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From: Shakeel Butt To: Jiayuan Chen Cc: linux-mm@kvack.org, Tejun Heo , Johannes Weiner , Michal =?utf-8?Q?Koutn=C3=BD?= , Jonathan Corbet , Andrew Morton , Axel Rasmussen , Yuanchu Xie , Wei Xu , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Roman Gushchin , Muchun Song , Qi Zheng , cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 0/3] mm/lru_gen: add memory.lru_gen interface for cgroup v2 Message-ID: References: <20260121123955.84806-1-jiayuan.chen@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260121123955.84806-1-jiayuan.chen@linux.dev> X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 3D14C80007 X-Stat-Signature: fc8jdtgko6nni8baw6aaxa8cdg81iz6w X-Rspam-User: X-HE-Tag: 1769033992-5050 X-HE-Meta: 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 n25stDi1 0Q5jUgFhOtVxuAsL3Pf9eIJhgRg5n/giOG4GzkzoFYnRgERoQF8KrxhP69Y+BDzGr1jXB/hsRmoNxOw5D0qW9OT7LolBRHhIdLZazb6fygrQb+gHhYyVX+lKMl+iFyqKaX4DCjcFplWWAYV9aH9X1UJ5eXDK5+RDSJoQA7vN+XgNt5xJU3dlbAtYr1FyTBCbKIMM0zpFLdMrxrAfH4TEkLEoimp2+xLAM0t/WmUUvOI7xd6ErH/7rrtvXTRIEwksn69WTBr7gmC5XtcFleJT6YAR1dA== 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, Jan 21, 2026 at 08:39:46PM +0800, Jiayuan Chen wrote: > This patchset adds a memory.lru_gen interface to cgroup v2, allowing users > to interact with MGLRU directly on a specific cgroup without needing to > know the internal memcg_id. Unfortunetely we don't want to expose reclaim implementation specific interface to a cgroup. > > Motivation > ========== > Currently, the only way to perform aging or eviction on a specific memcg > is through the debugfs interface (/sys/kernel/debug/lru_gen), which > requires the memcg_id. However, there's no straightforward way to get the > memcg_id for a given cgroup path. This makes it difficult for users to > leverage MGLRU's proactive reclaim capabilities on specific cgroups. >From the next kernel version, this memcg_id will be inode number of the cgroup for this interface. So, a simple 'ls -id cgroup_path' would be sufficient for your use-case. The relevant series [1] is in mm-tree at the moment and if you want, you can backport it to your kernels. [1] https://lkml.kernel.org/r/20251225232116.294540-1-shakeel.butt@linux.dev