From: Ingo Molnar <mingo@elte.hu>
To: Paul Mackerras <paulus@samba.org>
Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH] Define __raw_get_cpu_var and use it
Date: Wed, 10 May 2006 09:09:29 +0200 [thread overview]
Message-ID: <20060510070929.GA23414@elte.hu> (raw)
In-Reply-To: <17505.24133.491523.358882@cargo.ozlabs.ibm.com>
* Paul Mackerras <paulus@samba.org> wrote:
> There are several instances of per_cpu(foo, raw_smp_processor_id()),
> which is semantically equivalent to __get_cpu_var(foo) but without the
> warning that smp_processor_id() can give if CONFIG_DEBUG_PREEMPT is
> enabled. For those architectures with optimized per-cpu
> implementations, namely ia64, powerpc, s390, sparc64 and x86_64,
> per_cpu() turns into more and slower code than __get_cpu_var(), so it
> would be preferable to use __get_cpu_var on those platforms.
>
> This defines a __raw_get_cpu_var(x) macro which turns into per_cpu(x,
> raw_smp_processor_id()) on architectures that use the generic per-cpu
> implementation, and turns into __get_cpu_var(x) on the architectures
> that have an optimized per-cpu implementation.
>
> Signed-off-by: Paul Mackerras <paulus@samba.org>
i made the original raw_smp_processor_id() changes and i never liked the
per_cpu() open-coding it introduced. Your patch solves this problem
nicely.
Acked-by: Ingo Molnar <mingo@elte.hu>
Ingo
next prev parent reply other threads:[~2006-05-10 7:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-05-10 3:30 [PATCH] Define __raw_get_cpu_var and use it Paul Mackerras
2006-05-10 6:17 ` David S. Miller
2006-05-10 7:09 ` Ingo Molnar [this message]
2006-05-10 8:39 ` Martin Schwidefsky
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