1 files changed, 238 insertions, 138 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 5fa3eda1f03f..4139aa52b941 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -470,10 +470,11 @@ static int __remove_mapping(struct address_space *mapping, struct page *page)
                 swp_entry_t swap = { .val = page_private(page) };
                 __delete_from_swap_cache(page);
                 spin_unlock_irq(&mapping->tree_lock);
-                swap_free(swap);
+                swapcache_free(swap, page);
         } else {
                 __remove_from_page_cache(page);
                 spin_unlock_irq(&mapping->tree_lock);
+                mem_cgroup_uncharge_cache_page(page);
         }
 
         return 1;
@@ -512,7 +513,6 @@ int remove_mapping(struct address_space *mapping, struct page *page)
  *
  * lru_lock must not be held, interrupts must be enabled.
  */
-#ifdef CONFIG_UNEVICTABLE_LRU
 void putback_lru_page(struct page *page)
 {
         int lru;
@@ -566,20 +566,6 @@ redo:
         put_page(page);         /* drop ref from isolate */
 }
 
-#else /* CONFIG_UNEVICTABLE_LRU */
-
-void putback_lru_page(struct page *page)
-{
-        int lru;
-        VM_BUG_ON(PageLRU(page));
-
-        lru = !!TestClearPageActive(page) + page_is_file_cache(page);
-        lru_cache_add_lru(page, lru);
-        put_page(page);
-}
-#endif /* CONFIG_UNEVICTABLE_LRU */
-
-
 /*
  * shrink_page_list() returns the number of reclaimed pages
  */
@@ -591,6 +577,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
         struct pagevec freed_pvec;
         int pgactivate = 0;
         unsigned long nr_reclaimed = 0;
+        unsigned long vm_flags;
 
         cond_resched();
 
@@ -641,7 +628,8 @@ static unsigned long shrink_page_list(struct list_head *page_list,
                                 goto keep_locked;
                 }
 
-                referenced = page_referenced(page, 1, sc->mem_cgroup);
+                referenced = page_referenced(page, 1,
+                                                sc->mem_cgroup, &vm_flags);
                 /* In active use or really unfreeable?  Activate it. */
                 if (sc->order <= PAGE_ALLOC_COSTLY_ORDER &&
                                         referenced && page_mapping_inuse(page))
@@ -941,18 +929,10 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
                         /* Check that we have not crossed a zone boundary. */
                         if (unlikely(page_zone_id(cursor_page) != zone_id))
                                 continue;
-                        switch (__isolate_lru_page(cursor_page, mode, file)) {
-                        case 0:
+                        if (__isolate_lru_page(cursor_page, mode, file) == 0) {
                                 list_move(&cursor_page->lru, dst);
                                 nr_taken++;
                                 scan++;
-                                break;
-
-                        case -EBUSY:
-                                /* else it is being freed elsewhere */
-                                list_move(&cursor_page->lru, src);
-                        default:
-                                break;  /* ! on LRU or wrong list */
                         }
                 }
         }
@@ -1059,6 +1039,19 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
         unsigned long nr_scanned = 0;
         unsigned long nr_reclaimed = 0;
         struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
+        int lumpy_reclaim = 0;
+
+        /*
+         * If we need a large contiguous chunk of memory, or have
+         * trouble getting a small set of contiguous pages, we
+         * will reclaim both active and inactive pages.
+         *
+         * We use the same threshold as pageout congestion_wait below.
+         */
+        if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
+                lumpy_reclaim = 1;
+        else if (sc->order && priority < DEF_PRIORITY - 2)
+                lumpy_reclaim = 1;
 
         pagevec_init(&pvec, 1);
 
@@ -1071,19 +1064,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
                 unsigned long nr_freed;
                 unsigned long nr_active;
                 unsigned int count[NR_LRU_LISTS] = { 0, };
-                int mode = ISOLATE_INACTIVE;
-
-                /*
-                 * If we need a large contiguous chunk of memory, or have
-                 * trouble getting a small set of contiguous pages, we
-                 * will reclaim both active and inactive pages.
-                 *
-                 * We use the same threshold as pageout congestion_wait below.
-                 */
-                if (sc->order > PAGE_ALLOC_COSTLY_ORDER)
-                        mode = ISOLATE_BOTH;
-                else if (sc->order && priority < DEF_PRIORITY - 2)
-                        mode = ISOLATE_BOTH;
+                int mode = lumpy_reclaim ? ISOLATE_BOTH : ISOLATE_INACTIVE;
 
                 nr_taken = sc->isolate_pages(sc->swap_cluster_max,
                              &page_list, &nr_scan, sc->order, mode,
@@ -1120,7 +1101,7 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,
                  * but that should be acceptable to the caller
                  */
                 if (nr_freed < nr_taken && !current_is_kswapd() &&
-                                        sc->order > PAGE_ALLOC_COSTLY_ORDER) {
+                    lumpy_reclaim) {
                         congestion_wait(WRITE, HZ/10);
 
