Messages in this thread |  | | From | Odin Ugedal <> | Date | Sat, 29 May 2021 11:33:32 +0200 | Subject | Re: [PATCH 2/3] sched/fair: Correctly insert cfs_rq's to list on unthrottle |
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Hi,
> normally tg_load_avg_contrib should be null when cfs_rq_is_decayed()
Yeah, I think that is an ok assumption of how it _should_ work (given the other patches in flight are merged).
> The reason of this list is to ensure that the load of all cfs_rq are > periodically updated as it is then used to share the runtime between > groups so we should keep to use the rule whenever possible.
Yeah, right.
> we probably need to keep (cfs_rq->nr_running >= 1) as we can have case > where tg_load_avg_contrib is null but a task is enqueued
Yeah, there is probably a chance of enqueuing a task without any load, and then a parent gets throttled. So (cfs_rq->tg_load_avg_contrib || cfs_rq->nr_running) is probably the way to go if we want to avoid a new field. Will resend a patch with that instead.
In case the new field is the main issue with the original solution, we could also change the on_list int to have three modes like; NO, YES, THROTTLED/PAUSED, but that would require a bigger rewrite of the other logic, so probably outside the scope of this patch.
Thanks Odin
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