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Sat, 26 Sep 2026 09:04:25 -0700 (PDT) Received: from fedora-laptop ([172.245.82.59]) by smtp.gmail.com with ESMTPSA id 006d021491bc7-6d581dc58dasm6182919eaf.4.2026.09.26.09.04.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 26 Sep 2026 09:04:25 -0700 (PDT) Date: Sat, 26 Sep 2026 11:04:14 -0500 From: Ming Lei To: Jens Axboe 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 Subject: Re: [RFC PATCH 00/15] io_uring: thread identity handoff for blocking inline issue Message-ID: References: <20260911154148.644489-1-axboe@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260911154148.644489-1-axboe@kernel.dk> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260926_090427_562849_E01AF62F X-CRM114-Status: GOOD ( 13.28 ) 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 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. Also there is risk in 'task_struct *' keyed bpf task storage. task_work queuing could become tricky too. Thanks, Ming