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    SubjectRe: [RFC PATCH v3 00/16] Core scheduling v3
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    On 2019/8/12 23:38, Vineeth Remanan Pillai wrote:
    >> I have two other small changes that I think are worth sending out.
    >>
    >> The first simplify logic in pick_task() and the 2nd avoid task pick all
    >> over again when max is preempted. I also refined the previous hack patch to
    >> make schedule always happen only for root cfs rq. Please see below for
    >> details, thanks.
    >>
    > I see a potential issue here. With the simplification in pick_task,
    > you might introduce a livelock where the match logic spins for ever.
    > But you avoid that with the patch 2, by removing the loop if a pick
    > preempts max. The potential problem is that, you miss a case where
    > the newly picked task might have a match in the sibling on which max
    > was selected before. By selecting idle, you ignore the potential match.

    Oh that's right, I missed this.

    > As of now, the potential match check does not really work because,
    > sched_core_find will always return the same task and we do not check
    > the whole core_tree for a next match. This is in my TODO list to have
    > sched_core_find to return the best next match, if match was preempted.
    > But its a bit complex and needs more thought.

    Sounds worth to do :-)

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