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Commit 16fbdce6 authored by Konstantin Khlebnikov's avatar Konstantin Khlebnikov Committed by Linus Torvalds
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proc/pid/pagemap: correctly report non-present ptes and holes between vmas 



Reset the current pagemap-entry if the current pte isn't present, or if
current vma is over.  Otherwise pagemap reports last entry again and
again.

Non-present pte reporting was broken in commit 092b50ba ("pagemap:
introduce data structure for pagemap entry")

Reporting for holes was broken in commit 5aaabe83 ("pagemap: avoid
splitting thp when reading /proc/pid/pagemap")

Signed-off-by: default avatarKonstantin Khlebnikov <khlebnikov@openvz.org>
Reported-by: default avatarPavel Emelyanov <xemul@parallels.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bc46f937

fs/proc/task_mmu.c

+10 −2
Original line number Diff line number Diff line
@@ -747,6 +747,8 @@ static void pte_to_pagemap_entry(pagemap_entry_t *pme, pte_t pte) 
	else if (pte_present(pte))

		*pme = make_pme(PM_PFRAME(pte_pfn(pte))

				| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);

	else

		*pme = make_pme(PM_NOT_PRESENT);

}



#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -761,6 +763,8 @@ static void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, 
	if (pmd_present(pmd))

		*pme = make_pme(PM_PFRAME(pmd_pfn(pmd) + offset)

				| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);

	else

		*pme = make_pme(PM_NOT_PRESENT);

}

#else

static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme,
@@ -801,8 +805,10 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, 


		/* check to see if we've left 'vma' behind

		 * and need a new, higher one */

		if (vma && (addr >= vma->vm_end))

		if (vma && (addr >= vma->vm_end)) {

			vma = find_vma(walk->mm, addr);

			pme = make_pme(PM_NOT_PRESENT);

		}



		/* check that 'vma' actually covers this address,

		 * and that it isn't a huge page vma */
@@ -830,6 +836,8 @@ static void huge_pte_to_pagemap_entry(pagemap_entry_t *pme, 
	if (pte_present(pte))

		*pme = make_pme(PM_PFRAME(pte_pfn(pte) + offset)

				| PM_PSHIFT(PAGE_SHIFT) | PM_PRESENT);

	else

		*pme = make_pme(PM_NOT_PRESENT);

}



/* This function walks within one hugetlb entry in the single call */
@@ -839,7 +847,7 @@ static int pagemap_hugetlb_range(pte_t *pte, unsigned long hmask, 
{

	struct pagemapread *pm = walk->private;

	int err = 0;

	pagemap_entry_t pme = make_pme(PM_NOT_PRESENT);

	pagemap_entry_t pme;



	for (; addr != end; addr += PAGE_SIZE) {

		int offset = (addr & ~hmask) >> PAGE_SHIFT;