14 files changed, 168 insertions, 127 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index f4e516e9c37c..f0fb9124e410 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -189,7 +189,7 @@ config COMPACTION
 config MIGRATION
         bool "Page migration"
         def_bool y
-        depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE
+        depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION
         help
           Allows the migration of the physical location of pages of processes
           while the virtual addresses are not changed. This is useful in
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index eaa4a5bbe063..65d420499a61 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -30,6 +30,7 @@ EXPORT_SYMBOL_GPL(default_backing_dev_info);
 
 struct backing_dev_info noop_backing_dev_info = {
         .name           = "noop",
+        .capabilities   = BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
 EXPORT_SYMBOL_GPL(noop_backing_dev_info);
 
@@ -243,6 +244,7 @@ static int __init default_bdi_init(void)
         err = bdi_init(&default_backing_dev_info);
         if (!err)
                 bdi_register(&default_backing_dev_info, NULL, "default");
+        err = bdi_init(&noop_backing_dev_info);
 
         return err;
 }
@@ -445,8 +447,8 @@ static int bdi_forker_thread(void *ptr)
                 switch (action) {
                 case FORK_THREAD:
                         __set_current_state(TASK_RUNNING);
-                        task = kthread_run(bdi_writeback_thread, &bdi->wb, "flush-%s",
-                                           dev_name(bdi->dev));
+                        task = kthread_create(bdi_writeback_thread, &bdi->wb,
+                                              "flush-%s", dev_name(bdi->dev));
                         if (IS_ERR(task)) {
                                 /*
                                  * If thread creation fails, force writeout of
@@ -457,10 +459,13 @@ static int bdi_forker_thread(void *ptr)
                                 /*
                                  * The spinlock makes sure we do not lose
                                  * wake-ups when racing with 'bdi_queue_work()'.
+                                 * And as soon as the bdi thread is visible, we
+                                 * can start it.
                                  */
                                 spin_lock_bh(&bdi->wb_lock);
                                 bdi->wb.task = task;
                                 spin_unlock_bh(&bdi->wb_lock);
+                                wake_up_process(task);
                         }
                         break;
 
diff --git a/mm/bounce.c b/mm/bounce.c
index 13b6dad1eed2..1481de68184b 100644
--- a/mm/bounce.c
+++ b/mm/bounce.c
@@ -116,8 +116,8 @@ static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
                  */
                 vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;
 
-                flush_dcache_page(tovec->bv_page);
                 bounce_copy_vec(tovec, vfrom);
+                flush_dcache_page(tovec->bv_page);
         }
 }
 
diff --git a/mm/compaction.c b/mm/compaction.c
index 94cce51b0b35..4d709ee59013 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -214,15 +214,16 @@ static void acct_isolated(struct zone *zone, struct compact_control *cc)
 /* Similar to reclaim, but different enough that they don't share logic */
 static bool too_many_isolated(struct zone *zone)
 {
-
-        unsigned long inactive, isolated;
+        unsigned long active, inactive, isolated;
 
         inactive = zone_page_state(zone, NR_INACTIVE_FILE) +
                                         zone_page_state(zone, NR_INACTIVE_ANON);
+        active = zone_page_state(zone, NR_ACTIVE_FILE) +
+                                        zone_page_state(zone, NR_ACTIVE_ANON);
         isolated = zone_page_state(zone, NR_ISOLATED_FILE) +
                                         zone_page_state(zone, NR_ISOLATED_ANON);
 
-        return isolated > inactive;
+        return isolated > (inactive + active) / 2;
 }
 
 /*
diff --git a/mm/ksm.c b/mm/ksm.c
index e2ae00458320..b1873cf03ed9 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1504,8 +1504,6 @@ struct page *ksm_does_need_to_copy(struct page *page,
 {
         struct page *new_page;
 
