1 files changed, 126 insertions, 58 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c917720..faa0a08 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -173,7 +173,7 @@ static unsigned long zone_nr_lru_pages(struct zone *zone,
 				struct scan_control *sc, enum lru_list lru)
 {
 	if (!scanning_global_lru(sc))
-		return mem_cgroup_zone_nr_pages(sc->mem_cgroup, zone, lru);
+		return mem_cgroup_zone_nr_lru_pages(sc->mem_cgroup, zone, lru);
 
 	return zone_page_state(zone, NR_LRU_BASE + lru);
 }
@@ -202,6 +202,14 @@ void unregister_shrinker(struct shrinker *shrinker)
 }
 EXPORT_SYMBOL(unregister_shrinker);
 
+static inline int do_shrinker_shrink(struct shrinker *shrinker,
+				     struct shrink_control *sc,
+				     unsigned long nr_to_scan)
+{
+	sc->nr_to_scan = nr_to_scan;
+	return (*shrinker->shrink)(shrinker, sc);
+}
+
 #define SHRINK_BATCH 128
 /*
  * Call the shrink functions to age shrinkable caches
@@ -222,25 +230,29 @@ EXPORT_SYMBOL(unregister_shrinker);
  *
  * Returns the number of slab objects which we shrunk.
  */
-unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
-			unsigned long lru_pages)
+unsigned long shrink_slab(struct shrink_control *shrink,
+			  unsigned long nr_pages_scanned,
+			  unsigned long lru_pages)
 {
 	struct shrinker *shrinker;
 	unsigned long ret = 0;
 
-	if (scanned == 0)
-		scanned = SWAP_CLUSTER_MAX;
+	if (nr_pages_scanned == 0)
+		nr_pages_scanned = SWAP_CLUSTER_MAX;
 
-	if (!down_read_trylock(&shrinker_rwsem))
-		return 1;	/* Assume we'll be able to shrink next time */
+	if (!down_read_trylock(&shrinker_rwsem)) {
+		/* Assume we'll be able to shrink next time */
+		ret = 1;
+		goto out;
+	}
 
 	list_for_each_entry(shrinker, &shrinker_list, list) {
 		unsigned long long delta;
 		unsigned long total_scan;
 		unsigned long max_pass;
 
-		max_pass = (*shrinker->shrink)(shrinker, 0, gfp_mask);
-		delta = (4 * scanned) / shrinker->seeks;
+		max_pass = do_shrinker_shrink(shrinker, shrink, 0);
+		delta = (4 * nr_pages_scanned) / shrinker->seeks;
 		delta *= max_pass;
 		do_div(delta, lru_pages + 1);
 		shrinker->nr += delta;
@@ -267,9 +279,9 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
 			int shrink_ret;
 			int nr_before;
 
-			nr_before = (*shrinker->shrink)(shrinker, 0, gfp_mask);
-			shrink_ret = (*shrinker->shrink)(shrinker, this_scan,
-								gfp_mask);
+			nr_before = do_shrinker_shrink(shrinker, shrink, 0);
+			shrink_ret = do_shrinker_shrink(shrinker, shrink,
+							this_scan);
 			if (shrink_ret == -1)
 				break;
 			if (shrink_ret < nr_before)
@@ -283,6 +295,8 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
 		shrinker->nr += total_scan;
 	}
 	up_read(&shrinker_rwsem);
+out:
+	cond_resched();
 	return ret;
 }
 
@@ -1202,13 +1216,16 @@ int isolate_lru_page(struct page *page)
 {
 	int ret = -EBUSY;
 
+	VM_BUG_ON(!page_count(page));
+
 	if (PageLRU(page)) {
 		struct zone *zone = page_zone(page);
 
 		spin_lock_irq(&zone->lru_lock);
-		if (PageLRU(page) && get_page_unless_zero(page)) {
+		if (PageLRU(page)) {
 			int lru = page_lru(page);
 			ret = 0;
+			get_page(page);
 			ClearPageLRU(page);
 
 			del_page_from_lru_list(zone, page, lru);
@@ -1701,26 +1718,6 @@ static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
 }
 
