git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 0cee34fd72c582b4f8ad8ce00645b75fb4168199 Mon Sep 17 00:00:00 2001
   2 From: Mel Gorman <mgorman@suse.de>
   3 Date: Thu, 12 Jan 2012 17:19:49 -0800
   4 Subject: mm: vmscan: check if reclaim should really abort even if compaction_ready() is true for one zone
   5
   6 From: Mel Gorman <mgorman@suse.de>
   7
   8 commit 0cee34fd72c582b4f8ad8ce00645b75fb4168199 upstream.
   9
  10 Stable note: Not tracked on Bugzilla. THP and compaction was found to
  11         aggressively reclaim pages and stall systems under different
  12         situations that was addressed piecemeal over time.
  13
  14 If compaction can proceed for a given zone, shrink_zones() does not
  15 reclaim any more pages from it.  After commit [e0c2327: vmscan: abort
  16 reclaim/compaction if compaction can proceed], do_try_to_free_pages()
  17 tries to finish as soon as possible once one zone can compact.
  18
  19 This was intended to prevent slabs being shrunk unnecessarily but there
  20 are side-effects.  One is that a small zone that is ready for compaction
  21 will abort reclaim even if the chances of successfully allocating a THP
  22 from that zone is small.  It also means that reclaim can return too early
  23 even though sc->nr_to_reclaim pages were not reclaimed.
  24
  25 This partially reverts the commit until it is proven that slabs are really
  26 being shrunk unnecessarily but preserves the check to return 1 to avoid
  27 OOM if reclaim was aborted prematurely.
  28
  29 [aarcange@redhat.com: This patch replaces a revert from Andrea]
  30 Signed-off-by: Mel Gorman <mgorman@suse.de>
  31 Reviewed-by: Rik van Riel <riel@redhat.com>
  32 Cc: Andrea Arcangeli <aarcange@redhat.com>
  33 Cc: Minchan Kim <minchan.kim@gmail.com>
  34 Cc: Dave Jones <davej@redhat.com>
  35 Cc: Jan Kara <jack@suse.cz>
  36 Cc: Andy Isaacson <adi@hexapodia.org>
  37 Cc: Nai Xia <nai.xia@gmail.com>
  38 Cc: Johannes Weiner <jweiner@redhat.com>
  39 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  40 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  41 Signed-off-by: Mel Gorman <mgorman@suse.de>
  42 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  43
  44 ---
  45  mm/vmscan.c |   19 +++++++++----------
  46  1 file changed, 9 insertions(+), 10 deletions(-)
  47
  48 --- a/mm/vmscan.c
  49 +++ b/mm/vmscan.c
  50 @@ -2129,7 +2129,8 @@ static inline bool compaction_ready(stru
  51   *
  52   * This function returns true if a zone is being reclaimed for a costly
  53   * high-order allocation and compaction is ready to begin. This indicates to
  54 - * the caller that it should retry the allocation or fail.
  55 + * the caller that it should consider retrying the allocation instead of
  56 + * further reclaim.
  57   */
  58  static bool shrink_zones(int priority, struct zonelist *zonelist,
  59                                         struct scan_control *sc)
  60 @@ -2138,7 +2139,7 @@ static bool shrink_zones(int priority, s
  61         struct zone *zone;
  62         unsigned long nr_soft_reclaimed;
  63         unsigned long nr_soft_scanned;
  64 -       bool should_abort_reclaim = false;
  65 +       bool aborted_reclaim = false;
  66
  67         for_each_zone_zonelist_nodemask(zone, z, zonelist,
  68                                         gfp_zone(sc->gfp_mask), sc->nodemask) {
  69 @@ -2164,7 +2165,7 @@ static bool shrink_zones(int priority, s
  70                                  * allocations.
  71                                  */
  72                                 if (compaction_ready(zone, sc)) {
  73 -                                       should_abort_reclaim = true;
  74 +                                       aborted_reclaim = true;
  75                                         continue;
  76                                 }
  77                         }
  78 @@ -2186,7 +2187,7 @@ static bool shrink_zones(int priority, s
  79                 shrink_zone(priority, zone, sc);
  80         }
  81
  82 -       return should_abort_reclaim;
  83 +       return aborted_reclaim;
  84  }
  85
  86  static bool zone_reclaimable(struct zone *zone)
  87 @@ -2240,7 +2241,7 @@ static unsigned long do_try_to_free_page
  88         struct zoneref *z;
  89         struct zone *zone;
  90         unsigned long writeback_threshold;
  91 -       bool should_abort_reclaim;
  92 +       bool aborted_reclaim;
  93
  94         get_mems_allowed();
  95         delayacct_freepages_start();
  96 @@ -2252,9 +2253,7 @@ static unsigned long do_try_to_free_page
  97                 sc->nr_scanned = 0;
  98                 if (!priority)
  99                         disable_swap_token(sc->mem_cgroup);
 100 -               should_abort_reclaim = shrink_zones(priority, zonelist, sc);
 101 -               if (should_abort_reclaim)
 102 -                       break;
 103 +               aborted_reclaim = shrink_zones(priority, zonelist, sc);
 104
 105                 /*
 106                  * Don't shrink slabs when reclaiming memory from
 107 @@ -2320,8 +2319,8 @@ out:
 108         if (oom_killer_disabled)
 109                 return 0;
 110
 111 -       /* Aborting reclaim to try compaction? don't OOM, then */
 112 -       if (should_abort_reclaim)
 113 +       /* Aborted reclaim to try compaction? don't OOM, then */
 114 +       if (aborted_reclaim)
 115                 return 1;
 116
 117         /* top priority shrink_zones still had more to do? don't OOM, then */