From owner-freebsd-hackers  Tue Mar 26 21:22:51 2002
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Date: Tue, 26 Mar 2002 21:21:57 -0800
From: Terry Lambert <tlambert2@mindspring.com>
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To: Alfred Perlstein <bright@mu.org>
Cc: Andrew <andrew@ugh.net.au>, Dan Nelson <dnelson@allantgroup.com>,
	Volker Stolz <stolz@hyperion.informatik.rwth-aachen.de>,
	Ian <freebsd@damnhippie.dyndns.org>, hackers@FreeBSD.ORG
Subject: Re: idprio
References: <3CA0D3FE.8113515C@mindspring.com> <20020327092520.V24232-100000@starbug.ugh.net.au> <20020326223103.GC93885@elvis.mu.org>
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Alfred Perlstein wrote:
> > But if system calls aren't preempted under what circumstances can a
> > process hold a vnode lock and then be usurped for processor?
> 
> While sleeping for IO.

Ideal systems release and reacquire locks when they are going
to suspend for a long time (Djikstra's "Banker's Algorithm").

-- Terry

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