Groups > linux.kernel > #1200261

[PATCH 07/11] thp: Decrement refcount on huge zero page if it is split

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From	Matthew Wilcox <matthew.r.wilcox@intel.com>
Newsgroups	linux.kernel
Subject	[PATCH 07/11] thp: Decrement refcount on huge zero page if it is split
Date	Tue, 04 Aug 2015 22:00:03 +0200
Message-ID	<pTQxt-3Do-45@gated-at.bofh.it> (permalink)
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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>

The DAX code neglected to put the refcount on the huge zero page.
Also we must notify on splits.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
---
 mm/huge_memory.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 5ffdcaa..326d17e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2951,7 +2951,9 @@ again:
 	if (unlikely(!pmd_trans_huge(*pmd)))
 		goto unlock;
 	if (vma_is_dax(vma)) {
-		pmdp_huge_clear_flush(vma, haddr, pmd);
+		pmd_t _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd);
+		if (is_huge_zero_pmd(_pmd))
+			put_huge_zero_page();
 	} else if (is_huge_zero_pmd(*pmd)) {
 		__split_huge_zero_page_pmd(vma, haddr, pmd);
 	} else {
-- 
2.1.4

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Thread

[PATCH 00/11] DAX fixes for 4.3 Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:00 +0200
  [PATCH 10/11] dax: Ensure that zero pages are removed from other processes Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:00 +0200
  [PATCH 09/11] dax: Don't use set_huge_zero_page() Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:00 +0200
  [PATCH 07/11] thp: Decrement refcount on huge zero page if it is split Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:00 +0200
  [PATCH 08/11] thp: Fix zap_huge_pmd() for DAX Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:00 +0200
  [PATCH 01/11] ext4: Use ext4_get_block_write() for DAX Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:10 +0200
  [PATCH 06/11] dax: Fix race between simultaneous faults Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:10 +0200
    Re: [PATCH 06/11] dax: Fix race between simultaneous faults "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-08-05 13:50 +0200
  [PATCH 11/11] dax: Use linear_page_index() Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:10 +0200
  [PATCH 04/11] ext4: Add ext4_get_block_dax() Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:10 +0200
    Re: [PATCH 04/11] ext4: Add ext4_get_block_dax() Dave Chinner <david@fromorbit.com> - 2015-08-05 04:10 +0200
      Re: [PATCH 04/11] ext4: Add ext4_get_block_dax() Matthew Wilcox <willy@linux.intel.com> - 2015-08-05 17:20 +0200
  [PATCH 05/11] ext4: Start transaction before calling into DAX Matthew Wilcox <matthew.r.wilcox@intel.com> - 2015-08-04 22:10 +0200

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