From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f178.google.com (mail-qt1-f178.google.com [209.85.160.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6BEE534EEFD for ; Wed, 22 Jul 2026 13:48:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784728139; cv=none; b=UfzCbYUXyISW9xVZFCIKlpAmaadbSZfkLkcHhz/rYUElGUk+8n5hje/daPZJBO7MPeIyAsvvUX2FjpxKSWzgDLm2DatYNM/FPdk6Q/DBbW205Pn3vSD3l4TQNFWwTIzCPNsyPDAZqFZgA6ZMwd2U0fJscPNvYHYrI/1DtK1eeEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784728139; c=relaxed/simple; bh=JAIqzpQM3gUx7M+gDSziic1KcB43W58VAXiVvJF0/Hk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gqVhgSwIExyLCiTjCF32KcYb52Abm6+pjuur7KvXjnSH/LdLPbh0SJTKQpqCGsXll0zKy2JHaWglK5NGBpVIIz4ohY+0iujwvi0P7JIRAOj/Ky/HjzLvayg9uPVZqwNDP0+TRta3i4rtYI0Ltrb+tcchltwVlVmP/KPb9O8Mx3Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net; spf=pass smtp.mailfrom=gourry.net; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b=GfLa6fHj; arc=none smtp.client-ip=209.85.160.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gourry.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b="GfLa6fHj" Received: by mail-qt1-f178.google.com with SMTP id d75a77b69052e-51c01089e8aso66365561cf.2 for ; Wed, 22 Jul 2026 06:48:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1784728136; x=1785332936; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=LI4otu0+1hHJyrtu/tBxz3iTtloCysub9k9iNgYv1gk=; b=GfLa6fHjBw5k5Cgmz1whJ5nETVeelFxMT26tNktv/o76lhNb8g352TR5NSgzxj0xK/ l99ZU3otNIqIWf5NPRZOUByX/rsuPiQ11f/76fJZU6VdndYf/hECk1QXXGmtm6zxg/D+ Jp3L7vWik0zmayA89l50HzOSWyCZrphTG1lt1EZnBbJQbWY5rLr8WS00j1qAY7moV6C6 lTJ7XSZYNDD8dlO/MPxVy2EEZD8SCjSLPMCaZCsQD7e37hasV8TP4a+NhorAAbZ0Ohhs 6nlqtYbIICyZZQkN6OqTZwVx6r17L7v2FbkjPkZ0Eqhsumnot7b9+N7Dj0SpPbVDkztD g8YA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784728136; x=1785332936; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=LI4otu0+1hHJyrtu/tBxz3iTtloCysub9k9iNgYv1gk=; b=XLyNUiYkWT+yext1ukEfySYsnYsrWj9f8dOXm+TQ7WIHaIW2zJH7cwGDpLGrBecYPo gf01XPYyT9pzADw7clYSF214CYO9jtVpKgjePotSbiERIwMyuhUc+ZPNR8LYD7toZC62 DhClvadDv+tHM4k3BqUEZJ7qqL/ULGZ8106PWqy01/Lp+inCi9/CkJgWQPkbi+lhywBq uk8V+MkfoxoWnQULOvpLIqzP30cRmuEcEcoAx8U/en34JIMoQPhJNkQtByZQkNl+8FKR 5LdYmTj+KgHORSwo1sannxikk+TtzgVtUg4r8FOz01GRYXVzTGrOvRvLULHHjquMe4Kd Lu9A== X-Forwarded-Encrypted: i=1; AHgh+RqpYd983nCHo/fWNPGHnAe5Su05iZ7qglX3/0qeUFcg2dYKT958AZhuTdPbILthe4TCP0yk6KvP@vger.kernel.org X-Gm-Message-State: AOJu0Yw/Yyd5hcCHtxTEK42FDEsdw2Tk2vHkxSgWLvLhoK+qWnUXrPIw L0TZWeLnxLNLF/5FQJOoJR9z/Rf/BZPrjZxe2+hKFpZJoaZh3LJEVWp5zvexiYUR8pY= X-Gm-Gg: AR+sD12YeZ5tYs3CUYgeAse843XS5Kl+ntfha3iYYh/1sCYOxAb29g8FxyY85EuNaS3 YiMEGiJjh77kRa2m/4PIkXu5BLUtvx9PWOTRXGBxgqRFFbGsJzPjc8IPQROCfLFG2m78XbahWsM /IlpRRcTBU+CCxxDup4aWp5oOCIcIXJ29Vrn/aLKr6CxgpCiVuKtS8Qbp6aPjyuNSu1qAC/EFuY tv7AyxU5lmTer/HKsKShnya5NXloYXN7lf0Zg+4xJeJpYTmUtB7xlvjCTqfTgRPW/Pcv6HiiX4R DcX0PKTGrhyPNrZ05P5/+7I71ZZztJcKbr/LYtN4Y94hNzo+SdRbUM3O86is5QivqNkyroKIylB Qh3gOFf+8kI39oyexi2PKbRL3JZZ+8Ksg5WGwpkQHG2ymc3WSOtx27jWglbkU6JP+lYZZQM4iLM iQI/4jhV4HqNVQem3QCB65Y9yhYFk/wmDA242OqwFSrJm2aIjB1yaKcnmBgQ== X-Received: by 2002:a05:622a:350:b0:51c:555:7dea with SMTP id d75a77b69052e-5213cbd667cmr215415981cf.30.1784728136109; Wed, 22 Jul 2026 06:48:56 -0700 (PDT) Received: from gourry-fedora-PF4VCD3F (pool-173-79-60-52.washdc.fios.verizon.net. [173.79.60.52]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-907ba8e2581sm21393266d6.19.2026.07.22.06.48.