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mm: add a pmd_fault handler

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

Signed-off-by: Matthew 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthew Wilcox 2015-09-08 14:58:48 -07:00 committed by Linus Torvalds
parent 4897c7655d
commit b96375f74a
2 changed files with 26 additions and 6 deletions
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2
include/linux/mm.h
View File

@ -249,6 +249,8 @@ struct vm_operations_struct {
void (*close)(struct vm_area_struct * area);
int (*mremap)(struct vm_area_struct * area);
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);
/* notification that a previously read-only page is about to become

30
mm/memory.c
View File

@ -3232,6 +3232,27 @@ out:
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
* 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)
return VM_FAULT_OOM;
if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
int ret = VM_FAULT_FALLBACK;
if (!vma->vm_ops)
ret = do_huge_pmd_anonymous_page(mm, vma, address,
pmd, flags);
int ret = create_huge_pmd(mm, vma, address, pmd, flags);
if (!(ret & VM_FAULT_FALLBACK))
return ret;
} else {
@ -3361,8 +3379,8 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
orig_pmd, pmd);
if (dirty && !pmd_write(orig_pmd)) {
ret = do_huge_pmd_wp_page(mm, vma, address, pmd,
orig_pmd);
ret = wp_huge_pmd(mm, vma, address, pmd,
orig_pmd, flags);
if (!(ret & VM_FAULT_FALLBACK))
return ret;
} else {