From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-183.mta0.migadu.com (out-183.mta0.migadu.com [91.218.175.183]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 39A532DC321 for ; Wed, 21 Jan 2026 22:20:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.183 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769034004; cv=none; b=JBcD4XgOw6GgfaoWrBTrvIwOZxe6Hsme62i/YhWU8BRE2rQ764bodohJF0tUPAqvPy6c7KKeZFKld2Woi+AcfjzNZlnFPm/swWbmBZjbO+8uTMeDV0TC+T5Rmho4rIZBBBZI0ufq2yim04Fnx+a1MDc0Q7ws+NNglylfTXwEMl0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769034004; c=relaxed/simple; bh=yb3EVg95+PjCTvf2Xtv6yyaE4fFqLPPjH+MGY6BGmeQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=T+poOSyS7Hi8J43o1tu4Pgr2+bFp2zyaBLc3rtTi4IZSDa01uZ30pgWsMXLx7k1IqxkFiG7JjrvqMHcl7vTpLIBGVuT8oQCYkM9XqxBnVShUbfxERkOzPnO6vxjHKydU5mZmBWGHC4jnJKLMjfjrat5GIXYEOXIPQHjKUcb+xwE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=bRcPWOGZ; arc=none smtp.client-ip=91.218.175.183 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="bRcPWOGZ" Date: Wed, 21 Jan 2026 14:19:44 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1769033989; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=HoQi6KkVwO2LhgzMpx+nRVqZde/RMh0LYhGYMNHF+wI=; b=bRcPWOGZvCAF46Vb6d+TQK7NJXXCA1nyBDuGiR30fw6T2n2RgwTpzNZsEoy7Sw8d7wFm6H dFr++EqcJGqK4eMkbiF/b08+spW4WaOIL49mAPk8Xb9i4ovQiwLgdCvZbi5lkyrSgh6UW+ dV28mKXR+f8sdVTOAWqWhdjoPIBVXz8= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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