From: "David Hildenbrand (Arm)" <david@kernel.org>
To: "Lorenzo Stoakes (Oracle)" <ljs@kernel.org>, Zi Yan <ziy@nvidia.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
Song Liu <songliubraving@fb.com>, Chris Mason <clm@fb.com>,
David Sterba <dsterba@suse.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Nico Pache <npache@redhat.com>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Shuah Khan <shuah@kernel.org>,
linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v1 03/10] mm: fs: remove filemap_nr_thps*() functions and their users
Date: Fri, 27 Mar 2026 14:58:12 +0100 [thread overview]
Message-ID: <b098fce7-be16-479e-b9a4-36f0ad71d242@kernel.org> (raw)
In-Reply-To: <aaea8ce1-eac6-49d6-8c85-7361977b9a9f@lucifer.local>
On 3/27/26 13:23, Lorenzo Stoakes (Oracle) wrote:
> On Thu, Mar 26, 2026 at 09:42:48PM -0400, Zi Yan wrote:
>> They are used by READ_ONLY_THP_FOR_FS to handle writes to FSes without
>> large folio support, so that read-only THPs created in these FSes are not
>> seen by the FSes when the underlying fd becomes writable. Now read-only PMD
>> THPs only appear in a FS with large folio support and the supported orders
>> include PMD_ORDRE.
>
> Typo: PMD_ORDRE -> PMD_ORDER
>
>>
>> Signed-off-by: Zi Yan <ziy@nvidia.com>
>
> This looks obviously-correct since this stuff wouldn't have been invoked for
> large folio file systems before + they already had to handle it separately, and
> this function is only tied to CONFIG_READ_ONLY_THP_FOR_FS (+ a quick grep
> suggests you didn't miss anything), so:
There could now be a race between collapsing and the file getting opened
r/w.
Are we sure that all code can really deal with that?
IOW, "they already had to handle it separately" -- is that true?
khugepaged would have never collapse in writable files, so I wonder if
all code paths are prepared for that.
--
Cheers,
David
next prev parent reply other threads:[~2026-03-27 13:58 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-27 1:42 [PATCH v1 00/10] Remove READ_ONLY_THP_FOR_FS Kconfig Zi Yan
2026-03-27 1:42 ` [PATCH v1 01/10] mm: remove READ_ONLY_THP_FOR_FS Kconfig option Zi Yan
2026-03-27 11:45 ` Lorenzo Stoakes (Oracle)
2026-03-27 13:33 ` David Hildenbrand (Arm)
2026-03-27 14:39 ` Zi Yan
2026-03-27 1:42 ` [PATCH v1 02/10] mm/khugepaged: remove READ_ONLY_THP_FOR_FS check Zi Yan
2026-03-27 7:29 ` Lance Yang
2026-03-27 7:35 ` Lance Yang
2026-03-27 9:44 ` Baolin Wang
2026-03-27 12:02 ` Lorenzo Stoakes (Oracle)
2026-03-27 13:45 ` Baolin Wang
2026-03-27 14:12 ` Lorenzo Stoakes (Oracle)
2026-03-27 14:26 ` Baolin Wang
2026-03-27 14:31 ` Lorenzo Stoakes (Oracle)
2026-03-27 15:00 ` Zi Yan
2026-03-27 16:22 ` Lance Yang
2026-03-27 16:30 ` Zi Yan
2026-03-28 2:29 ` Baolin Wang
