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Subject: Re: [PATCHv2 19/28] thp: run vma_adjust_trans_huge() outside
 i_mmap_rwsem
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Hugh Dickins <hughd@google.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>
References: <1455200516-132137-1-git-send-email-kirill.shutemov@linux.intel.com>
 <1455200516-132137-20-git-send-email-kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>, Christoph Lameter <cl@gentwo.org>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        Jerome Marchand <jmarchan@redhat.com>, Yang Shi <yang.shi@linaro.org>,
        Sasha Levin <sasha.levin@oracle.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
From: Dave Hansen <dave.hansen@intel.com>
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Date: Fri, 12 Feb 2016 10:50:02 -0800
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On 02/11/2016 06:21 AM, Kirill A. Shutemov wrote:
> vma_addjust_trans_huge() splits pmd if it's crossing VMA boundary.
> During split we munlock the huge page which requires rmap walk.
> rmap wants to take the lock on its own.

Which lock are you talking about here?