From owner-freebsd-net Sun Aug 27 14:50:14 2000 Delivered-To: freebsd-net@freebsd.org Received: from salmon.maths.tcd.ie (salmon.maths.tcd.ie [134.226.81.11]) by hub.freebsd.org (Postfix) with SMTP id 4BF1337B423; Sun, 27 Aug 2000 14:50:12 -0700 (PDT) Received: from lanczos.maths.tcd.ie by salmon.maths.tcd.ie with SMTP id ; 27 Aug 2000 22:50:11 +0100 (BST) Date: Sun, 27 Aug 2000 22:50:11 +0100 From: David Malone To: Archie Cobbs Cc: freebsd-net@freebsd.org, freebsd-current@freebsd.org Subject: Re: Proposal to clarify mbuf handling rules Message-ID: <20000827225011.A10714@lanczos.maths.tcd.ie> References: <200008272125.OAA66159@bubba.whistle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <200008272125.OAA66159@bubba.whistle.com>; from archie@whistle.com on Sun, Aug 27, 2000 at 02:25:55PM -0700 Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Sun, Aug 27, 2000 at 02:25:55PM -0700, Archie Cobbs wrote: > What do people think? If this is generally agreeable I'll try to > work on putting together a patch set for review. Myself and Ian Dowse have been talking about almost this issue recently in relation to sbcompress. At the moment sbcompress is too conservative about compressing mbuf chains, with the result that it is easily possible to run many machines out of mbuf clusters. (We've seen this problem with netscape and kioslave). At the moment sbcompress only compresses into mbufs, where it could also compress into clusters, providing they have a reference count of 1. However, this still means it can't compress into jumbo buffers associated with gigabit ethernet and the like. We were thinking it might be a good idea to have a flag associated with mbufs which means they are writable, providing the reference count is 1. Then we can provide a macro for checking writability. This flag could be set on jumbo ethernet buffers, but not sendfile buffers (for example). David. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message