Messages in this thread | | | Date | Thu, 23 Feb 2017 10:50:50 +0100 | From | Peter Zijlstra <> | Subject | Re: min_vruntime update when a task is sleeping/migrating |
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On Thu, Feb 23, 2017 at 11:45:26AM +0530, Pavan Kondeti wrote: > Hi Peter, > > The comment and the code around 2nd update_min_vruntime() call in > dequeue_entity() are not matching. If I understand commit b60205c7c558 > ("sched/fair: Fix min_vruntime tracking") correctly, the check is > inverted there. We want to update min_vruntime when a task is > sleeping/migrating. is my understanding right?
Hurm, yes that comment and the code are not in agreement :/
Having gone over the code again, I think the comment is right and the code is wrong, but it would be good to double check that.
> static void > dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > { > > <snip> > /* > * Now advance min_vruntime if @se was the entity holding it back, > * except when: DEQUEUE_SAVE && !DEQUEUE_MOVE, in this case we'll be > * put back on, and if we advance min_vruntime, we'll be placed back > * further than we started -- ie. we'll be penalized. > */ > if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) == DEQUEUE_SAVE) > update_min_vruntime(cfs_rq); > }
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