The patch titled vmscan: promote shared file mapped pages has been added to the -mm tree. Its filename is vmscan-promote-shared-file-mapped-pages.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: vmscan: promote shared file mapped pages From: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx> Commit 645747462435 ("vmscan: detect mapped file pages used only once") greatly decreases lifetime of single-used mapped file pages. Unfortunately it also decreases life time of all shared mapped file pages. Because after commit bf3f3bc5e7347 ("mm: don't mark_page_accessed in fault path") page-fault handler does not mark page active or even referenced. Thus page_check_references() activates file page only if it was used twice while it stays in inactive list, meanwhile it activates anon pages after first access. Inactive list can be small enough, this way reclaimer can accidentally throw away any widely used page if it wasn't used twice in short period. After this patch page_check_references() also activate file mapped page at first inactive list scan if this page is already used multiple times via several ptes. I found this while trying to fix degragation in rhel6 (~2.6.32) from rhel5 (~2.6.18). There a complete mess with >100 web/mail/spam/ftp containers, they share all their files but there a lot of anonymous pages: ~500mb shared file mapped memory and 15-20Gb non-shared anonymous memory. In this situation major-pagefaults are very costly, because all containers share the same page. In my load kernel created a disproportionate pressure on the file memory, compared with the anonymous, they equaled only if I raise swappiness up to 150 =) These patches actually wasn't helped a lot in my problem, but I saw noticable (10-20 times) reduce in count and average time of major-pagefault in file-mapped areas. Actually both patches are fixes for commit v2.6.33-5448-g6457474, because it was aimed at one scenario (singly used pages), but it breaks the logic in other scenarios (shared and/or executable pages) Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx> Acked-by: Pekka Enberg <penberg@xxxxxxxxxx> Acked-by: Minchan Kim <minchan.kim@xxxxxxxxx> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Cc: Wu Fengguang <fengguang.wu@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Nick Piggin <npiggin@xxxxxxxxx> Cc: Mel Gorman <mel@xxxxxxxxx> Cc: Shaohua Li <shaohua.li@xxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN mm/vmscan.c~vmscan-promote-shared-file-mapped-pages mm/vmscan.c --- a/mm/vmscan.c~vmscan-promote-shared-file-mapped-pages +++ a/mm/vmscan.c @@ -715,7 +715,7 @@ static enum page_references page_check_r */ SetPageReferenced(page); - if (referenced_page) + if (referenced_page || referenced_ptes > 1) return PAGEREF_ACTIVATE; return PAGEREF_KEEP; _ Patches currently in -mm which might be from khlebnikov@xxxxxxxxxx are vmscan-fix-initial-shrinker-size-handling.patch vmscan-use-atomic-long-for-shrinker-batching.patch vmscan-use-atomic-long-for-shrinker-batching-fix.patch vmscan-promote-shared-file-mapped-pages.patch vmscan-activate-executable-pages-after-first-usage.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html