From: "Paul E. McKenney" <paulmck@kernel.org>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
rostedt@goodmis.org, "Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH rcu 25/25] rcutorture: Limit read-side polling-API testing
Date: Wed, 31 Aug 2022 11:12:10 -0700 [thread overview]
Message-ID: <20220831181210.2695080-25-paulmck@kernel.org> (raw)
In-Reply-To: <20220831181207.GA2694717@paulmck-ThinkPad-P17-Gen-1>
RCU's polled grace-period API is reasonably lightweight, but still
contains heavyweight memory barriers. This commit therefore limits
testing of this API from rcutorture's readers in order to avoid the
false negatives that these heavyweight operations could provoke.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/rcutorture.c | 41 +++++++++++++++++++++++------------------
1 file changed, 23 insertions(+), 18 deletions(-)
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index fe1836aad6466..91103279d7b4f 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1903,6 +1903,7 @@ rcutorture_loop_extend(int *readstate, struct torture_random_state *trsp,
*/
static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
{
+ bool checkpolling = !(torture_random(trsp) & 0xfff);
unsigned long cookie;
struct rcu_gp_oldstate cookie_full;
int i;
@@ -1920,10 +1921,12 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
WARN_ON_ONCE(!rcu_is_watching());
newstate = rcutorture_extend_mask(readstate, trsp);
rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
- if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
- cookie = cur_ops->get_gp_state();
- if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
- cur_ops->get_gp_state_full(&cookie_full);
+ if (checkpolling) {
+ if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
+ cookie = cur_ops->get_gp_state();
+ if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
+ cur_ops->get_gp_state_full(&cookie_full);
+ }
started = cur_ops->get_gp_seq();
ts = rcu_trace_clock_local();
p = rcu_dereference_check(rcu_torture_current,
@@ -1957,20 +1960,22 @@ static bool rcu_torture_one_read(struct torture_random_state *trsp, long myid)
}
__this_cpu_inc(rcu_torture_batch[completed]);
preempt_enable();
- if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
- WARN_ONCE(cur_ops->poll_gp_state(cookie),
- "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
- __func__,
- rcu_torture_writer_state_getname(),
- rcu_torture_writer_state,
- cookie, cur_ops->get_gp_state());
- if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
- WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
- "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
- __func__,
- rcu_torture_writer_state_getname(),
- rcu_torture_writer_state,
- cpumask_pr_args(cpu_online_mask));
+ if (checkpolling) {
+ if (cur_ops->get_gp_state && cur_ops->poll_gp_state)
+ WARN_ONCE(cur_ops->poll_gp_state(cookie),
+ "%s: Cookie check 2 failed %s(%d) %lu->%lu\n",
+ __func__,
+ rcu_torture_writer_state_getname(),
+ rcu_torture_writer_state,
+ cookie, cur_ops->get_gp_state());
+ if (cur_ops->get_gp_state_full && cur_ops->poll_gp_state_full)
+ WARN_ONCE(cur_ops->poll_gp_state_full(&cookie_full),
+ "%s: Cookie check 6 failed %s(%d) online %*pbl\n",
+ __func__,
+ rcu_torture_writer_state_getname(),
+ rcu_torture_writer_state,
+ cpumask_pr_args(cpu_online_mask));
+ }
rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
WARN_ON_ONCE(readstate);
// This next splat is expected behavior if leakpointer, especially
--
2.31.1.189.g2e36527f23
prev parent reply other threads:[~2022-08-31 18:16 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 18:12 [PATCH rcu 0/7] Polled grace-period updates for v6.1 Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 01/25] rcu: Add full-sized polling for get_completed*() and poll_state*() Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 02/25] rcu: Add full-sized polling for get_state() Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 03/25] rcutorture: Abstract synchronous and polled API testing Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 04/25] rcutorture: Allow per-RCU-flavor polled double-GP check Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 05/25] rcutorture: Verify RCU reader prevents full polling from completing Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 06/25] rcutorture: Remove redundant RTWS_DEF_FREE check Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 07/25] rcutorture: Verify long-running reader prevents full polling from completing Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 08/25] rcu: Add full-sized polling for start_poll() Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 09/25] rcu: Add full-sized polling for start_poll_expedited() Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 10/25] rcu: Remove blank line from poll_state_synchronize_rcu() docbook header Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 11/25] rcu: Add full-sized polling for cond_sync_full() Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 12/25] rcu: Add full-sized polling for cond_sync_exp_full() Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 13/25] rcu: Disable run-time single-CPU grace-period optimization Paul E. McKenney
2022-08-31 18:11 ` [PATCH rcu 14/25] rcu: Set rcu_data structures' initial ->gpwrap value to true Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 15/25] rcu-tasks: Remove grace-period fast-path rcu-tasks helper Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 16/25] rcu: Make synchronize_rcu() fast path update ->gp_seq counters Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 17/25] rcu: Remove expedited grace-period fast-path forward-progress helper Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 18/25] rcu: Make synchronize_rcu_expedited() fast path update .expedited_sequence Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 19/25] rcu: Remove ->rgos_polled field from rcu_gp_oldstate structure Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 20/25] rcutorture: Adjust rcu_poll_need_2gp() for rcu_gp_oldstate field removal Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 21/25] rcu: Make synchronize_rcu() fastpath update only boot-CPU counters Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 22/25] rcutorture: Use 1-suffixed variable in rcu_torture_write_types() check Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 23/25] rcutorture: Expand rcu_torture_write_types() first "if" statement Paul E. McKenney
2022-08-31 18:12 ` [PATCH rcu 24/25] rcu: Add functions to compare grace-period state values Paul E. McKenney
2022-08-31 18:12 ` Paul E. McKenney [this message]
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