Commit 7b6c1648 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Uladzislau Rezki (Sony)
Browse files

rcutorture: Use finer-grained timeouts for rcu_torture_writer() polling 



The rcu_torture_writer() polling currently uses timeouts ranging from
zero to 16 milliseconds to wait for the polled grace period to end.
This works, but it would be better to have a higher probability of
exercising races with the code that cleans up after a grace period.
This commit therefore switches from these millisecond-scale timeouts
to timeouts ranging from zero to 128 microseconds, and with a full
microsecond's worth of timeout fuzz.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarUladzislau Rezki (Sony) <urezki@gmail.com>
parent 579a05da

kernel/rcu/rcutorture.c

+8 −8
Original line number Diff line number Diff line
@@ -1561,7 +1561,7 @@ rcu_torture_writer(void *arg) 
							break;

						}

					WARN_ON_ONCE(ulo_size > 0 && i >= ulo_size);

					torture_hrtimeout_jiffies(torture_random(&rand) % 16,

					torture_hrtimeout_us(torture_random(&rand) % 128, 1000,

							     &rand);

				}

				rcu_torture_pipe_update(old_rp);
@@ -1582,7 +1582,7 @@ rcu_torture_writer(void *arg) 
							break;

						}

					WARN_ON_ONCE(rgo_size > 0 && i >= rgo_size);

					torture_hrtimeout_jiffies(torture_random(&rand) % 16,

					torture_hrtimeout_us(torture_random(&rand) % 128, 1000,

							     &rand);

				}

				rcu_torture_pipe_update(old_rp);
@@ -1592,7 +1592,7 @@ rcu_torture_writer(void *arg) 
				gp_snap = cur_ops->start_gp_poll_exp();

				rcu_torture_writer_state = RTWS_POLL_WAIT_EXP;

				while (!cur_ops->poll_gp_state_exp(gp_snap))

					torture_hrtimeout_jiffies(torture_random(&rand) % 16,

					torture_hrtimeout_us(torture_random(&rand) % 128, 1000,

							     &rand);

				rcu_torture_pipe_update(old_rp);

				break;
@@ -1601,7 +1601,7 @@ rcu_torture_writer(void *arg) 
				cur_ops->start_gp_poll_exp_full(&gp_snap_full);

				rcu_torture_writer_state = RTWS_POLL_WAIT_EXP_FULL;

				while (!cur_ops->poll_gp_state_full(&gp_snap_full))

					torture_hrtimeout_jiffies(torture_random(&rand) % 16,

					torture_hrtimeout_us(torture_random(&rand) % 128, 1000,

							     &rand);

				rcu_torture_pipe_update(old_rp);

				break;