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[109.81.86.48]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-482a5b816c0sm1827065f8f.33.2026.08.17.01.31.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Aug 2026 01:31:10 -0700 (PDT) Date: Mon, 17 Aug 2026 10:31:09 +0200 From: Michal Hocko To: Song Hu Cc: akpm@linux-foundation.org, linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, hannes@cmpxchg.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, zhuhui@kylinos.cn, joshua.hahnjy@gmail.com, audra@redhat.com, bingfangguo@tencent.com Subject: Re: [PATCH] mm: memcg: flush empty per-cpu stock slots on memcg offlining Message-ID: References: <20260817025917.66233-1-husong@kylinos.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260817025917.66233-1-husong@kylinos.cn> X-Stat-Signature: ywibca1ut844rfm3ne4kbobmf3fswnj6 X-Rspamd-Queue-Id: 2BC09A0009 X-Rspamd-Server: rspam03 X-Rspam-User: X-HE-Tag: 1786955472-189709 X-HE-Meta: U2FsdGVkX1/NOQGvaqmbT4obzmAkuzV/S7Irh6xyHASRfB6+JgjCQPfyJfYDKMbqKRu+9uoaAcI/W6PBb3j4nO0naBG12wqdOlmg3QnVv3dxBL6FHPELV0HOqqviaYUPi9imLY4QqJzcOSk4hMUDIPvTv8PRZuhEMrungWlT9NJfaebypMEMv4n3hOztPiSnI4VX5Eu9kQmT1LmKaZUUAc66NzTbAkAGpcziL3ULCKR/6bdyTcMy+IlLxsdVaUxPGNFYJoGr6S+4AH4cOkUpQ37r9/iYx4S+OEv0++XDzLf73ikqpUy9Zb3UtVASwYNc6XZIvRq+QSvyEwjZUWwuRBo+hSk4uFHxGfuXn+zzZBLcvhtDaRcohmEBXAvOo5zcNYxSgkLPhqiIi75d40Vz+OHAB2I9jSN9pF1BuRph7jGuXq3NwYzNssXnaJYcEuMcwpDAgyrcJCbxRfD7LA58U3bGdsFENTpbjJqsfP/76yTLDKSLEi3F+O2gByyOUW/LMwJwHMIDeFiMD1Kc2nIpbOB4j+2yxw5wSkLe7k0XxV0gdhj5w1KIjc43Hery2wDTOD0Ftg9bgkX2DIV9DdOj3esJUfIf11A3RefMzin7koLYctfg4fLQlig8FxS37zn3Ww7jVgXzi+YCNeiiKI4YhitUBN+Bn73jc328D3jFIMdevt76Cch3zbDBs4Osy9mNH0uiZKMBYbbranqUuEElHU/x4XkDnBkgzapKXN87subVZZNdddncdfnQtLJBacjTu392fSpZTfJ5ji93KFtpxlKC/L2g0C8gEpjEx7HloH/JowIfIQNS8e4drLaYxW+KSNmvytnLK53Opom7hEyNE2y23Lt+7rIhrYISu4J7H3/FcQ9G31pYtvCJdjul1P6Nku39Mp6OkBT0IwDXhWoMIVl7XBBej4RkDcUIHdxtB5WDDZtMkb1DjS9lFvZG3dESeZDUDzatTSXt5+BRuYC I68teHp+ zvj5Hhg36xvVlXKrovOqjvGsgu8Q8OOhnwqUtrzER15/vHzFwcZSIdm7j+6b1HTBtOHiUSKOFQySHiPahFgryZKuuKrCBrMi/cDEOq7c7r2apmb8p5f2fS9m5K9ARrSr0f6Tn8mXCYqotJRH0bmPNZtmJAd00luqltf9HqjQXfq69bH8a/yeXziAy791BHyDMy54AFF53M1KERUMXLRL4Z/zl7+x0vplvq89k72kBk+Udv3Q/deWi3Ypak9Qb8PI2ntvHNhmkFe4SYd+/TxN1Lz89PfSvKQMV8Mqbl3BHzk+swlFFEVsyv0p7Ie6u78wNQmEhMj5BfcZdyXAr5GP42sUNf/F3jhmElCwYDcu+YwSSUFeFrHplICy5yopyhiLuMt/I1K2xlu7G/BfzkRih8QSCwVaLUOvl/pIdpAW9bQt1T5RL9HzoeqVNZw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon 17-08-26 10:59:17, Song Hu wrote: > refill_stock() takes a css reference for each cached memcg slot and > mem_cgroup_css_offline() relies on drain_all_stock() to release those > references before the cgroup can finish dying. > > consume_stock() can drive a slot's nr_pages to zero while its cached[] > pointer stays set. Is there any specific reason why the memcg stays in the cache slot without any pages? -- Michal Hocko SUSE Labs