();
++	exception_exit(prev_state);
++}
++#endif
++
++/**
++ * schedule_preempt_disabled - called with preemption disabled
++ *
++ * Returns with preemption disabled. Note: preempt_count must be 1
++ */
++void __sched schedule_preempt_disabled(void)
++{
++	sched_preempt_enable_no_resched();
++	schedule();
++	preempt_disable();
++}
++
++#ifdef CONFIG_PREEMPT_RT
++void __sched notrace schedule_rtlock(void)
++{
++	do {
++		preempt_disable();
++		__schedule(SM_RTLOCK_WAIT);
++		sched_preempt_enable_no_resched();
++	} while (need_resched());
++}
++NOKPROBE_SYMBOL(schedule_rtlock);
++#endif
++
++static void __sched notrace preempt_schedule_common(void)
++{
++	do {
++		/*
++		 * Because the function tracer can trace preempt_count_sub()
++		 * and it also uses preempt_enable/disable_notrace(), if
++		 * NEED_RESCHED is set, the preempt_enable_notrace() called
++		 * by the function tracer will call this function again and
++		 * cause infinite recursion.
++		 *
++		 * Preemption must be disabled here before the function
++		 * tracer can trace. Break up preempt_disable() into two
++		 * calls. One to disable preemption without fear of being
++		 * traced. The other to still record the preemption latency,
++		 * which can also be traced by the function tracer.
++		 */
++		preempt_disable_notrace();
++		preempt_latency_start(1);
++		__schedule(SM_PREEMPT);
++		preempt_latency_stop(1);
++		preempt_enable_no_resched_notrace();
++
++		/*
++		 * Check again in case we missed a preemption opportunity
++		 * between schedule and now.
++		 */
++	} while (need_resched());
++}
++
++#ifdef CONFIG_PREEMPTION
++/*
++ * This is the entry point to schedule() from in-kernel preemption
++ * off of preempt_enable.
++ */
++asmlinkage __visible void __sched notrace preempt_schedule(void)
++{
++	/*
++	 * If there is a non-zero preempt_count or interrupts are disabled,
++	 * we do not want to preempt the current task. Just return..
++	 */
++	if (likely(!preemptible()))
++		return;
++
++	preempt_schedule_common();
++}
++NOKPROBE_SYMBOL(preempt_schedule);
++EXPORT_SYMBOL(preempt_schedule);
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++DEFINE_STATIC_CALL(preempt_schedule, __preempt_schedule_func);
++EXPORT_STATIC_CALL_TRAMP(preempt_schedule);
++#endif
++
++
++/**
++ * preempt_schedule_notrace - preempt_schedule called by tracing
++ *
++ * The tracing infrastructure uses preempt_enable_notrace to prevent
++ * recursion and tracing preempt enabling caused by the tracing
++ * infrastructure itself. But as tracing can happen in areas coming
++ * from userspace or just about to enter userspace, a preempt enable
++ * can occur before user_exit() is called. This will cause the scheduler
++ * to be called when the system is still in usermode.
++ *
++ * To prevent this, the preempt_enable_notrace will use this function
++ * instead of preempt_schedule() to exit user context if needed before
++ * calling the scheduler.
++ */
++asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
++{
++	enum ctx_state prev_ctx;
++
++	if (likely(!preemptible()))
++		return;
++
++	do {
++		/*
++		 * Because the function tracer can trace preempt_count_sub()
++		 * and it also uses preempt_enable/disable_notrace(), if
++		 * NEED_RESCHED is set, the preempt_enable_notrace() called
++		 * by the function tracer will call this function again and
++		 * cause infinite recursion.
++		 *
++		 * Preemption must be disabled here before the function
++		 * tracer can trace. Break up preempt_disable() into two
++		 * calls. One to disable preemption without fear of being
++		 * traced. The other to still record the preemption latency,
++		 * which can also be traced by the function tracer.
++		 */
++		preempt_disable_notrace();
++		preempt_latency_start(1);
++		/*
++		 * Needs preempt disabled in case user_exit() is traced
++		 * and the tracer calls preempt_enable_notrace() causing
++		 * an infinite recursion.
++		 */
++		prev_ctx = exception_enter();
++		__schedule(SM_PREEMPT);
++		exception_exit(prev_ctx);
++
++		preempt_latency_stop(1);
++		preempt_enable_no_resched_notrace();
++	} while (need_resched());
++}
++EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++DEFINE_STATIC_CALL(preempt_schedule_notrace, __preempt_schedule_notrace_func);
++EXPORT_STATIC_CALL_TRAMP(preempt_schedule_notrace);
++#endif
++
++#endif /* CONFIG_PREEMPTION */
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++
++#include <linux/entry-common.h>
++
++/*
++ * SC:cond_resched
++ * SC:might_resched
++ * SC:preempt_schedule
++ * SC:preempt_schedule_notrace
++ * SC:irqentry_exit_cond_resched
++ *
++ *
++ * NONE:
++ *   cond_resched               <- __cond_resched
++ *   might_resched              <- RET0
++ *   preempt_schedule           <- NOP
++ *   preempt_schedule_notrace   <- NOP
++ *   irqentry_exit_cond_resched <- NOP
++ *
++ * VOLUNTARY:
++ *   cond_resched               <- __cond_resched
++ *   might_resched              <- __cond_resched
++ *   preempt_schedule           <- NOP
++ *   preempt_schedule_notrace   <- NOP
++ *   irqentry_exit_cond_resched <- NOP
++ *
++ * FULL:
++ *   cond_resched               <- RET0
++ *   might_resched              <- RET0
++ *   preempt_schedule           <- preempt_schedule
++ *   preempt_schedule_notrace   <- preempt_schedule_notrace
++ *   irqentry_exit_cond_resched <- irqentry_exit_cond_resched
++ */
++
++enum {
++	preempt_dynamic_none = 0,
++	preempt_dynamic_voluntary,
++	preempt_dynamic_full,
++};
++
++int preempt_dynamic_mode = preempt_dynamic_full;
++
++int sched_dynamic_mode(const char *str)
++{
++	if (!strcmp(str, "none"))
++		return preempt_dynamic_none;
++
++	if (!strcmp(str, "voluntary"))
++		return preempt_dynamic_voluntary;
++
++	if (!strcmp(str, "full"))
++		return preempt_dynamic_full;
++
++	return -EINVAL;
++}
++
++void sched_dynamic_update(int mode)
++{
++	/*
++	 * Avoid {NONE,VOLUNTARY} -> FULL transitions from ever ending up in
++	 * the ZERO state, which is invalid.
++	 */
++	static_call_update(cond_resched, __cond_resched);
++	static_call_update(might_resched, __cond_resched);
++	static_call_update(preempt_schedule, __preempt_schedule_func);
++	static_call_update(preempt_schedule_notrace, __preempt_schedule_notrace_func);
++	static_call_update(irqentry_exit_cond_resched, irqentry_exit_cond_resched);
++
++	switch (mode) {
++	case preempt_dynamic_none:
++		static_call_update(cond_resched, __cond_resched);
++		static_call_update(might_resched, (void *)&__static_call_return0);
++		static_call_update(preempt_schedule, NULL);
++		static_call_update(preempt_schedule_notrace, NULL);
++		static_call_update(irqentry_exit_cond_resched, NULL);
++		pr_info("Dynamic Preempt: none\n");
++		break;
++
++	case preempt_dynamic_voluntary:
++		static_call_update(cond_resched, __cond_resched);
++		static_call_update(might_resched, __cond_resched);
++		static_call_update(preempt_schedule, NULL);
++		static_call_update(preempt_schedule_notrace, NULL);
++		static_call_update(irqentry_exit_cond_resched, NULL);
++		pr_info("Dynamic Preempt: voluntary\n");
++		break;
++
++	case preempt_dynamic_full:
++		static_call_update(cond_resched, (void *)&__static_call_return0);
++		static_call_update(might_resched, (void *)&__static_call_return0);
++		static_call_update(preempt_schedule, __preempt_schedule_func);
++		static_call_update(preempt_schedule_notrace, __preempt_schedule_notrace_func);
++		static_call_update(irqentry_exit_cond_resched, irqentry_exit_cond_resched);
++		pr_info("Dynamic Preempt: full\n");
++		break;
++	}
++
++	preempt_dynamic_mode = mode;
++}
++
++static int __init setup_preempt_mode(char *str)
++{
++	int mode = sched_dynamic_mode(str);
++	if (mode < 0) {
++		pr_warn("Dynamic Preempt: unsupported mode: %s\n", str);
++		return 1;
++	}
++
++	sched_dynamic_update(mode);
++	return 0;
++}
++__setup("preempt=", setup_preempt_mode);
++
++#endif /* CONFIG_PREEMPT_DYNAMIC */
++
++/*
++ * This is the entry point to schedule() from kernel preemption
++ * off of irq context.
++ * Note, that this is called and return with irqs disabled. This will
++ * protect us against recursive calling from irq.
++ */
++asmlinkage __visible void __sched preempt_schedule_irq(void)
++{
++	enum ctx_state prev_state;
++
++	/* Catch callers which need to be fixed */
++	BUG_ON(preempt_count() || !irqs_disabled());
++
++	prev_state = exception_enter();
++
++	do {
++		preempt_disable();
++		local_irq_enable();
++		__schedule(SM_PREEMPT);
++		local_irq_disable();
++		sched_preempt_enable_no_resched();
++	} while (need_resched());
++
++	exception_exit(prev_state);
++}
++
++int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags,
++			  void *key)
++{
++	WARN_ON_ONCE(IS_ENABLED(CONFIG_SCHED_DEBUG) && wake_flags & ~WF_SYNC);
++	return try_to_wake_up(curr->private, mode, wake_flags);
++}
++EXPORT_SYMBOL(default_wake_function);
++
++static inline void check_task_changed(struct task_struct *p, struct rq *rq)
++{
++	/* Trigger resched if task sched_prio has been modified. */
++	if (task_on_rq_queued(p) && task_sched_prio_idx(p, rq) != p->sq_idx) {
++		requeue_task(p, rq);
++		check_preempt_curr(rq);
++	}
++}
++
++static void __setscheduler_prio(struct task_struct *p, int prio)
++{
++	p->prio = prio;
++}
++
++#ifdef CONFIG_RT_MUTEXES
++
++static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
++{
++	if (pi_task)
++		prio = min(prio, pi_task->prio);
++
++	return prio;
++}
++
++static inline int rt_effective_prio(struct task_struct *p, int prio)
++{
++	struct task_struct *pi_task = rt_mutex_get_top_task(p);
++
++	return __rt_effective_prio(pi_task, prio);
++}
++
++/*
++ * rt_mutex_setprio - set the current priority of a task
++ * @p: task to boost
++ * @pi_task: donor task
++ *
++ * This function changes the 'effective' priority of a task. It does
++ * not touch ->normal_prio like __setscheduler().
++ *
++ * Used by the rt_mutex code to implement priority inheritance
++ * logic. Call site only calls if the priority of the task changed.
++ */
++void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
++{
++	int prio;
++	struct rq *rq;
++	raw_spinlock_t *lock;
++
++	/* XXX used to be waiter->prio, not waiter->task->prio */
++	prio = __rt_effective_prio(pi_task, p->normal_prio);
++
++	/*
++	 * If nothing changed; bail early.
++	 */
++	if (p->pi_top_task == pi_task && prio == p->prio)
++		return;
++
++	rq = __task_access_lock(p, &lock);
++	/*
++	 * Set under pi_lock && rq->lock, such that the value can be used under
++	 * either lock.
++	 *
++	 * Note that there is loads of tricky to make this pointer cache work
++	 * right. rt_mutex_slowunlock()+rt_mutex_postunlock() work together to
++	 * ensure a task is de-boosted (pi_task is set to NULL) before the
++	 * task is allowed to run again (and can exit). This ensures the pointer
++	 * points to a blocked task -- which guarantees the task is present.
++	 */
++	p->pi_top_task = pi_task;
++
++	/*
++	 * For FIFO/RR we only need to set prio, if that matches we're done.
++	 */
++	if (prio == p->prio)
++		goto out_unlock;
++
++	/*
++	 * Idle task boosting is a nono in general. There is one
++	 * exception, when PREEMPT_RT and NOHZ is active:
++	 *
++	 * The idle task calls get_next_timer_interrupt() and holds
++	 * the timer wheel base->lock on the CPU and another CPU wants
++	 * to access the timer (probably to cancel it). We can safely
++	 * ignore the boosting request, as the idle CPU runs this code
++	 * with interrupts disabled and will complete the lock
++	 * protected section without being interrupted. So there is no
++	 * real need to boost.
++	 */
++	if (unlikely(p == rq->idle)) {
++		WARN_ON(p != rq->curr);
++		WARN_ON(p->pi_blocked_on);
++		goto out_unlock;
++	}
++
++	trace_sched_pi_setprio(p, pi_task);
++
++	__setscheduler_prio(p, prio);
++
++	check_task_changed(p, rq);
++out_unlock:
++	/* Avoid rq from going away on us: */
++	preempt_disable();
++
++	__balance_callbacks(rq);
++	__task_access_unlock(p, lock);
++
++	preempt_enable();
++}
++#else
++static inline int rt_effective_prio(struct task_struct *p, int prio)
++{
++	return prio;
++}
++#endif
++
++void set_user_nice(struct task_struct *p, long nice)
++{
++	unsigned long flags;
++	struct rq *rq;
++	raw_spinlock_t *lock;
++
++	if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
++		return;
++	/*
++	 * We have to be careful, if called from sys_setpriority(),
++	 * the task might be in the middle of scheduling on another CPU.
++	 */
++	raw_spin_lock_irqsave(&p->pi_lock, flags);
++	rq = __task_access_lock(p, &lock);
++
++	p->static_prio = NICE_TO_PRIO(nice);
++	/*
++	 * The RT priorities are set via sched_setscheduler(), but we still
++	 * allow the 'normal' nice value to be set - but as expected
++	 * it won't have any effect on scheduling until the task is
++	 * not SCHED_NORMAL/SCHED_BATCH:
++	 */
++	if (task_has_rt_policy(p))
++		goto out_unlock;
++
++	p->prio = effective_prio(p);
++
++	check_task_changed(p, rq);
++out_unlock:
++	__task_access_unlock(p, lock);
++	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++}
++EXPORT_SYMBOL(set_user_nice);
++
++/*
++ * can_nice - check if a task can reduce its nice value
++ * @p: task
++ * @nice: nice value
++ */
++int can_nice(const struct task_struct *p, const int nice)
++{
++	/* Convert nice value [19,-20] to rlimit style value [1,40] */
++	int nice_rlim = nice_to_rlimit(nice);
++
++	return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
++		capable(CAP_SYS_NICE));
++}
++
++#ifdef __ARCH_WANT_SYS_NICE
++
++/*
++ * sys_nice - change the priority of the current process.
++ * @increment: priority increment
++ *
++ * sys_setpriority is a more generic, but much slower function that
++ * does similar things.
++ */
++SYSCALL_DEFINE1(nice, int, increment)
++{
++	long nice, retval;
++
++	/*
++	 * Setpriority might change our priority at the same moment.
++	 * We don't have to worry. Conceptually one call occurs first
++	 * and we have a single winner.
++	 */
++
++	increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
++	nice = task_nice(current) + increment;
++
++	nice = clamp_val(nice, MIN_NICE, MAX_NICE);
++	if (increment < 0 && !can_nice(current, nice))
++		return -EPERM;
++
++	retval = security_task_setnice(current, nice);
++	if (retval)
++		return retval;
++
++	set_user_nice(current, nice);
++	return 0;
++}
++
++#endif
++
++/**
++ * task_prio - return the priority value of a given task.
++ * @p: the task in question.
++ *
++ * Return: The priority value as seen by users in /proc.
++ *
++ * sched policy         return value   kernel prio    user prio/nice
++ *
++ * (BMQ)normal, batch, idle[0 ... 53]  [100 ... 139]          0/[-20 ... 19]/[-7 ... 7]
++ * (PDS)normal, batch, idle[0 ... 39]            100          0/[-20 ... 19]
++ * fifo, rr             [-1 ... -100]     [99 ... 0]  [0 ... 99]
++ */
++int task_prio(const struct task_struct *p)
++{
++	return (p->prio < MAX_RT_PRIO) ? p->prio - MAX_RT_PRIO :
++		task_sched_prio_normal(p, task_rq(p));
++}
++
++/**
++ * idle_cpu - is a given CPU idle currently?
++ * @cpu: the processor in question.
++ *
++ * Return: 1 if the CPU is currently idle. 0 otherwise.
++ */
++int idle_cpu(int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++
++	if (rq->curr != rq->idle)
++		return 0;
++
++	if (rq->nr_running)
++		return 0;
++
++#ifdef CONFIG_SMP
++	if (rq->ttwu_pending)
++		return 0;
++#endif
++
++	return 1;
++}
++
++/**
++ * idle_task - return the idle task for a given CPU.
++ * @cpu: the processor in question.
++ *
++ * Return: The idle task for the cpu @cpu.
++ */
++struct task_struct *idle_task(int cpu)
++{
++	return cpu_rq(cpu)->idle;
++}
++
++/**
++ * find_process_by_pid - find a process with a matching PID value.
++ * @pid: the pid in question.
++ *
++ * The task of @pid, if found. %NULL otherwise.
++ */
++static inline struct task_struct *find_process_by_pid(pid_t pid)
++{
++	return pid ? find_task_by_vpid(pid) : current;
++}
++
++/*
++ * sched_setparam() passes in -1 for its policy, to let the functions
++ * it calls know not to change it.
