---

yaml
---
r: 35628
b: refs/heads/master
c: 0ff3849
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 972d1a7b140569084439a81265a0f15b74e924e0
+refs/heads/master: 0ff38490c836dc379ff7ec45b10a15a662f4e5f6

trunk/Documentation/sysctl/vm.txt

@@ -29,6 +29,7 @@ Currently, these files are in /proc/sys/vm:
 - drop-caches
 - zone_reclaim_mode
 - min_unmapped_ratio
+- min_slab_ratio
 - panic_on_oom
 
 ==============================================================
@@ -138,7 +139,6 @@ 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
@@ -162,18 +162,13 @@ 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.
-
 =============================================================
 
 min_unmapped_ratio:
 
 This is available only on NUMA kernels.
 
-A percentage of the file backed pages in each zone.  Zone reclaim will only
+A percentage of the total pages in each zone.  Zone reclaim will only
 occur if more than this percentage of pages are file backed and unmapped.
 This is to insure that a minimal amount of local pages is still available for
 file I/O even if the node is overallocated.
@@ -182,6 +177,24 @@ The default is 1 percent.
 
 =============================================================
 
+min_slab_ratio:
+
+This is available only on NUMA kernels.
+
+A percentage of the total pages in each zone.  On Zone reclaim
+(fallback from the local zone occurs) slabs will be reclaimed if more
+than this percentage of pages in a zone are reclaimable slab pages.
+This insures that the slab growth stays under control even in NUMA
+systems that rarely perform global reclaim.
+
+The default is 5 percent.
+
+Note that slab reclaim is triggered in a per zone / node fashion.
+The process of reclaiming slab memory is currently not node specific
+and may not be fast.
+
+=============================================================
+
 panic_on_oom
 
 This enables or disables panic on out-of-memory feature.  If this is set to 1,

trunk/include/linux/mmzone.h

@@ -171,6 +171,7 @@ struct zone {
 	 * zone reclaim becomes active if more unmapped pages exist.
 	 */
 	unsigned long		min_unmapped_pages;
+	unsigned long		min_slab_pages;
 	struct per_cpu_pageset	*pageset[NR_CPUS];
 #else
 	struct per_cpu_pageset	pageset[NR_CPUS];
@@ -448,6 +449,8 @@ int percpu_pagelist_fraction_sysctl_handler(struct ctl_table *, int, struct file
 					void __user *, size_t *, loff_t *);
 int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *, int,
 			struct file *, void __user *, size_t *, loff_t *);
+int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
+			struct file *, void __user *, size_t *, loff_t *);
 
 #include <linux/topology.h>
 /* Returns the number of the current Node. */

trunk/include/linux/swap.h

@@ -193,6 +193,7 @@ extern long vm_total_pages;
 #ifdef CONFIG_NUMA
 extern int zone_reclaim_mode;
 extern int sysctl_min_unmapped_ratio;
+extern int sysctl_min_slab_ratio;
 extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
 #else
 #define zone_reclaim_mode 0

trunk/include/linux/sysctl.h

@@ -191,6 +191,7 @@ enum
 	VM_MIN_UNMAPPED=32,	/* Set min percent of unmapped pages */
 	VM_PANIC_ON_OOM=33,	/* panic at out-of-memory */
 	VM_VDSO_ENABLED=34,	/* map VDSO into new processes? */
+	VM_MIN_SLAB=35,		 /* Percent pages ignored by zone reclaim */
 };
 
 

trunk/kernel/sysctl.c

@@ -943,6 +943,17 @@ static ctl_table vm_table[] = {
 		.extra1		= &zero,
 		.extra2		= &one_hundred,
 	},
+	{
+		.ctl_name	= VM_MIN_SLAB,
+		.procname	= "min_slab_ratio",
+		.data		= &sysctl_min_slab_ratio,
+		.maxlen		= sizeof(sysctl_min_slab_ratio),
+		.mode		= 0644,
+		.proc_handler	= &sysctl_min_slab_ratio_sysctl_handler,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &zero,
+		.extra2		= &one_hundred,
+	},
 #endif
 #ifdef CONFIG_X86_32
 	{

trunk/mm/page_alloc.c

@@ -2005,6 +2005,7 @@ static void __meminit free_area_init_core(struct pglist_data *pgdat,
 #ifdef CONFIG_NUMA
 		zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
 						/ 100;
+		zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
 #endif
 		zone->name = zone_names[j];
 		spin_lock_init(&zone->lock);
@@ -2318,6 +2319,22 @@ int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
 				sysctl_min_unmapped_ratio) / 100;
 	return 0;
 }
+
+int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
+	struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
+{
+	struct zone *zone;
+	int rc;
+
+	rc = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
+	if (rc)
+		return rc;
+
+	for_each_zone(zone)
+		zone->min_slab_pages = (zone->present_pages *
+				sysctl_min_slab_ratio) / 100;
+	return 0;
+}
 #endif
 