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jul 2026 06:48:55 -0700 (PDT) Date: Wed, 22 Jul 2026 09:48:50 -0400 From: Gregory Price To: Richard Cheng Cc: linux-mm@kvack.org, Zhigang.Luo@amd.com, arun.george@samsung.com, balbirs@nvidia.com, brendan.jackman@linux.dev, yuzenghui@huawei.com, apopple@nvidia.com, alucerop@amd.com, matthew.brost@intel.com, akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, corbet@lwn.net, skhan@linuxfoundation.org, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, djbw@kernel.org, vishal.l.verma@intel.com, dave.jiang@intel.com, alison.schofield@intel.com, osandov@osandov.com, jannh@google.com, pfalcato@suse.de, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, pbonzini@redhat.com, osalvador@suse.de, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, kasong@tencent.com, qi.zheng@linux.dev, shakeel.butt@linux.dev, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, yury.norov@gmail.com, linux@rasmusvillemoes.dk, longman@redhat.com, ridong.chen@linux.dev, tj@kernel.org, mkoutny@suse.com, sj@kernel.org, jgg@ziepe.ca, jhubbard@nvidia.com, peterx@redhat.com, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, lance.yang@linux.dev, usama.arif@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, roman.gushchin@linux.dev, muchun.song@linux.dev, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, driver-core@lists.linux.dev, nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, linux-debuggers@vger.kernel.org, linux-fsdevel@vger.kernel.org, kvm@vger.kernel.org, cgroups@vger.kernel.org, damon@lists.linux.dev, linux-kselftest@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH v5 26/36] mm: add NODE_PRIVATE_CAP_RECLAIM for opted-in private node reclaim Message-ID: References: <20260720193431.3841992-1-gourry@gourry.net> <20260720193431.3841992-27-gourry@gourry.net> Precedence: bulk X-Mailing-List: cgroups@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: On Wed, Jul 22, 2026 at 09:36:14PM +0800, Richard Cheng wrote: > On Mon, Jul 20, 2026 at 03:34:20PM +0800, Gregory Price wrote: > > +static struct zonelist *memcg_reclaim_zonelist(int nid, gfp_t gfp_mask) > > +{ > > + unsigned int aflags = ALLOC_DEFAULT; > > + > > + if (unlikely(!nodes_empty(node_states[N_MEMORY_PRIVATE]))) > > + aflags = ALLOC_ZONELIST_PRIVATE; > > + > > + return select_zonelist(nid, gfp_mask, aflags); > > +} > > > I applied this code change and notice in mem_cgroup_shrink_node(), it calls > shrink_lruvec() directly and never passes through shrink_node(). > > This patch makes private nodes reachable through memcg reclaim zonelist, but > what prevents the direct per-node memcg path from reclaiming a private node > that has not set NODE_PRIVATE_CAP_RECLAIM ? > I legitimately missed this. Sashiko also picked it up on the filter patch: https://sashiko.dev/#/message/20260721183528.B4B9C1F00A3A%40smtp.kernel.org If nothing else - implementing this feature has taught me some sub-components of mm/ have very well centralized logic, and others (like vmscan.c) have 3 or 4 different paths in with a lot of strange quirks carved out. I think some of the vmscan paths can be improved to simplify this interaction, but i will fix this particular miss in v6 and come back around to see whether we can clean up these different paths as a general improvement. ~Gregory