From: Michel Lespinasse <walken@google.com>
Date: Sat, 23 Feb 2013 00:35:56 +0000 (-0800)
Subject: mm: accelerate mm_populate() treatment of THP pages
X-Git-Tag: v3.9-rc1~99^2~11
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=240aadeedc4a89fc44623f8ce4ca46bda73db07e;p=pandora-kernel.git

mm: accelerate mm_populate() treatment of THP pages

This change adds a follow_page_mask function which is equivalent to
follow_page, but with an extra page_mask argument.

follow_page_mask sets *page_mask to HPAGE_PMD_NR - 1 when it encounters
a THP page, and to 0 in other cases.

__get_user_pages() makes use of this in order to accelerate populating
THP ranges - that is, when both the pages and vmas arrays are NULL, we
don't need to iterate HPAGE_PMD_NR times to cover a single THP page (and
we also avoid taking mm->page_table_lock that many times).

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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