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Re: [PATCH 2/2] mm/thp/pagecache/collapse: Free the pte page table on collapse for thp page cache.

From "Kirill A. Shutemov" <kirill@shutemov.name>
Newsgroups linux.kernel
Subject Re: [PATCH 2/2] mm/thp/pagecache/collapse: Free the pte page table on collapse for thp page cache.
Date 2016-12-12 22:10 +0100
Message-ID <sNG1c-R8-41@gated-at.bofh.it> (permalink)
References <sNBNU-6Du-39@gated-at.bofh.it> <sNBNU-6Du-37@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Mon, Dec 12, 2016 at 10:04:28PM +0530, Aneesh Kumar K.V wrote:
> With THP page cache, when trying to build a huge page from regular pte pages,
> we just clear the pmd entry. We will take another fault and at that point we
> will find the huge page in the radix tree, thereby using the huge page to
> complete the page fault
> 
> The second fault path will allocate the needed pgtable_t page for archs like
> ppc64. So no need to deposit the same in collapse path. Depositing them in
> the collapse path resulting in a pgtable_t memory leak also giving errors like
> "[ 2362.021762] BUG: non-zero nr_ptes on freeing mm: 3"
> 
> Fixes:"mm: THP page cache support for ppc64"
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

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

-- 
 Kirill A. Shutemov

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Thread

[PATCH 1/2] mm/thp/pagecache: Only withdraw page table after a successful deposit "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2016-12-12 17:40 +0100
  [PATCH 2/2] mm/thp/pagecache/collapse: Free the pte page table on collapse for thp page cache. "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> - 2016-12-12 17:40 +0100
    Re: [PATCH 2/2] mm/thp/pagecache/collapse: Free the pte page table  on collapse for thp page cache. "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-12-12 22:10 +0100
  Re: [PATCH 1/2] mm/thp/pagecache: Only withdraw page table after a  successful deposit "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-12-12 22:10 +0100

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