From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (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 33B2C225A35; Thu, 8 Jan 2026 15:47:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767887268; cv=none; b=oiFRvzBPISH3m0IbEOGz9855yrR/0+KgciIJxH9AwphJWQt/El7WrmRpbuSPZ1zy+vN6UbzyPbMozpvsMGFQcHDCzwH4g70Oj1B4p3JWqINGT0FkJCW7FnznCdlVSgRNPuPqfn5cMKWXNbxbvpbvf4n5OESvimQS/vXABlrThb8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767887268; c=relaxed/simple; bh=eXw8s/TXZ4Wv5IRw/ODhDXJ23117Q7X4/ZFRfDehaj4=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=OfslB2R4WT/VVy/xq2ugZNoERHXvv7hVJEx+28GyeJKDoOUqLv+6qQ/VF6w9oMhugbXZkiIfIc46ALosSWYPkJQC396qVUWwHcOCa1X5GfW9/08XwHf8YD3EFLbpIR249hwT4abypL5i1waneHLE2jznr7+IlWkz6aPrI5I5Zvo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.224.150]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4dn8Rn1V78zHnGjb; Thu, 8 Jan 2026 23:47:33 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id 8DFFA40563; Thu, 8 Jan 2026 23:47:41 +0800 (CST) Received: from localhost (10.203.177.15) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Thu, 8 Jan 2026 15:47:40 +0000 Date: Thu, 8 Jan 2026 15:47:38 +0000 From: Jonathan Cameron To: Akinobu Mita CC: , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v3 1/3] mm: memory-tiers, numa_emu: enable to create memory tiers using fake numa nodes Message-ID: <20260108154738.00000e47@huawei.com> In-Reply-To: <20260108101535.50696-2-akinobu.mita@gmail.com> References: <20260108101535.50696-1-akinobu.mita@gmail.com> <20260108101535.50696-2-akinobu.mita@gmail.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: lhrpeml100011.china.huawei.com (7.191.174.247) To dubpeml100005.china.huawei.com (7.214.146.113) On Thu, 8 Jan 2026 19:15:33 +0900 Akinobu Mita wrote: > This makes it possible to create memory tiers using fake numa nodes > generated by numa emulation. > > The "numa_emulation.adistance=" kernel cmdline option allows you to set > the abstract distance for each NUMA node. > > For example, you can create two fake nodes, each in a different memory > tier by booting with "numa=fake=2 numa_emulation.adistance=576,704". > Here, the abstract distances of node0 and node1 are set to 576 and 706, > respectively. > > Each memory tier covers an abstract distance chunk size of 128. Thus, > nodes with abstract distances between 512 and 639 are classified into the > same memory tier, and nodes with abstract distances between 640 and 767 > are classified into the next slower memory tier. > > The abstract distance of fake nodes not specified in the parameter will > be the default DRAM abstract distance of 576. > > Signed-off-by: Akinobu Mita > --- > v2: > - fix the explanation about cmdline parameter in the commit log A couple of comments on includes, with those resolved LGTM. Reviewed-by: Jonathan Cameron > > mm/numa_emulation.c | 26 ++++++++++++++++++++++++++ > 1 file changed, 26 insertions(+) > > diff --git a/mm/numa_emulation.c b/mm/numa_emulation.c > index 703c8fa05048..a4266da21344 100644 > --- a/mm/numa_emulation.c > +++ b/mm/numa_emulation.c > @@ -6,6 +6,9 @@ > #include > #include > #include > +#include > +#include > +#include I can't immediately spot why the new code needs node.h Should also include linux/notifier.h for the notifier_block definition. > #include > #include > #include > @@ -344,6 +347,27 @@ static int __init setup_emu2phys_nid(int *dfl_phys_nid) > return max_emu_nid; > } > > +static int adistance[MAX_NUMNODES]; > +module_param_array(adistance, int, NULL, 0400); > +MODULE_PARM_DESC(adistance, "Abstract distance values for each NUMA node"); > + > +static int emu_calculate_adistance(struct notifier_block *self, > + unsigned long nid, void *data) > +{ > + if (adistance[nid]) { > + int *adist = data; > + > + *adist = adistance[nid]; > + return NOTIFY_STOP; > + } > + return NOTIFY_OK; > +} > + > +static struct notifier_block emu_adist_nb = { > + .notifier_call = emu_calculate_adistance, > + .priority = INT_MIN, > +}; > + > /** > * numa_emulation - Emulate NUMA nodes > * @numa_meminfo: NUMA configuration to massage > @@ -532,6 +556,8 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt) > } > } > > + register_mt_adistance_algorithm(&emu_adist_nb); > + > /* free the copied physical distance table */ > memblock_free(phys_dist, phys_size); > return;