sched: Replace synchronize_sched() with synchronize_rcu() (b290ebcf) · Commits · 戴 / test

Now that synchronize_rcu() waits for preempt-disable regions of code as well as RCU read-side critical sections, synchronize_sched() can be replaced by synchronize_rcu(), in fact, synchronize_sched() is now completely equivalent to synchronize_rcu(). This commit therefore replaces synchronize_sched() with synchronize_rcu() so that synchronize_sched() can eventually be removed entirely. Signed-off-by:

Paul E. McKenney <paulmck@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>

kernel/sched/cpufreq.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -48,8 +48,8 @@ EXPORT_SYMBOL_GPL(cpufreq_add_update_util_hook);
		*
		* Clear the update_util_data pointer for the given CPU.
		*
		* Callers must use RCU-sched callbacks to free any memory that might be
		* accessed via the old update_util_data pointer or invoke synchronize_sched()
		* Callers must use RCU callbacks to free any memory that might be
		* accessed via the old update_util_data pointer or invoke synchronize_rcu()
		* right after this function to avoid use-after-free.
		*/
		void cpufreq_remove_update_util_hook(int cpu)

kernel/sched/cpufreq_schedutil.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -859,7 +859,7 @@ static void sugov_stop(struct cpufreq_policy *policy)
		for_each_cpu(cpu, policy->cpus)
		cpufreq_remove_update_util_hook(cpu);

		synchronize_sched();
		synchronize_rcu();

		if (!policy->fast_switch_enabled) {
		irq_work_sync(&sg_policy->irq_work);

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