Commit fa599c44 authored by Miaohe Lin's avatar Miaohe Lin Committed by Andrew Morton
Browse files

mm: compaction: simplify the code in __compact_finished 

Since commit efe771c7 ("mm, compaction: always finish scanning of a
full pageblock"), compaction will always finish scanning a pageblock.  And
migrate_pfn is assured to align with pageblock_nr_pages when we reach
here.  So we will always return COMPACT_SUCCESS if a suitable fallback is
found due to the below IS_ALIGNED check of migrate_pfn.  Simplify the code
to make this clear and improve the readability.  No functional change
intended.

Link: https://lkml.kernel.org/r/20220418141253.24298-12-linmiaohe@huawei.com


Signed-off-by: default avatarMiaohe Lin <linmiaohe@huawei.com>
Cc: Charan Teja Kalla <charante@codeaurora.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Pintu Kumar <pintu@codeaurora.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent cff387d6

mm/compaction.c

+8 −21
Original line number Diff line number Diff line
@@ -2134,31 +2134,18 @@ static enum compact_result __compact_finished(struct compact_control *cc) 
		 * other migratetype buddy lists.

		 */

		if (find_suitable_fallback(area, order, migratetype,

						true, &can_steal) != -1) {



			/* movable pages are OK in any pageblock */

			if (migratetype == MIGRATE_MOVABLE)

				return COMPACT_SUCCESS;



						true, &can_steal) != -1)

			/*

			 * We are stealing for a non-movable allocation. Make

			 * sure we finish compacting the current pageblock

			 * first so it is as free as possible and we won't

			 * have to steal another one soon. This only applies

			 * to sync compaction, as async compaction operates

			 * on pageblocks of the same migratetype.

			 * Movable pages are OK in any pageblock. If we are

			 * stealing for a non-movable allocation, make sure

			 * we finish compacting the current pageblock first

			 * (which is assured by the above migrate_pfn align

			 * check) so it is as free as possible and we won't

			 * have to steal another one soon.

			 */

			if (cc->mode == MIGRATE_ASYNC ||

					IS_ALIGNED(cc->migrate_pfn,

							pageblock_nr_pages)) {

			return COMPACT_SUCCESS;

	}



			ret = COMPACT_CONTINUE;

			break;

		}

	}



out:

	if (cc->contended || fatal_signal_pending(current))

		ret = COMPACT_CONTENDED;