From: Jeff Garzik <jeff@garzik.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Jones <davej@redhat.com>, Robin Holt <holt@sgi.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Jack Steiner <steiner@americas.sgi.com>
Subject: Re: init's children list is long and slows reaping children.
Date: Tue, 10 Apr 2007 04:48:54 -0400 [thread overview]
Message-ID: <461B4F76.1010807@garzik.org> (raw)
In-Reply-To: <20070410014102.fd730911.akpm@linux-foundation.org>
Andrew Morton wrote:
> Well that obviously would be a dumb way to use keventd. One would need
> to do schedule_work(), kick off the reset then do schedule_delayed_work()
> to wait (or poll) for its termination.
Far too complex. See what Russell wrote, for instance.
When you are in a kernel thread, you can write more simple,
straightforward, easy-to-debug code that does
blah
msleep()
blah
rather than creating an insanely complicated state machine for the same
thing.
ESPECIALLY if you are already inside a state machine (the case with
libata PIO data xfer), you do not want to add another state machine
inside of that.
A great many uses of kernel threads are to simplify device reset and
polling in this way. I know; a year ago I audited every kernel thread,
because I was so frustrated with the per-CPU thread explosion.
Thus, rather than forcing authors to make their code more complex, we
should find another solution.
Jeff
next prev parent reply other threads:[~2007-04-10 8:49 UTC|newest]
Thread overview: 112+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-05 19:51 init's children list is long and slows reaping children Robin Holt
2007-04-05 20:57 ` Linus Torvalds
2007-04-06 0:51 ` Chris Snook
2007-04-06 1:03 ` Chris Snook
2007-04-06 1:29 ` Linus Torvalds
2007-04-06 2:15 ` Eric W. Biederman
2007-04-06 10:43 ` Robin Holt
2007-04-06 15:38 ` Eric W. Biederman
2007-04-06 16:31 ` Oleg Nesterov
2007-04-06 17:32 ` Ingo Molnar
2007-04-06 17:39 ` Roland Dreier
2007-04-06 18:04 ` Eric W. Biederman
2007-04-06 18:30 ` Eric W. Biederman
2007-04-06 19:18 ` [patch] sched: get rid of p->children use in show_task() Ingo Molnar
2007-04-06 19:22 ` Ingo Molnar
2007-04-10 13:48 ` init's children list is long and slows reaping children Ingo Molnar
2007-04-10 13:38 ` Oleg Nesterov
2007-04-10 15:00 ` Eric W. Biederman
2007-04-10 15:16 ` [PATCH] Only send pdeath_signal when getppid changes Eric W. Biederman
2007-04-10 16:37 ` Oleg Nesterov
2007-04-10 17:41 ` Eric W. Biederman
2007-04-10 17:48 ` Roland McGrath
2007-04-11 3:17 ` Albert Cahalan
2007-04-10 14:51 ` init's children list is long and slows reaping children Eric W. Biederman
2007-04-10 15:06 ` Ingo Molnar
2007-04-10 15:22 ` Eric W. Biederman
2007-04-10 15:53 ` Ingo Molnar
2007-04-10 16:17 ` Eric W. Biederman
2007-04-11 6:20 ` [patch] uninline remove/add_parent() APIs Ingo Molnar
2007-04-11 7:00 ` Eric W. Biederman
2007-04-11 22:06 ` Andrew Morton
