[PATCH 0/3] Report the size of pages backing VMAs in /proc V2

[PATCH 0/3] Report the size of pages backing VMAs in /proc V2

[Mel Gorman]

The following three patches add support for printing the size of pages to
back VMAs in maps and smaps. This can be used by a user to verify that a
hugepage-aware application is using the expected page sizes.

The first patch prints the size of page used by the kernel when allocating
pages for a VMA in /proc/pid/smaps and should not be considered too contentious
as it is highly unlikely to break any parsers. The second patch reports on
the size of page used by the MMU as it can differ - for example on POWER
using 64K as a base pagesize on older processors. The final patch reports
the size of page used by hugetlbfs regions in /proc/pid/maps. There is a
possibility that the final patch will break parsers but they are arguably
already broken. More details are in the patches themselves.

Changelog since V1
  o Fix build failure on !CONFIG_HUGETLB_PAGE
  o Uninline helper functions
  o Distinguish between base pagesize and MMU pagesize

 arch/powerpc/include/asm/hugetlb.h |    6 ++++++
 arch/powerpc/mm/hugetlbpage.c      |    7 +++++++
 fs/proc/task_mmu.c                 |   32 ++++++++++++++++++++++++--------
 include/linux/hugetlb.h            |    6 ++++++
 mm/hugetlb.c                       |   30 ++++++++++++++++++++++++++++++
 5 files changed, 73 insertions(+), 8 deletions(-)

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[PATCH 1/3] Report the pagesize backing a VMA in /proc/pid/smaps

[Mel Gorman]

It is useful to verify a hugepage-aware application is using the expected
pagesizes for its memory regions. This patch creates an entry called
KernelPageSize in /proc/pid/smaps that is the size of page used by the kernel
to back a VMA. The entry is not called PageSize as it is possible the MMU
uses a different size. This extension should not break any sensible parser
that skips lines containing unrecognised information.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
---
 fs/proc/task_mmu.c      |    6 ++++--
 include/linux/hugetlb.h |    3 +++
 mm/hugetlb.c            |   17 +++++++++++++++++
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 73d1891..08b453f 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -394,7 +394,8 @@ static int show_smap(struct seq_file *m, void *v)
 		   "Private_Clean:  %8lu kB\n"
 		   "Private_Dirty:  %8lu kB\n"
 		   "Referenced:     %8lu kB\n"
-		   "Swap:           %8lu kB\n",
+		   "Swap:           %8lu kB\n"
+		   "KernelPageSize: %8lu kB\n",
 		   (vma->vm_end - vma->vm_start) >> 10,
 		   mss.resident >> 10,
 		   (unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
@@ -403,7 +404,8 @@ static int show_smap(struct seq_file *m, void *v)
 		   mss.private_clean >> 10,
 		   mss.private_dirty >> 10,
 		   mss.referenced >> 10,
-		   mss.swap >> 10);
+		   mss.swap >> 10,
+		   vma_kernel_pagesize(vma) >> 10);
 
 	return ret;
 }
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 32e0ef0..ace04a7 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -231,6 +231,8 @@ static inline unsigned long huge_page_size(struct hstate *h)
 	return (unsigned long)PAGE_SIZE << h->order;
 }
 
+extern unsigned long vma_kernel_pagesize(struct vm_area_struct *vma);
+
 static inline unsigned long huge_page_mask(struct hstate *h)
 {
 	return h->mask;
@@ -271,6 +273,7 @@ struct hstate {};
 #define hstate_inode(i) NULL
 #define huge_page_size(h) PAGE_SIZE
 #define huge_page_mask(h) PAGE_MASK
+#define vma_kernel_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)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 67a7119..9c7ff96 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -219,6 +219,23 @@ static pgoff_t vma_hugecache_offset(struct hstate *h,
 }
 