 /*
- * Smallish @nr_to_scan's are deposited in @nr_saved_scan,
- * until we collected @swap_cluster_max pages to scan.
- */
-static unsigned long nr_scan_try_batch(unsigned long nr_to_scan,
-				       unsigned long *nr_saved_scan)
-{
-	unsigned long nr;
-
-	*nr_saved_scan += nr_to_scan;
-	nr = *nr_saved_scan;
-
-	if (nr >= SWAP_CLUSTER_MAX)
-		*nr_saved_scan = 0;
-	else
-		nr = 0;
-
-	return nr;
-}
-
-/*
  * Determine how aggressively the anon and file LRU lists should be
  * scanned.  The relative value of each set of LRU lists is determined
  * by looking at the fraction of the pages scanned we did rotate back
@@ -1738,6 +1735,22 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc,
 	u64 fraction[2], denominator;
 	enum lru_list l;
 	int noswap = 0;
+	int force_scan = 0;
+
+
+	anon  = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) +
+		zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON);
+	file  = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) +
+		zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE);
+
+	if (((anon + file) >> priority) < SWAP_CLUSTER_MAX) {
+		/* kswapd does zone balancing and need to scan this zone */
+		if (scanning_global_lru(sc) && current_is_kswapd())
+			force_scan = 1;
+		/* memcg may have small limit and need to avoid priority drop */
+		if (!scanning_global_lru(sc))
+			force_scan = 1;
+	}
 
 	/* If we have no swap space, do not bother scanning anon pages. */
 	if (!sc->may_swap || (nr_swap_pages <= 0)) {
@@ -1748,11 +1761,6 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc,
 		goto out;
 	}
 
-	anon  = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_ANON) +
-		zone_nr_lru_pages(zone, sc, LRU_INACTIVE_ANON);
-	file  = zone_nr_lru_pages(zone, sc, LRU_ACTIVE_FILE) +
-		zone_nr_lru_pages(zone, sc, LRU_INACTIVE_FILE);
-
 	if (scanning_global_lru(sc)) {
 		free  = zone_page_state(zone, NR_FREE_PAGES);
 		/* If we have very few page cache pages,
@@ -1819,8 +1827,23 @@ out:
 			scan >>= priority;
 			scan = div64_u64(scan * fraction[file], denominator);
 		}
-		nr[l] = nr_scan_try_batch(scan,
-					  &reclaim_stat->nr_saved_scan[l]);
+
+		/*
+		 * If zone is small or memcg is small, nr[l] can be 0.
+		 * This results no-scan on this priority and priority drop down.
+		 * For global direct reclaim, it can visit next zone and tend
+		 * not to have problems. For global kswapd, it's for zone
+		 * balancing and it need to scan a small amounts. When using
+		 * memcg, priority drop can cause big latency. So, it's better
+		 * to scan small amount. See may_noscan above.
+		 */
+		if (!scan && force_scan) {
+			if (file)
+				scan = SWAP_CLUSTER_MAX;
+			else if (!noswap)
+				scan = SWAP_CLUSTER_MAX;
+		}
+		nr[l] = scan;
 	}
 }
 
@@ -1960,11 +1983,14 @@ restart:
  * If a zone is deemed to be full of pinned pages then just give it a light
  * scan then give up on it.
  */
-static void shrink_zones(int priority, struct zonelist *zonelist,
+static unsigned long shrink_zones(int priority, struct zonelist *zonelist,
 					struct scan_control *sc)
 {
 	struct zoneref *z;
 	struct zone *zone;
+	unsigned long nr_soft_reclaimed;
+	unsigned long nr_soft_scanned;
+	unsigned long total_scanned = 0;
 
 	for_each_zone_zonelist_nodemask(zone, z, zonelist,
 					gfp_zone(sc->gfp_mask), sc->nodemask) {
@@ -1981,8 +2007,17 @@ static void shrink_zones(int priority, struct zonelist *zonelist,
 				continue;	/* Let kswapd poll it */
 		}
 
