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([2601:188:c100:5710:627d:9ff:fe85:9ade]) by smtp.gmail.com with ESMTPSA id 006d021491bc7-5fce96898aesm1741888eaf.26.2025.02.19.18.21.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 19 Feb 2025 18:21:33 -0800 (PST) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: <0948872d-06cf-45da-81d0-397197fdbc67@redhat.com> Date: Wed, 19 Feb 2025 21:21:31 -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: "Masami Hiramatsu (Google)" , 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 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> <20250220075639.298616eb494248d390417977@kernel.org> <20250219185531.1140c3c4@gandalf.local.home> <20250220110707.a314d394ccf68575047e75cb@kernel.org> In-Reply-To: <20250220110707.a314d394ccf68575047e75cb@kernel.org> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: rn-_vlDU3_1KBWV2RKiPlq7_vbSTdjgpMRsox8hqaDs_1740018094 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: F040A140002 X-Stat-Signature: kde338n7i464yqseid7guwfgdgp7jkny X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1740018096-573335 X-HE-Meta: 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 3bSdcy9W 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000623, 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 9:07 PM, Masami Hiramatsu (Google) wrote: > On Wed, 19 Feb 2025 18:55:31 -0500 > Steven Rostedt wrote: > >> On Thu, 20 Feb 2025 07:56:39 +0900 >> Masami Hiramatsu (Google) wrote: >> >>>>>> this field, we don't need to take lock, though taking the wait_lock may >>>>>> still be needed to examine other information inside the mutex. >>> Do we need to take it just for accessing owner, which is in an atomic? >> Updating the task_struct would be in the same location as the blocked_on is >> anyway. I would make it into a wrapper function that is a nop when disabled. > Should we make it depends on DEBUG_MUTEXES too? I think no. We can introduce > a different kconfig and wrapper function which calls debug_mutex_*(). No, I don't think so. In fact, the mutex debug code can make use of the new fields for additional checking. I believe DEBUG_MUTEXES should select the new option. Cheers, Longman