sched / idle: Drop default_idle_call() fallback from call_cpuidle() (51164251) · Commits · 戴 / test

After commit (cpuidle: menu: Fix menu_select() for CPUIDLE_DRIVER_STATE_START == 0) it is clear that menu_select() cannot return negative values. Moreover, ladder_select_state() will never return a negative value too, so make find_deepest_state() return non-negative values too and drop the default_idle_call() fallback from call_cpuidle(). This eliminates one branch from the idle loop and makes the governors and find_deepest_state() handle the case when all states have been disabled from sysfs consistently. Signed-off-by:

Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:

Ingo Molnar <mingo@kernel.org> Tested-by:

Sudeep Holla <sudeep.holla@arm.com>

drivers/cpuidle/cpuidle.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -79,9 +79,9 @@ static int find_deepest_state(struct cpuidle_driver *drv,
		bool freeze)
		{
		unsigned int latency_req = 0;
		int i, ret = -ENXIO;
		int i, ret = 0;

		for (i = 0; i < drv->state_count; i++) {
		for (i = 1; i < drv->state_count; i++) {
		struct cpuidle_state *s = &drv->states[i];
		struct cpuidle_state_usage *su = &dev->states_usage[i];

		@@ -243,7 +243,7 @@ int cpuidle_enter_state(struct cpuidle_device dev, struct cpuidle_driver drv,
		* @drv: the cpuidle driver
		* @dev: the cpuidle device
		*
		* Returns the index of the idle state.
		* Returns the index of the idle state. The return value must not be negative.
		*/
		int cpuidle_select(struct cpuidle_driver drv, struct cpuidle_device dev)
		{

kernel/sched/idle.c

+0 −6

Original line number	Diff line number	Diff line
		@@ -97,12 +97,6 @@ void default_idle_call(void)
		static int call_cpuidle(struct cpuidle_driver drv, struct cpuidle_device dev,
		int next_state)
		{
		/* Fall back to the default arch idle method on errors. */
		if (next_state < 0) {
		default_idle_call();
		return next_state;
		}

		/*
		* The idle task must be scheduled, it is pointless to go to idle, just
		* update no idle residency and return.

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