1 files changed, 61 insertions, 30 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0ada2b2954b0..f7c0fb993fb9 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -267,26 +267,35 @@ static void wb_min_max_ratio(struct bdi_writeback *wb,
  */
 
 /**
- * zone_dirtyable_memory - number of dirtyable pages in a zone
- * @zone: the zone
+ * node_dirtyable_memory - number of dirtyable pages in a node
+ * @pgdat: the node
  *
- * Returns the zone's number of pages potentially available for dirty
- * page cache.  This is the base value for the per-zone dirty limits.
+ * Returns the node's number of pages potentially available for dirty
+ * page cache.  This is the base value for the per-node dirty limits.
  */
-static unsigned long zone_dirtyable_memory(struct zone *zone)
+static unsigned long node_dirtyable_memory(struct pglist_data *pgdat)
 {
-        unsigned long nr_pages;
+        unsigned long nr_pages = 0;
+        int z;
+
+        for (z = 0; z < MAX_NR_ZONES; z++) {
+                struct zone *zone = pgdat->node_zones + z;
+
+                if (!populated_zone(zone))
+                        continue;
+
+                nr_pages += zone_page_state(zone, NR_FREE_PAGES);
+        }
 
-        nr_pages = zone_page_state(zone, NR_FREE_PAGES);
         /*
          * Pages reserved for the kernel should not be considered
          * dirtyable, to prevent a situation where reclaim has to
          * clean pages in order to balance the zones.
          */
-        nr_pages -= min(nr_pages, zone->totalreserve_pages);
+        nr_pages -= min(nr_pages, pgdat->totalreserve_pages);
 
-        nr_pages += node_page_state(zone->zone_pgdat, NR_INACTIVE_FILE);
-        nr_pages += node_page_state(zone->zone_pgdat, NR_ACTIVE_FILE);
+        nr_pages += node_page_state(pgdat, NR_INACTIVE_FILE);
+        nr_pages += node_page_state(pgdat, NR_ACTIVE_FILE);
 
         return nr_pages;
 }
@@ -299,13 +308,24 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
         int i;
 
         for_each_node_state(node, N_HIGH_MEMORY) {
-                for (i = 0; i < MAX_NR_ZONES; i++) {
-                        struct zone *z = &NODE_DATA(node)->node_zones[i];
+                for (i = ZONE_NORMAL + 1; i < MAX_NR_ZONES; i++) {
+                        struct zone *z;
+                        unsigned long dirtyable;
+
+                        if (!is_highmem_idx(i))
+                                continue;
+
+                        z = &NODE_DATA(node)->node_zones[i];
+                        dirtyable = zone_page_state(z, NR_FREE_PAGES) +
+                                zone_page_state(z, NR_ZONE_LRU_FILE);
 
-                        if (is_highmem(z))
-                                x += zone_dirtyable_memory(z);
+                        /* watch for underflows */
+                        dirtyable -= min(dirtyable, high_wmark_pages(z));
+
+                        x += dirtyable;
                 }
         }
+
         /*
          * Unreclaimable memory (kernel memory or anonymous memory
          * without swap) can bring down the dirtyable pages below
@@ -445,23 +465,23 @@ void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty)
 }
 
 /**
- * zone_dirty_limit - maximum number of dirty pages allowed in a zone
- * @zone: the zone
+ * node_dirty_limit - maximum number of dirty pages allowed in a node
+ * @pgdat: the node
  *
- * Returns the maximum number of dirty pages allowed in a zone, based
- * on the zone's dirtyable memory.
+ * Returns the maximum number of dirty pages allowed in a node, based
+ * on the node's dirtyable memory.
  */
-static unsigned long zone_dirty_limit(struct zone *zone)
+static unsigned long node_dirty_limit(struct pglist_data *pgdat)
 {
-        unsigned long zone_memory = zone_dirtyable_memory(zone);
+        unsigned long node_memory = node_dirtyable_memory(pgdat);
         struct task_struct *tsk = current;
         unsigned long dirty;
 
         if (vm_dirty_bytes)
                 dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE) *
-                        zone_memory / global_dirtyable_memory();
+                        node_memory / global_dirtyable_memory();
         else
-                dirty = vm_dirty_ratio * zone_memory / 100;
+                dirty = vm_dirty_ratio * node_memory / 100;
 
         if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk))
                 dirty += dirty / 4;
@@ -470,19 +490,30 @@ static unsigned long zone_dirty_limit(struct zone *zone)
 }
 
 /**
- * zone_dirty_ok - tells whether a zone is within its dirty limits
- * @zone: the zone to check
+ * node_dirty_ok - tells whether a node is within its dirty limits
+ * @pgdat: the node to check
  *
- * Returns %true when the dirty pages in @zone are within the zone's
+ * Returns %true when the dirty pages in @pgdat are within the node's
  * dirty limit, %false if the limit is exceeded.
  */
-bool zone_dirty_ok(struct zone *zone)
+bool node_dirty_ok(struct pglist_data *pgdat)
 {
-        unsigned long limit = zone_dirty_limit(zone);
+        int z;
+        unsigned long limit = node_dirty_limit(pgdat);
+        unsigned long nr_pages = 0;
+
+        for (z = 0; z < MAX_NR_ZONES; z++) {
+                struct zone *zone = pgdat->node_zones + z;
+
+                if (!populated_zone(zone))
+                        continue;
+
+                nr_pages += zone_page_state(zone, NR_FILE_DIRTY);
+                nr_pages += zone_page_state(zone, NR_UNSTABLE_NFS);
+                nr_pages += zone_page_state(zone, NR_WRITEBACK);
+        }
 
-        return zone_page_state(zone, NR_FILE_DIRTY) +
-               zone_page_state(zone, NR_UNSTABLE_NFS) +
-               zone_page_state(zone, NR_WRITEBACK) <= limit;
+        return nr_pages <= limit;
 }
 
 int dirty_background_ratio_handler(struct ctl_table *table, int write,