Attachment 288841 Details for Bug 339621 – linux-2.6.18-xen 263:9bf1ddd0f6bf ported to 2.6.18-53.el5

[patch] linux-2.6.18-xen 263:9bf1ddd0f6bf ported to 2.6.18-53.el5

linux-2.6.18-xen-263-9bf1ddd0f6bf (text/plain), 2.04 KB, created by Ian Campbell on 2007-12-14 09:21:28 UTC

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Creator: Ian Campbell

Created: 2007-12-14 09:21:28 UTC

Size: 2.04 KB

patch

obsolete

># HG changeset patch
># User Ian Campbell <ian.campbell@xensource.com>
># Date 1192609443 -3600
># Node ID 9bf1ddd0f6bf57684c5b0307a43ea381c45f5147
># Parent  ff61d4335750af17daccbadfa5478e9200d1e09d
>xfs: eagerly remove vmap mappings to avoid upsetting Xen
>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.  David Chinner says this shouldn't
>have any performance impact on filesystems with default block sizes;
>it will only affect filesystems with large block sizes.
>
>Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
>Acked-by: David Chinner <dgc@sgi.com>
>Cc: Nick Piggin <nickpiggin@yahoo.com.au>
>Cc: XFS masters <xfs-masters@oss.sgi.com>
>Cc: Stable kernel <stable@kernel.org>
>Cc: Morten =?utf-8?q?B=C3=B8geskov?= <xen-users@morten.bogeskov.dk>
>Cc: Mark Williamson <mark.williamson@cl.cam.ac.uk>
>
>---
> fs/xfs/linux-2.6/xfs_buf.c |   13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
>===================================================================
>linux-2.6.18-xen changeset: 263:9bf1ddd0f6bf57684c5b0307a43ea381c45f5147
>linux-2.6.18-xen date: Wed Oct 17 09:24:03 2007 +0100
>
>diff -r ff61d4335750 -r 9bf1ddd0f6bf fs/xfs/linux-2.6/xfs_buf.c
>--- a/fs/xfs/linux-2.6/xfs_buf.c	Tue Oct 16 09:34:20 2007 +0100
>+++ b/fs/xfs/linux-2.6/xfs_buf.c	Wed Oct 17 09:24:03 2007 +0100
>@@ -181,6 +181,19 @@ free_address(
> 	void		*addr)
> {
> 	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)) {

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Attachments on bug 339621: 288831 | 288841