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authorChristoph Lameter <cl@linux.com>2010-12-08 16:22:55 +0100
committerTejun Heo <tj@kernel.org>2010-12-17 15:07:19 +0100
commit909ea96468096b07fbb41aaf69be060d92bd9271 (patch)
treea7e015edd96b5f674874fe78cdd889769e130a2a /kernel/time
parent780f36d8b3fa9572f731d4fb85067b2e45e6f993 (diff)
downloadop-kernel-dev-909ea96468096b07fbb41aaf69be060d92bd9271.zip
op-kernel-dev-909ea96468096b07fbb41aaf69be060d92bd9271.tar.gz
core: Replace __get_cpu_var with __this_cpu_read if not used for an address.
__get_cpu_var() can be replaced with this_cpu_read and will then use a single read instruction with implied address calculation to access the correct per cpu instance. However, the address of a per cpu variable passed to __this_cpu_read() cannot be determined (since it's an implied address conversion through segment prefixes). Therefore apply this only to uses of __get_cpu_var where the address of the variable is not used. Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Hugh Dickins <hughd@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/tick-common.c2
-rw-r--r--kernel/time/tick-oneshot.c4
2 files changed, 3 insertions, 3 deletions
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index b6b898d..051bc80 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -49,7 +49,7 @@ struct tick_device *tick_get_device(int cpu)
*/
int tick_is_oneshot_available(void)
{
- struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
+ struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
return dev && (dev->features & CLOCK_EVT_FEAT_ONESHOT);
}
diff --git a/kernel/time/tick-oneshot.c b/kernel/time/tick-oneshot.c
index aada0e5..5cbc101 100644
--- a/kernel/time/tick-oneshot.c
+++ b/kernel/time/tick-oneshot.c
@@ -95,7 +95,7 @@ int tick_dev_program_event(struct clock_event_device *dev, ktime_t expires,
*/
int tick_program_event(ktime_t expires, int force)
{
- struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
+ struct clock_event_device *dev = __this_cpu_read(tick_cpu_device.evtdev);
return tick_dev_program_event(dev, expires, force);
}
@@ -167,7 +167,7 @@ int tick_oneshot_mode_active(void)
int ret;
local_irq_save(flags);
- ret = __get_cpu_var(tick_cpu_device).mode == TICKDEV_MODE_ONESHOT;
+ ret = __this_cpu_read(tick_cpu_device.mode) == TICKDEV_MODE_ONESHOT;
local_irq_restore(flags);
return ret;
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