From: Dave Chinner <david@fromorbit.com>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.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: buffer heads: Support slab defrag
Date: Sat, 30 Jan 2010 12:59:02 +1100 [thread overview]
Message-ID: <20100130015902.GI15853@discord.disaster> (raw)
In-Reply-To: <20100129205003.813495196@quilx.com>
On Fri, Jan 29, 2010 at 02:49:41PM -0600, Christoph Lameter wrote:
> Defragmentation support for buffer heads. We convert the references to
> buffers to struct page references and try to remove the buffers from
> those pages. If the pages are dirty then trigger writeout so that the
> buffer heads can be removed later.
NACK.
We don't want another random single page writeback trigger into
the VM - it will only slow down cleaning of dirty pages by causing
disk thrashing (i.e. turns writeback into small random write
workload), and that will ultimately slow down the rate at which we can
reclaim buffer heads.
Hence I suggest that if the buffer head is dirty, then just ignore
it - it'll be cleaned soon enough by one of the other mechanisms we
have and then it can be reclaimed in a later pass.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2010-01-30 1:59 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 [this message]
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
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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