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From: John Baldwin <jhb@freebsd.org>
To: John Birrell <jb@freebsd.org>
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Cc: Perforce Change Reviews <perforce@freebsd.org>
Subject: Re: PERFORCE change 100025 for review
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On Monday 26 June 2006 01:37, John Birrell wrote:
> http://perforce.freebsd.org/chv.cgi?CH=100025
> 
> Change 100025 by jb@jb_freebsd2 on 2006/06/26 05:37:23
> 
> 	The use of FreeBSD's semaphores here creates scheduler instability.
> 	This device needs a clean path from the timer interrupt.
> 	
> 	For the time being, since I'm only working on single processor
> 	systems, comment out the semaphore calls. When I get access to a 
> 	multi-cpu machine, I'll need to implement a simple semaphore system
> 	for use here.

The only thing you can use from the timer interrupt is a spin mutex as far
as synchronization primitives.  Note that you can provide sleep/wakeup
via msleep_spin() and wakeup() + wakeup_one().

-- 
John Baldwin