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Commit b96375f7 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

mm: add a pmd_fault handler 



Allow non-anonymous VMAs to provide huge pages in response to a page fault.

Signed-off-by: default avatarMatthew Wilcox <willy@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4897c765

include/linux/mm.h

+2 −0
Original line number Original line Diff line number Diff line
@@ -249,6 +249,8 @@ struct vm_operations_struct { 
	void (*close)(struct vm_area_struct * area);

	void (*close)(struct vm_area_struct * area);

	int (*mremap)(struct vm_area_struct * area);

	int (*mremap)(struct vm_area_struct * area);

	int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);

	int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);

	int (*pmd_fault)(struct vm_area_struct *, unsigned long address,

						pmd_t *, unsigned int flags);

	void (*map_pages)(struct vm_area_struct *vma, struct vm_fault *vmf);

	void (*map_pages)(struct vm_area_struct *vma, struct vm_fault *vmf);





	/* notification that a previously read-only page is about to become

	/* notification that a previously read-only page is about to become

mm/memory.c

+24 −6
Original line number Original line Diff line number Diff line
@@ -3232,6 +3232,27 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, 
	return 0;

	return 0;

}

}





static int create_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,

			unsigned long address, pmd_t *pmd, unsigned int flags)

{

	if (!vma->vm_ops)

		return do_huge_pmd_anonymous_page(mm, vma, address, pmd, flags);

	if (vma->vm_ops->pmd_fault)

		return vma->vm_ops->pmd_fault(vma, address, pmd, flags);

	return VM_FAULT_FALLBACK;

}



static int wp_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma,

			unsigned long address, pmd_t *pmd, pmd_t orig_pmd,

			unsigned int flags)

{

	if (!vma->vm_ops)

		return do_huge_pmd_wp_page(mm, vma, address, pmd, orig_pmd);

	if (vma->vm_ops->pmd_fault)

		return vma->vm_ops->pmd_fault(vma, address, pmd, flags);

	return VM_FAULT_FALLBACK;

}



/*

/*

 * These routines also need to handle stuff like marking pages dirty

 * These routines also need to handle stuff like marking pages dirty

 * and/or accessed for architectures that don't do it in hardware (most

 * and/or accessed for architectures that don't do it in hardware (most
@@ -3334,10 +3355,7 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, 
	if (!pmd)

	if (!pmd)

		return VM_FAULT_OOM;

		return VM_FAULT_OOM;

	if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {

	if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {

		int ret = VM_FAULT_FALLBACK;

		int ret = create_huge_pmd(mm, vma, address, pmd, flags);

		if (!vma->vm_ops)

			ret = do_huge_pmd_anonymous_page(mm, vma, address,

					pmd, flags);

		if (!(ret & VM_FAULT_FALLBACK))

		if (!(ret & VM_FAULT_FALLBACK))

			return ret;

			return ret;

	} else {

	} else {
@@ -3361,8 +3379,8 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, 
							     orig_pmd, pmd);

							     orig_pmd, pmd);





			if (dirty && !pmd_write(orig_pmd)) {

			if (dirty && !pmd_write(orig_pmd)) {

				ret = do_huge_pmd_wp_page(mm, vma, address, pmd,

				ret = wp_huge_pmd(mm, vma, address, pmd,

							  orig_pmd);

							orig_pmd, flags);

				if (!(ret & VM_FAULT_FALLBACK))

				if (!(ret & VM_FAULT_FALLBACK))

					return ret;

					return ret;

			} else {

			} else {