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authorChristoph Lameter <cl@linux.com>2013-09-11 14:21:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:57:31 -0700
commit2bb921e526656556e68f99f5f15a4a1bf2691844 (patch)
tree91b009a59938d7713de0781df9d5c0c2eacfc51f /mm/page_alloc.c
parentd2cf5ad6312ca9913464fac40fb47ba47ad945c4 (diff)
downloadop-kernel-dev-2bb921e526656556e68f99f5f15a4a1bf2691844.zip
op-kernel-dev-2bb921e526656556e68f99f5f15a4a1bf2691844.tar.gz
vmstat: create separate function to fold per cpu diffs into local counters
The main idea behind this patchset is to reduce the vmstat update overhead by avoiding interrupt enable/disable and the use of per cpu atomics. This patch (of 3): It is better to have a separate folding function because refresh_cpu_vm_stats() also does other things like expire pages in the page allocator caches. If we have a separate function then refresh_cpu_vm_stats() is only called from the local cpu which allows additional optimizations. The folding function is only called when a cpu is being downed and therefore no other processor will be accessing the counters. Also simplifies synchronization. [akpm@linux-foundation.org: fix UP build] Signed-off-by: Christoph Lameter <cl@linux.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> CC: Tejun Heo <tj@kernel.org> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r--mm/page_alloc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 42c5930..f885eb8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5435,7 +5435,7 @@ static int page_alloc_cpu_notify(struct notifier_block *self,
* This is only okay since the processor is dead and cannot
* race with what we are doing.
*/
- refresh_cpu_vm_stats(cpu);
+ cpu_vm_stats_fold(cpu);
}
return NOTIFY_OK;
}
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