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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: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Reviewed-by: Kevin Hilman (TI) <khilman@baylibre.com>
Tested-by: Kevin Hilman (TI) <khilman@baylibre.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/20251125112650.329269-5-ulf.hansson@linaro.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
pull/1354/merge
Ulf Hansson 2025-11-25 12:26:45 +01:00 committed by Rafael J. Wysocki
parent e2e4695f01
commit 99b42445f4
3 changed files with 18 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/cpuidle/cpuidle.c
View File

@ -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();

6
include/linux/cpuidle.h
View File

@ -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)
{

12
kernel/sched/idle.c
View File

@ -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;
}