+		nr_soft_scanned = 0;
+		nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone,
+							sc->order, sc->gfp_mask,
+							&nr_soft_scanned);
+		sc->nr_reclaimed += nr_soft_reclaimed;
+		total_scanned += nr_soft_scanned;
+
 		shrink_zone(priority, zone, sc);
 	}
+
+	return total_scanned;
 }
 
 static bool zone_reclaimable(struct zone *zone)
@@ -2027,7 +2062,8 @@ static bool all_unreclaimable(struct zonelist *zonelist,
  * 		else, the number of pages reclaimed
  */
 static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
-					struct scan_control *sc)
+					struct scan_control *sc,
+					struct shrink_control *shrink)
 {
 	int priority;
 	unsigned long total_scanned = 0;
@@ -2046,7 +2082,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
 		sc->nr_scanned = 0;
 		if (!priority)
 			disable_swap_token();
-		shrink_zones(priority, zonelist, sc);
+		total_scanned += shrink_zones(priority, zonelist, sc);
 		/*
 		 * Don't shrink slabs when reclaiming memory from
 		 * over limit cgroups
@@ -2061,7 +2097,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
 				lru_pages += zone_reclaimable_pages(zone);
 			}
 
-			shrink_slab(sc->nr_scanned, sc->gfp_mask, lru_pages);
+			shrink_slab(shrink, sc->nr_scanned, lru_pages);
 			if (reclaim_state) {
 				sc->nr_reclaimed += reclaim_state->reclaimed_slab;
 				reclaim_state->reclaimed_slab = 0;
@@ -2133,12 +2169,15 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 		.mem_cgroup = NULL,
 		.nodemask = nodemask,
 	};
+	struct shrink_control shrink = {
+		.gfp_mask = sc.gfp_mask,
+	};
 
 	trace_mm_vmscan_direct_reclaim_begin(order,
 				sc.may_writepage,
 				gfp_mask);
 
-	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
+	nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
 
 	trace_mm_vmscan_direct_reclaim_end(nr_reclaimed);
 
@@ -2150,9 +2189,11 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
 						gfp_t gfp_mask, bool noswap,
 						unsigned int swappiness,
-						struct zone *zone)
+						struct zone *zone,
+						unsigned long *nr_scanned)
 {
 	struct scan_control sc = {
+		.nr_scanned = 0,
 		.nr_to_reclaim = SWAP_CLUSTER_MAX,
 		.may_writepage = !laptop_mode,
 		.may_unmap = 1,
@@ -2161,6 +2202,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
 		.order = 0,
 		.mem_cgroup = mem,
 	};
+
 	sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
 			(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
 
@@ -2179,6 +2221,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
 
 	trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);
 
+	*nr_scanned = sc.nr_scanned;
 	return sc.nr_reclaimed;
 }
 
@@ -2189,6 +2232,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
 {
 	struct zonelist *zonelist;
 	unsigned long nr_reclaimed;
+	int nid;
 	struct scan_control sc = {
 		.may_writepage = !laptop_mode,
 		.may_unmap = 1,
@@ -2198,17 +2242,27 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
 		.order = 0,
 		.mem_cgroup = mem_cont,
 		.nodemask = NULL, /* we don't care the placement */
+		.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
+				(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK),
+	};
+	struct shrink_control shrink = {
+		.gfp_mask = sc.gfp_mask,
 	};
 
-	sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
-			(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
-	zonelist = NODE_DATA(numa_node_id())->node_zonelists;
+	/*
+	 * Unlike direct reclaim via alloc_pages(), memcg's reclaim doesn't
+	 * take care of from where we get pages. So the node where we start the
+	 * scan does not need to be the current node.
+	 */
+	nid = mem_cgroup_select_victim_node(mem_cont);
+
+	zonelist = NODE_DATA(nid)->node_zonelists;
 
 	trace_mm_vmscan_memcg_reclaim_begin(0,
 					    sc.may_writepage,
 					    sc.gfp_mask);
 
