1 files changed, 113 insertions, 120 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index eea668d9cff6..9b6497eda806 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -147,7 +147,7 @@ static bool global_reclaim(struct scan_control *sc)
 }
 #endif
 
-unsigned long zone_reclaimable_pages(struct zone *zone)
+static unsigned long zone_reclaimable_pages(struct zone *zone)
 {
 	int nr;
 
@@ -224,15 +224,15 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
 	unsigned long freed = 0;
 	unsigned long long delta;
 	long total_scan;
-	long max_pass;
+	long freeable;
 	long nr;
 	long new_nr;
 	int nid = shrinkctl->nid;
 	long batch_size = shrinker->batch ? shrinker->batch
 					  : SHRINK_BATCH;
 
-	max_pass = shrinker->count_objects(shrinker, shrinkctl);
-	if (max_pass == 0)
+	freeable = shrinker->count_objects(shrinker, shrinkctl);
+	if (freeable == 0)
 		return 0;
 
 	/*
@@ -244,14 +244,14 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
 
 	total_scan = nr;
 	delta = (4 * nr_pages_scanned) / shrinker->seeks;
-	delta *= max_pass;
+	delta *= freeable;
 	do_div(delta, lru_pages + 1);
 	total_scan += delta;
 	if (total_scan < 0) {
 		printk(KERN_ERR
 		"shrink_slab: %pF negative objects to delete nr=%ld\n",
 		       shrinker->scan_objects, total_scan);
-		total_scan = max_pass;
+		total_scan = freeable;
 	}
 
 	/*
@@ -260,38 +260,55 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker,
 	 * shrinkers to return -1 all the time. This results in a large
 	 * nr being built up so when a shrink that can do some work
 	 * comes along it empties the entire cache due to nr >>>
-	 * max_pass.  This is bad for sustaining a working set in
+	 * freeable. This is bad for sustaining a working set in
 	 * memory.
 	 *
 	 * Hence only allow the shrinker to scan the entire cache when
 	 * a large delta change is calculated directly.
 	 */
-	if (delta < max_pass / 4)
-		total_scan = min(total_scan, max_pass / 2);
+	if (delta < freeable / 4)
+		total_scan = min(total_scan, freeable / 2);
 
 	/*
 	 * Avoid risking looping forever due to too large nr value:
 	 * never try to free more than twice the estimate number of
 	 * freeable entries.
 	 */
-	if (total_scan > max_pass * 2)
-		total_scan = max_pass * 2;
+	if (total_scan > freeable * 2)
+		total_scan = freeable * 2;
 
 	trace_mm_shrink_slab_start(shrinker, shrinkctl, nr,
 				nr_pages_scanned, lru_pages,
-				max_pass, delta, total_scan);
+				freeable, delta, total_scan);
 
-	while (total_scan >= batch_size) {
+	/*
+	 * Normally, we should not scan less than batch_size objects in one
+	 * pass to avoid too frequent shrinker calls, but if the slab has less
+	 * than batch_size objects in total and we are really tight on memory,
+	 * we will try to reclaim all available objects, otherwise we can end
+	 * up failing allocations although there are plenty of reclaimable
+	 * objects spread over several slabs with usage less than the
+	 * batch_size.
+	 *
+	 * We detect the "tight on memory" situations by looking at the total
+	 * number of objects we want to scan (total_scan). If it is greater
+	 * than the total number of objects on slab (freeable), we must be
+	 * scanning at high prio and therefore should try to reclaim as much as
+	 * possible.
+	 */
+	while (total_scan >= batch_size ||
+	       total_scan >= freeable) {
 		unsigned long ret;
+		unsigned long nr_to_scan = min(batch_size, total_scan);
 
-		shrinkctl->nr_to_scan = batch_size;
+		shrinkctl->nr_to_scan = nr_to_scan;
 		ret = shrinker->scan_objects(shrinker, shrinkctl);
 		if (ret == SHRINK_STOP)
 			break;
 		freed += ret;
 
