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author | 2012-01-12 17:19:49 -0800 | |
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committer | 2012-01-12 20:13:09 -0800 | |
commit | 0cee34fd72c582b4f8ad8ce00645b75fb4168199 (patch) | |
tree | 3b3bd79df0a2ebc869dba091d922c252784ffd23 /mm | |
parent | mm: vmscan: when reclaiming for compaction, ensure there are sufficient free ... (diff) | |
download | linux-0cee34fd72c582b4f8ad8ce00645b75fb4168199.tar.gz linux-0cee34fd72c582b4f8ad8ce00645b75fb4168199.tar.bz2 linux-0cee34fd72c582b4f8ad8ce00645b75fb4168199.zip |
mm: vmscan: check if reclaim should really abort even if compaction_ready() is true for one zone
If compaction can proceed for a given zone, shrink_zones() does not
reclaim any more pages from it. After commit [e0c2327: vmscan: abort
reclaim/compaction if compaction can proceed], do_try_to_free_pages()
tries to finish as soon as possible once one zone can compact.
This was intended to prevent slabs being shrunk unnecessarily but there
are side-effects. One is that a small zone that is ready for compaction
will abort reclaim even if the chances of successfully allocating a THP
from that zone is small. It also means that reclaim can return too early
even though sc->nr_to_reclaim pages were not reclaimed.
This partially reverts the commit until it is proven that slabs are really
being shrunk unnecessarily but preserves the check to return 1 to avoid
OOM if reclaim was aborted prematurely.
[aarcange@redhat.com: This patch replaces a revert from Andrea]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/vmscan.c | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 3b8ede882396..25f90383b391 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2217,7 +2217,8 @@ static inline bool compaction_ready(struct zone *zone, struct scan_control *sc) * * This function returns true if a zone is being reclaimed for a costly * high-order allocation and compaction is ready to begin. This indicates to - * the caller that it should retry the allocation or fail. + * the caller that it should consider retrying the allocation instead of + * further reclaim. */ static bool shrink_zones(int priority, struct zonelist *zonelist, struct scan_control *sc) @@ -2226,7 +2227,7 @@ static bool shrink_zones(int priority, struct zonelist *zonelist, struct zone *zone; unsigned long nr_soft_reclaimed; unsigned long nr_soft_scanned; - bool should_abort_reclaim = false; + bool aborted_reclaim = false; for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(sc->gfp_mask), sc->nodemask) { @@ -2252,7 +2253,7 @@ static bool shrink_zones(int priority, struct zonelist *zonelist, * allocations. */ if (compaction_ready(zone, sc)) { - should_abort_reclaim = true; + aborted_reclaim = true; continue; } } @@ -2274,7 +2275,7 @@ static bool shrink_zones(int priority, struct zonelist *zonelist, shrink_zone(priority, zone, sc); } - return should_abort_reclaim; + return aborted_reclaim; } static bool zone_reclaimable(struct zone *zone) @@ -2328,7 +2329,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, struct zoneref *z; struct zone *zone; unsigned long writeback_threshold; - bool should_abort_reclaim; + bool aborted_reclaim; get_mems_allowed(); delayacct_freepages_start(); @@ -2340,9 +2341,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, sc->nr_scanned = 0; if (!priority) disable_swap_token(sc->target_mem_cgroup); - should_abort_reclaim = shrink_zones(priority, zonelist, sc); - if (should_abort_reclaim) - break; + aborted_reclaim = shrink_zones(priority, zonelist, sc); /* * Don't shrink slabs when reclaiming memory from @@ -2409,8 +2408,8 @@ out: if (oom_killer_disabled) return 0; - /* Aborting reclaim to try compaction? don't OOM, then */ - if (should_abort_reclaim) + /* Aborted reclaim to try compaction? don't OOM, then */ + if (aborted_reclaim) return 1; /* top priority shrink_zones still had more to do? don't OOM, then */ |