From: Ingo Molnar <mingo@kernel.org>
Date: Tue, 20 Nov 2012 12:02:51 +0000 (+0100)
Subject: x86/mm: Don't flush the TLB on #WP pmd fixups
X-Git-Tag: v3.9-rc1~108^2~18^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5e4bf1a55da976a5ed60901bb8801f1024ef9774;p=pandora-kernel.git

x86/mm: Don't flush the TLB on #WP pmd fixups

If we have a write protection #PF and fix up the pmd then the
hugetlb code [the only user of pmdp_set_access_flags], in its
do_huge_pmd_wp_page() page fault resolution function calls
pmdp_set_access_flags() to mark the pmd permissive again,
and flushes the TLB.

This TLB flush is unnecessary: a flush on #PF is guaranteed on
most (all?) x86 CPUs, and even in the worst-case we'll generate
a spurious fault.

So remove it.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Link: http://lkml.kernel.org/r/20121120120251.GA15742@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

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