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Commit bc835011 authored by Andrea Arcangeli's avatar Andrea Arcangeli Committed by Linus Torvalds
Browse files

thp: transhuge isolate_migratepages() 



It's not worth migrating transparent hugepages during compaction.  Those
hugepages don't create fragmentation.

Signed-off-by: default avatarAndrea Arcangeli <aarcange@redhat.com>
Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5d689240

mm/compaction.c

+15 −0
Original line number Diff line number Diff line
@@ -295,10 +295,25 @@ static unsigned long isolate_migratepages(struct zone *zone, 
			continue;

		}



		if (!PageLRU(page))

			continue;



		/*

		 * PageLRU is set, and lru_lock excludes isolation,

		 * splitting and collapsing (collapsing has already

		 * happened if PageLRU is set).

		 */

		if (PageTransHuge(page)) {

			low_pfn += (1 << compound_order(page)) - 1;

			continue;

		}



		/* Try isolate the page */

		if (__isolate_lru_page(page, ISOLATE_BOTH, 0) != 0)

			continue;



		VM_BUG_ON(PageTransCompound(page));



		/* Successfully isolated */

		del_page_from_lru_list(zone, page, page_lru(page));

		list_add(&page->lru, migratelist);