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Mon, 16 Feb 2026 09:50:30 -0800 (PST) Received: from [192.168.4.196] ([73.222.117.172]) by smtp.gmail.com with ESMTPSA id 5a478bee46e88-2bacb66c24esm10455308eec.27.2026.02.16.09.50.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 16 Feb 2026 09:50:30 -0800 (PST) Message-ID: <3fe7c5dd-b184-4421-a21c-bafce6aa7b09@gmail.com> Date: Mon, 16 Feb 2026 09:50:26 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] mm/mempolicy: track page allocations per mempolicy To: Michal Hocko Cc: linux-mm@kvack.org, apopple@nvidia.com, akpm@linux-foundation.org, axelrasmussen@google.com, byungchul@sk.com, cgroups@vger.kernel.org, david@kernel.org, eperezma@redhat.com, gourry@gourry.net, jasowang@redhat.com, hannes@cmpxchg.org, joshua.hahnjy@gmail.com, Liam.Howlett@oracle.com, linux-kernel@vger.kernel.org, lorenzo.stoakes@oracle.com, matthew.brost@intel.com, mst@redhat.com, rppt@kernel.org, muchun.song@linux.dev, zhengqi.arch@bytedance.com, rakie.kim@sk.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, surenb@google.com, virtualization@lists.linux.dev, vbabka@suse.cz, weixugc@google.com, xuanzhuo@linux.alibaba.com, ying.huang@linux.alibaba.com, yuanchu@google.com, ziy@nvidia.com, kernel-team@meta.com References: <20260212045109.255391-1-inwardvessel@gmail.com> <20260212045109.255391-2-inwardvessel@gmail.com> Content-Language: en-US From: "JP Kobryn (Meta)" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Stat-Signature: fpdr6efxqpcb5kgzwbjd9x8gs3g6s84k X-Rspamd-Queue-Id: 69883140008 X-Rspam-User: X-HE-Tag: 1771264232-718045 X-HE-Meta: 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 5o9eOpxF 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 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 2/16/26 12:26 AM, Michal Hocko wrote: > On Thu 12-02-26 13:22:56, JP Kobryn wrote: >> On 2/11/26 11:29 PM, Michal Hocko wrote: >>> On Wed 11-02-26 20:51:08, JP Kobryn wrote: >>>> It would be useful to see a breakdown of allocations to understand which >>>> NUMA policies are driving them. For example, when investigating memory >>>> pressure, having policy-specific counts could show that allocations were >>>> bound to the affected node (via MPOL_BIND). >>>> >>>> Add per-policy page allocation counters as new node stat items. These >>>> counters can provide correlation between a mempolicy and pressure on a >>>> given node. >>> >>> Could you be more specific how exactly do you plan to use those >>> counters? >> >> Yes. Patch 2 allows us to find which nodes are undergoing reclaim. Once >> we identify the affected node(s), the new mpol counters (this patch) >> allow us correlate the pressure to the mempolicy driving it. > > I would appreciate somehow more specificity. You are adding counters > that are not really easy to drop once they are in. Sure we have > precedence of dropping some counters in the past so this is not as hard > as usual userspace APIs but still... > > How exactly do you tolerate mempolicy allocations to specific nodes? > While MPOL_MBIND is quite straightforward others are less so. The design does account for this regardless of the policy. In the call to __mod_node_page_state(), I'm using page_pgdat(page) so the stat is attributed to the node where the page actually landed.