Commit 353af9c9 authored Dec 20, 2012 by Paul Gortmaker Committed by Paul E. McKenney Jan 08, 2013

rcu: Prevent soft-lockup complaints about no-CBs CPUs



The wait_event() at the head of the rcu_nocb_kthread() can result in
soft-lockup complaints if the CPU in question does not register RCU
callbacks for an extended period.  This commit therefore changes
the wait_event() to a wait_event_interruptible().

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

parent d1c3ed66

kernel/rcutree_plugin.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -2366,10 +2366,11 @@ static int rcu_nocb_kthread(void *arg)
		for (;;) {
		/* If not polling, wait for next batch of callbacks. */
		if (!rcu_nocb_poll)
		wait_event(rdp->nocb_wq, rdp->nocb_head);
		wait_event_interruptible(rdp->nocb_wq, rdp->nocb_head);
		list = ACCESS_ONCE(rdp->nocb_head);
		if (!list) {
		schedule_timeout_interruptible(1);
		flush_signals(current);
		continue;
		}