 /*
+ * 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);
+	VM_BUG_ON(!hstate);
+
+	return 1UL << (hstate->order + PAGE_SHIFT);
+}
+
+/*
  * Flags for MAP_PRIVATE reservations.  These are stored in the bottom
  * bits of the reservation map pointer, which are always clear due to
  * alignment.
-- 
1.5.6.5

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[PATCH 2/3] Report the MMU pagesize in /proc/pid/smaps

[Mel Gorman]

The KernelPageSize entry in /proc/pid/maps 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: Mel Gorman <mel@csn.ul.ie>
---
 arch/powerpc/include/asm/hugetlb.h |    6 ++++++
 arch/powerpc/mm/hugetlbpage.c      |    7 +++++++
 fs/proc/task_mmu.c                 |    6 ++++--
 include/linux/hugetlb.h            |    3 +++
 mm/hugetlb.c                       |   13 +++++++++++++
 5 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/hugetlb.h b/arch/powerpc/include/asm/hugetlb.h
index 26f0d0a..2655146 100644
--- a/arch/powerpc/include/asm/hugetlb.h
+++ b/arch/powerpc/include/asm/hugetlb.h
@@ -18,6 +18,12 @@ 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.
  */
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index f1c2d55..c44d01e 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -503,6 +503,13 @@ 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
  */
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 08b453f..ee1f4eb 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -395,7 +395,8 @@ 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)),
@@ -405,7 +406,8 @@ 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);
 
 	return ret;
 }
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index ace04a7..5056021 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -233,6 +233,8 @@ 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;
@@ -274,6 +276,7 @@ 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)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9c7ff96..91a7c2d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -236,6 +236,19 @@ unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
 }
 
 /*
+ * 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.
-- 
1.5.6.5

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[PATCH 3/3] Report the pagesize backing a VMA in /proc/pid/maps

[Mel Gorman]

This patch adds a new field for hugepage-backed memory regions to show the
pagesize in /proc/pid/maps.  While the information is available in smaps,
maps is more human-readable and does not incur the cost of calculating Pss. An
example of a /proc/self/maps output for an application using hugepages with
this patch applied is;

08048000-0804c000 r-xp 00000000 03:01 49135      /bin/cat
0804c000-0804d000 rw-p 00003000 03:01 49135      /bin/cat
08400000-08800000 rw-p 00000000 00:10 4055       /mnt/libhugetlbfs.tmp.QzPPTJ (deleted) (hpagesize=4096kB)
b7daa000-b7dab000 rw-p b7daa000 00:00 0
b7dab000-b7ed2000 r-xp 00000000 03:01 116846     /lib/tls/i686/cmov/libc-2.3.6.so
b7ed2000-b7ed7000 r--p 00127000 03:01 116846     /lib/tls/i686/cmov/libc-2.3.6.so
b7ed7000-b7ed9000 rw-p 0012c000 03:01 116846     /lib/tls/i686/cmov/libc-2.3.6.so
b7ed9000-b7edd000 rw-p b7ed9000 00:00 0
b7ee1000-b7ee8000 r-xp 00000000 03:01 49262      /root/libhugetlbfs-git/obj32/libhugetlbfs.so
b7ee8000-b7ee9000 rw-p 00006000 03:01 49262      /root/libhugetlbfs-git/obj32/libhugetlbfs.so
b7ee9000-b7eed000 rw-p b7ee9000 00:00 0
b7eed000-b7f02000 r-xp 00000000 03:01 119345     /lib/ld-2.3.6.so
b7f02000-b7f04000 rw-p 00014000 03:01 119345     /lib/ld-2.3.6.so
bf8ef000-bf903000 rwxp bffeb000 00:00 0          [stack]
bf903000-bf904000 rw-p bffff000 00:00 0
ffffe000-fffff000 r-xp 00000000 00:00 0          [vdso]

To be predictable for parsers, the patch adds the notion of reporting on VMA
attributes by appending one or more fields that look like "(attribute)". This
already happens when a file is deleted and the user sees (deleted) after the
filename. The expectation is that existing parsers will not break as those
that read the filename should be reading forward after the inode number
and stopping when it sees something that is not part of the filename.
Parsers that assume everything after / is a filename will get confused by
(hpagesize=XkB) but are already broken due to (deleted).

