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b=0OwOF5GRKu1XM8PCJmtJm7JwwRhQ+5OfsLLDyZ/GlFRiyRAV8do+q5Vwxrmz3T/xa 5ZYDxWowFGupNj8IxGUa0dbSBDxGjyOcbb013O6cd79XD5RrhMX2CdtrnNTCN2fr3e VpiC1xdVqc5nG9LPkG+e6QIebyn0iikxJ2xUoxWA= Date: Sat, 3 May 2025 20:03:34 -0700 From: Andrew Morton To: Oscar Salvador Cc: David Hildenbrand , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vlastimil Babka , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Jonathan Cameron , Rakie Kim Subject: Re: [PATCH v3 0/3] Implement numa node notifier Message-Id: <20250503200334.3f912eeb7ca484bca4eec7fd@linux-foundation.org> In-Reply-To: <20250502083624.49849-1-osalvador@suse.de> References: <20250502083624.49849-1-osalvador@suse.de> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 424A880007 X-Stat-Signature: 8tra36z98fch9ugykhb8nu7e68qotuud X-Rspam-User: X-HE-Tag: 1746327816-243122 X-HE-Meta: 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 uSMehj5I OA2pGjQKGUUlQhASlEwby7JaZEO0Vu1fwaKZu0/VUBnHwIWOfM4HQWQLasWGwNbt1yt6QnniBcxBRVzrvHF/eFkv1U0UxGz1F7fthjpRvaJq2J5gem1UXKU6jslAgDGExlHAS2FLQqa6Y3vJMZ+6WNGS2ghc7XNISEZSg2/rM9FS3PiE+k+Gl0s8VC2bv4vqlSbjjZKA7UkR+Fkfbbt3QX/ysAPPZKqHagTLVUBxfjfX0/5E+hGDMXV3FTaacn0VXlRVinjr46fT1nIHXZRWPJKdBM9b+4j3izFO00LR8PX5K0oZyYDSHxMHwiBIIZUwqFOiD 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 Fri, 2 May 2025 10:36:21 +0200 Oscar Salvador wrote: > Memory notifier is a tool that allow consumers to get notified whenever > memory gets onlined or offlined in the system. > Currently, there are 10 consumers of that, but 5 out of those 10 consumers > are only interested in getting notifications when a numa node changes its > memory state. > That means going from memoryless to memory-aware of vice versa. > > Which means that for every {online,offline}_pages operation they get > notified even though the numa node might not have changed its state. Why is this a problem? Is there some bug? Are these notifications so frequent that there are significant inefficiencies here? Further down-thread, Gregory tells us that Dan's patch "seems to fix the underlying problem", but nobody (including Dan) told us about any "problem" at all.