Date: Thu, 4 Apr 2002 10:31:06 -0500 (EST) From: Andrew Gallatin <gallatin@cs.duke.edu> To: Will Froning <wfroning@angui.sh> Cc: hackers@freebsd.org Subject: Re: Fatal trap 12: page fault while in kernel mode Message-ID: <15532.29114.310072.957330@grasshopper.cs.duke.edu> In-Reply-To: <20020403181854.I42720-100000@angui.sh> References: <20020403181854.I42720-100000@angui.sh>
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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 suggest changing the mount options on the linux box to use 8k reads and writes, or use TCP. Another problem I've see w/Linux NFS clients is that recent linux NFS clients seem to spew ACCESS requests like there's no tomorrow & beats the snot out of my NFS server. When building large software pacakges via "make -j4" over NFSv3 (100Mb ethernet) on a dual PIII 1GHz system, a FreeBSD 4.5 host issues 400-500 ACCESS calls/sec. A Linux 2.4.18 host spews 12,000 - 14,000 ACCESS calls/sec, or roughly 30 times as many. Needless to say, the build finishes a whole lot quicker on FreeBSD. Does anybody know what I can do to make the linux client cache ACCESS info? Cheers, Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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