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
---
 fs/proc/task_mmu.c |   24 ++++++++++++++++++------
 1 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ee1f4eb..bb90326 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -198,7 +198,7 @@ static int do_maps_open(struct inode *inode, struct file *file,
 	return ret;
 }
 
-static int show_map(struct seq_file *m, void *v)
+static int __show_map(struct seq_file *m, void *v, int showattributes)
 {
 	struct proc_maps_private *priv = m->private;
 	struct task_struct *task = priv->task;
@@ -233,8 +233,8 @@ static int show_map(struct seq_file *m, void *v)
 	 * Print the dentry name for named mappings, and a
 	 * special [heap] marker for the heap:
 	 */
+	pad_len_spaces(m, len);
 	if (file) {
-		pad_len_spaces(m, len);
 		seq_path(m, &file->f_path, "\n");
 	} else {
 		const char *name = arch_vma_name(vma);
@@ -251,11 +251,18 @@ static int show_map(struct seq_file *m, void *v)
 				name = "[vdso]";
 			}
 		}
-		if (name) {
-			pad_len_spaces(m, len);
+		if (name)
 			seq_puts(m, name);
-		}
 	}
+
+	/*
+	 * Print additional attributes of the VMA of interest
+	 * - hugepage size if hugepage-backed
+	 */
+	if (showattributes && vma->vm_flags & VM_HUGETLB)
+		seq_printf(m, " (hpagesize=%lukB)",
+			vma_kernel_pagesize(vma) >> 10);
+
 	seq_putc(m, '\n');
 
 	if (m->count < m->size)  /* vma is copied successfully */
@@ -263,6 +270,11 @@ static int show_map(struct seq_file *m, void *v)
 	return 0;
 }
 
+static int show_map(struct seq_file *m, void *v)
+{
+	return __show_map(m, v, 1);
+}
+
 static const struct seq_operations proc_pid_maps_op = {
 	.start	= m_start,
 	.next	= m_next,
@@ -381,7 +393,7 @@ static int show_smap(struct seq_file *m, void *v)
 	if (vma->vm_mm && !is_vm_hugetlb_page(vma))
 		walk_page_range(vma->vm_start, vma->vm_end, &smaps_walk);
 
-	ret = show_map(m, v);
+	ret = __show_map(m, v, 0);
 	if (ret)
 		return ret;
 
-- 
1.5.6.5

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Re: [PATCH 1/3] Report the pagesize backing a VMA in /proc/pid/smaps

[KOSAKI Motohiro]

> It is useful to verify a hugepage-aware application is using the expected
> pagesizes for its memory regions. This patch creates an entry called
> KernelPageSize in /proc/pid/smaps that is the size of page used by the kernel
> to back a VMA. The entry is not called PageSize as it is possible the MMU
> uses a different size. This extension should not break any sensible parser
> that skips lines containing unrecognised information.
> 
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>

looks good to me.
and, I tested this patch on x86_64 mmotm 0923 and it works well.


Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>



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Re: [PATCH 3/3] Report the pagesize backing a VMA in /proc/pid/maps

[KOSAKI Motohiro]

