[PATCH] cache align vm_stat

[Dimitri Sivanich]

Avoid false sharing of the vm_stat array.

This was found to adversely affect tmpfs I/O performance.

Signed-off-by: Dimitri Sivanich <sivanich@xxxxxxx>
---
 mm/vmstat.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux/mm/vmstat.c
===================================================================
--- linux.orig/mm/vmstat.c
+++ linux/mm/vmstat.c
@@ -78,7 +78,7 @@ void vm_events_fold_cpu(int cpu)
  *
  * vm_stat contains the global counters
  */
-atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
+atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
 EXPORT_SYMBOL(vm_stat);
 
 #ifdef CONFIG_SMP
--
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