Commit c5e0cb3d authored Oct 28, 2009 by Lai Jiangshan Committed by Ingo Molnar Nov 02, 2009

rcu: Cleanup: balance rcu_irq_enter()/rcu_irq_exit() calls



Currently, rcu_irq_exit() is invoked only for CONFIG_NO_HZ,
while rcu_irq_enter() is invoked unconditionally.  This patch
moves rcu_irq_exit() out from under CONFIG_NO_HZ so that the
calls are balanced.

This patch has no effect on the behavior of the kernel because
both rcu_irq_enter() and rcu_irq_exit() are empty for
!CONFIG_NO_HZ, but the code is easier to understand if the calls
are obviously balanced in all cases.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <12567428891605-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 2c28e245

kernel/softirq.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -302,9 +302,9 @@ void irq_exit(void)
	if (!in_interrupt() && local_softirq_pending())		if (!in_interrupt() && local_softirq_pending())
	invoke_softirq();		invoke_softirq();

			rcu_irq_exit();
	#ifdef CONFIG_NO_HZ		#ifdef CONFIG_NO_HZ
	/* Make sure that timer wheel updates are propagated */		/* Make sure that timer wheel updates are propagated */
	rcu_irq_exit();
	if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched())		if (idle_cpu(smp_processor_id()) && !in_interrupt() && !need_resched())
	tick_nohz_stop_sched_tick(0);		tick_nohz_stop_sched_tick(0);
	#endif		#endif

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