linux-kernel - Re: [PATCH v2 1/2] mm/compaction: count pages and stop correctly during page isolation.

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Date:   Fri, 30 Oct 2020 14:15:09 -0400
From:   Zi Yan <ziy@...dia.com>
To:     Matthew Wilcox <willy@...radead.org>
CC:     Andrew Morton <akpm@...ux-foundation.org>, <linux-mm@...ck.org>,
        Yang Shi <shy828301@...il.com>, Michal Hocko <mhocko@...e.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Rik van Riel <riel@...riel.com>,
        <linux-kernel@...r.kernel.org>, <stable@...r.kernel.org>
Subject: Re: [PATCH v2 1/2] mm/compaction: count pages and stop correctly
 during page isolation.

On 30 Oct 2020, at 14:12, Matthew Wilcox wrote:

> 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"?

Sure. And compound_nr is used instead of thp_nr_pages in fact.

OK. V3 is coming.

—
Best Regards,
Yan Zi

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