Re: [PATCH 09/10] sched: task_sched_runtime introduce micro optimization

[KOSAKI Motohiro]

> Stronger:
> 
> +#ifdef CONFIG_64BIT
> +       if (!p->on_cpu)
> +               return p->se.sum_exec_runtime;
> +#endif
> 
> [ Or !p->on_cpu || !add_delta ].
> 
> We can take the racy read versus p->on_cpu since:
>   If we race with it leaving cpu: we take lock, we're correct
>   If we race with it entering cpu: unaccounted time ---> 0, this is
> indistinguishable from the read occurring a few cycles earlier.

OK, agreed. That's nice.


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