4.4-stable review patch. If anyone has any objections, please let me know.
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From: Xunlei Pang xlpang@redhat.com
commit ae83b56a56f8d9643dedbee86b457fa1c5d42f59 upstream.
When a contrained task is throttled by dl_check_constrained_dl(), it may carry the remaining positive runtime, as a result when dl_task_timer() fires and calls replenish_dl_entity(), it will not be replenished correctly due to the positive dl_se->runtime.
This patch assigns its runtime to 0 if positive after throttling.
Signed-off-by: Xunlei Pang xlpang@redhat.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Acked-by: Daniel Bristot de Oliveira bristot@redhat.com Cc: Juri Lelli juri.lelli@arm.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Luca Abeni luca.abeni@santannapisa.it Cc: Mike Galbraith efault@gmx.de Cc: Peter Zijlstra peterz@infradead.org Cc: Steven Rostedt rostedt@goodmis.org Cc: Thomas Gleixner tglx@linutronix.de Fixes: df8eac8cafce ("sched/deadline: Throttle a constrained deadline task activated after the deadline) Link: http://lkml.kernel.org/r/1494421417-27550-1-git-send-email-xlpang@redhat.com Signed-off-by: Ingo Molnar mingo@kernel.org Cc: Ben Hutchings ben.hutchings@codethink.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/sched/deadline.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -732,6 +732,8 @@ static inline void dl_check_constrained_ if (unlikely(dl_se->dl_boosted || !start_dl_timer(p))) return; dl_se->dl_throttled = 1; + if (dl_se->runtime > 0) + dl_se->runtime = 0; } }