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Commit 0af4e98b authored by Andrea Arcangeli's avatar Andrea Arcangeli Committed by Linus Torvalds
Browse files

thp: madvise(MADV_HUGEPAGE) 



Add madvise MADV_HUGEPAGE to mark regions that are 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: default avatarAndrea Arcangeli <aarcange@redhat.com>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f66055ab

include/linux/huge_mm.h

+6 −0
Original line number Diff line number Diff line
@@ -97,6 +97,7 @@ 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);

#else /* CONFIG_TRANSPARENT_HUGEPAGE */

#define HPAGE_PMD_SHIFT ({ BUG(); 0; })

#define HPAGE_PMD_MASK ({ BUG(); 0; })
@@ -113,6 +114,11 @@ 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)

{

	BUG();

	return 0;

}

#endif /* CONFIG_TRANSPARENT_HUGEPAGE */



#endif /* _LINUX_HUGE_MM_H */

mm/huge_memory.c

+16 −0
Original line number Diff line number Diff line
@@ -896,6 +896,22 @@ int split_huge_page(struct page *page) 
	return ret;

}



int hugepage_madvise(unsigned long *vm_flags)

{

	/*

	 * Be somewhat over-protective like KSM for now!

	 */

	if (*vm_flags & (VM_HUGEPAGE | VM_SHARED  | VM_MAYSHARE   |

			 VM_PFNMAP   | VM_IO      | VM_DONTEXPAND |

			 VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE |

			 VM_MIXEDMAP | VM_SAO))

		return -EINVAL;



	*vm_flags |= VM_HUGEPAGE;



	return 0;

}



void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd)

{

	struct page *page;

mm/madvise.c

+8 −0
Original line number Diff line number Diff line
@@ -71,6 +71,11 @@ static long madvise_behavior(struct vm_area_struct * vma, 
		if (error)

			goto out;

		break;

	case MADV_HUGEPAGE:

		error = hugepage_madvise(&new_flags);

		if (error)

			goto out;

		break;

	}



	if (new_flags == vma->vm_flags) {
@@ -282,6 +287,9 @@ madvise_behavior_valid(int behavior) 
#ifdef CONFIG_KSM

	case MADV_MERGEABLE:

	case MADV_UNMERGEABLE:

#endif

#ifdef CONFIG_TRANSPARENT_HUGEPAGE

	case MADV_HUGEPAGE:

#endif

		return 1;