Date: Wed, 1 Dec 1999 15:39:28 -0800 (PST) From: Julian Elischer <julian@whistle.com> To: Archie Cobbs <archie@whistle.com> Cc: "Justin T. Gibbs" <gibbs@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern uipc_mbuf.c src/sys/sys mbuf.h Message-ID: <Pine.BSF.4.10.9912011538100.11380-100000@current1.whistle.com> In-Reply-To: <199912012327.PAA45003@bubba.whistle.com>
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basically it's not supposed to be in the hot path. It's for debugging and tracing utilities. On Wed, 1 Dec 1999, Archie Cobbs wrote: > Justin T. Gibbs writes: > > > Modified files: > > > sys/kern uipc_mbuf.c > > > sys/sys mbuf.h > > > Log: > > > The functions m_copym() and m_copypacket() return read-only copies, > > > because in the case of mbuf clusters they only increment the reference > > > count rather than actually copying the data. > > > > > > Add comments to this effect, and add a new routine called m_dup() that > > > returns a real, writable copy of an mbuf chain. > > > > How does this work in a 0 copy system? > > Not sure what a '0 copy system' is.. > > Basically all it does is create a completely new mbuf chain containing > the same data as the original. Definitely at least 1 copy :-) > > You rarely need this, but 'ipfw tee' is one of those cases. > > -Archie > > ___________________________________________________________________________ > Archie Cobbs * Whistle Communications, Inc. * http://www.whistle.com > > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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