vmscan: activate executable pages after first usage

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 <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Wu Fengguang <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Shaohua Li <[email protected]>
Cc: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 753c1e6755f098f929bc58ed732e6548cf85b7df..753a2dc300b98347fd6e9d6f61cc0d1ebf0f71cf 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -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;
        }