From: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Allow non-anonymous VMAs to provide huge pages in response to a page fault.
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
---
include/linux/mm.h | 2 ++
mm/memory.c | 15 +++++++++++----
2 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d0de9fa..c0b4f74 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -229,6 +229,8 @@ struct vm_operations_struct {
void (*open)(struct vm_area_struct * area);
void (*close)(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
diff --git a/mm/memory.c b/mm/memory.c
index 993be2b..ec51b0f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3238,6 +3238,16 @@ 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;
+}
+
/*
* These routines also need to handle stuff like marking pages dirty
* and/or accessed for architectures that don't do it in hardware (most
@@ -3335,10 +3345,7 @@ 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 {
--
2.1.0
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