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From: "Eugene V. Lyubimkin" <jackyf.devel@gmail.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Chris Friesen <cfriesen@nortel.com>,
	Rik van Riel <riel@redhat.com>,
	linux-kernel@vger.kernel.org, linux-mm <linux-mm@kvack.org>,
	hugh <hugh@veritas.com>
Subject: Re: mmap: is default non-populating behavior stable?
Date: Tue, 04 Nov 2008 18:51:36 +0200	[thread overview]
Message-ID: <49107D98.9080201@gmail.com> (raw)
In-Reply-To: <20081104162820.644b1487@lxorguk.ukuu.org.uk>

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Alan Cox wrote:
> On Tue, 04 Nov 2008 17:07:00 +0100
> Peter Zijlstra <peterz@infradead.org> wrote:
>> [snip]
>> I'm not sure how POSIX speaks of this.
>>
>> I think Linux does the expected thing.
> 
> I believe our behaviour is correct for mmap/mumap/truncate and it
> certainly used to be and was tested.
> 
> At the point you do anything involving mremap (which is non posix) our
> behaviour becomes rather bizarre.

Thanks to all for answers. I have made the conclusion that doing "open() new
file, truncate(<big size>), mmap(<the same big size>), write/read some memory
pages" should not populate other, untouched by write/read pages (until
MAP_POPULATE given), right?

-- 
Eugene V. Lyubimkin aka JackYF


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  reply	other threads:[~2008-11-04 16:52 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-03 21:57 mmap: is default non-populating behavior stable? Eugene V. Lyubimkin
2008-11-03 22:41 ` Peter Zijlstra
2008-11-03 22:41   ` Peter Zijlstra
2008-11-03 22:49   ` Rik van Riel
2008-11-03 22:49     ` Rik van Riel
2008-11-04 15:56     ` Chris Friesen
2008-11-04 15:56       ` Chris Friesen
2008-11-04 16:07       ` Peter Zijlstra
2008-11-04 16:07         ` Peter Zijlstra
2008-11-04 16:28         ` Alan Cox
2008-11-04 16:28           ` Alan Cox
2008-11-04 16:51           ` Eugene V. Lyubimkin [this message]
2008-11-05 16:42             ` Hugh Dickins
2008-11-05 16:42               ` Hugh Dickins
2008-11-05 16:54               ` Alan Cox
2008-11-05 16:54                 ` Alan Cox
2008-11-05 17:50               ` Eugene V. Lyubimkin
2008-11-05 23:31                 ` Hugh Dickins
2008-11-05 23:31                   ` Hugh Dickins

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