From: "Ted Ts'o" <tytso@mit.edu>
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: Wed, 17 Nov 2010 18:52:30 -0500 [thread overview]
Message-ID: <20101117235230.GL3290@thunk.org> (raw)
In-Reply-To: <20101117231143.GQ22876@dastard>
On Thu, Nov 18, 2010 at 10:11:43AM +1100, Dave Chinner wrote:
> I don't think ->page_mkwrite can be worked around - we need that to
> be called on the first write fault of any mmap()d page to ensure it
> is set up correctly for writeback. If we don't get write faults
> after the page is mlock()d, then we need the ->page_mkwrite() call
> during the mlock() call.
OK, so I'm not an mm hacker, so maybe I'm missing something. Could
part of this be fixed by simply sending the write faults for
mlock()'ed pages, so page_mkwrite() gets called when the page is
dirtied. Seems like a real waste to have the file system pre-allocate
all of the blocks for a mlock()'ed region. Why does mlock() have to
result in the write faults getting suppressed when the page is
actually dirtied?
- Ted
WARNING: multiple messages have this Message-ID (diff)
From: Ted Ts'o <tytso@mit.edu>
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: Wed, 17 Nov 2010 18:52:30 -0500 [thread overview]
Message-ID: <20101117235230.GL3290@thunk.org> (raw)
In-Reply-To: <20101117231143.GQ22876@dastard>
On Thu, Nov 18, 2010 at 10:11:43AM +1100, Dave Chinner wrote:
> I don't think ->page_mkwrite can be worked around - we need that to
> be called on the first write fault of any mmap()d page to ensure it
> is set up correctly for writeback. If we don't get write faults
> after the page is mlock()d, then we need the ->page_mkwrite() call
> during the mlock() call.
OK, so I'm not an mm hacker, so maybe I'm missing something. Could
part of this be fixed by simply sending the write faults for
mlock()'ed pages, so page_mkwrite() gets called when the page is
dirtied. Seems like a real waste to have the file system pre-allocate
all of the blocks for a mlock()'ed region. Why does mlock() have to
result in the write faults getting suppressed when the page is
actually dirtied?
- Ted
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next prev parent reply other threads:[~2010-11-17 23:52 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 [this message]
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
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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