Re: [PATCH] MSVC: port pthread code to native Windows threads

From: Dmitry Potapov <dpotapov@gmail.com>
To: "Andrzej K. Haczewski" <ahaczewski@gmail.com>
Cc: Johannes Sixt <j.sixt@viscovery.net>, git@vger.kernel.org
Subject: Re: [PATCH] MSVC: port pthread code to native Windows threads
Date: Thu, 5 Nov 2009 16:48:58 +0300	[thread overview]
Message-ID: <20091105134858.GG27126@dpotapov.dyndns.org> (raw)
In-Reply-To: <16cee31f0911040547m69e5b9cbi30e20d2a7790bd6f@mail.gmail.com>

On Wed, Nov 04, 2009 at 02:47:09PM +0100, Andrzej K. Haczewski wrote:
> 2009/11/4 Johannes Sixt <j.sixt@viscovery.net>:
> 
> > - pthread_cond_signal is called while the mutex is held.
> 
> AFAIK that is a requirement for condition variable to be signaled
> while holding the same mutex that other threads cond_wait on. I just
> don't check that it is true, because Git is locking mutex.

There is no such requirement in POSIX:

   The pthread_cond_broadcast() or pthread_cond_signal() functions may
   be called by a thread whether or not it currently owns the mutex that
   threads calling pthread_cond_wait() or pthread_cond_timedwait() have
   associated with the condition variable during their waits; however,
   if predictable scheduling behavior is required, then that mutex shall
   be locked by the thread calling pthread_cond_broadcast() or
   pthread_cond_signal().

http://www.opengroup.org/onlinepubs/009695399/functions/pthread_cond_signal.html

Dmitry