[tip: core/rcu] rcutorture: Suppress boottime bad-sequence warnings

From: tip-bot2 for Paul E. McKenney
Date: Tue Mar 24 2020 - 05:16:48 EST


The following commit has been merged into the core/rcu branch of tip:

Commit-ID: 4ab00bdd99a906c089b5c20ee7b5cb91e7c61123
Gitweb: https://git.kernel.org/tip/4ab00bdd99a906c089b5c20ee7b5cb91e7c61123
Author: Paul E. McKenney <paulmck@xxxxxxxxxx>
AuthorDate: Thu, 05 Dec 2019 15:53:28 -08:00
Committer: Paul E. McKenney <paulmck@xxxxxxxxxx>
CommitterDate: Thu, 20 Feb 2020 16:03:30 -08:00

rcutorture: Suppress boottime bad-sequence warnings

In normal production, an excessively long wait on a grace period
(synchronize_rcu(), for example) at boottime is often just as bad
as at any other time. In fact, given the desire for fast boot, any
sort of long wait at boot is a bad idea. However, heavy rcutorture
testing on large hyperthreaded systems can generate such long waits
during boot as a matter of course. This commit therefore causes
the rcupdate.rcu_cpu_stall_suppress_at_boot kernel boot parameter to
suppress reporting of bootime bad-sequence warning due to excessively
long grace-period waits.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
kernel/rcu/rcutorture.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 16c84ec..5efd950 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1423,7 +1423,8 @@ rcu_torture_stats_print(void)
pr_alert("%s%s ", torture_type, TORTURE_FLAG);
pr_cont("rtc: %p %s: %lu tfle: %d rta: %d rtaf: %d rtf: %d ",
rcu_torture_current,
- rcu_torture_current ? "ver" : "VER",
+ rcu_torture_current && !rcu_stall_is_suppressed_at_boot()
+ ? "ver" : "VER",
rcu_torture_current_version,
list_empty(&rcu_torture_freelist),
atomic_read(&n_rcu_torture_alloc),