Commit 3340289d authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

mm: report the MMU pagesize in /proc/pid/smaps

The KernelPageSize entry in /proc/pid/smaps is the pagesize used by the
kernel to back a VMA.  This matches the size used by the MMU in the
majority of cases.  However, one counter-example occurs on PPC64 kernels
whereby a kernel using 64K as a base pagesize may still use 4K pages for
the MMU on older processor.  To distinguish, this patch reports
MMUPageSize as the pagesize used by the MMU in /proc/pid/smaps.
Signed-off-by: default avatarMel Gorman <>
Cc: "KOSAKI Motohiro" <>
Cc: Alexey Dobriyan <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 08fba699
......@@ -17,6 +17,12 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep);
* The version of vma_mmu_pagesize() in arch/powerpc/mm/hugetlbpage.c needs
* to override the version in mm/hugetlb.c
#define vma_mmu_pagesize vma_mmu_pagesize
* If the arch doesn't supply something else, assume that hugepage
* size aligned regions are ok without further preparation.
......@@ -512,6 +512,13 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1, 0);
unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
return 1UL << mmu_psize_to_shift(psize);
* Called by asm hashtable.S for doing lazy icache flush
......@@ -397,7 +397,8 @@ static int show_smap(struct seq_file *m, void *v)
"Private_Dirty: %8lu kB\n"
"Referenced: %8lu kB\n"
"Swap: %8lu kB\n"
"KernelPageSize: %8lu kB\n",
"KernelPageSize: %8lu kB\n"
"MMUPageSize: %8lu kB\n",
(vma->vm_end - vma->vm_start) >> 10,
mss.resident >> 10,
(unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
......@@ -407,7 +408,8 @@ static int show_smap(struct seq_file *m, void *v)
mss.private_dirty >> 10,
mss.referenced >> 10,
mss.swap >> 10,
vma_kernel_pagesize(vma) >> 10);
vma_kernel_pagesize(vma) >> 10,
vma_mmu_pagesize(vma) >> 10);
if (m->count < m->size) /* vma is copied successfully */
m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0;
......@@ -235,6 +235,8 @@ static inline unsigned long huge_page_size(struct hstate *h)
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;
......@@ -276,6 +278,7 @@ struct hstate {};
#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 unsigned int pages_per_huge_page(struct hstate *h)
......@@ -235,6 +235,19 @@ unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
return 1UL << (hstate->order + PAGE_SHIFT);
* 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);
* Flags for MAP_PRIVATE reservations. These are stored in the bottom
* bits of the reservation map pointer, which are always clear due to
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