++ */
++#define SETPARAM_POLICY -1
++
++static void __setscheduler_params(struct task_struct *p,
++		const struct sched_attr *attr)
++{
++	int policy = attr->sched_policy;
++
++	if (policy == SETPARAM_POLICY)
++		policy = p->policy;
++
++	p->policy = policy;
++
++	/*
++	 * allow normal nice value to be set, but will not have any
++	 * effect on scheduling until the task not SCHED_NORMAL/
++	 * SCHED_BATCH
++	 */
++	p->static_prio = NICE_TO_PRIO(attr->sched_nice);
++
++	/*
++	 * __sched_setscheduler() ensures attr->sched_priority == 0 when
++	 * !rt_policy. Always setting this ensures that things like
++	 * getparam()/getattr() don't report silly values for !rt tasks.
++	 */
++	p->rt_priority = attr->sched_priority;
++	p->normal_prio = normal_prio(p);
++}
++
++/*
++ * check the target process has a UID that matches the current process's
++ */
++static bool check_same_owner(struct task_struct *p)
++{
++	const struct cred *cred = current_cred(), *pcred;
++	bool match;
++
++	rcu_read_lock();
++	pcred = __task_cred(p);
++	match = (uid_eq(cred->euid, pcred->euid) ||
++		 uid_eq(cred->euid, pcred->uid));
++	rcu_read_unlock();
++	return match;
++}
++
++static int __sched_setscheduler(struct task_struct *p,
++				const struct sched_attr *attr,
++				bool user, bool pi)
++{
++	const struct sched_attr dl_squash_attr = {
++		.size		= sizeof(struct sched_attr),
++		.sched_policy	= SCHED_FIFO,
++		.sched_nice	= 0,
++		.sched_priority = 99,
++	};
++	int oldpolicy = -1, policy = attr->sched_policy;
++	int retval, newprio;
++	struct callback_head *head;
++	unsigned long flags;
++	struct rq *rq;
++	int reset_on_fork;
++	raw_spinlock_t *lock;
++
++	/* The pi code expects interrupts enabled */
++	BUG_ON(pi && in_interrupt());
++
++	/*
++	 * Alt schedule FW supports SCHED_DEADLINE by squash it as prio 0 SCHED_FIFO
++	 */
++	if (unlikely(SCHED_DEADLINE == policy)) {
++		attr = &dl_squash_attr;
++		policy = attr->sched_policy;
++	}
++recheck:
++	/* Double check policy once rq lock held */
++	if (policy < 0) {
++		reset_on_fork = p->sched_reset_on_fork;
++		policy = oldpolicy = p->policy;
++	} else {
++		reset_on_fork = !!(attr->sched_flags & SCHED_RESET_ON_FORK);
++
++		if (policy > SCHED_IDLE)
++			return -EINVAL;
++	}
++
++	if (attr->sched_flags & ~(SCHED_FLAG_ALL))
++		return -EINVAL;
++
++	/*
++	 * Valid priorities for SCHED_FIFO and SCHED_RR are
++	 * 1..MAX_RT_PRIO-1, valid priority for SCHED_NORMAL and
++	 * SCHED_BATCH and SCHED_IDLE is 0.
++	 */
++	if (attr->sched_priority < 0 ||
++	    (p->mm && attr->sched_priority > MAX_RT_PRIO - 1) ||
++	    (!p->mm && attr->sched_priority > MAX_RT_PRIO - 1))
++		return -EINVAL;
++	if ((SCHED_RR == policy || SCHED_FIFO == policy) !=
++	    (attr->sched_priority != 0))
++		return -EINVAL;
++
++	/*
++	 * Allow unprivileged RT tasks to decrease priority:
++	 */
++	if (user && !capable(CAP_SYS_NICE)) {
++		if (SCHED_FIFO == policy || SCHED_RR == policy) {
++			unsigned long rlim_rtprio =
++					task_rlimit(p, RLIMIT_RTPRIO);
++
++			/* Can't set/change the rt policy */
++			if (policy != p->policy && !rlim_rtprio)
++				return -EPERM;
++
++			/* Can't increase priority */
++			if (attr->sched_priority > p->rt_priority &&
++			    attr->sched_priority > rlim_rtprio)
++				return -EPERM;
++		}
++
++		/* Can't change other user's priorities */
++		if (!check_same_owner(p))
++			return -EPERM;
++
++		/* Normal users shall not reset the sched_reset_on_fork flag */
++		if (p->sched_reset_on_fork && !reset_on_fork)
++			return -EPERM;
++	}
++
++	if (user) {
++		retval = security_task_setscheduler(p);
++		if (retval)
++			return retval;
++	}
++
++	if (pi)
++		cpuset_read_lock();
++
++	/*
++	 * Make sure no PI-waiters arrive (or leave) while we are
++	 * changing the priority of the task:
++	 */
++	raw_spin_lock_irqsave(&p->pi_lock, flags);
++
++	/*
++	 * To be able to change p->policy safely, task_access_lock()
++	 * must be called.
++	 * IF use task_access_lock() here:
++	 * For the task p which is not running, reading rq->stop is
++	 * racy but acceptable as ->stop doesn't change much.
++	 * An enhancemnet can be made to read rq->stop saftly.
++	 */
++	rq = __task_access_lock(p, &lock);
++
++	/*
++	 * Changing the policy of the stop threads its a very bad idea
++	 */
++	if (p == rq->stop) {
++		retval = -EINVAL;
++		goto unlock;
++	}
++
++	/*
++	 * If not changing anything there's no need to proceed further:
++	 */
++	if (unlikely(policy == p->policy)) {
++		if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
++			goto change;
++		if (!rt_policy(policy) &&
++		    NICE_TO_PRIO(attr->sched_nice) != p->static_prio)
++			goto change;
++
++		p->sched_reset_on_fork = reset_on_fork;
++		retval = 0;
++		goto unlock;
++	}
++change:
++
++	/* Re-check policy now with rq lock held */
++	if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
++		policy = oldpolicy = -1;
++		__task_access_unlock(p, lock);
++		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++		if (pi)
++			cpuset_read_unlock();
++		goto recheck;
++	}
++
++	p->sched_reset_on_fork = reset_on_fork;
++
++	newprio = __normal_prio(policy, attr->sched_priority, NICE_TO_PRIO(attr->sched_nice));
++	if (pi) {
++		/*
++		 * Take priority boosted tasks into account. If the new
++		 * effective priority is unchanged, we just store the new
++		 * normal parameters and do not touch the scheduler class and
++		 * the runqueue. This will be done when the task deboost
++		 * itself.
++		 */
++		newprio = rt_effective_prio(p, newprio);
++	}
++
++	if (!(attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)) {
++		__setscheduler_params(p, attr);
++		__setscheduler_prio(p, newprio);
++	}
++
++	check_task_changed(p, rq);
++
++	/* Avoid rq from going away on us: */
++	preempt_disable();
++	head = splice_balance_callbacks(rq);
++	__task_access_unlock(p, lock);
++	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++
++	if (pi) {
++		cpuset_read_unlock();
++		rt_mutex_adjust_pi(p);
++	}
++
++	/* Run balance callbacks after we've adjusted the PI chain: */
++	balance_callbacks(rq, head);
++	preempt_enable();
++
++	return 0;
++
++unlock:
++	__task_access_unlock(p, lock);
++	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
++	if (pi)
++		cpuset_read_unlock();
++	return retval;
++}
++
++static int _sched_setscheduler(struct task_struct *p, int policy,
++			       const struct sched_param *param, bool check)
++{
++	struct sched_attr attr = {
++		.sched_policy   = policy,
++		.sched_priority = param->sched_priority,
++		.sched_nice     = PRIO_TO_NICE(p->static_prio),
++	};
++
++	/* Fixup the legacy SCHED_RESET_ON_FORK hack. */
++	if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
++		attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
++		policy &= ~SCHED_RESET_ON_FORK;
++		attr.sched_policy = policy;
++	}
++
++	return __sched_setscheduler(p, &attr, check, true);
++}
++
++/**
++ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
++ * @p: the task in question.
++ * @policy: new policy.
++ * @param: structure containing the new RT priority.
++ *
++ * Use sched_set_fifo(), read its comment.
++ *
++ * Return: 0 on success. An error code otherwise.
++ *
++ * NOTE that the task may be already dead.
++ */
++int sched_setscheduler(struct task_struct *p, int policy,
++		       const struct sched_param *param)
++{
++	return _sched_setscheduler(p, policy, param, true);
++}
++
++int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
++{
++	return __sched_setscheduler(p, attr, true, true);
++}
++
++int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
++{
++	return __sched_setscheduler(p, attr, false, true);
++}
++EXPORT_SYMBOL_GPL(sched_setattr_nocheck);
++
++/**
++ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
++ * @p: the task in question.
++ * @policy: new policy.
++ * @param: structure containing the new RT priority.
++ *
++ * Just like sched_setscheduler, only don't bother checking if the
++ * current context has permission.  For example, this is needed in
++ * stop_machine(): we create temporary high priority worker threads,
++ * but our caller might not have that capability.
++ *
++ * Return: 0 on success. An error code otherwise.
++ */
++int sched_setscheduler_nocheck(struct task_struct *p, int policy,
++			       const struct sched_param *param)
++{
++	return _sched_setscheduler(p, policy, param, false);
++}
++
++/*
++ * SCHED_FIFO is a broken scheduler model; that is, it is fundamentally
++ * incapable of resource management, which is the one thing an OS really should
++ * be doing.
++ *
++ * This is of course the reason it is limited to privileged users only.
++ *
++ * Worse still; it is fundamentally impossible to compose static priority
++ * workloads. You cannot take two correctly working static prio workloads
++ * and smash them together and still expect them to work.
++ *
++ * For this reason 'all' FIFO tasks the kernel creates are basically at:
++ *
++ *   MAX_RT_PRIO / 2
++ *
++ * The administrator _MUST_ configure the system, the kernel simply doesn't
++ * know enough information to make a sensible choice.
++ */
++void sched_set_fifo(struct task_struct *p)
++{
++	struct sched_param sp = { .sched_priority = MAX_RT_PRIO / 2 };
++	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
++}
++EXPORT_SYMBOL_GPL(sched_set_fifo);
++
++/*
++ * For when you don't much care about FIFO, but want to be above SCHED_NORMAL.
++ */
++void sched_set_fifo_low(struct task_struct *p)
++{
++	struct sched_param sp = { .sched_priority = 1 };
++	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
++}
++EXPORT_SYMBOL_GPL(sched_set_fifo_low);
++
++void sched_set_normal(struct task_struct *p, int nice)
++{
++	struct sched_attr attr = {
++		.sched_policy = SCHED_NORMAL,
++		.sched_nice = nice,
++	};
++	WARN_ON_ONCE(sched_setattr_nocheck(p, &attr) != 0);
++}
++EXPORT_SYMBOL_GPL(sched_set_normal);
++
++static int
++do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
++{
++	struct sched_param lparam;
++	struct task_struct *p;
++	int retval;
++
++	if (!param || pid < 0)
++		return -EINVAL;
++	if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
++		return -EFAULT;
++
++	rcu_read_lock();
++	retval = -ESRCH;
++	p = find_process_by_pid(pid);
++	if (likely(p))
++		get_task_struct(p);
++	rcu_read_unlock();
++
++	if (likely(p)) {
++		retval = sched_setscheduler(p, policy, &lparam);
++		put_task_struct(p);
++	}
++
++	return retval;
++}
++
++/*
++ * Mimics kernel/events/core.c perf_copy_attr().
++ */
++static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *attr)
++{
++	u32 size;
++	int ret;
++
++	/* Zero the full structure, so that a short copy will be nice: */
++	memset(attr, 0, sizeof(*attr));
++
++	ret = get_user(size, &uattr->size);
++	if (ret)
++		return ret;
++
++	/* ABI compatibility quirk: */
++	if (!size)
++		size = SCHED_ATTR_SIZE_VER0;
++
++	if (size < SCHED_ATTR_SIZE_VER0 || size > PAGE_SIZE)
++		goto err_size;
++
++	ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
++	if (ret) {
++		if (ret == -E2BIG)
++			goto err_size;
++		return ret;
++	}
++
++	/*
++	 * XXX: Do we want to be lenient like existing syscalls; or do we want
++	 * to be strict and return an error on out-of-bounds values?
++	 */
++	attr->sched_nice = clamp(attr->sched_nice, -20, 19);
++
++	/* sched/core.c uses zero here but we already know ret is zero */
++	return 0;
++
++err_size:
++	put_user(sizeof(*attr), &uattr->size);
++	return -E2BIG;
++}
++
++/**
++ * sys_sched_setscheduler - set/change the scheduler policy and RT priority
++ * @pid: the pid in question.
++ * @policy: new policy.
++ *
++ * Return: 0 on success. An error code otherwise.
++ * @param: structure containing the new RT priority.
++ */
++SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param)
++{
++	if (policy < 0)
++		return -EINVAL;
++
++	return do_sched_setscheduler(pid, policy, param);
++}
++
++/**
++ * sys_sched_setparam - set/change the RT priority of a thread
++ * @pid: the pid in question.
++ * @param: structure containing the new RT priority.
++ *
++ * Return: 0 on success. An error code otherwise.
++ */
++SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
++{
++	return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
++}
++
++/**
++ * sys_sched_setattr - same as above, but with extended sched_attr
++ * @pid: the pid in question.
++ * @uattr: structure containing the extended parameters.
++ */
++SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
++			       unsigned int, flags)
++{
++	struct sched_attr attr;
++	struct task_struct *p;
++	int retval;
++
++	if (!uattr || pid < 0 || flags)
++		return -EINVAL;
++
++	retval = sched_copy_attr(uattr, &attr);
++	if (retval)
++		return retval;
++
++	if ((int)attr.sched_policy < 0)
++		return -EINVAL;
++
++	rcu_read_lock();
++	retval = -ESRCH;
++	p = find_process_by_pid(pid);
++	if (likely(p))
++		get_task_struct(p);
++	rcu_read_unlock();
++
++	if (likely(p)) {
++		retval = sched_setattr(p, &attr);
++		put_task_struct(p);
++	}
++
++	return retval;
++}
++
++/**
++ * sys_sched_getscheduler - get the policy (scheduling class) of a thread
++ * @pid: the pid in question.
++ *
++ * Return: On success, the policy of the thread. Otherwise, a negative error
++ * code.
++ */
++SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
++{
++	struct task_struct *p;
++	int retval = -EINVAL;
++
++	if (pid < 0)
++		goto out_nounlock;
++
++	retval = -ESRCH;
++	rcu_read_lock();
++	p = find_process_by_pid(pid);
++	if (p) {
++		retval = security_task_getscheduler(p);
++		if (!retval)
++			retval = p->policy;
++	}
++	rcu_read_unlock();
++
++out_nounlock:
++	return retval;
++}
++
++/**
++ * sys_sched_getscheduler - get the RT priority of a thread
++ * @pid: the pid in question.
++ * @param: structure containing the RT priority.
++ *
++ * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
++ * code.
++ */
++SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
++{
++	struct sched_param lp = { .sched_priority = 0 };
++	struct task_struct *p;
++	int retval = -EINVAL;
++
++	if (!param || pid < 0)
++		goto out_nounlock;
++
++	rcu_read_lock();
++	p = find_process_by_pid(pid);
++	retval = -ESRCH;
++	if (!p)
++		goto out_unlock;
++
++	retval = security_task_getscheduler(p);
++	if (retval)
++		goto out_unlock;
++
++	if (task_has_rt_policy(p))
++		lp.sched_priority = p->rt_priority;
++	rcu_read_unlock();
++
++	/*
++	 * This one might sleep, we cannot do it with a spinlock held ...
++	 */
++	retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
++
++out_nounlock:
++	return retval;
++
++out_unlock:
++	rcu_read_unlock();
++	return retval;
++}
++
++/*
++ * Copy the kernel size attribute structure (which might be larger
++ * than what user-space knows about) to user-space.
++ *
++ * Note that all cases are valid: user-space buffer can be larger or
++ * smaller than the kernel-space buffer. The usual case is that both
++ * have the same size.
++ */
++static int
++sched_attr_copy_to_user(struct sched_attr __user *uattr,
++			struct sched_attr *kattr,
++			unsigned int usize)
++{
++	unsigned int ksize = sizeof(*kattr);
++
++	if (!access_ok(uattr, usize))
++		return -EFAULT;
++
++	/*
++	 * sched_getattr() ABI forwards and backwards compatibility:
++	 *
++	 * If usize == ksize then we just copy everything to user-space and all is good.
++	 *
++	 * If usize < ksize then we only copy as much as user-space has space for,
++	 * this keeps ABI compatibility as well. We skip the rest.
++	 *
++	 * If usize > ksize then user-space is using a newer version of the ABI,
++	 * which part the kernel doesn't know about. Just ignore it - tooling can
++	 * detect the kernel's knowledge of attributes from the attr->size value
++	 * which is set to ksize in this case.
++	 */
++	kattr->size = min(usize, ksize);
++
++	if (copy_to_user(uattr, kattr, kattr->size))
++		return -EFAULT;
++
++	return 0;
++}
++
++/**
++ * sys_sched_getattr - similar to sched_getparam, but with sched_attr
++ * @pid: the pid in question.
++ * @uattr: structure containing the extended parameters.
++ * @usize: sizeof(attr) for fwd/bwd comp.
++ * @flags: for future extension.
