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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-04-11 15:50:41 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-04-21 05:59:27 -0700
commitbcbfdd01dce5556a952fae84ef16fd0f12525e7b (patch)
treed674b23e7a573c6e5234acb5e914fc60e581594a /kernel/rcu/update.c
parent0497b489b8255054f113fd31faeb72f6dbc50a68 (diff)
downloadlwn-bcbfdd01dce5556a952fae84ef16fd0f12525e7b.tar.gz
lwn-bcbfdd01dce5556a952fae84ef16fd0f12525e7b.zip
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 <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/update.c')
-rw-r--r--kernel/rcu/update.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index c5df0d756900..273e869ca21d 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -665,6 +665,7 @@ static void check_holdout_task(struct task_struct *t,
put_task_struct(t);
return;
}
+ rcu_request_urgent_qs_task(t);
if (!needreport)
return;
if (*firstreport) {