4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Xunlei Pang <xlp...@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 <xlp...@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Acked-by: Daniel Bristot de Oliveira <bris...@redhat.com>
Cc: Juri Lelli <juri.le...@arm.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Luca Abeni <luca.ab...@santannapisa.it>
Cc: Mike Galbraith <efa...@gmx.de>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Thomas Gleixner <t...@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-xlp...@redhat.com
Signed-off-by: Ingo Molnar <mi...@kernel.org>
Cc: Ben Hutchings <ben.hutchi...@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gre...@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;
}
}
