Commit be22aece authored Mar 09, 2012 by Hugh Dickins Committed by Linus Torvalds Mar 09, 2012

memcg: revert fix to mapcount check for this release

Respectfully revert commit e6ca7b89 "memcg: fix mapcount check
in move charge code for anonymous page" for the 3.3 release, so that
it behaves exactly like releases 2.6.35 through 3.2 in this respect.

Horiguchi-san's commit is correct in itself, 1 makes much more sense
than 2 in that check; but it does not go far enough - swapcount
should be considered too - if we really want such a check at all.

We appear to have reached agreement now, and expect that 3.4 will
remove the mapcount check, but had better not make 3.3 different.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a7f4255f

mm/memcontrol.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -5075,7 +5075,7 @@ static struct page mc_handle_present_pte(struct vm_area_struct vma,
		return NULL;
		if (PageAnon(page)) {
		/* we don't move shared anon */
		if (!move_anon() \|\| page_mapcount(page) > 1)
		if (!move_anon() \|\| page_mapcount(page) > 2)
		return NULL;
		} else if (!move_file())
		/* we ignore mapcount for file pages */

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