Re: [ANNOUNCE] Linux 2.6 Real Time Kernel

[Vadim Lebedev]

Sven-Thorsten Dietrich <sdietrich@xxxxxxxxxx> wrote in message 
news:<2Nir3-4iC-13@xxxxxxxxxxxxxxxx>...
> Announcing the availability of prototype real-time (RT)
> enhancements to the Linux 2.6 kernel.

Reading the sources i believe that __p_mutex_up  is not constant time
operation because of __p_mutex_down....

It is clear that
__p_mutex_down is not constant time operation because of insertion
into the priority-sorted sleepers list.  However both __p_mutex_down
and __p_mutex_up are synchronize on the same global spinlock
(m_spin_lock) ....  so if the __p_mutex_down is holding this spinlock
while inserting NO other process(or) is able to perform any __p_mutex
operation...

Maybe the better idea would be to have a per-mutex spinlock? or even
better, given that the task->rt_priority have a finite range maybe each
mutex can have a table of sleeper lists indexed by rt_priority?


Vadim
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