2007-04-12 10:45 ` Eric W. Biederman
2007-04-12 22:50 ` Roland McGrath
2007-04-10 16:44 ` init's children list is long and slows reaping children Oleg Nesterov
2007-04-11 19:55 ` Bill Davidsen
2007-04-11 20:17 ` Eric W. Biederman
2007-04-11 21:24 ` Bill Davidsen
2007-04-11 20:19 ` Oleg Nesterov
2007-04-06 18:02 ` Eric W. Biederman
2007-04-06 18:21 ` Davide Libenzi
2007-04-06 18:56 ` Eric W. Biederman
2007-04-06 19:16 ` Davide Libenzi
2007-04-06 19:19 ` Ingo Molnar
2007-04-06 21:29 ` Davide Libenzi
2007-04-06 21:51 ` Linus Torvalds
2007-04-06 22:31 ` Davide Libenzi
2007-04-06 22:46 ` Linus Torvalds
2007-04-06 22:59 ` Davide Libenzi
2007-04-09 8:28 ` Ingo Molnar
2007-04-09 18:09 ` Bill Davidsen
2007-04-09 19:28 ` Kyle Moffett
2007-04-09 19:51 ` Linus Torvalds
2007-04-09 20:03 ` Davide Libenzi
2007-04-10 15:12 ` Bill Davidsen
2007-04-10 19:17 ` Davide Libenzi
2007-04-09 20:00 ` Eric W. Biederman
2007-04-06 16:41 ` Robin Holt
2007-04-09 17:37 ` Chris Snook
2007-04-06 18:05 ` Christoph Hellwig
2007-04-06 19:39 ` Eric W. Biederman
2007-04-06 22:38 ` Jeff Garzik
2007-04-06 22:51 ` Linus Torvalds
2007-04-06 23:37 ` Jeff Garzik
2007-04-11 7:28 ` Nick Piggin
2007-04-10 0:23 ` Andrew Morton
2007-04-10 0:48 ` Eric W. Biederman
2007-04-10 1:15 ` Andrew Morton
2007-04-10 6:53 ` Jeff Garzik
2007-04-10 9:42 ` Robin Holt
2007-04-10 1:59 ` Dave Jones
2007-04-10 2:30 ` Andrew Morton
2007-04-10 2:46 ` Linus Torvalds
2007-04-10 7:07 ` Jeff Garzik
2007-04-10 22:20 ` Ingo Oeser
2007-04-10 5:07 ` Alexey Dobriyan
2007-04-10 5:21 ` Dave Jones
2007-04-10 6:09 ` Torsten Kaiser
2007-04-10 7:08 ` Jeff Garzik
2007-04-10 7:05 ` Jeff Garzik
2007-04-10 7:37 ` Andrew Morton
2007-04-10 8:33 ` Jeff Garzik
2007-04-10 8:41 ` Andrew Morton
2007-04-10 8:48 ` Jeff Garzik [this message]
2007-04-10 22:35 ` Ingo Oeser
2007-04-10 16:35 ` Matt Mackall
2007-04-10 7:44 ` Russell King
2007-04-10 8:16 ` Jeff Garzik
2007-04-10 8:59 ` Ingo Molnar
2007-04-10 9:33 ` Jeff Garzik
-- strict thread matches above, loose matches on Subject: below --
2007-04-06 8:42 Oleg Nesterov
2007-04-06 9:10 ` Eric W. Biederman
2007-04-06 9:44 ` Oleg Nesterov
2007-04-06 15:45 ` Eric W. Biederman
2007-04-06 15:47 ` Oleg Nesterov
2007-04-06 17:16 ` Linus Torvalds
2007-04-06 17:27 ` Ingo Molnar
2007-04-06 17:31 ` Ingo Molnar
2007-04-06 17:34 ` Eric W. Biederman
2007-04-06 19:06 ` H. Peter Anvin
2007-04-06 19:15 ` Eric W. Biederman
2007-04-06 19:21 ` H. Peter Anvin
2007-04-06 21:04 ` Jeremy Fitzhardinge
2007-04-06 21:07 ` H. Peter Anvin
2007-04-06 19:36 ` Oleg Nesterov
2007-04-06 19:43 ` Ingo Molnar
2007-04-06 20:01 ` Oleg Nesterov
2007-04-06 20:21 ` Ingo Molnar
2007-04-06 19:47 ` Oleg Nesterov
2007-04-06 19:59 ` Eric W. Biederman
2007-04-07 20:31 ` Oleg Nesterov
2007-04-08 0:38 ` Eric W. Biederman
2007-04-08 15:46 ` Oleg Nesterov
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