++ */
++SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
++		unsigned int, usize, unsigned int, flags)
++{
++	struct sched_attr kattr = { };
++	struct task_struct *p;
++	int retval;
++
++	if (!uattr || pid < 0 || usize > PAGE_SIZE ||
++	    usize < SCHED_ATTR_SIZE_VER0 || flags)
++		return -EINVAL;
++
++	rcu_read_lock();
++	p = find_process_by_pid(pid);
++	retval = -ESRCH;
++	if (!p)
++		goto out_unlock;
++
++	retval = security_task_getscheduler(p);
++	if (retval)
++		goto out_unlock;
++
++	kattr.sched_policy = p->policy;
++	if (p->sched_reset_on_fork)
++		kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
++	if (task_has_rt_policy(p))
++		kattr.sched_priority = p->rt_priority;
++	else
++		kattr.sched_nice = task_nice(p);
++	kattr.sched_flags &= SCHED_FLAG_ALL;
++
++#ifdef CONFIG_UCLAMP_TASK
++	kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value;
++	kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value;
++#endif
++
++	rcu_read_unlock();
++
++	return sched_attr_copy_to_user(uattr, &kattr, usize);
++
++out_unlock:
++	rcu_read_unlock();
++	return retval;
++}
++
++static int
++__sched_setaffinity(struct task_struct *p, const struct cpumask *mask)
++{
++	int retval;
++	cpumask_var_t cpus_allowed, new_mask;
++
++	if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL))
++		return -ENOMEM;
++
++	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
++		retval = -ENOMEM;
++		goto out_free_cpus_allowed;
++	}
++
++	cpuset_cpus_allowed(p, cpus_allowed);
++	cpumask_and(new_mask, mask, cpus_allowed);
++again:
++	retval = __set_cpus_allowed_ptr(p, new_mask, SCA_CHECK | SCA_USER);
++	if (retval)
++		goto out_free_new_mask;
++
++	cpuset_cpus_allowed(p, cpus_allowed);
++	if (!cpumask_subset(new_mask, cpus_allowed)) {
++		/*
++		 * We must have raced with a concurrent cpuset
++		 * update. Just reset the cpus_allowed to the
++		 * cpuset's cpus_allowed
++		 */
++		cpumask_copy(new_mask, cpus_allowed);
++		goto again;
++	}
++
++out_free_new_mask:
++	free_cpumask_var(new_mask);
++out_free_cpus_allowed:
++	free_cpumask_var(cpus_allowed);
++	return retval;
++}
++
++long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
++{
++	struct task_struct *p;
++	int retval;
++
++	rcu_read_lock();
++
++	p = find_process_by_pid(pid);
++	if (!p) {
++		rcu_read_unlock();
++		return -ESRCH;
++	}
++
++	/* Prevent p going away */
++	get_task_struct(p);
++	rcu_read_unlock();
++
++	if (p->flags & PF_NO_SETAFFINITY) {
++		retval = -EINVAL;
++		goto out_put_task;
++	}
++
++	if (!check_same_owner(p)) {
++		rcu_read_lock();
++		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
++			rcu_read_unlock();
++			retval = -EPERM;
++			goto out_put_task;
++		}
++		rcu_read_unlock();
++	}
++
++	retval = security_task_setscheduler(p);
++	if (retval)
++		goto out_put_task;
++
++	retval = __sched_setaffinity(p, in_mask);
++out_put_task:
++	put_task_struct(p);
++	return retval;
++}
++
++static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
++			     struct cpumask *new_mask)
++{
++	if (len < cpumask_size())
++		cpumask_clear(new_mask);
++	else if (len > cpumask_size())
++		len = cpumask_size();
++
++	return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
++}
++
++/**
++ * sys_sched_setaffinity - set the CPU affinity of a process
++ * @pid: pid of the process
++ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
++ * @user_mask_ptr: user-space pointer to the new CPU mask
++ *
++ * Return: 0 on success. An error code otherwise.
++ */
++SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
++		unsigned long __user *, user_mask_ptr)
++{
++	cpumask_var_t new_mask;
++	int retval;
++
++	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
++		return -ENOMEM;
++
++	retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
++	if (retval == 0)
++		retval = sched_setaffinity(pid, new_mask);
++	free_cpumask_var(new_mask);
++	return retval;
++}
++
++long sched_getaffinity(pid_t pid, cpumask_t *mask)
++{
++	struct task_struct *p;
++	raw_spinlock_t *lock;
++	unsigned long flags;
++	int retval;
++
++	rcu_read_lock();
++
++	retval = -ESRCH;
++	p = find_process_by_pid(pid);
++	if (!p)
++		goto out_unlock;
++
++	retval = security_task_getscheduler(p);
++	if (retval)
++		goto out_unlock;
++
++	task_access_lock_irqsave(p, &lock, &flags);
++	cpumask_and(mask, &p->cpus_mask, cpu_active_mask);
++	task_access_unlock_irqrestore(p, lock, &flags);
++
++out_unlock:
++	rcu_read_unlock();
++
++	return retval;
++}
++
++/**
++ * sys_sched_getaffinity - get the CPU affinity of a process
++ * @pid: pid of the process
++ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
++ * @user_mask_ptr: user-space pointer to hold the current CPU mask
++ *
++ * Return: size of CPU mask copied to user_mask_ptr on success. An
++ * error code otherwise.
++ */
++SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
++		unsigned long __user *, user_mask_ptr)
++{
++	int ret;
++	cpumask_var_t mask;
++
++	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
++		return -EINVAL;
++	if (len & (sizeof(unsigned long)-1))
++		return -EINVAL;
++
++	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
++		return -ENOMEM;
++
++	ret = sched_getaffinity(pid, mask);
++	if (ret == 0) {
++		unsigned int retlen = min_t(size_t, len, cpumask_size());
++
++		if (copy_to_user(user_mask_ptr, mask, retlen))
++			ret = -EFAULT;
++		else
++			ret = retlen;
++	}
++	free_cpumask_var(mask);
++
++	return ret;
++}
++
++static void do_sched_yield(void)
++{
++	struct rq *rq;
++	struct rq_flags rf;
++
++	if (!sched_yield_type)
++		return;
++
++	rq = this_rq_lock_irq(&rf);
++
++	schedstat_inc(rq->yld_count);
++
++	if (1 == sched_yield_type) {
++		if (!rt_task(current))
++			do_sched_yield_type_1(current, rq);
++	} else if (2 == sched_yield_type) {
++		if (rq->nr_running > 1)
++			rq->skip = current;
++	}
++
++	preempt_disable();
++	raw_spin_unlock_irq(&rq->lock);
++	sched_preempt_enable_no_resched();
++
++	schedule();
++}
++
++/**
++ * sys_sched_yield - yield the current processor to other threads.
++ *
++ * This function yields the current CPU to other tasks. If there are no
++ * other threads running on this CPU then this function will return.
++ *
++ * Return: 0.
++ */
++SYSCALL_DEFINE0(sched_yield)
++{
++	do_sched_yield();
++	return 0;
++}
++
++#if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC)
++int __sched __cond_resched(void)
++{
++	if (should_resched(0)) {
++		preempt_schedule_common();
++		return 1;
++	}
++	/*
++	 * In preemptible kernels, ->rcu_read_lock_nesting tells the tick
++	 * whether the current CPU is in an RCU read-side critical section,
++	 * so the tick can report quiescent states even for CPUs looping
++	 * in kernel context.  In contrast, in non-preemptible kernels,
++	 * RCU readers leave no in-memory hints, which means that CPU-bound
++	 * processes executing in kernel context might never report an
++	 * RCU quiescent state.  Therefore, the following code causes
++	 * cond_resched() to report a quiescent state, but only when RCU
++	 * is in urgent need of one.
++	 */
++#ifndef CONFIG_PREEMPT_RCU
++	rcu_all_qs();
++#endif
++	return 0;
++}
++EXPORT_SYMBOL(__cond_resched);
++#endif
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++DEFINE_STATIC_CALL_RET0(cond_resched, __cond_resched);
++EXPORT_STATIC_CALL_TRAMP(cond_resched);
++
++DEFINE_STATIC_CALL_RET0(might_resched, __cond_resched);
++EXPORT_STATIC_CALL_TRAMP(might_resched);
++#endif
++
++/*
++ * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
++ * call schedule, and on return reacquire the lock.
++ *
++ * This works OK both with and without CONFIG_PREEMPTION.  We do strange low-level
++ * operations here to prevent schedule() from being called twice (once via
++ * spin_unlock(), once by hand).
++ */
++int __cond_resched_lock(spinlock_t *lock)
++{
++	int resched = should_resched(PREEMPT_LOCK_OFFSET);
++	int ret = 0;
++
++	lockdep_assert_held(lock);
++
++	if (spin_needbreak(lock) || resched) {
++		spin_unlock(lock);
++		if (resched)
++			preempt_schedule_common();
++		else
++			cpu_relax();
++		ret = 1;
++		spin_lock(lock);
++	}
++	return ret;
++}
++EXPORT_SYMBOL(__cond_resched_lock);
++
++int __cond_resched_rwlock_read(rwlock_t *lock)
++{
++	int resched = should_resched(PREEMPT_LOCK_OFFSET);
++	int ret = 0;
++
++	lockdep_assert_held_read(lock);
++
++	if (rwlock_needbreak(lock) || resched) {
++		read_unlock(lock);
++		if (resched)
++			preempt_schedule_common();
++		else
++			cpu_relax();
++		ret = 1;
++		read_lock(lock);
++	}
++	return ret;
++}
++EXPORT_SYMBOL(__cond_resched_rwlock_read);
++
++int __cond_resched_rwlock_write(rwlock_t *lock)
++{
++	int resched = should_resched(PREEMPT_LOCK_OFFSET);
++	int ret = 0;
++
++	lockdep_assert_held_write(lock);
++
++	if (rwlock_needbreak(lock) || resched) {
++		write_unlock(lock);
++		if (resched)
++			preempt_schedule_common();
++		else
++			cpu_relax();
++		ret = 1;
++		write_lock(lock);
++	}
++	return ret;
++}
++EXPORT_SYMBOL(__cond_resched_rwlock_write);
++
++/**
++ * yield - yield the current processor to other threads.
++ *
++ * Do not ever use this function, there's a 99% chance you're doing it wrong.
++ *
++ * The scheduler is at all times free to pick the calling task as the most
++ * eligible task to run, if removing the yield() call from your code breaks
++ * it, it's already broken.
++ *
++ * Typical broken usage is:
++ *
++ * while (!event)
++ * 	yield();
++ *
++ * where one assumes that yield() will let 'the other' process run that will
++ * make event true. If the current task is a SCHED_FIFO task that will never
++ * happen. Never use yield() as a progress guarantee!!
++ *
++ * If you want to use yield() to wait for something, use wait_event().
++ * If you want to use yield() to be 'nice' for others, use cond_resched().
++ * If you still want to use yield(), do not!
++ */
++void __sched yield(void)
++{
++	set_current_state(TASK_RUNNING);
++	do_sched_yield();
++}
++EXPORT_SYMBOL(yield);
++
++/**
++ * yield_to - yield the current processor to another thread in
++ * your thread group, or accelerate that thread toward the
++ * processor it's on.
++ * @p: target task
++ * @preempt: whether task preemption is allowed or not
++ *
++ * It's the caller's job to ensure that the target task struct
++ * can't go away on us before we can do any checks.
++ *
++ * In Alt schedule FW, yield_to is not supported.
++ *
++ * Return:
++ *	true (>0) if we indeed boosted the target task.
++ *	false (0) if we failed to boost the target.
++ *	-ESRCH if there's no task to yield to.
++ */
++int __sched yield_to(struct task_struct *p, bool preempt)
++{
++	return 0;
++}
++EXPORT_SYMBOL_GPL(yield_to);
++
++int io_schedule_prepare(void)
++{
++	int old_iowait = current->in_iowait;
++
++	current->in_iowait = 1;
++	blk_schedule_flush_plug(current);
++
++	return old_iowait;
++}
++
++void io_schedule_finish(int token)
++{
++	current->in_iowait = token;
++}
++
++/*
++ * This task is about to go to sleep on IO.  Increment rq->nr_iowait so
++ * that process accounting knows that this is a task in IO wait state.
++ *
++ * But don't do that if it is a deliberate, throttling IO wait (this task
++ * has set its backing_dev_info: the queue against which it should throttle)
++ */
++
++long __sched io_schedule_timeout(long timeout)
++{
++	int token;
++	long ret;
++
++	token = io_schedule_prepare();
++	ret = schedule_timeout(timeout);
++	io_schedule_finish(token);
++
++	return ret;
++}
++EXPORT_SYMBOL(io_schedule_timeout);
++
++void __sched io_schedule(void)
++{
++	int token;
++
++	token = io_schedule_prepare();
++	schedule();
++	io_schedule_finish(token);
++}
++EXPORT_SYMBOL(io_schedule);
++
++/**
++ * sys_sched_get_priority_max - return maximum RT priority.
++ * @policy: scheduling class.
++ *
++ * Return: On success, this syscall returns the maximum
++ * rt_priority that can be used by a given scheduling class.
++ * On failure, a negative error code is returned.
++ */
++SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
++{
++	int ret = -EINVAL;
++
++	switch (policy) {
++	case SCHED_FIFO:
++	case SCHED_RR:
++		ret = MAX_RT_PRIO - 1;
++		break;
++	case SCHED_NORMAL:
++	case SCHED_BATCH:
++	case SCHED_IDLE:
++		ret = 0;
++		break;
++	}
++	return ret;
++}
++
++/**
++ * sys_sched_get_priority_min - return minimum RT priority.
++ * @policy: scheduling class.
++ *
++ * Return: On success, this syscall returns the minimum
++ * rt_priority that can be used by a given scheduling class.
++ * On failure, a negative error code is returned.
++ */
++SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
++{
++	int ret = -EINVAL;
++
++	switch (policy) {
++	case SCHED_FIFO:
++	case SCHED_RR:
++		ret = 1;
++		break;
++	case SCHED_NORMAL:
++	case SCHED_BATCH:
++	case SCHED_IDLE:
++		ret = 0;
++		break;
++	}
++	return ret;
++}
++
++static int sched_rr_get_interval(pid_t pid, struct timespec64 *t)
++{
++	struct task_struct *p;
++	int retval;
++
++	alt_sched_debug();
++
++	if (pid < 0)
++		return -EINVAL;
++
++	retval = -ESRCH;
++	rcu_read_lock();
++	p = find_process_by_pid(pid);
++	if (!p)
++		goto out_unlock;
++
++	retval = security_task_getscheduler(p);
++	if (retval)
++		goto out_unlock;
++	rcu_read_unlock();
++
++	*t = ns_to_timespec64(sched_timeslice_ns);
++	return 0;
++
++out_unlock:
++	rcu_read_unlock();
++	return retval;
++}
++
++/**
++ * sys_sched_rr_get_interval - return the default timeslice of a process.
++ * @pid: pid of the process.
++ * @interval: userspace pointer to the timeslice value.
++ *
++ *
++ * Return: On success, 0 and the timeslice is in @interval. Otherwise,
++ * an error code.
++ */
++SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
++		struct __kernel_timespec __user *, interval)
++{
++	struct timespec64 t;
++	int retval = sched_rr_get_interval(pid, &t);
++
++	if (retval == 0)
++		retval = put_timespec64(&t, interval);
++
++	return retval;
++}
++
++#ifdef CONFIG_COMPAT_32BIT_TIME
++SYSCALL_DEFINE2(sched_rr_get_interval_time32, pid_t, pid,
++		struct old_timespec32 __user *, interval)
++{
++	struct timespec64 t;
++	int retval = sched_rr_get_interval(pid, &t);
++
++	if (retval == 0)
++		retval = put_old_timespec32(&t, interval);
++	return retval;
++}
++#endif
++
++void sched_show_task(struct task_struct *p)
++{
++	unsigned long free = 0;
++	int ppid;
++
++	if (!try_get_task_stack(p))
++		return;
++
++	pr_info("task:%-15.15s state:%c", p->comm, task_state_to_char(p));
++
++	if (task_is_running(p))
++		pr_cont("  running task    ");
++#ifdef CONFIG_DEBUG_STACK_USAGE
++	free = stack_not_used(p);
++#endif
++	ppid = 0;
++	rcu_read_lock();
++	if (pid_alive(p))
++		ppid = task_pid_nr(rcu_dereference(p->real_parent));
++	rcu_read_unlock();
++	pr_cont(" stack:%5lu pid:%5d ppid:%6d flags:0x%08lx\n",
++		free, task_pid_nr(p), ppid,
++		(unsigned long)task_thread_info(p)->flags);
++
++	print_worker_info(KERN_INFO, p);
++	print_stop_info(KERN_INFO, p);
++	show_stack(p, NULL, KERN_INFO);
++	put_task_stack(p);
++}
++EXPORT_SYMBOL_GPL(sched_show_task);
++
++static inline bool
++state_filter_match(unsigned long state_filter, struct task_struct *p)
++{
++	unsigned int state = READ_ONCE(p->__state);
++
++	/* no filter, everything matches */
++	if (!state_filter)
++		return true;
++
++	/* filter, but doesn't match */
++	if (!(state & state_filter))
++		return false;
++
++	/*
++	 * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
++	 * TASK_KILLABLE).
++	 */
++	if (state_filter == TASK_UNINTERRUPTIBLE && state == TASK_IDLE)
++		return false;
++
++	return true;
++}
++
++
++void show_state_filter(unsigned int state_filter)
++{
++	struct task_struct *g, *p;
++
++	rcu_read_lock();
++	for_each_process_thread(g, p) {
++		/*
++		 * reset the NMI-timeout, listing all files on a slow
++		 * console might take a lot of time:
++		 * Also, reset softlockup watchdogs on all CPUs, because
++		 * another CPU might be blocked waiting for us to process
++		 * an IPI.
