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Subject: Re: [RFC][PATCH 05/22] sched: SCHED_DEADLINE policy implementation
From: Peter Zijlstra <peterz@infradead.org>
To: Raistlin <raistlin@linux.it>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
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Date: Wed, 10 Nov 2010 21:21:18 +0100
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On Fri, 2010-10-29 at 08:30 +0200, Raistlin wrote:
> +static void update_dl_entity(struct sched_dl_entity *dl_se)
> +{
> +       struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
> +       struct rq *rq = rq_of_dl_rq(dl_rq);
> +
> +       /*
> +        * The arrival of a new instance needs special treatment, i.e.,
> +        * the actual scheduling parameters have to be "renewed".
> +        */
> +       if (dl_se->dl_new) {
> +               setup_new_dl_entity(dl_se);
> +               return;
> +       }
> +
> +       if (dl_time_before(dl_se->deadline, rq->clock) ||
> +           dl_entity_overflow(dl_se, rq->clock)) {
> +               dl_se->deadline = rq->clock + dl_se->dl_deadline;
> +               dl_se->runtime = dl_se->dl_runtime;
> +       }
> +} 

Can't we loose runtime deficit this way?