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rcutorture: Print forward-progress test interval on error

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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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-07-24 20:50:40 -07:00
parent c04dd09bd3
commit f4de46ed5b
1 changed files with 9 additions and 5 deletions
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14
kernel/rcu/rcutorture.c
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@ -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;
}