From:   Yajun Deng <yajun.deng@linux.dev>
To:     mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
        vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
        rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
        bristot@redhat.com, vschneid@redhat.com
Cc:     linux-kernel@vger.kernel.org, Yajun Deng <yajun.deng@linux.dev>
Subject: [PATCH] sched/rt: Reset sysctl_sched_rr_timeslice when it non-positive
Date:   Tue, 14 Mar 2023 11:13:23 +0800
Message-Id: <20230314031323.3638994-1-yajun.deng@linux.dev>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When sysctl_sched_rr_timeslice was set a non-positive number, only
sched_rr_timeslice was reset to default, This behavior should let
users know.

So reset sysctl_sched_rr_timeslice at the same time when it
non-positive.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
 kernel/sched/rt.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 0a11f44adee5..0723a6297f96 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -3036,9 +3036,12 @@ static int sched_rr_handler(struct ctl_table *table, int write, void *buffer,
 	 * Also, writing zero resets the timeslice to default:
 	 */
 	if (!ret && write) {
-		sched_rr_timeslice =
-			sysctl_sched_rr_timeslice <= 0 ? RR_TIMESLICE :
-			msecs_to_jiffies(sysctl_sched_rr_timeslice);
+		if (sysctl_sched_rr_timeslice > 0)
+			sched_rr_timeslice = msecs_to_jiffies(sysctl_sched_rr_timeslice);
+		else {
+			sched_rr_timeslice = RR_TIMESLICE;
+			sysctl_sched_rr_timeslice = (MSEC_PER_SEC / HZ) * RR_TIMESLICE;
+		}
 	}
 	mutex_unlock(&mutex);
 
-- 
2.25.1