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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2013-06-20 14:30:26 +0530
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-06-21 16:01:58 +1000
commit437d496457a30ce9ccccb94b2373c201b2558392 (patch)
tree401857d741564eff170764518ed5acbeacc43f63 /arch/powerpc/mm
parentd8e355a20f9dd45deea4c33db649dda59bdbd293 (diff)
powerpc/THP: Enable THP on PPC64
We enable only if the we support 16MB page size. Reviewed-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/mm')
-rw-r--r--arch/powerpc/mm/pgtable_64.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index e4d3e9fb59be..074a4a225054 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -831,4 +831,33 @@ pmd_t pmdp_get_and_clear(struct mm_struct *mm,
memset(pgtable, 0, PTE_FRAG_SIZE);
return old_pmd;
}
+
+int has_transparent_hugepage(void)
+{
+ if (!mmu_has_feature(MMU_FTR_16M_PAGE))
+ return 0;
+ /*
+ * We support THP only if PMD_SIZE is 16MB.
+ */
+ if (mmu_psize_defs[MMU_PAGE_16M].shift != PMD_SHIFT)
+ return 0;
+ /*
+ * We need to make sure that we support 16MB hugepage in a segement
+ * with base page size 64K or 4K. We only enable THP with a PAGE_SIZE
+ * of 64K.
+ */
+ /*
+ * If we have 64K HPTE, we will be using that by default
+ */
+ if (mmu_psize_defs[MMU_PAGE_64K].shift &&
+ (mmu_psize_defs[MMU_PAGE_64K].penc[MMU_PAGE_16M] == -1))
+ return 0;
+ /*
+ * Ok we only have 4K HPTE
+ */
+ if (mmu_psize_defs[MMU_PAGE_4K].penc[MMU_PAGE_16M] == -1)
+ return 0;
+
+ return 1;
+}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */