From: paulmck@kernel.org
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, kernel-team@fb.com,
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, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 3/4] locktorture: Use private random-number generators
Date: Fri, 14 Feb 2020 16:03:36 -0800 [thread overview]
Message-ID: <20200215000337.14667-3-paulmck@kernel.org> (raw)
In-Reply-To: <20200215000312.GA14585@paulmck-ThinkPad-P72>
From: "Paul E. McKenney" <paulmck@kernel.org>
Both lock_torture_writer() and lock_torture_reader() use the "static"
keyword on their DEFINE_TORTURE_RANDOM(rand) declarations, which means
that a single instance of a random-number generator are shared among all
the writers and another is shared among all the readers. Unfortunately,
this random-number generator was not designed for concurrent access.
This commit therefore removes both "static" keywords so that each reader
and each writer gets its own random-number generator.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/locking/locktorture.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 687c1d8..5baf904 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -618,7 +618,7 @@ static struct lock_torture_ops percpu_rwsem_lock_ops = {
static int lock_torture_writer(void *arg)
{
struct lock_stress_stats *lwsp = arg;
- static DEFINE_TORTURE_RANDOM(rand);
+ DEFINE_TORTURE_RANDOM(rand);
VERBOSE_TOROUT_STRING("lock_torture_writer task started");
set_user_nice(current, MAX_NICE);
@@ -655,7 +655,7 @@ static int lock_torture_writer(void *arg)
static int lock_torture_reader(void *arg)
{
struct lock_stress_stats *lrsp = arg;
- static DEFINE_TORTURE_RANDOM(rand);
+ DEFINE_TORTURE_RANDOM(rand);
VERBOSE_TOROUT_STRING("lock_torture_reader task started");
set_user_nice(current, MAX_NICE);
--
2.9.5
next prev parent reply other threads:[~2020-02-15 0:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-15 0:03 [PATCH tip/core/rcu 0/4] Lock torture-test updates for v5.7 Paul E. McKenney
2020-02-15 0:03 ` [PATCH tip/core/rcu 1/4] locktorture: Print ratio of acquisitions, not failures paulmck
2020-02-15 0:03 ` [PATCH tip/core/rcu 2/4] locktorture: Allow CPU-hotplug to be disabled via --bootargs paulmck
2020-02-15 0:03 ` paulmck [this message]
2020-02-15 0:03 ` [PATCH tip/core/rcu 4/4] locktorture: Forgive apparent unfairness if CPU hotplug paulmck
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