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Sat, 26 Sep 2026 15:06:03 -0700 (PDT) Received: from [192.168.1.106] ([198.8.77.135]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-341447576b9sm19647203eec.15.2026.09.26.15.06.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 26 Sep 2026 15:06:03 -0700 (PDT) Message-ID: <0367c089-a2da-42ad-ae9f-fc61dd220d1a@kernel.dk> Date: Sat, 26 Sep 2026 16:06:02 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 00/15] io_uring: thread identity handoff for blocking inline issue To: Ming Lei Cc: io-uring@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, tglx@kernel.org, mingo@redhat.com, peterz@infradead.org References: <20260911154148.644489-1-axboe@kernel.dk> Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260926_150605_616421_FAEDECD7 X-CRM114-Status: GOOD ( 16.28 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 9/26/26 10:04 AM, Ming Lei wrote: > On Fri, Sep 11, 2026 at 09:40:50AM -0600, Jens Axboe wrote: >> Hi, >> > > ... > >> >> This is obviously an RFC, in terms of what I'd love people to take a >> closer look at: >> >> - The scheduler hook and the identity move itself, kernel/thread_handoff.c. >> Is the set of refused states complete enough, and is moving >> thread group leadership this way (the leader must stay first on >> ->thread_head, like de_thread() keeps it) acceptable / kosher. >> - The x86 and arm64 register state handling. x86 refuses AMX users, >> and arm64 refuses SME. >> - Whether anyone relies on a task's user identity staying on one >> task_struct in ways not covered above in the series. > > This way may break ublk server given 'task_struct *' can be changed > because the server issues blocking OP(fallocate, ...), then the > `current` check in ublk_dispatch_req() can be hit. Yep, which is why is isn't enabled there. > Also there is risk in 'task_struct *' keyed bpf task storage. > > task_work queuing could become tricky too. Like the above, the series does attempt to handle that. -- Jens Axboe