linux-kernel - Re: [PATCH] mm/memory_failure: reject unsupported non-folio compound page

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Message-ID: <aYQP1wmHFuiktray@hyeyoo>
Date: Thu, 5 Feb 2026 12:34:47 +0900
From: Harry Yoo <harry.yoo@...cle.com>
To: Zi Yan <ziy@...dia.com>
Cc: David Hildenbrand <david@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
        "Liam R. Howlett" <Liam.Howlett@...cle.com>,
        Vlastimil Babka <vbabka@...e.cz>, Mike Rapoport <rppt@...nel.org>,
        Suren Baghdasaryan <surenb@...gle.com>, Michal Hocko <mhocko@...e.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Naoya Horiguchi <nao.horiguchi@...il.com>,
        "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        Yu Zhao <yuzhao@...gle.com>,
        Baolin Wang <baolin.wang@...ux.alibaba.com>,
        Wei Yang <richard.weiyang@...il.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        是参差 <shicenci@...il.com>
Subject: Re: [PATCH] mm/memory_failure: reject unsupported non-folio compound
 page

On Wed, Feb 04, 2026 at 07:56:03PM -0500, Zi Yan wrote:
> When !CONFIG_TRANSPARENT_HUGEPAGE, a non-folio compound page can appear in
> a userspace mapping via either vm_insert_*() functions or
> vm_operatios_struct->fault(). They are not folios, thus should not be
> considered for folio operations like split. Change memory_failure() and
> soft_offline_page() to reject these non-folio compound pages as
> EOPNOTSUPP.
> 
> Add PageNonFolioCompound() helper function. This function is functionally
> equivalent to folio_test_large() && !folio_test_large_rmappable(), but it
> is supposed to be used on struct page. So open code it instead.
> 
> Fixes: 689b8986776c ("mm/memory-failure: improve large block size folio handling")
> Reported-by: 是参差 <shicenci@...il.com>
> Closes: https://lore.kernel.org/all/PS1PPF7E1D7501F1E4F4441E7ECD056DEADAB98A@PS1PPF7E1D7501F.apcprd02.prod.outlook.com/
> Signed-off-by: Zi Yan <ziy@...dia.com>
> ---

Looks good to me,
Acked-by: Harry Yoo <harry.yoo@...cle.com>

-- 
Cheers,
Harry / Hyeonggon