Commit 2344d7e4 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
Browse files

mm: vmscan: remove all_unreclaimable() 



Direct reclaim currently calls shrink_zones() to reclaim all members of
a zonelist, and if that wasn't successful it does another pass through
the same zonelist to check overall reclaimability.

Just check reclaimability in shrink_zones() directly and propagate the
result through the return value.  Then remove all_unreclaimable().

Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0b06496a

mm/vmscan.c

+24 −25
Original line number Diff line number Diff line
@@ -2244,9 +2244,10 @@ static inline bool should_continue_reclaim(struct zone *zone, 
	}

}



static void shrink_zone(struct zone *zone, struct scan_control *sc)

static bool shrink_zone(struct zone *zone, struct scan_control *sc)

{

	unsigned long nr_reclaimed, nr_scanned;

	bool reclaimable = false;



	do {

		struct mem_cgroup *root = sc->target_mem_cgroup;
@@ -2290,8 +2291,13 @@ static void shrink_zone(struct zone *zone, struct scan_control *sc) 
			   sc->nr_scanned - nr_scanned,

			   sc->nr_reclaimed - nr_reclaimed);



		if (sc->nr_reclaimed - nr_reclaimed)

			reclaimable = true;



	} while (should_continue_reclaim(zone, sc->nr_reclaimed - nr_reclaimed,

					 sc->nr_scanned - nr_scanned, sc));



	return reclaimable;

}



/* Returns true if compaction should go ahead for a high-order request */
@@ -2340,8 +2346,10 @@ static inline bool compaction_ready(struct zone *zone, int order) 
 *

 * If a zone is deemed to be full of pinned pages then just give it a light

 * scan then give up on it.

 *

 * Returns true if a zone was reclaimable.

 */

static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc)

static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)

{

	struct zoneref *z;

	struct zone *zone;
@@ -2354,6 +2362,7 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) 
		.gfp_mask = sc->gfp_mask,

	};

	enum zone_type requested_highidx = gfp_zone(sc->gfp_mask);

	bool reclaimable = false;



	/*

	 * If the number of buffer_heads in the machine exceeds the maximum
@@ -2414,10 +2423,17 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) 
						&nr_soft_scanned);

			sc->nr_reclaimed += nr_soft_reclaimed;

			sc->nr_scanned += nr_soft_scanned;

			if (nr_soft_reclaimed)

				reclaimable = true;

			/* need some check for avoid more shrink_zone() */

		}



		shrink_zone(zone, sc);

		if (shrink_zone(zone, sc))

			reclaimable = true;



		if (global_reclaim(sc) &&

		    !reclaimable && zone_reclaimable(zone))

			reclaimable = true;

	}



	/*
@@ -2439,26 +2455,8 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) 
	 * promoted it to __GFP_HIGHMEM.

	 */

	sc->gfp_mask = orig_mask;

}



/* All zones in zonelist are unreclaimable? */

static bool all_unreclaimable(struct zonelist *zonelist,

		struct scan_control *sc)

{

	struct zoneref *z;

	struct zone *zone;



	for_each_zone_zonelist_nodemask(zone, z, zonelist,

			gfp_zone(sc->gfp_mask), sc->nodemask) {

		if (!populated_zone(zone))

			continue;

		if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))

			continue;

		if (zone_reclaimable(zone))

			return false;

	}



	return true;

	return reclaimable;

}



/*
@@ -2482,6 +2480,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, 
{

	unsigned long total_scanned = 0;

	unsigned long writeback_threshold;

	bool zones_reclaimable;



	delayacct_freepages_start();
@@ -2492,7 +2491,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, 
		vmpressure_prio(sc->gfp_mask, sc->target_mem_cgroup,

				sc->priority);

		sc->nr_scanned = 0;

		shrink_zones(zonelist, sc);

		zones_reclaimable = shrink_zones(zonelist, sc);



		total_scanned += sc->nr_scanned;

		if (sc->nr_reclaimed >= sc->nr_to_reclaim)
@@ -2532,8 +2531,8 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, 
	if (sc->compaction_ready)

		return 1;



	/* top priority shrink_zones still had more to do? don't OOM, then */

	if (global_reclaim(sc) && !all_unreclaimable(zonelist, sc))

	/* Any of the zones still reclaimable?  Don't OOM. */

	if (zones_reclaimable)

		return 1;



	return 0;

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