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[173.79.60.52]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8cecd06e4d6sm231860136d6.36.2026.06.10.03.41.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Jun 2026 03:41:59 -0700 (PDT) Date: Wed, 10 Jun 2026 06:41:57 -0400 From: Gregory Price To: Balbir Singh Cc: lsf-pc@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, damon@lists.linux.dev, kernel-team@meta.com, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, dave@stgolabs.net, jonathan.cameron@huawei.com, dave.jiang@intel.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, dan.j.williams@intel.com, longman@redhat.com, akpm@linux-foundation.org, david@kernel.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, osalvador@suse.de, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, yury.norov@gmail.com, linux@rasmusvillemoes.dk, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com, jackmanb@google.com, sj@kernel.org, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, muchun.song@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, jannh@google.com, linmiaohe@huawei.com, nao.horiguchi@gmail.com, pfalcato@suse.de, rientjes@google.com, shakeel.butt@linux.dev, riel@surriel.com, harry.yoo@oracle.com, cl@gentwo.org, roman.gushchin@linux.dev, chrisl@kernel.org, kasong@tencent.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, zhengqi.arch@bytedance.com, terry.bowman@amd.com Subject: Re: [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) Message-ID: References: <20260222084842.1824063-1-gourry@gourry.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 0B118A0005 X-Rspam-User: X-Stat-Signature: hdwg75d9puptaui4n37ri1i7qutx5msi X-HE-Tag: 1781088121-24168 X-HE-Meta: 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 mVg+dxYz BzQRF60tQFbni6kDWKB9LE0PADJDi7hlSwr94R+ZLXZnTCpVTvxph3Cgbbfa4mTYZaehopULPVY73h2pon4sG6aPd/CgleuAuPbwOG4Kv8sMjRCq2k/O6S4B8hgvGcK9bHWDZsd3LaUI7JCrZBfwURkx7KgSh7ZURtTd/aygfXlCYMDKhlWrzmhBUi344FNagJ1/3EXLvns1AXqan0D1YfgxTJrz6nJeKNcNUVCg1jtqZUuzHg/NJd3F5WXepieifBPXEmF9RtdC1wtU0xNZhwLQhHWtkxEWiPqHAljCWArDqukoYH40sbmp9sC+I4XrSNpJJ73IEoyvwdzhOgv1kpUyVquK/uJ2L3Yg0ZHLsGFcCSqOE5pvur5vy3gsbCARo5un7YLSbKSbPBI1WdK9L+biR9A== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jun 03, 2026 at 03:00:01PM +1000, Balbir Singh wrote: > > > > __GFP_THISNODE cannot be overloaded to do anything useful here. > > Let me clarify, I meant to say, let's use a nodemask for allocation > and __GFP_THISNODE gets us to the node we desire, if that is the only > node. My earlier comment might not have been clear. > I've been tested an stripped back patch set where I drop all FALLBACK entries for private nodes (including for itself) and only keep the NOFALLBACK entry for private nodes. This effectively isolates the nodes for any allocation without __GFP_THISNODE. This also precludes these nodes from ever using non-mbind mempolicies, which I think is a completely reasonable compromise and something I was already expecting we would do. Notably: slub.c injects __GFP_THISNODE internally on behalf of kmalloc, which causes spillage into private nodes because slub allows private nodes in its mask. I think this is fixable. I have to inspect some other __GFP_THISNODE users (hugetlb, some arch code, etc), but it seems like fully dropping the FALLBACK entries and requiring __GFP_THISNODE might be sufficient. ~Gregory