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[PATCH 2/5] mm: skip huge zero page in MADV_FREE

From Minchan Kim <minchan@kernel.org>
Newsgroups linux.kernel
Subject [PATCH 2/5] mm: skip huge zero page in MADV_FREE
Date 2015-10-19 08:30 +0200
Message-ID <qlc7f-4wB-15@gated-at.bofh.it> (permalink)
References <qlc7f-4wB-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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It is pointless to mark huge zero page as freeable.
Let's skip it.

Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 mm/huge_memory.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f1de4ce583a6..269ed99493f0 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1542,6 +1542,9 @@ int madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		struct page *page;
 		pmd_t orig_pmd;
 
+		if (is_huge_zero_pmd(*pmd))
+			goto out;
+
 		orig_pmd = pmdp_huge_get_and_clear(mm, addr, pmd);
 
 		/* No hugepage in swapcache */
@@ -1553,6 +1556,7 @@ int madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 
 		set_pmd_at(mm, addr, pmd, orig_pmd);
 		tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
+out:
 		spin_unlock(ptl);
 		ret = 0;
 	}
-- 
1.9.1

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Thread

[PATCH 0/5] MADV_FREE refactoring and fix KSM page Minchan Kim <minchan@kernel.org> - 2015-10-19 08:30 +0200
  [PATCH 2/5] mm: skip huge zero page in MADV_FREE Minchan Kim <minchan@kernel.org> - 2015-10-19 08:30 +0200
  [PATCH 1/5] mm: MADV_FREE trivial clean up Minchan Kim <minchan@kernel.org> - 2015-10-19 08:30 +0200
  [PATCH 5/5] mm: mark stable page dirty in KSM Minchan Kim <minchan@kernel.org> - 2015-10-19 08:30 +0200
    Re: [PATCH 5/5] mm: mark stable page dirty in KSM Hugh Dickins <hughd@google.com> - 2015-10-27 03:30 +0100
      Re: [PATCH 5/5] mm: mark stable page dirty in KSM Minchan Kim <minchan@kernel.org> - 2015-10-27 08:00 +0100
  [PATCH 3/5] mm: clear PG_dirty to mark page freeable Minchan Kim <minchan@kernel.org> - 2015-10-19 08:30 +0200
    Re: [PATCH 3/5] mm: clear PG_dirty to mark page freeable Hugh Dickins <hughd@google.com> - 2015-10-27 02:30 +0100
      Re: [PATCH 3/5] mm: clear PG_dirty to mark page freeable Minchan Kim <minchan@kernel.org> - 2015-10-27 08:00 +0100
  [PATCH 4/5] mm: simplify reclaim path for MADV_FREE Minchan Kim <minchan@kernel.org> - 2015-10-19 08:40 +0200
    Re: [PATCH 4/5] mm: simplify reclaim path for MADV_FREE Hugh Dickins <hughd@google.com> - 2015-10-27 03:10 +0100
      Re: [PATCH 4/5] mm: simplify reclaim path for MADV_FREE yalin wang <yalin.wang2010@gmail.com> - 2015-10-27 04:50 +0100
        Re: [PATCH 4/5] mm: simplify reclaim path for MADV_FREE Minchan Kim <minchan@kernel.org> - 2015-10-27 08:10 +0100
          Re: [PATCH 4/5] mm: simplify reclaim path for MADV_FREE yalin wang <yalin.wang2010@gmail.com> - 2015-10-27 08:40 +0100
            Re: [PATCH 4/5] mm: simplify reclaim path for MADV_FREE Minchan Kim <minchan@kernel.org> - 2015-10-27 09:20 +0100
              Re: [PATCH 4/5] mm: simplify reclaim path for MADV_FREE yalin wang <yalin.wang2010@gmail.com> - 2015-10-27 10:00 +0100
                Re: [PATCH 4/5] mm: simplify reclaim path for MADV_FREE yalin wang <yalin.wang2010@gmail.com> - 2015-10-28 05:10 +0100
      Re: [PATCH 4/5] mm: simplify reclaim path for MADV_FREE Minchan Kim <minchan@kernel.org> - 2015-10-27 08:00 +0100
  Re: [PATCH 0/5] MADV_FREE refactoring and fix KSM page Minchan Kim <minchan@kernel.org> - 2015-10-19 12:00 +0200
    Re: [PATCH 0/5] MADV_FREE refactoring and fix KSM page Minchan Kim <minchan@kernel.org> - 2015-10-20 09:30 +0200
    Re: [PATCH 0/5] MADV_FREE refactoring and fix KSM page Minchan Kim <minchan@kernel.org> - 2015-10-20 09:30 +0200
      Re: [PATCH 0/5] MADV_FREE refactoring and fix KSM page Andrew Morton <akpm@linux-foundation.org> - 2015-10-20 23:40 +0200
        Re: [PATCH 0/5] MADV_FREE refactoring and fix KSM page "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-10-21 00:50 +0200
          Re: [PATCH 0/5] MADV_FREE refactoring and fix KSM page Minchan Kim <minchan@kernel.org> - 2015-10-21 07:20 +0200
            Re: [PATCH 0/5] MADV_FREE refactoring and fix KSM page "Kirill A. Shutemov" <kirill@shutemov.name> - 2015-10-21 10:00 +0200

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