-		count_vm_events(SLABS_SCANNED, batch_size);
-		total_scan -= batch_size;
+		count_vm_events(SLABS_SCANNED, nr_to_scan);
+		total_scan -= nr_to_scan;
 
 		cond_resched();
 	}
@@ -352,16 +369,17 @@ unsigned long shrink_slab(struct shrink_control *shrinkctl,
 	}
 
 	list_for_each_entry(shrinker, &shrinker_list, list) {
-		for_each_node_mask(shrinkctl->nid, shrinkctl->nodes_to_scan) {
-			if (!node_online(shrinkctl->nid))
-				continue;
-
-			if (!(shrinker->flags & SHRINKER_NUMA_AWARE) &&
-			    (shrinkctl->nid != 0))
-				break;
-
+		if (!(shrinker->flags & SHRINKER_NUMA_AWARE)) {
+			shrinkctl->nid = 0;
 			freed += shrink_slab_node(shrinkctl, shrinker,
-				 nr_pages_scanned, lru_pages);
+					nr_pages_scanned, lru_pages);
+			continue;
+		}
+
+		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);
 
 		}
 	}
@@ -505,7 +523,8 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
  * Same as remove_mapping, but if the page is removed from the mapping, it
  * gets returned with a refcount of 0.
  */
-static int __remove_mapping(struct address_space *mapping, struct page *page)
+static int __remove_mapping(struct address_space *mapping, struct page *page,
+			    bool reclaimed)
 {
 	BUG_ON(!PageLocked(page));
 	BUG_ON(mapping != page_mapping(page));
@@ -551,10 +570,23 @@ static int __remove_mapping(struct address_space *mapping, struct page *page)
 		swapcache_free(swap, page);
 	} else {
 		void (*freepage)(struct page *);
+		void *shadow = NULL;
 
 		freepage = mapping->a_ops->freepage;
-
-		__delete_from_page_cache(page);
+		/*
+		 * Remember a shadow entry for reclaimed file cache in
+		 * order to detect refaults, thus thrashing, later on.
+		 *
+		 * But don't store shadows in an address space that is
+		 * already exiting.  This is not just an optizimation,
+		 * inode reclaim needs to empty out the radix tree or
+		 * the nodes are lost.  Don't plant shadows behind its
+		 * back.
+		 */
+		if (reclaimed && page_is_file_cache(page) &&
+		    !mapping_exiting(mapping))
+			shadow = workingset_eviction(mapping, page);
+		__delete_from_page_cache(page, shadow);
 		spin_unlock_irq(&mapping->tree_lock);
 		mem_cgroup_uncharge_cache_page(page);
 
@@ -577,7 +609,7 @@ cannot_free:
  */
 int remove_mapping(struct address_space *mapping, struct page *page)
 {
-	if (__remove_mapping(mapping, page)) {
+	if (__remove_mapping(mapping, page, false)) {
 		/*
 		 * Unfreezing the refcount with 1 rather than 2 effectively
 		 * drops the pagecache ref for us without requiring another
@@ -603,7 +635,7 @@ void putback_lru_page(struct page *page)
 	bool is_unevictable;
 	int was_unevictable = PageUnevictable(page);
 
-	VM_BUG_ON(PageLRU(page));
+	VM_BUG_ON_PAGE(PageLRU(page), page);
 
 redo:
 	ClearPageUnevictable(page);
@@ -794,8 +826,8 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 		if (!trylock_page(page))
 			goto keep;
 
-		VM_BUG_ON(PageActive(page));
-		VM_BUG_ON(page_zone(page) != zone);
+		VM_BUG_ON_PAGE(PageActive(page), page);
+		VM_BUG_ON_PAGE(page_zone(page) != zone, page);
 
 		sc->nr_scanned++;
 
@@ -1047,7 +1079,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 			}
 		}
 
-		if (!mapping || !__remove_mapping(mapping, page))
+		if (!mapping || !__remove_mapping(mapping, page, true))
 			goto keep_locked;
 
 		/*
@@ -1079,14 +1111,14 @@ activate_locked:
 		/* Not a candidate for swapping, so reclaim swap space. */
 		if (PageSwapCache(page) && vm_swap_full())
 			try_to_free_swap(page);
-		VM_BUG_ON(PageActive(page));
+		VM_BUG_ON_PAGE(PageActive(page), page);
 		SetPageActive(page);
 		pgactivate++;
 keep_locked:
 		unlock_page(page);
 keep:
 		list_add(&page->lru, &ret_pages);
-		VM_BUG_ON(PageLRU(page) || PageUnevictable(page));
+		VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page), page);
 	}
 
 	free_hot_cold_page_list(&free_pages, 1);
@@ -1240,7 +1272,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 		page = lru_to_page(src);
 		prefetchw_prev_lru_page(page, src, flags);
 
