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Received: from DESKTOP-5N7EMDA(mailfrom:ying.huang@linux.alibaba.com fp:SMTPD_---0X6.LgeD_1782818452 cluster:ay36) by smtp.aliyun-inc.com; Tue, 30 Jun 2026 19:21:22 +0800 From: "Huang, Ying" To: Gregory Price Cc: Johannes Weiner , Andrew Morton , David Hildenbrand , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Alistair Popple , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Neha Gholkar Subject: Re: [PATCH] mm: mempolicy: fix automatic numa balancing for shmem In-Reply-To: (Gregory Price's message of "Mon, 29 Jun 2026 13:59:41 -0400") References: <20260629163337.1264881-1-hannes@cmpxchg.org> Date: Tue, 30 Jun 2026 19:20:50 +0800 Message-ID: <87h5mkz33h.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: F045BA000D X-Rspam-User: X-Stat-Signature: qfj96ofwxzrztbtanargckm6uef8bqom X-HE-Tag: 1782818486-918329 X-HE-Meta: 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 YLv+P6Pu ybISQOkL+ejEb8wu5ADw8hPjWb6mp4SF/TjyeNSNEwLbiPHoBcEOnTo+k7ZE+A9NPUvYIFPUPmbofElVmD1gaMTfr8DvYv9keHRZ3A+iT0Tmru20atQXOIYb+5iCPbD8jb7pjGG0nOkgNI95rQlrtC5weIHIEEYvJkKATK3Ha8y1vYNE2qLak4WRQLHhIoluxZFPcRnZdXSsJWT9aPWavwUcRj/yqATsQX40nYFMS+rpR/UyMn06oZOhwHd97NY+qedG2LltCjNcGg3jpws8ngrrchSC1SFlM9JDAqEroLmKJRubwWcfnI7jEC9d8or3vFSwUVYqNHWfi0E3Nn1LxU2awh4KDZTDas5cDZPJou+xabCkeM9JkBdJAGCITWUY38o2tVELKZLxFXrOuVS7l5szZdw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Gregory Price writes: [snip] > Demotions don't care about mempolicy, so opting shmem out of NUMA > balancing and mbind'ing on a tiered system is just full sadness. > > This is all just more evidence that demotion needs to be completely > redone, it's creating a mess of undefined behavior for memory placement. It's hard to respect mempolicy during demotion in the current implementation. Do you have any ideas on how to improve this? --- Best Regards, Huang, Ying