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b=TC03oqIDpmgQKcVjw9nJ0KNPdkGUZuF7PCpEoA+pJfAToPjhihGccVLPtvrebIZbH q61MwlIfLoTojg6kBoO1Y9KD8qpDHC/I3K6mMlo7bzwPliW+QDgrn4tmSnyyffr3Qk GOTGOaZ+RdS0NOhXhoUaT681o+mAUSZUWISGAMN+GsYzAcaBN+PBd/deu/ItbHXNB1 GYdF8v4jC9wB8nkjjzc7AeGevyKJsQBaPrGET0L14S/ae98BQZlVBr5cEH1Gcp4MtJ ZJYfPYWE0ZTKsC2DYcdAG7T+ZK4uovuYIkaNpNOugb9GRyRcIIbU0q4q0JrN2dW7xI uTmhrtZcP2C9g== Message-ID: <00a65776-ce8f-49ad-8fe3-797d6e92f51a@kernel.org> Date: Wed, 20 May 2026 15:01:23 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] memcg: store node_id instead of pglist_data pointer To: Shakeel Butt , Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Muchun Song , Qi Zheng , Alexandre Ghiti , Joshua Hahn , Meta kernel team , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel test robot References: <20260520053123.2709959-1-shakeel.butt@linux.dev> <20260520053123.2709959-2-shakeel.butt@linux.dev> Content-Language: en-US From: Harry Yoo In-Reply-To: <20260520053123.2709959-2-shakeel.butt@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 2F8654000E X-Rspam-User: X-Stat-Signature: rj3p6ah5cb8sqbecnrsqgqm36gzrjk3k X-HE-Tag: 1779256889-533697 X-HE-Meta: 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 vudaB4wL rkFECQZ3usoZYMgMKWfnV/yVwx9ZlQN0tqfETVrfDCKWnEwyoqJpvIMA1HIkgrH2/5Lx2IE59aMGNZOAQyR3AZ6D1E2c0EJojuFYag3tE8YSPWI8/NeB+z8UaNoXah9sysN7HfJYEBLv2eSaV/ADIivBBok88Ut9OM1x4UtMEiouBBWAr3SFcr1tQWTyoNpDOhRQIU0zyngSM77PELZBSynP3Sgi1gG1NYMbRxmVLj9zwaAdjn3ai78/w6p2ZvckV0HLkvw9/3i89/5nzUnzCUzn6/h5BWjXerStTj9zzxz7Ifjmpo9K3XkTzAiILuobd2nSnHvgmbnsxUoeAOq35ABh/ZBM+ym6/CcRSRhVfX7yEjLiGmyTn4U/UzGokwWNuZYjFDtK+3Xa5Tr5UFXQ5qdT4CFn1HgzZW6squDoLXFQDvsk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/20/26 2:31 PM, Shakeel Butt wrote: > The struct obj_stock_pcp stores a pointer to pglist_data for the slab > stats cached on the cpu. On 64-bit machines, this costs 8 bytes. The > pointer is not strictly required: NODE_DATA() can recover it from the > node id. Replace cached_pgdat with int16_t node_id and use NUMA_NO_NODE > as the "no stats cached" sentinel. > > At the moment all the archs limit MAX_NUMNODES to 1024 so int16_t is > plenty; a BUILD_BUG_ON() makes sure we notice if that ever changes. > > Signed-off-by: Shakeel Butt > Tested-by: kernel test robot > --- Reviewed-by: Harry Yoo (Oracle) -- Cheers, Harry / Hyeonggon