                         /*
@@ -1215,18 +1196,54 @@ static inline void note_zone_scanning_priority(struct zone *zone, int priority)
  * But we had to alter page->flags anyway.
  */
 
+static void move_active_pages_to_lru(struct zone *zone,
+                                     struct list_head *list,
+                                     enum lru_list lru)
+{
+        unsigned long pgmoved = 0;
+        struct pagevec pvec;
+        struct page *page;
+
+        pagevec_init(&pvec, 1);
+
+        while (!list_empty(list)) {
+                page = lru_to_page(list);
+                prefetchw_prev_lru_page(page, list, flags);
+
+                VM_BUG_ON(PageLRU(page));
+                SetPageLRU(page);
+
+                VM_BUG_ON(!PageActive(page));
+                if (!is_active_lru(lru))
+                        ClearPageActive(page);  /* we are de-activating */
+
+                list_move(&page->lru, &zone->lru[lru].list);
+                mem_cgroup_add_lru_list(page, lru);
+                pgmoved++;
+
+                if (!pagevec_add(&pvec, page) || list_empty(list)) {
+                        spin_unlock_irq(&zone->lru_lock);
+                        if (buffer_heads_over_limit)
+                                pagevec_strip(&pvec);
+                        __pagevec_release(&pvec);
+                        spin_lock_irq(&zone->lru_lock);
+                }
+        }
+        __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
+        if (!is_active_lru(lru))
+                __count_vm_events(PGDEACTIVATE, pgmoved);
+}
 
 static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
                         struct scan_control *sc, int priority, int file)
 {
         unsigned long pgmoved;
-        int pgdeactivate = 0;
         unsigned long pgscanned;
+        unsigned long vm_flags;
         LIST_HEAD(l_hold);      /* The pages which were snipped off */
+        LIST_HEAD(l_active);
         LIST_HEAD(l_inactive);
         struct page *page;
-        struct pagevec pvec;
-        enum lru_list lru;
         struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
 
         lru_add_drain();
@@ -1243,13 +1260,14 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
         }
         reclaim_stat->recent_scanned[!!file] += pgmoved;
 
+        __count_zone_vm_events(PGREFILL, zone, pgscanned);
         if (file)
                 __mod_zone_page_state(zone, NR_ACTIVE_FILE, -pgmoved);
         else
                 __mod_zone_page_state(zone, NR_ACTIVE_ANON, -pgmoved);
         spin_unlock_irq(&zone->lru_lock);
 
-        pgmoved = 0;
+        pgmoved = 0;  /* count referenced (mapping) mapped pages */
         while (!list_empty(&l_hold)) {
                 cond_resched();
                 page = lru_to_page(&l_hold);
@@ -1262,58 +1280,44 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
 
                 /* page_referenced clears PageReferenced */
                 if (page_mapping_inuse(page) &&
-                    page_referenced(page, 0, sc->mem_cgroup))
+                    page_referenced(page, 0, sc->mem_cgroup, &vm_flags)) {
                         pgmoved++;
+                        /*
+                         * Identify referenced, file-backed active pages and
+                         * give them one more trip around the active list. So
+                         * that executable code get better chances to stay in
+                         * memory under moderate memory pressure.  Anon pages
+                         * are not likely to be evicted by use-once streaming
+                         * IO, plus JVM can create lots of anon VM_EXEC pages,
+                         * so we ignore them here.
+                         */
+                        if ((vm_flags & VM_EXEC) && !PageAnon(page)) {
+                                list_add(&page->lru, &l_active);
+                                continue;
+                        }
+                }
 
                 list_add(&page->lru, &l_inactive);
         }
 
         /*
-         * Move the pages to the [file or anon] inactive list.
+         * Move pages back to the lru list.
          */
-        pagevec_init(&pvec, 1);
-        lru = LRU_BASE + file * LRU_FILE;
-
         spin_lock_irq(&zone->lru_lock);
         /*
-         * Count referenced pages from currently used mappings as
-         * rotated, even though they are moved to the inactive list.
-         * This helps balance scan pressure between file and anonymous
-         * pages in get_scan_ratio.
+         * Count referenced pages from currently used mappings as rotated,
+         * even though only some of them are actually re-activated.  This
+         * helps balance scan pressure between file and anonymous pages in
+         * get_scan_ratio.
          */
         reclaim_stat->recent_rotated[!!file] += pgmoved;
 
