diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-07-04 14:14:42 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-08-29 09:20:48 -0700 |
| commit | 444da518fd554eb1b9875dc97fac6ec249cee330 (patch) | |
| tree | 66b30935a20522ea61e26fba47184b15c8173737 /kernel/rcu/rcutorture.c | |
| parent | 31e7490741566d6f72be3a68bf9259a3bc2bc21d (diff) | |
rcutorture: Force occasional reader waits
Deferred quiescent states can interact with the scheduler, but
rcu_torture_reader() does not force such interaction all that frequently.
This commit therefore blocks for one jiffy after ten jiffies of read-side
runtime. This has the beneficial effect of being most likely to block
just after long-running readers, and it is exactly these readers that
are most likely to have been preempted (in CONFIG_PREEMPT=y kernels).
This in turn helps increase the probability that a deferred quiescent
state will be seen by RCU's context-switch hooks.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/rcutorture.c')
| -rw-r--r-- | kernel/rcu/rcutorture.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c index c596c6f1e457..50a4f0ed4ebf 100644 --- a/kernel/rcu/rcutorture.c +++ b/kernel/rcu/rcutorture.c @@ -1387,6 +1387,7 @@ static void rcu_torture_timer(struct timer_list *unused) static int rcu_torture_reader(void *arg) { + unsigned long lastsleep = jiffies; DEFINE_TORTURE_RANDOM(rand); struct timer_list t; @@ -1402,6 +1403,10 @@ rcu_torture_reader(void *arg) } if (!rcu_torture_one_read(&rand)) schedule_timeout_interruptible(HZ); + if (time_after(jiffies, lastsleep)) { + schedule_timeout_interruptible(1); + lastsleep = jiffies + 10; + } stutter_wait("rcu_torture_reader"); } while (!torture_must_stop()); if (irqreader && cur_ops->irq_capable) { |