1 files changed, 90 insertions, 126 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index a384339bf718..bd9a72bc4a1b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -229,9 +229,10 @@ EXPORT_SYMBOL(unregister_shrinker);
 
 #define SHRINK_BATCH 128
 
-static unsigned long
-shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
-		 unsigned long nr_pages_scanned, unsigned long lru_pages)
+static unsigned long shrink_slabs(struct shrink_control *shrinkctl,
+				  struct shrinker *shrinker,
+				  unsigned long nr_scanned,
+				  unsigned long nr_eligible)
 {
 	unsigned long freed = 0;
 	unsigned long long delta;
@@ -255,9 +256,9 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
 	nr = atomic_long_xchg(&shrinker->nr_deferred[nid], 0);
 
 	total_scan = nr;
-	delta = (4 * nr_pages_scanned) / shrinker->seeks;
+	delta = (4 * nr_scanned) / shrinker->seeks;
 	delta *= freeable;
-	do_div(delta, lru_pages + 1);
+	do_div(delta, nr_eligible + 1);
 	total_scan += delta;
 	if (total_scan < 0) {
 		pr_err("shrink_slab: %pF negative objects to delete nr=%ld\n",
@@ -289,8 +290,8 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
 		total_scan = freeable * 2;
 
 	trace_mm_shrink_slab_start(shrinker, shrinkctl, nr,
-				nr_pages_scanned, lru_pages,
-				freeable, delta, total_scan);
+				   nr_scanned, nr_eligible,
+				   freeable, delta, total_scan);
 
 	/*
 	 * Normally, we should not scan less than batch_size objects in one
@@ -339,34 +340,37 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
 	return freed;
 }
 
-/*
- * Call the shrink functions to age shrinkable caches
- *
- * Here we assume it costs one seek to replace a lru page and that it also
- * takes a seek to recreate a cache object.  With this in mind we age equal
- * percentages of the lru and ageable caches.  This should balance the seeks
- * generated by these structures.
+/**
+ * shrink_node_slabs - shrink slab caches of a given node
+ * @gfp_mask: allocation context
+ * @nid: node whose slab caches to target
+ * @nr_scanned: pressure numerator
+ * @nr_eligible: pressure denominator
  *
- * If the vm encountered mapped pages on the LRU it increase the pressure on
- * slab to avoid swapping.
+ * Call the shrink functions to age shrinkable caches.
  *
- * We do weird things to avoid (scanned*seeks*entries) overflowing 32 bits.
+ * @nid is passed along to shrinkers with SHRINKER_NUMA_AWARE set,
+ * unaware shrinkers will receive a node id of 0 instead.
  *
- * `lru_pages' represents the number of on-LRU pages in all the zones which
- * are eligible for the caller's allocation attempt.  It is used for balancing
- * slab reclaim versus page reclaim.
+ * @nr_scanned and @nr_eligible form a ratio that indicate how much of
+ * the available objects should be scanned.  Page reclaim for example
+ * passes the number of pages scanned and the number of pages on the
+ * LRU lists that it considered on @nid, plus a bias in @nr_scanned
+ * when it encountered mapped pages.  The ratio is further biased by
+ * the ->seeks setting of the shrink function, which indicates the
+ * cost to recreate an object relative to that of an LRU page.
  *
- * Returns the number of slab objects which we shrunk.
+ * Returns the number of reclaimed slab objects.
  */
-unsigned long shrink_slab(struct shrink_control *shrinkctl,
-			  unsigned long nr_pages_scanned,
-			  unsigned long lru_pages)
+unsigned long shrink_node_slabs(gfp_t gfp_mask, int nid,
+				unsigned long nr_scanned,
+				unsigned long nr_eligible)
 {
 	struct shrinker *shrinker;
 	unsigned long freed = 0;
 
-	if (nr_pages_scanned == 0)
-		nr_pages_scanned = SWAP_CLUSTER_MAX;
+	if (nr_scanned == 0)
+		nr_scanned = SWAP_CLUSTER_MAX;
 
 	if (!down_read_trylock(&shrinker_rwsem)) {
 		/*
@@ -380,20 +384,17 @@ unsigned long shrink_slab(struct shrink_control *shrinkctl,
 	}
 
 	list_for_each_entry(shrinker, &shrinker_list, list) {
-		if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) {
-			shrinkctl->nid = 0;
-			freed += shrink_slab_node(shrinkctl, shrinker,
-					nr_pages_scanned, lru_pages);
-			continue;
-		}
+		struct shrink_control sc = {
+			.gfp_mask = gfp_mask,
+			.nid = nid,
+		};
 
