Commit cf378319 authored by Vlastimil Babka's avatar Vlastimil Babka Committed by Linus Torvalds
Browse files

mm, compaction: rename COMPACT_PARTIAL to COMPACT_SUCCESS 

COMPACT_PARTIAL has historically meant that compaction returned after
doing some work without fully compacting a zone.  It however didn't
distinguish if compaction terminated because it succeeded in creating
the requested high-order page.  This has changed recently and now we
only return COMPACT_PARTIAL when compaction thinks it succeeded, or the
high-order watermark check in compaction_suitable() passes and no
compaction needs to be done.

So at this point we can make the return value clearer by renaming it to
COMPACT_SUCCESS.  The next patch will remove some redundant tests for
success where compaction just returned COMPACT_SUCCESS.

Link: http://lkml.kernel.org/r/20160810091226.6709-4-vbabka@suse.cz


Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
Tested-by: default avatarLorenzo Stoakes <lstoakes@gmail.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 791cae96

include/linux/compaction.h

+4 −4
Original line number Diff line number Diff line
@@ -49,10 +49,10 @@ enum compact_result { 
	COMPACT_CONTENDED,



	/*

	 * direct compaction partially compacted a zone and there might be

	 * suitable pages

	 * direct compaction terminated after concluding that the allocation

	 * should now succeed

	 */

	COMPACT_PARTIAL,

	COMPACT_SUCCESS,

};



struct alloc_context; /* in mm/internal.h */
@@ -88,7 +88,7 @@ static inline bool compaction_made_progress(enum compact_result result) 
	 * that the compaction successfully isolated and migrated some

	 * pageblocks.

	 */

	if (result == COMPACT_PARTIAL)

	if (result == COMPACT_SUCCESS)

		return true;



	return false;

include/trace/events/compaction.h

+1 −1
Original line number Diff line number Diff line
@@ -13,7 +13,7 @@ 
	EM( COMPACT_SKIPPED,		"skipped")		\

	EM( COMPACT_DEFERRED,		"deferred")		\

	EM( COMPACT_CONTINUE,		"continue")		\

	EM( COMPACT_PARTIAL,		"partial")		\

	EM( COMPACT_SUCCESS,		"success")		\

	EM( COMPACT_PARTIAL_SKIPPED,	"partial_skipped")	\

	EM( COMPACT_COMPLETE,		"complete")		\

	EM( COMPACT_NO_SUITABLE_PAGE,	"no_suitable_page")	\

mm/compaction.c

+6 −6
Original line number Diff line number Diff line
@@ -1329,13 +1329,13 @@ static enum compact_result __compact_finished(struct zone *zone, struct compact_ 


		/* Job done if page is free of the right migratetype */

		if (!list_empty(&area->free_list[migratetype]))

			return COMPACT_PARTIAL;

			return COMPACT_SUCCESS;



#ifdef CONFIG_CMA

		/* MIGRATE_MOVABLE can fallback on MIGRATE_CMA */

		if (migratetype == MIGRATE_MOVABLE &&

			!list_empty(&area->free_list[MIGRATE_CMA]))

			return COMPACT_PARTIAL;

			return COMPACT_SUCCESS;

#endif

		/*

		 * Job done if allocation would steal freepages from
@@ -1343,7 +1343,7 @@ static enum compact_result __compact_finished(struct zone *zone, struct compact_ 
		 */

		if (find_suitable_fallback(area, order, migratetype,

						true, &can_steal) != -1)

			return COMPACT_PARTIAL;

			return COMPACT_SUCCESS;

	}



	return COMPACT_NO_SUITABLE_PAGE;
@@ -1367,7 +1367,7 @@ static enum compact_result compact_finished(struct zone *zone, 
 * compaction_suitable: Is this suitable to run compaction on this zone now?

 * Returns

 *   COMPACT_SKIPPED  - If there are too few free pages for compaction

 *   COMPACT_PARTIAL  - If the allocation would succeed without compaction

 *   COMPACT_SUCCESS  - If the allocation would succeed without compaction

 *   COMPACT_CONTINUE - If compaction should run now

 */

static enum compact_result __compaction_suitable(struct zone *zone, int order,
@@ -1388,7 +1388,7 @@ static enum compact_result __compaction_suitable(struct zone *zone, int order, 
	 */

	if (zone_watermark_ok(zone, order, watermark, classzone_idx,

								alloc_flags))

		return COMPACT_PARTIAL;

		return COMPACT_SUCCESS;



	/*

	 * Watermarks for order-0 must be met for compaction. Note the 2UL.
@@ -1477,7 +1477,7 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro 
	ret = compaction_suitable(zone, cc->order, cc->alloc_flags,

							cc->classzone_idx);

	/* Compaction is likely to fail */

	if (ret == COMPACT_PARTIAL || ret == COMPACT_SKIPPED)

	if (ret == COMPACT_SUCCESS || ret == COMPACT_SKIPPED)

		return ret;



	/* huh, compaction_suitable is returning something unexpected */

mm/vmscan.c

+1 −1
Original line number Diff line number Diff line
@@ -2495,7 +2495,7 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat, 
			continue;



		switch (compaction_suitable(zone, sc->order, 0, sc->reclaim_idx)) {

		case COMPACT_PARTIAL:

		case COMPACT_SUCCESS:

		case COMPACT_CONTINUE:

			return false;

		default:

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