This is a note to let you know that I've just added the patch titled
sched/rt: sysctl_sched_rr_timeslice show default timeslice after reset
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-rt-sysctl_sched_rr_timeslice-show-default-timeslice-after-reset.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From stable+bounces-23366-greg=kroah.com@xxxxxxxxxxxxxxx Thu Feb 22 18:06:37 2024
From: Petr Vorel <pvorel@xxxxxxx>
Date: Thu, 22 Feb 2024 18:05:39 +0100
Subject: sched/rt: sysctl_sched_rr_timeslice show default timeslice after reset
To: stable@xxxxxxxxxxxxxxx
Cc: Cyril Hrubis <chrubis@xxxxxxx>, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, Sasha Levin <sashal@xxxxxxxxxx>, Ingo Molnar <mingo@xxxxxxxxxx>, Peter Zijlstra <peterz@xxxxxxxxxxxxx>, Petr Vorel <pvorel@xxxxxxx>, Mel Gorman <mgorman@xxxxxxx>
Message-ID: <20240222170540.1375962-2-pvorel@xxxxxxx>
From: Cyril Hrubis <chrubis@xxxxxxx>
[ Upstream commit c1fc6484e1fb7cc2481d169bfef129a1b0676abe ]
The sched_rr_timeslice can be reset to default by writing value that is
<= 0. However after reading from this file we always got the last value
written, which is not useful at all.
$ echo -1 > /proc/sys/kernel/sched_rr_timeslice_ms
$ cat /proc/sys/kernel/sched_rr_timeslice_ms
-1
Fix this by setting the variable that holds the sysctl file value to the
jiffies_to_msecs(RR_TIMESLICE) in case that <= 0 value was written.
Signed-off-by: Cyril Hrubis <chrubis@xxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Petr Vorel <pvorel@xxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxx>
Tested-by: Petr Vorel <pvorel@xxxxxxx>
Link: https://lore.kernel.org/r/20230802151906.25258-3-chrubis@xxxxxxx
Signed-off-by: Petr Vorel <pvorel@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/sched/rt.c | 3 +++
1 file changed, 3 insertions(+)
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -2735,6 +2735,9 @@ int sched_rr_handler(struct ctl_table *t
sched_rr_timeslice =
sysctl_sched_rr_timeslice <= 0 ? RR_TIMESLICE :
msecs_to_jiffies(sysctl_sched_rr_timeslice);
+
+ if (sysctl_sched_rr_timeslice <= 0)
+ sysctl_sched_rr_timeslice = jiffies_to_msecs(RR_TIMESLICE);
}
mutex_unlock(&mutex);
Patches currently in stable-queue which might be from kroah.com@xxxxxxxxxxxxxxx are
queue-4.19/sched-rt-disallow-writing-invalid-values-to-sched_rt_period_us.patch
queue-4.19/sched-rt-fix-sysctl_sched_rr_timeslice-intial-value.patch
queue-4.19/sched-rt-sysctl_sched_rr_timeslice-show-default-timeslice-after-reset.patch
