Messages in this thread | | | Subject | Re: [PATCH 06/40] sched: add wakeup/sleep sched_notifiers and allow NULL notifier ops | From | Peter Zijlstra <> | Date | Tue, 19 Jan 2010 09:55:02 +0100 |
| |
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.
| |