Commit f4de46ed authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcutorture: Print forward-progress test interval on error 



This commit prints the duration of the forward-progress test interval in
the case that no forward progress was observed as an aid to debugging.
When forward progress does happen, it prints out the number of
rcu_torture_writer() versions and grace periods that elapsed during the
forward-progress test.  At the end of the run, it also prints the number
of attempted and actual forward-progress tests.

Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent c04dd09b

kernel/rcu/rcutorture.c

+9 −5
Original line number Diff line number Diff line
@@ -1702,6 +1702,7 @@ static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp) 
static int rcu_torture_fwd_prog(void *args)

{

	unsigned long cver;

	unsigned long dur;

	struct fwd_cb_state fcs = { .stop = 0 };

	unsigned long gps;

	int idx;
@@ -1709,7 +1710,7 @@ static int rcu_torture_fwd_prog(void *args) 
	int sd4;

	bool selfpropcb = false;

	unsigned long stopat;

	bool tested = false;

	int tested = 0;

	int tested_tries = 0;

	static DEFINE_TORTURE_RANDOM(trs);
@@ -1727,7 +1728,8 @@ static int rcu_torture_fwd_prog(void *args) 
		gps = cur_ops->get_gp_seq();

		sd = cur_ops->stall_dur() + 1;

		sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;

		stopat = jiffies + sd4 + torture_random(&trs) % (sd - sd4);

		dur = sd4 + torture_random(&trs) % (sd - sd4);

		stopat = jiffies + dur;

		while (time_before(jiffies, stopat) && !torture_must_stop()) {

			idx = cur_ops->readlock();

			udelay(10);
@@ -1737,10 +1739,11 @@ static int rcu_torture_fwd_prog(void *args) 
		}

		tested_tries++;

		if (!time_before(jiffies, stopat) && !torture_must_stop()) {

			tested = true;

			cver = cver == READ_ONCE(rcu_torture_current_version);

			tested++;

			cver = READ_ONCE(rcu_torture_current_version) - cver;

			gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);

			WARN_ON_ONCE(cver && gps < 2);

			WARN_ON(!cver && gps < 2);

			pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps);

		}

		/* Avoid slow periods, better to test when busy. */

		stutter_wait("rcu_torture_fwd_prog");
@@ -1754,6 +1757,7 @@ static int rcu_torture_fwd_prog(void *args) 
	}

	/* Short runs might not contain a valid forward-progress attempt. */

	WARN_ON(!tested && tested_tries >= 5);

	pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);

	torture_kthread_stopping("rcu_torture_fwd_prog");

	return 0;

}

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