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authorChristoph Lameter <cl@linux.com>2014-04-08 02:39:43 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-08 03:36:14 +0400
commit293b6a4c875c3b49853bff7de99954f49f59aa75 (patch)
treec05e009383b80e79f477a8d4aa6f779bab04f668
parent88da03a67674bcd6e9ecf18a0a182cf1303056ba (diff)
downloadlinux-293b6a4c875c3b49853bff7de99954f49f59aa75.tar.xz
vmstat: use raw_cpu_ops to avoid false positives on preemption checks
vm counters are allowed to be racy. Use raw_cpu_ops to avoid the local_irq_disable overhead and to avoid preemption checks which will be added to the __this_cpu operations. [akpm@linux-foundation.org: Add comment. Again.] Signed-off-by: Christoph Lameter <cl@linux.com> Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Dave Chinner <dchinner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/vmstat.h8
1 files changed, 6 insertions, 2 deletions
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index ea4476157e00..45c9cd1daf7a 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -27,9 +27,13 @@ struct vm_event_state {
DECLARE_PER_CPU(struct vm_event_state, vm_event_states);
+/*
+ * vm counters are allowed to be racy. Use raw_cpu_ops to avoid the
+ * local_irq_disable overhead.
+ */
static inline void __count_vm_event(enum vm_event_item item)
{
- __this_cpu_inc(vm_event_states.event[item]);
+ raw_cpu_inc(vm_event_states.event[item]);
}
static inline void count_vm_event(enum vm_event_item item)
@@ -39,7 +43,7 @@ static inline void count_vm_event(enum vm_event_item item)
static inline void __count_vm_events(enum vm_event_item item, long delta)
{
- __this_cpu_add(vm_event_states.event[item], delta);
+ raw_cpu_add(vm_event_states.event[item], delta);
}
static inline void count_vm_events(enum vm_event_item item, long delta)