From owner-freebsd-stable Wed Mar 6 15:21:23 2002 Delivered-To: freebsd-stable@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id 661E237B404 for ; Wed, 6 Mar 2002 15:21:18 -0800 (PST) Received: (from dillon@localhost) by apollo.backplane.com (8.11.6/8.9.1) id g26NLE959185; Wed, 6 Mar 2002 15:21:14 -0800 (PST) (envelope-from dillon) Date: Wed, 6 Mar 2002 15:21:14 -0800 (PST) From: Matthew Dillon Message-Id: <200203062321.g26NLE959185@apollo.backplane.com> To: Ian Dowse Cc: "Jan L. Peterson" , freebsd-stable@FreeBSD.ORG Subject: Re: crashes on 4.5-RELEASE References: <200203062302.aa66019@salmon.maths.tcd.ie> Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG :... :> in a heavily loaded environment would be enough to cause the output :> buffer to grow to a considerable size. : :Yes, that's certainly possible. Can someone who has a crash dump :handy run : : netstat -m -N kernel.X -M vmcore.X : :to get the mbuf stats? I think with TCP the buildup would be much :slower, as a (as far as I remember) retransmits are limited. In :-CURRENT (which is the only place I have seen the IPFW/NFS mbuf :exhaustion) I think sosend() was returning EPERM, but the mbufs :were still building up. That may be a new bug somewhere. : :Ian If I remember right there are no retransmits with a TCP mount, but if you have a lot of client processes banging out NFS requests and one direction of the TCP link stalls you can get a build up. This would be further irritated by nfsiod doing look-aheads. I do not know if the build-up itself is even responsible... it could very well be the *rate* of the build-up... i.e. a sudden burst of a hundred kilobytes all at once might not exhaust the mbuf pool, but it could certainly exhaust our free page reserve and prevent an interrupt from being able to allocate an mbuf temporarily. -Matt Matthew Dillon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message