thp: add option to setup migration entries during PMD split (ba988280) · Commits · 戴 / test

We are going to use migration PTE entries to stabilize page counts. If the page is mapped with PMDs we need to split the PMD and setup migration entries. It's reasonable to combine these operations to avoid double-scanning over the page table. Signed-off-by:

Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by:

Sasha Levin <sasha.levin@oracle.com> Tested-by:

Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by:

Vlastimil Babka <vbabka@suse.cz> Acked-by:

Jerome Marchand <jmarchan@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Steve Capper <steve.capper@linaro.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/huge_memory.c

+14 −8

Original line number	Diff line number	Diff line
		@@ -2695,7 +2695,7 @@ static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
		}

		static void __split_huge_pmd_locked(struct vm_area_struct vma, pmd_t pmd,
		unsigned long haddr)
		unsigned long haddr, bool freeze)
		{
		struct mm_struct *mm = vma->vm_mm;
		struct page *page;
		@@ -2739,12 +2739,18 @@ static void __split_huge_pmd_locked(struct vm_area_struct vma, pmd_t pmd,
		* transferred to avoid any possibility of altering
		* permissions across VMAs.
		*/
		if (freeze) {
		swp_entry_t swp_entry;
		swp_entry = make_migration_entry(page + i, write);
		entry = swp_entry_to_pte(swp_entry);
		} else {
		entry = mk_pte(page + i, vma->vm_page_prot);
		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
		if (!write)
		entry = pte_wrprotect(entry);
		if (!young)
		entry = pte_mkold(entry);
		}
		pte = pte_offset_map(&_pmd, haddr);
		BUG_ON(!pte_none(*pte));
		set_pte_at(mm, haddr, pte, entry);
		@@ -2785,7 +2791,7 @@ void __split_huge_pmd(struct vm_area_struct vma, pmd_t pmd,
		mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE);
		ptl = pmd_lock(mm, pmd);
		if (likely(pmd_trans_huge(*pmd)))
		__split_huge_pmd_locked(vma, pmd, haddr);
		__split_huge_pmd_locked(vma, pmd, haddr, false);
		spin_unlock(ptl);
		mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE);
		}

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