[PATCH 3.19 165/177] sched: Fix hrtick_start() on UP

From: Greg Kroah-Hartman
Date: Mon Mar 16 2015 - 10:19:42 EST

3.19-stable review patch. If anyone has any objections, please let me know.


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,

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/