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@xxxxxxx> Acked-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>