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From: Ingo Molnar <mingo@elte.hu>
To: David Howells <dhowells@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	tj@kernel.org, akpm@linux-foundation.org,
	linux-kernel@vger.kernel.org,
	Rusty Russell <rusty@rustcorp.com.au>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Suresh Siddha <suresh.b.siddha@intel.com>
Subject: Re: [PATCH] FRV: Fix the section attribute on UP DECLARE_PER_CPU()
Date: Wed, 22 Apr 2009 11:12:26 +0200	[thread overview]
Message-ID: <20090422091226.GA18226@elte.hu> (raw)
In-Reply-To: <30674.1240338986@redhat.com>


* David Howells <dhowells@redhat.com> wrote:

> Any idea what this:
> 
> 	#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)
> 
> is intended for?

it is a mixed type of percpu variable: which is per CPU but which 
can (and will) also be accessed from other CPUs. This way we 
basically cache-line align it and make sure nearby percpu variables 
dont get caught up in any cacheline bounces. It was introduced a 
couple of years ago.

	Ingo

      reply	other threads:[~2009-04-22  9:14 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-14 16:10 [PATCH] FRV: Fix the section attribute on UP DECLARE_PER_CPU() David Howells
2009-04-14 16:57 ` Linus Torvalds
2009-04-14 17:57   ` David Howells
2009-04-14 18:06     ` Linus Torvalds
2009-04-15 10:24       ` David Howells
2009-04-15 15:19         ` Linus Torvalds
2009-04-15 16:49           ` Ingo Molnar
2009-04-15 11:40       ` David Howells
2009-04-15 12:03         ` Ingo Molnar
2009-04-15 13:20           ` David Howells
2009-04-15 14:09             ` Ingo Molnar
2009-04-15 15:09               ` David Howells
2009-04-15 16:54                 ` Ingo Molnar
2009-04-21 18:36                   ` David Howells
2009-04-22  9:12                     ` Ingo Molnar [this message]

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