From owner-freebsd-hackers Thu Apr 4 21: 4:43 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from rwcrmhc54.attbi.com (rwcrmhc54.attbi.com [216.148.227.87]) by hub.freebsd.org (Postfix) with ESMTP id E39F337B41F for ; Thu, 4 Apr 2002 21:04:10 -0800 (PST) Received: from bmah.dyndns.org ([12.233.149.189]) by rwcrmhc54.attbi.com (InterMail vM.4.01.03.27 201-229-121-127-20010626) with ESMTP id <20020405050410.SFV15826.rwcrmhc54.attbi.com@bmah.dyndns.org>; Fri, 5 Apr 2002 05:04:10 +0000 Received: from intruder.bmah.org (localhost [IPv6:::1]) by bmah.dyndns.org (8.12.2/8.12.2) with ESMTP id g3554At2001201; Thu, 4 Apr 2002 21:04:10 -0800 (PST) (envelope-from bmah@intruder.bmah.org) Received: (from bmah@localhost) by intruder.bmah.org (8.12.2/8.12.2/Submit) id g355493C001200; Thu, 4 Apr 2002 21:04:09 -0800 (PST) Message-Id: <200204050504.g355493C001200@intruder.bmah.org> X-Mailer: exmh version 2.5+ 20020403 with nmh-1.0.4 To: Andrew Gallatin Cc: Will Froning , hackers@FreeBSD.ORG Subject: Re: Fatal trap 12: page fault while in kernel mode In-reply-to: <15532.29114.310072.957330@grasshopper.cs.duke.edu> References: <20020403181854.I42720-100000@angui.sh> <15532.29114.310072.957330@grasshopper.cs.duke.edu> Comments: In-reply-to Andrew Gallatin message dated "Thu, 04 Apr 2002 10:31:06 -0500." From: "Bruce A. Mah" Reply-To: bmah@FreeBSD.ORG X-Face: g~c`.{#4q0"(V*b#g[i~rXgm*w;:nMfz%_RZLma)UgGN&=j`5vXoU^@n5v4:OO)c["!w)nD/!!~e4Sj7LiT'6*wZ83454H""lb{CC%T37O!!'S$S&D}sem7I[A 2V%N&+ X-Image-Url: http://www.employees.org/~bmah/Images/bmah-cisco-small.gif X-Url: http://www.employees.org/~bmah/ Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 04 Apr 2002 21:04:09 -0800 Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG If memory serves me right, Andrew Gallatin wrote: > > Will Froning writes: > > I have a 4.5-RELEASE-p2 box that is my Firewall/NAT/NFS server. As a > > NFS client I have a RH7.2 linux box. When I do massive NFS writes to > > my FBSD (from RH7.2 box), I get a panic. I've attached the info I got > > from my debug kernel. > > > > While the fix being discussed by Peter & others will prevent panics, > the linux box will still run your server out of mbufs clusters. This > is happening because the linux box is using a 16K write size over UDP > by default. This is a stupid default. If there is any lossage > between the hosts (eg, any packets get dropped), more and more packets > will end up on the reassembly queues. Eventually, all your cluster > mbufs will be there. I was discussing this with some of my cow-orkers, as we've had a similar situation (cluster mbufs getting temporarily depleted on a 4.5-RELEASE-p2 NFS server with Linux and FreeBSD clients, but no kernel panics). Shouldn't the net.inet.ip.maxfragpackets sysctl variable (introduced in 4.4-RELEASE) limit the number of fragments on the reassembly queue(s)? This value looks to be about 1/4 the number of cluster mbufs, by default. Bruce. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message