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From: Zi Yan <ziy@nvidia.com>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
 John Hubbard <jhubbard@nvidia.com>, Matthew Wilcox <willy@infradead.org>,
 Andrew Morton <akpm@linux-foundation.org>,
 Baolin Wang <baolin.wang@linux.alibaba.com>
Subject: Re: [PATCH v1] mm/huge_memory: improve
 split_huge_page_to_list_to_order() return value documentation
Date: Mon, 22 Apr 2024 10:21:26 -0400
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On 18 Apr 2024, at 11:18, David Hildenbrand wrote:

> The documentation is wrong and relying on it almost resulted in BUGs
> in new callers: we return -EAGAIN on unexpected folio references, not
> -EBUSY.

+Baolin

The code was changed at the commit fd4a7ac32918 ("mm: migrate: try again
if THP split is failed due to page refcnt") without changing the comment.

>
> Let's fix that and also document which other return values we can
> currently see and why they could happen.
>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  mm/huge_memory.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)

The changes look good to me. Thanks. Reviewed-by: Zi Yan <ziy@nvidia.com>

--
Best Regards,
Yan, Zi

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