Re: updating kernel to 2.6.13-rc1 from 2.6.12 + CONFIG_DEVFS_FS + empty /dev

[Willy Tarreau <willy@w.ods.org>]

On Sat, Jul 02, 2005 at 01:13:58PM -0700, Mike Bell wrote:
> On Sat, Jul 02, 2005 at 12:03:49PM +0200, Willy Tarreau wrote:
> > They cost almost nothing, and in all cases, far less than the required code
> > to autodetect them.
> 
> I beg to differ on that. As ndevfs has shown, the code required to
> create a device node from kernel space is actually very minimal, when
> you utilize all the infrastructure already available to you in the
> kernel. libfs has most of what you need, the rest is easily stolen from
> ramfs. Almost undoubtebly much less than all those device nodes,
> especially when you consider the need to be able to perform chown/chmod
> on nodes (thus they can't be stored in the read-only flash image, but
> must instead be created at each boot on a kernel-generated filesystem
> like ramfs)

Well, here on my firewall, the /.preinit script is 1.7 kB and the init
binary which does everything (mkdir,mknod,chmod,chown,mount,...) is 5.6 kB.
I doubt you can enable devfs in a kernel for less than 8 kB. One /tmpfs
entry consumes about 600 bytes of RAM, which is still fairly acceptable
IMHO.

> devfs not utilizing it is perfectly explainable by the fact none of it
> was around way back when devfs was created. Back then kernel generated
> filesystems were proc, proc and proc. proc is pretty ugly too.

Regards,
Willy