Subject: [merged] vmstat-use-raw_cpu_ops-to-avoid-false-positives-on-preemption-checks.patch removed from -mm tree
To: cl@xxxxxxxxx,dchinner@xxxxxxxxxx,sergey.senozhatsky@xxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 08 Apr 2014 14:48:17 -0700
The patch titled
Subject: vmstat: use raw_cpu_ops to avoid false positives on preemption checks
has been removed from the -mm tree. Its filename was
vmstat-use-raw_cpu_ops-to-avoid-false-positives-on-preemption-checks.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Christoph Lameter <cl@xxxxxxxxx>
Subject: 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@xxxxxxxxxxxxxxxxxxxx: Add comment. Again.]
Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
Reported-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/vmstat.h | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff -puN include/linux/vmstat.h~vmstat-use-raw_cpu_ops-to-avoid-false-positives-on-preemption-checks include/linux/vmstat.h
--- a/include/linux/vmstat.h~vmstat-use-raw_cpu_ops-to-avoid-false-positives-on-preemption-checks
+++ a/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 v
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)
_
Patches currently in -mm which might be from cl@xxxxxxxxx are
origin.patch
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