rcu: Make rcutorture fakewriters invoke rcu_barrier()
The current rcutorture rcu_barrier() testing never intentionally runs
more than one instance of rcu_barrier() at a given time. This fails
to test the the shiny new concurrency features of rcu_barrier(). This
commit therefore modifies the rcutorture fakewriter kthread to randomly
invoke rcu_barrier() rather than the usual synchronize_rcu().
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 045a3dc..c279ee9 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -1025,7 +1025,11 @@
do {
schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
udelay(rcu_random(&rand) & 0x3ff);
- cur_ops->sync();
+ if (cur_ops->cb_barrier != NULL &&
+ rcu_random(&rand) % (nfakewriters * 8) == 0)
+ cur_ops->cb_barrier();
+ else
+ cur_ops->sync();
rcu_stutter_wait("rcu_torture_fakewriter");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);