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SubjectRe: [PATCH 5/5] futex: fix miss ordered wakeups
On Thu, 12 Jun 2008, Daniel Walker wrote:

>
> On Thu, 2008-06-12 at 21:55 +0200, Thomas Gleixner wrote:
> > Also your interpretation of the POSIX requirement is very
> > questionable:
> >
> > "If there are threads blocked on the mutex object referenced by mutex
> > when pthread_mutex_unlock() is called, resulting in the mutex
> > becoming available, the scheduling policy shall determine which
> > thread shall acquire the mutex."
>
> The key is "scheduling policy" .. When the mutex is un-blocked the next
> task to run is the same as if the scheduler was selecting tasks from the
> list of blocked tasks .. For Linux, that means the highest priority
> tasks should be selected.. So it's no more acceptable for the scheduler
> to priority invert some tasks than it is for the futex to do it.

Sigh, when do you actually get a gripe that the default futex
implementation does not and can not guarantee that at all and therefor
your "correctness" patch is as important as a bag of rice which
toopled over in China ?

Provide answers to the real questions I asked more than once:

What's the real world problem ? Who cares about that - except you ?

Up to the point where you are actually able to come up with that
answers please direct your replies to /dev/null. That avoids that I
have to touch my .procmailrc.

Thanks,

tglx


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