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From: Ingo Molnar <mingo@elte.hu>
To: Nicolas Pitre <nico@cam.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
	Arjan van de Ven <arjan@infradead.org>,
	Russell King <rmk+lkml@arm.linux.org.uk>
Subject: Re: [patch 1/3] mutex subsystem: trylock
Date: Wed, 28 Dec 2005 08:48:57 +0100	[thread overview]
Message-ID: <20051228074857.GA4600@elte.hu> (raw)
In-Reply-To: <Pine.LNX.4.64.0512271439380.3309@localhost.localdomain>


* Nicolas Pitre <nico@cam.org> wrote:

> > here we go to great trouble trying to avoid the 'slowpath', while we 
> > unconditionally force the next unlock into the slowpath! So we have 
> > not won anything. (on a cycle count basis it's probably even a net 
> > loss)
> 
> I disagree.  [...elaborate analysis of the code ...]

you are right, it should work fine, and should be optimal. I'll add your 
xchg variant to mutex-xchg.h.

	Ingo

  reply	other threads:[~2005-12-28  7:49 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-12-23 16:16 [patch 00/11] mutex subsystem, -V7 Ingo Molnar
2005-12-24  5:15 ` Nicolas Pitre
2005-12-24  5:23   ` Nicolas Pitre
2005-12-26 19:24 ` Nicolas Pitre
2005-12-26 19:25 ` [patch 1/3] mutex subsystem: trylock Nicolas Pitre
2005-12-27 11:51   ` Ingo Molnar
2005-12-27 20:47     ` Nicolas Pitre
2005-12-28  7:48       ` Ingo Molnar [this message]
2005-12-28  8:13         ` Ingo Molnar
2005-12-28 16:29           ` Nicolas Pitre
2005-12-28 17:09             ` Ingo Molnar
2005-12-27 12:05   ` Arjan van de Ven
2005-12-27 13:15     ` Ingo Molnar
2005-12-29  4:06       ` Nicolas Pitre
2005-12-29  8:33         ` Ingo Molnar
2005-12-29  9:01           ` Nick Piggin
2005-12-29 17:15             ` Nicolas Pitre
2005-12-30  2:05               ` Nick Piggin
2005-12-29 16:46           ` Nicolas Pitre
2005-12-29  3:22     ` Nicolas Pitre
2005-12-26 19:25 ` [patch 2/3] mutex subsystem: fastpath inlining Nicolas Pitre
2005-12-27 11:55   ` Ingo Molnar
2005-12-27 21:59     ` Nicolas Pitre
2005-12-28  7:41       ` Ingo Molnar
2005-12-29  2:53         ` Nicolas Pitre
2005-12-29  8:41           ` Ingo Molnar
2006-01-06 21:20             ` Nicolas Pitre
2005-12-26 19:26 ` [patch 3/3] mutex subsystem: inline mutex_is_locked() Nicolas Pitre
2005-12-27 11:37   ` Ingo Molnar

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