• Dan Williams's avatar
    mm, powerpc: use vma_kernel_pagesize() in vma_mmu_pagesize() · 09135cc5
    Dan Williams authored
    Patch series "mm, smaps: MMUPageSize for device-dax", v3.
    Similar to commit 31383c68 ("mm, hugetlbfs: introduce ->split() to
    vm_operations_struct") here is another occasion where we want
    special-case hugetlbfs/hstate enabling to also apply to device-dax.
    This prompts the question what other hstate conversions we might do
    beyond ->split() and ->pagesize(), but this appears to be the last of
    the usages of hstate_vma() in generic/non-hugetlbfs specific code paths.
    This patch (of 3):
    The current powerpc definition of vma_mmu_pagesize() open codes looking
    up the page size via hstate.  It is identical to the generic
    vma_kernel_pagesize() implementation.
    Now, vma_kernel_pagesize() is growing support for determining the page
    size of Device-DAX vmas in addition to the existing Hugetlbfs page size
    Ideally, if the powerpc vma_mmu_pagesize() used vma_kernel_pagesize() it
    would automatically benefit from any new vma-type support that is added
    to vma_kernel_pagesize().  However, the powerpc vma_mmu_pagesize() is
    prevented from calling vma_kernel_pagesize() due to a circular header
    dependency that requires vma_mmu_pagesize() to be defined before
    including <linux/hugetlb.h>.
    Break this circular dependency by defining the default vma_mmu_pagesize()
    as a __weak symbol to be overridden by the powerpc version.
    Link: http://lkml.kernel.org/r/151996254179.27922.2213728278535578744.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by: default avatarDan Williams <dan.j.williams@intel.com>
    Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Paul Mackerras <paulus@samba.org>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Jane Chu <jane.chu@oracle.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
hugetlbpage.c 21.6 KB