[PATCH] Reorder ZVCs according to cacheline

The global and per zone counter sums are in arrays of longs.  Reorder the ZVCs
so that the most frequently used ZVCs are put into the same cacheline.  That
way calculations of the global, node and per zone vm state touches only a
single cacheline.  This is mostly important for 64 bit systems were one 128
byte cacheline takes only 8 longs.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mmzone.h

@@ -47,6 +47,7 @@ struct zone_padding {
 #endif
 
 enum zone_stat_item {
+	/* First 128 byte cacheline (assuming 64 bit words) */
 	NR_FREE_PAGES,
 	NR_INACTIVE,
 	NR_ACTIVE,
@@ -54,11 +55,12 @@ enum zone_stat_item {
 	NR_FILE_MAPPED,	/* pagecache pages mapped into pagetables.
 			   only modified from process context */
 	NR_FILE_PAGES,
-	NR_SLAB_RECLAIMABLE,
-	NR_SLAB_UNRECLAIMABLE,
-	NR_PAGETABLE,	/* used for pagetables */
 	NR_FILE_DIRTY,
 	NR_WRITEBACK,
+	/* Second 128 byte cacheline */
+	NR_SLAB_RECLAIMABLE,
+	NR_SLAB_UNRECLAIMABLE,
+	NR_PAGETABLE,		/* used for pagetables */
 	NR_UNSTABLE_NFS,	/* NFS unstable pages */
 	NR_BOUNCE,
 	NR_VMSCAN_WRITE,

mm/vmstat.c

@@ -447,11 +447,11 @@ static const char * const vmstat_text[] = {
 	"nr_anon_pages",
 	"nr_mapped",
 	"nr_file_pages",
+	"nr_dirty",
+	"nr_writeback",
 	"nr_slab_reclaimable",
 	"nr_slab_unreclaimable",
 	"nr_page_table_pages",
-	"nr_dirty",
-	"nr_writeback",
 	"nr_unstable",
 	"nr_bounce",
 	"nr_vmscan_write",