5 files changed, 26 insertions, 3 deletions

diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 391dd64363e7..44518c023949 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -28,6 +28,7 @@ Currently, these files are in /proc/sys/vm:
 - block_dump
 - drop-caches
 - zone_reclaim_mode
+- zone_reclaim_interval
 
 ==============================================================
 
@@ -137,4 +138,15 @@ of memory should be used for caching files from disk.
 
 It may be beneficial to switch this on if one wants to do zone
 reclaim regardless of the numa distances in the system.
+================================================================
+
+zone_reclaim_interval:
+
+The time allowed for off node allocations after zone reclaim
+has failed to reclaim enough pages to allow a local allocation.
+
+Time is set in seconds and set by default to 30 seconds.
+
+Reduce the interval if undesired off node allocations occur. However, too
+frequent scans will have a negative impact onoff node allocation performance.
 
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 4a99e4a7fbf3..e53fef7051e6 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -178,6 +178,7 @@ extern int vm_swappiness;
 
 #ifdef CONFIG_NUMA
 extern int zone_reclaim_mode;
+extern int zone_reclaim_interval;
 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
 #else
 #define zone_reclaim_mode 0
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 8352a7ce5895..32a4139c4ad8 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -182,7 +182,8 @@ enum
         VM_SWAP_TOKEN_TIMEOUT=28, /* default time for token time out */
         VM_DROP_PAGECACHE=29,   /* int: nuke lots of pagecache */
         VM_PERCPU_PAGELIST_FRACTION=30,/* int: fraction of pages in each percpu_pagelist */
-        VM_ZONE_RECLAIM_MODE=31,/* reclaim local zone memory before going off node */
+        VM_ZONE_RECLAIM_MODE=31, /* reclaim local zone memory before going off node */
+        VM_ZONE_RECLAIM_INTERVAL=32, /* time period to wait after reclaim failure */
 };
 
 
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index c74f03bc0144..71dd6f62efec 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -881,6 +881,15 @@ static ctl_table vm_table[] = {
                 .strategy       = &sysctl_intvec,
                 .extra1         = &zero,
         },
+        {
+                .ctl_name       = VM_ZONE_RECLAIM_INTERVAL,
+                .procname       = "zone_reclaim_interval",
+                .data           = &zone_reclaim_interval,
+                .maxlen         = sizeof(zone_reclaim_interval),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec_jiffies,
+                .strategy       = &sysctl_jiffies,
+        },
 #endif
         { .ctl_name = 0 }
 };
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f8b94ea6f722..8760a4abfa1f 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1595,7 +1595,7 @@ int zone_reclaim_mode __read_mostly;
 /*
  * Mininum time between zone reclaim scans
  */
-#define ZONE_RECLAIM_INTERVAL 30*HZ
+int zone_reclaim_interval __read_mostly = 30*HZ;
 
 /*
  * Priority for ZONE_RECLAIM. This determines the fraction of pages
@@ -1617,7 +1617,7 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
         int node_id;
 
         if (time_before(jiffies,
-                zone->last_unsuccessful_zone_reclaim + ZONE_RECLAIM_INTERVAL))
+                zone->last_unsuccessful_zone_reclaim + zone_reclaim_interval))
                         return 0;
 
         if (!(gfp_mask & __GFP_WAIT) ||