-        pgmoved = 0;
-        while (!list_empty(&l_inactive)) {
-                page = lru_to_page(&l_inactive);
-                prefetchw_prev_lru_page(page, &l_inactive, flags);
-                VM_BUG_ON(PageLRU(page));
-                SetPageLRU(page);
-                VM_BUG_ON(!PageActive(page));
-                ClearPageActive(page);
+        move_active_pages_to_lru(zone, &l_active,
+                                                LRU_ACTIVE + file * LRU_FILE);
+        move_active_pages_to_lru(zone, &l_inactive,
+                                                LRU_BASE   + file * LRU_FILE);
 
-                list_move(&page->lru, &zone->lru[lru].list);
-                mem_cgroup_add_lru_list(page, lru);
-                pgmoved++;
-                if (!pagevec_add(&pvec, page)) {
-                        __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
-                        spin_unlock_irq(&zone->lru_lock);
-                        pgdeactivate += pgmoved;
-                        pgmoved = 0;
-                        if (buffer_heads_over_limit)
-                                pagevec_strip(&pvec);
-                        __pagevec_release(&pvec);
-                        spin_lock_irq(&zone->lru_lock);
-                }
-        }
-        __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
-        pgdeactivate += pgmoved;
-        __count_zone_vm_events(PGREFILL, zone, pgscanned);
-        __count_vm_events(PGDEACTIVATE, pgdeactivate);
         spin_unlock_irq(&zone->lru_lock);
-        if (buffer_heads_over_limit)
-                pagevec_strip(&pvec);
-        pagevec_release(&pvec);
 }
 
 static int inactive_anon_is_low_global(struct zone *zone)
@@ -1348,12 +1352,48 @@ static int inactive_anon_is_low(struct zone *zone, struct scan_control *sc)
         return low;
 }
 
+static int inactive_file_is_low_global(struct zone *zone)
+{
+        unsigned long active, inactive;
+
+        active = zone_page_state(zone, NR_ACTIVE_FILE);
+        inactive = zone_page_state(zone, NR_INACTIVE_FILE);
+
+        return (active > inactive);
+}
+
+/**
+ * inactive_file_is_low - check if file pages need to be deactivated
+ * @zone: zone to check
+ * @sc:   scan control of this context
+ *
+ * When the system is doing streaming IO, memory pressure here
+ * ensures that active file pages get deactivated, until more
+ * than half of the file pages are on the inactive list.
+ *
+ * Once we get to that situation, protect the system's working
+ * set from being evicted by disabling active file page aging.
+ *
+ * This uses a different ratio than the anonymous pages, because
+ * the page cache uses a use-once replacement algorithm.
+ */
+static int inactive_file_is_low(struct zone *zone, struct scan_control *sc)
+{
+        int low;
+
+        if (scanning_global_lru(sc))
+                low = inactive_file_is_low_global(zone);
+        else
+                low = mem_cgroup_inactive_file_is_low(sc->mem_cgroup);
+        return low;
+}
+
 static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
         struct zone *zone, struct scan_control *sc, int priority)
 {
         int file = is_file_lru(lru);
 
-        if (lru == LRU_ACTIVE_FILE) {
+        if (lru == LRU_ACTIVE_FILE && inactive_file_is_low(zone, sc)) {
                 shrink_active_list(nr_to_scan, zone, sc, priority, file);
                 return 0;
         }
@@ -1382,13 +1422,6 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
         unsigned long ap, fp;
         struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
 