2026-03-27 12:07 ` Lorenzo Stoakes (Oracle)
2026-03-27 14:15 ` Lorenzo Stoakes (Oracle)
2026-03-27 14:46 ` Zi Yan
2026-03-27 13:37 ` David Hildenbrand (Arm)
2026-03-27 14:43 ` Zi Yan
2026-03-27 1:42 ` [PATCH v1 03/10] mm: fs: remove filemap_nr_thps*() functions and their users Zi Yan
2026-03-27 9:32 ` Lance Yang
2026-03-27 12:23 ` Lorenzo Stoakes (Oracle)
2026-03-27 13:58 ` David Hildenbrand (Arm) [this message]
2026-03-27 14:23 ` Lorenzo Stoakes (Oracle)
2026-03-27 15:05 ` Zi Yan
2026-04-01 14:35 ` David Hildenbrand (Arm)
2026-04-01 15:32 ` Zi Yan
2026-04-01 19:15 ` David Hildenbrand (Arm)
2026-04-01 20:33 ` Zi Yan
2026-04-02 14:35 ` David Hildenbrand (Arm)
2026-04-02 14:38 ` Zi Yan
2026-03-27 1:42 ` [PATCH v1 04/10] fs: remove nr_thps from struct address_space Zi Yan
2026-03-27 12:29 ` Lorenzo Stoakes (Oracle)
2026-03-27 14:00 ` David Hildenbrand (Arm)
2026-03-30 3:06 ` Lance Yang
2026-03-27 1:42 ` [PATCH v1 05/10] mm/huge_memory: remove READ_ONLY_THP_FOR_FS from file_thp_enabled() Zi Yan
2026-03-27 12:42 ` Lorenzo Stoakes (Oracle)
2026-03-27 15:12 ` Zi Yan
2026-03-27 15:29 ` Lorenzo Stoakes (Oracle)
2026-03-27 15:43 ` Zi Yan
2026-03-27 16:08 ` Lorenzo Stoakes (Oracle)
2026-03-27 16:12 ` Zi Yan
2026-03-27 16:14 ` Lorenzo Stoakes (Oracle)
2026-03-29 4:07 ` WANG Rui
2026-03-30 11:17 ` Lorenzo Stoakes (Oracle)
2026-03-30 14:35 ` Zi Yan
2026-03-30 16:09 ` WANG Rui
2026-03-30 16:19 ` Matthew Wilcox
2026-04-01 14:38 ` David Hildenbrand (Arm)
2026-04-01 14:53 ` Darrick J. Wong
2026-03-27 1:42 ` [PATCH v1 06/10] mm/huge_memory: remove folio split check for READ_ONLY_THP_FOR_FS Zi Yan
2026-03-27 12:50 ` Lorenzo Stoakes (Oracle)
2026-03-30 9:15 ` Lance Yang
2026-03-27 1:42 ` [PATCH v1 07/10] mm/truncate: use folio_split() in truncate_inode_partial_folio() Zi Yan
2026-03-27 3:33 ` Lance Yang
2026-03-27 13:05 ` Lorenzo Stoakes (Oracle)
2026-03-27 15:35 ` Zi Yan
2026-03-28 9:54 ` kernel test robot
2026-03-28 9:54 ` kernel test robot
2026-03-27 1:42 ` [PATCH v1 08/10] fs/btrfs: remove a comment referring to READ_ONLY_THP_FOR_FS Zi Yan
2026-03-27 13:05 ` Lorenzo Stoakes (Oracle)
2026-03-27 1:42 ` [PATCH v1 09/10] selftests/mm: remove READ_ONLY_THP_FOR_FS in khugepaged Zi Yan
2026-03-27 13:05 ` Lorenzo Stoakes (Oracle)
2026-03-27 1:42 ` [PATCH v1 10/10] selftests/mm: remove READ_ONLY_THP_FOR_FS from comments in guard-regions Zi Yan
2026-03-27 13:06 ` Lorenzo Stoakes (Oracle)
2026-03-27 13:46 ` [PATCH v1 00/10] Remove READ_ONLY_THP_FOR_FS Kconfig David Hildenbrand (Arm)
2026-03-27 14:26 ` Zi Yan
2026-03-27 14:27 ` Lorenzo Stoakes (Oracle)
2026-03-27 14:30 ` Zi Yan
2026-04-05 17:38 ` Nico Pache
2026-04-06 1:59 ` Zi Yan
2026-04-06 16:17 ` Nico Pache
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