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([2601:188:c100:5710:627d:9ff:fe85:9ade]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6e65d7791cdsm81784096d6.9.2025.02.19.19.49.09 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 19 Feb 2025 19:49:10 -0800 (PST) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: <524bd2b9-5322-4012-b1d0-b76edb84ec4f@redhat.com> Date: Wed, 19 Feb 2025 22:49:09 -0500 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] hung_task: Show the blocker task if the task is hung on mutex To: Sergey Senozhatsky , Masami Hiramatsu Cc: Steven Rostedt , Waiman Long , Peter Zijlstra , Ingo Molnar , Will Deacon , Andrew Morton , Boqun Feng , Joel Granados , Anna Schumaker , Lance Yang , Kent Overstreet , Yongliang Gao , Tomasz Figa , linux-kernel@vger.kernel.org, Linux Memory Management List 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> <20250220-112040-neomutt-senozhatsky@chromium.org> In-Reply-To: <20250220-112040-neomutt-senozhatsky@chromium.org> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: bcRZ_499QN_cwTEW-Vd0eGoap46X3ErQitcrWQ9q4f4_1740023351 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: EE2D54000A X-Rspamd-Server: rspam07 X-Stat-Signature: dqykyz8gqyxn9qqai5rjz6bokaq53t1p X-HE-Tag: 1740023353-91792 X-HE-Meta: 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 GrT425A7 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000464, 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 2/19/25 9:45 PM, Sergey Senozhatsky wrote: > On (25/02/20 08:09), Masami Hiramatsu 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; > I totally like this and always wanted to have something simlar, > something for all "sleepable" synchronization primitives, lightweight > enough (memory and CPU usage wise) to run on consumer devices. I was > thinking of a rhashtable where each entry represents "sleepable" > primitive with a "owner" pointer and a list of "blocked on" tasks. > But I'm sure you'll have a better idea. > > If I may add a couple of "wishes", can we also add: > - completions (so that things like wait_for_completion and > synchronize srcu get covered) > - wait on bit (so that things like lock_buffer and so on get covered) Bit lock doesn't have a owner field to track the owning task. Cheers, Longman >