-        unlock_page(page);      /* any racers will COW it, not modify it */
-
         new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
         if (new_page) {
                 copy_user_highpage(new_page, page, address, vma);
@@ -1521,7 +1519,6 @@ struct page *ksm_does_need_to_copy(struct page *page,
                         add_page_to_unevictable_list(new_page);
         }
 
-        page_cache_release(page);
         return new_page;
 }
 
diff --git a/mm/memory.c b/mm/memory.c
index 6b2ab1051851..0e18b4d649ec 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2623,7 +2623,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
                 unsigned int flags, pte_t orig_pte)
 {
         spinlock_t *ptl;
-        struct page *page;
+        struct page *page, *swapcache = NULL;
         swp_entry_t entry;
         pte_t pte;
         struct mem_cgroup *ptr = NULL;
@@ -2679,10 +2679,25 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
         lock_page(page);
         delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
 
-        page = ksm_might_need_to_copy(page, vma, address);
-        if (!page) {
-                ret = VM_FAULT_OOM;
-                goto out;
+        /*
+         * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
+         * release the swapcache from under us.  The page pin, and pte_same
+         * test below, are not enough to exclude that.  Even if it is still
+         * swapcache, we need to check that the page's swap has not changed.
+         */
+        if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
+                goto out_page;
+
+        if (ksm_might_need_to_copy(page, vma, address)) {
+                swapcache = page;
+                page = ksm_does_need_to_copy(page, vma, address);
+
+                if (unlikely(!page)) {
+                        ret = VM_FAULT_OOM;
+                        page = swapcache;
+                        swapcache = NULL;
+                        goto out_page;
+                }
         }
 
         if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
@@ -2735,6 +2750,18 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
         if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
                 try_to_free_swap(page);
         unlock_page(page);
+        if (swapcache) {
+                /*
+                 * Hold the lock to avoid the swap entry to be reused
+                 * until we take the PT lock for the pte_same() check
+                 * (to avoid false positives from pte_same). For
+                 * further safety release the lock after the swap_free
+                 * so that the swap count won't change under a
+                 * parallel locked swapcache.
+                 */
+                unlock_page(swapcache);
+                page_cache_release(swapcache);
+        }
 
         if (flags & FAULT_FLAG_WRITE) {
                 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
@@ -2756,6 +2783,10 @@ out_page:
         unlock_page(page);
 out_release:
         page_cache_release(page);
+        if (swapcache) {
+                unlock_page(swapcache);
+                page_cache_release(swapcache);
+        }
         return ret;
 }
 
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a4cfcdc00455..dd186c1a5d53 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -584,19 +584,19 @@ static inline int pageblock_free(struct page *page)
 /* Return the start of the next active pageblock after a given page */
 static struct page *next_active_pageblock(struct page *page)
 {
-        int pageblocks_stride;
-
         /* Ensure the starting page is pageblock-aligned */
         BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
 
-        /* Move forward by at least 1 * pageblock_nr_pages */
-        pageblocks_stride = 1;
-
         /* If the entire pageblock is free, move to the end of free page */
-        if (pageblock_free(page))
-                pageblocks_stride += page_order(page) - pageblock_order;
+        if (pageblock_free(page)) {
+                int order;
+                /* be careful. we don't have locks, page_order can be changed.*/
+                order = page_order(page);
+                if ((order < MAX_ORDER) && (order >= pageblock_order))
+                        return page + (1 << order);
+        }
 
-        return page + (pageblocks_stride * pageblock_nr_pages);
+        return page + pageblock_nr_pages;
 }
 
 /* Checks if this range of memory is likely to be hot-removable. */
diff --git a/mm/mlock.c b/mm/mlock.c
index cbae7c5b9568..b70919ce4f72 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -135,12 +135,6 @@ void munlock_vma_page(struct page *page)
         }
 }
 
