The patch titled
Subject: mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct
has been added to the -mm tree. Its filename is
mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct.patch
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------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm, hugetlbfs: introduce ->pagesize() to vm_operations_struct
When device-dax is operating in huge-page mode we want it to behave like
hugetlbfs and report the MMU page mapping size that is being enforced by
the vma. Similar to 31383c6865a5 ("mm, hugetlbfs: introduce ->split() to
vm_operations_struct") it would be messy to teach vma_mmu_pagesize() about
device-dax page mapping sizes in the same (hstate) way that hugetlbfs
communicates this attribute. Instead, these patches introduce a new
->pagesize() vm operation.
Link: http://lkml.kernel.org/r/151270385525.21215.16828596212056611775.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reported-by: Jane Chu <jane.chu@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/mm/hugetlbpage.c | 5 ----
include/linux/hugetlb.h | 30 ++++++++++++++++++++-----
include/linux/mm.h | 1
mm/hugetlb.c | 38 ++++++--------------------------
4 files changed, 34 insertions(+), 40 deletions(-)
diff -puN arch/powerpc/mm/hugetlbpage.c~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct arch/powerpc/mm/hugetlbpage.c
--- a/arch/powerpc/mm/hugetlbpage.c~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct
+++ a/arch/powerpc/mm/hugetlbpage.c
@@ -568,10 +568,7 @@ unsigned long vma_mmu_pagesize(struct vm
if (!radix_enabled())
return 1UL << mmu_psize_to_shift(psize);
#endif
- if (!is_vm_hugetlb_page(vma))
- return PAGE_SIZE;
-
- return huge_page_size(hstate_vma(vma));
+ return vma_kernel_pagesize(vma);
}
static inline bool is_power_of_4(unsigned long x)
diff -puN include/linux/hugetlb.h~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct include/linux/hugetlb.h
--- a/include/linux/hugetlb.h~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct
+++ a/include/linux/hugetlb.h
@@ -253,6 +253,30 @@ enum {
HUGETLB_ANONHUGE_INODE = 2,
};
+/*
+ * Return the size of the pages allocated when backing a VMA. In the majority
+ * cases this will be same size as used by the page table entries.
+ */
+static inline unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
+{
+ if (vma->vm_ops && vma->vm_ops->pagesize)
+ return vma->vm_ops->pagesize(vma);
+ return PAGE_SIZE;
+}
+
+/*
+ * Return the page size being used by the MMU to back a VMA. In the majority
+ * of cases, the page size used by the kernel matches the MMU size. On
+ * architectures where it differs, an architecture-specific version of this
+ * function is required.
+ */
+#ifndef vma_mmu_pagesize
+static inline unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
+{
+ return vma_kernel_pagesize(vma);
+}
+#endif
+
#ifdef CONFIG_HUGETLBFS
struct hugetlbfs_sb_info {
long max_inodes; /* inodes allowed */
@@ -394,10 +418,6 @@ static inline unsigned long huge_page_si
return (unsigned long)PAGE_SIZE << h->order;
}
-extern unsigned long vma_kernel_pagesize(struct vm_area_struct *vma);
-
-extern unsigned long vma_mmu_pagesize(struct vm_area_struct *vma);
-
static inline unsigned long huge_page_mask(struct hstate *h)
{
return h->mask;
@@ -532,8 +552,6 @@ struct hstate {};
#define page_hstate(page) NULL
#define huge_page_size(h) PAGE_SIZE
#define huge_page_mask(h) PAGE_MASK
-#define vma_kernel_pagesize(v) PAGE_SIZE
-#define vma_mmu_pagesize(v) PAGE_SIZE
#define huge_page_order(h) 0
#define huge_page_shift(h) PAGE_SHIFT
static inline bool hstate_is_gigantic(struct hstate *h)
diff -puN include/linux/mm.h~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct include/linux/mm.h
--- a/include/linux/mm.h~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct
+++ a/include/linux/mm.h
@@ -383,6 +383,7 @@ struct vm_operations_struct {
int (*huge_fault)(struct vm_fault *vmf, enum page_entry_size pe_size);
void (*map_pages)(struct vm_fault *vmf,
pgoff_t start_pgoff, pgoff_t end_pgoff);
+ unsigned long (*pagesize)(struct vm_area_struct * area);
/* notification that a previously read-only page is about to become
* writable, if an error is returned it will cause a SIGBUS */
diff -puN mm/hugetlb.c~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct mm/hugetlb.c
--- a/mm/hugetlb.c~mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct
+++ a/mm/hugetlb.c
@@ -630,36 +630,6 @@ pgoff_t linear_hugepage_index(struct vm_
EXPORT_SYMBOL_GPL(linear_hugepage_index);
/*
- * Return the size of the pages allocated when backing a VMA. In the majority
- * cases this will be same size as used by the page table entries.
- */
-unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
-{
- struct hstate *hstate;
-
- if (!is_vm_hugetlb_page(vma))
- return PAGE_SIZE;
-
- hstate = hstate_vma(vma);
-
- return 1UL << huge_page_shift(hstate);
-}
-EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
-
-/*
- * Return the page size being used by the MMU to back a VMA. In the majority
- * of cases, the page size used by the kernel matches the MMU size. On
- * architectures where it differs, an architecture-specific version of this
- * function is required.
- */
-#ifndef vma_mmu_pagesize
-unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
-{
- return vma_kernel_pagesize(vma);
-}
-#endif
-
-/*
* Flags for MAP_PRIVATE reservations. These are stored in the bottom
* bits of the reservation map pointer, which are always clear due to
* alignment.
@@ -3142,6 +3112,13 @@ static int hugetlb_vm_op_split(struct vm
return 0;
}
+static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
+{
+ struct hstate *hstate = hstate_vma(vma);
+
+ return 1UL << huge_page_shift(hstate);
+}
+
/*
* We cannot handle pagefaults against hugetlb pages at all. They cause
* handle_mm_fault() to try to instantiate regular-sized pages in the
@@ -3159,6 +3136,7 @@ const struct vm_operations_struct hugetl
.open = hugetlb_vm_op_open,
.close = hugetlb_vm_op_close,
.split = hugetlb_vm_op_split,
+ .pagesize = hugetlb_vm_op_pagesize,
};
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
mm-hugetlbfs-introduce-pagesize-to-vm_operations_struct.patch
device-dax-implement-pagesize-for-smaps-to-report-mmupagesize.patch
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