From: Mel Gorman <mgorman@suse.de>
Date: Mon, 7 Oct 2013 10:28:48 +0000 (+0100)
Subject: mm: Do not flush TLB during protection change if !pte_present && !migration_entry
X-Git-Tag: omap-for-v3.13/fixes-for-merge-window-take2~40^2~80
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e920e14ca29b0b2a981cfc90e4e20edd6f078d19;p=pandora-kernel.git

mm: Do not flush TLB during protection change if !pte_present && !migration_entry

NUMA PTE scanning is expensive both in terms of the scanning itself and
the TLB flush if there are any updates. Currently non-present PTEs are
accounted for as an update and incurring a TLB flush where it is only
necessary for anonymous migration entries. This patch addresses the
problem and should reduce TLB flushes.

Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-11-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

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