From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Michel Lespinasse <walken@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Nick Piggin <npiggin@kernel.dk>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Theodore Tso <tytso@google.com>,
Michael Rubin <mrubin@google.com>,
Suleiman Souhlal <suleiman@google.com>
Subject: Re: [PATCH 3/3] mlock: avoid dirtying pages and triggering writeback
Date: Thu, 18 Nov 2010 08:37:02 -0500 [thread overview]
Message-ID: <20101118133702.GA18834@infradead.org> (raw)
In-Reply-To: <20101117231143.GQ22876@dastard>
On Thu, Nov 18, 2010 at 10:11:43AM +1100, Dave Chinner wrote:
> Hence I think that avoiding ->page_mkwrite callouts is likely to
> break some filesystems in subtle, undetected ways. IMO, regardless
> of what is done, it would be really good to start by writing a new
> regression test to exercise and encode the expected the mlock
> behaviour so we can detect regressions later on....
I think it would help if we could drink a bit of the test driven design
coolaid here. Michel, can you write some testcases where pages on a
shared mapping are mlocked, then dirtied and then munlocked, and then
written out using msync/fsync. Anything that fails this test on
btrfs/ext4/gfs/xfs/etc obviously doesn't work.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Michel Lespinasse <walken@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Nick Piggin <npiggin@kernel.dk>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>, Rik van Riel <riel@redhat.com>,
Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Theodore Tso <tytso@google.com>,
Michael Rubin <mrubin@google.com>,
Suleiman Souhlal <suleiman@google.com>
Subject: Re: [PATCH 3/3] mlock: avoid dirtying pages and triggering writeback
Date: Thu, 18 Nov 2010 08:37:02 -0500 [thread overview]
Message-ID: <20101118133702.GA18834@infradead.org> (raw)
In-Reply-To: <20101117231143.GQ22876@dastard>
On Thu, Nov 18, 2010 at 10:11:43AM +1100, Dave Chinner wrote:
> Hence I think that avoiding ->page_mkwrite callouts is likely to
> break some filesystems in subtle, undetected ways. IMO, regardless
> of what is done, it would be really good to start by writing a new
> regression test to exercise and encode the expected the mlock
> behaviour so we can detect regressions later on....
I think it would help if we could drink a bit of the test driven design
coolaid here. Michel, can you write some testcases where pages on a
shared mapping are mlocked, then dirtied and then munlocked, and then
written out using msync/fsync. Anything that fails this test on
btrfs/ext4/gfs/xfs/etc obviously doesn't work.
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next prev parent reply other threads:[~2010-11-18 13:37 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-17 12:23 [PATCH 0/3] Avoid dirtying pages during mlock Michel Lespinasse
2010-11-17 12:23 ` Michel Lespinasse
2010-11-17 12:23 ` [PATCH 1/3] do_wp_page: remove the 'reuse' flag Michel Lespinasse
2010-11-17 12:23 ` Michel Lespinasse
2010-11-17 12:23 ` [PATCH 2/3] do_wp_page: clarify dirty_page handling Michel Lespinasse
2010-11-17 12:23 ` Michel Lespinasse
2010-11-17 12:23 ` [PATCH 3/3] mlock: avoid dirtying pages and triggering writeback Michel Lespinasse
2010-11-17 12:23 ` Michel Lespinasse
2010-11-17 12:57 ` Nick Piggin
2010-11-17 12:57 ` Nick Piggin
2010-11-17 15:28 ` Peter Zijlstra
2010-11-17 15:28 ` Peter Zijlstra
2010-11-17 22:05 ` Michel Lespinasse
2010-11-17 22:05 ` Michel Lespinasse
2010-11-17 22:18 ` Peter Zijlstra
2010-11-17 22:18 ` Peter Zijlstra
2010-11-17 23:11 ` Dave Chinner
2010-11-17 23:11 ` Dave Chinner
2010-11-17 23:31 ` Michel Lespinasse
2010-11-17 23:31 ` Michel Lespinasse
2010-11-19 1:46 ` Dave Chinner
2010-11-19 1:46 ` Dave Chinner
2010-11-17 23:52 ` Ted Ts'o
2010-11-17 23:52 ` Ted Ts'o
2010-11-18 0:53 ` Andrew Morton
2010-11-18 0:53 ` Andrew Morton
2010-11-18 11:03 ` Michel Lespinasse
2010-11-18 11:03 ` Michel Lespinasse
2010-11-18 13:37 ` Christoph Hellwig [this message]
2010-11-18 13:37 ` Christoph Hellwig
2010-11-18 17:41 ` Hugh Dickins
2010-11-18 17:41 ` Hugh Dickins
2010-11-19 7:23 ` Michel Lespinasse
2010-11-19 7:23 ` Michel Lespinasse
2010-11-19 13:38 ` Theodore Tso
2010-11-19 13:42 ` Theodore Tso
2010-11-19 13:42 ` Theodore Tso
2010-11-19 15:06 ` Christoph Hellwig
2010-11-19 15:06 ` Christoph Hellwig
2010-11-19 22:54 ` Andrew Morton
2010-11-19 22:54 ` Andrew Morton
2010-11-19 23:22 ` Ted Ts'o
2010-11-19 23:22 ` Ted Ts'o
2010-11-20 0:29 ` Dustin Kirkland
2010-11-19 23:31 ` Michel Lespinasse
2010-11-19 23:31 ` Michel Lespinasse
2010-11-19 23:54 ` Dave Chinner
2010-11-19 23:54 ` Dave Chinner
2010-11-18 5:46 ` Nick Piggin
2010-11-18 5:46 ` Nick Piggin
2010-11-18 10:43 ` Theodore Tso
2010-11-18 10:43 ` Theodore Tso
2010-11-18 13:39 ` Christoph Hellwig
2010-11-18 13:39 ` Christoph Hellwig
2010-11-18 18:00 ` Hugh Dickins
2010-11-18 18:00 ` Hugh Dickins
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