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[109.81.80.221]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-459e586a011sm133293865e9.19.2025.08.08.00.00.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 Aug 2025 00:00:38 -0700 (PDT) Date: Fri, 8 Aug 2025 09:00:37 +0200 From: Michal Hocko To: Zihuan Zhang Cc: "Rafael J . Wysocki" , Peter Zijlstra , Oleg Nesterov , David Hildenbrand , Jonathan Corbet , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , len brown , pavel machek , Kees Cook , Andrew Morton , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Catalin Marinas , Nico Pache , xu xin , wangfushuai , Andrii Nakryiko , Christian Brauner , Thomas Gleixner , Jeff Layton , Al Viro , Adrian Ratiu , linux-pm@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v1 0/9] freezer: Introduce freeze priority model to address process dependency issues Message-ID: References: <20250807121418.139765-1-zhangzihuan@kylinos.cn> <4c46250f-eb0f-4e12-8951-89431c195b46@kylinos.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4c46250f-eb0f-4e12-8951-89431c195b46@kylinos.cn> X-Rspam-User: X-Rspamd-Queue-Id: 5E85280010 X-Rspamd-Server: rspam06 X-Stat-Signature: 6o5sffrrrouo9fsraxfybm5kc6bfjym3 X-HE-Tag: 1754636440-394653 X-HE-Meta: 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 4sV1XMly r9ZPVvUMsRKe9vvfzM6VW+zKt8+DKzmImp21JeOcGKzOQ1agoiPXnYG2AY+RrrBqQ5x3gOHqkmfFzLMO6wXbcqs0FrjlddRpwHzG89Wgjck9QNvtRS6+zt2c26DB2RsDGFU2qxcgc6efR6fkyf3ixkFdRwf44Ya5/rL+KF20KCwEhluX5Z0yOaHO4P3+AClIVnxW4lkpWTiAtk2TFsXzkH4pbwY13nF96e21zNfOtnMJNyNmbwNYnjvCGNhdk0By0yfMivUDKxAdxleuSG2Cy7hAocytLbwPGxdKiMIvhZWBm97FZSz9X3PE6NSE2ezVzyChrlSbAGfzKwXI3/39HMJksDQ== 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 Fri 08-08-25 09:13:30, Zihuan Zhang wrote: [...] > However, in practice, we’ve observed cases where tasks appear stuck in > uninterruptible sleep (D state) during the freeze phase  — and thus cannot > respond to signals or enter the refrigerator. These tasks are technically > TASK_FREEZABLE, but due to the nature of their sleep state, they don’t > freeze promptly, and may require multiple retry rounds, or cause the entire > suspend to fail. Right, but that is an inherent problem of the freezer implemenatation. It is not really clear to me how priorities or layers improve on that. Could you please elaborate on that? -- Michal Hocko SUSE Labs