++		 */
++		touch_nmi_watchdog();
++		touch_all_softlockup_watchdogs();
++		if (state_filter_match(state_filter, p))
++			sched_show_task(p);
++	}
++
++#ifdef CONFIG_SCHED_DEBUG
++	/* TODO: Alt schedule FW should support this
++	if (!state_filter)
++		sysrq_sched_debug_show();
++	*/
++#endif
++	rcu_read_unlock();
++	/*
++	 * Only show locks if all tasks are dumped:
++	 */
++	if (!state_filter)
++		debug_show_all_locks();
++}
++
++void dump_cpu_task(int cpu)
++{
++	pr_info("Task dump for CPU %d:\n", cpu);
++	sched_show_task(cpu_curr(cpu));
++}
++
++/**
++ * init_idle - set up an idle thread for a given CPU
++ * @idle: task in question
++ * @cpu: CPU the idle task belongs to
++ *
++ * NOTE: this function does not set the idle thread's NEED_RESCHED
++ * flag, to make booting more robust.
++ */
++void __init init_idle(struct task_struct *idle, int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++	unsigned long flags;
++
++	__sched_fork(0, idle);
++
++	/*
++	 * The idle task doesn't need the kthread struct to function, but it
++	 * is dressed up as a per-CPU kthread and thus needs to play the part
++	 * if we want to avoid special-casing it in code that deals with per-CPU
++	 * kthreads.
++	 */
++	set_kthread_struct(idle);
++
++	raw_spin_lock_irqsave(&idle->pi_lock, flags);
++	raw_spin_lock(&rq->lock);
++	update_rq_clock(rq);
++
++	idle->last_ran = rq->clock_task;
++	idle->__state = TASK_RUNNING;
++	/*
++	 * PF_KTHREAD should already be set at this point; regardless, make it
++	 * look like a proper per-CPU kthread.
++	 */
++	idle->flags |= PF_IDLE | PF_KTHREAD | PF_NO_SETAFFINITY;
++	kthread_set_per_cpu(idle, cpu);
++
++	sched_queue_init_idle(&rq->queue, idle);
++
++	scs_task_reset(idle);
++	kasan_unpoison_task_stack(idle);
++
++#ifdef CONFIG_SMP
++	/*
++	 * It's possible that init_idle() gets called multiple times on a task,
++	 * in that case do_set_cpus_allowed() will not do the right thing.
++	 *
++	 * And since this is boot we can forgo the serialisation.
++	 */
++	set_cpus_allowed_common(idle, cpumask_of(cpu));
++#endif
++
++	/* Silence PROVE_RCU */
++	rcu_read_lock();
++	__set_task_cpu(idle, cpu);
++	rcu_read_unlock();
++
++	rq->idle = idle;
++	rcu_assign_pointer(rq->curr, idle);
++	idle->on_cpu = 1;
++
++	raw_spin_unlock(&rq->lock);
++	raw_spin_unlock_irqrestore(&idle->pi_lock, flags);
++
++	/* Set the preempt count _outside_ the spinlocks! */
++	init_idle_preempt_count(idle, cpu);
++
++	ftrace_graph_init_idle_task(idle, cpu);
++	vtime_init_idle(idle, cpu);
++#ifdef CONFIG_SMP
++	sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
++#endif
++}
++
++#ifdef CONFIG_SMP
++
++int cpuset_cpumask_can_shrink(const struct cpumask __maybe_unused *cur,
++			      const struct cpumask __maybe_unused *trial)
++{
++	return 1;
++}
++
++int task_can_attach(struct task_struct *p,
++		    const struct cpumask *cs_cpus_allowed)
++{
++	int ret = 0;
++
++	/*
++	 * Kthreads which disallow setaffinity shouldn't be moved
++	 * to a new cpuset; we don't want to change their CPU
++	 * affinity and isolating such threads by their set of
++	 * allowed nodes is unnecessary.  Thus, cpusets are not
++	 * applicable for such threads.  This prevents checking for
++	 * success of set_cpus_allowed_ptr() on all attached tasks
++	 * before cpus_mask may be changed.
++	 */
++	if (p->flags & PF_NO_SETAFFINITY)
++		ret = -EINVAL;
++
++	return ret;
++}
++
++bool sched_smp_initialized __read_mostly;
++
++#ifdef CONFIG_HOTPLUG_CPU
++/*
++ * Ensures that the idle task is using init_mm right before its CPU goes
++ * offline.
++ */
++void idle_task_exit(void)
++{
++	struct mm_struct *mm = current->active_mm;
++
++	BUG_ON(current != this_rq()->idle);
++
++	if (mm != &init_mm) {
++		switch_mm(mm, &init_mm, current);
++		finish_arch_post_lock_switch();
++	}
++
++	scs_task_reset(current);
++	/* finish_cpu(), as ran on the BP, will clean up the active_mm state */
++}
++
++static int __balance_push_cpu_stop(void *arg)
++{
++	struct task_struct *p = arg;
++	struct rq *rq = this_rq();
++	struct rq_flags rf;
++	int cpu;
++
++	raw_spin_lock_irq(&p->pi_lock);
++	rq_lock(rq, &rf);
++
++	update_rq_clock(rq);
++
++	if (task_rq(p) == rq && task_on_rq_queued(p)) {
++		cpu = select_fallback_rq(rq->cpu, p);
++		rq = __migrate_task(rq, p, cpu);
++	}
++
++	rq_unlock(rq, &rf);
++	raw_spin_unlock_irq(&p->pi_lock);
++
++	put_task_struct(p);
++
++	return 0;
++}
++
++static DEFINE_PER_CPU(struct cpu_stop_work, push_work);
++
++/*
++ * This is enabled below SCHED_AP_ACTIVE; when !cpu_active(), but only
++ * effective when the hotplug motion is down.
++ */
++static void balance_push(struct rq *rq)
++{
++	struct task_struct *push_task = rq->curr;
++
++	lockdep_assert_held(&rq->lock);
++
++	/*
++	 * Ensure the thing is persistent until balance_push_set(.on = false);
++	 */
++	rq->balance_callback = &balance_push_callback;
++
++	/*
++	 * Only active while going offline and when invoked on the outgoing
++	 * CPU.
++	 */
++	if (!cpu_dying(rq->cpu) || rq != this_rq())
++		return;
++
++	/*
++	 * Both the cpu-hotplug and stop task are in this case and are
++	 * required to complete the hotplug process.
++	 */
++	if (kthread_is_per_cpu(push_task) ||
++	    is_migration_disabled(push_task)) {
++
++		/*
++		 * If this is the idle task on the outgoing CPU try to wake
++		 * up the hotplug control thread which might wait for the
++		 * last task to vanish. The rcuwait_active() check is
++		 * accurate here because the waiter is pinned on this CPU
++		 * and can't obviously be running in parallel.
++		 *
++		 * On RT kernels this also has to check whether there are
++		 * pinned and scheduled out tasks on the runqueue. They
++		 * need to leave the migrate disabled section first.
++		 */
++		if (!rq->nr_running && !rq_has_pinned_tasks(rq) &&
++		    rcuwait_active(&rq->hotplug_wait)) {
++			raw_spin_unlock(&rq->lock);
++			rcuwait_wake_up(&rq->hotplug_wait);
++			raw_spin_lock(&rq->lock);
++		}
++		return;
++	}
++
++	get_task_struct(push_task);
++	/*
++	 * Temporarily drop rq->lock such that we can wake-up the stop task.
++	 * Both preemption and IRQs are still disabled.
++	 */
++	raw_spin_unlock(&rq->lock);
++	stop_one_cpu_nowait(rq->cpu, __balance_push_cpu_stop, push_task,
++			    this_cpu_ptr(&push_work));
++	/*
++	 * At this point need_resched() is true and we'll take the loop in
++	 * schedule(). The next pick is obviously going to be the stop task
++	 * which kthread_is_per_cpu() and will push this task away.
++	 */
++	raw_spin_lock(&rq->lock);
++}
++
++static void balance_push_set(int cpu, bool on)
++{
++	struct rq *rq = cpu_rq(cpu);
++	struct rq_flags rf;
++
++	rq_lock_irqsave(rq, &rf);
++	if (on) {
++		WARN_ON_ONCE(rq->balance_callback);
++		rq->balance_callback = &balance_push_callback;
++	} else if (rq->balance_callback == &balance_push_callback) {
++		rq->balance_callback = NULL;
++	}
++	rq_unlock_irqrestore(rq, &rf);
++}
++
++/*
++ * Invoked from a CPUs hotplug control thread after the CPU has been marked
++ * inactive. All tasks which are not per CPU kernel threads are either
++ * pushed off this CPU now via balance_push() or placed on a different CPU
++ * during wakeup. Wait until the CPU is quiescent.
++ */
++static void balance_hotplug_wait(void)
++{
++	struct rq *rq = this_rq();
++
++	rcuwait_wait_event(&rq->hotplug_wait,
++			   rq->nr_running == 1 && !rq_has_pinned_tasks(rq),
++			   TASK_UNINTERRUPTIBLE);
++}
++
++#else
++
++static void balance_push(struct rq *rq)
++{
++}
++
++static void balance_push_set(int cpu, bool on)
++{
++}
++
++static inline void balance_hotplug_wait(void)
++{
++}
++#endif /* CONFIG_HOTPLUG_CPU */
++
++static void set_rq_offline(struct rq *rq)
++{
++	if (rq->online)
++		rq->online = false;
++}
++
++static void set_rq_online(struct rq *rq)
++{
++	if (!rq->online)
++		rq->online = true;
++}
++
++/*
++ * used to mark begin/end of suspend/resume:
++ */
++static int num_cpus_frozen;
++
++/*
++ * Update cpusets according to cpu_active mask.  If cpusets are
++ * disabled, cpuset_update_active_cpus() becomes a simple wrapper
++ * around partition_sched_domains().
++ *
++ * If we come here as part of a suspend/resume, don't touch cpusets because we
++ * want to restore it back to its original state upon resume anyway.
++ */
++static void cpuset_cpu_active(void)
++{
++	if (cpuhp_tasks_frozen) {
++		/*
++		 * num_cpus_frozen tracks how many CPUs are involved in suspend
++		 * resume sequence. As long as this is not the last online
++		 * operation in the resume sequence, just build a single sched
++		 * domain, ignoring cpusets.
++		 */
++		partition_sched_domains(1, NULL, NULL);
++		if (--num_cpus_frozen)
++			return;
++		/*
++		 * This is the last CPU online operation. So fall through and
++		 * restore the original sched domains by considering the
++		 * cpuset configurations.
++		 */
++		cpuset_force_rebuild();
++	}
++
++	cpuset_update_active_cpus();
++}
++
++static int cpuset_cpu_inactive(unsigned int cpu)
++{
++	if (!cpuhp_tasks_frozen) {
++		cpuset_update_active_cpus();
++	} else {
++		num_cpus_frozen++;
++		partition_sched_domains(1, NULL, NULL);
++	}
++	return 0;
++}
++
++int sched_cpu_activate(unsigned int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++	unsigned long flags;
++
++	/*
++	 * Clear the balance_push callback and prepare to schedule
++	 * regular tasks.
++	 */
++	balance_push_set(cpu, false);
++
++#ifdef CONFIG_SCHED_SMT
++	/*
++	 * When going up, increment the number of cores with SMT present.
++	 */
++	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
++		static_branch_inc_cpuslocked(&sched_smt_present);
++#endif
++	set_cpu_active(cpu, true);
++
++	if (sched_smp_initialized)
++		cpuset_cpu_active();
++
++	/*
++	 * Put the rq online, if not already. This happens:
++	 *
++	 * 1) In the early boot process, because we build the real domains
++	 *    after all cpus have been brought up.
++	 *
++	 * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
++	 *    domains.
++	 */
++	raw_spin_lock_irqsave(&rq->lock, flags);
++	set_rq_online(rq);
++	raw_spin_unlock_irqrestore(&rq->lock, flags);
++
++	return 0;
++}
++
++int sched_cpu_deactivate(unsigned int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++	unsigned long flags;
++	int ret;
++
++	set_cpu_active(cpu, false);
++
++	/*
++	 * From this point forward, this CPU will refuse to run any task that
++	 * is not: migrate_disable() or KTHREAD_IS_PER_CPU, and will actively
++	 * push those tasks away until this gets cleared, see
++	 * sched_cpu_dying().
++	 */
++	balance_push_set(cpu, true);
++
++	/*
++	 * We've cleared cpu_active_mask, wait for all preempt-disabled and RCU
++	 * users of this state to go away such that all new such users will
++	 * observe it.
++	 *
++	 * Specifically, we rely on ttwu to no longer target this CPU, see
++	 * ttwu_queue_cond() and is_cpu_allowed().
++	 *
++	 * Do sync before park smpboot threads to take care the rcu boost case.
++	 */
++	synchronize_rcu();
++
++	raw_spin_lock_irqsave(&rq->lock, flags);
++	update_rq_clock(rq);
++	set_rq_offline(rq);
++	raw_spin_unlock_irqrestore(&rq->lock, flags);
++
++#ifdef CONFIG_SCHED_SMT
++	/*
++	 * When going down, decrement the number of cores with SMT present.
++	 */
++	if (cpumask_weight(cpu_smt_mask(cpu)) == 2) {
++		static_branch_dec_cpuslocked(&sched_smt_present);
++		if (!static_branch_likely(&sched_smt_present))
++			cpumask_clear(&sched_sg_idle_mask);
++	}
++#endif
++
++	if (!sched_smp_initialized)
++		return 0;
++
++	ret = cpuset_cpu_inactive(cpu);
++	if (ret) {
++		balance_push_set(cpu, false);
++		set_cpu_active(cpu, true);
++		return ret;
++	}
++
++	return 0;
++}
++
++static void sched_rq_cpu_starting(unsigned int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++
++	rq->calc_load_update = calc_load_update;
++}
++
++int sched_cpu_starting(unsigned int cpu)
++{
++	sched_rq_cpu_starting(cpu);
++	sched_tick_start(cpu);
++	return 0;
++}
++
++#ifdef CONFIG_HOTPLUG_CPU
++
++/*
++ * Invoked immediately before the stopper thread is invoked to bring the
++ * CPU down completely. At this point all per CPU kthreads except the
++ * hotplug thread (current) and the stopper thread (inactive) have been
++ * either parked or have been unbound from the outgoing CPU. Ensure that
++ * any of those which might be on the way out are gone.
++ *
++ * If after this point a bound task is being woken on this CPU then the
++ * responsible hotplug callback has failed to do it's job.
++ * sched_cpu_dying() will catch it with the appropriate fireworks.
++ */
++int sched_cpu_wait_empty(unsigned int cpu)
++{
++	balance_hotplug_wait();
++	return 0;
++}
++
++/*
++ * Since this CPU is going 'away' for a while, fold any nr_active delta we
++ * might have. Called from the CPU stopper task after ensuring that the
++ * stopper is the last running task on the CPU, so nr_active count is
++ * stable. We need to take the teardown thread which is calling this into
++ * account, so we hand in adjust = 1 to the load calculation.
++ *
++ * Also see the comment "Global load-average calculations".
