Commit 99b42445 authored by Ulf Hansson's avatar Ulf Hansson Committed by Rafael J. Wysocki
Browse files

sched: idle: Respect the CPU system wakeup QoS limit for s2idle 



A CPU system wakeup QoS limit may have been requested by user space. To
avoid breaking this constraint when entering a low power state during
s2idle, let's start to take into account the QoS limit.

Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarDhruva Gole <d-gole@ti.com>
Reviewed-by: default avatarKevin Hilman (TI) <khilman@baylibre.com>
Tested-by: default avatarKevin Hilman (TI) <khilman@baylibre.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/20251125112650.329269-5-ulf.hansson@linaro.org


Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent e2e4695f

drivers/cpuidle/cpuidle.c

+7 −5
Original line number Diff line number Diff line
@@ -184,20 +184,22 @@ static noinstr void enter_s2idle_proper(struct cpuidle_driver *drv, 
 * cpuidle_enter_s2idle - Enter an idle state suitable for suspend-to-idle.

 * @drv: cpuidle driver for the given CPU.

 * @dev: cpuidle device for the given CPU.

 * @latency_limit_ns: Idle state exit latency limit

 *

 * If there are states with the ->enter_s2idle callback, find the deepest of

 * them and enter it with frozen tick.

 */

int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev)

int cpuidle_enter_s2idle(struct cpuidle_driver *drv, struct cpuidle_device *dev,

			 u64 latency_limit_ns)

{

	int index;



	/*

	 * Find the deepest state with ->enter_s2idle present, which guarantees

	 * that interrupts won't be enabled when it exits and allows the tick to

	 * be frozen safely.

	 * Find the deepest state with ->enter_s2idle present that meets the

	 * specified latency limit, which guarantees that interrupts won't be

	 * enabled when it exits and allows the tick to be frozen safely.

	 */

	index = find_deepest_state(drv, dev, U64_MAX, 0, true);

	index = find_deepest_state(drv, dev, latency_limit_ns, 0, true);

	if (index > 0) {

		enter_s2idle_proper(drv, dev, index);

		local_irq_enable();

include/linux/cpuidle.h

+4 −2
Original line number Diff line number Diff line
@@ -248,7 +248,8 @@ extern int cpuidle_find_deepest_state(struct cpuidle_driver *drv, 
				      struct cpuidle_device *dev,

				      u64 latency_limit_ns);

extern int cpuidle_enter_s2idle(struct cpuidle_driver *drv,

				struct cpuidle_device *dev);

				struct cpuidle_device *dev,

				u64 latency_limit_ns);

extern void cpuidle_use_deepest_state(u64 latency_limit_ns);

#else

static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv,
@@ -256,7 +257,8 @@ static inline int cpuidle_find_deepest_state(struct cpuidle_driver *drv, 
					     u64 latency_limit_ns)

{return -ENODEV; }

static inline int cpuidle_enter_s2idle(struct cpuidle_driver *drv,

				       struct cpuidle_device *dev)

				       struct cpuidle_device *dev,

				       u64 latency_limit_ns)

{return -ENODEV; }

static inline void cpuidle_use_deepest_state(u64 latency_limit_ns)

{

kernel/sched/idle.c

+7 −5
Original line number Diff line number Diff line
@@ -131,12 +131,13 @@ void __cpuidle default_idle_call(void) 
}



static int call_cpuidle_s2idle(struct cpuidle_driver *drv,

			       struct cpuidle_device *dev)

			       struct cpuidle_device *dev,

			       u64 max_latency_ns)

{

	if (current_clr_polling_and_test())

		return -EBUSY;



	return cpuidle_enter_s2idle(drv, dev);

	return cpuidle_enter_s2idle(drv, dev, max_latency_ns);

}



static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
@@ -205,12 +206,13 @@ static void cpuidle_idle_call(void) 
		u64 max_latency_ns;



		if (idle_should_enter_s2idle()) {

			max_latency_ns = cpu_wakeup_latency_qos_limit() *

					 NSEC_PER_USEC;



			entered_state = call_cpuidle_s2idle(drv, dev);

			entered_state = call_cpuidle_s2idle(drv, dev,

							    max_latency_ns);

			if (entered_state > 0)

				goto exit_idle;



			max_latency_ns = U64_MAX;

		} else {

			max_latency_ns = dev->forced_idle_latency_limit_ns;

		}