Commit-ID: 295d6d5e373607729bcc8182c25afe964655714f
Gitweb: https://git.kernel.org/tip/295d6d5e373607729bcc8182c25afe964655714f
Author: Luca Abeni <luca.ab...@santannapisa.it>
AuthorDate: Thu, 7 Sep 2017 12:09:29 +0200
Committer: Ingo Molnar <mi...@kernel.org>
CommitDate: Tue, 10 Oct 2017 11:43:30 +0200
sched/deadline: Fix switching to -deadline
Fix a bug introduced in:
72f9f3fdc928 ("sched/deadline: Remove dl_new from struct sched_dl_entity")
After that commit, when switching to -deadline if the scheduling
deadline of a task is in the past then switched_to_dl() calls
setup_new_entity() to properly initialize the scheduling deadline
and runtime.
The problem is that the task is enqueued _before_ having its parameters
initialized by setup_new_entity(), and this can cause problems.
For example, a task with its out-of-date deadline in the past will
potentially be enqueued as the highest priority one; however, its
adjusted deadline may not be the earliest one.
This patch fixes the problem by initializing the task's parameters before
enqueuing it.
Signed-off-by: luca abeni <luca.ab...@santannapisa.it>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bris...@redhat.com>
Cc: Juri Lelli <juri.le...@arm.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poir...@linaro.org>
Cc: Mike Galbraith <efa...@gmx.de>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Link:
http://lkml.kernel.org/r/1504778971-13573-3-git-send-email-luca.ab...@santannapisa.it
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
kernel/sched/deadline.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 0191ec7..9d45354 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1364,6 +1364,10 @@ enqueue_dl_entity(struct sched_dl_entity *dl_se,
update_dl_entity(dl_se, pi_se);
} else if (flags & ENQUEUE_REPLENISH) {
replenish_dl_entity(dl_se, pi_se);
+ } else if ((flags & ENQUEUE_RESTORE) &&
+ dl_time_before(dl_se->deadline,
+ rq_clock(rq_of_dl_rq(dl_rq_of_se(dl_se))))) {
+ setup_new_dl_entity(dl_se);
}
__enqueue_dl_entity(dl_se);
@@ -2255,13 +2259,6 @@ static void switched_to_dl(struct rq *rq, struct
task_struct *p)
return;
}
- /*
- * If p is boosted we already updated its params in
- * rt_mutex_setprio()->enqueue_task(..., ENQUEUE_REPLENISH),
- * p's deadline being now already after rq_clock(rq).
- */
- if (dl_time_before(p->dl.deadline, rq_clock(rq)))
- setup_new_dl_entity(&p->dl);
if (rq->curr != p) {
#ifdef CONFIG_SMP
