[PATCH AUTOSEL 5.2 094/123] sched/deadline: Fix double accounting of rq/running bw in push & pull

[Sasha Levin]

From: Dietmar Eggemann <dietmar.eggem...@arm.com>

[ Upstream commit f4904815f97a934258445a8f763f6b6c48f007e7 ]

{push,pull}_dl_task() always calls {de,}activate_task() with .flags=0
which sets p->on_rq=TASK_ON_RQ_MIGRATING.

{push,pull}_dl_task()->{de,}activate_task()->{de,en}queue_task()->
{de,en}queue_task_dl() calls {sub,add}_{running,rq}_bw() since
p->on_rq==TASK_ON_RQ_MIGRATING.
So {sub,add}_{running,rq}_bw() in {push,pull}_dl_task() is
double-accounting for that task.

Fix it by removing rq/running bw accounting in [push/pull]_dl_task().

Fixes: 7dd778841164 ("sched/core: Unify p->on_rq updates")
Signed-off-by: Dietmar Eggemann <dietmar.eggem...@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Cc: Valentin Schneider <valentin.schnei...@arm.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Luca Abeni <luca.ab...@santannapisa.it>
Cc: Daniel Bristot de Oliveira <bris...@redhat.com>
Cc: Juri Lelli <juri.le...@redhat.com>
Cc: Qais Yousef <qais.you...@arm.com>
Link: https://lkml.kernel.org/r/20190802145945.18702-2-dietmar.eggem...@arm.com
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 kernel/sched/deadline.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 43901fa3f2693..1c66480afda81 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -2088,17 +2088,13 @@ static int push_dl_task(struct rq *rq)
        }
 
        deactivate_task(rq, next_task, 0);
-       sub_running_bw(&next_task->dl, &rq->dl);
-       sub_rq_bw(&next_task->dl, &rq->dl);
        set_task_cpu(next_task, later_rq->cpu);
-       add_rq_bw(&next_task->dl, &later_rq->dl);
 
        /*
         * Update the later_rq clock here, because the clock is used
         * by the cpufreq_update_util() inside __add_running_bw().
         */
        update_rq_clock(later_rq);
-       add_running_bw(&next_task->dl, &later_rq->dl);
        activate_task(later_rq, next_task, ENQUEUE_NOCLOCK);
        ret = 1;
 
@@ -2186,11 +2182,7 @@ static void pull_dl_task(struct rq *this_rq)
                        resched = true;
 
                        deactivate_task(src_rq, p, 0);
-                       sub_running_bw(&p->dl, &src_rq->dl);
-                       sub_rq_bw(&p->dl, &src_rq->dl);
                        set_task_cpu(p, this_cpu);
-                       add_rq_bw(&p->dl, &this_rq->dl);
-                       add_running_bw(&p->dl, &this_rq->dl);
                        activate_task(this_rq, p, 0);
                        dmin = p->dl.deadline;
 
-- 
2.20.1