[PATCH 1/2] cpuidle: Avoid calls to cpuidle_resume|pause() for s2idle
flat view
STALE1814d
From: Ulf Hansson <hidden>
Date: 2021-09-29 14:45:02
Also in:
linux-pm, lkml
Subsystem:
cpu idle time management framework, hibernation (aka software suspend, aka swsusp), scheduler, suspend to ram, the rest · Maintainers:
"Rafael J. Wysocki", Daniel Lezcano, Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
In s2idle_enter(), cpuidle_resume|pause() are invoked to re-allow calls to the cpuidle callbacks during s2idle operations. This is needed because cpuidle is paused in-between in dpm_suspend_noirq() and dpm_resume_noirq(). However, calling cpuidle_resume|pause() from s2idle_enter() looks a bit superfluous, as it also causes all CPUs to be waken up when the first CPU wakes up from s2idle. Therefore, let's drop the calls to cpuidle_resume|pause() from s2idle_enter(). To make this work, let's also adopt the path in the cpuidle_idle_call() to allow cpuidle callbacks to be invoked for s2idle, even if cpuidle has been paused. Signed-off-by: Ulf Hansson <redacted> --- drivers/cpuidle/cpuidle.c | 7 ++++++- include/linux/cpuidle.h | 2 ++ kernel/power/suspend.c | 2 -- kernel/sched/idle.c | 40 ++++++++++++++++++++++----------------- 4 files changed, 31 insertions(+), 20 deletions(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index ef2ea1b12cd8..c76747e497e7 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c@@ -49,7 +49,12 @@ void disable_cpuidle(void) bool cpuidle_not_available(struct cpuidle_driver *drv, struct cpuidle_device *dev) { - return off || !initialized || !drv || !dev || !dev->enabled; + return off || !drv || !dev || !dev->enabled; +} + +bool cpuidle_paused(void) +{ + return !initialized; } /**
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index fce476275e16..51698b385ab5 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h@@ -165,6 +165,7 @@ extern void cpuidle_pause_and_lock(void); extern void cpuidle_resume_and_unlock(void); extern void cpuidle_pause(void); extern void cpuidle_resume(void); +extern bool cpuidle_paused(void); extern int cpuidle_enable_device(struct cpuidle_device *dev); extern void cpuidle_disable_device(struct cpuidle_device *dev); extern int cpuidle_play_dead(void);
@@ -204,6 +205,7 @@ static inline void cpuidle_pause_and_lock(void) { } static inline void cpuidle_resume_and_unlock(void) { } static inline void cpuidle_pause(void) { } static inline void cpuidle_resume(void) { } +static inline bool cpuidle_paused(void) {return true; } static inline int cpuidle_enable_device(struct cpuidle_device *dev) {return -ENODEV; } static inline void cpuidle_disable_device(struct cpuidle_device *dev) { }
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index eb75f394a059..388a5de4836e 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c@@ -97,7 +97,6 @@ static void s2idle_enter(void) raw_spin_unlock_irq(&s2idle_lock); cpus_read_lock(); - cpuidle_resume(); /* Push all the CPUs into the idle loop. */ wake_up_all_idle_cpus();
@@ -105,7 +104,6 @@ static void s2idle_enter(void) swait_event_exclusive(s2idle_wait_head, s2idle_state == S2IDLE_STATE_WAKE); - cpuidle_pause(); cpus_read_unlock(); raw_spin_lock_irq(&s2idle_lock);
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index d17b0a5ce6ac..3bc3a2c46731 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c@@ -158,6 +158,17 @@ static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev, return cpuidle_enter(drv, dev, next_state); } +static void cpuidle_deepest_state(struct cpuidle_driver *drv, + struct cpuidle_device *dev, + u64 max_latency_ns) +{ + int next_state; + + tick_nohz_idle_stop_tick(); + next_state = cpuidle_find_deepest_state(drv, dev, max_latency_ns); + call_cpuidle(drv, dev, next_state); +} + /** * cpuidle_idle_call - the main idle function *
@@ -189,6 +200,7 @@ static void cpuidle_idle_call(void) */ if (cpuidle_not_available(drv, dev)) { +default_idle: tick_nohz_idle_stop_tick(); default_idle_call();
@@ -204,25 +216,19 @@ static void cpuidle_idle_call(void) * timekeeping to prevent timer interrupts from kicking us out of idle * until a proper wakeup interrupt happens. */ + if (idle_should_enter_s2idle()) { + entered_state = call_cpuidle_s2idle(drv, dev); + if (entered_state <= 0) + cpuidle_deepest_state(drv, dev, U64_MAX); + goto exit_idle; + } - if (idle_should_enter_s2idle() || dev->forced_idle_latency_limit_ns) { - u64 max_latency_ns; - - if (idle_should_enter_s2idle()) { - - entered_state = call_cpuidle_s2idle(drv, dev); - if (entered_state > 0) - goto exit_idle; - - max_latency_ns = U64_MAX; - } else { - max_latency_ns = dev->forced_idle_latency_limit_ns; - } - - tick_nohz_idle_stop_tick(); + if (cpuidle_paused()) + goto default_idle; - next_state = cpuidle_find_deepest_state(drv, dev, max_latency_ns); - call_cpuidle(drv, dev, next_state); + if (dev->forced_idle_latency_limit_ns) { + cpuidle_deepest_state(drv, dev, + dev->forced_idle_latency_limit_ns); } else { bool stop_tick = true;
--
2.25.1
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