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>
This commit is contained in:
parent
fe4b1b244b
commit
0cee34fd72
19
mm/vmscan.c
19
mm/vmscan.c
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@ -2217,7 +2217,8 @@ static inline bool compaction_ready(struct zone *zone, struct scan_control *sc)
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*
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* This function returns true if a zone is being reclaimed for a costly
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* high-order allocation and compaction is ready to begin. This indicates to
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* the caller that it should retry the allocation or fail.
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* the caller that it should consider retrying the allocation instead of
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* further reclaim.
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*/
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static bool shrink_zones(int priority, struct zonelist *zonelist,
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struct scan_control *sc)
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@ -2226,7 +2227,7 @@ static bool shrink_zones(int priority, struct zonelist *zonelist,
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struct zone *zone;
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unsigned long nr_soft_reclaimed;
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unsigned long nr_soft_scanned;
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bool should_abort_reclaim = false;
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bool aborted_reclaim = false;
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for_each_zone_zonelist_nodemask(zone, z, zonelist,
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gfp_zone(sc->gfp_mask), sc->nodemask) {
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@ -2252,7 +2253,7 @@ static bool shrink_zones(int priority, struct zonelist *zonelist,
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* allocations.
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*/
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if (compaction_ready(zone, sc)) {
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should_abort_reclaim = true;
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aborted_reclaim = true;
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continue;
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}
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}
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@ -2274,7 +2275,7 @@ static bool shrink_zones(int priority, struct zonelist *zonelist,
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shrink_zone(priority, zone, sc);
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}
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return should_abort_reclaim;
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return aborted_reclaim;
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}
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static bool zone_reclaimable(struct zone *zone)
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@ -2328,7 +2329,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
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struct zoneref *z;
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struct zone *zone;
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unsigned long writeback_threshold;
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bool should_abort_reclaim;
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bool aborted_reclaim;
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get_mems_allowed();
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delayacct_freepages_start();
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@ -2340,9 +2341,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
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sc->nr_scanned = 0;
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if (!priority)
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disable_swap_token(sc->target_mem_cgroup);
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should_abort_reclaim = shrink_zones(priority, zonelist, sc);
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if (should_abort_reclaim)
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break;
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aborted_reclaim = shrink_zones(priority, zonelist, sc);
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/*
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* Don't shrink slabs when reclaiming memory from
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@ -2409,8 +2408,8 @@ out:
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if (oom_killer_disabled)
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return 0;
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/* Aborting reclaim to try compaction? don't OOM, then */
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if (should_abort_reclaim)
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/* Aborted reclaim to try compaction? don't OOM, then */
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if (aborted_reclaim)
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return 1;
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/* top priority shrink_zones still had more to do? don't OOM, then */
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