From: Peter Zijlstra <peterz@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Gioh Kim <gioh.kim@lge.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
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, linux-mm@kvack.org,
Minchan Kim <minchan@kernel.org>, Joonsoo Kim <js1304@gmail.com>
Subject: Re: [PATCH 0/2] new API to allocate buffer-cache for superblock in non-movable area
Date: Wed, 30 Jul 2014 12:19:20 +0200 [thread overview]
Message-ID: <20140730101920.GI19379@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140730101143.GB19205@quack.suse.cz>
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On Wed, Jul 30, 2014 at 12:11:43PM +0200, Jan Kara wrote:
> > sb_bread allocates page from movable area but it is not movable until the
> > reference counter of the buffer-head becomes zero.
> > There is no lock for the buffer but the reference counter acts like lock.
> OK, but why do you care about a single page (of at most handful if you
> have more filesystems) which isn't movable? That shouldn't make a big
> difference to compaction...
The thing is, CMA _must_ be able to clear all the pages in its range,
otherwise its broken.
So placing nonmovable pages in a movable block utterly wrecks that.
Now, Ted said that there's more effectively pinned stuff from
filesystems (and I imagine those would be things like the root inode
etc.) and those would equally wreck this..
But Gioh didn't mention any of that.. he should I suppose.
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next prev parent reply other threads:[~2014-07-30 10:19 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <53CDF437.4090306@lge.com>
[not found] ` <20140722073005.GT3935@laptop>
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 [this message]
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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