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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Matthew Wilcox , Bas van Dijk , Eero Kelly , Andrew Battat , Adam Bratschi-Kaye , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] selftests/mm: add folio_split() and filemap_get_entry() race test Message-Id: <20260314152751.101b5d04d3753f75027b9cd6@linux-foundation.org> In-Reply-To: <20260313114037.3593642-1-ziy@nvidia.com> References: <20260313114037.3593642-1-ziy@nvidia.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 967AC1A0005 X-Stat-Signature: pg8jn39b9rr79zgt57fdw5p9b7351xh9 X-Rspam-User: X-HE-Tag: 1773527274-39883 X-HE-Meta: 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 xk4TW49W fPc6nqbaGfAwFb8EKNXpgInYxWnme31tEMNrcxmhu3TvVRB7jR50NXwaxERCq1BzNG9Vy9tPupslvtOZ8kP7JLI+TZ0l7FOGVEWX3x5JOlOS1n+6xFaYMFx4AdwhqH1rWW7KtL5onPI3d8gdZtxxQ4M+GoSlAB6CQc/lHf8+0uAQRUEwPumbITwMwgxAfjWwVRLUpfWzAdU+TXt/xZR4VfWqrq/i9iQcPhrw902u4JVzDuosb7XgI1URPoLaWZywhJ856rpqAEi3knDhE0984K3QVZgQzmSWabGG5B3DnKp4Ai6S+/u34dZP6RG1/aj8S+UsYQqI71pekPnSae4UiCG36vn0rbezwP9P4PrjbcUF0gxpNVI4yKenYy1lAZ3IjYK+Yxu/eCeWPjH0= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 13 Mar 2026 07:40:37 -0400 Zi Yan wrote: > The added folio_split_race_test is a modified C port of the race condition > test from [1]. The test creates shmem huge pages shared by both a parent > and a child processes, where the parent process punches holes in the shmem > to cause folio_split() in the kernel and the child process reads the shmem > in 16 threads to cause filemap_get_entry() in the kernel. > filemap_get_entry() reads the folio and xarray split by folio_split() > locklessly. The original test[2] is written in rust and uses memfd (shmem > backed). This C port uses shmem directly. Cool. > Note: the initial rust to C conversion is done by Cursor. Hence the CaMeLcAsE "struct SharedCtl". Fair enough. > Link: https://lore.kernel.org/all/CAKNNEtw5_kZomhkugedKMPOG-sxs5Q5OLumWJdiWXv+C9Yct0w@mail.gmail.com/ [1] > Link: https://github.com/dfinity/thp-madv-remove-test [2] I couldn't immediately find any licensing info there. Bas and Adam, please advise? And sending your Signed-off-by's would be appropriate. Thanks.