On 12 May 2017 at 15:16, Tejun Heo <t...@kernel.org> wrote: > Hello, Vincent. > > On Thu, May 11, 2017 at 09:02:22AM +0200, Vincent Guittot wrote: >> Sorry, what i mean is: >> When the group entity of a cfs_rq is enqueued, we are sure that either >> the parents is already enqueued or it will be enqueued in the same >> sequence. We must be sure that no other branch will be enqueued in the >> middle of the sequence and will reset tmp_alone_branch. >> This is true with current implementation but I wondered it can happen >> if we del/add the cfs_rq out of order >> >> That said i haven't find a use case that break the sequence > > Hmm... a cfs_rq can be removed from leaf list iff it's empty and > dequeued, and enqueueing is always from top down. If an ancestor is > already enqueued, it's guaranteed to be on the leaf list; otherwise, > it's guaranteed to be enqueued beforehand and thus put on the leaf > list too. I think it should be fine.
I agree FWIW Acked-by: Vincent Guittot <vincent.guit...@linaro.org> > > Thanks. > > -- > tejun
