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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-03-01 07:15:14 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-03-03 13:18:29 +0300 |
| commit | ff20c2e0acc5ad7e27c68592ade135efee399549 (patch) | |
| tree | ba2078e9b2def032e9722112e5ab9d82b5ac0de3 /arch | |
| parent | 368ced78e6ed3d72c2acc61233b58487071ec289 (diff) | |
| download | linux-ff20c2e0acc5ad7e27c68592ade135efee399549.tar.xz | |
mm: Some arch may want to use HPAGE_PMD related values as variables
With next generation power processor, we are having a new mmu model
[1] that require us to maintain a different linux page table format.
Inorder to support both current and future ppc64 systems with a single
kernel we need to make sure kernel can select between different page
table format at runtime. With the new MMU (radix MMU) added, we will
have two different pmd hugepage size 16MB for hash model and 2MB for
Radix model. Hence make HPAGE_PMD related values as a variable.
Actual conversion of HPAGE_PMD to a variable for ppc64 happens in a
followup patch.
[1] http://ibm.biz/power-isa3 (Needs registration).
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/mm/pgtable_64.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index af304e6d5a89..0eb53128ca2a 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -817,6 +817,13 @@ pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, int has_transparent_hugepage(void) { + + BUILD_BUG_ON_MSG((PMD_SHIFT - PAGE_SHIFT) >= MAX_ORDER, + "hugepages can't be allocated by the buddy allocator"); + + BUILD_BUG_ON_MSG((PMD_SHIFT - PAGE_SHIFT) < 2, + "We need more than 2 pages to do deferred thp split"); + if (!mmu_has_feature(MMU_FTR_16M_PAGE)) return 0; /* |