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    SubjectRe: [PATCH v2] tmpfs not interleaving properly
    On Thu, May 31, 2012 at 04:35:53PM -0400, KOSAKI Motohiro wrote:
    > (5/31/12 4:25 PM), Andrew Morton wrote:
    >> On Thu, 31 May 2012 16:09:15 -0400
    >> KOSAKI Motohiro<kosaki.motohiro@gmail.com> wrote:
    >>
    >>>> --- a/mm/shmem.c
    >>>> +++ b/mm/shmem.c
    >>>> @@ -929,7 +929,7 @@ static struct page *shmem_alloc_page(gfp_t gfp,
    >>>> /*
    >>>> * alloc_page_vma() will drop the shared policy reference
    >>>> */
    >>>> - return alloc_page_vma(gfp,&pvma, 0);
    >>>> + return alloc_page_vma(gfp,&pvma, info->node_offset<< PAGE_SHIFT );
    >>>
    >>> 3rd argument of alloc_page_vma() is an address. This is type error.
    >>
    >> Well, it's an unsigned long...
    >>
    >> But yes, it is conceptually wrong and *looks* weird. I think we can
    >> address that by overcoming our peculair aversion to documenting our
    >> code, sigh. This?
    >
    > Sorry, no.
    >
    > addr agrument of alloc_pages_vma() have two meanings.
    >
    > 1) interleave node seed
    > 2) look-up key of shmem policy
    >
    > I think this patch break (2). shmem_get_policy(pol, addr) assume caller honor to
    > pass correct address.

    But the pseudo vma we generated in shmem_alloc_page the vm_ops are set to NULL.
    So get_vma_policy will return the policy provided by the pseudo vma and not reach
    the shmem_get_policy.



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