Messages in this thread Patch in this message | | | Date | Wed, 14 Nov 2007 22:15:06 -0800 | From | Greg KH <> | Subject | [patch 14/19] xfs: eagerly remove vmap mappings to avoid upsetting Xen |
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-stable review patch. If anyone has any objections, please let us know.
------------------ From: Jeremy Fitzhardinge <jeremy@goop.org>
patch ace2e92e193126711cb3a83a3752b2c5b8396950 in mainline.
XFS leaves stray mappings around when it vmaps memory to make it virtually contigious. This upsets Xen if one of those pages is being recycled into a pagetable, since it finds an extra writable mapping of the page.
This patch solves the problem in a brute force way, by making XFS always eagerly unmap its mappings.
[ Stable: This works around a bug in 2.6.23. We may come up with a better solution for mainline, but this seems like a low-impact fix for the stable kernel. ]
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: XFS masters <xfs-masters@oss.sgi.com> Cc: Morten =?utf-8?q?B=C3=B8geskov?= <xen-users@morten.bogeskov.dk> Cc: Mark Williamson <mark.williamson@cl.cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/xfs/linux-2.6/xfs_buf.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
--- a/fs/xfs/linux-2.6/xfs_buf.c +++ b/fs/xfs/linux-2.6/xfs_buf.c @@ -187,6 +187,19 @@ free_address( { a_list_t *aentry; +#ifdef CONFIG_XEN + /* + * Xen needs to be able to make sure it can get an exclusive + * RO mapping of pages it wants to turn into a pagetable. If + * a newly allocated page is also still being vmap()ed by xfs, + * it will cause pagetable construction to fail. This is a + * quick workaround to always eagerly unmap pages so that Xen + * is happy. + */ + vunmap(addr); + return; +#endif + aentry = kmalloc(sizeof(a_list_t), GFP_NOWAIT); if (likely(aentry)) { spin_lock(&as_lock); -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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