Date: Fri, 11 Mar 2011 16:35:19 -0500
From: "J. Bruce Fields" <bfields@fieldses.org>
To: Simon Kirby <sim@hostway.ca>
Cc: Mark Moseley <moseleymark@gmail.com>, linux-nfs@vger.kernel.org,
        Al Viro <viro@ZenIV.linux.org.uk>, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org
Subject: Re: [git pull] more vfs fixes for final
Message-ID: <20110311213519.GA9404@fieldses.org>
References: <20110310110931.GF22723@ZenIV.linux.org.uk>
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 <20110310115856.GG22723@ZenIV.linux.org.uk>
 <20110311210938.GB8211@hostway.ca>
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On Fri, Mar 11, 2011 at 01:09:38PM -0800, Simon Kirby wrote:
> On Thu, Mar 10, 2011 at 11:58:56AM +0000, Al Viro wrote:
> 
> > commit d891eedbc3b1b0fade8a9ce60cc0eba1cccb59e5
> > Author: J. Bruce Fields <bfields@fieldses.org>
> > Date:   Tue Jan 18 15:45:09 2011 -0500
> > 
> >     fs/dcache: allow d_obtain_alias() to return unhashed dentries
> 
> Hmm, I was hoping this or something recently would fix nfs_inode_cache
> growing forever and flush processes taking lots of system time since
> 2.6.36. For example:
> 
>   OBJS ACTIVE  USE OBJ SIZE  SLABS OBJ/SLAB CACHE SIZE NAME
> 3457486 3454365  99%    0.95K 105601       33   3379232K nfs_inode_cache
> 469638 248761  52%    0.10K  12042       39     48168K buffer_head
> 243712 216348  88%    0.02K    952      256      3808K kmalloc-16
> 232785 202185  86%    0.19K  11085       21     44340K dentry
> 149696  54633  36%    0.06K   2339       64      9356K kmalloc-64
> 115976 106806  92%    0.55K   4142       28     66272K radix_tree_node
>  76064  45680  60%    0.12K   2377       32      9508K kmalloc-128
>  62336  53427  85%    0.03K    487      128      1948K kmalloc-32
>  41958  41250  98%    0.75K   1998       21     31968K ext3_inode_cache
> 
> This clears them all, similar to what you posted:
> 
> echo 2 > /proc/sys/vm/drop_caches
> sync
> echo 2 > /proc/sys/vm/drop_caches
> 
> ...but 2.6.38-rc8 still doesn't seem to fix it.
> 
> http://0x.ca/sim/ref/2.6.37/cpu3_nfs.png
> http://www.spinics.net/lists/linux-nfs/msg18212.html
> 
> Any ideas?  This started with 2.6.36.

Do you have NFSv4 clients that are doing locking?  Then it's probably
0997b17360 and 529d7b2a7f on the for-2.6.39 branch at:

	git://linux-nfs.org/~bfields/linux.git for-2.6.39

Let me know if not.

Those should go into 2.6.39 and stable when the merge window opens.  I
would have tried to slip them into 2.6.38 but they just didn't seem
quite trivial enough given where we are in the release process.

--b.