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

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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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