On 4 November 2014 19:24, Wanpeng Li <[email protected]> wrote:
>
> On 14/11/4 下午7:13, pang.xunlei wrote:
>>
>> When selecting the cpu for a waking DL task, if curr is a non-DL
>> task which is bound only on this cpu, then we can give it a chance
>> to select a different cpu for this DL task to avoid curr starving.
>>
>> Signed-off-by: pang.xunlei <[email protected]>
>> ---
>> kernel/sched/deadline.c | 14 ++++++++++----
>> 1 file changed, 10 insertions(+), 4 deletions(-)
>>
>> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
>> index 7b0b2d2..1f64d4a 100644
>> --- a/kernel/sched/deadline.c
>> +++ b/kernel/sched/deadline.c
>> @@ -954,6 +954,9 @@ select_task_rq_dl(struct task_struct *p, int cpu, int
>> sd_flag, int flags)
>> struct task_struct *curr;
>> struct rq *rq;
>> + if (p->nr_cpus_allowed == 1)
>> + goto out;
>> +
>> if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
>> goto out;
>
>
> I don't think you use right branch of tip tree.
Hi Wanpeng, I'm using linux-3.18-rc3 as the base, does this have
something wrong? please point me out if any.
Thanks!
>
> Regards,
> Wanpeng Li
>
>> @@ -970,11 +973,14 @@ select_task_rq_dl(struct task_struct *p, int cpu,
>> int sd_flag, int flags)
>> * can!) we prefer to send it somewhere else. On the
>> * other hand, if it has a shorter deadline, we
>> * try to make it stay here, it might be important.
>> + *
>> + * If the current task on @p's runqueue is a non-DL task,
>> + * and this task is bound on current runqueue, then try to
>> + * see if we can wake this DL task up on a different runqueue,
>> */
>> - if (unlikely(dl_task(curr)) &&
>> - (curr->nr_cpus_allowed < 2 ||
>> - !dl_entity_preempt(&p->dl, &curr->dl)) &&
>> - (p->nr_cpus_allowed > 1)) {
>> + if (unlikely(curr->nr_cpus_allowed < 2) ||
>> + unlikely(dl_task(curr) &&
>> + !dl_entity_preempt(&p->dl, &curr->dl))) {
>> int target = find_later_rq(p);
>> if (target != -1)
>
>
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