[PATCH V1 3/3] cpuidle: Use the latency to call find_deepest_idle_state

Daniel Lezcano
2019-11-14T20:49:43Z

As the dev->forced_idle_latency_limit_ns is filled with the latency
value when this function is called, use it as a parameter to the
find_deepest_idle_state() function.

Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
drivers/cpuidle/cpuidle.c | 7 +++++--
include/linux/cpuidle.h | 6 ++++--
kernel/sched/idle.c | 8 +++++++-
3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 62226fadc02d..a02b701fc289 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -122,9 +122,12 @@ void cpuidle_use_deepest_state(u64 latency_limit_ns)
* @dev: cpuidle device for the given CPU.
*/
int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
- struct cpuidle_device *dev)
+ struct cpuidle_device *dev,
+ u64 latency_limit_ns)
{
- return find_deepest_state(drv, dev, UINT_MAX, 0, false);
+ return find_deepest_state(drv, dev,
+ div_u64(latency_limit_ns, NSEC_PER_USEC),
+ 0, false);
}

#ifdef CONFIG_SUSPEND
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 1f3f4dd01e48..b60f35b7d53e 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -207,13 +207,15 @@ static inline struct cpuidle_device *cpuidle_get_device(void) {return NULL; }

#ifdef CONFIG_CPU_IDLE
extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
- struct cpuidle_device *dev);
+ struct cpuidle_device *dev,
+ u64 latency_limit_ns);
extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
struct cpuidle_device *dev);
extern void cpuidle_use_deepest_state(u64 latency_limit_ns);
#else
static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
- struct cpuidle_device *dev)
+ struct cpuidle_device *dev,
+ u64 latency_limit_ns)
{return -ENODEV; }
static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,
struct cpuidle_device *dev)
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 0a817e907192..fd4a8747e602 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -166,6 +166,9 @@ static void cpuidle_idle_call(void)
*/

if (idle_should_enter_s2idle() || dev->forced_idle_latency_limit_ns) {
+
+ u64 latency_limit_ns = dev->forced_idle_latency_limit_ns;
+
if (idle_should_enter_s2idle()) {
rcu_idle_enter();

@@ -176,12 +179,15 @@ static void cpuidle_idle_call(void)
}

rcu_idle_exit();
+
+ latency_limit_ns = U64_MAX;
}

tick_nohz_idle_stop_tick();
rcu_idle_enter();

- next_state = cpuidle_find_deepest_state(drv, dev);
+ next_state = cpuidle_find_deepest_state(drv, dev,
+ latency_limit_ns);
call_cpuidle(drv, dev, next_state);
} else {
bool stop_tick = true;
--
2.17.1