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[109.81.81.105]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4317d03ee7asm47105805e9.0.2024.10.23.15.23.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Oct 2024 15:23:57 -0700 (PDT) Date: Thu, 24 Oct 2024 00:23:56 +0200 From: Michal Hocko To: Dongjoo Seo Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, dave@stgolabs.net, dan.j.williams@intel.com, nifan@outlook.com, a.manzanares@samsung.com Subject: Re: [PATCH] mm/page_alloc: fix NUMA stats update for cpu-less nodes Message-ID: References: <20241023175037.9125-1-dongjoo.linux.dev@gmail.com> <20241023134121.68d4af59e2d9cc3e78a34cc8@linux-foundation.org> 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: On Wed 23-10-24 15:15:20, Dongjoo Seo wrote: > Hi Andrew, Michal, > > Thanks for the feedback. > > The issue is that CPU-less nodes can lead to incorrect NUMA stats. > For example, NUMA_HIT may incorrectly increase for CPU-less nodes > because the current logic doesn't account for whether a node has CPUs. Define incorrect Current semantic doesn't really care about cpu less NUMA nodes because current means whatever is required AFIU. This is certainly a long term semantic. Why does this need to change and why it makes sense to pre-existing users? -- Michal Hocko SUSE Labs