Messages in this thread | | | Date | Wed, 28 Oct 2015 17:57:10 -0700 | From | Olav Haugan <> | Subject | Re: [PATCH] sched: Update task->on_rq when tasks are moving between runqueues |
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On 15-10-25 11:09:24, Peter Zijlstra wrote: > On Sat, Oct 24, 2015 at 11:01:02AM -0700, Olav Haugan wrote: > > Task->on_rq has three states: > > 0 - Task is not on runqueue (rq) > > 1 (TASK_ON_RQ_QUEUED) - Task is on rq > > 2 (TASK_ON_RQ_MIGRATING) - Task is on rq but in the process of being > > migrated to another rq > > > > When a task is moving between rqs task->on_rq state should be > > TASK_ON_RQ_MIGRATING > > Only when not holding both rq locks..
IMHO I think we should keep the state of p->on_rq updated with the correct state all the time unless I am incorrect in what p->on_rq represent. The task is moving between rq's and is on the rq so the state should be TASK_ON_RQ_MIGRATING right? I do realize that the code is currently not broken. However, in the future someone might come along and change set_task_cpu() and the code change might rely on an accurate p->on_rq value. It would be good design to keep this value correct.
Thanks,
-- .Olav
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