Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 07/40] mm/vmstat.c: cache align vm_stat | Date | Thu, 26 Jul 2012 14:29:25 -0700 |
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From: Greg KH <gregkh@linuxfoundation.org>
3.0-stable review patch. If anyone has any objections, please let me know.
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From: Dimitri Sivanich <sivanich@sgi.com>
commit a1cb2c60ddc98ff4e5246f410558805401ceee67 upstream.
Stable note: Not tracked on Bugzilla. This patch is known to make a big difference to tmpfs performance on larger machines.
This was found to adversely affect tmpfs I/O performance.
Tests run on a 640 cpu UV system.
With 120 threads doing parallel writes, each to different tmpfs mounts: No patch: ~300 MB/sec With vm_stat alignment: ~430 MB/sec
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Acked-by: Christoph Lameter <cl@gentwo.org> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mel Gorman <mgorman@suse.de>
--- mm/vmstat.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/vmstat.c +++ b/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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