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From: Brad Pepers <brad@linuxcanada.com>
Organization: Linux Canada Inc.
To: dipankar@in.ibm.com
Subject: Re: Multi-threading
Date: Mon, 11 Mar 2002 16:53:45 -0700
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On Monday 11 March 2002 12:36, Dipankar Sarma wrote:
> In article <20020311182111Z310364-889+120750@vger.kernel.org> Brad Pepers 
wrote:
> > There was a message posted by Jim Starkey about his experiences using
> > threads on Linux and the problems debugging them.  It came down to two
> > things:
> >
> > 2. Linux is missing an atomic use-count mechanism which returns values
> > like the Microsoft InterlockedIncrement/Decrement functions do.
>
> Can't this be done using atomic_dec_and_test() and the likes ?
> Google tells me that windoze InterlockedIncrement/Decrement stuff
> does the almost same thing. Why can't refcounting be
> implemented using just atomic_inc/dec and/or atomic_inc/dec_and_test ?

The atomic_dec_and_test certainly handles the most often used case and is 
good enough.  Apparently it would be nice to have the value back sometimes 
too though.

The atomic_inc_and_test is not much good though since the case you most often 
want to track is the 0 to 1 transition and not -1 to 0!

-- 
Brad Pepers
brad@linuxcanada.com
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