diff options
| author | Christoph Lameter <cl@linux.com> | 2013-09-11 14:21:30 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-09-11 15:57:31 -0700 |
| commit | 2bb921e526656556e68f99f5f15a4a1bf2691844 (patch) | |
| tree | 91b009a59938d7713de0781df9d5c0c2eacfc51f /include/linux/vmstat.h | |
| parent | d2cf5ad6312ca9913464fac40fb47ba47ad945c4 (diff) | |
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 'include/linux/vmstat.h')
| -rw-r--r-- | include/linux/vmstat.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index c586679b6fef..502767f4e4d4 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -198,7 +198,7 @@ extern void __inc_zone_state(struct zone *, enum zone_stat_item); extern void dec_zone_state(struct zone *, enum zone_stat_item); extern void __dec_zone_state(struct zone *, enum zone_stat_item); -void refresh_cpu_vm_stats(int); +void cpu_vm_stats_fold(int cpu); void refresh_zone_stat_thresholds(void); void drain_zonestat(struct zone *zone, struct per_cpu_pageset *); @@ -255,6 +255,7 @@ static inline void __dec_zone_page_state(struct page *page, static inline void refresh_cpu_vm_stats(int cpu) { } static inline void refresh_zone_stat_thresholds(void) { } +static inline void cpu_vm_stats_fold(int cpu) { } static inline void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset) { } |