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| author | Boris Ostrovsky <boris.ostrovsky@oracle.com> | 2016-11-21 17:56:06 +0300 |
|---|---|---|
| committer | Juergen Gross <jgross@suse.com> | 2016-11-28 16:14:05 +0300 |
| commit | 30faaafdfa0c754c91bac60f216c9f34a2bfdf7e (patch) | |
| tree | 2a498846f2fa8e0f62016df566cc0f33afbebae2 /drivers/xen/gntdev.c | |
| parent | 1eb08545c0a3a2249ad53e393383cc06163d0d16 (diff) | |
| download | linux-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.c | 2 |
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; |