From: Michel Lespinasse <walken@google.com>
Date: Thu, 28 Feb 2013 01:02:44 +0000 (-0800)
Subject: mm: accelerate munlock() treatment of THP pages
X-Git-Tag: v3.9-rc1~46^2~157
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ff6a6da60;p=pandora-kernel.git

mm: accelerate munlock() treatment of THP pages

munlock_vma_pages_range() was always incrementing addresses by PAGE_SIZE
at a time.  When munlocking THP pages (or the huge zero page), this
resulted in taking the mm->page_table_lock 512 times in a row.

We can do better by making use of the page_mask returned by
follow_page_mask (for the huge zero page case), or the size of the page
munlock_vma_page() operated on (for the true THP page case).

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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