lkml.org 
[lkml]   [2014]   [Nov]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v5] sched/deadline: support dl task migration during cpu hotplug
Hi Peter,
On Wed, Nov 12, 2014 at 04:39:06PM +0100, Peter Zijlstra wrote:
>On Wed, Nov 12, 2014 at 03:08:44PM +0000, Juri Lelli wrote:
>> > @@ -1185,8 +1223,9 @@ static int find_later_rq(struct task_struct *task)
>> > * We have to consider system topology and task affinity
>> > * first, then we can look for a suitable cpu.
>> > */
>> > - cpumask_copy(later_mask, task_rq(task)->rd->span);
>> > - cpumask_and(later_mask, later_mask, cpu_active_mask);
>> > + cpumask_copy(later_mask, cpu_active_mask);
>> > + if (likely(task_rq(task)->online))
>> > + cpumask_and(later_mask, later_mask, task_rq(task)->rd->span);
>>
>> So, here you consider the span only when the task_rq is online,
>> but there might be others cpus still online belonging to the same
>> rd->span. And you have to consider them when migrating. Actually,
>> migration must still be restricted to the online cpus of task's
>> original rd->span, or I fear you can break clustered scheduling.
>
>Ah, good point that, we must somehow find the right root domain to
>'restore' the task to. Now I'm not entirely sure we still have this.
>Lemme ponder that.

Any idea is a great appreciated. :-)

Regards,
Wanpeng Li


\
 
 \ /
  Last update: 2014-11-13 00:41    [W:0.093 / U:0.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site