[PATCH] Use zoned VM Counters for NUMA statistics V2

[Christoph Lameter <clameter@sgi.com>]

The numa statistics are really event counters. But they are per
node and so we have had special treatment for these counters
through additional fields on the pcp structure. We can now use the
per zone nature of the zoned VM counters to realize these.

This will shrink the size of the pcp structure on NUMA systems
so that it fits again into one cacheline on 32 bit NUMA
with a 64 byte cacheline. Plus we will have some room to add
additional per zone counters that may become necessary.


Bits	Prior pcp size	  	Size after patch
------------------------------------------------
64	128 bytes (16 words)	80 bytes (10 words)
32	152 bytes (19 words)	48 bytes (14 words)


Remove the special statistics for numa and replace them with
zoned vm counters.

This has the side effect that global sums of these events now show up
in /proc/vmstat.

V1->V2:
- Remove useless cpu parameter to zone_statistics.
- Move zone_statistics to vmstat.c

Applies on top of ZVC v4 patchset and the eventcounter patchset.
Patch could be made to apply on top of ZVC 4 alone if needed.

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.17-rc6-cl/mm/mempolicy.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/mempolicy.c	2006-06-12 12:42:52.033043000 -0700
+++ linux-2.6.17-rc6-cl/mm/mempolicy.c	2006-06-16 11:01:45.129015454 -0700
@@ -1204,10 +1204,8 @@ static struct page *alloc_page_interleav
 
 	zl = NODE_DATA(nid)->node_zonelists + gfp_zone(gfp);
 	page = __alloc_pages(gfp, order, zl);
-	if (page && page_zone(page) == zl->zones[0]) {
-		zone_pcp(zl->zones[0],get_cpu())->interleave_hit++;
-		put_cpu();
-	}
+	if (page && page_zone(page) == zl->zones[0])
+		inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
 	return page;
 }
 
Index: linux-2.6.17-rc6-cl/mm/vmstat.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/vmstat.c	2006-06-16 11:01:43.872257402 -0700
+++ linux-2.6.17-rc6-cl/mm/vmstat.c	2006-06-16 11:01:45.129991956 -0700
@@ -188,9 +188,8 @@ EXPORT_SYMBOL(mod_zone_page_state);
  * in between and therefore the atomicity vs. interrupt cannot be exploited
  * in a useful way here.
  */
-void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
+static void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 {
-	struct zone *zone = page_zone(page);
 	s8 *p = diff_pointer(zone, item);
 
 	(*p)++;
@@ -200,6 +199,11 @@ void __inc_zone_page_state(struct page *
 		*p = 0;
 	}
 }
+
+void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
+{
+	__inc_zone_state(page_zone(page), item);
+}
 EXPORT_SYMBOL(__inc_zone_page_state);
 
 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
@@ -216,22 +220,23 @@ void __dec_zone_page_state(struct page *
 }
 EXPORT_SYMBOL(__dec_zone_page_state);
 
+void inc_zone_state(struct zone *zone, enum zone_stat_item item)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__inc_zone_state(zone, item);
+	local_irq_restore(flags);
+}
+
 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 {
 	unsigned long flags;
 	struct zone *zone;
-	s8 *p;
 
 	zone = page_zone(page);
 	local_irq_save(flags);
-	p = diff_pointer(zone, item);
-
-	(*p)++;
-
-	if (unlikely(*p > STAT_THRESHOLD)) {
-		zone_page_state_add(*p, zone, item);
-		*p = 0;
-	}
+	__inc_zone_state(zone, item);
 	local_irq_restore(flags);
 }
 EXPORT_SYMBOL(inc_zone_page_state);
@@ -356,6 +361,28 @@ void dec_zone_page_state(struct page *pa
 EXPORT_SYMBOL(dec_zone_page_state);
 #endif
 
+#ifdef CONFIG_NUMA
+/*
+ * zonelist = the list of zones passed to the allocator
+ * z 	    = the zone from which the allocation occurred.
+ *
+ * Must be called with interrupts disabled.
+ */
+void zone_statistics(struct zonelist *zonelist, struct zone *z)
+{
+	if (z->zone_pgdat == zonelist->zones[0]->zone_pgdat) {
+		__inc_zone_state(z, NUMA_HIT);
+	} else {
+		__inc_zone_state(z, NUMA_MISS);
+		__inc_zone_state(zonelist->zones[0], NUMA_FOREIGN);
+	}
+	if (z->zone_pgdat == NODE_DATA(numa_node_id()))
+		__inc_zone_state(z, NUMA_LOCAL);
+	else
+		__inc_zone_state(z, NUMA_OTHER);
+}
+#endif
+
 #ifdef CONFIG_PROC_FS
 
