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Date:   Mon, 21 Mar 2022 15:32:53 -0700
From:   Roman Gushchin <roman.gushchin@linux.dev>
To:     Zi Yan <ziy@nvidia.com>
Cc:     Matthew Wilcox <willy@infradead.org>, linux-mm@kvack.org,
        Shuah Khan <shuah@kernel.org>, Yang Shi <shy828301@gmail.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Hugh Dickins <hughd@google.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
        linux-kselftest@vger.kernel.org
Subject: Re: [RFC PATCH 4/5] mm: truncate: split huge page cache page to a
 non-zero order if possible.
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 <20220321142128.2471199-5-zi.yan@sent.com>
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On Mon, Mar 21, 2022 at 10:21:27AM -0400, Zi Yan wrote:
> From: Zi Yan <ziy@nvidia.com>
> 
> To minimize the number of pages after a huge page truncation, we do not
> need to split it all the way down to order-0. The huge page has at most
> three parts, the part before offset, the part to be truncated, the part
> remaining at the end. Find the greatest common power of two multiplier of
> the non-zero values of them as the new order, so we can split the huge
> page to this order and keep the remaining pages as large and as few as
> possible.

Would you mind please to describe the algorithm in more details?

Thanks!