Commit de6c60a6 authored by Vlastimil Babka's avatar Vlastimil Babka Committed by Linus Torvalds
Browse files

mm: compaction: encapsulate defer reset logic 



Currently there are several functions to manipulate the deferred
compaction state variables.  The remaining case where the variables are
touched directly is when a successful allocation occurs in direct
compaction, or is expected to be successful in the future by kswapd.
Here, the lowest order that is expected to fail is updated, and in the
case of successful allocation, the deferred status and counter is reset
completely.

Create a new function compaction_defer_reset() to encapsulate this
functionality and make it easier to understand the code.  No functional
change.

Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
Acked-by: default avatarMel Gorman <mgorman@suse.de>
Reviewed-by: default avatarRik van Riel <riel@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0eb927c0

include/linux/compaction.h

+16 −0
Original line number Diff line number Diff line
@@ -62,6 +62,22 @@ static inline bool compaction_deferred(struct zone *zone, int order) 
	return zone->compact_considered < defer_limit;

}



/*

 * Update defer tracking counters after successful compaction of given order,

 * which means an allocation either succeeded (alloc_success == true) or is

 * expected to succeed.

 */

static inline void compaction_defer_reset(struct zone *zone, int order,

		bool alloc_success)

{

	if (alloc_success) {

		zone->compact_considered = 0;

		zone->compact_defer_shift = 0;

	}

	if (order >= zone->compact_order_failed)

		zone->compact_order_failed = order + 1;

}



/* Returns true if restarting compaction after many failures */

static inline bool compaction_restarting(struct zone *zone, int order)

{

mm/compaction.c

+4 −5
Original line number Diff line number Diff line
@@ -1124,12 +1124,11 @@ static void __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc) 
			compact_zone(zone, cc);



		if (cc->order > 0) {

			int ok = zone_watermark_ok(zone, cc->order,

						low_wmark_pages(zone), 0, 0);

			if (ok && cc->order >= zone->compact_order_failed)

				zone->compact_order_failed = cc->order + 1;

			if (zone_watermark_ok(zone, cc->order,

						low_wmark_pages(zone), 0, 0))

				compaction_defer_reset(zone, cc->order, false);

			/* Currently async compaction is never deferred. */

			else if (!ok && cc->sync)

			else if (cc->sync)

				defer_compaction(zone, cc->order);

		}

mm/page_alloc.c

+1 −4
Original line number Diff line number Diff line
@@ -2235,10 +2235,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, 
				preferred_zone, migratetype);

		if (page) {

			preferred_zone->compact_blockskip_flush = false;

			preferred_zone->compact_considered = 0;

			preferred_zone->compact_defer_shift = 0;

			if (order >= preferred_zone->compact_order_failed)

				preferred_zone->compact_order_failed = order + 1;

			compaction_defer_reset(preferred_zone, order, true);

			count_vm_event(COMPACTSUCCESS);

			return page;

		}

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