From: Pratyush Yadav <pratyush@kernel.org>
To: DaeMyung Kang <charsyam@gmail.com>
Cc: pasha.tatashin@soleen.com, rppt@kernel.org,
akpm@linux-foundation.org, pratyush@kernel.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: memfd_luo: account restored large folios correctly
Date: Tue, 14 Apr 2026 10:48:32 +0000 [thread overview]
Message-ID: <2vxzik9t95rz.fsf@kernel.org> (raw)
In-Reply-To: <20260413165053.164338-1-charsyam@gmail.com> (DaeMyung Kang's message of "Tue, 14 Apr 2026 01:50:53 +0900")
Hi DaeMyung,
On Tue, Apr 14 2026, DaeMyung Kang wrote:
> memfd_luo_retrieve_folios() always passes 1 to
> shmem_inode_acct_blocks() and shmem_recalc_inode(), even when the
> restored folio spans multiple pages.
>
> That mismatches the normal shmem path: shmem_add_to_page_cache()
> accounts the folio in mapping->nrpages using folio_nr_pages(folio),
> and shmem_alloc_and_add_folio() passes the same page count to
> shmem_inode_acct_blocks() and shmem_recalc_inode().
>
> As a result, restored large folios are under-accounted in shmem inode
> and block accounting.
>
> Use folio_nr_pages(folio) here as well.
>
> Fixes: b3749f174d68 ("mm: memfd_luo: allow preserving memfd")
> Signed-off-by: DaeMyung Kang <charsyam@gmail.com>
Thanks for the patch. This bug is already fixed by this patch [0].
[0] https://lore.kernel.org/linux-mm/20260326084727.118437-2-duanchenghao@kylinos.cn/
[...]
--
Regards,
Pratyush Yadav
prev parent reply other threads:[~2026-04-14 10:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-13 16:50 DaeMyung Kang
2026-04-14 10:48 ` Pratyush Yadav [this message]
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