Date: Tue, 2 Mar 2010 19:52:40 -0500 (EST) From: Rick Macklem <rmacklem@uoguelph.ca> To: Daniel Braniss <danny@cs.huji.ac.il> Cc: stable@freebsd.org, freebsd-fs@freebsd.org, Willem Jan Withagen <wjw@digiware.nl>, =?utf-8?B?R2Vycml0IEvDvGhu?= <gerrit@pmp.uni-hannover.de>, =?utf-8?B?RWlyaWsgw5h2ZXJieQ==?= <ltning@anduin.net>, rwatson@freebsd.org, Jeremy Chadwick <freebsd@jdc.parodius.com> Subject: Re: mbuf leakage with nfs/zfs? Message-ID: <Pine.GSO.4.63.1003021947470.3879@muncher.cs.uoguelph.ca> In-Reply-To: <E1NmPHy-0009jy-Dj@kabab.cs.huji.ac.il> References: <20100226174021.8feadad9.gerrit@pmp.uni-hannover.de> <E1Nl6VA-000557-D9@kabab.cs.huji.ac.il> <20100226224320.8c4259bf.gerrit@pmp.uni-hannover.de> <4B884757.9040001@digiware.nl> <20100227080220.ac6a2e4d.gerrit@pmp.uni-hannover.de> <4B892918.4080701@digiware.nl> <20100227202105.f31cbef7.gerrit@pmp.uni-hannover.de> <20100227193819.GA60576@icarus.home.lan> <BD8AC9F6-DF96-41F9-8E92-48A4E5606DC7@anduin.net> <4B89943C.70704@digiware.nl> <20100227220310.GA65110@icarus.home.lan> <Pine.GSO.4.63.1003011703100.26054@muncher.cs.uoguelph.ca> <E1NmPHy-0009jy-Dj@kabab.cs.huji.ac.il>
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On Tue, 2 Mar 2010, Daniel Braniss wrote: > runing with the experimental nfs server all is ok! > (at least I can't see any mbuf leakage :-) > > so now that we can assume that the problem is in NFS/UDP writes via > classic nfsserver, where to look? > It might also be the krpc reply cache, since the experimental server isn't using it (nfsv4 requires a rather twisted reply cache and it was easier to just use that one for nfsv2,3 for the experimental server, as well). >> If it doesn't go away, the problem is more likely in the krpc or the >> generic udp code. (When I looked at svc_dg.c, I could only spot one >> possible leak and you've already determined that patch doesn't help. >> The other big difference when using udp on the FreeBSD8 krpc is the >> reply cache code. I seem to recall it's an lru cache with a fixed upper >> bound, but it might be broken and leaking. >> >> If you change the server to set sp_rcache = NULL in the initialization >> function in sys/nfsserver/nfs_srvkrpc.c, I think that disables the replay >> cache. You wouldn't want to run this way in production, but it would >> determine if the leak is in it. >> >> Change the 3 lines in nfsrv_init() to: >> nfsrv_pool->sp_rcache = NULL; >> nfsrv_pool->sp_assign = NULL; >> nfsrv_pool->sp_done = NULL; >> >> and I think the krpc replay cache will be disabled. >> If someone gets a chance to try the above (not in production mode:-), it will determine if the problem is in the reply cache or the nfs server's write code. >> Good luck with it and please report back if you get to try the above. >> Thanks for trying the experimental server. It is getting narrowed down, due to everyone's work on it. rick
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