-/* Is the vma a continuation of the stack vma above it? */
-static inline int vma_stack_continue(struct vm_area_struct *vma, unsigned long addr)
-{
-        return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
-}
-
 static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
 {
         return (vma->vm_flags & VM_GROWSDOWN) &&
diff --git a/mm/mmzone.c b/mm/mmzone.c
index f5b7d1760213..e35bfb82c855 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -87,3 +87,24 @@ int memmap_valid_within(unsigned long pfn,
         return 1;
 }
 #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
+
+#ifdef CONFIG_SMP
+/* Called when a more accurate view of NR_FREE_PAGES is needed */
+unsigned long zone_nr_free_pages(struct zone *zone)
+{
+        unsigned long nr_free_pages = zone_page_state(zone, NR_FREE_PAGES);
+
+        /*
+         * While kswapd is awake, it is considered the zone is under some
+         * memory pressure. Under pressure, there is a risk that
+         * per-cpu-counter-drift will allow the min watermark to be breached
+         * potentially causing a live-lock. While kswapd is awake and
+         * free pages are low, get a better estimate for free pages
+         */
+        if (nr_free_pages < zone->percpu_drift_mark &&
+                        !waitqueue_active(&zone->zone_pgdat->kswapd_wait))
+                return zone_page_state_snapshot(zone, NR_FREE_PAGES);
+
+        return nr_free_pages;
+}
+#endif /* CONFIG_SMP */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a9649f4b261e..a8cfa9cc6e86 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -588,13 +588,13 @@ static void free_pcppages_bulk(struct zone *zone, int count,
 {
         int migratetype = 0;
         int batch_free = 0;
+        int to_free = count;
 
         spin_lock(&zone->lock);
         zone->all_unreclaimable = 0;
         zone->pages_scanned = 0;
 
-        __mod_zone_page_state(zone, NR_FREE_PAGES, count);
-        while (count) {
+        while (to_free) {
                 struct page *page;
                 struct list_head *list;
 
@@ -619,8 +619,9 @@ static void free_pcppages_bulk(struct zone *zone, int count,
                         /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */
                         __free_one_page(page, zone, 0, page_private(page));
                         trace_mm_page_pcpu_drain(page, 0, page_private(page));
-                } while (--count && --batch_free && !list_empty(list));
+                } while (--to_free && --batch_free && !list_empty(list));
         }
+        __mod_zone_page_state(zone, NR_FREE_PAGES, count);
         spin_unlock(&zone->lock);
 }
 
@@ -631,8 +632,8 @@ static void free_one_page(struct zone *zone, struct page *page, int order,
         zone->all_unreclaimable = 0;
         zone->pages_scanned = 0;
 
-        __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
         __free_one_page(page, zone, order, migratetype);
+        __mod_zone_page_state(zone, NR_FREE_PAGES, 1 << order);
         spin_unlock(&zone->lock);
 }
 
@@ -1461,7 +1462,7 @@ int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
 {
         /* free_pages my go negative - that's OK */
         long min = mark;
-        long free_pages = zone_page_state(z, NR_FREE_PAGES) - (1 << order) + 1;
+        long free_pages = zone_nr_free_pages(z) - (1 << order) + 1;
         int o;
 
         if (alloc_flags & ALLOC_HIGH)
@@ -1846,6 +1847,7 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
         struct page *page = NULL;
         struct reclaim_state reclaim_state;
         struct task_struct *p = current;
+        bool drained = false;
 
         cond_resched();
 
@@ -1864,14 +1866,25 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
 
         cond_resched();
 
-        if (order != 0)
-                drain_all_pages();
+        if (unlikely(!(*did_some_progress)))
+                return NULL;
 
-        if (likely(*did_some_progress))
-                page = get_page_from_freelist(gfp_mask, nodemask, order,
+retry:
+        page = get_page_from_freelist(gfp_mask, nodemask, order,
                                         zonelist, high_zoneidx,
                                         alloc_flags, preferred_zone,
                                         migratetype);
+
+        /*
+         * If an allocation failed after direct reclaim, it could be because
+         * pages are pinned on the per-cpu lists. Drain them and try again
+         */
+        if (!page && !drained) {
+                drain_all_pages();
+                drained = true;
+                goto retry;
+        }
+
         return page;
 }
 
