From: Peter Zijlstra <peterz@infradead.org>
To: Gioh Kim <gioh.kim@lge.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Jan Kara <jack@suse.cz>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
"Theodore Ts'o" <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
linux-ext4@vger.kernel.org
Subject: Re: [PATCH 0/2] new API to allocate buffer-cache for superblock in non-movable area
Date: Tue, 22 Jul 2014 09:30:05 +0200 [thread overview]
Message-ID: <20140722073005.GT3935@laptop> (raw)
In-Reply-To: <53CDF437.4090306@lge.com>
On Tue, Jul 22, 2014 at 02:18:47PM +0900, Gioh Kim wrote:
> Hello,
>
> This patch try to solve problem that a long-lasting page cache of
> ext4 superblock disturbs page migration.
>
> I've been testing CMA feature on my ARM-based platform
> and found some pages for page caches cannot be migrated.
> Some of them are page caches of superblock of ext4 filesystem.
>
> Current ext4 reads superblock with sb_bread(). sb_bread() allocates page
> from movable area. But the problem is that ext4 hold the page until
> it is unmounted. If root filesystem is ext4 the page cannot be migrated forever.
>
> I introduce a new API for allocating page from non-movable area.
> It is useful for ext4 and others that want to hold page cache for a long time.
There's no word on why you can't teach ext4 to still migrate that page.
For all I know it might be impossible, but at least mention why.
next prev parent reply other threads:[~2014-07-22 7:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-22 5:18 [PATCH 0/2] new API to allocate buffer-cache for superblock in non-movable area Gioh Kim
2014-07-22 7:30 ` Peter Zijlstra [this message]
2014-07-22 8:14 ` Theodore Ts'o
2014-07-27 1:01 ` Theodore Ts'o
2014-07-30 7:56 ` Gioh Kim
2014-07-22 9:38 ` Jan Kara
2014-07-30 7:44 ` Gioh Kim
2014-07-30 7:57 ` Kyungmin Park
2014-07-30 10:11 ` Jan Kara
2014-07-30 10:19 ` Peter Zijlstra
2014-07-30 23:45 ` Gioh Kim
2014-07-30 23:54 ` Gioh Kim
2014-07-31 0:03 ` Jan Kara
2014-07-31 0:37 ` Gioh Kim
2014-07-31 12:21 ` Jan Kara
2014-08-01 0:07 ` Gioh Kim
2014-08-01 1:06 ` Gioh Kim
2014-08-01 9:57 ` Jan Kara
2014-08-01 13:36 ` Peter Zijlstra
2014-08-01 15:24 ` Jan Kara
2014-08-01 16:04 ` Peter Zijlstra
2014-08-06 6:15 ` Gioh Kim
2014-08-01 8:34 ` Joonsoo Kim
2014-08-01 9:15 ` Jan Kara
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