Commit ae83b56a authored May 10, 2017 by Xunlei Pang Committed by Ingo Molnar Jun 08, 2017

sched/deadline: Zero out positive runtime after throttling constrained tasks



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: df8eac8c ("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>

parent ccc9d651

kernel/sched/deadline.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -941,6 +941,8 @@ static inline void dl_check_constrained_dl(struct sched_dl_entity *dl_se)
		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;
		}
		}

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