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Date:	Wed, 10 Mar 2010 10:59:29 +0100
From:	Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To:	cygwin AT cygwin DOT com
Subject:	Re: Cygwin 1.7: Concurrency Issue with Shared State Initialization
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On Mar 10 10:55, Schmidt, Oliver wrote:
> Hi Corrina,
> 
> Thanks for your involvement :-)
> 
> >> [...] a spinlock [...] With
> >> InterlockedCompareExchange() and Sleep() it should be quite simple to
> >> create one that's very efficient in the usual scenario.
> 
> > Does the below patch fix this for you?
> 
> I'll test the snapshot asap!
> 
> [...]
> +      LONG init = InterlockedCompareExchange (&installation_root_init, 1L, 0L);
> [...]
> +	  low_priority_sleep (0);
> [...]
> 
> I see we were thinking along the same lines ;-)

The final patch is from cgf.  It's probably more performant since it
drops the requirement for an additional spinlock.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

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