Messages in this thread | | | Date | Tue, 16 Jun 2015 14:45:06 +0900 | From | Joonsoo Kim <> | Subject | Re: [PATCH 5/6] mm, compaction: skip compound pages by order in free scanner |
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On Wed, Jun 10, 2015 at 11:32:33AM +0200, Vlastimil Babka wrote: > The compaction free scanner is looking for PageBuddy() pages and skipping all > others. For large compound pages such as THP or hugetlbfs, we can save a lot > of iterations if we skip them at once using their compound_order(). This is > generally unsafe and we can read a bogus value of order due to a race, but if > we are careful, the only danger is skipping too much. > > When tested with stress-highalloc from mmtests on 4GB system with 1GB hugetlbfs > pages, the vmstat compact_free_scanned count decreased by at least 15%. > > Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Thanks.
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