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Date: Wed, 16 Apr 2008 17:12:07 -0700
From: Julian Elischer <julian@elischer.org>
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To: "Murty, Ravi" <ravi.murty@intel.com>
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Cc: freebsd-hackers@freebsd.org
Subject: Re: md_spinlock_count?
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Murty, Ravi wrote:
> Hello All,
> 
>  
> 
> I was looking at the code that creates a new process (fork) with a
> single thread coming out on the other side. I can't figure out a couple
> of things.
> 
>  
> 
> 1.	Why is the md_spinlock_count for the new thread set to 1 and not
> to 0. This happens in cpu_fork and cpu_set_upcall under the amd64 tree. 
> 2.	If this was the "per-cpu" idle thread and the AP was booting up
> (running init_secondary) why does it grab sched_lock and call
> spinlock_exit. It would seem simpler to set the count of the idle thread
> to 0 and not have to call spinlock_exit. The only answer I can come up
> with is the fact that a non-zero spinlock_count prevents interrupts from
> getting disabled/renabled to some unknown value? 

Which version/branch?
(and a filename and linenumber would be good too)
You might make it easy for us to answer you :-)

> 
>  
> 
> Thanks
> 
> Ravi Murty
> 
>  
> 
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