@@ -2423,7 +2436,7 @@ void show_free_areas(void)
                         " all_unreclaimable? %s"
                         "\n",
                         zone->name,
-                        K(zone_page_state(zone, NR_FREE_PAGES)),
+                        K(zone_nr_free_pages(zone)),
                         K(min_wmark_pages(zone)),
                         K(low_wmark_pages(zone)),
                         K(high_wmark_pages(zone)),
diff --git a/mm/percpu.c b/mm/percpu.c
index e61dc2cc5873..58c572b18b07 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -393,7 +393,9 @@ static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
                 goto out_unlock;
 
         old_size = chunk->map_alloc * sizeof(chunk->map[0]);
-        memcpy(new, chunk->map, old_size);
+        old = chunk->map;
+
+        memcpy(new, old, old_size);
 
         chunk->map_alloc = new_alloc;
         chunk->map = new;
@@ -1162,7 +1164,7 @@ static struct pcpu_alloc_info * __init pcpu_build_alloc_info(
                 }
 
                 /*
-                 * Don't accept if wastage is over 25%.  The
+                 * Don't accept if wastage is over 1/3.  The
                  * greater-than comparison ensures upa==1 always
                  * passes the following check.
                  */
diff --git a/mm/percpu_up.c b/mm/percpu_up.c
index c4351c7f57d2..db884fae5721 100644
--- a/mm/percpu_up.c
+++ b/mm/percpu_up.c
@@ -14,13 +14,13 @@ void __percpu *__alloc_percpu(size_t size, size_t align)
          * percpu sections on SMP for which this path isn't used.
          */
         WARN_ON_ONCE(align > SMP_CACHE_BYTES);
-        return kzalloc(size, GFP_KERNEL);
+        return (void __percpu __force *)kzalloc(size, GFP_KERNEL);
 }
 EXPORT_SYMBOL_GPL(__alloc_percpu);
 
 void free_percpu(void __percpu *p)
 {
-        kfree(p);
+        kfree(this_cpu_ptr(p));
 }
 EXPORT_SYMBOL_GPL(free_percpu);
 
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 1f3f9c59a73a..7c703ff2f36f 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -47,8 +47,6 @@ long nr_swap_pages;
 long total_swap_pages;
 static int least_priority;
 
-static bool swap_for_hibernation;
-
 static const char Bad_file[] = "Bad swap file entry ";
 static const char Unused_file[] = "Unused swap file entry ";
 static const char Bad_offset[] = "Bad swap offset entry ";
@@ -141,8 +139,7 @@ static int discard_swap(struct swap_info_struct *si)
         nr_blocks = ((sector_t)se->nr_pages - 1) << (PAGE_SHIFT - 9);
         if (nr_blocks) {
                 err = blkdev_issue_discard(si->bdev, start_block,
-                                nr_blocks, GFP_KERNEL,
-                                BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
+                                nr_blocks, GFP_KERNEL, BLKDEV_IFL_WAIT);
                 if (err)
                         return err;
                 cond_resched();
@@ -153,8 +150,7 @@ static int discard_swap(struct swap_info_struct *si)
                 nr_blocks = (sector_t)se->nr_pages << (PAGE_SHIFT - 9);
 
                 err = blkdev_issue_discard(si->bdev, start_block,
-                                nr_blocks, GFP_KERNEL,
-                                BLKDEV_IFL_WAIT | BLKDEV_IFL_BARRIER);
+                                nr_blocks, GFP_KERNEL, BLKDEV_IFL_WAIT);
                 if (err)
                         break;
 
