From: Peter Zijlstra <peterz@infradead.org>
To: gerald.schaefer@de.ibm.com
Cc: Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-s390 <linux-s390@vger.kernel.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>
Subject: Re: [PATCH] mutex: Introduce mutex_cpu_relax()
Date: Thu, 14 Oct 2010 17:55:29 +0200 [thread overview]
Message-ID: <1287071729.29097.278.camel@twins> (raw)
In-Reply-To: <1287070392.8344.15.camel@thinkpad>
On Thu, 2010-10-14 at 17:33 +0200, Gerald Schaefer wrote:
> From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
>
> The spinning mutex implementation uses cpu_relax() in busy loops as a
> compiler barrier. Depending on the architecture, cpu_relax() may do more
> than needed in this specific mutex spin loops. On System z we also give
> up the time slice of the virtual cpu in cpu_relax(), which prevents
> effective spinning on the mutex.
>
> This patch replaces cpu_relax() in the spinning mutex code with a new
> function mutex_cpu_relax(), which can be defined by each architecture
> that selects HAVE_MUTEX_CPU_RELAX. The default is still cpu_relax(), so
> this patch should not affect other architectures than System z for now.
Sure.. I'll take it.
next prev parent reply other threads:[~2010-10-14 15:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-14 15:33 [PATCH] mutex: Introduce mutex_cpu_relax() Gerald Schaefer
2010-10-14 15:55 ` Peter Zijlstra [this message]
2010-10-14 15:59 ` Peter Zijlstra
2010-10-14 17:31 ` Gerald Schaefer
2010-10-14 17:40 ` Gerald Schaefer
2010-10-14 22:13 ` Andrew Morton
2010-10-15 10:55 ` Gerald Schaefer
2010-10-15 11:07 ` [PATCH] mutex: Introduce arch_mutex_cpu_relax() Gerald Schaefer
2010-10-18 18:54 ` Peter Zijlstra
2010-10-19 12:24 ` Gerald Schaefer
2010-10-19 15:18 ` Gerald Schaefer
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