> This patch adds a new field for hugepage-backed memory regions to show the
> pagesize in /proc/pid/maps.  While the information is available in smaps,
> maps is more human-readable and does not incur the cost of calculating Pss. An
> example of a /proc/self/maps output for an application using hugepages with
> this patch applied is;
> 
> 08048000-0804c000 r-xp 00000000 03:01 49135      /bin/cat
> 0804c000-0804d000 rw-p 00003000 03:01 49135      /bin/cat
> 08400000-08800000 rw-p 00000000 00:10 4055       /mnt/libhugetlbfs.tmp.QzPPTJ (deleted) (hpagesize=4096kB)
> b7daa000-b7dab000 rw-p b7daa000 00:00 0
> b7dab000-b7ed2000 r-xp 00000000 03:01 116846     /lib/tls/i686/cmov/libc-2.3.6.so
> b7ed2000-b7ed7000 r--p 00127000 03:01 116846     /lib/tls/i686/cmov/libc-2.3.6.so
> b7ed7000-b7ed9000 rw-p 0012c000 03:01 116846     /lib/tls/i686/cmov/libc-2.3.6.so
> b7ed9000-b7edd000 rw-p b7ed9000 00:00 0
> b7ee1000-b7ee8000 r-xp 00000000 03:01 49262      /root/libhugetlbfs-git/obj32/libhugetlbfs.so
> b7ee8000-b7ee9000 rw-p 00006000 03:01 49262      /root/libhugetlbfs-git/obj32/libhugetlbfs.so
> b7ee9000-b7eed000 rw-p b7ee9000 00:00 0
> b7eed000-b7f02000 r-xp 00000000 03:01 119345     /lib/ld-2.3.6.so
> b7f02000-b7f04000 rw-p 00014000 03:01 119345     /lib/ld-2.3.6.so
> bf8ef000-bf903000 rwxp bffeb000 00:00 0          [stack]
> bf903000-bf904000 rw-p bffff000 00:00 0
> ffffe000-fffff000 r-xp 00000000 00:00 0          [vdso]
> 
> To be predictable for parsers, the patch adds the notion of reporting on VMA
> attributes by appending one or more fields that look like "(attribute)". This
> already happens when a file is deleted and the user sees (deleted) after the
> filename. The expectation is that existing parsers will not break as those
> that read the filename should be reading forward after the inode number
> and stopping when it sees something that is not part of the filename.
> Parsers that assume everything after / is a filename will get confused by
> (hpagesize=XkB) but are already broken due to (deleted).
> 
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>

looks good to me.

However, this patch can't build on x86_64 mmotm 0923 because it conflict
against fix-vma-display-mismatch-between-proc-pid-mapssmaps.patch
(by Joe Korty <joe.korty@ccur.com>).

instead, I tested following rebased version and I confirmed it works well.



===============================================================
From: Mel Gorman <mel@csn.ul.ie>

This patch adds a new field for hugepage-backed memory regions to show the
pagesize in /proc/pid/maps.  While the information is available in smaps,
maps is more human-readable and does not incur the cost of calculating Pss. An
example of a /proc/self/maps output for an application using hugepages with
this patch applied is;

08048000-0804c000 r-xp 00000000 03:01 49135      /bin/cat
0804c000-0804d000 rw-p 00003000 03:01 49135      /bin/cat
08400000-08800000 rw-p 00000000 00:10 4055       /mnt/libhugetlbfs.tmp.QzPPTJ (deleted) (hpagesize=4096kB)
b7daa000-b7dab000 rw-p b7daa000 00:00 0
b7dab000-b7ed2000 r-xp 00000000 03:01 116846     /lib/tls/i686/cmov/libc-2.3.6.so
b7ed2000-b7ed7000 r--p 00127000 03:01 116846     /lib/tls/i686/cmov/libc-2.3.6.so
b7ed7000-b7ed9000 rw-p 0012c000 03:01 116846     /lib/tls/i686/cmov/libc-2.3.6.so
b7ed9000-b7edd000 rw-p b7ed9000 00:00 0
b7ee1000-b7ee8000 r-xp 00000000 03:01 49262      /root/libhugetlbfs-git/obj32/libhugetlbfs.so
b7ee8000-b7ee9000 rw-p 00006000 03:01 49262      /root/libhugetlbfs-git/obj32/libhugetlbfs.so
b7ee9000-b7eed000 rw-p b7ee9000 00:00 0
b7eed000-b7f02000 r-xp 00000000 03:01 119345     /lib/ld-2.3.6.so
b7f02000-b7f04000 rw-p 00014000 03:01 119345     /lib/ld-2.3.6.so
bf8ef000-bf903000 rwxp bffeb000 00:00 0          [stack]
bf903000-bf904000 rw-p bffff000 00:00 0
ffffe000-fffff000 r-xp 00000000 00:00 0          [vdso]

