From owner-freebsd-arch Fri Dec 1 18: 1:25 2000 Delivered-To: freebsd-arch@freebsd.org Received: from feral.com (feral.com [192.67.166.1]) by hub.freebsd.org (Postfix) with ESMTP id 0C2B737B400; Fri, 1 Dec 2000 18:01:24 -0800 (PST) Received: from beppo (beppo [192.67.166.79]) by feral.com (8.9.3/8.9.3) with ESMTP id SAA08647; Fri, 1 Dec 2000 18:01:03 -0800 Date: Fri, 1 Dec 2000 18:01:04 -0800 (PST) From: Matthew Jacob Reply-To: mjacob@feral.com To: Andrew Gallatin Cc: dg@root.com, Bosko Milekic , "Kenneth D. Merry" , arch@FreeBSD.ORG, alfred@FreeBSD.ORG Subject: Re: zero copy code review In-Reply-To: <14888.22179.833528.247128@grasshopper.cs.duke.edu> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-arch@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > David Greenman writes: > > Oops. The original assumption (and code that I wrote) was that M_WAIT > > _cannot_ return a NULL pointer. This was changed in FreeBSD recently, and > > Yes, that's always been my assumption too. That's why I never noticed > it... IIRC, this has never been guaranteed. It's often unlikely that a request can't be satisfied after a sleep with the current code. We used to kill off shell pipes by spraying Sparc-1s as a test. This was another reason (at the time) that SunOS (4.2based with 4.3 changes- pipes were implemented with mbufs) was considered eligible to be replaced with SVr4. -matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message