Date: Mon, 10 Jan 2005 21:08:01 -0500
From: Mike Waychison <Michael.Waychison@Sun.COM>
Subject: Re: [patch] Per-sb s_all_inodes list
In-reply-to: <20050111012311.GD2696@holomorphy.com>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: Linux kernel <linux-kernel@vger.kernel.org>,
       viro@parcelfarce.linux.theplanet.co.uk
Message-id: <41E33501.1050506@sun.com>
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William Lee Irwin III wrote:
> On Mon, Jan 10, 2005 at 04:19:24PM -0500, Mike Waychison wrote:
> 
>>Releasing a super_block requires walking all inodes for the given
>>superblock and releasing them. Currently, inodes are found on one of
>>four lists:
> 
> [...]
> 
>>The second list, inode_unused can potentially be quite large.
>>Unfortunately, it cannot be made per-sb as it is the global LRU list
>>used for inode cache reduction under memory pressure.
>>When unmounting a single filesystem, profiling shows dramatic time spent
>>walking inode_unused.  This because very noticeble when one is
>>unmounting a decently sized tree of filesystems.
>>The proposed solution is to create a new list per-sb, that contains all
>>inodes allocated.  It is maintained under the inode_lock for the sake of
>>simplicity, but this may prove unneccesary, and may be better done with
>>another global or per-sb lock.
> 
> 
> I thought this was a good idea a number of months ago myself when I saw
> a patch for 2.4.x implementing this from Kirill Korotaev, so I ported
> that code to 2.6.x and it got merged in -mm then. That patch was merged
> into Linus' bk shortly after 2.6.10. Could you check Linus' bk to see
> if what made it there resolves the issue as well as your own?
> 

Excellent.  I eyeballed the patch on bkbits.net and it does exactly what
I posted.

Thanks,

- --
Mike Waychison
Sun Microsystems, Inc.
1 (650) 352-5299 voice
1 (416) 202-8336 voice

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NOTICE:  The opinions expressed in this email are held by me,
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