From bcbfdd01dce5556a952fae84ef16fd0f12525e7b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 11 Apr 2017 15:50:41 -0700 Subject: rcu: Make non-preemptive schedule be Tasks RCU quiescent state Currently, a call to schedule() acts as a Tasks RCU quiescent state only if a context switch actually takes place. However, just the call to schedule() guarantees that the calling task has moved off of whatever tracing trampoline that it might have been one previously. This commit therefore plumbs schedule()'s "preempt" parameter into rcu_note_context_switch(), which then records the Tasks RCU quiescent state, but only if this call to schedule() was -not- due to a preemption. To avoid adding overhead to the common-case context-switch path, this commit hides the rcu_note_context_switch() check under an existing non-common-case check. Suggested-by: Steven Rostedt Signed-off-by: Paul E. McKenney --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/sched') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3b31fc05a0f1..2adf7b6c04e7 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3378,7 +3378,7 @@ static void __sched notrace __schedule(bool preempt) hrtick_clear(rq); local_irq_disable(); - rcu_note_context_switch(); + rcu_note_context_switch(preempt); /* * Make sure that signal_pending_state()->signal_pending() below -- cgit v1.2.3-59-g8ed1b