Re: [RFC/PATCH 20/22] s390/mm: Enable gmap huge pmd support

David Hildenbrand
2017-11-15T10:08:08Z

On 06.11.2017 23:29, Janosch Frank wrote:
> Now that we have everything in place, let's allow huge pmds for gmap
> linking, effectively allowing huge pages guests.

Can you add a comment about transparent huge pages?

Reviewed-by: David Hildenbrand <david@redhat.com>

>
> Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
> ---
> arch/s390/mm/gmap.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
> index 430dcd9..3cc2765 100644
> --- a/arch/s390/mm/gmap.c
> +++ b/arch/s390/mm/gmap.c
> @@ -1,8 +1,10 @@
> /*
> * KVM guest address space mapping code
> *
> - * Copyright IBM Corp. 2007, 2016
> + * Copyright IBM Corp. 2007, 2016, 2017
> * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
> + * David Hildenbrand <david@redhat.com>
> + * Janosch Frank <frankja@linux.vnet.ibm.com>
> */
>
> #include <linux/kernel.h>
> @@ -596,9 +598,6 @@ int __gmap_link(struct gmap *gmap, unsigned long gaddr, unsigned long vmaddr)
> return -EFAULT;
> pmd = pmd_offset(pud, vmaddr);
> VM_BUG_ON(pmd_none(*pmd));
> - /* large pmds cannot yet be handled */
> - if (pmd_large(*pmd))
> - return -EFAULT;
> /* Link gmap segment table entry location to page table. */
> rc = radix_tree_preload(GFP_KERNEL);
> if (rc)
>

--

Thanks,

David / dhildenb