Date: Mon, 25 Jul 2011 19:01:32 +0200 From: Clinton Adams <clinton.adams@gmail.com> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: FreeBSD FS <freebsd-fs@freebsd.org> Subject: Re: nfsd server cache flooded, try to increase nfsrc_floodlevel Message-ID: <CAEuopLZV7NBRkp-Fbs_Tim2_DzqtqwJZWp-4iR4UReFdwjQgAw@mail.gmail.com> In-Reply-To: <1730895125.912894.1311373009726.JavaMail.root@erie.cs.uoguelph.ca> References: <CAEuopLZMEvm56s3N5MgN%2B7mGCdoP_RkZa3R2zd5QG1dbLtVqaA@mail.gmail.com> <1730895125.912894.1311373009726.JavaMail.root@erie.cs.uoguelph.ca>
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On Sat, Jul 23, 2011 at 12:16 AM, Rick Macklem <rmacklem@uoguelph.ca> wrote= : > Clinton Adams wrote: > [stuff snipped for brevity] >> >> Running four clients now and the LockOwners are steadily climbing, >> nfsstat consistently reported it as 0 prior to users logging into the >> nfsv4 test systems - my testing via ssh didn't show anything like >> this. Attached tcpdump file is from when I first noticed the jump in >> LockOwners from 0 to ~600. I tried wireshark on this and didn't see >> any releaselockowner operations. >> > [stuff snipped for brevity] >> OpenOwner Opens LockOwner Locks Delegs >> 6 242 2481 22 0 >> Server Cache Stats: >> Inprog Idem Non-idem Misses CacheSize TCPPeak >> 0 0 2 2518251 2502 4772 >> > I've written a small test program: > =A0http://people.freebsd.org/~rmacklem/childlock.c (also attached) > > where a parent process opens a file and then forks children that do > lock ops and then exit. (I'm guessing that this is what some process > in your clients are doing, that result in the LockOwner count growing.) > > When I run this program on Fedora15, it generates ReleaseLockOwner Ops > and the LockOwner count doesn't increase as it runs. > > You can run this program by giving it an argument that can be any file > on the nfsv4 mount for which you have read/write access, then watch > the server via "nfsstat -e -s" to see if the LockOwner count increases. > > If the LockOwner count does increase, then it appears that a newer Linux > kernel will avoid the problem. Yes, a client running a newer kernel (2.6.38) does generate the release_lockowner ops. Thanks for all the help! > > If you are interested in what the packet trace looks like when running th= e > program on Fedora15, it's at: > =A0http://people.freebsd.org/~rmacklem/childlock.pcap > > rick > ps: The FreeBSD NFSv4 client doesn't currently generate the ReleaseLockOw= ner > =A0 =A0Ops for this case either. I need to come up with a patch that does= that. > >
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