rcutorture: Vary forward-progress test interval

Some of the Linux kernel's RCU implementations provide several mechanisms
to promote forward progress that operate over different timeframes.
This commit therefore causes rcu_torture_fwd_prog() to vary the duration
of its forward-progress testing in order to test each such mechanism.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-07-19 13:07:20 -07:00
parent 152f4afbfd
commit 08a7a2ec68

View File

@ -1676,16 +1676,21 @@ static int rcu_torture_fwd_prog(void *args)
unsigned long cver;
unsigned long gps;
int idx;
int sd;
int sd4;
unsigned long stopat;
bool tested = false;
int tested_tries = 0;
static DEFINE_TORTURE_RANDOM(trs);
VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
do {
schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
cver = READ_ONCE(rcu_torture_current_version);
gps = cur_ops->get_gp_seq();
stopat = jiffies + cur_ops->stall_dur() / fwd_progress_div;
sd = cur_ops->stall_dur() + 1;
sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
stopat = jiffies + sd4 + torture_random(&trs) % (sd - sd4);
while (time_before(jiffies, stopat) && !torture_must_stop()) {
idx = cur_ops->readlock();
udelay(10);