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Commit 08fba699 authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
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mm: report the pagesize backing a VMA in /proc/pid/smaps 



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: default avatarMel Gorman <mel@csn.ul.ie>
Acked-by: default avatar"KOSAKI Motohiro" <kosaki.motohiro@jp.fujitsu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 238c6d54

fs/proc/task_mmu.c

+4 −2
Original line number Diff line number Diff line
@@ -396,7 +396,8 @@ 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)),
@@ -405,7 +406,8 @@ 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);



	if (m->count < m->size)  /* vma is copied successfully */

		m->version = (vma != get_gate_vma(task)) ? vma->vm_start : 0;

include/linux/hugetlb.h

+3 −0
Original line number Diff line number Diff line
@@ -233,6 +233,8 @@ 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;
@@ -273,6 +275,7 @@ 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)

mm/hugetlb.c

+16 −0
Original line number Diff line number Diff line
@@ -219,6 +219,22 @@ static pgoff_t vma_hugecache_offset(struct hstate *h, 
			(vma->vm_pgoff >> huge_page_order(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);



	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