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From: Frank van Maarseveen <frankvm@frankvm.com>
To: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Linux NFS mailing list <linux-nfs@vger.kernel.org>
Subject: Re: 3.1.4: NFSv3 RPC scheduling issue?
Date: Wed, 7 Dec 2011 14:43:59 +0100	[thread overview]
Message-ID: <20111207134359.GA29828@janus> (raw)
In-Reply-To: <1323201463.3199.18.camel@lade.trondhjem.org>

On Tue, Dec 06, 2011 at 02:57:43PM -0500, Trond Myklebust wrote:
> On Tue, 2011-12-06 at 09:11 +0100, Frank van Maarseveen wrote: 
> > On Mon, Dec 05, 2011 at 06:39:36PM -0500, Trond Myklebust wrote:
> > > On Mon, 2011-12-05 at 17:50 +0100, Frank van Maarseveen wrote: 
> > > > After upgrading 50+ NFSv3 (over UDP) client machines from 3.0.x to
> > > > 3.1.4 I occasionally noticed a machine with lots of processes hanging
> > > > in __rpc_execute() for a specific mount point with no progress at all.
> > > > Stack:
> > > > 
> > > > 	[<c17fe7e0>] schedule+0x30/0x50
> > > > 	[<c177e259>] rpc_wait_bit_killable+0x19/0x30
> > > > 	[<c17feeb5>] __wait_on_bit+0x45/0x70
> > > > 	[<c177e240>] ? rpc_release_task+0x110/0x110
> > > > 	[<c17fef3d>] out_of_line_wait_on_bit+0x5d/0x70
> > > > 	[<c177e240>] ? rpc_release_task+0x110/0x110
> > > > 	[<c108aed0>] ? autoremove_wake_function+0x40/0x40
> > > > 	[<c177e89b>] __rpc_execute+0xdb/0x1a0
> > > > 	...
> > > > 
> > > > Every reference to the specific mount point on the client machine hangs
> > > > and the server does not receive any related network traffic. The server
> > > > works fine for other identical client machines with the same export mounted.
> > > > Other mounts on the (now) broken client still work. Killing the hanging
> > > > client processes repairs the situation.
> > > > 
> > > > This has happened a couple of times on client machines with heavy (NFS)
> > > > load. The mount-point has originally been mounted by the automounter.
> > > 
> > > An command of 'echo 0 > /proc/sys/sunrpc/rpc_debug', should display a
> > 
> > 36477 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:none
> > 36479 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 LOOKUP a:call_reserveresult q:xprt_sending
> > 36484 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 LOOKUP a:call_reserveresult q:xprt_sending
> > 36485 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 LOOKUP a:call_reserveresult q:xprt_sending
> > 36486 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36487 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 LOOKUP a:call_reserveresult q:xprt_sending
> > 36488 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36489 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 LOOKUP a:call_reserveresult q:xprt_sending
> > 36490 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36491 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36492 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36493 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36494 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36495 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36496 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 GETATTR a:call_reserveresult q:xprt_sending
> > 36497 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36498 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 LOOKUP a:call_reserveresult q:xprt_sending
> > 36499 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36500 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36501 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36502 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36503 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 LOOKUP a:call_reserveresult q:xprt_sending
> > 36504 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36505 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36506 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36507 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36508 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36509 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36510 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36511 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36512 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36513 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36514 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36515 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36516 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36517 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36518 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36519 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36523 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36560 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36561 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36562 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36563 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36564 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36565 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36566 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36576 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 GETATTR a:call_reserveresult q:xprt_sending
> > 36577 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36578 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36579 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36580 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36581 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36582 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36583 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> > 36592 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 GETATTR a:call_reserveresult q:xprt_sending
> > 36618 0001    -11 ffff88008dc9db60   (null)        0 ffffffff8193ba60 nfsv3 WRITE a:call_reserveresult q:xprt_sending
> > 21609 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
> 
> Hmm... Is this the full dump from that client? I have a theory about
> what is going on with the second dump that you showed, but I really do
> not understand this one... If the above trace is complete, then it would
> indicate that the value of xprt->snd_task has been corrupted somehow.

I did three more 'echo 0 > /proc/sys/sunrpc/rpc_debug' before repairing
the mount and outputs differ slightly (file '1' contains above dump, 2,
3 and 4 are the others):

diff 1 2:
| 58d57
| < 21609 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
diff 1 3:
| 47d46
| < 36566 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
| 58c57
| < 21609 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
| ---
| > 33046 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
diff 1 4:
| 16d15
| < 36496 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 GETATTR a:call_reserveresult q:xprt_sending
| 47d45
| < 36566 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
| 58c56,57
| < 21609 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
| ---
| > 33046 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending
| > 34798 0080    -11 ffff88008dc9db60   (null)        0 ffffffff81a68860 nfsv3 ACCESS a:call_reserveresult q:xprt_sending

-- 
Frank

  reply	other threads:[~2011-12-07 13:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-05 16:50 3.1.4: NFSv3 RPC scheduling issue? Frank van Maarseveen
2011-12-05 23:39 ` Trond Myklebust
2011-12-06  8:11   ` Frank van Maarseveen
2011-12-06 19:57     ` Trond Myklebust
2011-12-07 13:43       ` Frank van Maarseveen [this message]
2011-12-10  3:10         ` Trond Myklebust
2011-12-11 12:40           ` Frank van Maarseveen
2011-12-11 18:10             ` Frank van Maarseveen
2011-12-11 14:09           ` Frank van Maarseveen
2011-12-06  9:04   ` Frank van Maarseveen

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