Re: [PATCH] mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check

From	"Kirill A. Shutemov" <kirill@shutemov.name>
Newsgroups	linux.kernel
Subject	Re: [PATCH] mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check
Date	2016-04-03 00:10 +0200
Message-ID	<rjBTX-1Xh-3@gated-at.bofh.it> (permalink)
References	<rjvOx-5Qg-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Sat, Apr 02, 2016 at 06:37:44PM +0300, Konstantin Khlebnikov wrote:
> Khugepaged detects own VMAs by checking vm_file and vm_ops but this
> way it cannot distinguish private /dev/zero mappings from other special
> mappings like /dev/hpet which has no vm_ops and popultes PTEs in mmap.
> 
> This fixes false-positive VM_BUG_ON and prevents installing THP where
> they are not expected.
> 
> Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
> Reported-by: Dmitry Vyukov <dvyukov@google.com>
> Link: http://lkml.kernel.org/r/CACT4Y+ZmuZMV5CjSFOeXviwQdABAgT7T+StKfTqan9YDtgEi5g@mail.gmail.com
> Fixes: 78f11a255749 ("mm: thp: fix /dev/zero MAP_PRIVATE and vm_flags cleanups")
> Cc: stable <stable@vger.kernel.org>

Looks good to me.

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

-- 
 Kirill A. Shutemov

Thread

[PATCH] mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA  check Konstantin Khlebnikov <koct9i@gmail.com> - 2016-04-02 17:40 +0200
  Re: [PATCH] mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual  VMA check "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-04-03 00:10 +0200
  Re: [PATCH] mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual  VMA check Vlastimil Babka <vbabka@suse.cz> - 2016-04-04 14:40 +0200

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