From: Zachary Amsden <zach@vmware.com>
Date: Sun, 1 Oct 2006 06:29:36 +0000 (-0700)
Subject: [PATCH] paravirt: optimize ptep establish for pae
X-Git-Tag: v2.6.19-rc1~496
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d6d861e3c963b4077c83e078e3e300c4b81f93e7;p=pandora-kernel.git

[PATCH] paravirt: optimize ptep establish for pae

The ptep_establish macro is only used on user-level PTEs, for P->P mapping
changes.  Since these always happen under protection of the pagetable lock,
the strong synchronization of a 64-bit cmpxchg is not needed, in fact, not
even a lock prefix needs to be used.  We can simply instead clear the P-bit,
followed by a normal set.  The write ordering is still important to avoid the
possibility of the TLB snooping a partially written PTE and getting a bad
mapping installed.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

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