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Date: Wed, 27 Aug 2008 16:44:07 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-core] [RFC][PATCH 2/3] Switch to handle-based fast
	mutex owners
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To: Jan Kiszka <jan.kiszka@domain.hid>
Cc: xenomai-core <xenomai@xenomai.org>

Jan Kiszka wrote:
> Gilles Chanteperdrix wrote:
>> Jan Kiszka wrote:
>>> To improve robustness of the fast mutex implementation in POSIX (and
>>> later on in native), it is better to track the mutex owner by handle
>>> instead of kernel object pointer. Therefore, this patch changes
>>> __xn_sys_current (xeno_set_current) so that it returns
>>> xnthread_handle(current_thread). It furthermore converts the POSIX mutex
>>> implementation to pick up and store the lock owner as handle in the
>>> kernel/user-shared mutex. Finally it ensures that at least POSIX threads
>>> always have an (anonymous) handle assigned.
>>>
>>> As the value stored in the mutex variable is now an integer, we can
>>> switch over to xnarch_atomic_t, removing all atomic_intptr users.
>> Ok. I do not know if this should be part of this patch, or in another
>> one, but we should call xeno_set_current in the trampolines of all
>> skins, so that they can use the native and posix mutexes.
>>
>> This is another thing that I have left in a state of flux...
> 
> Find it below (PATCH 4/3).
> 
> BTW, should we better invoke pthread_exit in xeno_set_current in case of 
> a failure?

I prefer my application to die. This way I would know that something
went wrong. And by the way, how could this syscall fail ? I mean if
xenomai or the posix skin are not loaded, we would have known it earlier.

-- 
                                                 Gilles.