Commit aa02d3c1 authored by Yajun Deng's avatar Yajun Deng Committed by Andrew Morton
Browse files

mm/page_alloc: reduce fallbacks to (MIGRATE_PCPTYPES - 1) 

The commit 1dd214b8 ("mm: page_alloc: avoid merging non-fallbackable
pageblocks with others") has removed MIGRATE_CMA and MIGRATE_ISOLATE from
fallbacks list. so there is no need to add an element at the end of every
type.

Reduce fallbacks to (MIGRATE_PCPTYPES - 1).

Link: https://lkml.kernel.org/r/20230203100132.1627787-1-yajun.deng@linux.dev


Signed-off-by: default avatarYajun Deng <yajun.deng@linux.dev>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 601c3c29

mm/page_alloc.c

+5 −8
Original line number Diff line number Diff line
@@ -2603,10 +2603,10 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, 
 *

 * The other migratetypes do not have fallbacks.

 */

static int fallbacks[MIGRATE_TYPES][3] = {

	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_TYPES },

	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },

	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_TYPES },

static int fallbacks[MIGRATE_TYPES][MIGRATE_PCPTYPES - 1] = {

	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE   },

	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE },

	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE   },

};



#ifdef CONFIG_CMA
@@ -2865,11 +2865,8 @@ int find_suitable_fallback(struct free_area *area, unsigned int order, 
		return -1;



	*can_steal = false;

	for (i = 0;; i++) {

	for (i = 0; i < MIGRATE_PCPTYPES - 1 ; i++) {

		fallback_mt = fallbacks[migratetype][i];

		if (fallback_mt == MIGRATE_TYPES)

			break;



		if (free_area_empty(area, fallback_mt))

			continue;