Commit-ID: 7c590fcca66b58957f8e34acdb0587cd1eeed35b
Gitweb: https://git.kernel.org/tip/7c590fcca66b58957f8e34acdb0587cd1eeed35b
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
AuthorDate: Tue, 7 Aug 2018 16:42:42 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Wed, 29 Aug 2018 09:20:48 -0700
rcutorture: Maintain self-propagating CB only during forward-progress test
The current forward-progress testing maintains a self-propagating
callback during the full test. This could result in false negatives
for stutter-end checking, where it might appear that RCU was clearing
out old callbacks only because it was being continually motivated by
the self-propagating callback. This commit therefore shuts down the
self-propagating callback at the end of each forward-progress test
interval.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/rcutorture.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index ae10ad531993..a02a2f21386b 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1706,7 +1706,7 @@ static int rcu_torture_fwd_prog(void *args)
{
unsigned long cver;
unsigned long dur;
- struct fwd_cb_state fcs = { .stop = 0 };
+ struct fwd_cb_state fcs;
unsigned long gps;
int idx;
int sd;
@@ -1722,11 +1722,14 @@ static int rcu_torture_fwd_prog(void *args)
set_user_nice(current, MAX_NICE);
if (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) {
init_rcu_head_on_stack(&fcs.rh);
- cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
selfpropcb = true;
}
do {
schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
+ if (selfpropcb) {
+ WRITE_ONCE(fcs.stop, 0);
+ cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
+ }
cver = READ_ONCE(rcu_torture_current_version);
gps = cur_ops->get_gp_seq();
sd = cur_ops->stall_dur() + 1;
@@ -1748,13 +1751,15 @@ static int rcu_torture_fwd_prog(void *args)
WARN_ON(!cver && gps < 2);
pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps);
}
+ if (selfpropcb) {
+ WRITE_ONCE(fcs.stop, 1);
+ cur_ops->sync(); /* Wait for running CB to complete. */
+ cur_ops->cb_barrier(); /* Wait for queued callbacks. */
+ }
/* Avoid slow periods, better to test when busy. */
stutter_wait("rcu_torture_fwd_prog");
} while (!torture_must_stop());
if (selfpropcb) {
- WRITE_ONCE(fcs.stop, 1);
- cur_ops->sync(); /* Wait for running callback to complete. */
- cur_ops->cb_barrier(); /* Wait for queued callbacks. */
WARN_ON(READ_ONCE(fcs.stop) != 2);
destroy_rcu_head_on_stack(&fcs.rh);
}
|