vmscan: activate executable pages after first usage
authorKonstantin Khlebnikov <khlebnikov@openvz.org>
Tue, 10 Jan 2012 23:07:03 +0000 (15:07 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 11 Jan 2012 00:30:41 +0000 (16:30 -0800)
Logic added in commit 8cab4754d24a0 ("vmscan: make mapped executable pages
the first class citizen") was noticeably weakened in commit
645747462435d84 ("vmscan: detect mapped file pages used only once").

Currently these pages can become "first class citizens" only after second
usage.  After this patch page_check_references() will activate they after
first usage, and executable code gets yet better chance to stay in memory.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/vmscan.c

index 753c1e6755f098f929bc58ed732e6548cf85b7df..753a2dc300b98347fd6e9d6f61cc0d1ebf0f71cf 100644 (file)
@@ -718,6 +718,12 @@ static enum page_references page_check_references(struct page *page,
                if (referenced_page || referenced_ptes > 1)
                        return PAGEREF_ACTIVATE;
 
+               /*
+                * Activate file-backed executable pages after first usage.
+                */
+               if (vm_flags & VM_EXEC)
+                       return PAGEREF_ACTIVATE;
+
                return PAGEREF_KEEP;
        }