From: Daniel Walker <dwalker@mvista.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>,
Roland Dreier <rdreier@cisco.com>, Ingo Molnar <mingo@elte.hu>,
Matthew Wilcox <matthew@wil.cx>, Ingo Oeser <ioe-lkml@rameria.de>,
linux-kernel@vger.kernel.org, Linus Torvalds <torvalds@osdl.org>
Subject: Re: [PATCH] Replace completions with semaphores
Date: Mon, 14 Apr 2008 11:09:12 -0700 [thread overview]
Message-ID: <1208196552.4877.30.camel@localhost.localdomain> (raw)
In-Reply-To: <1208195673.7164.2.camel@twins>
On Mon, 2008-04-14 at 19:54 +0200, Peter Zijlstra wrote:
> On Mon, 2008-04-14 at 19:46 +0200, Andi Kleen wrote:
> > Peter Zijlstra <peterz@infradead.org> writes:
> > >
> > > Yeah, I would open code it. But this is indeed a sane usage of the
> > > counting semaphore because there is no priority inversion.
> >
> > But when you open code that, how is it different from just having
> > semaphores?
>
> Because we can then eventually get rid of semaphores, so those people
> cannot mistakenly use them. Its just too easy to create prio inversion
> with them around.
I'm not for open coding anything .. This "writes in flight" type code
happens often enough we should have something that covers it..
completions come fairly close (since they're just like locked
semaphores) only it's not easy to initialize them to allow multiple
completes before the waiting starts..
Daniel
next prev parent reply other threads:[~2008-04-14 18:09 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-11 21:00 [PATCH] Replace completions with semaphores Matthew Wilcox
2008-04-12 6:43 ` Daniel Walker
2008-04-12 10:31 ` Ingo Oeser
2008-04-12 12:24 ` Peter Zijlstra
2008-04-12 17:26 ` Matthew Wilcox
2008-04-12 18:01 ` Daniel Walker
2008-04-12 18:05 ` Peter Zijlstra
2008-04-12 19:04 ` Matthew Wilcox
2008-04-12 19:16 ` Peter Zijlstra
2008-04-12 19:53 ` Roland Dreier
2008-04-12 20:47 ` Matthew Wilcox
2008-04-13 7:08 ` Ingo Molnar
2008-04-13 12:57 ` Matthew Wilcox
2008-04-14 15:39 ` Ingo Molnar
2008-04-14 15:58 ` Roland Dreier
2008-04-14 16:32 ` Peter Zijlstra
2008-04-14 16:56 ` Arjan van de Ven
2008-04-14 17:50 ` Matthew Wilcox
2008-04-14 17:46 ` Andi Kleen
2008-04-14 17:54 ` Peter Zijlstra
2008-04-14 18:09 ` Daniel Walker [this message]
2008-04-14 19:16 ` Andi Kleen
2008-04-15 6:18 ` Bart Van Assche
2008-04-15 6:46 ` Peter Zijlstra
2008-04-15 7:17 ` Bart Van Assche
2008-04-15 8:44 ` Peter Zijlstra
2008-04-15 13:15 ` Bart Van Assche
2008-04-15 16:09 ` Linus Torvalds
2008-04-15 16:27 ` Andi Kleen
2008-04-15 16:57 ` Linus Torvalds
2008-04-15 17:05 ` Ingo Molnar
2008-04-15 18:50 ` Matthew Wilcox
2008-04-16 12:37 ` Ingo Molnar
2008-04-16 12:50 ` Andi Kleen
2008-04-16 12:59 ` Killable stat/readdir Matthew Wilcox
2008-04-15 17:15 ` [PATCH] Replace completions with semaphores Andi Kleen
2008-04-15 17:26 ` Linus Torvalds
2008-04-15 17:41 ` Matthew Wilcox
2008-04-15 18:14 ` Linus Torvalds
2008-04-16 16:07 ` Ingo Oeser
2008-04-16 16:16 ` Matthew Wilcox
2008-04-16 16:31 ` Oliver Neukum
2008-04-16 16:34 ` Matthew Wilcox
2008-04-16 16:42 ` Oliver Neukum
2008-04-16 16:44 ` Matthew Wilcox
2008-04-16 16:47 ` Roland Dreier
2008-04-16 16:50 ` Arjan van de Ven
2008-04-16 16:58 ` Matthew Wilcox
2008-04-16 17:08 ` Arjan van de Ven
2008-04-16 17:12 ` Matthew Wilcox
2008-04-16 18:10 ` Matthew Wilcox
2008-04-14 19:16 ` Alan Cox
2008-04-13 14:55 ` Bart Van Assche
2008-04-14 17:12 ` API documentation (was [PATCH] Replace completions with semaphores) Jonathan Corbet
2008-04-14 17:33 ` Peter Zijlstra
2008-04-14 18:38 ` Bart Van Assche
2008-04-13 13:55 ` [PATCH] Replace completions with semaphores Bart Van Assche
2008-04-13 14:22 ` Matthew Wilcox
2008-04-13 7:05 ` Ingo Molnar
2008-04-13 12:52 ` Matthew Wilcox
2008-04-14 15:41 ` Ingo Molnar
2008-04-14 17:46 ` Matthew Wilcox
2008-04-14 16:54 ` Jens Axboe
[not found] <ahyFC-2bu-25@gated-at.bofh.it>
[not found] ` <ahUPJ-8rN-1@gated-at.bofh.it>
[not found] ` <ai4vO-2Rp-19@gated-at.bofh.it>
[not found] ` <ai9Yw-5uh-7@gated-at.bofh.it>
[not found] ` <aiz6z-OZ-31@gated-at.bofh.it>
[not found] ` <aizgp-151-25@gated-at.bofh.it>
[not found] ` <aizSW-2Ar-17@gated-at.bofh.it>
[not found] ` <aiAYF-5e7-19@gated-at.bofh.it>
[not found] ` <aiB8o-5A7-17@gated-at.bofh.it>
[not found] ` <aiCnR-7k-39@gated-at.bofh.it>
[not found] ` <aiMGu-7f0-7@gated-at.bofh.it>
2008-04-16 10:22 ` Bodo Eggert
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