thp: madvise(MADV_NOHUGEPAGE)

Add madvise MADV_NOHUGEPAGE to mark regions that are not important to be
hugepage backed.  Return -EINVAL if the vma is not of an anonymous type,
or the feature isn't built into the kernel.  Never silently return
success.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 6 deletions

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 9b48c24df260..a8b7e42d19ec 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -52,10 +52,12 @@ extern pmd_t *page_check_address_pmd(struct page *page,
 #define HPAGE_PMD_SIZE HPAGE_SIZE
 
 #define transparent_hugepage_enabled(__vma)                             \
-        (transparent_hugepage_flags & (1<<TRANSPARENT_HUGEPAGE_FLAG) || \
-         (transparent_hugepage_flags &                                  \
-          (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG) &&                    \
-          (__vma)->vm_flags & VM_HUGEPAGE))
+        ((transparent_hugepage_flags &                                  \
+          (1<<TRANSPARENT_HUGEPAGE_FLAG) ||                             \
+          (transparent_hugepage_flags &                                 \
+           (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG) &&                   \
+           ((__vma)->vm_flags & VM_HUGEPAGE))) &&                       \
+         !((__vma)->vm_flags & VM_NOHUGEPAGE))
 #define transparent_hugepage_defrag(__vma)                              \
         ((transparent_hugepage_flags &                                  \
           (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)) ||                     \
@@ -103,7 +105,7 @@ extern void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd);
 #if HPAGE_PMD_ORDER > MAX_ORDER
 #error "hugepages can't be allocated by the buddy allocator"
 #endif
-extern int hugepage_madvise(unsigned long *vm_flags);
+extern int hugepage_madvise(unsigned long *vm_flags, int advice);
 extern void __vma_adjust_trans_huge(struct vm_area_struct *vma,
                                     unsigned long start,
                                     unsigned long end,
@@ -141,7 +143,7 @@ static inline int split_huge_page(struct page *page)
         do { } while (0)
 #define wait_split_huge_page(__anon_vma, __pmd) \
         do { } while (0)
-static inline int hugepage_madvise(unsigned long *vm_flags)
+static inline int hugepage_madvise(unsigned long *vm_flags, int advice)
 {
         BUG();
         return 0;