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Date:   Sat, 28 Mar 2020 03:19:59 +0300
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     Zi Yan <ziy@nvidia.com>
Cc:     akpm@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH] thp: Simplify splitting PMD mapping huge zero page
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 <1437F525-1510-45CD-A67F-13DF525083B4@nvidia.com>
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On Fri, Mar 27, 2020 at 01:23:07PM -0400, Zi Yan wrote:
> On 27 Mar 2020, at 13:03, Kirill A. Shutemov wrote:
> 
> > Splitting PMD mapping huge zero page can be simplified a lot: we can
> > just unmap it and fallback to PTE handling.
> 
> So we will have an extra page fault for the first read to each subpage,
> but nothing changes if the first access to a subpage is a write, right?
> BTW, what is the motivation for this code simplification?

Match what we do for file-THP.

I found a problem with the patch. Ignore it for now.

-- 
 Kirill A. Shutemov