++ */
++static void calc_load_migrate(struct rq *rq)
++{
++	long delta = calc_load_fold_active(rq, 1);
++
++	if (delta)
++		atomic_long_add(delta, &calc_load_tasks);
++}
++
++static void dump_rq_tasks(struct rq *rq, const char *loglvl)
++{
++	struct task_struct *g, *p;
++	int cpu = cpu_of(rq);
++
++	lockdep_assert_held(&rq->lock);
++
++	printk("%sCPU%d enqueued tasks (%u total):\n", loglvl, cpu, rq->nr_running);
++	for_each_process_thread(g, p) {
++		if (task_cpu(p) != cpu)
++			continue;
++
++		if (!task_on_rq_queued(p))
++			continue;
++
++		printk("%s\tpid: %d, name: %s\n", loglvl, p->pid, p->comm);
++	}
++}
++
++int sched_cpu_dying(unsigned int cpu)
++{
++	struct rq *rq = cpu_rq(cpu);
++	unsigned long flags;
++
++	/* Handle pending wakeups and then migrate everything off */
++	sched_tick_stop(cpu);
++
++	raw_spin_lock_irqsave(&rq->lock, flags);
++	if (rq->nr_running != 1 || rq_has_pinned_tasks(rq)) {
++		WARN(true, "Dying CPU not properly vacated!");
++		dump_rq_tasks(rq, KERN_WARNING);
++	}
++	raw_spin_unlock_irqrestore(&rq->lock, flags);
++
++	calc_load_migrate(rq);
++	hrtick_clear(rq);
++	return 0;
++}
++#endif
++
++#ifdef CONFIG_SMP
++static void sched_init_topology_cpumask_early(void)
++{
++	int cpu;
++	cpumask_t *tmp;
++
++	for_each_possible_cpu(cpu) {
++		/* init topo masks */
++		tmp = per_cpu(sched_cpu_topo_masks, cpu);
++
++		cpumask_copy(tmp, cpumask_of(cpu));
++		tmp++;
++		cpumask_copy(tmp, cpu_possible_mask);
++		per_cpu(sched_cpu_llc_mask, cpu) = tmp;
++		per_cpu(sched_cpu_topo_end_mask, cpu) = ++tmp;
++		/*per_cpu(sd_llc_id, cpu) = cpu;*/
++	}
++}
++
++#define TOPOLOGY_CPUMASK(name, mask, last)\
++	if (cpumask_and(topo, topo, mask)) {					\
++		cpumask_copy(topo, mask);					\
++		printk(KERN_INFO "sched: cpu#%02d topo: 0x%08lx - "#name,	\
++		       cpu, (topo++)->bits[0]);					\
++	}									\
++	if (!last)								\
++		cpumask_complement(topo, mask)
++
++static void sched_init_topology_cpumask(void)
++{
++	int cpu;
++	cpumask_t *topo;
++
++	for_each_online_cpu(cpu) {
++		/* take chance to reset time slice for idle tasks */
++		cpu_rq(cpu)->idle->time_slice = sched_timeslice_ns;
++
++		topo = per_cpu(sched_cpu_topo_masks, cpu) + 1;
++
++		cpumask_complement(topo, cpumask_of(cpu));
++#ifdef CONFIG_SCHED_SMT
++		TOPOLOGY_CPUMASK(smt, topology_sibling_cpumask(cpu), false);
++#endif
++		per_cpu(sd_llc_id, cpu) = cpumask_first(cpu_coregroup_mask(cpu));
++		per_cpu(sched_cpu_llc_mask, cpu) = topo;
++		TOPOLOGY_CPUMASK(coregroup, cpu_coregroup_mask(cpu), false);
++
++		TOPOLOGY_CPUMASK(core, topology_core_cpumask(cpu), false);
++
++		TOPOLOGY_CPUMASK(others, cpu_online_mask, true);
++
++		per_cpu(sched_cpu_topo_end_mask, cpu) = topo;
++		printk(KERN_INFO "sched: cpu#%02d llc_id = %d, llc_mask idx = %d\n",
++		       cpu, per_cpu(sd_llc_id, cpu),
++		       (int) (per_cpu(sched_cpu_llc_mask, cpu) -
++			      per_cpu(sched_cpu_topo_masks, cpu)));
++	}
++}
++#endif
++
++void __init sched_init_smp(void)
++{
++	/* Move init over to a non-isolated CPU */
++	if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)
++		BUG();
++	current->flags &= ~PF_NO_SETAFFINITY;
++
++	sched_init_topology_cpumask();
++
++	sched_smp_initialized = true;
++}
++#else
++void __init sched_init_smp(void)
++{
++	cpu_rq(0)->idle->time_slice = sched_timeslice_ns;
++}
++#endif /* CONFIG_SMP */
++
++int in_sched_functions(unsigned long addr)
++{
++	return in_lock_functions(addr) ||
++		(addr >= (unsigned long)__sched_text_start
++		&& addr < (unsigned long)__sched_text_end);
++}
++
++#ifdef CONFIG_CGROUP_SCHED
++/* task group related information */
++struct task_group {
++	struct cgroup_subsys_state css;
++
++	struct rcu_head rcu;
++	struct list_head list;
++
++	struct task_group *parent;
++	struct list_head siblings;
++	struct list_head children;
++#ifdef CONFIG_FAIR_GROUP_SCHED
++	unsigned long		shares;
++#endif
++};
++
++/*
++ * Default task group.
++ * Every task in system belongs to this group at bootup.
++ */
++struct task_group root_task_group;
++LIST_HEAD(task_groups);
++
++/* Cacheline aligned slab cache for task_group */
++static struct kmem_cache *task_group_cache __read_mostly;
++#endif /* CONFIG_CGROUP_SCHED */
++
++void __init sched_init(void)
++{
++	int i;
++	struct rq *rq;
++
++	printk(KERN_INFO ALT_SCHED_VERSION_MSG);
++
++	wait_bit_init();
++
++#ifdef CONFIG_SMP
++	for (i = 0; i < SCHED_BITS; i++)
++		cpumask_copy(sched_rq_watermark + i, cpu_present_mask);
++#endif
++
++#ifdef CONFIG_CGROUP_SCHED
++	task_group_cache = KMEM_CACHE(task_group, 0);
++
++	list_add(&root_task_group.list, &task_groups);
++	INIT_LIST_HEAD(&root_task_group.children);
++	INIT_LIST_HEAD(&root_task_group.siblings);
++#endif /* CONFIG_CGROUP_SCHED */
++	for_each_possible_cpu(i) {
++		rq = cpu_rq(i);
++
++		sched_queue_init(&rq->queue);
++		rq->watermark = IDLE_TASK_SCHED_PRIO;
++		rq->skip = NULL;
++
++		raw_spin_lock_init(&rq->lock);
++		rq->nr_running = rq->nr_uninterruptible = 0;
++		rq->calc_load_active = 0;
++		rq->calc_load_update = jiffies + LOAD_FREQ;
++#ifdef CONFIG_SMP
++		rq->online = false;
++		rq->cpu = i;
++
++#ifdef CONFIG_SCHED_SMT
++		rq->active_balance = 0;
++#endif
++
++#ifdef CONFIG_NO_HZ_COMMON
++		INIT_CSD(&rq->nohz_csd, nohz_csd_func, rq);
++#endif
++		rq->balance_callback = &balance_push_callback;
++#ifdef CONFIG_HOTPLUG_CPU
++		rcuwait_init(&rq->hotplug_wait);
++#endif
++#endif /* CONFIG_SMP */
++		rq->nr_switches = 0;
++
++		hrtick_rq_init(rq);
++		atomic_set(&rq->nr_iowait, 0);
++	}
++#ifdef CONFIG_SMP
++	/* Set rq->online for cpu 0 */
++	cpu_rq(0)->online = true;
++#endif
++	/*
++	 * The boot idle thread does lazy MMU switching as well:
++	 */
++	mmgrab(&init_mm);
++	enter_lazy_tlb(&init_mm, current);
++
++	/*
++	 * Make us the idle thread. Technically, schedule() should not be
++	 * called from this thread, however somewhere below it might be,
++	 * but because we are the idle thread, we just pick up running again
++	 * when this runqueue becomes "idle".
++	 */
++	init_idle(current, smp_processor_id());
++
++	calc_load_update = jiffies + LOAD_FREQ;
++
++#ifdef CONFIG_SMP
++	idle_thread_set_boot_cpu();
++	balance_push_set(smp_processor_id(), false);
++
++	sched_init_topology_cpumask_early();
++#endif /* SMP */
++
++	psi_init();
++}
++
++#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
++static inline int preempt_count_equals(int preempt_offset)
++{
++	int nested = preempt_count() + rcu_preempt_depth();
++
++	return (nested == preempt_offset);
++}
++
++void __might_sleep(const char *file, int line, int preempt_offset)
++{
++	unsigned int state = get_current_state();
++	/*
++	 * Blocking primitives will set (and therefore destroy) current->state,
++	 * since we will exit with TASK_RUNNING make sure we enter with it,
++	 * otherwise we will destroy state.
++	 */
++	WARN_ONCE(state != TASK_RUNNING && current->task_state_change,
++			"do not call blocking ops when !TASK_RUNNING; "
++			"state=%x set at [<%p>] %pS\n", state,
++			(void *)current->task_state_change,
++			(void *)current->task_state_change);
++
++	___might_sleep(file, line, preempt_offset);
++}
++EXPORT_SYMBOL(__might_sleep);
++
++void ___might_sleep(const char *file, int line, int preempt_offset)
++{
++	/* Ratelimiting timestamp: */
++	static unsigned long prev_jiffy;
++
++	unsigned long preempt_disable_ip;
++
++	/* WARN_ON_ONCE() by default, no rate limit required: */
++	rcu_sleep_check();
++
++	if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
++	     !is_idle_task(current) && !current->non_block_count) ||
++	    system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING ||
++	    oops_in_progress)
++		return;
++	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
++		return;
++	prev_jiffy = jiffies;
++
++	/* Save this before calling printk(), since that will clobber it: */
++	preempt_disable_ip = get_preempt_disable_ip(current);
++
++	printk(KERN_ERR
++		"BUG: sleeping function called from invalid context at %s:%d\n",
++			file, line);
++	printk(KERN_ERR
++		"in_atomic(): %d, irqs_disabled(): %d, non_block: %d, pid: %d, name: %s\n",
++			in_atomic(), irqs_disabled(), current->non_block_count,
++			current->pid, current->comm);
++
++	if (task_stack_end_corrupted(current))
++		printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");
++
++	debug_show_held_locks(current);
++	if (irqs_disabled())
++		print_irqtrace_events(current);
++#ifdef CONFIG_DEBUG_PREEMPT
++	if (!preempt_count_equals(preempt_offset)) {
++		pr_err("Preemption disabled at:");
++		print_ip_sym(KERN_ERR, preempt_disable_ip);
++	}
++#endif
++	dump_stack();
++	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++}
++EXPORT_SYMBOL(___might_sleep);
++
++void __cant_sleep(const char *file, int line, int preempt_offset)
++{
++	static unsigned long prev_jiffy;
++
++	if (irqs_disabled())
++		return;
++
++	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
++		return;
++
++	if (preempt_count() > preempt_offset)
++		return;
++
++	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
++		return;
++	prev_jiffy = jiffies;
++
++	printk(KERN_ERR "BUG: assuming atomic context at %s:%d\n", file, line);
++	printk(KERN_ERR "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
++			in_atomic(), irqs_disabled(),
++			current->pid, current->comm);
++
++	debug_show_held_locks(current);
++	dump_stack();
++	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++}
++EXPORT_SYMBOL_GPL(__cant_sleep);
++
++#ifdef CONFIG_SMP
++void __cant_migrate(const char *file, int line)
++{
++	static unsigned long prev_jiffy;
++
++	if (irqs_disabled())
++		return;
++
++	if (is_migration_disabled(current))
++		return;
++
++	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
++		return;
++
++	if (preempt_count() > 0)
++		return;
++
++	if (current->migration_flags & MDF_FORCE_ENABLED)
++		return;
++
++	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
++		return;
++	prev_jiffy = jiffies;
++
++	pr_err("BUG: assuming non migratable context at %s:%d\n", file, line);
++	pr_err("in_atomic(): %d, irqs_disabled(): %d, migration_disabled() %u pid: %d, name: %s\n",
++	       in_atomic(), irqs_disabled(), is_migration_disabled(current),
++	       current->pid, current->comm);
++
++	debug_show_held_locks(current);
++	dump_stack();
++	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
++}
++EXPORT_SYMBOL_GPL(__cant_migrate);
++#endif
++#endif
++
++#ifdef CONFIG_MAGIC_SYSRQ
++void normalize_rt_tasks(void)
++{
++	struct task_struct *g, *p;
++	struct sched_attr attr = {
++		.sched_policy = SCHED_NORMAL,
++	};
++
++	read_lock(&tasklist_lock);
++	for_each_process_thread(g, p) {
++		/*
++		 * Only normalize user tasks:
++		 */
++		if (p->flags & PF_KTHREAD)
++			continue;
++
++		if (!rt_task(p)) {
++			/*
++			 * Renice negative nice level userspace
++			 * tasks back to 0:
++			 */
++			if (task_nice(p) < 0)
++				set_user_nice(p, 0);
++			continue;
++		}
++
++		__sched_setscheduler(p, &attr, false, false);
++	}
++	read_unlock(&tasklist_lock);
++}
++#endif /* CONFIG_MAGIC_SYSRQ */
++
++#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
++/*
++ * These functions are only useful for the IA64 MCA handling, or kdb.
++ *
++ * They can only be called when the whole system has been
++ * stopped - every CPU needs to be quiescent, and no scheduling
++ * activity can take place. Using them for anything else would
++ * be a serious bug, and as a result, they aren't even visible
++ * under any other configuration.
++ */
++
++/**
++ * curr_task - return the current task for a given CPU.
++ * @cpu: the processor in question.
++ *
++ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
++ *
++ * Return: The current task for @cpu.
++ */
++struct task_struct *curr_task(int cpu)
++{
++	return cpu_curr(cpu);
++}
++
++#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
++
++#ifdef CONFIG_IA64
++/**
++ * ia64_set_curr_task - set the current task for a given CPU.
++ * @cpu: the processor in question.
++ * @p: the task pointer to set.
++ *
++ * Description: This function must only be used when non-maskable interrupts
++ * are serviced on a separate stack.  It allows the architecture to switch the
++ * notion of the current task on a CPU in a non-blocking manner.  This function
++ * must be called with all CPU's synchronised, and interrupts disabled, the
++ * and caller must save the original value of the current task (see
++ * curr_task() above) and restore that value before reenabling interrupts and
++ * re-starting the system.
++ *
++ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
++ */
++void ia64_set_curr_task(int cpu, struct task_struct *p)
++{
++	cpu_curr(cpu) = p;
++}
++
++#endif
++
++#ifdef CONFIG_CGROUP_SCHED
++static void sched_free_group(struct task_group *tg)
++{
++	kmem_cache_free(task_group_cache, tg);
++}
++
++/* allocate runqueue etc for a new task group */
++struct task_group *sched_create_group(struct task_group *parent)
++{
++	struct task_group *tg;
++
++	tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
++	if (!tg)
++		return ERR_PTR(-ENOMEM);
++
++	return tg;
++}
++
++void sched_online_group(struct task_group *tg, struct task_group *parent)
++{
++}
++
++/* rcu callback to free various structures associated with a task group */
++static void sched_free_group_rcu(struct rcu_head *rhp)
++{
++	/* Now it should be safe to free those cfs_rqs */
++	sched_free_group(container_of(rhp, struct task_group, rcu));
++}
++
++void sched_destroy_group(struct task_group *tg)
++{
++	/* Wait for possible concurrent references to cfs_rqs complete */
++	call_rcu(&tg->rcu, sched_free_group_rcu);
++}
++
++void sched_offline_group(struct task_group *tg)
++{
++}
++
++static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
++{
++	return css ? container_of(css, struct task_group, css) : NULL;
++}
++
++static struct cgroup_subsys_state *
++cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
++{
++	struct task_group *parent = css_tg(parent_css);
++	struct task_group *tg;
++
++	if (!parent) {
++		/* This is early initialization for the top cgroup */
++		return &root_task_group.css;
++	}
++
++	tg = sched_create_group(parent);
++	if (IS_ERR(tg))
++		return ERR_PTR(-ENOMEM);
++	return &tg->css;
++}
++
++/* Expose task group only after completing cgroup initialization */
++static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)
++{
++	struct task_group *tg = css_tg(css);
++	struct task_group *parent = css_tg(css->parent);
++
++	if (parent)
++		sched_online_group(tg, parent);
++	return 0;
++}
++
++static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)
++{
++	struct task_group *tg = css_tg(css);
++
++	sched_offline_group(tg);
++}
++
++static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
++{
++	struct task_group *tg = css_tg(css);
++
++	/*
++	 * Relies on the RCU grace period between css_released() and this.
++	 */
++	sched_free_group(tg);
++}
++
++static void cpu_cgroup_fork(struct task_struct *task)
++{
++}
++
++static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
++{
++	return 0;
++}
++
++static void cpu_cgroup_attach(struct cgroup_taskset *tset)
++{
++}
++
++#ifdef CONFIG_FAIR_GROUP_SCHED
++static DEFINE_MUTEX(shares_mutex);
++
++int sched_group_set_shares(struct task_group *tg, unsigned long shares)
++{
++	/*
++	 * We can't change the weight of the root cgroup.
