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From: Dimitri Sivanich <sivanich@sgi.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@gentwo.org>,
	David Rientjes <rientjes@google.com>,
	Andi Kleen <andi@firstfloor.org>, Mel Gorman <mel@csn.ul.ie>
Subject: [PATCH] cache align vm_stat
Date: Mon, 24 Oct 2011 11:10:35 -0500	[thread overview]
Message-ID: <20111024161035.GA19820@sgi.com> (raw)

Avoid false sharing of the vm_stat array.

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

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
---
 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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             reply	other threads:[~2011-10-24 16:10 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-24 16:10 Dimitri Sivanich [this message]
2011-10-27  2:31 ` [PATCH] cache align vm_stat Christoph Lameter
2011-10-28 22:54   ` Andrew Morton
2011-10-29  5:22     ` Christoph Lameter
2011-10-31 13:37     ` Dimitri Sivanich
  -- strict thread matches above, loose matches on Subject: below --
2011-10-27  8:50 Mel Gorman
2011-10-27 12:51 ` Dimitri Sivanich
2011-10-27 14:29 ` Mel Gorman

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