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[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: linux-doc@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