powerpc/mm/hash: Don't memset pgd table if not needed

[linux-2.6-block.git] / arch / powerpc / include / asm / book3s / 64 / pgalloc.h

diff --git a/arch/powerpc/include/asm/book3s/64/pgalloc.h b/arch/powerpc/include/asm/book3s/64/pgalloc.h
index 4746bc68d446d8e95427e67a86c3493a1d1f1668..558a159600adfbfe675a59d635a496e3ccae8742 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/pgalloc.h
+++ b/arch/powerpc/include/asm/book3s/64/pgalloc.h
@@ -80,8 +80,18 @@ static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 
        pgd = kmem_cache_alloc(PGT_CACHE(PGD_INDEX_SIZE),
                               pgtable_gfp_flags(mm, GFP_KERNEL));
+       /*
+        * With hugetlb, we don't clear the second half of the page table.
+        * If we share the same slab cache with the pmd or pud level table,
+        * we need to make sure we zero out the full table on alloc.
+        * With 4K we don't store slot in the second half. Hence we don't
+        * need to do this for 4k.
+        */
+#if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_PPC_64K_PAGES) && \
+       ((H_PGD_INDEX_SIZE == H_PUD_CACHE_INDEX) ||                  \
+        (H_PGD_INDEX_SIZE == H_PMD_CACHE_INDEX))
        memset(pgd, 0, PGD_TABLE_SIZE);
-
+#endif
        return pgd;
 }