From: Andi Kleen <andi@firstfloor.org>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: "dean gaudet" <dean@arctic.org>,
"Nick Piggin" <nickpiggin@yahoo.com.au>,
Xen-devel <xen-devel@lists.xensource.com>,
Morten@suse.de, "David Chinner" <dgc@sgi.com>,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
Bøgeskov <xen-users@morten.bogeskov.dk>,
xfs@oss.sgi.com, xfs-masters@oss.sgi.com,
"Mark Williamson" <mark.williamson@cl.cam.ac.uk>
Subject: Re: Interaction between Xen and XFS: stray RW mappings
Date: Mon, 22 Oct 2007 15:47:27 +0200 [thread overview]
Message-ID: <p73sl439s7k.fsf@bingen.suse.de> (raw)
In-Reply-To: <471C1A61.1010001@goop.org> (Jeremy Fitzhardinge's message of "Sun\, 21 Oct 2007 20\:34\:57 -0700")
Jeremy Fitzhardinge <jeremy@goop.org> writes:
>
> Yes, that's precisely the problem. xfs does delay the unmap, leaving
> stray mappings, which upsets Xen.
Again it not just upsets Xen, keeping mappings to freed pages is wrong generally
and violates the x86 (and likely others like PPC) architecture because it can
cause illegal caching attribute aliases.
The patch that went into the tree was really not correct -- this
bogus optimization should have been unconditionally removed
or if you really wanted an ifdef made dependent on !CONFIG_XEN &&
!CONFIG_AGP (and likely && !CONFIG_DRM && !CONFIG_anything else that
uses uncached mappings in memory).
You just worked around the obvious failure and leave the non obvious
rare corruptions in, which isn't a good strategy.
-Andi
next prev parent reply other threads:[~2007-10-22 13:47 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-12 16:58 Interaction between Xen and XFS: stray RW mappings Jeremy Fitzhardinge
2007-10-12 17:08 ` Jeremy Fitzhardinge
2007-10-14 22:56 ` David Chinner
2007-10-14 23:12 ` Jeremy Fitzhardinge
2007-10-14 23:33 ` David Chinner
2007-10-15 4:15 ` Nick Piggin
2007-10-15 0:57 ` Jeremy Fitzhardinge
2007-10-15 7:26 ` Nick Piggin
2007-10-15 3:42 ` Jeremy Fitzhardinge
2007-10-15 4:11 ` David Chinner
2007-10-15 4:18 ` Jeremy Fitzhardinge
2007-10-15 4:25 ` David Chinner
2007-10-15 8:31 ` [xfs-masters] " Christoph Hellwig
2007-10-22 3:18 ` dean gaudet
2007-10-22 3:34 ` Jeremy Fitzhardinge
2007-10-22 4:28 ` dean gaudet
2007-10-22 4:39 ` Nick Piggin
2007-10-22 18:37 ` Jeremy Fitzhardinge
2007-10-22 18:32 ` Jeremy Fitzhardinge
2007-10-22 13:47 ` Andi Kleen [this message]
2007-10-22 18:40 ` Jeremy Fitzhardinge
2007-10-22 19:07 ` Andi Kleen
2007-10-22 19:11 ` Jeremy Fitzhardinge
2007-10-22 22:32 ` David Chinner
2007-10-22 23:35 ` Andi Kleen
2007-10-23 0:16 ` Zachary Amsden
2007-10-23 0:36 ` David Chinner
2007-10-23 7:04 ` [patch] " David Chinner
2007-10-23 9:30 ` Andi Kleen
2007-10-23 12:41 ` David Chinner
2007-10-23 14:33 ` Jeremy Fitzhardinge
2007-10-24 4:36 ` [PATCH] Allow lazy unmapping by taking extra page references V2 David Chinner
2007-10-24 5:08 ` Jeremy Fitzhardinge
2007-10-24 21:48 ` [PATCH] Allow lazy unmapping by taking extra page references V3 David Chinner
2007-10-24 22:46 ` Jeremy Fitzhardinge
2007-10-24 23:21 ` David Chinner
2007-10-23 9:28 ` Interaction between Xen and XFS: stray RW mappings Andi Kleen
2007-10-15 9:36 ` Andi Kleen
2007-10-15 14:56 ` Nick Piggin
2007-10-15 11:07 ` Andi Kleen
2007-10-15 11:28 ` Nick Piggin
2007-10-15 12:54 ` Andi Kleen
2007-10-21 12:17 ` Dave Airlie
2007-10-21 22:16 ` Benjamin Herrenschmidt
2007-10-22 9:49 ` Andi Kleen
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