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Sun, 16 Aug 2026 21:52:27 -0700 (PDT) From: Joshua Hahn To: Gregory Price Cc: Rakie Kim , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, nvdimm@lists.linux.dev, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, dave@stgolabs.net, jic23@kernel.org, dave.jiang@intel.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, harry@kernel.org, kernel_team@skhynix.com, honggyu.kim@sk.com, yunjeong.mun@sk.com Subject: Re: [PATCH 0/4] mm/mempolicy: introduce package-aware weighted interleave Date: Sun, 16 Aug 2026 21:52:24 -0700 Message-ID: <20260817045225.1807518-1-joshua.hahnjy@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Sun, 16 Aug 2026 20:46:16 -0400 Gregory Price wrote: > On Thu, Aug 13, 2026 at 03:23:48PM +0900, Rakie Kim wrote: > > On Wed, 12 Aug 2026 22:37:06 -0400 Gregory Price wrote: > > > > The cpuset.mems = 0,2 you describe is the node set of package 0, so > > the tasks in that cgroup use node0 and node2 wherever they run. > > > > I think you are over-complicating the explanation and that's making it > hard for folks to reason about this. > > My best understanding here is for multi-socket systems, weighted > interleave as-designed is inherently sub-optimal for scaled workloads > that utilize multi-socket ("package") memory resources (DRAM, CXL...) I was thinking about this and I think Gregory is right here. I wonder how much of the framing around this series can be preserved / simplified if we just say "prevent tasks from allocating memory cross-socket". I also wonder if instead of limiting this to weighted interleave, this can sit on top of other mpols and just nodemasks against cross-socket nodes. > I think there is also an assumption that total memory utilization is > less than the total capacity - otherwise some of the assumptions here > break, but that comes with the general weighted interleave story. > > I'm getting back from vacation, I will take a closer look this week. I am also out on vacation this week : -) I'll take a closer look along with the code next week as well. Thanks, Rakie and Gregory! Joshua