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cpuidle: Select a different state on tick_broadcast_enter() failures 

If tick_broadcast_enter() fails in cpuidle_enter_state(),
try to find another idle state to enter instead of invoking
default_idle_call() immediately and returning -EBUSY which
should increase the chances of saving some energy in those
cases.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Kevin Hilman <khilman@linaro.org>
hifive-unleashed-5.1
Rafael J. Wysocki 2015-05-10 01:19:52 +02:00
parent 827a5aefc5
commit 0d94039fab
1 changed files with 15 additions and 5 deletions
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20
drivers/cpuidle/cpuidle.c
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@ -73,7 +73,10 @@ int cpuidle_play_dead(void)
}
static int find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev, bool freeze)
struct cpuidle_device *dev,
unsigned int max_latency,
unsigned int forbidden_flags,
bool freeze)
{
unsigned int latency_req = 0;
int i, ret = freeze ? -1 : CPUIDLE_DRIVER_STATE_START - 1;
@ -83,6 +86,8 @@ static int find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_state_usage *su = &dev->states_usage[i];
if (s->disabled || su->disable || s->exit_latency <= latency_req
|| s->exit_latency > max_latency
|| (s->flags & forbidden_flags)
|| (freeze && !s->enter_freeze))
continue;
@ -100,7 +105,7 @@ static int find_deepest_state(struct cpuidle_driver *drv,
int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
{
return find_deepest_state(drv, dev, false);
return find_deepest_state(drv, dev, UINT_MAX, 0, false);
}
static void enter_freeze_proper(struct cpuidle_driver *drv,
@ -139,7 +144,7 @@ int cpuidle_enter_freeze(struct cpuidle_driver *drv, struct cpuidle_device *dev)
* that interrupts won't be enabled when it exits and allows the tick to
* be frozen safely.
*/
index = find_deepest_state(drv, dev, true);
index = find_deepest_state(drv, dev, UINT_MAX, 0, true);
if (index >= 0)
enter_freeze_proper(drv, dev, index);
@ -168,8 +173,13 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
* CPU as a broadcast timer, this call may fail if it is not available.
*/
if (broadcast && tick_broadcast_enter()) {
default_idle_call();
return -EBUSY;
index = find_deepest_state(drv, dev, target_state->exit_latency,
CPUIDLE_FLAG_TIMER_STOP, false);
if (index < 0) {
default_idle_call();
return -EBUSY;
}
target_state = &drv->states[index];
}
/* Take note of the planned idle state. */