From owner-cvs-all  Wed Jun 27 23: 3:33 2001
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Date: Wed, 27 Jun 2001 23:03:24 -0700 (PDT)
From: John Baldwin <jhb@FreeBSD.org>
To: Matt Dillon <dillon@earth.backplane.com>
Subject: Re: cvs commit: src/sys/netinet tcp_input.c tcp_output.c tcp_sub
Cc: bmilekic@FreeBSD.org, jlemon@FreeBSD.org, cvs-all@FreeBSD.org,
	cvs-committers@FreeBSD.org, Mike Silbersack <silby@FreeBSD.org>,
	"Brian F. Feldman" <green@FreeBSD.org>,
	Jonathan Lemon Alfred Perlstein <bright@sneakerz.org>,
	Doug Rabson <dfr@nlsystems.com>
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On 28-Jun-01 Matt Dillon wrote:
>:Matt, I think you are forgetting that on BSD/OS, when a lightweight
>:ithread hits a held mutex, it then converts to a fully scheduled
>:heavyweight thread, at which point any kind of preemption you can think of
>:can happen.
>:...
>:Doug Rabson                           Mail:  dfr@nlsystems.com
> 
>     Yes, but that only applies to the interrupt thread, not the original
>     thread that was interrupted,

Wrong.  When the ithd that blocks does its fixup, it puts the interrupted
thread on the runqueue.

> and it doesn't happen at a random point...
>     it happens at a well defined point.

The thread is interrupted at a random point, not a well defined point. 
Interrupts are asynchronous and unpredicted by nature. :)

-- 

John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/
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"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/

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