-		VM_BUG_ON(!PageLRU(page));
+		VM_BUG_ON_PAGE(!PageLRU(page), page);
 
 		switch (__isolate_lru_page(page, mode)) {
 		case 0:
@@ -1295,7 +1327,7 @@ int isolate_lru_page(struct page *page)
 {
 	int ret = -EBUSY;
 
-	VM_BUG_ON(!page_count(page));
+	VM_BUG_ON_PAGE(!page_count(page), page);
 
 	if (PageLRU(page)) {
 		struct zone *zone = page_zone(page);
@@ -1366,7 +1398,7 @@ putback_inactive_pages(struct lruvec *lruvec, struct list_head *page_list)
 		struct page *page = lru_to_page(page_list);
 		int lru;
 
-		VM_BUG_ON(PageLRU(page));
+		VM_BUG_ON_PAGE(PageLRU(page), page);
 		list_del(&page->lru);
 		if (unlikely(!page_evictable(page))) {
 			spin_unlock_irq(&zone->lru_lock);
@@ -1586,7 +1618,7 @@ static void move_active_pages_to_lru(struct lruvec *lruvec,
 		page = lru_to_page(list);
 		lruvec = mem_cgroup_page_lruvec(page, zone);
 
-		VM_BUG_ON(PageLRU(page));
+		VM_BUG_ON_PAGE(PageLRU(page), page);
 		SetPageLRU(page);
 
 		nr_pages = hpage_nr_pages(page);
@@ -1830,7 +1862,7 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 	struct zone *zone = lruvec_zone(lruvec);
 	unsigned long anon_prio, file_prio;
 	enum scan_balance scan_balance;
-	unsigned long anon, file, free;
+	unsigned long anon, file;
 	bool force_scan = false;
 	unsigned long ap, fp;
 	enum lru_list lru;
@@ -1884,20 +1916,6 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc,
 		get_lru_size(lruvec, LRU_INACTIVE_FILE);
 
 	/*
-	 * If it's foreseeable that reclaiming the file cache won't be
-	 * enough to get the zone back into a desirable shape, we have
-	 * to swap.  Better start now and leave the - probably heavily
-	 * thrashing - remaining file pages alone.
-	 */
-	if (global_reclaim(sc)) {
-		free = zone_page_state(zone, NR_FREE_PAGES);
-		if (unlikely(file + free <= high_wmark_pages(zone))) {
-			scan_balance = SCAN_ANON;
-			goto out;
-		}
-	}
-
-	/*
 	 * There is enough inactive page cache, do not reclaim
 	 * anything from the anonymous working set right now.
 	 */
@@ -2279,16 +2297,26 @@ 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;
 	bool aborted_reclaim = false;
+	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);
 
 	/*
 	 * If the number of buffer_heads in the machine exceeds the maximum
 	 * allowed level, force direct reclaim to scan the highmem zone as
 	 * highmem pages could be pinning lowmem pages storing buffer_heads
 	 */
+	orig_mask = sc->gfp_mask;
 	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) {
 		if (!populated_zone(zone))
@@ -2300,6 +2328,10 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 		if (global_reclaim(sc)) {
 			if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
 				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 */
@@ -2313,7 +2345,8 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 				 * noticeable problem, like transparent huge
 				 * page allocations.
 				 */
-				if (compaction_ready(zone, sc)) {
+				if ((zonelist_zone_idx(z) <= requested_highidx)
+				    && compaction_ready(zone, sc)) {
 					aborted_reclaim = true;
 					continue;
 				}
@@ -2336,6 +2369,26 @@ static bool shrink_zones(struct zonelist *zonelist, struct scan_control *sc)
 		shrink_zone(zone, 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.
+	 */
+	sc->gfp_mask = orig_mask;
+
 	return aborted_reclaim;
 }
 
