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authorVlastimil Babka <vbabka@suse.cz>2014-06-04 16:08:34 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-04 16:54:07 -0700
commite9ade569910a82614ff5f2c2cea2b65a8d785da4 (patch)
tree0540262e4eb7d5316e219bd4ef6426649b30b4c4 /mm/vmstat.c
parentf8c9301fa5a2a8b873c67f2a3d8230d5c13f61b7 (diff)
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mm/compaction: avoid rescanning pageblocks in isolate_freepages
The compaction free scanner in isolate_freepages() currently remembers PFN of the highest pageblock where it successfully isolates, to be used as the starting pageblock for the next invocation. The rationale behind this is that page migration might return free pages to the allocator when migration fails and we don't want to skip them if the compaction continues. Since migration now returns free pages back to compaction code where they can be reused, this is no longer a concern. This patch changes isolate_freepages() so that the PFN for restarting is updated with each pageblock where isolation is attempted. Using stress-highalloc from mmtests, this resulted in 10% reduction of the pages scanned by the free scanner. Note that the somewhat similar functionality that records highest successful pageblock in zone->compact_cached_free_pfn, remains unchanged. This cache is used when the whole compaction is restarted, not for multiple invocations of the free scanner during single compaction. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmstat.c')
0 files changed, 0 insertions, 0 deletions
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