[PATCH tip/core/rcu 6/6] rcu: Make rcutorture fakewriters invoke rcu_barrier()

Paul E. McKenney
2012-06-15T18:58:48Z

From: "Paul E. McKenney" <paul.mckenney@linaro.org>

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>
---
kernel/rcutorture.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 54a3745..dfb4e20 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -1025,7 +1025,11 @@ rcu_torture_fakewriter(void *arg)
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) % (NR_CPUS * 8) == 0)
+ cur_ops->cb_barrier();
+ else
+ cur_ops->sync();
rcu_stutter_wait("rcu_torture_fakewriter");
} while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);

--
1.7.8