-		for_each_node_mask(shrinkctl->nid, shrinkctl->nodes_to_scan) {
-			if (node_online(shrinkctl->nid))
-				freed += shrink_slab_node(shrinkctl, shrinker,
-						nr_pages_scanned, lru_pages);
+		if (!(shrinker->flags & SHRINKER_NUMA_AWARE))
+			sc.nid = 0;
 
-		}
+		freed += shrink_slabs(&sc, shrinker, nr_scanned, nr_eligible);
 	}
+
 	up_read(&shrinker_rwsem);
 out:
 	cond_resched();
@@ -1876,7 +1877,8 @@ enum scan_balance {
  * nr[2] = file inactive pages to scan; nr[3] = file active pages to scan
  */
 static void get_scan_count(struct lruvec *lruvec, int swappiness,
-			   struct scan_control *sc, unsigned long *nr)
+			   struct scan_control *sc, unsigned long *nr,
+			   unsigned long *lru_pages)
 {
 	struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
 	u64 fraction[2];
@@ -2022,6 +2024,7 @@ out:
 	some_scanned = false;
 	/* Only use force_scan on second pass. */
 	for (pass = 0; !some_scanned && pass < 2; pass++) {
+		*lru_pages = 0;
 		for_each_evictable_lru(lru) {
 			int file = is_file_lru(lru);
 			unsigned long size;
@@ -2048,14 +2051,19 @@ out:
 			case SCAN_FILE:
 			case SCAN_ANON:
 				/* Scan one type exclusively */
-				if ((scan_balance == SCAN_FILE) != file)
+				if ((scan_balance == SCAN_FILE) != file) {
+					size = 0;
 					scan = 0;
+				}
 				break;
 			default:
 				/* Look ma, no brain */
 				BUG();
 			}
+
+			*lru_pages += size;
 			nr[lru] = scan;
+
 			/*
 			 * Skip the second pass and don't force_scan,
 			 * if we found something to scan.
@@ -2069,7 +2077,7 @@ out:
  * This is a basic per-zone page freer.  Used by both kswapd and direct reclaim.
  */
 static void shrink_lruvec(struct lruvec *lruvec, int swappiness,
-			  struct scan_control *sc)
+			  struct scan_control *sc, unsigned long *lru_pages)
 {
 	unsigned long nr[NR_LRU_LISTS];
 	unsigned long targets[NR_LRU_LISTS];
@@ -2080,7 +2088,7 @@ static void shrink_lruvec(struct lruvec *lruvec, int swappiness,
 	struct blk_plug plug;
 	bool scan_adjusted;
 
-	get_scan_count(lruvec, swappiness, sc, nr);
+	get_scan_count(lruvec, swappiness, sc, nr, lru_pages);
 
 	/* Record the original scan target for proportional adjustments later */
 	memcpy(targets, nr, sizeof(nr));
@@ -2258,7 +2266,8 @@ static inline bool should_continue_reclaim(struct zone *zone,
 	}
 }
 
-static bool shrink_zone(struct zone *zone, struct scan_control *sc)
+static bool shrink_zone(struct zone *zone, struct scan_control *sc,
+			bool is_classzone)
 {
 	unsigned long nr_reclaimed, nr_scanned;
 	bool reclaimable = false;
@@ -2269,6 +2278,7 @@ static bool shrink_zone(struct zone *zone, struct scan_control *sc)
 			.zone = zone,
 			.priority = sc->priority,
 		};
+		unsigned long zone_lru_pages = 0;
 		struct mem_cgroup *memcg;
 
 		nr_reclaimed = sc->nr_reclaimed;
@@ -2276,13 +2286,15 @@ static bool shrink_zone(struct zone *zone, struct scan_control *sc)
 
 		memcg = mem_cgroup_iter(root, NULL, &reclaim);
 		do {
+			unsigned long lru_pages;
 			struct lruvec *lruvec;
 			int swappiness;
 
 			lruvec = mem_cgroup_zone_lruvec(zone, memcg);
 			swappiness = mem_cgroup_swappiness(memcg);
 
-			shrink_lruvec(lruvec, swappiness, sc);
+			shrink_lruvec(lruvec, swappiness, sc, &lru_pages);
+			zone_lru_pages += lru_pages;
 
