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Date:   Fri, 30 Oct 2020 18:12:46 +0000
From:   Matthew Wilcox <willy@infradead.org>
To:     Zi Yan <ziy@nvidia.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        Yang Shi <shy828301@gmail.com>, Michal Hocko <mhocko@suse.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Rik van Riel <riel@surriel.com>,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH v2 1/2] mm/compaction: count pages and stop correctly
 during page isolation.
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References: <20201030155716.3614401-1-zi.yan@sent.com>
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On Fri, Oct 30, 2020 at 11:57:15AM -0400, Zi Yan wrote:
> In isolate_migratepages_block, when cc->alloc_contig is true, we are
> able to isolate compound pages, nr_migratepages and nr_isolated did not
> count compound pages correctly, causing us to isolate more pages than we
> thought. Use thp_nr_pages to count pages. Otherwise, we might be trapped
               ^^^^^^^^^^^^
Maybe replace that sentence with "Count compound pages as the number of
base pages they contain"?