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Thu, 21 Nov 2024 05:28:13 -0800 (PST) Received: from [192.168.42.195] ([163.114.131.193]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-aa4f42d328dsm81636666b.109.2024.11.21.05.28.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 Nov 2024 05:28:13 -0800 (PST) Message-ID: Date: Thu, 21 Nov 2024 13:29:05 +0000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Pavel Begunkov Subject: Re: [PATCH v9 06/11] io_uring: introduce attributes for read/write and PI support To: Christoph Hellwig Cc: Anuj Gupta , axboe@kernel.dk, kbusch@kernel.org, martin.petersen@oracle.com, anuj1072538@gmail.com, brauner@kernel.org, jack@suse.cz, viro@zeniv.linux.org.uk, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, gost.dev@samsung.com, linux-scsi@vger.kernel.org, vishak.g@samsung.com, linux-fsdevel@vger.kernel.org, Kanchan Joshi References: <20241114104517.51726-1-anuj20.g@samsung.com> <20241114104517.51726-7-anuj20.g@samsung.com> <20241118125029.GB27505@lst.de> <2a98aa33-121b-46ed-b4ae-e4049179819a@gmail.com> <20241118170329.GA14956@lst.de> <4f5ef808-aef0-40dd-b3c8-c34977de58d2@gmail.com> <20241119124938.GA30988@lst.de> Content-Language: en-US In-Reply-To: <20241119124938.GA30988@lst.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241121_052816_305959_774080EE X-CRM114-Status: GOOD ( 11.63 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 11/19/24 12:49, Christoph Hellwig wrote: > On Mon, Nov 18, 2024 at 05:45:02PM +0000, Pavel Begunkov wrote: >> Exactly, _fast path_. PI-only handling is very simple, I don't buy >> that "complicated". If we'd need to add more without an API expecting >> that, that'll mean a yet another forest of never ending checks in the >> fast path effecting all users. > > Well, that's a good argument for a separate opcode for PI, or at least No, it's not. Apart from full duplication I haven't seen any PI implementation that doesn't add overhead to the io_uring read-write path, which is ok, but pretending that dropping a new opcode solves everything is ill advised. And I hope there is no misunderstanding on the fact that there are other criteria as well, and what's not explicitly mentioned is usually common sense. For example, it's supposed to be correct and bug free as well as maintainable. > for a 128-byte write, isn't it? I have real hard time trying to find > a coherent line in your arguments. When coming from invalid assumptions everything would seem incoherent. And please, I'm not here to humour you, you can leave your crude statements for yourself, it's getting old. -- Pavel Begunkov