-        /* If we have no swap space, do not bother scanning anon pages. */
-        if (!sc->may_swap || (nr_swap_pages <= 0)) {
-                percent[0] = 0;
-                percent[1] = 100;
-                return;
-        }
-
         anon  = zone_nr_pages(zone, sc, LRU_ACTIVE_ANON) +
                 zone_nr_pages(zone, sc, LRU_INACTIVE_ANON);
         file  = zone_nr_pages(zone, sc, LRU_ACTIVE_FILE) +
@@ -1398,7 +1431,7 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
                 free  = zone_page_state(zone, NR_FREE_PAGES);
                 /* If we have very few page cache pages,
                    force-scan anon pages. */
-                if (unlikely(file + free <= zone->pages_high)) {
+                if (unlikely(file + free <= high_wmark_pages(zone))) {
                         percent[0] = 100;
                         percent[1] = 0;
                         return;
@@ -1453,6 +1486,26 @@ static void get_scan_ratio(struct zone *zone, struct scan_control *sc,
         percent[1] = 100 - percent[0];
 }
 
+/*
+ * 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 swap_cluster_max)
+{
+        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;
+}
 
 /*
  * This is a basic per-zone page freer.  Used by both kswapd and direct reclaim.
@@ -1466,26 +1519,30 @@ static void shrink_zone(int priority, struct zone *zone,
         enum lru_list l;
         unsigned long nr_reclaimed = sc->nr_reclaimed;
         unsigned long swap_cluster_max = sc->swap_cluster_max;
+        int noswap = 0;
 
-        get_scan_ratio(zone, sc, percent);
+        /* If we have no swap space, do not bother scanning anon pages. */
+        if (!sc->may_swap || (nr_swap_pages <= 0)) {
+                noswap = 1;
+                percent[0] = 0;
+                percent[1] = 100;
+        } else
+                get_scan_ratio(zone, sc, percent);
 
         for_each_evictable_lru(l) {
                 int file = is_file_lru(l);
                 unsigned long scan;
 
                 scan = zone_nr_pages(zone, sc, l);
-                if (priority) {
+                if (priority || noswap) {
                         scan >>= priority;
                         scan = (scan * percent[file]) / 100;
                 }
-                if (scanning_global_lru(sc)) {
-                        zone->lru[l].nr_scan += scan;
-                        nr[l] = zone->lru[l].nr_scan;
-                        if (nr[l] >= swap_cluster_max)
-                                zone->lru[l].nr_scan = 0;
-                        else
-                                nr[l] = 0;
-                } else
+                if (scanning_global_lru(sc))
+                        nr[l] = nr_scan_try_batch(scan,
+                                                  &zone->lru[l].nr_saved_scan,
+                                                  swap_cluster_max);
+                else
                         nr[l] = scan;
         }
 
@@ -1519,7 +1576,7 @@ static void shrink_zone(int priority, struct zone *zone,
          * Even if we did not try to evict anon pages at all, we want to
          * rebalance the anon lru active/inactive ratio.
          */
-        if (inactive_anon_is_low(zone, sc))
+        if (inactive_anon_is_low(zone, sc) && nr_swap_pages > 0)
                 shrink_active_list(SWAP_CLUSTER_MAX, zone, sc, priority, 0);
 
         throttle_vm_writeout(sc->gfp_mask);
@@ -1530,11 +1587,13 @@ static void shrink_zone(int priority, struct zone *zone,
  * try to reclaim pages from zones which will satisfy the caller's allocation
  * request.
  *
- * We reclaim from a zone even if that zone is over pages_high.  Because:
+ * We reclaim from a zone even if that zone is over high_wmark_pages(zone).
+ * Because:
  * a) The caller may be trying to free *extra* pages to satisfy a higher-order
  *    allocation or
- * b) The zones may be over pages_high but they must go *over* pages_high to
- *    satisfy the `incremental min' zone defense algorithm.
+ * b) The target zone may be at high_wmark_pages(zone) but the lower zones
+ *    must go *over* high_wmark_pages(zone) to satisfy the `incremental min'
+ *    zone defense algorithm.
  *
  * If a zone is deemed to be full of pinned pages then just give it a light
  * scan then give up on it.
@@ -1740,7 +1799,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
 
