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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
	josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
	rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
	fweisbec@gmail.com, oleg@redhat.com,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 05/20] rcutorture: Preempt RCU-preempt readers more vigorously
Date: Fri,  1 Dec 2017 12:08:50 -0800
Message-ID: <1512158945-27269-5-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <20171201200819.GA25519@linux.vnet.ibm.com>

This commit attempts to make a very rare rcutorture failure happen
more often by increasing the fraction of RCU-preempt read-side critical
sections that are preempted.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/rcu/rcutorture.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 61fb95612125..2e810443975d 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -316,7 +316,7 @@ static void rcu_read_delay(struct torture_random_state *rrsp)
 	if (!(torture_random(rrsp) % (nrealreaders * 2 * shortdelay_us)))
 		udelay(shortdelay_us);
 	if (!preempt_count() &&
-	    !(torture_random(rrsp) % (nrealreaders * 20000)))
+	    !(torture_random(rrsp) % (nrealreaders * 500)))
 		torture_preempt_schedule();  /* QS only if preemptible. */
 }
 
-- 
2.5.2

  parent reply index

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-01 20:08 [PATCH tip/core/rcu 0/20] Torture-test updates for v4.16 Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 01/20] torture: Suppress CPU stall warnings during shutdown ftrace dump Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 02/20] torture: Prepare scripting for shift from %p to %pK Paul E. McKenney
2017-12-04 12:32   ` David Laight
2017-12-04 13:42     ` Paul E. McKenney
2017-12-04 14:13       ` David Laight
2017-12-04 16:11         ` Paul E. McKenney
2017-12-10 12:52           ` Andy Shevchenko
2017-12-10 18:51             ` Paul E. McKenney
2017-12-10 20:39             ` Linus Torvalds
2017-12-10 21:47               ` Paul E. McKenney
2017-12-11 19:59                 ` Kees Cook
2017-12-12 16:08                   ` Paul E. McKenney
     [not found]               ` <87wp1sa55h.fsf@concordia.ellerman.id.au>
     [not found]                 ` <CA+55aFxHdAX_ztDMUyXihhUv_eftntHecGUUaV3qAtGj_ZbKCg@mail.gmail.com>
2017-12-13 12:59                   ` Long live %pK (was Re: [PATCH tip/core/rcu 02/20] torture: Prepare scripting for shift from %p to %pK) Michael Ellerman
2017-12-13 18:21                     ` Linus Torvalds
2017-12-01 20:08 ` [PATCH tip/core/rcu 03/20] rcutorture: Change printk() %p to %pK Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 04/20] torture: Reduce #ifdefs for preempt_schedule() Paul E. McKenney
2017-12-01 20:08 ` Paul E. McKenney [this message]
2017-12-01 20:08 ` [PATCH tip/core/rcu 06/20] rcutorture/configinit: Fix build directory error message Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 07/20] rcutorture: Remove unused script, config2frag.sh Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 08/20] rcutorture/kvm.sh: Remove unused variable, `alldone` Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 09/20] rcutorture/kvm.sh: Use consistent help text for --qemu-args Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 10/20] rcutorture/kvm.sh: Support execution from any directory Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 11/20] rcutorture/kvm-recheck-*: Improve result directory readability check Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 12/20] rcutorture: Simplify logging Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 13/20] rcutorture: Simplify functions.sh include path Paul E. McKenney
2017-12-01 20:08 ` [PATCH tip/core/rcu 14/20] rcutorture/kvm-build.sh: Skip build directory check Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 15/20] torture: Place all torture-test modules in one MAINTAINERS group Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 16/20] locking/locktorture: Fix rwsem reader_delay Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 17/20] locking/locktorture: Fix num reader/writer corner cases Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 18/20] torture: Make stutter less vulnerable to compilers and races Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 19/20] torture: Eliminate torture_runnable and perf_runnable Paul E. McKenney
2017-12-01 20:09 ` [PATCH tip/core/rcu 20/20] torture: Save a line in stutter_wait(): while -> for Paul E. McKenney

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