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Date:   Mon, 7 Sep 2020 15:22:28 +0300
From:   "Kirill A. Shutemov" <kirill@shutemov.name>
To:     Zi Yan <ziy@nvidia.com>
Cc:     linux-mm@kvack.org, Roman Gushchin <guro@fb.com>,
        Rik van Riel <riel@surriel.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Matthew Wilcox <willy@infradead.org>,
        Shakeel Butt <shakeelb@google.com>,
        Yang Shi <yang.shi@linux.alibaba.com>,
        David Nellans <dnellans@nvidia.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 01/16] mm: add pagechain container for storing
 multiple pages.
Message-ID: <20200907122228.4zlyfysdul3s62me@box>
References: <20200902180628.4052244-1-zi.yan@sent.com>
 <20200902180628.4052244-2-zi.yan@sent.com>
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On Wed, Sep 02, 2020 at 02:06:13PM -0400, Zi Yan wrote:
> From: Zi Yan <ziy@nvidia.com>
> 
> When depositing page table pages for 1GB THPs, we need 512 PTE pages +
> 1 PMD page. Instead of counting and depositing 513 pages, we can use the
> PMD page as a leader page and chain the rest 512 PTE pages with ->lru.
> This, however, prevents us depositing PMD pages with ->lru, which is
> currently used by depositing PTE pages for 2MB THPs. So add a new
> pagechain container for PMD pages.
> 
> Signed-off-by: Zi Yan <ziy@nvidia.com>

Just deposit it to a linked list in the mm_struct as we do for PMD if
split ptl disabled.

-- 
 Kirill A. Shutemov