 /*
  * For kswapd, balance_pgdat() will work across all this node's zones until
- * they are all at pages_high.
+ * they are all at high_wmark_pages(zone).
  *
  * Returns the number of pages which were actually freed.
  *
@@ -1753,11 +1812,11 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
  * the zone for when the problem goes away.
  *
  * kswapd scans the zones in the highmem->normal->dma direction.  It skips
- * zones which have free_pages > pages_high, but once a zone is found to have
- * free_pages <= pages_high, we scan that zone and the lower zones regardless
- * of the number of free pages in the lower zones.  This interoperates with
- * the page allocator fallback scheme to ensure that aging of pages is balanced
- * across the zones.
+ * zones which have free_pages > high_wmark_pages(zone), but once a zone is
+ * found to have free_pages <= high_wmark_pages(zone), we scan that zone and the
+ * lower zones regardless of the number of free pages in the lower zones. This
+ * interoperates with the page allocator fallback scheme to ensure that aging
+ * of pages is balanced across the zones.
  */
 static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
 {
@@ -1778,7 +1837,8 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order)
         };
         /*
          * temp_priority is used to remember the scanning priority at which
-         * this zone was successfully refilled to free_pages == pages_high.
+         * this zone was successfully refilled to
+         * free_pages == high_wmark_pages(zone).
          */
         int temp_priority[MAX_NR_ZONES];
 
@@ -1823,8 +1883,8 @@ loop_again:
                                 shrink_active_list(SWAP_CLUSTER_MAX, zone,
                                                         &sc, priority, 0);
 
-                        if (!zone_watermark_ok(zone, order, zone->pages_high,
-                                               0, 0)) {
+                        if (!zone_watermark_ok(zone, order,
+                                        high_wmark_pages(zone), 0, 0)) {
                                 end_zone = i;
                                 break;
                         }
@@ -1858,8 +1918,8 @@ loop_again:
                                         priority != DEF_PRIORITY)
                                 continue;
 
-                        if (!zone_watermark_ok(zone, order, zone->pages_high,
-                                               end_zone, 0))
+                        if (!zone_watermark_ok(zone, order,
+                                        high_wmark_pages(zone), end_zone, 0))
                                 all_zones_ok = 0;
                         temp_priority[i] = priority;
                         sc.nr_scanned = 0;
@@ -1868,8 +1928,8 @@ loop_again:
                          * We put equal pressure on every zone, unless one
                          * zone has way too many pages free already.
                          */
-                        if (!zone_watermark_ok(zone, order, 8*zone->pages_high,
-                                                end_zone, 0))
+                        if (!zone_watermark_ok(zone, order,
+                                        8*high_wmark_pages(zone), end_zone, 0))
                                 shrink_zone(priority, zone, &sc);
                         reclaim_state->reclaimed_slab = 0;
                         nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
@@ -2035,7 +2095,7 @@ void wakeup_kswapd(struct zone *zone, int order)
                 return;
 
         pgdat = zone->zone_pgdat;
-        if (zone_watermark_ok(zone, order, zone->pages_low, 0, 0))
+        if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0))
                 return;
         if (pgdat->kswapd_max_order < order)
                 pgdat->kswapd_max_order = order;
@@ -2054,7 +2114,7 @@ unsigned long global_lru_pages(void)
                 + global_page_state(NR_INACTIVE_FILE);
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_HIBERNATION
 /*
  * Helper function for shrink_all_memory().  Tries to reclaim 'nr_pages' pages
  * from LRU lists system-wide, for given pass and priority.
@@ -2082,11 +2142,11 @@ static void shrink_all_zones(unsigned long nr_pages, int prio,
                                                 l == LRU_ACTIVE_FILE))
                                 continue;
 
-                        zone->lru[l].nr_scan += (lru_pages >> prio) + 1;
-                        if (zone->lru[l].nr_scan >= nr_pages || pass > 3) {
+                        zone->lru[l].nr_saved_scan += (lru_pages >> prio) + 1;
+                        if (zone->lru[l].nr_saved_scan >= nr_pages || pass > 3) {
                                 unsigned long nr_to_scan;
 
-                                zone->lru[l].nr_scan = 0;
+                                zone->lru[l].nr_saved_scan = 0;
                                 nr_to_scan = min(nr_pages, lru_pages);
                                 nr_reclaimed += shrink_list(l, nr_to_scan, zone,
                                                                 sc, prio);
@@ -2194,7 +2254,7 @@ out:
 
         return sc.nr_reclaimed;
 }
-#endif
+#endif /* CONFIG_HIBERNATION */
 
 /* It's optimal to keep kswapds on the same CPUs as their memory, but
    not required for correctness.  So if the last cpu in a node goes
@@ -2288,6 +2348,48 @@ int sysctl_min_unmapped_ratio = 1;
  */
 int sysctl_min_slab_ratio = 5;
 
