Re: [CFS Bandwidth Control v4 3/7] sched: throttle cfs_rq entitieswhich exceed their local quota

From: Balbir Singh
Date: Fri Feb 18 2011 - 01:52:50 EST


* Paul Turner <pjt@xxxxxxxxxx> [2011-02-15 19:18:34]:

> In account_cfs_rq_quota() (via update_curr()) we track consumption versus a
> cfs_rq's local quota and whether there is global quota available to continue
> enabling it in the event we run out.
>
> This patch adds the required support for the latter case, throttling entities
> until quota is available to run. Throttling dequeues the entity in question
> and sends a reschedule to the owning cpu so that it can be evicted.
>
> The following restrictions apply to a throttled cfs_rq:
> - It is dequeued from sched_entity hierarchy and restricted from being
> re-enqueued. This means that new/waking children of this entity will be
> queued up to it, but not past it.
> - It does not contribute to weight calculations in tg_shares_up
> - In the case that the cfs_rq of the cpu we are trying to pull from is throttled
> it is is ignored by the loadbalancer in __load_balance_fair() and
> move_one_task_fair().
>
> Signed-off-by: Paul Turner <pjt@xxxxxxxxxx>
> Signed-off-by: Nikhil Rao <ncrao@xxxxxxxxxx>
> Signed-off-by: Bharata B Rao <bharata@xxxxxxxxxxxxxxxxxx>


Acked-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>

--
Three Cheers,
Balbir
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