++	 */
++	if (&root_task_group == tg)
++		return -EINVAL;
++
++	shares = clamp(shares, scale_load(MIN_SHARES), scale_load(MAX_SHARES));
++
++	mutex_lock(&shares_mutex);
++	if (tg->shares == shares)
++		goto done;
++
++	tg->shares = shares;
++done:
++	mutex_unlock(&shares_mutex);
++	return 0;
++}
++
++static int cpu_shares_write_u64(struct cgroup_subsys_state *css,
++				struct cftype *cftype, u64 shareval)
++{
++	if (shareval > scale_load_down(ULONG_MAX))
++		shareval = MAX_SHARES;
++	return sched_group_set_shares(css_tg(css), scale_load(shareval));
++}
++
++static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css,
++			       struct cftype *cft)
++{
++	struct task_group *tg = css_tg(css);
++
++	return (u64) scale_load_down(tg->shares);
++}
++#endif
++
++static struct cftype cpu_legacy_files[] = {
++#ifdef CONFIG_FAIR_GROUP_SCHED
++	{
++		.name = "shares",
++		.read_u64 = cpu_shares_read_u64,
++		.write_u64 = cpu_shares_write_u64,
++	},
++#endif
++	{ }	/* Terminate */
++};
++
++
++static struct cftype cpu_files[] = {
++	{ }	/* terminate */
++};
++
++static int cpu_extra_stat_show(struct seq_file *sf,
++			       struct cgroup_subsys_state *css)
++{
++	return 0;
++}
++
++struct cgroup_subsys cpu_cgrp_subsys = {
++	.css_alloc	= cpu_cgroup_css_alloc,
++	.css_online	= cpu_cgroup_css_online,
++	.css_released	= cpu_cgroup_css_released,
++	.css_free	= cpu_cgroup_css_free,
++	.css_extra_stat_show = cpu_extra_stat_show,
++	.fork		= cpu_cgroup_fork,
++	.can_attach	= cpu_cgroup_can_attach,
++	.attach		= cpu_cgroup_attach,
++	.legacy_cftypes	= cpu_files,
++	.legacy_cftypes	= cpu_legacy_files,
++	.dfl_cftypes	= cpu_files,
++	.early_init	= true,
++	.threaded	= true,
++};
++#endif	/* CONFIG_CGROUP_SCHED */
++
++#undef CREATE_TRACE_POINTS
+diff --git a/kernel/sched/alt_debug.c b/kernel/sched/alt_debug.c
+new file mode 100644
+index 000000000000..1212a031700e
+--- /dev/null
++++ b/kernel/sched/alt_debug.c
+@@ -0,0 +1,31 @@
++/*
++ * kernel/sched/alt_debug.c
++ *
++ * Print the alt scheduler debugging details
++ *
++ * Author: Alfred Chen
++ * Date  : 2020
++ */
++#include "sched.h"
++
++/*
++ * This allows printing both to /proc/sched_debug and
++ * to the console
++ */
++#define SEQ_printf(m, x...)			\
++ do {						\
++	if (m)					\
++		seq_printf(m, x);		\
++	else					\
++		pr_cont(x);			\
++ } while (0)
++
++void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
++			  struct seq_file *m)
++{
++	SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr_ns(p, ns),
++						get_nr_threads(p));
++}
++
++void proc_sched_set_task(struct task_struct *p)
++{}
+diff --git a/kernel/sched/alt_sched.h b/kernel/sched/alt_sched.h
+new file mode 100644
+index 000000000000..289058a09bd5
+--- /dev/null
++++ b/kernel/sched/alt_sched.h
+@@ -0,0 +1,666 @@
++#ifndef ALT_SCHED_H
++#define ALT_SCHED_H
++
++#include <linux/sched.h>
++
++#include <linux/sched/clock.h>
++#include <linux/sched/cpufreq.h>
++#include <linux/sched/cputime.h>
++#include <linux/sched/debug.h>
++#include <linux/sched/init.h>
++#include <linux/sched/isolation.h>
++#include <linux/sched/loadavg.h>
++#include <linux/sched/mm.h>
++#include <linux/sched/nohz.h>
++#include <linux/sched/signal.h>
++#include <linux/sched/stat.h>
++#include <linux/sched/sysctl.h>
++#include <linux/sched/task.h>
++#include <linux/sched/topology.h>
++#include <linux/sched/wake_q.h>
++
++#include <uapi/linux/sched/types.h>
++
++#include <linux/cgroup.h>
++#include <linux/cpufreq.h>
++#include <linux/cpuidle.h>
++#include <linux/cpuset.h>
++#include <linux/ctype.h>
++#include <linux/debugfs.h>
++#include <linux/kthread.h>
++#include <linux/livepatch.h>
++#include <linux/membarrier.h>
++#include <linux/proc_fs.h>
++#include <linux/psi.h>
++#include <linux/slab.h>
++#include <linux/stop_machine.h>
++#include <linux/suspend.h>
++#include <linux/swait.h>
++#include <linux/syscalls.h>
++#include <linux/tsacct_kern.h>
++
++#include <asm/tlb.h>
++
++#ifdef CONFIG_PARAVIRT
++# include <asm/paravirt.h>
++#endif
++
++#include "cpupri.h"
++
++#include <trace/events/sched.h>
++
++#ifdef CONFIG_SCHED_BMQ
++/* bits:
++ * RT(0-99), (Low prio adj range, nice width, high prio adj range) / 2, cpu idle task */
++#define SCHED_BITS	(MAX_RT_PRIO + NICE_WIDTH / 2 + MAX_PRIORITY_ADJ + 1)
++#endif
++
++#ifdef CONFIG_SCHED_PDS
++/* bits: RT(0-99), reserved(100-127), NORMAL_PRIO_NUM, cpu idle task */
++#define SCHED_BITS	(MIN_NORMAL_PRIO + NORMAL_PRIO_NUM + 1)
++#endif /* CONFIG_SCHED_PDS */
++
++#define IDLE_TASK_SCHED_PRIO	(SCHED_BITS - 1)
++
++#ifdef CONFIG_SCHED_DEBUG
++# define SCHED_WARN_ON(x)	WARN_ONCE(x, #x)
++extern void resched_latency_warn(int cpu, u64 latency);
++#else
++# define SCHED_WARN_ON(x)	({ (void)(x), 0; })
++static inline void resched_latency_warn(int cpu, u64 latency) {}
++#endif
++
++/*
++ * Increase resolution of nice-level calculations for 64-bit architectures.
++ * The extra resolution improves shares distribution and load balancing of
++ * low-weight task groups (eg. nice +19 on an autogroup), deeper taskgroup
++ * hierarchies, especially on larger systems. This is not a user-visible change
++ * and does not change the user-interface for setting shares/weights.
++ *
++ * We increase resolution only if we have enough bits to allow this increased
++ * resolution (i.e. 64-bit). The costs for increasing resolution when 32-bit
++ * are pretty high and the returns do not justify the increased costs.
++ *
++ * Really only required when CONFIG_FAIR_GROUP_SCHED=y is also set, but to
++ * increase coverage and consistency always enable it on 64-bit platforms.
++ */
++#ifdef CONFIG_64BIT
++# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
++# define scale_load(w)		((w) << SCHED_FIXEDPOINT_SHIFT)
++# define scale_load_down(w) \
++({ \
++	unsigned long __w = (w); \
++	if (__w) \
++		__w = max(2UL, __w >> SCHED_FIXEDPOINT_SHIFT); \
++	__w; \
++})
++#else
++# define NICE_0_LOAD_SHIFT	(SCHED_FIXEDPOINT_SHIFT)
++# define scale_load(w)		(w)
++# define scale_load_down(w)	(w)
++#endif
++
++#ifdef CONFIG_FAIR_GROUP_SCHED
++#define ROOT_TASK_GROUP_LOAD	NICE_0_LOAD
++
++/*
++ * A weight of 0 or 1 can cause arithmetics problems.
++ * A weight of a cfs_rq is the sum of weights of which entities
++ * are queued on this cfs_rq, so a weight of a entity should not be
++ * too large, so as the shares value of a task group.
++ * (The default weight is 1024 - so there's no practical
++ *  limitation from this.)
++ */
++#define MIN_SHARES		(1UL <<  1)
++#define MAX_SHARES		(1UL << 18)
++#endif
++
++/* task_struct::on_rq states: */
++#define TASK_ON_RQ_QUEUED	1
++#define TASK_ON_RQ_MIGRATING	2
++
++static inline int task_on_rq_queued(struct task_struct *p)
++{
++	return p->on_rq == TASK_ON_RQ_QUEUED;
++}
++
++static inline int task_on_rq_migrating(struct task_struct *p)
++{
++	return READ_ONCE(p->on_rq) == TASK_ON_RQ_MIGRATING;
++}
++
++/*
++ * wake flags
++ */
++#define WF_SYNC		0x01		/* waker goes to sleep after wakeup */
++#define WF_FORK		0x02		/* child wakeup after fork */
++#define WF_MIGRATED	0x04		/* internal use, task got migrated */
++#define WF_ON_CPU	0x08		/* Wakee is on_rq */
++
++#define SCHED_QUEUE_BITS	(SCHED_BITS - 1)
++
++struct sched_queue {
++	DECLARE_BITMAP(bitmap, SCHED_QUEUE_BITS);
++	struct list_head heads[SCHED_BITS];
++};
++
++/*
++ * This is the main, per-CPU runqueue data structure.
++ * This data should only be modified by the local cpu.
++ */
++struct rq {
++	/* runqueue lock: */
++	raw_spinlock_t lock;
++
++	struct task_struct __rcu *curr;
++	struct task_struct *idle, *stop, *skip;
++	struct mm_struct *prev_mm;
++
++	struct sched_queue	queue;
++#ifdef CONFIG_SCHED_PDS
++	u64			time_edge;
++#endif
++	unsigned long watermark;
++
++	/* switch count */
++	u64 nr_switches;
++
++	atomic_t nr_iowait;
++
++#ifdef CONFIG_SCHED_DEBUG
++	u64 last_seen_need_resched_ns;
++	int ticks_without_resched;
++#endif
++
++#ifdef CONFIG_MEMBARRIER
++	int membarrier_state;
++#endif
++
++#ifdef CONFIG_SMP
++	int cpu;		/* cpu of this runqueue */
++	bool online;
++
++	unsigned int		ttwu_pending;
++	unsigned char		nohz_idle_balance;
++	unsigned char		idle_balance;
++
++#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
++	struct sched_avg	avg_irq;
++#endif
++
++#ifdef CONFIG_SCHED_SMT
++	int active_balance;
++	struct cpu_stop_work	active_balance_work;
++#endif
++	struct callback_head	*balance_callback;
++#ifdef CONFIG_HOTPLUG_CPU
++	struct rcuwait		hotplug_wait;
++#endif
++	unsigned int		nr_pinned;
++
++#endif /* CONFIG_SMP */
++#ifdef CONFIG_IRQ_TIME_ACCOUNTING
++	u64 prev_irq_time;
++#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
++#ifdef CONFIG_PARAVIRT
++	u64 prev_steal_time;
++#endif /* CONFIG_PARAVIRT */
++#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
++	u64 prev_steal_time_rq;
++#endif /* CONFIG_PARAVIRT_TIME_ACCOUNTING */
++
++	/* For genenal cpu load util */
++	s32 load_history;
++	u64 load_block;
++	u64 load_stamp;
++
++	/* calc_load related fields */
++	unsigned long calc_load_update;
++	long calc_load_active;
++
++	u64 clock, last_tick;
++	u64 last_ts_switch;
++	u64 clock_task;
++
++	unsigned int  nr_running;
++	unsigned long nr_uninterruptible;
++
++#ifdef CONFIG_SCHED_HRTICK
++#ifdef CONFIG_SMP
++	call_single_data_t hrtick_csd;
++#endif
++	struct hrtimer		hrtick_timer;
++	ktime_t			hrtick_time;
++#endif
++
++#ifdef CONFIG_SCHEDSTATS
++
++	/* latency stats */
++	struct sched_info rq_sched_info;
++	unsigned long long rq_cpu_time;
++	/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
++
++	/* sys_sched_yield() stats */
++	unsigned int yld_count;
++
++	/* schedule() stats */
++	unsigned int sched_switch;
++	unsigned int sched_count;
++	unsigned int sched_goidle;
++
++	/* try_to_wake_up() stats */
++	unsigned int ttwu_count;
++	unsigned int ttwu_local;
++#endif /* CONFIG_SCHEDSTATS */
++
++#ifdef CONFIG_CPU_IDLE
++	/* Must be inspected within a rcu lock section */
++	struct cpuidle_state *idle_state;
++#endif
++
++#ifdef CONFIG_NO_HZ_COMMON
++#ifdef CONFIG_SMP
++	call_single_data_t	nohz_csd;
++#endif
++	atomic_t		nohz_flags;
++#endif /* CONFIG_NO_HZ_COMMON */
++};
++
++extern unsigned long rq_load_util(struct rq *rq, unsigned long max);
++
++extern unsigned long calc_load_update;
++extern atomic_long_t calc_load_tasks;
++
++extern void calc_global_load_tick(struct rq *this_rq);
++extern long calc_load_fold_active(struct rq *this_rq, long adjust);
++
++DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
++#define cpu_rq(cpu)		(&per_cpu(runqueues, (cpu)))
++#define this_rq()		this_cpu_ptr(&runqueues)
++#define task_rq(p)		cpu_rq(task_cpu(p))
++#define cpu_curr(cpu)		(cpu_rq(cpu)->curr)
++#define raw_rq()		raw_cpu_ptr(&runqueues)
++
++#ifdef CONFIG_SMP
++#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
++void register_sched_domain_sysctl(void);
++void unregister_sched_domain_sysctl(void);
++#else
++static inline void register_sched_domain_sysctl(void)
++{
++}
++static inline void unregister_sched_domain_sysctl(void)
++{
++}
++#endif
++
++extern bool sched_smp_initialized;
++
++enum {
++	ITSELF_LEVEL_SPACE_HOLDER,
++#ifdef CONFIG_SCHED_SMT
++	SMT_LEVEL_SPACE_HOLDER,
++#endif
++	COREGROUP_LEVEL_SPACE_HOLDER,
++	CORE_LEVEL_SPACE_HOLDER,
++	OTHER_LEVEL_SPACE_HOLDER,
++	NR_CPU_AFFINITY_LEVELS
++};
++
++DECLARE_PER_CPU(cpumask_t [NR_CPU_AFFINITY_LEVELS], sched_cpu_topo_masks);
++DECLARE_PER_CPU(cpumask_t *, sched_cpu_llc_mask);
++
++static inline int
++__best_mask_cpu(const cpumask_t *cpumask, const cpumask_t *mask)
++{
++	int cpu;
++
++	while ((cpu = cpumask_any_and(cpumask, mask)) >= nr_cpu_ids)
++		mask++;
++
++	return cpu;
++}
++
++static inline int best_mask_cpu(int cpu, const cpumask_t *mask)
++{
++	return __best_mask_cpu(mask, per_cpu(sched_cpu_topo_masks, cpu));
++}
++
++extern void flush_smp_call_function_from_idle(void);
++
++#else  /* !CONFIG_SMP */
++static inline void flush_smp_call_function_from_idle(void) { }
++#endif
++
++#ifndef arch_scale_freq_tick
++static __always_inline
++void arch_scale_freq_tick(void)
++{
++}
++#endif
++
++#ifndef arch_scale_freq_capacity
++static __always_inline
++unsigned long arch_scale_freq_capacity(int cpu)
++{
++	return SCHED_CAPACITY_SCALE;
++}
++#endif
++
++static inline u64 __rq_clock_broken(struct rq *rq)
++{
++	return READ_ONCE(rq->clock);
++}
++
++static inline u64 rq_clock(struct rq *rq)
++{
++	/*
++	 * Relax lockdep_assert_held() checking as in VRQ, call to
++	 * sched_info_xxxx() may not held rq->lock
++	 * lockdep_assert_held(&rq->lock);
++	 */
++	return rq->clock;
++}
++
++static inline u64 rq_clock_task(struct rq *rq)
++{
++	/*
++	 * Relax lockdep_assert_held() checking as in VRQ, call to
++	 * sched_info_xxxx() may not held rq->lock
++	 * lockdep_assert_held(&rq->lock);
++	 */
++	return rq->clock_task;
++}
++
++/*
++ * {de,en}queue flags:
++ *
++ * DEQUEUE_SLEEP  - task is no longer runnable
++ * ENQUEUE_WAKEUP - task just became runnable
++ *
++ */
++
++#define DEQUEUE_SLEEP		0x01
++
++#define ENQUEUE_WAKEUP		0x01
++
++
++/*
++ * Below are scheduler API which using in other kernel code
++ * It use the dummy rq_flags
++ * ToDo : BMQ need to support these APIs for compatibility with mainline
++ * scheduler code.
++ */
++struct rq_flags {
++	unsigned long flags;
++};
++
++struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
++	__acquires(rq->lock);
++
++struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
++	__acquires(p->pi_lock)
++	__acquires(rq->lock);
++
++static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
++	__releases(rq->lock)
++{
++	raw_spin_unlock(&rq->lock);
++}
++
++static inline void
++task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
++	__releases(rq->lock)
++	__releases(p->pi_lock)
++{
++	raw_spin_unlock(&rq->lock);
++	raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
++}
++
++static inline void
++rq_lock(struct rq *rq, struct rq_flags *rf)
++	__acquires(rq->lock)
++{
++	raw_spin_lock(&rq->lock);
++}
++
++static inline void
++rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
++	__releases(rq->lock)
++{
++	raw_spin_unlock_irq(&rq->lock);
++}
++
++static inline void
++rq_unlock(struct rq *rq, struct rq_flags *rf)
++	__releases(rq->lock)
++{
++	raw_spin_unlock(&rq->lock);
++}
++
++static inline struct rq *
++this_rq_lock_irq(struct rq_flags *rf)
++	__acquires(rq->lock)
++{
++	struct rq *rq;
++
++	local_irq_disable();
++	rq = this_rq();
++	raw_spin_lock(&rq->lock);
++
++	return rq;
++}
++
++extern void raw_spin_rq_lock_nested(struct rq *rq, int subclass);
++extern void raw_spin_rq_unlock(struct rq *rq);
++
++static inline raw_spinlock_t *__rq_lockp(struct rq *rq)
++{
++	return &rq->lock;
++}
++
++static inline raw_spinlock_t *rq_lockp(struct rq *rq)
++{
++	return __rq_lockp(rq);
++}
++
++static inline void raw_spin_rq_lock(struct rq *rq)
++{
++	raw_spin_rq_lock_nested(rq, 0);
++}
++
++static inline void raw_spin_rq_lock_irq(struct rq *rq)
++{
++	local_irq_disable();
++	raw_spin_rq_lock(rq);
++}
++
++static inline void raw_spin_rq_unlock_irq(struct rq *rq)
++{
++	raw_spin_rq_unlock(rq);
++	local_irq_enable();
++}
++
++static inline int task_current(struct rq *rq, struct task_struct *p)
++{
++	return rq->curr == p;
++}
++
++static inline bool task_running(struct task_struct *p)
++{
++	return p->on_cpu;
++}
++
++extern int task_running_nice(struct task_struct *p);
++
++extern struct static_key_false sched_schedstats;
++
++#ifdef CONFIG_CPU_IDLE
++static inline void idle_set_state(struct rq *rq,
++				  struct cpuidle_state *idle_state)
++{
++	rq->idle_state = idle_state;
++}
++
++static inline struct cpuidle_state *idle_get_state(struct rq *rq)
++{
++	WARN_ON(!rcu_read_lock_held());
++	return rq->idle_state;
++}
++#else
++static inline void idle_set_state(struct rq *rq,
++				  struct cpuidle_state *idle_state)
++{
++}
++
++static inline struct cpuidle_state *idle_get_state(struct rq *rq)
++{
++	return NULL;
++}
++#endif
++
++static inline int cpu_of(const struct rq *rq)
++{
++#ifdef CONFIG_SMP
++	return rq->cpu;
++#else
++	return 0;
++#endif
++}
++
++#include "stats.h"
++
++#ifdef CONFIG_NO_HZ_COMMON
++#define NOHZ_BALANCE_KICK_BIT	0
++#define NOHZ_STATS_KICK_BIT	1
++
++#define NOHZ_BALANCE_KICK	BIT(NOHZ_BALANCE_KICK_BIT)
++#define NOHZ_STATS_KICK		BIT(NOHZ_STATS_KICK_BIT)
++
++#define NOHZ_KICK_MASK	(NOHZ_BALANCE_KICK | NOHZ_STATS_KICK)
++
++#define nohz_flags(cpu)	(&cpu_rq(cpu)->nohz_flags)
++
++/* TODO: needed?
