Commit 59e83666 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcutorture: Preempt rather than block when testing task stalls 



Currently, rcu_torture_stall() does a one-jiffy timed wait when
stall_cpu_block is set.  This works, but emits a pointless splat in
CONFIG_PREEMPT=y kernels.  This commit avoids this splat by instead
invoking preempt_schedule() in CONFIG_PREEMPT=y kernels.

This uses an admittedly ugly #ifdef, but abstracted approaches just
looked worse.  A prettier approach would provide a preempt_schedule()
definition with a WARN_ON() for CONFIG_PREEMPT=n kernels, but this seems
quite silly.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 25f6fa53

kernel/rcu/rcutorture.c

+6 −1
Original line number Diff line number Diff line
@@ -2022,8 +2022,13 @@ static int rcu_torture_stall(void *args) 
			  __func__, raw_smp_processor_id());

		while (ULONG_CMP_LT((unsigned long)ktime_get_seconds(),

				    stop_at))

			if (stall_cpu_block)

			if (stall_cpu_block) {

#ifdef CONFIG_PREEMPTION

				preempt_schedule();

#else

				schedule_timeout_uninterruptible(HZ);

#endif

			}

		if (stall_cpu_irqsoff)

			local_irq_enable();

		else if (!stall_cpu_block)