 #include <linux/seq_file.h>
@@ -428,6 +455,14 @@ static char *vmstat_text[] = {
 	"nr_unstable",
 	"nr_bounce",
 
+#ifdef CONFIG_NUMA
+	"numa_hit",
+	"numa_miss",
+	"numa_foreign",
+	"numa_interleave",
+	"numa_local",
+	"numa_other",
+#endif
 #ifdef CONFIG_VM_EVENT_COUNTERS
 	"pgpgin",
 	"pgpgout",
@@ -550,21 +585,6 @@ static int zoneinfo_show(struct seq_file
 					   pageset->pcp[j].high,
 					   pageset->pcp[j].batch);
 			}
-#ifdef CONFIG_NUMA
-			seq_printf(m,
-				   "\n            numa_hit:       %lu"
-				   "\n            numa_miss:      %lu"
-				   "\n            numa_foreign:   %lu"
-				   "\n            interleave_hit: %lu"
-				   "\n            local_node:     %lu"
-				   "\n            other_node:     %lu",
-				   pageset->numa_hit,
-				   pageset->numa_miss,
-				   pageset->numa_foreign,
-				   pageset->interleave_hit,
-				   pageset->local_node,
-				   pageset->other_node);
-#endif
 		}
 		seq_printf(m,
 			   "\n  all_unreclaimable: %u"
Index: linux-2.6.17-rc6-cl/mm/page_alloc.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/mm/page_alloc.c	2006-06-16 11:01:43.841009339 -0700
+++ linux-2.6.17-rc6-cl/mm/page_alloc.c	2006-06-16 11:01:45.147568992 -0700
@@ -724,27 +724,6 @@ void drain_local_pages(void)
 }
 #endif /* CONFIG_PM */
 
-static void zone_statistics(struct zonelist *zonelist, struct zone *z, int cpu)
-{
-#ifdef CONFIG_NUMA
-	pg_data_t *pg = z->zone_pgdat;
-	pg_data_t *orig = zonelist->zones[0]->zone_pgdat;
-	struct per_cpu_pageset *p;
-
-	p = zone_pcp(z, cpu);
-	if (pg == orig) {
-		p->numa_hit++;
-	} else {
-		p->numa_miss++;
-		zone_pcp(zonelist->zones[0], cpu)->numa_foreign++;
-	}
-	if (pg == NODE_DATA(numa_node_id()))
-		p->local_node++;
-	else
-		p->other_node++;
-#endif
-}
-
 /*
  * Free a 0-order page
  */
@@ -842,7 +821,7 @@ again:
 	}
 
 	__count_zone_vm_events(PGALLOC, zone, 1 << order);
-	zone_statistics(zonelist, zone, cpu);
+	zone_statistics(zonelist, zone);
 	local_irq_restore(flags);
 	put_cpu();
 
Index: linux-2.6.17-rc6-cl/include/linux/mmzone.h
===================================================================
--- linux-2.6.17-rc6-cl.orig/include/linux/mmzone.h	2006-06-16 01:03:42.306128489 -0700
+++ linux-2.6.17-rc6-cl/include/linux/mmzone.h	2006-06-16 11:01:45.148545494 -0700
@@ -57,6 +57,14 @@ enum zone_stat_item {
 	NR_WRITEBACK,
 	NR_UNSTABLE,	/* NFS unstable pages */
 	NR_BOUNCE,
+#ifdef CONFIG_NUMA
+	NUMA_HIT,
+	NUMA_MISS,
+	NUMA_FOREIGN,
+	NUMA_INTERLEAVE_HIT,
+	NUMA_LOCAL,
+	NUMA_OTHER,
+#endif
 	NR_VM_ZONE_STAT_ITEMS };
 
 struct per_cpu_pages {
@@ -71,15 +79,6 @@ struct per_cpu_pageset {
 #ifdef CONFIG_SMP
 	s8 vm_stat_diff[NR_VM_ZONE_STAT_ITEMS];
 #endif
-
-#ifdef CONFIG_NUMA
-	unsigned long numa_hit;		/* allocated in intended node */
-	unsigned long numa_miss;	/* allocated in non intended node */
-	unsigned long numa_foreign;	/* was intended here, hit elsewhere */
-	unsigned long interleave_hit; 	/* interleaver prefered this zone */
-	unsigned long local_node;	/* allocation from local node */
-	unsigned long other_node;	/* allocation from other node */
-#endif
 } ____cacheline_aligned_in_smp;
 
