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Date:   Mon, 18 Sep 2023 13:57:04 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Kefeng Wang <wangkefeng.wang@huawei.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, ying.huang@intel.com,
        david@redhat.com, Zi Yan <ziy@nvidia.com>,
        Mike Kravetz <mike.kravetz@oracle.com>, hughd@google.com
Subject: Re: [PATCH 0/6] mm: convert numa balancing functions to use a folio
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References: <20230918103213.4166210-1-wangkefeng.wang@huawei.com>
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On Mon, Sep 18, 2023 at 06:32:07PM +0800, Kefeng Wang wrote:
> The do_numa_pages only handle non-compound page, and only PMD-mapped THP
> is handled in do_huge_pmd_numa_page(), but large, PTE-mapped folio will
> be supported, let's convert more numa balancing functions to use/take a
> folio in preparation for that, no functional change intended for now.
> 
> Kefeng Wang (6):
>   sched/numa, mm: make numa migrate functions to take a folio
>   mm: mempolicy: make mpol_misplaced() to take a folio
>   mm: memory: make numa_migrate_prep() to take a folio
>   mm: memory: use a folio in do_numa_page()
>   mm: memory: add vm_normal_pmd_folio()
>   mm: huge_memory: use a folio in do_huge_pmd_numa_page()

This all seems OK.  It's kind of hard to review though because you change
the same line multiple times.  I think it works out better to go top-down
instead of bottom-up.  That is, start with do_numa_page() and pass
&folio->page to numa_migrate_prep.  Then do vm_normal_pmd_folio() followed
by do_huge_pmd_numa_page().  Fourth would have been numa_migrate_prep(),
etc.  I don't want to ask you to redo the entire series, but for future
patch series.

Also, it's nce to do things like remove the unnecessary 'extern' from
function declarations when you change them from page to folio.  And
please try to stick to 80 columns; I know it's not always easy/possible.