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Date: Sun, 21 Feb 2010 13:21:10 +0800
From: David Xu <davidxu@freebsd.org>
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To: Konstantin Belousov <kib@freebsd.org>
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Cc: src-committers@freebsd.org, svn-src-user@freebsd.org
Subject: Re: svn commit: r204132 - in user/kib/vm6/sys: conf dev/md kern sys
 ufs/ffs ufs/ufs vm
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Konstantin Belousov wrote:
> Author: kib
> Date: Sat Feb 20 16:34:42 2010
> New Revision: 204132
> URL: http://svn.freebsd.org/changeset/base/204132
> 
> Log:
>   Implementation of range locking for i/o and vm i/o.
>   
>   First vm_readwrite.c implementation by:	jeff
>   In collaboration with:	pho
The range locking is confusing, if there are thread A,B and C,
if A reads range 0-100, B writes range 0-100, C reads 200-300,
why should C waits before B is guaranteed ? C should be able to freely
read its data.

Regards,
David Xu