Re: [PATCH 2/3 v2] futex: avoid double wake up in futex_wake() on -RT

[Davidlohr Bueso]

On Fri, 2015-04-10 at 18:11 +0200, Sebastian Andrzej Siewior wrote:
> This patch delays the wakeup of the process untill
						^^^ until

>  the hb->lock is
> dropped to avoid boosting + context switch to obtain the lock.

Doing the wakeups while holding the lock is also a general performance
issue for futex_wake. The problem being dealing with spurious wakeups
(wacky drivers), which makes no difference wrt nr_wake.

Thanks,
Davidlohr

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/