Re: [patch 11/15] sched: prevent interactions between throttled entitiesand load-balance

From: Hidetoshi Seto
Date: Tue May 10 2011 - 03:27:19 EST


(2011/05/03 18:28), Paul Turner wrote:
>>From the perspective of load-balance and shares distribution, throttled
> entities should be invisible.
>
> However, both of these operations work on 'active' lists and are not
> inherently aware of what group hierarchies may be present. In some cases this
> may be side-stepped (e.g. we could sideload via tg_load_down in load balance)
> while in others (e.g. update_shares()) it is more difficult to compute without
> incurring some O(n^2) costs.
>
> Instead, track hierarchal throttled state at time of transition. This allows

hierarchical

> us to easily identify whether an entity belongs to a throttled hierarchy and
> avoid incorrect interactions with it.
>
> Also, when an entity leaves a throttled hierarchy we need to advance its
> time averaging for shares averaging so that the elapsed throttled time is not
> considered as part of the cfs_rq's operation.
>
> Signed-off-by: Paul Turner <pjt@xxxxxxxxxx>
> ---

Reviewed-by: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>

Thanks,
H.Seto

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