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Message-Id: <1457737157-38573-9-git-send-email-kirill.shutemov@linux.intel.com>
Date: Sat, 12 Mar 2016 01:59:00 +0300
From: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To: Hugh Dickins <hughd@...gle.com>,
Andrea Arcangeli <aarcange@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: Dave Hansen <dave.hansen@...el.com>,
Vlastimil Babka <vbabka@...e.cz>,
Christoph Lameter <cl@...two.org>,
Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
Jerome Marchand <jmarchan@...hat.com>,
Yang Shi <yang.shi@...aro.org>,
Sasha Levin <sasha.levin@...cle.com>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
linux-fsdevel@...r.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCHv4 08/25] thp: support file pages in zap_huge_pmd()
split_huge_pmd() for file mappings (and DAX too) is implemented by just
clearing pmd entry as we can re-fill this area from page cache on pte
level later.
This means we don't need deposit page tables when file THP is mapped.
Therefore we shouldn't try to withdraw a page table on zap_huge_pmd()
file THP PMD.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
mm/huge_memory.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 44468fb7cdbf..c22144e3fe11 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1684,10 +1684,16 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
struct page *page = pmd_page(orig_pmd);
page_remove_rmap(page, true);
VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
- add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
VM_BUG_ON_PAGE(!PageHead(page), page);
- pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd));
- atomic_long_dec(&tlb->mm->nr_ptes);
+ if (PageAnon(page)) {
+ pgtable_t pgtable;
+ pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+ pte_free(tlb->mm, pgtable);
+ atomic_long_dec(&tlb->mm->nr_ptes);
+ add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
+ } else {
+ add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR);
+ }
spin_unlock(ptl);
tlb_remove_page(tlb, page);
}
--
2.7.0
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