Date: Fri, 21 Dec 2007 15:43:47 -0800 From: David G Lawrence <dg@dglawrence.com> To: Alfred Perlstein <alfred@freebsd.org> Cc: freebsd-net@freebsd.org, freebsd-stable@freebsd.org Subject: Re: Packet loss every 30.999 seconds Message-ID: <20071221234347.GS25053@tnn.dglawrence.com> In-Reply-To: <20071221200810.GY16982@elvis.mu.org> References: <D50B5BA8-5A80-4370-8F20-6B3A531C2E9B@eng.oar.net> <20071217102433.GQ25053@tnn.dglawrence.com> <CD187AD1-8712-418F-9F49-FA3407BA1AC7@eng.oar.net> <20071220011626.U928@besplex.bde.org> <814DB7A9-E64F-4BCA-A502-AB5A6E0297D3@eng.oar.net> <20071219171331.GH25053@tnn.dglawrence.com> <20071221200810.GY16982@elvis.mu.org>
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> > Unfortunately, the version of the patch that I sent out isn't going to > > help your problem. It needs to yield at the top of the loop, but vp isn't > > necessarily valid after the wakeup from the msleep. That's a problem that > > I'm having trouble figuring out a solution to - the solutions that come > > to mind will all significantly increase the overhead of the loop. > > I apologize for not reading the code as I am swamped, but a technique > that Matt Dillon used for bufs might work here. > > Can you use a placeholder vnode as a place to restart the scan? > you might have to mark it special so that other threads/things > (getnewvnode()?) don't molest it, but it can provide for a convenient > restart point. That was one of the solutions that I considered and rejected since it would significantly increase the overhead of the loop. The solution provided by Kostik Belousov that uses uio_yield looks like a find solution. I intend to try it out on some servers RSN. -DG David G. Lawrence President Download Technologies, Inc. - http://www.downloadtech.com - (866) 399 8500 The FreeBSD Project - http://www.freebsd.org Pave the road of life with opportunities.
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