++extern void nohz_balance_exit_idle(struct rq *rq);
++#else
++static inline void nohz_balance_exit_idle(struct rq *rq) { }
++*/
++#endif
++
++#ifdef CONFIG_IRQ_TIME_ACCOUNTING
++struct irqtime {
++	u64			total;
++	u64			tick_delta;
++	u64			irq_start_time;
++	struct u64_stats_sync	sync;
++};
++
++DECLARE_PER_CPU(struct irqtime, cpu_irqtime);
++
++/*
++ * Returns the irqtime minus the softirq time computed by ksoftirqd.
++ * Otherwise ksoftirqd's sum_exec_runtime is substracted its own runtime
++ * and never move forward.
++ */
++static inline u64 irq_time_read(int cpu)
++{
++	struct irqtime *irqtime = &per_cpu(cpu_irqtime, cpu);
++	unsigned int seq;
++	u64 total;
++
++	do {
++		seq = __u64_stats_fetch_begin(&irqtime->sync);
++		total = irqtime->total;
++	} while (__u64_stats_fetch_retry(&irqtime->sync, seq));
++
++	return total;
++}
++#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
++
++#ifdef CONFIG_CPU_FREQ
++DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
++#endif /* CONFIG_CPU_FREQ */
++
++#ifdef CONFIG_NO_HZ_FULL
++extern int __init sched_tick_offload_init(void);
++#else
++static inline int sched_tick_offload_init(void) { return 0; }
++#endif
++
++#ifdef arch_scale_freq_capacity
++#ifndef arch_scale_freq_invariant
++#define arch_scale_freq_invariant()	(true)
++#endif
++#else /* arch_scale_freq_capacity */
++#define arch_scale_freq_invariant()	(false)
++#endif
++
++extern void schedule_idle(void);
++
++#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
++
++/*
++ * !! For sched_setattr_nocheck() (kernel) only !!
++ *
++ * This is actually gross. :(
++ *
++ * It is used to make schedutil kworker(s) higher priority than SCHED_DEADLINE
++ * tasks, but still be able to sleep. We need this on platforms that cannot
++ * atomically change clock frequency. Remove once fast switching will be
++ * available on such platforms.
++ *
++ * SUGOV stands for SchedUtil GOVernor.
++ */
++#define SCHED_FLAG_SUGOV	0x10000000
++
++#ifdef CONFIG_MEMBARRIER
++/*
++ * The scheduler provides memory barriers required by membarrier between:
++ * - prior user-space memory accesses and store to rq->membarrier_state,
++ * - store to rq->membarrier_state and following user-space memory accesses.
++ * In the same way it provides those guarantees around store to rq->curr.
++ */
++static inline void membarrier_switch_mm(struct rq *rq,
++					struct mm_struct *prev_mm,
++					struct mm_struct *next_mm)
++{
++	int membarrier_state;
++
++	if (prev_mm == next_mm)
++		return;
++
++	membarrier_state = atomic_read(&next_mm->membarrier_state);
++	if (READ_ONCE(rq->membarrier_state) == membarrier_state)
++		return;
++
++	WRITE_ONCE(rq->membarrier_state, membarrier_state);
++}
++#else
++static inline void membarrier_switch_mm(struct rq *rq,
++					struct mm_struct *prev_mm,
++					struct mm_struct *next_mm)
++{
++}
++#endif
++
++#ifdef CONFIG_NUMA
++extern int sched_numa_find_closest(const struct cpumask *cpus, int cpu);
++#else
++static inline int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
++{
++	return nr_cpu_ids;
++}
++#endif
++
++extern void swake_up_all_locked(struct swait_queue_head *q);
++extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
++
++#ifdef CONFIG_PREEMPT_DYNAMIC
++extern int preempt_dynamic_mode;
++extern int sched_dynamic_mode(const char *str);
++extern void sched_dynamic_update(int mode);
++#endif
++
++static inline void nohz_run_idle_balance(int cpu) { }
++#endif /* ALT_SCHED_H */
+diff --git a/kernel/sched/bmq.h b/kernel/sched/bmq.h
+new file mode 100644
+index 000000000000..be3ee4a553ca
+--- /dev/null
++++ b/kernel/sched/bmq.h
+@@ -0,0 +1,111 @@
++#define ALT_SCHED_VERSION_MSG "sched/bmq: BMQ CPU Scheduler "ALT_SCHED_VERSION" by Alfred Chen.\n"
++
++/*
++ * BMQ only routines
++ */
++#define rq_switch_time(rq)	((rq)->clock - (rq)->last_ts_switch)
++#define boost_threshold(p)	(sched_timeslice_ns >>\
++				 (15 - MAX_PRIORITY_ADJ -  (p)->boost_prio))
++
++static inline void boost_task(struct task_struct *p)
++{
++	int limit;
++
++	switch (p->policy) {
++	case SCHED_NORMAL:
++		limit = -MAX_PRIORITY_ADJ;
++		break;
++	case SCHED_BATCH:
++	case SCHED_IDLE:
++		limit = 0;
++		break;
++	default:
++		return;
++	}
++
++	if (p->boost_prio > limit)
++		p->boost_prio--;
++}
++
++static inline void deboost_task(struct task_struct *p)
++{
++	if (p->boost_prio < MAX_PRIORITY_ADJ)
++		p->boost_prio++;
++}
++
++/*
++ * Common interfaces
++ */
++static inline void sched_timeslice_imp(const int timeslice_ms) {}
++
++static inline int
++task_sched_prio_normal(const struct task_struct *p, const struct rq *rq)
++{
++	return p->prio + p->boost_prio - MAX_RT_PRIO;
++}
++
++static inline int task_sched_prio(const struct task_struct *p)
++{
++	return (p->prio < MAX_RT_PRIO)? p->prio : MAX_RT_PRIO / 2 + (p->prio + p->boost_prio) / 2;
++}
++
++static inline int
++task_sched_prio_idx(const struct task_struct *p, const struct rq *rq)
++{
++	return task_sched_prio(p);
++}
++
++static inline int sched_prio2idx(int prio, struct rq *rq)
++{
++	return prio;
++}
++
++static inline int sched_idx2prio(int idx, struct rq *rq)
++{
++	return idx;
++}
++
++static inline void time_slice_expired(struct task_struct *p, struct rq *rq)
++{
++	p->time_slice = sched_timeslice_ns;
++
++	if (SCHED_FIFO != p->policy && task_on_rq_queued(p)) {
++		if (SCHED_RR != p->policy)
++			deboost_task(p);
++		requeue_task(p, rq);
++	}
++}
++
++static inline void sched_task_sanity_check(struct task_struct *p, struct rq *rq) {}
++
++inline int task_running_nice(struct task_struct *p)
++{
++	return (p->prio + p->boost_prio > DEFAULT_PRIO + MAX_PRIORITY_ADJ);
++}
++
++static void sched_task_fork(struct task_struct *p, struct rq *rq)
++{
++	p->boost_prio = (p->boost_prio < 0) ?
++		p->boost_prio + MAX_PRIORITY_ADJ : MAX_PRIORITY_ADJ;
++}
++
++static inline void do_sched_yield_type_1(struct task_struct *p, struct rq *rq)
++{
++	p->boost_prio = MAX_PRIORITY_ADJ;
++}
++
++#ifdef CONFIG_SMP
++static inline void sched_task_ttwu(struct task_struct *p)
++{
++	if(this_rq()->clock_task - p->last_ran > sched_timeslice_ns)
++		boost_task(p);
++}
++#endif
++
++static inline void sched_task_deactivate(struct task_struct *p, struct rq *rq)
++{
++	if (rq_switch_time(rq) < boost_threshold(p))
++		boost_task(p);
++}
++
++static inline void update_rq_time_edge(struct rq *rq) {}
+diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
+index e7af18857371..3e38816b736e 100644
+--- a/kernel/sched/cpufreq_schedutil.c
++++ b/kernel/sched/cpufreq_schedutil.c
+@@ -167,9 +167,14 @@ static void sugov_get_util(struct sugov_cpu *sg_cpu)
+ 	unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu);
+ 
+ 	sg_cpu->max = max;
++#ifndef CONFIG_SCHED_ALT
+ 	sg_cpu->bw_dl = cpu_bw_dl(rq);
+ 	sg_cpu->util = effective_cpu_util(sg_cpu->cpu, cpu_util_cfs(rq), max,
+ 					  FREQUENCY_UTIL, NULL);
++#else
++	sg_cpu->bw_dl = 0;
++	sg_cpu->util = rq_load_util(rq, max);
++#endif /* CONFIG_SCHED_ALT */
+ }
+ 
+ /**
+@@ -312,8 +317,10 @@ static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
+  */
+ static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu)
+ {
++#ifndef CONFIG_SCHED_ALT
+ 	if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
+ 		sg_cpu->sg_policy->limits_changed = true;
++#endif
+ }
+ 
+ static inline bool sugov_update_single_common(struct sugov_cpu *sg_cpu,
+@@ -607,6 +614,7 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy)
+ 	}
+ 
+ 	ret = sched_setattr_nocheck(thread, &attr);
++
+ 	if (ret) {
+ 		kthread_stop(thread);
+ 		pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
+@@ -839,7 +847,9 @@ cpufreq_governor_init(schedutil_gov);
+ #ifdef CONFIG_ENERGY_MODEL
+ static void rebuild_sd_workfn(struct work_struct *work)
+ {
++#ifndef CONFIG_SCHED_ALT
+ 	rebuild_sched_domains_energy();
++#endif /* CONFIG_SCHED_ALT */
+ }
+ static DECLARE_WORK(rebuild_sd_work, rebuild_sd_workfn);
+ 
+diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
+index 872e481d5098..f920c8b48ec1 100644
+--- a/kernel/sched/cputime.c
++++ b/kernel/sched/cputime.c
+@@ -123,7 +123,7 @@ void account_user_time(struct task_struct *p, u64 cputime)
+ 	p->utime += cputime;
+ 	account_group_user_time(p, cputime);
+ 
+-	index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
++	index = task_running_nice(p) ? CPUTIME_NICE : CPUTIME_USER;
+ 
+ 	/* Add user time to cpustat. */
+ 	task_group_account_field(p, index, cputime);
+@@ -147,7 +147,7 @@ void account_guest_time(struct task_struct *p, u64 cputime)
+ 	p->gtime += cputime;
+ 
+ 	/* Add guest time to cpustat. */
+-	if (task_nice(p) > 0) {
++	if (task_running_nice(p)) {
+ 		cpustat[CPUTIME_NICE] += cputime;
+ 		cpustat[CPUTIME_GUEST_NICE] += cputime;
+ 	} else {
+@@ -270,7 +270,7 @@ static inline u64 account_other_time(u64 max)
+ #ifdef CONFIG_64BIT
+ static inline u64 read_sum_exec_runtime(struct task_struct *t)
+ {
+-	return t->se.sum_exec_runtime;
++	return tsk_seruntime(t);
+ }
+ #else
+ static u64 read_sum_exec_runtime(struct task_struct *t)
+@@ -280,7 +280,7 @@ static u64 read_sum_exec_runtime(struct task_struct *t)
+ 	struct rq *rq;
+ 
+ 	rq = task_rq_lock(t, &rf);
+-	ns = t->se.sum_exec_runtime;
++	ns = tsk_seruntime(t);
+ 	task_rq_unlock(rq, t, &rf);
+ 
+ 	return ns;
+@@ -612,7 +612,7 @@ void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
+ void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
+ {
+ 	struct task_cputime cputime = {
+-		.sum_exec_runtime = p->se.sum_exec_runtime,
++		.sum_exec_runtime = tsk_seruntime(p),
+ 	};
+ 
+ 	task_cputime(p, &cputime.utime, &cputime.stime);
+diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
+index 17a653b67006..17ab2fe34d7a 100644
+--- a/kernel/sched/debug.c
++++ b/kernel/sched/debug.c
+@@ -8,6 +8,7 @@
+  */
+ #include "sched.h"
+ 
++#ifndef CONFIG_SCHED_ALT
+ /*
+  * This allows printing both to /proc/sched_debug and
+  * to the console
+@@ -216,6 +217,7 @@ static const struct file_operations sched_scaling_fops = {
+ };
+ 
+ #endif /* SMP */
++#endif /* !CONFIG_SCHED_ALT */
+ 
+ #ifdef CONFIG_PREEMPT_DYNAMIC
+ 
+@@ -279,6 +281,7 @@ static const struct file_operations sched_dynamic_fops = {
+ 
+ #endif /* CONFIG_PREEMPT_DYNAMIC */
+ 
++#ifndef CONFIG_SCHED_ALT
+ __read_mostly bool sched_debug_verbose;
+ 
+ static const struct seq_operations sched_debug_sops;
+@@ -294,6 +297,7 @@ static const struct file_operations sched_debug_fops = {
+ 	.llseek		= seq_lseek,
+ 	.release	= seq_release,
+ };
++#endif /* !CONFIG_SCHED_ALT */
+ 
+ static struct dentry *debugfs_sched;
+ 
+@@ -303,12 +307,15 @@ static __init int sched_init_debug(void)
+ 
+ 	debugfs_sched = debugfs_create_dir("sched", NULL);
+ 
++#ifndef CONFIG_SCHED_ALT
+ 	debugfs_create_file("features", 0644, debugfs_sched, NULL, &sched_feat_fops);
+ 	debugfs_create_bool("verbose", 0644, debugfs_sched, &sched_debug_verbose);
++#endif /* !CONFIG_SCHED_ALT */
+ #ifdef CONFIG_PREEMPT_DYNAMIC
+ 	debugfs_create_file("preempt", 0644, debugfs_sched, NULL, &sched_dynamic_fops);
+ #endif
+ 
++#ifndef CONFIG_SCHED_ALT
+ 	debugfs_create_u32("latency_ns", 0644, debugfs_sched, &sysctl_sched_latency);
+ 	debugfs_create_u32("min_granularity_ns", 0644, debugfs_sched, &sysctl_sched_min_granularity);
+ 	debugfs_create_u32("wakeup_granularity_ns", 0644, debugfs_sched, &sysctl_sched_wakeup_granularity);
+@@ -336,11 +343,13 @@ static __init int sched_init_debug(void)
+ #endif
+ 
+ 	debugfs_create_file("debug", 0444, debugfs_sched, NULL, &sched_debug_fops);
++#endif /* !CONFIG_SCHED_ALT */
+ 
+ 	return 0;
+ }
+ late_initcall(sched_init_debug);
+ 
++#ifndef CONFIG_SCHED_ALT
+ #ifdef CONFIG_SMP
+ 
+ static cpumask_var_t		sd_sysctl_cpus;
+@@ -1063,6 +1072,7 @@ void proc_sched_set_task(struct task_struct *p)
+ 	memset(&p->se.statistics, 0, sizeof(p->se.statistics));
+ #endif
+ }
++#endif /* !CONFIG_SCHED_ALT */
+ 
+ void resched_latency_warn(int cpu, u64 latency)
+ {
+diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
+index d17b0a5ce6ac..6ff77fc6b73a 100644
+--- a/kernel/sched/idle.c
++++ b/kernel/sched/idle.c
+@@ -403,6 +403,7 @@ void cpu_startup_entry(enum cpuhp_state state)
+ 		do_idle();
+ }
+ 
++#ifndef CONFIG_SCHED_ALT
+ /*
+  * idle-task scheduling class.
