intel_idle: replace conditionals with static_cpu_has(X86_FEATURE_ARAT) (0563bb7b) · Commits · 戴 / test

If the 'arat' cpu flag is set, then the conditionals in intel_idle() that guard calling tick_broadcast_enter()/exit() will never be true. Use static_cpu_has(X86_FEATURE_ARAT) to create a fast path to replace the conditional. Signed-off-by:

Jason Baron <jbaron@akamai.com> Acked-by:

Jacob Pan <jacob.jun.pan@linux.intel.com> Signed-off-by:

Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/idle/intel_idle.c

+11 −5

Original line number	Diff line number	Diff line
		@@ -913,8 +913,7 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev,
		struct cpuidle_state *state = &drv->states[index];
		unsigned long eax = flg2MWAIT(state->flags);
		unsigned int cstate;

		cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) & MWAIT_CSTATE_MASK) + 1;
		bool uninitialized_var(tick);

		/*
		* NB: if CPUIDLE_FLAG_TLB_FLUSHED is set, this idle transition
		@@ -923,12 +922,19 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev,
		* useful with this knowledge.
		*/

		if (!(lapic_timer_reliable_states & (1 << (cstate))))
		if (!static_cpu_has(X86_FEATURE_ARAT)) {
		cstate = (((eax) >> MWAIT_SUBSTATE_SIZE) &
		MWAIT_CSTATE_MASK) + 1;
		tick = false;
		if (!(lapic_timer_reliable_states & (1 << (cstate)))) {
		tick = true;
		tick_broadcast_enter();
		}
		}

		mwait_idle_with_hints(eax, ecx);

		if (!(lapic_timer_reliable_states & (1 << (cstate))))
		if (!static_cpu_has(X86_FEATURE_ARAT) && tick)
		tick_broadcast_exit();

		return index;

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