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SubjectRe: [patch] sched/fair: Move se->vruntime normalization state into struct sched_entity
From
2016-05-23 17:40 GMT+08:00 Mike Galbraith <umgwanakikbuti@gmail.com>:
> On Mon, 2016-05-23 at 11:19 +0200, Peter Zijlstra wrote:
>> On Sun, May 22, 2016 at 09:00:01AM +0200, Mike Galbraith wrote:
>> > On Sat, 2016-05-21 at 21:00 +0200, Mike Galbraith wrote:
>> > > On Sat, 2016-05-21 at 16:04 +0200, Mike Galbraith wrote:
>> > >
>> > > > Wakees that were not migrated/normalized eat an unwanted min_vruntime,
>> > > > and likely take a size XXL latency hit. Big box running master bled
>> > > > profusely under heavy load until I turned TTWU_QUEUE off.
>> >
>> > May as well make it official and against master.today. Fly or die
>> > little patchlet.
>> >
>> > sched/fair: Move se->vruntime normalization state into struct sched_entity
>>
>> Does this work?
>
> Yup, bugs--. Kinda funny, I considered ~this way first, but thought
> you'd not that approach.. dang, got it back-assward ;-)
>

Nicer this one.

Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com>

>> ---
>> include/linux/sched.h | 1 +
>> kernel/sched/core.c | 18 +++++++++++-------
>> 2 files changed, 12 insertions(+), 7 deletions(-)
>>
>> diff --git a/include/linux/sched.h b/include/linux/sched.h
>> index 1b43b45a22b9..a2001e01b3df 100644
>> --- a/include/linux/sched.h
>> +++ b/include/linux/sched.h
>> @@ -1534,6 +1534,7 @@ struct task_struct {
>> unsigned sched_reset_on_fork:1;
>> unsigned sched_contributes_to_load:1;
>> unsigned sched_migrated:1;
>> + unsigned sched_remote_wakeup:1;
>> unsigned :0; /* force alignment to the next boundary */
>>
>> /* unserialized, strictly 'current' */
>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>> index 404c0784b1fc..7f2cae4620c7 100644
>> --- a/kernel/sched/core.c
>> +++ b/kernel/sched/core.c
>> @@ -1768,13 +1768,15 @@ void sched_ttwu_pending(void)
>> cookie = lockdep_pin_lock(&rq->lock);
>>
>> while (llist) {
>> + int wake_flags = 0;
>> +
>> p = llist_entry(llist, struct task_struct,
>> wake_entry);
>> llist = llist_next(llist);
>> - /*
>> - * See ttwu_queue(); we only call
>> ttwu_queue_remote() when
>> - * its a x-cpu wakeup.
>> - */
>> - ttwu_do_activate(rq, p, WF_MIGRATED, cookie);
>> +
>> + if (p->sched_remote_wakeup)
>> + wake_flags = WF_MIGRATED;
>> +
>> + ttwu_do_activate(rq, p, wake_flags, cookie);
>> }
>>
>> lockdep_unpin_lock(&rq->lock, cookie);
>> @@ -1819,10 +1821,12 @@ void scheduler_ipi(void)
>> irq_exit();
>> }
>>
>> -static void ttwu_queue_remote(struct task_struct *p, int cpu)
>> +static void ttwu_queue_remote(struct task_struct *p, int cpu, int
>> wake_flags)
>> {
>> struct rq *rq = cpu_rq(cpu);
>>
>> + p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
>> +
>> if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) {
>> if (!set_nr_if_polling(rq->idle))
>> smp_send_reschedule(cpu);
>> @@ -1869,7 +1873,7 @@ static void ttwu_queue(struct task_struct *p,
>> int cpu, int wake_flags)
>> #if defined(CONFIG_SMP)
>> if (sched_feat(TTWU_QUEUE) &&
>> !cpus_share_cache(smp_processor_id(), cpu)) {
>> sched_clock_cpu(cpu); /* sync clocks x-cpu */
>> - ttwu_queue_remote(p, cpu);
>> + ttwu_queue_remote(p, cpu, wake_flags);
>> return;
>> }
>> #endif



--
Regards,
Wanpeng Li

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