Commit c8f7de0b authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
Browse files

mm, compaction: distinguish between full and partial COMPACT_COMPLETE 



COMPACT_COMPLETE now means that compaction and free scanner met.  This
is not very useful information if somebody just wants to use this
feedback and make any decisions based on that.  The current caller might
be a poor guy who just happened to scan tiny portion of the zone and
that could be the reason no suitable pages were compacted.  Make sure we
distinguish the full and partial zone walks.

Consumers should treat COMPACT_PARTIAL_SKIPPED as a potential success
and be optimistic in retrying.

The existing users of COMPACT_COMPLETE are conservatively changed to use
COMPACT_PARTIAL_SKIPPED as well but some of them should be probably
reconsidered and only defer the compaction only for COMPACT_COMPLETE
with the new semantic.

This patch shouldn't introduce any functional changes.

Signed-off-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarVlastimil Babka <vbabka@suse.cz>
Acked-by: default avatarHillf Danton <hillf.zj@alibaba-inc.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1d4746d3

include/linux/compaction.h

+9 −1
Original line number Original line Diff line number Diff line
@@ -21,7 +21,15 @@ enum compact_result { 
	 * pages

	 * pages

	 */

	 */

	COMPACT_PARTIAL,

	COMPACT_PARTIAL,

	/* The full zone was compacted */

	/*

	 * direct compaction has scanned part of the zone but wasn't successfull

	 * to compact suitable pages.

	 */

	COMPACT_PARTIAL_SKIPPED,

	/*

	 * The full zone was compacted scanned but wasn't successfull to compact

	 * suitable pages.

	 */

	COMPACT_COMPLETE,

	COMPACT_COMPLETE,

	/* For more detailed tracepoint output */

	/* For more detailed tracepoint output */

	COMPACT_NO_SUITABLE_PAGE,

	COMPACT_NO_SUITABLE_PAGE,

include/trace/events/compaction.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -14,6 +14,7 @@ 
	EM( COMPACT_DEFERRED,		"deferred")		\

	EM( COMPACT_DEFERRED,		"deferred")		\

	EM( COMPACT_CONTINUE,		"continue")		\

	EM( COMPACT_CONTINUE,		"continue")		\

	EM( COMPACT_PARTIAL,		"partial")		\

	EM( COMPACT_PARTIAL,		"partial")		\

	EM( COMPACT_PARTIAL_SKIPPED,	"partial_skipped")	\

	EM( COMPACT_COMPLETE,		"complete")		\

	EM( COMPACT_COMPLETE,		"complete")		\

	EM( COMPACT_NO_SUITABLE_PAGE,	"no_suitable_page")	\

	EM( COMPACT_NO_SUITABLE_PAGE,	"no_suitable_page")	\

	EM( COMPACT_NOT_SUITABLE_ZONE,	"not_suitable_zone")	\

	EM( COMPACT_NOT_SUITABLE_ZONE,	"not_suitable_zone")	\

mm/compaction.c

+11 −3
Original line number Original line Diff line number Diff line
@@ -1252,7 +1252,10 @@ static enum compact_result __compact_finished(struct zone *zone, struct compact_ 
		if (cc->direct_compaction)

		if (cc->direct_compaction)

			zone->compact_blockskip_flush = true;

			zone->compact_blockskip_flush = true;





		if (cc->whole_zone)

			return COMPACT_COMPLETE;

			return COMPACT_COMPLETE;

		else

			return COMPACT_PARTIAL_SKIPPED;

	}

	}





	if (is_via_compact_memory(cc->order))

	if (is_via_compact_memory(cc->order))
@@ -1413,6 +1416,10 @@ static enum compact_result compact_zone(struct zone *zone, struct compact_contro 
		zone->compact_cached_migrate_pfn[0] = cc->migrate_pfn;

		zone->compact_cached_migrate_pfn[0] = cc->migrate_pfn;

		zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn;

		zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn;

	}

	}



	if (cc->migrate_pfn == start_pfn)

		cc->whole_zone = true;



	cc->last_migrated_pfn = 0;

	cc->last_migrated_pfn = 0;





	trace_mm_compaction_begin(start_pfn, cc->migrate_pfn,

	trace_mm_compaction_begin(start_pfn, cc->migrate_pfn,
@@ -1634,7 +1641,8 @@ enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, 
			goto break_loop;

			goto break_loop;

		}

		}





		if (mode != MIGRATE_ASYNC && status == COMPACT_COMPLETE) {

		if (mode != MIGRATE_ASYNC && (status == COMPACT_COMPLETE ||

					status == COMPACT_PARTIAL_SKIPPED)) {

			/*

			/*

			 * We think that allocation won't succeed in this zone

			 * We think that allocation won't succeed in this zone

			 * so we defer compaction there. If it ends up

			 * so we defer compaction there. If it ends up
@@ -1881,7 +1889,7 @@ static void kcompactd_do_work(pg_data_t *pgdat) 
						cc.classzone_idx, 0)) {

						cc.classzone_idx, 0)) {

			success = true;

			success = true;

			compaction_defer_reset(zone, cc.order, false);

			compaction_defer_reset(zone, cc.order, false);

		} else if (status == COMPACT_COMPLETE) {

		} else if (status == COMPACT_PARTIAL_SKIPPED || status == COMPACT_COMPLETE) {

			/*

			/*

			 * We use sync migration mode here, so we defer like

			 * We use sync migration mode here, so we defer like

			 * sync direct compaction does.

			 * sync direct compaction does.

mm/internal.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -174,6 +174,7 @@ struct compact_control { 
	enum migrate_mode mode;		/* Async or sync migration mode */

	enum migrate_mode mode;		/* Async or sync migration mode */

	bool ignore_skip_hint;		/* Scan blocks even if marked skip */

	bool ignore_skip_hint;		/* Scan blocks even if marked skip */

	bool direct_compaction;		/* False from kcompactd or /proc/... */

	bool direct_compaction;		/* False from kcompactd or /proc/... */

	bool whole_zone;		/* Whole zone has been scanned */

	int order;			/* order a direct compactor needs */

	int order;			/* order a direct compactor needs */

	const gfp_t gfp_mask;		/* gfp mask of a direct compactor */

	const gfp_t gfp_mask;		/* gfp mask of a direct compactor */

	const unsigned int alloc_flags;	/* alloc flags of a direct compactor */

	const unsigned int alloc_flags;	/* alloc flags of a direct compactor */

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