+  */
+@@ -525,3 +526,4 @@ DEFINE_SCHED_CLASS(idle) = {
+ 	.switched_to		= switched_to_idle,
+ 	.update_curr		= update_curr_idle,
+ };
++#endif
+diff --git a/kernel/sched/pds.h b/kernel/sched/pds.h
+new file mode 100644
+index 000000000000..0f1f0d708b77
+--- /dev/null
++++ b/kernel/sched/pds.h
+@@ -0,0 +1,127 @@
++#define ALT_SCHED_VERSION_MSG "sched/pds: PDS CPU Scheduler "ALT_SCHED_VERSION" by Alfred Chen.\n"
++
++static int sched_timeslice_shift = 22;
++
++#define NORMAL_PRIO_MOD(x)	((x) & (NORMAL_PRIO_NUM - 1))
++
++/*
++ * Common interfaces
++ */
++static inline void sched_timeslice_imp(const int timeslice_ms)
++{
++	if (2 == timeslice_ms)
++		sched_timeslice_shift = 21;
++}
++
++static inline int
++task_sched_prio_normal(const struct task_struct *p, const struct rq *rq)
++{
++	s64 delta = p->deadline - rq->time_edge + NORMAL_PRIO_NUM - NICE_WIDTH;
++
++	if (WARN_ONCE(delta > NORMAL_PRIO_NUM - 1,
++		      "pds: task_sched_prio_normal() delta %lld\n", delta))
++		return NORMAL_PRIO_NUM - 1;
++
++	return (delta < 0) ? 0 : delta;
++}
++
++static inline int task_sched_prio(const struct task_struct *p)
++{
++	return (p->prio < MAX_RT_PRIO) ? p->prio :
++		MIN_NORMAL_PRIO + task_sched_prio_normal(p, task_rq(p));
++}
++
++static inline int
++task_sched_prio_idx(const struct task_struct *p, const struct rq *rq)
++{
++	return (p->prio < MAX_RT_PRIO) ? p->prio : MIN_NORMAL_PRIO +
++		NORMAL_PRIO_MOD(task_sched_prio_normal(p, rq) + rq->time_edge);
++}
++
++static inline int sched_prio2idx(int prio, struct rq *rq)
++{
++	return (IDLE_TASK_SCHED_PRIO == prio || prio < MAX_RT_PRIO) ? prio :
++		MIN_NORMAL_PRIO + NORMAL_PRIO_MOD((prio - MIN_NORMAL_PRIO) +
++						  rq->time_edge);
++}
++
++static inline int sched_idx2prio(int idx, struct rq *rq)
++{
++	return (idx < MAX_RT_PRIO) ? idx : MIN_NORMAL_PRIO +
++		NORMAL_PRIO_MOD((idx - MIN_NORMAL_PRIO) + NORMAL_PRIO_NUM -
++				NORMAL_PRIO_MOD(rq->time_edge));
++}
++
++static inline void sched_renew_deadline(struct task_struct *p, const struct rq *rq)
++{
++	if (p->prio >= MAX_RT_PRIO)
++		p->deadline = (rq->clock >> sched_timeslice_shift) +
++			p->static_prio - (MAX_PRIO - NICE_WIDTH);
++}
++
++int task_running_nice(struct task_struct *p)
++{
++	return (p->prio > DEFAULT_PRIO);
++}
++
++static inline void update_rq_time_edge(struct rq *rq)
++{
++	struct list_head head;
++	u64 old = rq->time_edge;
++	u64 now = rq->clock >> sched_timeslice_shift;
++	u64 prio, delta;
++
++	if (now == old)
++		return;
++
++	delta = min_t(u64, NORMAL_PRIO_NUM, now - old);
++	INIT_LIST_HEAD(&head);
++
++	for_each_set_bit(prio, &rq->queue.bitmap[2], delta)
++		list_splice_tail_init(rq->queue.heads + MIN_NORMAL_PRIO +
++				      NORMAL_PRIO_MOD(prio + old), &head);
++
++	rq->queue.bitmap[2] = (NORMAL_PRIO_NUM == delta) ? 0UL :
++		rq->queue.bitmap[2] >> delta;
++	rq->time_edge = now;
++	if (!list_empty(&head)) {
++		u64 idx = MIN_NORMAL_PRIO + NORMAL_PRIO_MOD(now);
++		struct task_struct *p;
++
++		list_for_each_entry(p, &head, sq_node)
++			p->sq_idx = idx;
++
++		list_splice(&head, rq->queue.heads + idx);
++		rq->queue.bitmap[2] |= 1UL;
++	}
++}
++
++static inline void time_slice_expired(struct task_struct *p, struct rq *rq)
++{
++	p->time_slice = sched_timeslice_ns;
++	sched_renew_deadline(p, rq);
++	if (SCHED_FIFO != p->policy && task_on_rq_queued(p))
++		requeue_task(p, rq);
++}
++
++static inline void sched_task_sanity_check(struct task_struct *p, struct rq *rq)
++{
++	u64 max_dl = rq->time_edge + NICE_WIDTH - 1;
++	if (unlikely(p->deadline > max_dl))
++		p->deadline = max_dl;
++}
++
++static void sched_task_fork(struct task_struct *p, struct rq *rq)
++{
++	sched_renew_deadline(p, rq);
++}
++
++static inline void do_sched_yield_type_1(struct task_struct *p, struct rq *rq)
++{
++	time_slice_expired(p, rq);
++}
++
++#ifdef CONFIG_SMP
++static inline void sched_task_ttwu(struct task_struct *p) {}
++#endif
++static inline void sched_task_deactivate(struct task_struct *p, struct rq *rq) {}
+diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
+index a554e3bbab2b..3e56f5e6ff5c 100644
+--- a/kernel/sched/pelt.c
++++ b/kernel/sched/pelt.c
+@@ -270,6 +270,7 @@ ___update_load_avg(struct sched_avg *sa, unsigned long load)
+ 	WRITE_ONCE(sa->util_avg, sa->util_sum / divider);
+ }
+ 
++#ifndef CONFIG_SCHED_ALT
+ /*
+  * sched_entity:
+  *
+@@ -387,8 +388,9 @@ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
+ 
+ 	return 0;
+ }
++#endif
+ 
+-#ifdef CONFIG_SCHED_THERMAL_PRESSURE
++#if defined(CONFIG_SCHED_THERMAL_PRESSURE) && !defined(CONFIG_SCHED_ALT)
+ /*
+  * thermal:
+  *
+diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h
+index e06071bf3472..adf567df34d4 100644
+--- a/kernel/sched/pelt.h
++++ b/kernel/sched/pelt.h
+@@ -1,13 +1,15 @@
+ #ifdef CONFIG_SMP
+ #include "sched-pelt.h"
+ 
++#ifndef CONFIG_SCHED_ALT
+ int __update_load_avg_blocked_se(u64 now, struct sched_entity *se);
+ int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se);
+ int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
+ int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
+ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
++#endif
+ 
+-#ifdef CONFIG_SCHED_THERMAL_PRESSURE
++#if defined(CONFIG_SCHED_THERMAL_PRESSURE) && !defined(CONFIG_SCHED_ALT)
+ int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity);
+ 
+ static inline u64 thermal_load_avg(struct rq *rq)
+@@ -42,6 +44,7 @@ static inline u32 get_pelt_divider(struct sched_avg *avg)
+ 	return LOAD_AVG_MAX - 1024 + avg->period_contrib;
+ }
+ 
++#ifndef CONFIG_SCHED_ALT
+ static inline void cfs_se_util_change(struct sched_avg *avg)
+ {
+ 	unsigned int enqueued;
+@@ -153,9 +156,11 @@ static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
+ 	return rq_clock_pelt(rq_of(cfs_rq));
+ }
+ #endif
++#endif /* CONFIG_SCHED_ALT */
+ 
+ #else
+ 
++#ifndef CONFIG_SCHED_ALT
+ static inline int
+ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
+ {
+@@ -173,6 +178,7 @@ update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
+ {
+ 	return 0;
+ }
++#endif
+ 
+ static inline int
+ update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
+index 3d3e5793e117..c1d976ef623f 100644
+--- a/kernel/sched/sched.h
++++ b/kernel/sched/sched.h
+@@ -2,6 +2,10 @@
+ /*
+  * Scheduler internal types and methods:
+  */
++#ifdef CONFIG_SCHED_ALT
++#include "alt_sched.h"
++#else
++
+ #include <linux/sched.h>
+ 
+ #include <linux/sched/autogroup.h>
+@@ -3064,3 +3068,8 @@ extern int sched_dynamic_mode(const char *str);
+ extern void sched_dynamic_update(int mode);
+ #endif
+ 
++static inline int task_running_nice(struct task_struct *p)
++{
++	return (task_nice(p) > 0);
++}
++#endif /* !CONFIG_SCHED_ALT */
+diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
+index 3f93fc3b5648..528b71e144e9 100644
+--- a/kernel/sched/stats.c
++++ b/kernel/sched/stats.c
+@@ -22,8 +22,10 @@ static int show_schedstat(struct seq_file *seq, void *v)
+ 	} else {
+ 		struct rq *rq;
+ #ifdef CONFIG_SMP
++#ifndef CONFIG_SCHED_ALT
+ 		struct sched_domain *sd;
+ 		int dcount = 0;
++#endif
+ #endif
+ 		cpu = (unsigned long)(v - 2);
+ 		rq = cpu_rq(cpu);
+@@ -40,6 +42,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
+ 		seq_printf(seq, "\n");
+ 
+ #ifdef CONFIG_SMP
++#ifndef CONFIG_SCHED_ALT
+ 		/* domain-specific stats */
+ 		rcu_read_lock();
+ 		for_each_domain(cpu, sd) {
+@@ -68,6 +71,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
+ 			    sd->ttwu_move_balance);
+ 		}
+ 		rcu_read_unlock();
++#endif
+ #endif
+ 	}
+ 	return 0;
+diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
+index 4e8698e62f07..36c61551252e 100644
+--- a/kernel/sched/topology.c
++++ b/kernel/sched/topology.c
+@@ -4,6 +4,7 @@
+  */
+ #include "sched.h"
+ 
++#ifndef CONFIG_SCHED_ALT
+ DEFINE_MUTEX(sched_domains_mutex);
+ 
+ /* Protected by sched_domains_mutex: */
+@@ -1382,8 +1383,10 @@ static void asym_cpu_capacity_scan(void)
+  */
+ 
+ static int default_relax_domain_level = -1;
++#endif /* CONFIG_SCHED_ALT */
+ int sched_domain_level_max;
+ 
++#ifndef CONFIG_SCHED_ALT
+ static int __init setup_relax_domain_level(char *str)
+ {
+ 	if (kstrtoint(str, 0, &default_relax_domain_level))
+@@ -1619,6 +1622,7 @@ sd_init(struct sched_domain_topology_level *tl,
+ 
+ 	return sd;
+ }
++#endif /* CONFIG_SCHED_ALT */
+ 
+ /*
+  * Topology list, bottom-up.
+@@ -1648,6 +1652,7 @@ void set_sched_topology(struct sched_domain_topology_level *tl)
+ 	sched_domain_topology = tl;
+ }
+ 
++#ifndef CONFIG_SCHED_ALT
+ #ifdef CONFIG_NUMA
+ 
+ static const struct cpumask *sd_numa_mask(int cpu)
+@@ -2516,3 +2521,17 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+ 	partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
+ 	mutex_unlock(&sched_domains_mutex);
+ }
++#else /* CONFIG_SCHED_ALT */
++void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
++			     struct sched_domain_attr *dattr_new)
++{}
++
++#ifdef CONFIG_NUMA
++int __read_mostly		node_reclaim_distance = RECLAIM_DISTANCE;
++
++int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
++{
++	return best_mask_cpu(cpu, cpus);
++}
++#endif /* CONFIG_NUMA */
++#endif
+diff --git a/kernel/sysctl.c b/kernel/sysctl.c
+index 083be6af29d7..09fc6281d488 100644
+--- a/kernel/sysctl.c
++++ b/kernel/sysctl.c
+@@ -122,6 +122,10 @@ static unsigned long long_max = LONG_MAX;
+ static int one_hundred = 100;
+ static int two_hundred = 200;
+ static int one_thousand = 1000;
++#ifdef CONFIG_SCHED_ALT
++static int __maybe_unused zero = 0;
++extern int sched_yield_type;
++#endif
+ #ifdef CONFIG_PRINTK
+ static int ten_thousand = 10000;
+ #endif
+@@ -1771,6 +1775,24 @@ int proc_do_static_key(struct ctl_table *table, int write,
+ }
+ 
+ static struct ctl_table kern_table[] = {
++#ifdef CONFIG_SCHED_ALT
++/* In ALT, only supported "sched_schedstats" */
++#ifdef CONFIG_SCHED_DEBUG
++#ifdef CONFIG_SMP
++#ifdef CONFIG_SCHEDSTATS
++	{
++		.procname	= "sched_schedstats",
++		.data		= NULL,
++		.maxlen		= sizeof(unsigned int),
++		.mode		= 0644,
++		.proc_handler	= sysctl_schedstats,
++		.extra1		= SYSCTL_ZERO,
++		.extra2		= SYSCTL_ONE,
++	},
++#endif /* CONFIG_SCHEDSTATS */
++#endif /* CONFIG_SMP */
++#endif /* CONFIG_SCHED_DEBUG */
++#else  /* !CONFIG_SCHED_ALT */
+ 	{
+ 		.procname	= "sched_child_runs_first",
+ 		.data		= &sysctl_sched_child_runs_first,
+@@ -1901,6 +1923,7 @@ static struct ctl_table kern_table[] = {
+ 		.extra2		= SYSCTL_ONE,
+ 	},
+ #endif
++#endif /* !CONFIG_SCHED_ALT */
+ #ifdef CONFIG_PROVE_LOCKING
+ 	{
+ 		.procname	= "prove_locking",
+@@ -2477,6 +2500,17 @@ static struct ctl_table kern_table[] = {
+ 		.proc_handler	= proc_dointvec,
+ 	},
+ #endif
++#ifdef CONFIG_SCHED_ALT
++	{
++		.procname	= "yield_type",
++		.data		= &sched_yield_type,
++		.maxlen		= sizeof (int),
++		.mode		= 0644,
++		.proc_handler	= &proc_dointvec_minmax,
++		.extra1		= &zero,
++		.extra2		= &two,
++	},
++#endif
+ #if defined(CONFIG_S390) && defined(CONFIG_SMP)
+ 	{
+ 		.procname	= "spin_retry",
+diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
+index 0ea8702eb516..a27a0f3a654d 100644
+--- a/kernel/time/hrtimer.c
++++ b/kernel/time/hrtimer.c
+@@ -2088,8 +2088,10 @@ long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
+ 	int ret = 0;
+ 	u64 slack;
+ 
++#ifndef CONFIG_SCHED_ALT
+ 	slack = current->timer_slack_ns;
+ 	if (dl_task(current) || rt_task(current))
++#endif
+ 		slack = 0;
+ 
+ 	hrtimer_init_sleeper_on_stack(&t, clockid, mode);
+diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
+index 643d412ac623..6bf27565242f 100644
+--- a/kernel/time/posix-cpu-timers.c
++++ b/kernel/time/posix-cpu-timers.c
+@@ -216,7 +216,7 @@ static void task_sample_cputime(struct task_struct *p, u64 *samples)
+ 	u64 stime, utime;
+ 
+ 	task_cputime(p, &utime, &stime);
+-	store_samples(samples, stime, utime, p->se.sum_exec_runtime);
++	store_samples(samples, stime, utime, tsk_seruntime(p));
+ }
+ 
+ static void proc_sample_cputime_atomic(struct task_cputime_atomic *at,
+@@ -859,6 +859,7 @@ static void collect_posix_cputimers(struct posix_cputimers *pct, u64 *samples,
+ 	}
+ }
+ 
++#ifndef CONFIG_SCHED_ALT
+ static inline void check_dl_overrun(struct task_struct *tsk)
+ {
+ 	if (tsk->dl.dl_overrun) {
+@@ -866,6 +867,7 @@ static inline void check_dl_overrun(struct task_struct *tsk)
+ 		__group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
+ 	}
+ }
++#endif
+ 
+ static bool check_rlimit(u64 time, u64 limit, int signo, bool rt, bool hard)
+ {
+@@ -893,8 +895,10 @@ static void check_thread_timers(struct task_struct *tsk,
+ 	u64 samples[CPUCLOCK_MAX];
+ 	unsigned long soft;
+ 
++#ifndef CONFIG_SCHED_ALT
+ 	if (dl_task(tsk))
+ 		check_dl_overrun(tsk);
++#endif
+ 
+ 	if (expiry_cache_is_inactive(pct))
+ 		return;
+@@ -908,7 +912,7 @@ static void check_thread_timers(struct task_struct *tsk,
+ 	soft = task_rlimit(tsk, RLIMIT_RTTIME);
+ 	if (soft != RLIM_INFINITY) {
+ 		/* Task RT timeout is accounted in jiffies. RTTIME is usec */
+-		unsigned long rttime = tsk->rt.timeout * (USEC_PER_SEC / HZ);
++		unsigned long rttime = tsk_rttimeout(tsk) * (USEC_PER_SEC / HZ);
+ 		unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
+ 
+ 		/* At the hard limit, send SIGKILL. No further action. */
+@@ -1144,8 +1148,10 @@ static inline bool fastpath_timer_check(struct task_struct *tsk)
+ 			return true;
+ 	}
+ 
++#ifndef CONFIG_SCHED_ALT
+ 	if (dl_task(tsk) && tsk->dl.dl_overrun)
+ 		return true;
++#endif
+ 
+ 	return false;
+ }
+diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
+index adf7ef194005..11c8f36e281b 100644
+--- a/kernel/trace/trace_selftest.c
++++ b/kernel/trace/trace_selftest.c
+@@ -1052,10 +1052,15 @@ static int trace_wakeup_test_thread(void *data)
+ {
+ 	/* Make this a -deadline thread */
+ 	static const struct sched_attr attr = {
++#ifdef CONFIG_SCHED_ALT
++		/* No deadline on BMQ/PDS, use RR */
++		.sched_policy = SCHED_RR,
++#else
+ 		.sched_policy = SCHED_DEADLINE,
+ 		.sched_runtime = 100000ULL,
+ 		.sched_deadline = 10000000ULL,
+ 		.sched_period = 10000000ULL
++#endif
+ 	};
+ 	struct wakeup_test_data *x = data;
+ 

diff --git a/5021_BMQ-and-PDS-gentoo-defaults.patch b/5021_BMQ-and-PDS-gentoo-defaults.patch
new file mode 100644
index 0000000..d449eec
--- /dev/null
+++ b/5021_BMQ-and-PDS-gentoo-defaults.patch
@@ -0,0 +1,13 @@
+--- a/init/Kconfig	2021-04-27 07:38:30.556467045 -0400
++++ b/init/Kconfig	2021-04-27 07:39:32.956412800 -0400
+@@ -780,8 +780,9 @@ config GENERIC_SCHED_CLOCK
+ menu "Scheduler features"
+ 
+ menuconfig SCHED_ALT
++	depends on X86_64
+ 	bool "Alternative CPU Schedulers"
+-	default y
++	default n
+ 	help
+ 	  This feature enable alternative CPU scheduler"
+