@@ -193,8 +189,7 @@ static void discard_swap_cluster(struct swap_info_struct *si,
                         start_block <<= PAGE_SHIFT - 9;
                         nr_blocks <<= PAGE_SHIFT - 9;
                         if (blkdev_issue_discard(si->bdev, start_block,
-                                    nr_blocks, GFP_NOIO, BLKDEV_IFL_WAIT |
-                                                        BLKDEV_IFL_BARRIER))
+                                    nr_blocks, GFP_NOIO, BLKDEV_IFL_WAIT))
                                 break;
                 }
 
@@ -320,10 +315,8 @@ checks:
         if (offset > si->highest_bit)
                 scan_base = offset = si->lowest_bit;
 
-        /* reuse swap entry of cache-only swap if not hibernation. */
-        if (vm_swap_full()
-                && usage == SWAP_HAS_CACHE
-                && si->swap_map[offset] == SWAP_HAS_CACHE) {
+        /* reuse swap entry of cache-only swap if not busy. */
+        if (vm_swap_full() && si->swap_map[offset] == SWAP_HAS_CACHE) {
                 int swap_was_freed;
                 spin_unlock(&swap_lock);
                 swap_was_freed = __try_to_reclaim_swap(si, offset);
@@ -453,8 +446,6 @@ swp_entry_t get_swap_page(void)
         spin_lock(&swap_lock);
         if (nr_swap_pages <= 0)
                 goto noswap;
-        if (swap_for_hibernation)
-                goto noswap;
         nr_swap_pages--;
 
         for (type = swap_list.next; type >= 0 && wrapped < 2; type = next) {
@@ -487,6 +478,28 @@ noswap:
         return (swp_entry_t) {0};
 }
 
+/* The only caller of this function is now susupend routine */
+swp_entry_t get_swap_page_of_type(int type)
+{
+        struct swap_info_struct *si;
+        pgoff_t offset;
+
+        spin_lock(&swap_lock);
+        si = swap_info[type];
+        if (si && (si->flags & SWP_WRITEOK)) {
+                nr_swap_pages--;
+                /* This is called for allocating swap entry, not cache */
+                offset = scan_swap_map(si, 1);
+                if (offset) {
+                        spin_unlock(&swap_lock);
+                        return swp_entry(type, offset);
+                }
+                nr_swap_pages++;
+        }
+        spin_unlock(&swap_lock);
+        return (swp_entry_t) {0};
+}
+
 static struct swap_info_struct *swap_info_get(swp_entry_t entry)
 {
         struct swap_info_struct *p;
@@ -670,6 +683,24 @@ int try_to_free_swap(struct page *page)
         if (page_swapcount(page))
                 return 0;
 
+        /*
+         * Once hibernation has begun to create its image of memory,
+         * there's a danger that one of the calls to try_to_free_swap()
+         * - most probably a call from __try_to_reclaim_swap() while
+         * hibernation is allocating its own swap pages for the image,
+         * but conceivably even a call from memory reclaim - will free
+         * the swap from a page which has already been recorded in the
+         * image as a clean swapcache page, and then reuse its swap for
+         * another page of the image.  On waking from hibernation, the
+         * original page might be freed under memory pressure, then
+         * later read back in from swap, now with the wrong data.
+         *
+         * Hibernation clears bits from gfp_allowed_mask to prevent
+         * memory reclaim from writing to disk, so check that here.
+         */
+        if (!(gfp_allowed_mask & __GFP_IO))
+                return 0;
+
         delete_from_swap_cache(page);
         SetPageDirty(page);
         return 1;
@@ -746,74 +777,6 @@ int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep)
 #endif
 
