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Subject: Re: [v2 PATCH] mm: vmscan: correct nr_reclaimed for THP
To:     Johannes Weiner <hannes@cmpxchg.org>
Cc:     Michal Hocko <mhocko@kernel.org>, Yang Shi <shy828301@gmail.com>,
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> [ check_move_unevictable_pages() seems weird. It gets a pagevec from
>    find_get_entries(), which, if I understand the THP page cache code
>    correctly, might contain the same compound page over and over. It'll
>    be !unevictable after the first iteration, so will only run once. So
>    it produces incorrect numbers now, but it is probably best to ignore
>    it until we figure out THP cache. Maybe add an XXX comment. ]

The commit 5fd4ca2d84b2 ("mm: page cache: store only head pages in 
i_pages") changed how THP is stored in page cache, but 
find_get_entries() would return base page by calling find_subpage(), so 
check_move_unevictable_pages() should just returns the number of base pages.