Date: Wed, 10 Jan 2007 19:15:34 -0500 From: "Brad L. Chisholm" <blc@bsdwins.com> To: John Baldwin <jhb@freebsd.org> Cc: "Brad L. Chisholm" <blc@bsdwins.com>, freebsd-hackers@freebsd.org Subject: Re: Kernel hang on 6.x Message-ID: <20070111001534.GA319@bsdone.bsdwins.com> In-Reply-To: <200701101753.24716.jhb@freebsd.org> References: <20070110215207.GA85834@bsdone.bsdwins.com> <200701101753.24716.jhb@freebsd.org>
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On Wed, Jan 10, 2007 at 05:53:24PM -0500, John Baldwin wrote: > On Wednesday 10 January 2007 16:52, Brad L. Chisholm wrote: > > > > I work with Brian, and have been helping him analyze this problem. We have > > been able to generate kernel dumps, and have also done some additional > > analysis under ddb. Here is a summary of our analysis so far. Suggestions > > as to how to proceed from here are most welcome. > > How much swap do you have? You might have run out of buckets in the > swap_zone before you ran out of swap space, in which case the kernel > deadlocks rather than killing the hog like it does when it runs out of > swap space. I added a printf to catch this on HEAD recently that will > be MFC'd soonish. You can try bumping up kern.maxswzone (loader tunable). > It has a 32GB swap partition. We have also run it configured with an additional 32GB swap file, for a total of 64GB. Changing the amount of swap did not seem to affect the hang. However, as I mentioned in my previous post, the hang appears to always occur when ~14GB of swap have been consumed, regardless of the amount of swap or physmen configured. This does make it sound like a limit (such as swap_zone buckets) has been reached. I notice the following in the vm.zone output captured just prior to a hang. Does this value correspond to the swap_zone you were referring to? This looks like a limit may have been reached. SWAPMETA: 288, 116519, 116519, 0, 116543 I don't seem to be able to query kern.maxswzone on our 6.2-BETA2 image: # sysctl kern.maxswzone sysctl: unknown oid 'kern.maxswzone' Is it available in 6.x, or is it something newer? Thanks! --- Brad Chisholm blc@bsdwins.com
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