Re: [gentoo-dev] Adding USE=udev to linux profiles

[Ben Kohler]

On 07/26/2018 02:59 AM, Andrew Savchenko wrote:
> Hi!
>
> On Thu, 19 Jul 2018 16:51:17 -0500 Ben Kohler wrote:
>> I'd like to propose adding USE=udev to our linux profiles (in
>> profiles/default/linux/make.defaults probably).  This flag is already
>> enabled on desktop profiles but it also affects quite a few packages
>> used on non-desktop linux systems.
>>
>> This flag provides useful functionality that most linux users will want.
>>    I'm a bit surprised that we still don't have it in all linux profiles,
>> but I think we've worked around this in the past by adding IUSE=+udev to
>> quite a few of those packages (33 packages, 116 ebuilds, by my count).
>>
>> This missing flag came to my attention again on bug 661584 where lvm2
>> has IUSE=+udev but cryptsetup has only IUSE=udev, so non-desktop users
>> have a bit of a mismatch between the 2 and get ugly errors on cryptsetup.
>>
>> Since this flag only affects linux, I think it makes more sense to set
>> it in linux profiles than to use IUSE defaults.
>>
>> Any objections to this idea?
>
> A user had contacted me with his input from the HPC world, I'm
> redirecting his e-mail here. James is whitelisted now so he can
> further participate in this discussion himself if necessary.
>
> As an HPC user of Gentoo I agree that minimal and highly optimized
> Gentoo setups are indeed very useful and must stay that way.
>
> Begin forwarded message:
>
> Date: Wed, 25 Jul 2018 13:31:59 -0400
> From: james <garftd@×××××××.net>
> To: bircoph@g.o
> Subject: udev's future
>
>
> Hello Andrew,
>
>
> Sorry, I do not have direct posting ability to gentoo-dev, so in
> hopes of finding a dev-sponsor, I hope you will paraphrase this
> email to you for the sake of preventing 'dev as a default' or base
> setting of any sort.
>
>
> My research and testing for  new HPC configurations, has systemd
> and udev at the heart of codes to avoid to optimize the
> heterogeneous nature of the clusters I'm building. In fact my
> development work, although delayed due to transient-illness, is
> more of a gentoo-centric convergence of embedded-gentoo, minimal
> (server) gentoo, gentoo-hpc clusters and unikernels. As far as
> performance and security are concerned  'less' is always better.
> Those codes and ebuild that are desired are to added in a higher
> level; hoping to continue the leverage the portage tree of
> applications, only as dynamically required.
>
>
> Avoidance of setting udev or in any form mandating any part of
> systemd will have dire consequences and cost me months, if not
> years  to find a way to 'totally undo' the ravages of udev.
> Minimized kernels are also fundamental to my loosely-coupled
> (gentoo) HPC development. Even tiny Rtos based embedded linux
> systems are in the process of being included in a loosely-coupled
> gentoo centric heterogeneous HPC cluster.  I would 'beg' against
> making udev primary under any circumstance.
>
>
> Gentoo has a unique and powerful position, just for it's position of
> choice and minimizational features; After 15 years, I'd hate to have
> to work in another distro, as gentoo has served me extraordinarily
> well over the decades.
>
>
> sincerely,
> James Horton, PE
>
> Best regards,
> Andrew Savchenko
>
No one was ever talking about forcing udev usage, just default-enabling 
support on a few MORE packages than we already do.  Our standard linux 
stage3's are already udev-enabled.  But not udev-forced, anywhere.

Nothing about my proposal was going to force udev on people who don't 
want udev at all-- let's not even go down that rabbit hole of discussion.

I was only pushing for more consistency-- either your system would be 
fully udev-enabled, or not at all.

-Ben