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Petersen" , Matthew Wilcox , Dave Chinner , linux-kernel@vger.kernel.org Subject: Re: [LSF/MM/BPF TOPIC] untorn buffered writes Message-ID: References: <20240228061257.GA106651@mit.edu> <9e230104-4fb8-44f1-ae5a-a940f69b8d45@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9e230104-4fb8-44f1-ae5a-a940f69b8d45@oracle.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Stat-Signature: niqiyqascjzagf1ohkkn1sbtfjnkcinr X-Rspamd-Queue-Id: 7CB77C0017 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1716469184-759061 X-HE-Meta: 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 aWAi1MWF 5Ot3Jt/UZkCBPeXCjW0/qBA4A6hC0N9mN4gioiLSht87dhhrq3Z+n3+vXMpnT5sJaHOe75bBHDmIlS7/p4i1GwQ3C/NA5ZHoW52Z7pFKySZe47lc8EaP6vuAXp7VRKYKA1DsjK3rMRinwtANR0tUe1H1t3cy5ZN/6kn+6DPdj+Ay+MsoroJz2gAzYcJQH1rl6XJsT99D1cW00nKHB/UtDAQq56z95ePC5/q9kD+CTcG60obfe9MmvKggkyOpadTK2RiGEF7yxzZVyABisgTneLafGMQ4snZqOI+AmdmvmdghKM4h2RsItyd/LQBxlfj6dS4BbxgOhZzAEe1FpsIdGHY7Y1Ih6b5j5zIpwncuNJ/5F1VLoRf6EntuQWMDLmIpDh4YZAQ0JuBRYX1ebZOOUxw+o8c/AeiZo0kzDEkZUgEcsDQJEypA+GiTXyyoV/JBKmZk+2k8vdYRyCHMO5Ns5CmQ2LmXIicZ5N775dvJPtCZ1FiDZg9FLytNzGezCJPjSXZ+hnWkGvFoRLxBXAdxslhApqtgsUONV5jbWBFY6HRGKTZY= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, May 15, 2024 at 01:54:39PM -0600, John Garry wrote: > On 27/02/2024 23:12, Theodore Ts'o wrote: > > Last year, I talked about an interest to provide database such as > > MySQL with the ability to issue writes that would not be torn as they > > write 16k database pages[1]. > > > > [1] https://urldefense.com/v3/__https://lwn.net/Articles/932900/__;!!ACWV5N9M2RV99hQ!Ij_ZeSZrJ4uPL94Im73udLMjqpkcZwHmuNnznogL68ehu6TDTXqbMsC4xLUqh18hq2Ib77p1D8_4mV5Q$ > > > > After discussing this topic earlier this week, I would like to know if there > are still objections or concerns with the untorn-writes userspace API > proposed in https://lore.kernel.org/linux-block/20240326133813.3224593-1-john.g.garry@oracle.com/ > > I feel that the series for supporting direct-IO only, above, is stuck > because of this topic of buffered IO. Just my 2 cents, but I think supporting untorn I/O for buffered I/O is an amazingly bad idea that opens up a whole can of worms in terms of potential failure paths while not actually having a convincing use case. For buffered I/O something like the atomic msync proposal makes a lot more sense, because it actually provides a useful API for non-trivial transactions.