3 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index dfc2452ccb10..18fed8b67943 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -149,6 +149,8 @@ struct zone {
          * as it fails a watermark_ok() in __alloc_pages?
          */
         int                     reclaim_pages;
+        /* A count of how many reclaimers are scanning this zone */
+        atomic_t                reclaim_in_progress;
 
         /*
          * prev_priority holds the scanning priority for this zone.  It is
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a9da20bc2ed0..2019c1b19254 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1738,6 +1738,7 @@ static void __init free_area_init_core(struct pglist_data *pgdat,
                 zone->nr_scan_inactive = 0;
                 zone->nr_active = 0;
                 zone->nr_inactive = 0;
+                atomic_set(&zone->reclaim_in_progress, -1);
                 if (!size)
                         continue;
 
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7da846960d8a..24da725a30f0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -900,7 +900,9 @@ shrink_caches(struct zone **zones, struct scan_control *sc)
                 if (zone->all_unreclaimable && sc->priority != DEF_PRIORITY)
                         continue;       /* Let kswapd poll it */
 
+                atomic_inc(&zone->reclaim_in_progress);
                 shrink_zone(zone, sc);
+                atomic_dec(&zone->reclaim_in_progress);
         }
 }
  
@@ -1111,7 +1113,9 @@ scan:
                         sc.nr_reclaimed = 0;
                         sc.priority = priority;
                         sc.swap_cluster_max = nr_pages? nr_pages : SWAP_CLUSTER_MAX;
+                        atomic_inc(&zone->reclaim_in_progress);
                         shrink_zone(zone, &sc);
+                        atomic_dec(&zone->reclaim_in_progress);
                         reclaim_state->reclaimed_slab = 0;
                         nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
                                                 lru_pages);
@@ -1354,9 +1358,15 @@ int zone_reclaim(struct zone *zone, unsigned int gfp_mask, unsigned int order)
         else
                 sc.swap_cluster_max = SWAP_CLUSTER_MAX;
 
+        /* Don't reclaim the zone if there are other reclaimers active */
+        if (!atomic_inc_and_test(&zone->reclaim_in_progress))
+                goto out;
+
         shrink_zone(zone, &sc);
         total_reclaimed = sc.nr_reclaimed;
 
+ out:
+        atomic_dec(&zone->reclaim_in_progress);
         return total_reclaimed;
 }