---

yaml
---
r: 19375
b: refs/heads/master
c: 2a16e3f
h: refs/heads/master
i:
  19373: 4a57274
  19371: 56ba5ce
  19367: e7cab23
  19359: c627961
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 1b2ffb7896ad46067f5b9ebf7de1891d74a4cdef
+refs/heads/master: 2a16e3f4b0c408b9e50297d2ec27e295d490267a

trunk/Documentation/sysctl/vm.txt

@@ -137,6 +137,7 @@ This is value ORed together of
 1	= Zone reclaim on
 2	= Zone reclaim writes dirty pages out
 4	= Zone reclaim swaps pages
+8	= Also do a global slab reclaim pass
 
 zone_reclaim_mode is set during bootup to 1 if it is determined that pages
 from remote zones will cause a measurable performance reduction. The
@@ -160,6 +161,11 @@ Allowing regular swap effectively restricts allocations to the local
 node unless explicitly overridden by memory policies or cpuset
 configurations.
 
+It may be advisable to allow slab reclaim if the system makes heavy
+use of files and builds up large slab caches. However, the slab
+shrink operation is global, may take a long time and free slabs
+in all nodes of the system.
+
 ================================================================
 
 zone_reclaim_interval:

trunk/mm/vmscan.c

@@ -1596,6 +1596,7 @@ int zone_reclaim_mode __read_mostly;
 #define RECLAIM_ZONE (1<<0)	/* Run shrink_cache on the zone */
 #define RECLAIM_WRITE (1<<1)	/* Writeout pages during reclaim */
 #define RECLAIM_SWAP (1<<2)	/* Swap pages out during reclaim */
+#define RECLAIM_SLAB (1<<3)	/* Do a global slab shrink if the zone is out of memory */
 
 /*
  * Mininum time between zone reclaim scans
@@ -1666,6 +1667,19 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 
 	} while (sc.nr_reclaimed < nr_pages && sc.priority > 0);
 
+	if (sc.nr_reclaimed < nr_pages && (zone_reclaim_mode & RECLAIM_SLAB)) {
+		/*
+		 * shrink_slab does not currently allow us to determine
+		 * how many pages were freed in the zone. So we just
+		 * shake the slab and then go offnode for a single allocation.
+		 *
+		 * shrink_slab will free memory on all zones and may take
+		 * a long time.
+		 */
+		shrink_slab(sc.nr_scanned, gfp_mask, order);
+		sc.nr_reclaimed = 1;    /* Avoid getting the off node timeout */
+	}
+
 	p->reclaim_state = NULL;
 	current->flags &= ~PF_MEMALLOC;