This is a note to let you know that I've just added the patch titled
sched: Fix hrtick_start() on UP
to the 3.19-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-fix-hrtick_start-on-up.patch
and it can be found in the queue-3.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 868933359a3bdda25b562e9d41bce7071edc1b08 Mon Sep 17 00:00:00 2001
From: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
Date: Wed, 26 Nov 2014 08:44:06 +0800
Subject: sched: Fix hrtick_start() on UP
From: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
commit 868933359a3bdda25b562e9d41bce7071edc1b08 upstream.
The commit 177ef2a6315e ("sched/deadline: Fix a precision problem in
the microseconds range") forgot to change the UP version of
hrtick_start(), do so now.
Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
Fixes: 177ef2a6315e ("sched/deadline: Fix a precision problem in the microseconds range")
[ Fixed the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxx>
Cc: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1416962647-76792-7-git-send-email-wanpeng.li@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/sched/core.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -490,6 +490,11 @@ static __init void init_hrtick(void)
*/
void hrtick_start(struct rq *rq, u64 delay)
{
+ /*
+ * Don't schedule slices shorter than 10000ns, that just
+ * doesn't make sense. Rely on vruntime for fairness.
+ */
+ delay = max_t(u64, delay, 10000LL);
__hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
HRTIMER_MODE_REL_PINNED, 0);
}
Patches currently in stable-queue which might be from wanpeng.li@xxxxxxxxxxxxxxx are
queue-3.19/sched-fix-hrtick_start-on-up.patch
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