+static inline unsigned long zone_unmapped_file_pages(struct zone *zone)
+{
+        unsigned long file_mapped = zone_page_state(zone, NR_FILE_MAPPED);
+        unsigned long file_lru = zone_page_state(zone, NR_INACTIVE_FILE) +
+                zone_page_state(zone, NR_ACTIVE_FILE);
+
+        /*
+         * It's possible for there to be more file mapped pages than
+         * accounted for by the pages on the file LRU lists because
+         * tmpfs pages accounted for as ANON can also be FILE_MAPPED
+         */
+        return (file_lru > file_mapped) ? (file_lru - file_mapped) : 0;
+}
+
+/* Work out how many page cache pages we can reclaim in this reclaim_mode */
+static long zone_pagecache_reclaimable(struct zone *zone)
+{
+        long nr_pagecache_reclaimable;
+        long delta = 0;
+
+        /*
+         * If RECLAIM_SWAP is set, then all file pages are considered
+         * potentially reclaimable. Otherwise, we have to worry about
+         * pages like swapcache and zone_unmapped_file_pages() provides
+         * a better estimate
+         */
+        if (zone_reclaim_mode & RECLAIM_SWAP)
+                nr_pagecache_reclaimable = zone_page_state(zone, NR_FILE_PAGES);
+        else
+                nr_pagecache_reclaimable = zone_unmapped_file_pages(zone);
+
+        /* If we can't clean pages, remove dirty pages from consideration */
+        if (!(zone_reclaim_mode & RECLAIM_WRITE))
+                delta += zone_page_state(zone, NR_FILE_DIRTY);
+
+        /* Watch for any possible underflows due to delta */
+        if (unlikely(delta > nr_pagecache_reclaimable))
+                delta = nr_pagecache_reclaimable;
+
+        return nr_pagecache_reclaimable - delta;
+}
+
 /*
  * Try to free up some pages from this zone through reclaim.
  */
@@ -2322,9 +2424,7 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
         reclaim_state.reclaimed_slab = 0;
         p->reclaim_state = &reclaim_state;
 
-        if (zone_page_state(zone, NR_FILE_PAGES) -
-                zone_page_state(zone, NR_FILE_MAPPED) >
-                zone->min_unmapped_pages) {
+        if (zone_pagecache_reclaimable(zone) > zone->min_unmapped_pages) {
                 /*
                  * Free memory by calling shrink zone with increasing
                  * priorities until we have enough memory freed.
@@ -2382,20 +2482,18 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
          * if less than a specified percentage of the zone is used by
          * unmapped file backed pages.
          */
-        if (zone_page_state(zone, NR_FILE_PAGES) -
-            zone_page_state(zone, NR_FILE_MAPPED) <= zone->min_unmapped_pages
-            && zone_page_state(zone, NR_SLAB_RECLAIMABLE)
-                        <= zone->min_slab_pages)
-                return 0;
+        if (zone_pagecache_reclaimable(zone) <= zone->min_unmapped_pages &&
+            zone_page_state(zone, NR_SLAB_RECLAIMABLE) <= zone->min_slab_pages)
+                return ZONE_RECLAIM_FULL;
 
         if (zone_is_all_unreclaimable(zone))
-                return 0;
+                return ZONE_RECLAIM_FULL;
 
         /*
          * Do not scan if the allocation should not be delayed.
          */
         if (!(gfp_mask & __GFP_WAIT) || (current->flags & PF_MEMALLOC))
-                        return 0;
+                return ZONE_RECLAIM_NOSCAN;
 
         /*
          * Only run zone reclaim on the local zone or on zones that do not
@@ -2405,18 +2503,21 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
          */
         node_id = zone_to_nid(zone);
         if (node_state(node_id, N_CPU) && node_id != numa_node_id())
-                return 0;
+                return ZONE_RECLAIM_NOSCAN;
 
         if (zone_test_and_set_flag(zone, ZONE_RECLAIM_LOCKED))
-                return 0;
+                return ZONE_RECLAIM_NOSCAN;
+
         ret = __zone_reclaim(zone, gfp_mask, order);
         zone_clear_flag(zone, ZONE_RECLAIM_LOCKED);
 
+        if (!ret)
+                count_vm_event(PGSCAN_ZONE_RECLAIM_FAILED);
+
         return ret;
 }
 #endif
 
-#ifdef CONFIG_UNEVICTABLE_LRU
 /*
  * page_evictable - test whether a page is evictable
  * @page: the page to test
@@ -2663,4 +2764,3 @@ void scan_unevictable_unregister_node(struct node *node)
         sysdev_remove_file(&node->sysdev, &attr_scan_unevictable_pages);
 }
 
-#endif