From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A1AB343886; Wed, 20 May 2026 06:01:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779256889; cv=none; b=Yi+eOc4yVHqgXIov5n6EdJ4bO1PxktPwggVjEZaIvHRaiVqAq5phiqVxMpOVcq2czqnuRfQI+IB/LoLnvDZ8Op1u6C1PTltXWujjYWRWiL19sp5PbGwvVLb4INwuYsUEVKZe/BDSxyRKG29gJCFN1+xgcXRLwYX/rWwxQOC14Ec= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779256889; c=relaxed/simple; bh=M5foHdb6UyldcI/TMUxqynUvhWzgDhdlRXyTGuDw4/0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=eDVmKokTuoZRkkhTJ11j2pwZdXNzq1iUaV6N88yytIUMN7JGqGoGfKHC3LdkWekt0MzMWFVr6YNn10LxhSLCWtR1w6vAAv7MNZvCk31wvd1YG0k8Gn3ndOe5y0LMThXtMNn87yg4UT4is2bOs6A3QkZaL+9YKAioM2Ly0BWpaXo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=TC03oqID; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="TC03oqID" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4DD1D1F000E9; Wed, 20 May 2026 06:01:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779256888; bh=XUuf3KluThhkKceNz3An+1YHqbDqW0wLJBxqsVqxkwM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; 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 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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