Commit ebddd111 authored by Miaohe Lin's avatar Miaohe Lin Committed by Andrew Morton
Browse files

mm/page_alloc: avoid unneeded alike_pages calculation 

When free_pages is 0, alike_pages is not used.  So alike_pages calculation
can be avoided by checking free_pages early to save cpu cycles.  Also fix
typo 'comparable'.  It should be 'compatible' here.

Link: https://lkml.kernel.org/r/20230801123723.2225543-1-linmiaohe@huawei.com


Signed-off-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 549f5c77

mm/page_alloc.c

+5 −6
Original line number Diff line number Diff line
@@ -1833,6 +1833,10 @@ static void steal_suitable_fallback(struct zone *zone, struct page *page, 


	free_pages = move_freepages_block(zone, page, start_type,

						&movable_pages);

	/* moving whole block can fail due to zone boundary conditions */

	if (!free_pages)

		goto single_page;



	/*

	 * Determine how many pages are compatible with our allocation.

	 * For movable allocation, it's the number of movable pages which
@@ -1854,14 +1858,9 @@ static void steal_suitable_fallback(struct zone *zone, struct page *page, 
		else

			alike_pages = 0;

	}



	/* moving whole block can fail due to zone boundary conditions */

	if (!free_pages)

		goto single_page;



	/*

	 * If a sufficient number of pages in the block are either free or of

	 * comparable migratability as our allocation, claim the whole block.

	 * compatible migratability as our allocation, claim the whole block.

	 */

	if (free_pages + alike_pages >= (1 << (pageblock_order-1)) ||

			page_group_by_mobility_disabled)