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b=oC3uTsfTyKDIqZaisG0WKKVB9EmpHhBOnOWHaWAApxwTgMVn/0QkZo2931uJNYAwq BbaussuEh0GEfRSPvu9n5LqvBmGjar+0gKreZCMQXomYlI/6vZ+cPa+IY+3mY85xwY /JV5W6iIEQcQKRvuls3jvAagU2NjEVN26aOw0o1KQuYuQ3wxEqW3wA3uQdmrLhJZK3 45uVyOllo5Rg1GKGSKyCx+3xbycfWE/+dnvmgeeJyI/82eit9khgZ8E6eZdbidd3Iy 0IG2oHhRKvZHhboVqRj0Wwrjh1okHLHd+mPSU3IgU46AZVJgFZ0xYLhCz23FoqXrY9 2Epl32jaS4kJg== Date: Thu, 20 Feb 2025 11:08:00 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: Waiman Long , Peter Zijlstra , Ingo Molnar , Will Deacon , Andrew Morton , Boqun Feng , Joel Granados , Anna Schumaker , Lance Yang , Kent Overstreet , Yongliang Gao , Tomasz Figa , Sergey Senozhatsky , linux-kernel@vger.kernel.org, Linux Memory Management List Subject: Re: [PATCH 1/2] hung_task: Show the blocker task if the task is hung on mutex Message-Id: <20250220110800.42ce6b1b8e94a3b998d533a5@kernel.org> In-Reply-To: <20250219185810.57561c69@gandalf.local.home> References: <173997003868.2137198.9462617208992136056.stgit@mhiramat.tok.corp.google.com> <173997004932.2137198.7959507113210521328.stgit@mhiramat.tok.corp.google.com> <20250219112308.5d905680@gandalf.local.home> <0fa9dd8e-2d83-487e-bfb1-1f5d20cd9fe6@redhat.com> <20250219152435.35077ac3@gandalf.local.home> <20250220080908.fc1494f0f7c611b48fbe0f8b@kernel.org> <20250219185810.57561c69@gandalf.local.home> 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: rspam04 X-Rspamd-Queue-Id: 562D4140007 X-Stat-Signature: nm5jy41z5781uwu3yy3k483xxzy6zm7q X-Rspam-User: X-HE-Tag: 1740017284-737829 X-HE-Meta: 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 yF7oeJh2 2ArVQn84c6wHEmX4Kwk26pPvlKivnAMaE/amezOHqAxVMqJET/WnNwRTat1KU8YyayA/7PF1yF0C6IZBDLnsR7uAlxh3893a0g2tTnjx3iXuEBFqHNpqeOSOhbsPz0gempAbYWvFFlMHrpnMALLx29iQS1X8R6sxAjMua9Eu5pyZcFWAPm0V7mlNyzV143m43zjVDX1ZfwZeupRregMD0HmbM92izdatefQ2ojA8W8MV7jibnOClFKjYndte6b6bB4844ZU0HCpNxW49dgSiJQ7lHp/2ahl/zp4HXkgQkekoJ7qfC8xzwxEu7pO2o+j605F5NnGEWh3BfEZ09Z3I/K8yk1qpzU655oOnTj/GyTNZUYC9J4XaibGAUABB8x+nWbtV/Lmm+Ksd5cfUIcCNlUjgWa0ElY0gptMH3RzpLJfCH/LcULIobQx3ySLySAjMiegtM 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, 19 Feb 2025 18:58:10 -0500 Steven Rostedt wrote: > On Thu, 20 Feb 2025 08:09:08 +0900 > Masami Hiramatsu (Google) wrote: > > > So something like this? > > > > unsigned int block_flags; > > union { > > struct mutex *mutex; > > struct rwsem +rwsem; > > struct rtmutex *rtmutex; > > } blocked_on; > > > > enum { > > BLOCKED_ON_MUTEX; > > BLOCKED_ON_RWSEM; > > BLOCKED_ON_RTMUTEX; > > BLOCKED_ON_IO; > > } block_reason; > > > > For the safety, we may anyway lock the task anyway, but that is the > > same as stacktrace. > > Why not make it into a single entity? > > struct blocked_on { > unsigned int flags; > union { > struct mutex *mutex; > struct rwsem *rwsem; > struct rtmutex *rtmutex; > } blocked_on; > }; Yes, and we also merge current mutex_waiter too. Thank you, > > -- Steve > -- Masami Hiramatsu (Google)