From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-171.mta0.migadu.com (out-171.mta0.migadu.com [91.218.175.171]) (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 4ED4925B09F for ; Fri, 22 May 2026 02:27:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779416870; cv=none; b=BGaai08hAspdzBSLZvAbvDmC5eL7NepHfexZS9ZPQEXLd7Lyj9G82Zs0C+MSUYQJAYfy9jqAwwLdpcTzNCgbU3bpVuaqqldHGQ3lRTf56nRT0spJpl38Y9ZyQcszZlzGTkz0EdRN6wzhuHwv6Yq6KWKoUKnl8WGuEaRb/NOrLT8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779416870; c=relaxed/simple; bh=DhpVESDQBgXXw+wOLddAcOF5ND6kknaupEmYWCM3y00=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=dhv7Jl+Cl6D+1VoRQV37/A05eu3b46iQju7rEGTujWsxmepJqrkkvLI03uTBMJxZyWQ56s0P4tfl8eUne8His4DY0tVfMpaW5pUq7wY1xHkviPZsjKSWRGfDFuDnGE3AdQ34kDa91UU4XDwIb7X0R44O/FAk0d942K0QrW3FdEI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=GVpw4nkH; arc=none smtp.client-ip=91.218.175.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="GVpw4nkH" Message-ID: <150014a5-82d0-4e53-8595-b01b3bf43832@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1779416866; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uLflcTnDVR68YXOTUiaDyXVU/XHr7QC3203n7y7YGNA=; b=GVpw4nkHZflPEGjsfKYHrPnisj2uSGUz/jH04R8rFFS6qfVFmYVXCQ7eZNWVP+ct/UCMvM 5NytgX00z3Av116TkzeRk51G4La7vdHEP5NeWrdXXv+B0nOyKtG2JlNyKk3gv3e9QSn9V9 6YkanccAoChLgcmi7ZWHvgil1S7hpXs= Date: Fri, 22 May 2026 10:27:38 +0800 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v2 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 , Alexandre Ghiti , Joshua Hahn , Harry Yoo , Meta kernel team , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel test robot References: <20260522011908.1669332-1-shakeel.butt@linux.dev> <20260522011908.1669332-2-shakeel.butt@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Qi Zheng In-Reply-To: <20260522011908.1669332-2-shakeel.butt@linux.dev> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 5/22/26 9:19 AM, 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. > > Fixes: 01b9da291c49 ("mm: memcontrol: convert objcg to be per-memcg per-node type") > Tested-by: kernel test robot > Signed-off-by: Shakeel Butt > Acked-by: Muchun Song > Reviewed-by: Harry Yoo (Oracle) > --- > > Changes since v1: > - Added tags in the commit message > > mm/memcontrol.c | 26 +++++++++++++++++++------- > 1 file changed, 19 insertions(+), 7 deletions(-) > Acked-by: Qi Zheng Thanks!