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authorWanpeng Li <wanpeng.li@linux.intel.com>2014-11-26 01:44:01 +0100
committerIngo Molnar <mingo@kernel.org>2015-02-04 07:52:25 +0100
commita7bebf488791aa1036f3e6629daf01d01f705dcb (patch)
tree5a85ca285a7e66581e8f97094bafac7cfa5b02cc /kernel/sched
parentMerge branch 'sched/urgent' into sched/core, to merge fixes before applying n... (diff)
downloadlinux-a7bebf488791aa1036f3e6629daf01d01f705dcb.tar.xz
linux-a7bebf488791aa1036f3e6629daf01d01f705dcb.zip
sched/deadline: Fix hrtick for a non-leftmost task
After update_curr_dl() the current task might not be the leftmost task anymore. In that case do not start a new hrtick for it. In this case NEED_RESCHED will be set and the next schedule will start the hrtick for the new task if and when appropriate. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Acked-by: Juri Lelli <juri.lelli@arm.com> [ Rewrote the changelog and comment. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Kirill Tkhai <ktkhai@parallels.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1416962647-76792-2-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/deadline.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index e0e9c2986976..7b684f9341a5 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1073,7 +1073,13 @@ static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued)
{
update_curr_dl(rq);
- if (hrtick_enabled(rq) && queued && p->dl.runtime > 0)
+ /*
+ * Even when we have runtime, update_curr_dl() might have resulted in us
+ * not being the leftmost task anymore. In that case NEED_RESCHED will
+ * be set and schedule() will start a new hrtick for the next task.
+ */
+ if (hrtick_enabled(rq) && queued && p->dl.runtime > 0 &&
+ is_leftmost(p, &rq->dl))
start_hrtick_dl(rq, p);
}