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authorBoris Ostrovsky <boris.ostrovsky@oracle.com>2016-11-21 17:56:06 +0300
committerJuergen Gross <jgross@suse.com>2016-11-28 16:14:05 +0300
commit30faaafdfa0c754c91bac60f216c9f34a2bfdf7e (patch)
tree2a498846f2fa8e0f62016df566cc0f33afbebae2 /drivers/xen/gntdev.c
parent1eb08545c0a3a2249ad53e393383cc06163d0d16 (diff)
downloadlinux-30faaafdfa0c754c91bac60f216c9f34a2bfdf7e.tar.xz
xen/gntdev: Use VM_MIXEDMAP instead of VM_IO to avoid NUMA balancing
Commit 9c17d96500f7 ("xen/gntdev: Grant maps should not be subject to NUMA balancing") set VM_IO flag to prevent grant maps from being subjected to NUMA balancing. It was discovered recently that this flag causes get_user_pages() to always fail with -EFAULT. check_vma_flags __get_user_pages __get_user_pages_locked __get_user_pages_unlocked get_user_pages_fast iov_iter_get_pages dio_refill_pages do_direct_IO do_blockdev_direct_IO do_blockdev_direct_IO ext4_direct_IO_read generic_file_read_iter aio_run_iocb (which can happen if guest's vdisk has direct-io-safe option). To avoid this let's use VM_MIXEDMAP flag instead --- it prevents NUMA balancing just as VM_IO does and has no effect on check_vma_flags(). Cc: stable@vger.kernel.org Reported-by: Olaf Hering <olaf@aepfle.de> Suggested-by: Hugh Dickins <hughd@google.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Acked-by: Hugh Dickins <hughd@google.com> Tested-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/xen/gntdev.c')
-rw-r--r--drivers/xen/gntdev.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index bb952121ea94..2ef2b61b69df 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -1007,7 +1007,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
vma->vm_ops = &gntdev_vmops;
- vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_IO;
+ vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
if (use_ptemod)
vma->vm_flags |= VM_DONTCOPY;