From: Andreas Dilger <adilger@sun.com>
Subject: Re: Cleancache [PATCH 6/7] (was Transcendent Memory): ext4 hook
Date: Wed, 28 Apr 2010 17:08:54 -0600
Message-ID: <8EEE8A6D-343A-4514-BFC8-1EFEDE180B70@sun.com>
References: <20100422132929.GA27380@ca-server1.us.oracle.com>
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Cc: Chris Mason <chris.mason@oracle.com>, Al Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Theodore Ts'o" <tytso@mit.edu>, mfasheh@suse.com,
        Joel Becker <joel.becker@oracle.com>, Matthew Wilcox <matthew@wil.cx>,
        linux-btrfs@vger.kernel.org,
        "linux-kernel@vger.kernel.org Mailinglist" <linux-kernel@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org,
        linux-ext4 development <linux-ext4@vger.kernel.org>,
        ocfs2-devel@oss.oracle.com, linux-mm@kvack.org, ngupta@vflare.org,
        Jeremy Fitzhardinge <jeremy@goop.org>, JBeulich@novell.com,
        kurt.hackel@oracle.com, Nick Piggin <npiggin@suse.de>,
        dave.mccracken@oracle.com, Rik van Riel <riel@redhat.com>
To: Dan Magenheimer <dan.magenheimer@oracle.com>
Return-path: <owner-linux-mm@kvack.org>
In-Reply-To: <20100422132929.GA27380@ca-server1.us.oracle.com>
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List-Id: linux-ext4.vger.kernel.org

On 2010-04-22, at 07:29, Dan Magenheimer wrote:
> Cleancache [PATCH 6/7] (was Transcendent Memory): ext4 hook
>=20
> Filesystems must explicitly enable cleancache.  For ext4,
> all other cleancache hooks are in the VFS layer.
>=20
> Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>

Given the minimal changes being done to ext3/ext4, I don't have any =
objection to this.  Being able to hook ext4 into SSDs for hierarchical =
caching is something that will become increasingly important for huge =
ext4 filesystems.

Acked-by: Andreas Dilger <adilger@sun.com>

> Diffstat:
> super.c                                  |    2 ++
> 1 file changed, 2 insertions(+)
>=20
> --- linux-2.6.34-rc5/fs/ext4/super.c	2010-04-19 17:29:56.000000000 =
-0600
> +++ linux-2.6.34-rc5-cleancache/fs/ext4/super.c	2010-04-21 =
10:13:00.000000000 -0600
> @@ -39,6 +39,7 @@
>  #include <linux/ctype.h>
>  #include <linux/log2.h>
>  #include <linux/crc16.h>
> +#include <linux/cleancache.h>
>  #include <asm/uaccess.h>
> =20
>  #include "ext4.h"
> @@ -1784,6 +1785,7 @@ static int ext4_setup_super(struct super
>  			EXT4_INODES_PER_GROUP(sb),
>  			sbi->s_mount_opt);
>=20
> +	sb->cleancache_poolid =3D cleancache_init_fs(PAGE_SIZE);
>  	return res;
>  }


Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.

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