Commit d7d34d5e authored Apr 28, 2017 by Paul E. McKenney

sched: Rely on synchronize_rcu_mult() de-duplication



The synchronize_rcu_mult() function now detects duplicate requests
for the same grace-period flavor and waits only once for each flavor.
This commit therefore removes the ugly #ifdef from sched_cpu_deactivate()
because synchronize_rcu_mult(call_rcu, call_rcu_sched) now does what
the #ifdef used to be needed for.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

parent 68ab0b42

kernel/sched/core.c

+1 −7

Original line number	Diff line number	Diff line
		@@ -5874,15 +5874,9 @@ int sched_cpu_deactivate(unsigned int cpu)
		* users of this state to go away such that all new such users will
		* observe it.
		*
		* For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might
		* not imply sync_sched(), so wait for both.
		*
		* Do sync before park smpboot threads to take care the rcu boost case.
		*/
		if (IS_ENABLED(CONFIG_PREEMPT))
		synchronize_rcu_mult(call_rcu, call_rcu_sched);
		else
		synchronize_rcu();

		if (!sched_smp_initialized)
		return 0;