 #ifdef CONFIG_NUMA
Index: linux-2.6.17-rc6-cl/drivers/base/node.c
===================================================================
--- linux-2.6.17-rc6-cl.orig/drivers/base/node.c	2006-06-16 01:03:42.305151987 -0700
+++ linux-2.6.17-rc6-cl/drivers/base/node.c	2006-06-16 11:01:45.149521996 -0700
@@ -94,28 +94,6 @@ static SYSDEV_ATTR(meminfo, S_IRUGO, nod
 
 static ssize_t node_read_numastat(struct sys_device * dev, char * buf)
 {
-	unsigned long numa_hit, numa_miss, interleave_hit, numa_foreign;
-	unsigned long local_node, other_node;
-	int i, cpu;
-	pg_data_t *pg = NODE_DATA(dev->id);
-	numa_hit = 0;
-	numa_miss = 0;
-	interleave_hit = 0;
-	numa_foreign = 0;
-	local_node = 0;
-	other_node = 0;
-	for (i = 0; i < MAX_NR_ZONES; i++) {
-		struct zone *z = &pg->node_zones[i];
-		for_each_online_cpu(cpu) {
-			struct per_cpu_pageset *ps = zone_pcp(z,cpu);
-			numa_hit += ps->numa_hit;
-			numa_miss += ps->numa_miss;
-			numa_foreign += ps->numa_foreign;
-			interleave_hit += ps->interleave_hit;
-			local_node += ps->local_node;
-			other_node += ps->other_node;
-		}
-	}
 	return sprintf(buf,
 		       "numa_hit %lu\n"
 		       "numa_miss %lu\n"
@@ -123,12 +101,12 @@ static ssize_t node_read_numastat(struct
 		       "interleave_hit %lu\n"
 		       "local_node %lu\n"
 		       "other_node %lu\n",
-		       numa_hit,
-		       numa_miss,
-		       numa_foreign,
-		       interleave_hit,
-		       local_node,
-		       other_node);
+		       node_page_state(dev->id, NUMA_HIT),
+		       node_page_state(dev->id, NUMA_MISS),
+		       node_page_state(dev->id, NUMA_FOREIGN),
+		       node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
+		       node_page_state(dev->id, NUMA_LOCAL),
+		       node_page_state(dev->id, NUMA_OTHER));
 }
 static SYSDEV_ATTR(numastat, S_IRUGO, node_read_numastat, NULL);
 
Index: linux-2.6.17-rc6-cl/include/linux/vmstat.h
===================================================================
--- linux-2.6.17-rc6-cl.orig/include/linux/vmstat.h	2006-06-16 11:01:43.838079833 -0700
+++ linux-2.6.17-rc6-cl/include/linux/vmstat.h	2006-06-16 11:01:45.149521996 -0700
@@ -56,9 +56,15 @@ static inline unsigned long node_page_st
 #endif
 		zone_page_state(&zones[ZONE_DMA], item);
 }
+
+extern void zone_statistics(struct zonelist *, struct zone *);
+
 #else
+
 #define node_page_state(node, item) global_page_state(item)
-#endif
+#define zone_statistics(_zl,_z) do { } while (0)
+
+#endif /* CONFIG_NUMA */
 
 void __mod_zone_page_state(struct zone *, enum zone_stat_item item, int);
 void __inc_zone_page_state(struct page *, enum zone_stat_item);
@@ -78,6 +84,8 @@ static inline void zap_zone_vm_stats(str
 	memset(zone->vm_stat, 0, sizeof(zone->vm_stat));
 }
 
+extern void inc_zone_state(struct zone *, enum zone_stat_item);
+
 #ifdef CONFIG_SMP
 void refresh_cpu_vm_stats(int);
 void refresh_vm_stats(void);
@@ -152,4 +160,4 @@ extern void vm_events_fold_cpu(int cpu);
 #define __count_zone_vm_events(item, zone, delta) \
 			__count_vm_events(item##_DMA + zone_idx(zone), delta)
 
-#endif
+#endif /* _LINUX_VMSTAT_H */
-
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