From: Zachary Amsden <zach@vmware.com>
Date: Wed, 2 May 2007 17:27:19 +0000 (+0200)
Subject: [PATCH] i386: pte xchg optimization
X-Git-Tag: v2.6.22-rc1~1011^2~37
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=142dd975911fdd82b1b6f6617cd20ac90a8ccf00;p=pandora-kernel.git

[PATCH] i386: pte xchg optimization

In situations where page table updates need only be made locally, and there is
no cross-processor A/D bit races involved, we need not use the heavyweight
xchg instruction to atomically fetch and clear page table entries.  Instead,
we can just read and clear them directly.

This introduces a neat optimization for non-SMP kernels; drop the atomic xchg
operations from page table updates.

Thanks to Michel Lespinasse for noting this potential optimization.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
---

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