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| author | Mel Gorman <mgorman@techsingularity.net> | 2016-07-28 15:47:31 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-28 16:07:41 -0700 |
| commit | 5a1c84b404a7176b8b36e2a0041b6f0adb3151a3 (patch) | |
| tree | ff98e242c5d4d3a24ca49f6ddc707028aeb938f9 /mm/compaction.c | |
| parent | bb4cc2bea6df7854d629bff114ca03237cc718d6 (diff) | |
| download | lwn-5a1c84b404a7176b8b36e2a0041b6f0adb3151a3.tar.gz lwn-5a1c84b404a7176b8b36e2a0041b6f0adb3151a3.zip | |
mm: remove reclaim and compaction retry approximations
If per-zone LRU accounting is available then there is no point
approximating whether reclaim and compaction should retry based on pgdat
statistics. This is effectively a revert of "mm, vmstat: remove zone
and node double accounting by approximating retries" with the difference
that inactive/active stats are still available. This preserves the
history of why the approximation was retried and why it had to be
reverted to handle OOM kills on 32-bit systems.
Link: http://lkml.kernel.org/r/1469110261-7365-4-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/compaction.c')
| -rw-r--r-- | mm/compaction.c | 20 |
1 files changed, 1 insertions, 19 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index cd93ea24c565..e5995f38d677 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1438,11 +1438,6 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order, { struct zone *zone; struct zoneref *z; - pg_data_t *last_pgdat = NULL; - - /* Do not retry compaction for zone-constrained allocations */ - if (ac->high_zoneidx < ZONE_NORMAL) - return false; /* * Make sure at least one zone would pass __compaction_suitable if we continue @@ -1453,27 +1448,14 @@ bool compaction_zonelist_suitable(struct alloc_context *ac, int order, unsigned long available; enum compact_result compact_result; - if (last_pgdat == zone->zone_pgdat) - continue; - - /* - * This over-estimates the number of pages available for - * reclaim/compaction but walking the LRU would take too - * long. The consequences are that compaction may retry - * longer than it should for a zone-constrained allocation - * request. - */ - last_pgdat = zone->zone_pgdat; - available = pgdat_reclaimable_pages(zone->zone_pgdat) / order; - /* * Do not consider all the reclaimable memory because we do not * want to trash just for a single high order allocation which * is even not guaranteed to appear even if __compaction_suitable * is happy about the watermark check. */ + available = zone_reclaimable_pages(zone) / order; available += zone_page_state_snapshot(zone, NR_FREE_PAGES); - available = min(zone->managed_pages, available); compact_result = __compaction_suitable(zone, order, alloc_flags, ac_classzone_idx(ac), available); if (compact_result != COMPACT_SKIPPED && |