From: Andrew Morton <akpm@linux-foundation.org>
To: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@kernel.org>,
"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>,
Lorenzo Stoakes <ljs@kernel.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 v5 01/14] mm/khugepaged: remove READ_ONLY_THP_FOR_FS check
Date: Thu, 30 Apr 2026 08:04:21 -0700 [thread overview]
Message-ID: <20260430080421.902b8e38df2a3b79421396bf@linux-foundation.org> (raw)
In-Reply-To: <4C10A739-4931-4922-B2C2-245A610C0120@nvidia.com>
On Thu, 30 Apr 2026 10:37:52 -0400 Zi Yan <ziy@nvidia.com> wrote:
> + * MADV_COLLAPSE ignores shmem huge config, so do not check shmem
> > + *
> > + * TODO: once shmem always calls mapping_set_large_folios() on its
> > + * mapping, the shmem check can be removed.
> > + */
> > + VM_WARN_ON_ONCE(!is_shmem && !mapping_pmd_folio_support(mapping));
>
> sashiko asked:
> Is it possible for userspace to intentionally trigger this warning via
> madvise(MADV_COLLAPSE) on an unsupported read-only file? Although in
> a later commit, modified file_thp_enabled() will prevent this.
>
> Answer:
> It is possible when CONFIG_READ_ONLY_THP_FOR_FS is enabled, but it is
> unlikely a kernel will be shipped at this exact commit.
Yeah, let's not worry about minor bisection holes.
next prev parent reply other threads:[~2026-04-30 15:04 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-29 15:29 [PATCH v5 00/14] Remove CONFIG_READ_ONLY_THP_FOR_FS and enable file THP for writable files Zi Yan
2026-04-29 15:29 ` [PATCH v5 01/14] mm/khugepaged: remove READ_ONLY_THP_FOR_FS check Zi Yan
2026-04-30 14:37 ` Zi Yan
2026-04-30 15:04 ` Andrew Morton [this message]
2026-05-04 3:48 ` Nico Pache
2026-04-29 15:29 ` [PATCH v5 02/14] mm/khugepaged: add folio dirty check after try_to_unmap() Zi Yan
2026-04-30 15:11 ` Zi Yan
2026-05-04 3:53 ` Nico Pache
2026-05-06 5:23 ` Lance Yang
2026-04-29 15:29 ` [PATCH v5 03/14] mm/huge_memory: remove READ_ONLY_THP_FOR_FS from file_thp_enabled() Zi Yan
2026-05-04 3:57 ` Nico Pache
2026-04-29 15:29 ` [PATCH v5 04/14] mm/khugepaged: remove READ_ONLY_THP_FOR_FS check in hugepage_enabled() Zi Yan
2026-05-04 4:00 ` Nico Pache
2026-04-29 15:35 ` [PATCH v5 05/14] mm: remove READ_ONLY_THP_FOR_FS Kconfig option Zi Yan
2026-05-04 4:02 ` Nico Pache
2026-04-29 15:35 ` [PATCH v5 06/14] mm: fs: remove filemap_nr_thps*() functions and their users Zi Yan
2026-04-29 15:35 ` [PATCH v5 07/14] fs: remove nr_thps from struct address_space Zi Yan
2026-05-04 4:11 ` Nico Pache
2026-04-29 15:35 ` [PATCH v5 08/14] mm/huge_memory: remove folio split check for READ_ONLY_THP_FOR_FS Zi Yan
2026-04-29 15:35 ` [PATCH v5 09/14] mm/truncate: use folio_split() in truncate_inode_partial_folio() Zi Yan
2026-04-30 15:12 ` Zi Yan
2026-04-29 15:35 ` [PATCH v5 10/14] fs/btrfs: remove a comment referring to READ_ONLY_THP_FOR_FS Zi Yan
2026-04-29 15:35 ` [PATCH v5 11/14] selftests/mm: remove READ_ONLY_THP_FOR_FS in khugepaged Zi Yan
2026-04-30 15:16 ` Zi Yan
2026-04-30 15:27 ` Zi Yan
2026-05-04 4:23 ` Nico Pache
2026-05-04 10:11 ` Nico Pache
2026-04-29 15:35 ` [PATCH v5 12/14] selftests/mm: remove READ_ONLY_THP_FOR_FS code from guard-regions Zi Yan
2026-04-29 15:35 ` [PATCH v5 13/14] mm/khugepaged: enable clean pagecache folio collapse for writable files Zi Yan
2026-04-30 15:18 ` Zi Yan
2026-04-29 15:35 ` [PATCH v5 14/14] selftests/mm: add writable-file collapse tests for khugepaged Zi Yan
2026-04-29 16:13 ` [PATCH v5 00/14] Remove CONFIG_READ_ONLY_THP_FOR_FS and enable file THP for writable files Andrew Morton
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