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To: Doug Rabson <dfr@nlsystems.com>
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From: Peter A Jonsson <pj@ludd.ltu.se>
Date: 19 Feb 2004 17:26:23 +0100
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Subject: Re: Read Copy Update
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> I imagine that a FreeBSD implementation of RCU wouldn't actually be too
> hard and it might be well worth it as an alternative way of managing
> concurrency, e.g. for the routing cache and the name cache (and probably
> lots of other things).

Alan Cox pointed out[1] that there was a patent problem (US Patent
#05442758 [2]) with RCU which prevented inclusion in the Linux
kernel. This was solved[3] by granting the right to use it in GPL
software according to my understanding. Isn't this a problem for
FreeBSD?

[1] http://www.cs.helsinki.fi/linux/linux-kernel/2001-36/0385.html
[2]
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=5442758.WKU.&OS=PN/5442758&RS=PN/5442758
[3] http://www.cs.helsinki.fi/linux/linux-kernel/2001-36/0505.html

/ Peter