2017-02-02 23:55 GMT+08:00 Peter Zijlstra <peterz@xxxxxxxxxxxxx>:
> On Tue, Jan 31, 2017 at 10:22:47AM -0700, Ross Zwisler wrote:
>> On Tue, Jan 31, 2017 at 4:48 AM, Mike Galbraith <efault@xxxxxx> wrote:
>> > On Tue, 2017-01-31 at 16:30 +0530, Sachin Sant wrote:
>
>
> Could some of you test this? It seems to cure things in my (very)
> limited testing.
>
Tested-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx>
> ---
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 96e4ccc..b773821 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -5609,7 +5609,7 @@ static void migrate_tasks(struct rq *dead_rq)
> {
> struct rq *rq = dead_rq;
> struct task_struct *next, *stop = rq->stop;
> - struct rq_flags rf, old_rf;
> + struct rq_flags rf;
> int dest_cpu;
>
> /*
> @@ -5628,7 +5628,9 @@ static void migrate_tasks(struct rq *dead_rq)
> * class method both need to have an up-to-date
> * value of rq->clock[_task]
> */
> + rq_pin_lock(rq, &rf);
> update_rq_clock(rq);
> + rq_unpin_lock(rq, &rf);
>
> for (;;) {
> /*
> @@ -5641,7 +5643,7 @@ static void migrate_tasks(struct rq *dead_rq)
> /*
> * pick_next_task assumes pinned rq->lock.
> */
> - rq_pin_lock(rq, &rf);
> + rq_repin_lock(rq, &rf);
> next = pick_next_task(rq, &fake_task, &rf);
> BUG_ON(!next);
> next->sched_class->put_prev_task(rq, next);
> @@ -5670,13 +5672,6 @@ static void migrate_tasks(struct rq *dead_rq)
> continue;
> }
>
> - /*
> - * __migrate_task() may return with a different
> - * rq->lock held and a new cookie in 'rf', but we need
> - * to preserve rf::clock_update_flags for 'dead_rq'.
> - */
> - old_rf = rf;
> -
> /* Find suitable destination for @next, with force if needed. */
> dest_cpu = select_fallback_rq(dead_rq->cpu, next);
>
> @@ -5685,7 +5680,6 @@ static void migrate_tasks(struct rq *dead_rq)
> raw_spin_unlock(&rq->lock);
> rq = dead_rq;
> raw_spin_lock(&rq->lock);
> - rf = old_rf;
> }
> raw_spin_unlock(&next->pi_lock);
> }
--
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