mm/hugetlb: clean up ARCH_HAS_GIGANTIC_PAGE

This moves the #ifdef in C code to a Kconfig dependency.  Also we move
the gigantic_page_supported() function to be arch specific.

This allows architectures to conditionally enable runtime allocation of
gigantic huge page.  Architectures like ppc64 supports different
gigantic huge page size (16G and 1G) based on the translation mode
selected.  This provides an opportunity for ppc64 to enable runtime
allocation only w.r.t 1G hugepage.

No functional change in this patch.

Link: http://lkml.kernel.org/r/1494995292-4443-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9f7a934..ff925ec 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -13,7 +13,7 @@ config ARM64
        select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
        select ARCH_HAS_ELF_RANDOMIZE
        select ARCH_HAS_GCOV_PROFILE_ALL
-       select ARCH_HAS_GIGANTIC_PAGE
+       select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
        select ARCH_HAS_KCOV
        select ARCH_HAS_SET_MEMORY
        select ARCH_HAS_SG_CHAIN

diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/hugetlb.h
index bbc1e35..793bd73 100644 (file)
--- a/arch/arm64/include/asm/hugetlb.h
+++ b/arch/arm64/include/asm/hugetlb.h
@@ -83,4 +83,8 @@ extern void huge_ptep_set_wrprotect(struct mm_struct *mm,
 extern void huge_ptep_clear_flush(struct vm_area_struct *vma,
                                  unsigned long addr, pte_t *ptep);
 
+#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
+static inline bool gigantic_page_supported(void) { return true; }
+#endif
+
 #endif /* __ASM_HUGETLB_H */

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 37abe86..7eeb75d 100644 (file)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -68,7 +68,7 @@ config S390
        select ARCH_HAS_DEVMEM_IS_ALLOWED
        select ARCH_HAS_ELF_RANDOMIZE
        select ARCH_HAS_GCOV_PROFILE_ALL
-       select ARCH_HAS_GIGANTIC_PAGE
+       select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
        select ARCH_HAS_KCOV
        select ARCH_HAS_SET_MEMORY
        select ARCH_HAS_SG_CHAIN

diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
index cd546a2..89057b2 100644 (file)
--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -112,4 +112,7 @@ static inline pte_t huge_pte_modify(pte_t pte, pgprot_t newprot)
        return pte_modify(pte, newprot);
 }
 
+#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
+static inline bool gigantic_page_supported(void) { return true; }
+#endif
 #endif /* _ASM_S390_HUGETLB_H */

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1dbbe38..fe53a3a 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -22,7 +22,7 @@ config X86_64
        def_bool y
        depends on 64BIT
        # Options that are inherently 64-bit kernel only:
-       select ARCH_HAS_GIGANTIC_PAGE
+       select ARCH_HAS_GIGANTIC_PAGE if (MEMORY_ISOLATION && COMPACTION) || CMA
        select ARCH_SUPPORTS_INT128
        select ARCH_USE_CMPXCHG_LOCKREF
        select HAVE_ARCH_SOFT_DIRTY

diff --git a/arch/x86/include/asm/hugetlb.h b/arch/x86/include/asm/hugetlb.h
index 3a10616..535af0f 100644 (file)
--- a/arch/x86/include/asm/hugetlb.h
+++ b/arch/x86/include/asm/hugetlb.h
@@ -85,4 +85,8 @@ static inline void arch_clear_hugepage_flags(struct page *page)
 {
 }
 
+#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
+static inline bool gigantic_page_supported(void) { return true; }
+#endif
+
 #endif /* _ASM_X86_HUGETLB_H */

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3326373..c73828e 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1040,9 +1040,7 @@ static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
                ((node = hstate_next_node_to_free(hs, mask)) || 1);     \
                nr_nodes--)
 
-#if defined(CONFIG_ARCH_HAS_GIGANTIC_PAGE) && \
-       ((defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || \
-       defined(CONFIG_CMA))
+#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
 static void destroy_compound_gigantic_page(struct page *page,
                                        unsigned int order)
 {
@@ -1174,8 +1172,7 @@ static int alloc_fresh_gigantic_page(struct hstate *h,
        return 0;
 }
 
-static inline bool gigantic_page_supported(void) { return true; }
-#else
+#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
 static inline bool gigantic_page_supported(void) { return false; }
 static inline void free_gigantic_page(struct page *page, unsigned int order) { }
 static inline void destroy_compound_gigantic_page(struct page *page,