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 <mel@csn.ul.ie>
Cc: "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 08fba699

arch/powerpc/include/asm/hugetlb.h

+6 −0
Original line number Diff line number Diff line
@@ -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.

arch/powerpc/mm/hugetlbpage.c

+7 −0
Original line number Diff line number Diff line
@@ -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

 */

fs/proc/task_mmu.c

+4 −2
Original line number Diff line number Diff line
@@ -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;

include/linux/hugetlb.h

+3 −0
Original line number Diff line number Diff line
@@ -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)

mm/hugetlb.c

+13 −0
Original line number Diff line number Diff line
@@ -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);

}

#endif



/*

 * 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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