To be predictable for parsers, the patch adds the notion of reporting on VMA
attributes by appending one or more fields that look like "(attribute)". This
already happens when a file is deleted and the user sees (deleted) after the
filename. The expectation is that existing parsers will not break as those
that read the filename should be reading forward after the inode number
and stopping when it sees something that is not part of the filename.
Parsers that assume everything after / is a filename will get confused by
(hpagesize=XkB) but are already broken due to (deleted).

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
 fs/proc/task_mmu.c |   29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

Index: b/fs/proc/task_mmu.c
===================================================================
--- a/fs/proc/task_mmu.c	2008-09-25 21:51:39.000000000 +0900
+++ b/fs/proc/task_mmu.c	2008-09-25 22:30:48.000000000 +0900
@@ -198,7 +198,8 @@ static int do_maps_open(struct inode *in
 	return ret;
 }
 
-static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
+static void show_map_vma(struct seq_file *m, struct vm_area_struct *vma,
+			 int showattributes)
 {
 	struct mm_struct *mm = vma->vm_mm;
 	struct file *file = vma->vm_file;
@@ -227,8 +228,8 @@ static void show_map_vma(struct seq_file
 	 * Print the dentry name for named mappings, and a
 	 * special [heap] marker for the heap:
 	 */
+	pad_len_spaces(m, len);
 	if (file) {
-		pad_len_spaces(m, len);
 		seq_path(m, &file->f_path, "\n");
 	} else {
 		const char *name = arch_vma_name(vma);
@@ -245,15 +246,22 @@ static void show_map_vma(struct seq_file
 				name = "[vdso]";
 			}
 		}
-		if (name) {
-			pad_len_spaces(m, len);
+		if (name)
 			seq_puts(m, name);
-		}
 	}
+
+	/*
+	 * Print additional attributes of the VMA of interest
+	 * - hugepage size if hugepage-backed
+	 */
+	if (showattributes && vma->vm_flags & VM_HUGETLB)
+		seq_printf(m, " (hpagesize=%lukB)",
+			vma_kernel_pagesize(vma) >> 10);
+
 	seq_putc(m, '\n');
 }
 
-static int show_map(struct seq_file *m, void *v)
+static int __show_map(struct seq_file *m, void *v, int showattributes)
 {
 	struct vm_area_struct *vma = v;
 	struct proc_maps_private *priv = m->private;
@@ -262,13 +270,18 @@ static int show_map(struct seq_file *m, 
 	if (maps_protect && !ptrace_may_access(task, PTRACE_MODE_READ))
 		return -EACCES;
 
-	show_map_vma(m, vma);
+	show_map_vma(m, vma, showattributes);
 
 	if (m->count < m->size)  /* vma is copied successfully */
 		m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0;
 	return 0;
 }
 
+static int show_map(struct seq_file *m, void *v)
+{
+	return __show_map(m, v, 1);
+}
+
 static const struct seq_operations proc_pid_maps_op = {
 	.start	= m_start,
 	.next	= m_next,
@@ -391,7 +404,7 @@ static int show_smap(struct seq_file *m,
 	if (maps_protect && !ptrace_may_access(task, PTRACE_MODE_READ))
 		return -EACCES;
 
-	show_map_vma(m, vma);
+	show_map_vma(m, vma, 0);
 
 	seq_printf(m,
 		   "Size:           %8lu kB\n"


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