Re: [REPOST] RFC: sched: Prevent wakeup to enter critical section needlessly

[Andi Kleen]

Ivo Sieben <meltedpianoman@xxxxxxxxx> writes:

> Check the waitqueue task list to be non empty before entering the critical
> section. This prevents locking the spin lock needlessly in case the queue
> was empty, and therefor also prevent scheduling overhead on a PREEMPT_RT
> system.
>
> Signed-off-by: Ivo Sieben <meltedpianoman@xxxxxxxxx>
> ---
>
>  REPOST:
>  Request for comments:
>  - Does this make any sense?

Looks good to me. Avoiding any spinlock is good.  I don't even think you
need "careful", if you miss an update it was just as it happened a
little later.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only
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