xen/gntdev: Grant maps should not be subject to NUMA balancing (Closes: #810472)

debian/changelog

@@ -5,6 +5,8 @@ linux (4.3.3-6) UNRELEASED; urgency=medium
   * genorig.py: Make orig tarballs really reproducible:
     - Override umask while extracting/exporting files
     - Override user and group names in tarball
+  * xen/gntdev: Grant maps should not be subject to NUMA balancing
+    (Closes: #810472)
 
  -- Ben Hutchings <ben@decadent.org.uk>  Fri, 08 Jan 2016 12:08:13 +0000
 

debian/patches/bugfix/all/xen-gntdev-grant-maps-should-not-be-subject-to-numa-.patch

@@ -0,0 +1,38 @@
+From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
+Date: Tue, 10 Nov 2015 15:10:33 -0500
+Subject: xen/gntdev: Grant maps should not be subject to NUMA balancing
+Origin: https://git.kernel.org/linus/9c17d96500f78d7ecdb71ca6942830158bc75a2b
+Bug-Debian: https://bugs.debian.org/810472
+
+Doing so will cause the grant to be unmapped and then, during
+fault handling, the fault to be mistakenly treated as NUMA hint
+fault.
+
+In addition, even if those maps could partcipate in NUMA
+balancing, it wouldn't provide any benefit since we are unable
+to determine physical page's node (even if/when VNUMA is
+implemented).
+
+Marking grant maps' VMAs as VM_IO will exclude them from being
+part of NUMA balancing.
+
+Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
+Cc: stable@vger.kernel.org
+Signed-off-by: David Vrabel <david.vrabel@citrix.com>
+---
+ drivers/xen/gntdev.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
+index 2ea0b3b..1be5dd0 100644
+--- a/drivers/xen/gntdev.c
++++ b/drivers/xen/gntdev.c
+@@ -804,7 +804,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
+ 
+ 	vma->vm_ops = &gntdev_vmops;
+ 
+-	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
++	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
+ 
+ 	if (use_ptemod)
+ 		vma->vm_flags |= VM_DONTCOPY;

debian/patches/series

@@ -133,3 +133,4 @@ bugfix/all/drm-nouveau-pmu-do-not-assume-a-pmu-is-present.patch
 bugfix/x86/drm-i915-don-t-compare-has_drrs-strictly-in-pipe-con.patch
 bugfix/arm/crypto-sun4i-ss-add-missing-statesize.patch
 bugfix/all/revert-xhci-don-t-finish-a-td-if-we-get-a-short-transfer.patch
+bugfix/all/xen-gntdev-grant-maps-should-not-be-subject-to-numa-.patch