linux-kernel - [PATCH RFC 1/2] sched/core: Convert synchronize_rcu_mult to synchronize

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Message-Id: <20181002012012.13133-1-joel@joelfernandes.org>
Date:   Mon,  1 Oct 2018 18:20:11 -0700
From:   Joel Fernandes <joel@...lfernandes.org>
To:     linux-kernel@...r.kernel.org
Cc:     kernel-team@...roid.com,
        "Joel Fernandes (Google)" <joel@...lfernandes.org>,
        Ingo Molnar <mingo@...hat.com>,
        Josh Triplett <josh@...htriplett.org>,
        Lai Jiangshan <jiangshanlai@...il.com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        "Paul E. McKenney" <paulmck@...ux.ibm.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Steven Rostedt <rostedt@...dmis.org>
Subject: [PATCH RFC 1/2] sched/core: Convert synchronize_rcu_mult to synchronize_rcu

From: "Joel Fernandes (Google)" <joel@...lfernandes.org>

synchronize_rcu_mult is now obsolete since all the different RCU flavors
have been consolidated and the API is now common on the updater side.
sched/core.c is the only user of it. All call_rcu_<flavor> calls boil
down to the same call_rcu. So there's no point in calling
synchronize_rcu_mult infact it could potentially be slower due to
waiting for the call_rcu callback twice. Just call synchronize_rcu here
which should do the job.

Signed-off-by: Joel Fernandes (Google) <joel@...lfernandes.org>
---
 kernel/sched/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 625bc9897f62..d8311f3cf58c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5791,7 +5791,7 @@ int sched_cpu_deactivate(unsigned int cpu)
 	 *
 	 * Do sync before park smpboot threads to take care the rcu boost case.
 	 */
-	synchronize_rcu_mult(call_rcu, call_rcu_sched);
+	synchronize_rcu();
 
 	if (!sched_smp_initialized)
 		return 0;
-- 
2.19.0.605.g01d371f741-goog