 #ifdef CONFIG_HIBERNATION
-
-static pgoff_t hibernation_offset[MAX_SWAPFILES];
-/*
- * Once hibernation starts to use swap, we freeze swap_map[]. Otherwise,
- * saved swap_map[] image to the disk will be an incomplete because it's
- * changing without synchronization with hibernation snap shot.
- * At resume, we just make swap_for_hibernation=false. We can forget
- * used maps easily.
- */
-void hibernation_freeze_swap(void)
-{
-        int i;
-
-        spin_lock(&swap_lock);
-
-        printk(KERN_INFO "PM: Freeze Swap\n");
-        swap_for_hibernation = true;
-        for (i = 0; i < MAX_SWAPFILES; i++)
-                hibernation_offset[i] = 1;
-        spin_unlock(&swap_lock);
-}
-
-void hibernation_thaw_swap(void)
-{
-        spin_lock(&swap_lock);
-        if (swap_for_hibernation) {
-                printk(KERN_INFO "PM: Thaw Swap\n");
-                swap_for_hibernation = false;
-        }
-        spin_unlock(&swap_lock);
-}
-
-/*
- * Because updateing swap_map[] can make not-saved-status-change,
- * we use our own easy allocator.
- * Please see kernel/power/swap.c, Used swaps are recorded into
- * RB-tree.
- */
-swp_entry_t get_swap_for_hibernation(int type)
-{
-        pgoff_t off;
-        swp_entry_t val = {0};
-        struct swap_info_struct *si;
-
-        spin_lock(&swap_lock);
-
-        si = swap_info[type];
-        if (!si || !(si->flags & SWP_WRITEOK))
-                goto done;
-
-        for (off = hibernation_offset[type]; off < si->max; ++off) {
-                if (!si->swap_map[off])
-                        break;
-        }
-        if (off < si->max) {
-                val = swp_entry(type, off);
-                hibernation_offset[type] = off + 1;
-        }
-done:
-        spin_unlock(&swap_lock);
-        return val;
-}
-
-void swap_free_for_hibernation(swp_entry_t ent)
-{
-        /* Nothing to do */
-}
-
 /*
  * Find the swap type that corresponds to given device (if any).
  *
@@ -2084,7 +2047,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
                         p->flags |= SWP_SOLIDSTATE;
                         p->cluster_next = 1 + (random32() % p->highest_bit);
                 }
-                if (discard_swap(p) == 0)
+                if (discard_swap(p) == 0 && (swap_flags & SWAP_FLAG_DISCARD))
                         p->flags |= SWP_DISCARDABLE;
         }
 
diff --git a/mm/vmstat.c b/mm/vmstat.c
index f389168f9a83..355a9e669aaa 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -138,11 +138,24 @@ static void refresh_zone_stat_thresholds(void)
         int threshold;
 
         for_each_populated_zone(zone) {
+                unsigned long max_drift, tolerate_drift;
+
                 threshold = calculate_threshold(zone);
 
                 for_each_online_cpu(cpu)
                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
                                                         = threshold;
+
+                /*
+                 * Only set percpu_drift_mark if there is a danger that
+                 * NR_FREE_PAGES reports the low watermark is ok when in fact
+                 * the min watermark could be breached by an allocation
+                 */
+                tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
+                max_drift = num_online_cpus() * threshold;
+                if (max_drift > tolerate_drift)
+                        zone->percpu_drift_mark = high_wmark_pages(zone) +
+                                        max_drift;
         }
 }
 
@@ -813,7 +826,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
                    "\n        scanned  %lu"
                    "\n        spanned  %lu"
                    "\n        present  %lu",
-                   zone_page_state(zone, NR_FREE_PAGES),
+                   zone_nr_free_pages(zone),
                    min_wmark_pages(zone),
                    low_wmark_pages(zone),
                    high_wmark_pages(zone),
@@ -998,6 +1011,7 @@ static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
         switch (action) {
         case CPU_ONLINE:
         case CPU_ONLINE_FROZEN:
+                refresh_zone_stat_thresholds();
                 start_cpu_timer(cpu);
                 node_set_state(cpu_to_node(cpu), N_CPU);
                 break;