 /*

trunk/mm/vmscan.c

@@ -1527,7 +1527,6 @@ 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 */
 
 /*
  * Priority for ZONE_RECLAIM. This determines the fraction of pages
@@ -1542,6 +1541,12 @@ int zone_reclaim_mode __read_mostly;
  */
 int sysctl_min_unmapped_ratio = 1;
 
+/*
+ * If the number of slab pages in a zone grows beyond this percentage then
+ * slab reclaim needs to occur.
+ */
+int sysctl_min_slab_ratio = 5;
+
 /*
  * Try to free up some pages from this zone through reclaim.
  */
@@ -1573,29 +1578,37 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 	reclaim_state.reclaimed_slab = 0;
 	p->reclaim_state = &reclaim_state;
 
-	/*
-	 * Free memory by calling shrink zone with increasing priorities
-	 * until we have enough memory freed.
-	 */
-	priority = ZONE_RECLAIM_PRIORITY;
-	do {
-		nr_reclaimed += shrink_zone(priority, zone, &sc);
-		priority--;
-	} while (priority >= 0 && nr_reclaimed < nr_pages);
+	if (zone_page_state(zone, NR_FILE_PAGES) -
+		zone_page_state(zone, NR_FILE_MAPPED) >
+		zone->min_unmapped_pages) {
+		/*
+		 * Free memory by calling shrink zone with increasing
+		 * priorities until we have enough memory freed.
+		 */
+		priority = ZONE_RECLAIM_PRIORITY;
+		do {
+			nr_reclaimed += shrink_zone(priority, zone, &sc);
+			priority--;
+		} while (priority >= 0 && nr_reclaimed < nr_pages);
+	}
 
-	if (nr_reclaimed < nr_pages && (zone_reclaim_mode & RECLAIM_SLAB)) {
+	if (zone_page_state(zone, NR_SLAB_RECLAIMABLE) > zone->min_slab_pages) {
 		/*
 		 * shrink_slab() does not currently allow us to determine how
-		 * many pages were freed in this zone. So we just shake the slab
-		 * a bit and then go off node for this particular allocation
-		 * despite possibly having freed enough memory to allocate in
-		 * this zone.  If we freed local memory then the next
-		 * allocations will be local again.
+		 * many pages were freed in this zone. So we take the current
+		 * number of slab pages and shake the slab until it is reduced
+		 * by the same nr_pages that we used for reclaiming unmapped
+		 * pages.
 		 *
-		 * shrink_slab will free memory on all zones and may take
-		 * a long time.
+		 * Note that shrink_slab will free memory on all zones and may
+		 * take a long time.
 		 */
-		shrink_slab(sc.nr_scanned, gfp_mask, order);
+		unsigned long limit = zone_page_state(zone,
+				NR_SLAB_RECLAIMABLE) - nr_pages;
+
+		while (shrink_slab(sc.nr_scanned, gfp_mask, order) &&
+			zone_page_state(zone, NR_SLAB_RECLAIMABLE) > limit)
+			;
 	}
 
 	p->reclaim_state = NULL;
@@ -1609,7 +1622,8 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 	int node_id;
 
 	/*
-	 * Zone reclaim reclaims unmapped file backed pages.
+	 * Zone reclaim reclaims unmapped file backed pages and
+	 * slab pages if we are over the defined limits.
 	 *
 	 * A small portion of unmapped file backed pages is needed for
 	 * file I/O otherwise pages read by file I/O will be immediately
@@ -1618,7 +1632,9 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
 	 * unmapped file backed pages.
 	 */
 	if (zone_page_state(zone, NR_FILE_PAGES) -
-	    zone_page_state(zone, NR_FILE_MAPPED) <= zone->min_unmapped_pages)
+	    zone_page_state(zone, NR_FILE_MAPPED) <= zone->min_unmapped_pages
+	    && zone_page_state(zone, NR_SLAB_RECLAIMABLE)
+			<= zone->min_slab_pages)
 		return 0;
 
 	/*