Re: [PATCH] 2.6.16 - futex: small optimization (?)

[Pierre PEIFFER]

Eric Dumazet a écrit :
> I think your analysis is correct Pierre, but you speak of 
> 'task-switches', where there is only a spinlock involved :
>
> On UP case : a wake_up_all() wont preempt current thread : it will 
> task-switch only when current thread exits kernel mode.
>
> On PREEMPT case : wake_up_all() wont preempt current thread (because 
> current thread is holding bh->lock).
>
> On SMP : the awaken thread will spin some time on bh->lock, but not 
> task-switch again.

Ok, yes, you're right, thanks.

> On RT kernel, this might be different of course...

So, I confirm it only happens on RT kernel ...
... but my patch does not work on those kernels :-/

In fact, I don't really see what's wrong ?

--
Pierre

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