Re: [Xen-devel] [PATCH RESEND] xen/gntdev: Grant maps should not be subject to NUMA balancing

[Boris Ostrovsky]

On 11/10/2016 12:49 PM, David Vrabel wrote:
> On 10/11/16 17:47, Olaf Hering wrote:
>> On Thu, Nov 10, Boris Ostrovsky wrote:
>>
>>> Are you sure it's this patch that causes the failure?
>>>
>>> I commented out '| VM_IO' and still unable to boot with this option.
>> Yes, this works for me, sles12sp2 dom0+domU, which is linux-4.4 based:

I've never tested on 4.4, this was added for 4.5 (with CC to stable#4.4)
and now I am testing on 4.7)

>>
>> +++ 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 | VM_IO;
>> +       vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP /*| VM_IO*/;
>>  
>>         if (use_ptemod)
>>                 vma->vm_flags |= VM_DONTCOPY;
> I think we need a custom policy for this VMA with MPOL_F_MOF cleared.

I think you are right, I remember when I was looking at this adding a
policy was the other option. Let me look at this again.


-boris