-	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
+	nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
 
 	trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed);
 
@@ -2287,7 +2341,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining,
 	 * must be balanced
 	 */
 	if (order)
-		return pgdat_balanced(pgdat, balanced, classzone_idx);
+		return !pgdat_balanced(pgdat, balanced, classzone_idx);
 	else
 		return !all_zones_ok;
 }
@@ -2323,6 +2377,8 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
 	int end_zone = 0;	/* Inclusive.  0 = ZONE_DMA */
 	unsigned long total_scanned;
 	struct reclaim_state *reclaim_state = current->reclaim_state;
+	unsigned long nr_soft_reclaimed;
+	unsigned long nr_soft_scanned;
 	struct scan_control sc = {
 		.gfp_mask = GFP_KERNEL,
 		.may_unmap = 1,
@@ -2336,6 +2392,9 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
 		.order = order,
 		.mem_cgroup = NULL,
 	};
+	struct shrink_control shrink = {
+		.gfp_mask = sc.gfp_mask,
+	};
 loop_again:
 	total_scanned = 0;
 	sc.nr_reclaimed = 0;
@@ -2412,11 +2471,15 @@ loop_again:
 
 			sc.nr_scanned = 0;
 
+			nr_soft_scanned = 0;
 			/*
 			 * Call soft limit reclaim before calling shrink_zone.
-			 * For now we ignore the return value
 			 */
-			mem_cgroup_soft_limit_reclaim(zone, order, sc.gfp_mask);
+			nr_soft_reclaimed = mem_cgroup_soft_limit_reclaim(zone,
+							order, sc.gfp_mask,
+							&nr_soft_scanned);
+			sc.nr_reclaimed += nr_soft_reclaimed;
+			total_scanned += nr_soft_scanned;
 
 			/*
 			 * We put equal pressure on every zone, unless
@@ -2435,8 +2498,7 @@ loop_again:
 					end_zone, 0))
 				shrink_zone(priority, zone, &sc);
 			reclaim_state->reclaimed_slab = 0;
-			nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
-						lru_pages);
+			nr_slab = shrink_slab(&shrink, sc.nr_scanned, lru_pages);
 			sc.nr_reclaimed += reclaim_state->reclaimed_slab;
 			total_scanned += sc.nr_scanned;
 
@@ -2788,7 +2850,10 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
 		.swappiness = vm_swappiness,
 		.order = 0,
 	};
-	struct zonelist * zonelist = node_zonelist(numa_node_id(), sc.gfp_mask);
+	struct shrink_control shrink = {
+		.gfp_mask = sc.gfp_mask,
+	};
+	struct zonelist *zonelist = node_zonelist(numa_node_id(), sc.gfp_mask);
 	struct task_struct *p = current;
 	unsigned long nr_reclaimed;
 
@@ -2797,7 +2862,7 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
 	reclaim_state.reclaimed_slab = 0;
 	p->reclaim_state = &reclaim_state;
 
-	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
+	nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
 
 	p->reclaim_state = NULL;
 	lockdep_clear_current_reclaim_state();
@@ -2972,6 +3037,9 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 		.swappiness = vm_swappiness,
 		.order = order,
 	};
+	struct shrink_control shrink = {
+		.gfp_mask = sc.gfp_mask,
+	};
 	unsigned long nr_slab_pages0, nr_slab_pages1;
 
 	cond_resched();
@@ -3013,7 +3081,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 			unsigned long lru_pages = zone_reclaimable_pages(zone);
 
 			/* No reclaimable slab or very low memory pressure */
-			if (!shrink_slab(sc.nr_scanned, gfp_mask, lru_pages))
+			if (!shrink_slab(&shrink, sc.nr_scanned, lru_pages))
 				break;
 
 			/* Freed enough memory */