Some of the checks which may force tick_do_broadcast_on_off() to return early can be done before taking locks. This would make these codepaths faster.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- kernel/time/tick-broadcast.c | 20 +++++++------------- 1 file changed, 7 insertions(+), 13 deletions(-)
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 1597d03..3b07569 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -329,27 +329,22 @@ unlock: */ static void tick_do_broadcast_on_off(unsigned long *reason) { - struct clock_event_device *bc, *dev; - struct tick_device *td; + struct tick_device *td = tick_get_cpu_device(); + struct clock_event_device *bc, *dev = td->evtdev; + int cpu = smp_processor_id(), bc_stopped; unsigned long flags; - int cpu, bc_stopped; - - raw_spin_lock_irqsave(&tick_broadcast_lock, flags); - - cpu = smp_processor_id(); - td = tick_get_device(cpu); - dev = td->evtdev; - bc = tick_broadcast_device.evtdev;
/* * Is the device not affected by the powerstate ? */ if (!dev || !(dev->features & CLOCK_EVT_FEAT_C3STOP)) - goto out; + return;
if (!tick_device_is_functional(dev)) - goto out; + return;
+ raw_spin_lock_irqsave(&tick_broadcast_lock, flags); + bc = tick_broadcast_device.evtdev; bc_stopped = cpumask_empty(tick_broadcast_mask);
switch (*reason) { @@ -385,7 +380,6 @@ static void tick_do_broadcast_on_off(unsigned long *reason) else tick_broadcast_setup_oneshot(bc); } -out: raw_spin_unlock_irqrestore(&tick_broadcast_lock, flags); }