Date: Thu, 29 Jan 2009 09:05:07 +0100
From: Frank Mehnert <Frank.Mehnert@Sun.COM>
Subject: PFs on pages pinned with get_user_pages()
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Message-id: <200901290905.10966.frank.mehnert@sun.com>
Organization: Sun Microsystems
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Hi,

please could someone explain me under which circumstances a pagefault,
either generated from kernel code or from userland code, can occur on
pages which are pinned with get_user_pages()?

So far my understanding was that this can _never_ happen but I seems to
be wrong. Under high memory pressure I get PFs on such pages raised from
kernel code and the PFs are handled by do_swap_page(). When this happens,
page_count is 3 but page_mapped() returns false.

Thanks in advance,

=46rank
=2D-=20
Dr.-Ing. Frank Mehnert    Sun Microsystems    http://www.sun.com/

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