Date: Tue, 12 Oct 2010 14:12:28 +0300 From: Andriy Gapon <avg@icyb.net.ua> To: Jeremy Chadwick <freebsd@jdc.parodius.com> Cc: freebsd-fs@freebsd.org Subject: Re: Locked up processes after upgrade to ZFS v15 Message-ID: <4CB4429C.9040109@icyb.net.ua> In-Reply-To: <20101012100709.GA29861@icarus.home.lan> References: <39F05641-4E46-4BE0-81CA-4DEB175A5FBE@free.de> <20101009111241.GA58948@icarus.home.lan> <CF901B53-657E-49FC-A43B-27BC7D49F7A7@free.de> <4CB17983.3020907@icyb.net.ua> <20101011151508.GA10917@icarus.home.lan> <4CB32C75.2060000@icyb.net.ua> <20101011183707.GA13925@icarus.home.lan> <4CB3870F.7070107@icyb.net.ua> <20101012100709.GA29861@icarus.home.lan>
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on 12/10/2010 13:07 Jeremy Chadwick said the following: > I've been trying to reproduce this problem on my testbed box without > much luck so far. The box differs severely -- the biggest differences > being the testbed runs i386 (due to CPU), only has 1GB RAM, and is > single-core. I don't have an amd64 testbed system on hand right now. > > I've been trying to reproduce it by enabling Sendfile and MMAP in Apache > on the system, putting up some very large files on an Apache-accessible > ZFS filesystem, and using something like "wget -r" to download > everything. I've been watching "netstat -m" to monitor the number of > sendfile requests. > > There have been a couple cases where I've seen processes go into "zfs" > state, but I have yet to see any lock up. > > Is there something amd64-specific to the problem at hand, or maybe some > VM feature which isn't getting triggered on i386? Or do you know of a > reliable way to reproduce the issue at this point? I don't have an easy way to reproduce it. The theory is that you should sendfile a file with size which is not multiple of page size (4K) and then you should mmap and read the same file; the last step should lock up. Perhaps, tools/regression/sockets/sendfile/sendfile.c with the following patch would reproduce it? http://people.freebsd.org/~avg/sendfile.diff -- Andriy Gapon
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