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rcutorture: Preempt rather than block when testing task stalls

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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: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney 2021-05-16 21:17:27 -07:00
parent 25f6fa53a0
commit 59e8366628
1 changed files with 6 additions and 1 deletions
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7
kernel/rcu/rcutorture.c
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@ -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)