From: Andi Kleen <andi@firstfloor.org>
To: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
Christoph Lameter <cl@linux-foundation.org>,
Andi Kleen <andi@firstfloor.org>,
Dave Chinner <david@fromorbit.com>,
Alexander Viro <viro@ftp.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>,
Christoph Lameter <clameter@sgi.com>,
Rik van Riel <riel@redhat.com>,
Pekka Enberg <penberg@cs.helsinki.fi>,
akpm@linux-foundation.org, Miklos Szeredi <miklos@szeredi.hu>,
Nick Piggin <nickpiggin@yahoo.com.au>,
Hugh Dickins <hugh@veritas.com>,
linux-kernel@vger.kernel.org
Subject: Re: dentries: dentry defragmentation
Date: Mon, 1 Feb 2010 11:10:13 +0100 [thread overview]
Message-ID: <20100201101013.GG29555@one.firstfloor.org> (raw)
In-Reply-To: <20100201070835.GE9085@laptop>
On Mon, Feb 01, 2010 at 06:08:35PM +1100, Nick Piggin wrote:
> I always preferred to do defrag in the opposite way. Ie. query the
> slab allocator from existing shrinkers rather than opposite way
> around. This lets you reuse more of the locking and refcounting etc.
I looked at this for hwpoison soft offline.
But it works really badly because the LRU list ordering
has nothing to do with the actual ordering inside the slab pages.
Christoph's basic approach is more efficient.
> So you have a pin on the object somehow via the normal shrinker path,
> and therefore you get a pin on the underlying slab. I would just like
> to see even performance of a real simple approach that just asks
> whether we are in this slab defrag mode, and if so, whether the slab
> is very sparse. If yes, then reclaim aggressively.
The typical result is that you need to get through most of the LRU
list (and prune them all) just to free the page.
>
> If that doesn't perform well enough and you have to go further and
It doesn't.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2010-02-01 10:10 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-29 20:49 Slab Fragmentation Reduction V15 Christoph Lameter
2010-01-29 20:49 ` slub: Add defrag_ratio field and sysfs support Christoph Lameter
2010-01-29 20:49 ` slub: Replace ctor field with ops field in /sys/slab/* Christoph Lameter
2010-01-29 20:49 ` slub: Add get() and kick() methods Christoph Lameter
2010-01-29 20:49 ` slub: Sort slab cache list and establish maximum objects for defrag slabs Christoph Lameter
2010-01-29 20:49 ` slub: Slab defrag core Christoph Lameter
2010-01-29 20:49 ` slub: Add KICKABLE to avoid repeated kick() attempts Christoph Lameter
2010-01-29 20:49 ` slub: Extend slabinfo to support -D and -F options Christoph Lameter
2010-01-29 20:49 ` slub/slabinfo: add defrag statistics Christoph Lameter
2010-01-29 20:49 ` slub: Trigger defragmentation from memory reclaim Christoph Lameter
2010-01-29 20:49 ` buffer heads: Support slab defrag Christoph Lameter
2010-01-30 1:59 ` Dave Chinner
2010-02-01 6:39 ` Nick Piggin
2010-01-29 20:49 ` inodes: Support generic defragmentation Christoph Lameter
2010-01-30 2:43 ` Dave Chinner
2010-02-01 17:50 ` Christoph Lameter
2010-01-30 19:26 ` tytso
2010-01-31 8:34 ` Andi Kleen
2010-01-31 13:59 ` Dave Chinner
2010-02-03 15:31 ` Christoph Lameter
2010-02-04 0:34 ` Dave Chinner
2010-02-04 3:07 ` tytso
2010-02-04 3:39 ` Dave Chinner
2010-02-04 9:33 ` Nick Piggin
2010-02-04 17:13 ` Christoph Lameter
2010-02-08 7:37 ` Nick Piggin
2010-02-08 17:40 ` Christoph Lameter
2010-02-08 22:13 ` Dave Chinner
2010-02-04 16:59 ` Christoph Lameter
2010-02-06 0:39 ` Dave Chinner
2010-01-31 21:02 ` tytso
2010-02-01 10:17 ` Andi Kleen
2010-02-01 13:47 ` tytso
2010-02-01 13:54 ` Andi Kleen
2010-01-29 20:49 ` Filesystem: Ext2 filesystem defrag Christoph Lameter
2010-01-29 20:49 ` Filesystem: Ext3 " Christoph Lameter
2010-01-29 20:49 ` Filesystem: Ext4 " Christoph Lameter
2010-01-29 20:49 ` Filesystem: XFS slab defragmentation Christoph Lameter
2010-01-29 20:49 ` Filesystems: /proc filesystem support for slab defrag Christoph Lameter
2010-01-29 20:49 ` dentries: dentry defragmentation Christoph Lameter
2010-01-29 22:00 ` Al Viro
2010-02-01 7:08 ` Nick Piggin
2010-02-01 10:10 ` Andi Kleen [this message]
2010-02-01 10:16 ` Nick Piggin
2010-02-01 10:22 ` Andi Kleen
2010-02-01 10:35 ` Nick Piggin
2010-02-01 10:45 ` Andi Kleen
2010-02-01 10:56 ` Nick Piggin
2010-02-01 13:25 ` Andi Kleen
2010-02-01 13:36 ` Nick Piggin
2010-01-29 20:49 ` slub defrag: Transition patch upstream -> -next Christoph Lameter
2010-01-30 8:54 ` Slab Fragmentation Reduction V15 Pekka Enberg
2010-01-30 10:48 ` Andi Kleen
2010-01-30 14:53 ` Rik van Riel
2010-02-01 17:53 ` Christoph Lameter
2010-02-01 17:52 ` Christoph Lameter
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