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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , 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 7.2 v2 12/12] selftests/mm: remove READ_ONLY_THP_FOR_FS from comments in guard-regions Message-ID: References: <20260413192030.3275825-1-ziy@nvidia.com> <20260413192030.3275825-13-ziy@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 5A2EE140008 X-Stat-Signature: h7y3ezh3xmy868mwpn9i5axu6dxc8tsh X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1776119353-761898 X-HE-Meta: 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 OXoAOTWv +foorH4qOPcGRCMxupVPwwvcVFjdx0iGc1xyE5IxJKo05aQC+uYP27/ux1FoOIi7Odsp72KaIjCeXiRjgNd5VvjIrg7Oblb73ythvEL/0wNzWWnYRtRdfTrnNZ9btyy33nqdTrzhd5ym5NztELpSOKEHKG1p/A9cXJgNcnbowbFl9shgT6E/wJO4Cjlq+izOZnC7CP6+9YKkTdP+FRjfV3WyTAOB0J6JzJ5GYmPZY6mL67ptagSIropJIuKkBs3jXgsQjIeh6eRSw7WwAme5t3lHMenGxIrpRAuPk9wA7xPkG0Fw= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Apr 13, 2026 at 04:51:28PM -0400, Zi Yan wrote: > On 13 Apr 2026, at 16:47, Matthew Wilcox wrote: > > > On Mon, Apr 13, 2026 at 03:20:30PM -0400, Zi Yan wrote: > >> +++ b/tools/testing/selftests/mm/guard-regions.c > >> @@ -2205,7 +2205,7 @@ TEST_F(guard_regions, collapse) > >> > >> /* > >> * We must close and re-open local-file backed as read-only for > >> - * CONFIG_READ_ONLY_THP_FOR_FS to work. > >> + * MADV_COLLAPSE to work. > > > > Is this true? Does MADV_COLLAPSE refuse to work on writable files? > > Should we delete some code here as well as fix the comment? ;-) > > file_thp_enabled() used by __thp_vma_allowable_orders() refuses > writable files with inode_is_open_for_write(). That should prevent > MADV_COLLAPSE from working on writable files. That sounds like more code that was added for RO_THP and should be deleted? See commit e6be37b2e7bd