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    SubjectRe: [PATCH 06/40] sched: add wakeup/sleep sched_notifiers and allow NULL notifier ops
    On Tue, 2010-01-19 at 17:28 +0900, Tejun Heo wrote:
    > Hello,
    > On 01/19/2010 10:04 AM, Tejun Heo wrote:
    > >> I'm thinking that we can place it next to activate_task(), if it makes
    > >> you feel better you can place them both at the end up ttwu_activate()
    > >> instead of in the middle.
    > >>
    > >> Esp. with the callback you have it really doesn't matter.
    > >
    > > Alright, if it's safe, there's no reason to keep it separate with an
    > > extra branch. I'll move it.
    > Alright, was trying to convert it and I'm still a bit worried. One of
    > the reasons I put it at the end of post_activation() is to allow
    > calling try_to_wake_up_local() from wakeup callback. This won't be
    > used by cmwq right now but making it symmetrical to sleep callback
    > would be more consistent, so... If we fire wakeup callback right
    > after activate_task() and allow try_to_wake_up_local() to be called
    > from it, wake up logic ends up being nested inside outer wake up which
    > is still in progress. Would that be safe too?

    I think so, still doing a wakeup from a wakeup sounds like trouble in
    that it has the potential to a thundering herd, so I'd really rather
    you'd not do something like that.

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      Last update: 2010-01-19 09:59    [W:0.019 / U:15.728 seconds]
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