@@ -2376,13 +2429,9 @@ 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 shrink_control *shrink)
+					  struct scan_control *sc)
 {
 	unsigned long total_scanned = 0;
-	struct reclaim_state *reclaim_state = current->reclaim_state;
-	struct zoneref *z;
-	struct zone *zone;
 	unsigned long writeback_threshold;
 	bool aborted_reclaim;
 
@@ -2397,32 +2446,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
 		sc->nr_scanned = 0;
 		aborted_reclaim = shrink_zones(zonelist, 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)) {
-			unsigned long lru_pages = 0;
-
-			nodes_clear(shrink->nodes_to_scan);
-			for_each_zone_zonelist(zone, z, zonelist,
-					gfp_zone(sc->gfp_mask)) {
-				if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
-					continue;
-
-				lru_pages += zone_reclaimable_pages(zone);
-				node_set(zone_to_nid(zone),
-					 shrink->nodes_to_scan);
-			}
-
-			shrink_slab(shrink, sc->nr_scanned, lru_pages);
-			if (reclaim_state) {
-				sc->nr_reclaimed += reclaim_state->reclaimed_slab;
-				reclaim_state->reclaimed_slab = 0;
-			}
-		}
 		total_scanned += sc->nr_scanned;
 		if (sc->nr_reclaimed >= sc->nr_to_reclaim)
 			goto out;
@@ -2584,9 +2607,6 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 		.target_mem_cgroup = NULL,
 		.nodemask = nodemask,
 	};
-	struct shrink_control shrink = {
-		.gfp_mask = sc.gfp_mask,
-	};
 
 	/*
 	 * Do not enter reclaim if fatal signal was delivered while throttled.
@@ -2600,7 +2620,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 				sc.may_writepage,
 				gfp_mask);
 
-	nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
+	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
 
 	trace_mm_vmscan_direct_reclaim_end(nr_reclaimed);
 
@@ -2667,9 +2687,6 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 		.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
 				(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK),
 	};
-	struct shrink_control shrink = {
-		.gfp_mask = sc.gfp_mask,
-	};
 
 	/*
 	 * Unlike direct reclaim via alloc_pages(), memcg's reclaim doesn't
@@ -2684,7 +2701,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
 					    sc.may_writepage,
 					    sc.gfp_mask);
 
-	nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
+	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
 
 	trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed);
 
@@ -3297,27 +3314,6 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx)
 	wake_up_interruptible(&pgdat->kswapd_wait);
 }
 
-/*
- * The reclaimable count would be mostly accurate.
- * The less reclaimable pages may be
- * - mlocked pages, which will be moved to unevictable list when encountered
- * - mapped pages, which may require several travels to be reclaimed
- * - dirty pages, which is not "instantly" reclaimable
- */
-unsigned long global_reclaimable_pages(void)
-{
-	int nr;
-
-	nr = global_page_state(NR_ACTIVE_FILE) +
-	     global_page_state(NR_INACTIVE_FILE);
-
-	if (get_nr_swap_pages() > 0)
-		nr += global_page_state(NR_ACTIVE_ANON) +
-		      global_page_state(NR_INACTIVE_ANON);
-
-	return nr;
-}
-
 #ifdef CONFIG_HIBERNATION
 /*
  * Try to free `nr_to_reclaim' of memory, system-wide, and return the number of
@@ -3340,9 +3336,6 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
 		.order = 0,
 		.priority = DEF_PRIORITY,
 	};
-	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;
@@ -3352,7 +3345,7 @@ 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, &shrink);
+	nr_reclaimed = do_try_to_free_pages(zonelist, &sc);
 
 	p->reclaim_state = NULL;
 	lockdep_clear_current_reclaim_state();
@@ -3701,7 +3694,7 @@ void check_move_unevictable_pages(struct page **pages, int nr_pages)
 		if (page_evictable(page)) {
 			enum lru_list lru = page_lru_base_type(page);
 
-			VM_BUG_ON(PageActive(page));
+			VM_BUG_ON_PAGE(PageActive(page), page);
 			ClearPageUnevictable(page);
 			del_page_from_lru_list(page, lruvec, LRU_UNEVICTABLE);
 			add_page_to_lru_list(page, lruvec, lru);