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From: Ivan Voras <ivoras@freebsd.org>
Date: Fri, 16 Aug 2013 11:38:44 +0200
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Subject: Re: svn commit: r254380 - in head/sys: kern sys
To: Colin Percival <cperciva@freebsd.org>
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> We have a single-writer / multiple-readers lock on *any particular byte*
> of a vnode.  The rangelock code is what keeps track of this, and the
> locking contention I was reducing was in the rangelock bookkeeping.

So, for example, if multiple processes or multiple threads read or
write a file somewhat unintelligently (a small file, operations on the
whole file, like in blogbench), they will effectively content for the
byte 0, right?