From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31B15ECAAD5 for ; Mon, 5 Sep 2022 03:41:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236085AbiIEDlr (ORCPT ); Sun, 4 Sep 2022 23:41:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36366 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236060AbiIEDlm (ORCPT ); Sun, 4 Sep 2022 23:41:42 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCE9C2E695 for ; Sun, 4 Sep 2022 20:41:40 -0700 (PDT) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.53]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4MLZ5Z45HbzrS77; Mon, 5 Sep 2022 11:39:46 +0800 (CST) Received: from [10.67.102.169] (10.67.102.169) by canpemm500009.china.huawei.com (7.192.105.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 5 Sep 2022 11:41:38 +0800 CC: , , , , , , <21cnbao@gmail.com>, , , Subject: Re: [PATCH v2] arch_topology: Make cluster topology span at least SMT CPUs To: Greg KH References: <20220825092007.8129-1-yangyicong@huawei.com> From: Yicong Yang Message-ID: Date: Mon, 5 Sep 2022 11:41:38 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.102.169] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To canpemm500009.china.huawei.com (7.192.105.203) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/9/3 14:00, Greg KH wrote: > On Thu, Aug 25, 2022 at 05:20:07PM +0800, Yicong Yang wrote: >> From: Yicong Yang >> >> Currently cpu_clustergroup_mask() will return CPU mask if cluster span more >> or the same CPUs as cpu_coregroup_mask(). This will result topology borken >> on non-Cluster SMT machines when building with CONFIG_SCHED_CLUSTER=y. >> >> Test with: >> qemu-system-aarch64 -enable-kvm -machine virt \ >> -net none \ >> -cpu host \ >> -bios ./QEMU_EFI.fd \ >> -m 2G \ >> -smp 48,sockets=2,cores=12,threads=2 \ >> -kernel $Image \ >> -initrd $Rootfs \ >> -nographic \ >> -append "rdinit=init console=ttyAMA0 sched_verbose loglevel=8" >> >> We'll get below error: >> [ 3.084568] BUG: arch topology borken >> [ 3.084570] the SMT domain not a subset of the CLS domain >> >> Since cluster is a level higher than SMT, fix this by making cluster >> spans at least SMT CPUs. >> >> Cc: Sudeep Holla >> Cc: Vincent Guittot >> Cc: Ionela Voinescu >> Fixes: bfcc4397435d ("arch_topology: Limit span of cpu_clustergroup_mask()") >> Signed-off-by: Yicong Yang >> Reviewed-by: Sudeep Holla >> Reviewed-by: Ionela Voinescu >> --- >> Change since v1: >> - mention the kernel config CONFIG_SCHED_CLUSTER=y, per Ionela >> Link:https://lore.kernel.org/lkml/20220823073044.58697-1-yangyicong@huawei.com/ >> >> drivers/base/arch_topology.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c >> index 0424b59b695e..0056a1273275 100644 >> --- a/drivers/base/arch_topology.c >> +++ b/drivers/base/arch_topology.c >> @@ -724,7 +724,7 @@ const struct cpumask *cpu_clustergroup_mask(int cpu) >> */ >> if (cpumask_subset(cpu_coregroup_mask(cpu), >> &cpu_topology[cpu].cluster_sibling)) >> - return get_cpu_mask(cpu); >> + return cpu_smt_mask(cpu); > > As the kernel-test robot reported, this breaks the build on some > architectures, so I'll go and revert it from my tree now. > Sorry for the regression. The build error is because cpu_smt_mask() is defined only when CONFIG_SCHED_SMT=y so we'll fail when CONFIG_SCHED_SMT=n. Should use topology_sibling_cpumask() to get SMT mask here. Will respin this. Thanks.