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Commit 699fa216 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
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mm: fix handling PTE-mapped THPs in page_idle_clear_pte_refs() 

For PTE-mapped THP page_check_address_transhuge() is not adequate: it
cannot find all relevant PTEs, only the first one.i

Let's switch it to page_vma_mapped_walk().

I don't think it's subject for stable@: it's not fatal.

Link: http://lkml.kernel.org/r/20170129173858.45174-5-kirill.shutemov@linux.intel.com


Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8eaedede

mm/page_idle.c

+17 −17
Original line number Diff line number Diff line
@@ -54,26 +54,26 @@ static int page_idle_clear_pte_refs_one(struct page *page, 
					struct vm_area_struct *vma,

					unsigned long addr, void *arg)

{

	struct mm_struct *mm = vma->vm_mm;

	pmd_t *pmd;

	pte_t *pte;

	spinlock_t *ptl;

	struct page_vma_mapped_walk pvmw = {

		.page = page,

		.vma = vma,

		.address = addr,

	};

	bool referenced = false;



	if (!page_check_address_transhuge(page, mm, addr, &pmd, &pte, &ptl))

		return SWAP_AGAIN;



	if (pte) {

		referenced = ptep_clear_young_notify(vma, addr, pte);

		pte_unmap(pte);

	while (page_vma_mapped_walk(&pvmw)) {

		addr = pvmw.address;

		if (pvmw.pte) {

			referenced = ptep_clear_young_notify(vma, addr,

					pvmw.pte);

		} else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {

		referenced = pmdp_clear_young_notify(vma, addr, pmd);

			referenced = pmdp_clear_young_notify(vma, addr,

					pvmw.pmd);

		} else {

			/* unexpected pmd-mapped page? */

			WARN_ON_ONCE(1);

		}



	spin_unlock(ptl);

	}



	if (referenced) {

		clear_page_idle(page);