Gentoo Archives: gentoo-dev

From: Greg KH <gregkh@g.o>
To: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] devfs is dead, let's move on
Date: Thu, 07 Jul 2005 21:01:24
Message-Id: 20050707205236.GB30988@kroah.com
In Reply to: Re: [gentoo-dev] devfs is dead, let's move on by Martin Schlemmer
1 On Thu, Jul 07, 2005 at 03:55:45PM +0200, Martin Schlemmer wrote:
2 > On Wed, 2005-07-06 at 15:46 -0700, Greg KH wrote:
3 > > Ok, now that devfs is removed from the 2.6 kernel tree[1], I think it's
4 > > time to start to revisit some of the /dev naming rules that we currently
5 > > are living with[2].
6 > >
7 > > To start with, the 061 version of udev offers a big memory savings if
8 > > you use the "default" kernel name of a device[3]. If you do that, it does
9 > > not create a file in its database in /dev/.udevdb/
10 > >
11 > > If we can move away from some of our devfs-like names, we stand to
12 > > reclaim a lot of memory from everyone's machines. As an example, if we
13 > > drop all of the tty/pts/vc/vcc symlinks, and just go with the default
14 > > kernel name, we save 2.5Mb of space in tempfs/ramfs. I've done this on
15 > > my machines and everything seems to work just fine (it looks like
16 > > everything that was trying to use a tty node was just using the symlink
17 > > anyway.)
18 > >
19 > > So, anyone have any objections to me changing the default udev naming
20 > > scheme in this manner?
21 > >
22 >
23 > Fine with me. I assume we will need to keep the rcscript support for
24 > those die-hard 2.4 users still, but hopefully we can eventually drop
25 > that as well.
26
27 What rcscript support?
28
29 > > Next up, that loony block device naming scheme (more on that later...)
30 > >
31 >
32 > Heh. I hope that we will still at least just do the cdsymlinks stuff
33 > (just the /dev/cdrom, /dev/dvd, etc stuff) as that do make things a bit
34 > easier for multimedia stuff.
35
36 Yes, I don't see us dropping that, as it's just too useful :)
37
38 > > [3] HAL needs a patch to be able to handle this. It's posted on the
39 > > hal development mailing lists and will be checked in real-soon-now.
40 >
41 > I just think we need to make sure this is in first ...
42
43 The HAL patch? It's now in HAL's cvs tree, don't know when they will do
44 a new release.
45
46 > Lastly on an unrelated note ... I have a rule:
47 >
48 > -----
49 > # cat /etc/udev/rules.d/40-dm.rules
50 > KERNEL="dm-[0-9]*", PROGRAM="/sbin/devmap_name %M %m", NAME="mapper/%c", SYMLINK="%c"
51 > -----
52 >
53 > And in theory it should be the last rule to set the name ... however the
54 > default one in 50-udev.rules overrides it, and I have to add
55 > OPTIONS="last_rule"
56
57 Yes.
58
59 Want me to just change the default rule to yours?
60
61 thanks,
62
63 greg k-h
64 --
65 gentoo-dev@g.o mailing list

Replies

Subject Author
Re: [gentoo-dev] devfs is dead, let's move on Martin Schlemmer <azarah@g.o>