Re: Question on when __pthread_lock second parameter shoudl be NULL

[Ulrich Drepper <drepper at redhat dot com>]

Kaz Kylheku <kaz@ashi.footprints.net> writes:

> > The only differnences in mutex.c that show up are in pthread_mutex_lock where
> > __pthread_lock is called with NULL as the second parameter for the FAST_NP and
> > with self for the ERRORCHECK mutexes and I was wondering why?
> 
> This is a performance bug. Because the pthread_mutex_lock() function acquires
> the self pointer, it should pass it down to __pthread_lock so that
> __pthread_lock doesn't have to make a redundant call to thread_self().
> 
> This issue still exists on the main trunk! Ulrich, can you commit a fix?

No no, look at the code.  If we actually get the self pointer we pass
it down.  In the case of PTHREAD_MUTEX_ADAPTIVE_NP we don't need self
in the mutex function and therefore pass NULL.

> Also, can we change the initializer for the main thread descriptor so that
> it directly initializes the p_errnop and p_h_errnop members with
> &_errno and &_h_errno, respectively? 

I'll try adding this.  But I'm not sure about the implications in the moment.

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