 			/*
 			 * Direct reclaim and kswapd have to scan all memory
@@ -2302,6 +2314,25 @@ static bool shrink_zone(struct zone *zone, struct scan_control *sc)
 			memcg = mem_cgroup_iter(root, memcg, &reclaim);
 		} while (memcg);
 
+		/*
+		 * Shrink the slab caches in the same proportion that
+		 * the eligible LRU pages were scanned.
+		 */
+		if (global_reclaim(sc) && is_classzone) {
+			struct reclaim_state *reclaim_state;
+
+			shrink_node_slabs(sc->gfp_mask, zone_to_nid(zone),
+					  sc->nr_scanned - nr_scanned,
+					  zone_lru_pages);
+
+			reclaim_state = current->reclaim_state;
+			if (reclaim_state) {
+				sc->nr_reclaimed +=
+					reclaim_state->reclaimed_slab;
+				reclaim_state->reclaimed_slab = 0;
+			}
+		}
+
 		vmpressure(sc->gfp_mask, sc->target_mem_cgroup,
 			   sc->nr_scanned - nr_scanned,
 			   sc->nr_reclaimed - nr_reclaimed);
@@ -2376,12 +2407,7 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 	struct zone *zone;
 	unsigned long nr_soft_reclaimed;
 	unsigned long nr_soft_scanned;
-	unsigned long lru_pages = 0;
-	struct reclaim_state *reclaim_state = current->reclaim_state;
 	gfp_t orig_mask;
-	struct shrink_control shrink = {
-		.gfp_mask = sc->gfp_mask,
-	};
 	enum zone_type requested_highidx = gfp_zone(sc->gfp_mask);
 	bool reclaimable = false;
 
@@ -2394,12 +2420,18 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 	if (buffer_heads_over_limit)
 		sc->gfp_mask |= __GFP_HIGHMEM;
 
-	nodes_clear(shrink.nodes_to_scan);
-
 	for_each_zone_zonelist_nodemask(zone, z, zonelist,
-					gfp_zone(sc->gfp_mask), sc->nodemask) {
+					requested_highidx, sc->nodemask) {
+		enum zone_type classzone_idx;
+
 		if (!populated_zone(zone))
 			continue;
+
+		classzone_idx = requested_highidx;
+		while (!populated_zone(zone->zone_pgdat->node_zones +
+							classzone_idx))
+			classzone_idx--;
+
 		/*
 		 * Take care memory controller reclaiming has small influence
 		 * to global LRU.
@@ -2409,9 +2441,6 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 						 GFP_KERNEL | __GFP_HARDWALL))
 				continue;
 
-			lru_pages += zone_reclaimable_pages(zone);
-			node_set(zone_to_nid(zone), shrink.nodes_to_scan);
-
 			if (sc->priority != DEF_PRIORITY &&
 			    !zone_reclaimable(zone))
 				continue;	/* Let kswapd poll it */
@@ -2450,7 +2479,7 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 			/* need some check for avoid more shrink_zone() */
 		}
 
-		if (shrink_zone(zone, sc))
+		if (shrink_zone(zone, sc, zone_idx(zone) == classzone_idx))
 			reclaimable = true;
 
 		if (global_reclaim(sc) &&
@@ -2459,20 +2488,6 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 	}
 
 	/*
-	 * Don't shrink slabs when reclaiming memory from over limit cgroups
-	 * but do shrink slab at least once when aborting reclaim for
-	 * compaction to avoid unevenly scanning file/anon LRU pages over slab
-	 * pages.
-	 */
-	if (global_reclaim(sc)) {
-		shrink_slab(&shrink, sc->nr_scanned, lru_pages);
-		if (reclaim_state) {
-			sc->nr_reclaimed += reclaim_state->reclaimed_slab;
-			reclaim_state->reclaimed_slab = 0;
-		}
-	}
-
-	/*
 	 * Restore to original mask to avoid the impact on the caller if we
 	 * promoted it to __GFP_HIGHMEM.
 	 */
@@ -2736,6 +2751,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
 	};
 	struct lruvec *lruvec = mem_cgroup_zone_lruvec(zone, memcg);
 	int swappiness = mem_cgroup_swappiness(memcg);
+	unsigned long lru_pages;
 
 	sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
 			(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
@@ -2751,7 +2767,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *memcg,
 	 * will pick up pages from other mem cgroup's as well. We hack
 	 * the priority and make it zero.
 	 */
-	shrink_lruvec(lruvec, swappiness, &sc);
+	shrink_lruvec(lruvec, swappiness, &sc, &lru_pages);
 
 	trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);
 
