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From:   Frederic Weisbecker <frederic@kernel.org>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     "Paul E. McKenney" <paulmck@kernel.org>,
        Boqun Feng <boqun.feng@gmail.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Josh Triplett <josh@joshtriplett.org>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Neeraj Upadhyay <neeraj.upadhyay@amd.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Uladzislau Rezki <urezki@gmail.com>, rcu <rcu@vger.kernel.org>,
        Frederic Weisbecker <frederic@kernel.org>
Subject: [PATCH 01/23] torture: Share torture_random_state with torture_shuffle_tasks()
Date:   Tue, 10 Oct 2023 13:58:59 +0200
Message-Id: <20231010115921.988766-2-frederic@kernel.org>
In-Reply-To: <20231010115921.988766-1-frederic@kernel.org>
References: <20231010115921.988766-1-frederic@kernel.org>
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From: "Paul E. McKenney" <paulmck@kernel.org>

Both torture_shuffle_tasks() and its caller torture_shuffle()
define a torture_random_state structure.  This is suboptimal given
that torture_shuffle_tasks() runs for a very short period of time.
This commit therefore causes torture_shuffle() to pass a pointer to its
torture_random_state structure down to torture_shuffle_tasks().

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
---
 kernel/torture.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/torture.c b/kernel/torture.c
index b28b05bbef02..68dba4ecab5c 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -520,9 +520,8 @@ static void torture_shuffle_task_unregister_all(void)
  * A special case is when shuffle_idle_cpu = -1, in which case we allow
  * the tasks to run on all CPUs.
  */
-static void torture_shuffle_tasks(void)
+static void torture_shuffle_tasks(struct torture_random_state *trp)
 {
-	DEFINE_TORTURE_RANDOM(rand);
 	struct shuffle_task *stp;
 
 	cpumask_setall(shuffle_tmp_mask);
@@ -543,7 +542,7 @@ static void torture_shuffle_tasks(void)
 
 	mutex_lock(&shuffle_task_mutex);
 	list_for_each_entry(stp, &shuffle_task_list, st_l) {
-		if (!random_shuffle || torture_random(&rand) & 0x1)
+		if (!random_shuffle || torture_random(trp) & 0x1)
 			set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
 	}
 	mutex_unlock(&shuffle_task_mutex);
@@ -562,7 +561,7 @@ static int torture_shuffle(void *arg)
 	VERBOSE_TOROUT_STRING("torture_shuffle task started");
 	do {
 		torture_hrtimeout_jiffies(shuffle_interval, &rand);
-		torture_shuffle_tasks();
+		torture_shuffle_tasks(&rand);
 		torture_shutdown_absorb("torture_shuffle");
 	} while (!torture_must_stop());
 	torture_kthread_stopping("torture_shuffle");
@@ -673,7 +672,7 @@ int torture_shutdown_init(int ssecs, void (*cleanup)(void))
 	if (ssecs > 0) {
 		shutdown_time = ktime_add(ktime_get(), ktime_set(ssecs, 0));
 		return torture_create_kthread(torture_shutdown, NULL,
-					     shutdown_task);
+					      shutdown_task);
 	}
 	return 0;
 }
-- 
2.34.1