From: Oliver Neukum <oliver@neukum.org>
To: Greg KH <greg@kroah.com>, Mike Bell <kernel@mikebell.org>,
Dmitry Torokhov <dtor_core@ameritech.net>,
linux-kernel@vger.kernel.org
Subject: Re: [ANNOUNCE] ndevfs - a "nano" devfs
Date: Wed, 29 Jun 2005 18:22:29 +0200 [thread overview]
Message-ID: <200506291822.29351.oliver@neukum.org> (raw)
In-Reply-To: <20050629160659.GA23594@kroah.com>
Am Mittwoch, 29. Juni 2005 18:06 schrieben Sie:
> On Wed, Jun 29, 2005 at 08:41:29AM +0200, Oliver Neukum wrote:
> > What devfs and udev can do, and a static dev cannot, is names independent
> > of order of detection.
>
> devfs can not do that.
Why not?
> > As for ressources, it is an illusion to think that user space means
> > less ressources. A demon means page tables and a kernel stack. That
> > 12K unswappable memory in the best case.
>
> You don't have to run the udevd process if you are worried about an
What about events arriving out of order?
> extra process in your kernel tables. Although this is the first time I
> have heard anyone voice the "oh no, not another userspace task running"
> point :)
Well, you should have. 16K is a more realistic figure. Tasks have their cost.
In fact:
root 1 0.0 0.0 684 248 ? S 16:58 0:01 init [5]
root 2 0.0 0.0 0 0 ? SN 16:58 0:00 [ksoftirqd/0]
root 3 0.0 0.0 0 0 ? S< 16:58 0:00 [events/0]
root 4 0.0 0.0 0 0 ? S< 16:58 0:00 [khelper]
root 5 0.0 0.0 0 0 ? S< 16:58 0:00 [kthread]
<snip>
root 3424 0.0 0.1 2032 632 tty3 Ss+ 16:59 0:00 /sbin/mingetty tty3
root 3425 0.0 0.1 2032 632 tty4 Ss+ 16:59 0:00 /sbin/mingetty tty4
root 3426 0.0 0.1 2032 632 tty5 Ss+ 16:59 0:00 /sbin/mingetty tty5
root 3427 0.0 0.1 2032 632 tty6 Ss+ 16:59 0:00 /sbin/mingetty tty6
Counting this I arrive at 51*16K = 816K. That's a whole lot of unswappable
memory. Thinking user space cheap is an automatic reflex these days. It's
sometimes misleading like all blind reflexes.
It makes me feel a fool for caring about __init and __exit.
Regards
Oliver
next prev parent reply other threads:[~2005-06-29 16:23 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-24 8:18 [ANNOUNCE] ndevfs - a "nano" devfs Greg KH
2005-06-24 12:23 ` Michael Tokarev
2005-06-24 15:16 ` Greg KH
2005-06-24 15:40 ` Michael Tokarev
2005-06-24 16:26 ` Greg KH
2005-06-24 14:32 ` Bill Gatliff
2005-06-24 15:17 ` Steven Rostedt
2005-06-24 15:20 ` Greg KH
2005-06-24 17:10 ` Michael Tokarev
2005-06-24 17:10 ` Bill Gatliff
2005-06-28 7:40 ` Greg KH
2005-06-24 19:05 ` Mike Bell
2005-06-24 21:55 ` J.A. Magallon
2005-06-24 19:22 ` Alexey Dobriyan
2005-06-25 0:57 ` Kyle Moffett
2005-06-25 7:37 ` Denis Vlasenko
2005-06-28 7:41 ` Greg KH
2005-06-28 19:56 ` Tom Rini
2005-06-28 21:08 ` Olaf Hering
2005-06-28 21:25 ` Tom Rini
2005-06-28 22:08 ` Michael Tokarev
2005-06-28 22:23 ` Tom Rini
2005-06-25 22:15 ` Matt Mackall
2005-06-25 23:43 ` Greg KH
2005-06-26 8:23 ` Russell King
2005-06-28 3:36 ` Greg KH
2005-06-27 7:19 ` Mike Bell
2005-06-27 22:35 ` Dmitry Torokhov
2005-06-27 23:26 ` Mike Bell
2005-06-28 7:40 ` Greg KH
2005-06-28 9:08 ` Mike Bell
2005-06-28 9:21 ` Arjan van de Ven
2005-06-28 9:40 ` Mike Bell
2005-06-28 21:49 ` Jim Crilly
2005-06-28 22:23 ` Mike Bell
2005-06-28 23:43 ` Jim Crilly
2005-06-29 0:12 ` Mike Bell
2005-06-29 0:39 ` David Lang
2005-06-29 0:53 ` Mike Bell
2005-06-28 12:00 ` Oliver Neukum
2005-06-28 20:08 ` Greg KH
2005-06-29 6:41 ` Oliver Neukum
2005-06-29 16:06 ` Greg KH
2005-06-29 16:22 ` Oliver Neukum [this message]
[not found] ` <200506270819.20108.arnd@arndb.de>
2005-06-28 3:46 ` Greg KH
[not found] <OF831AC472.851744FE-ON8025702A.004A57EC-8025702A.004B5AE9@sophos.com>
2005-06-24 15:23 ` Greg KH
2005-06-24 15:32 tvrtko.ursulin
2005-06-24 16:27 ` Greg KH
2005-06-27 15:17 Adam J. Richter
2005-06-27 15:21 Adam J. Richter
2005-06-27 23:27 ` J.A. Magallon
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