@@ -2932,15 +2948,10 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining,
 static bool kswapd_shrink_zone(struct zone *zone,
 			       int classzone_idx,
 			       struct scan_control *sc,
-			       unsigned long lru_pages,
 			       unsigned long *nr_attempted)
 {
 	int testorder = sc->order;
 	unsigned long balance_gap;
-	struct reclaim_state *reclaim_state = current->reclaim_state;
-	struct shrink_control shrink = {
-		.gfp_mask = sc->gfp_mask,
-	};
 	bool lowmem_pressure;
 
 	/* Reclaim above the high watermark. */
@@ -2975,13 +2986,7 @@ static bool kswapd_shrink_zone(struct zone *zone,
 						balance_gap, classzone_idx))
 		return true;
 
-	shrink_zone(zone, sc);
-	nodes_clear(shrink.nodes_to_scan);
-	node_set(zone_to_nid(zone), shrink.nodes_to_scan);
-
-	reclaim_state->reclaimed_slab = 0;
-	shrink_slab(&shrink, sc->nr_scanned, lru_pages);
-	sc->nr_reclaimed += reclaim_state->reclaimed_slab;
+	shrink_zone(zone, sc, zone_idx(zone) == classzone_idx);
 
 	/* Account for the number of pages attempted to reclaim */
 	*nr_attempted += sc->nr_to_reclaim;
@@ -3042,7 +3047,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
 	count_vm_event(PAGEOUTRUN);
 
 	do {
-		unsigned long lru_pages = 0;
 		unsigned long nr_attempted = 0;
 		bool raise_priority = true;
 		bool pgdat_needs_compaction = (order > 0);
@@ -3102,8 +3106,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
 			if (!populated_zone(zone))
 				continue;
 
-			lru_pages += zone_reclaimable_pages(zone);
-
 			/*
 			 * If any zone is currently balanced then kswapd will
 			 * not call compaction as it is expected that the
@@ -3159,8 +3161,8 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
 			 * that that high watermark would be met at 100%
 			 * efficiency.
 			 */
-			if (kswapd_shrink_zone(zone, end_zone, &sc,
-					lru_pages, &nr_attempted))
+			if (kswapd_shrink_zone(zone, end_zone,
+					       &sc, &nr_attempted))
 				raise_priority = false;
 		}
 
@@ -3612,10 +3614,6 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 		.may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP),
 		.may_swap = 1,
 	};
-	struct shrink_control shrink = {
-		.gfp_mask = sc.gfp_mask,
-	};
-	unsigned long nr_slab_pages0, nr_slab_pages1;
 
 	cond_resched();
 	/*
@@ -3634,44 +3632,10 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 		 * priorities until we have enough memory freed.
 		 */
 		do {
-			shrink_zone(zone, &sc);
+			shrink_zone(zone, &sc, true);
 		} while (sc.nr_reclaimed < nr_pages && --sc.priority >= 0);
 	}
 
-	nr_slab_pages0 = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
-	if (nr_slab_pages0 > zone->min_slab_pages) {
-		/*
-		 * shrink_slab() does not currently allow us to determine how
-		 * many pages were freed in this zone. So we take the current
-		 * number of slab pages and shake the slab until it is reduced
-		 * by the same nr_pages that we used for reclaiming unmapped
-		 * pages.
-		 */
-		nodes_clear(shrink.nodes_to_scan);
-		node_set(zone_to_nid(zone), shrink.nodes_to_scan);
-		for (;;) {
-			unsigned long lru_pages = zone_reclaimable_pages(zone);
-
-			/* No reclaimable slab or very low memory pressure */
-			if (!shrink_slab(&shrink, sc.nr_scanned, lru_pages))
-				break;
-
-			/* Freed enough memory */
-			nr_slab_pages1 = zone_page_state(zone,
-							NR_SLAB_RECLAIMABLE);
-			if (nr_slab_pages1 + nr_pages <= nr_slab_pages0)
-				break;
-		}
-
-		/*
-		 * Update nr_reclaimed by the number of slab pages we
-		 * reclaimed from this zone.
-		 */
-		nr_slab_pages1 = zone_page_state(zone, NR_SLAB_RECLAIMABLE);
-		if (nr_slab_pages1 < nr_slab_pages0)
-			sc.nr_reclaimed += nr_slab_pages0 - nr_slab_pages1;
-	}
-
 	p->reclaim_state = NULL;
 	current->flags &= ~(PF_MEMALLOC | PF_SWAPWRITE);
 	lockdep_clear_current_reclaim_state();