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 7587DC433EF for ; Mon, 27 Jun 2022 16:52:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239682AbiF0QwJ (ORCPT ); Mon, 27 Jun 2022 12:52:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239555AbiF0Qva (ORCPT ); Mon, 27 Jun 2022 12:51:30 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9D5E61114F for ; Mon, 27 Jun 2022 09:51:29 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A1434175A; Mon, 27 Jun 2022 09:51:29 -0700 (PDT) Received: from usa.arm.com (e103737-lin.cambridge.arm.com [10.1.197.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id A50543F792; Mon, 27 Jun 2022 09:51:27 -0700 (PDT) From: Sudeep Holla To: linux-kernel@vger.kernel.org Cc: Sudeep Holla , Greg Kroah-Hartman , Atish Patra , Atish Patra , Vincent Guittot , Dietmar Eggemann , Qing Wang , Rob Herring , "Rafael J . Wysocki" , Ionela Voinescu , Pierre Gondois , linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, Darren Hart Subject: [PATCH v5 16/19] arch_topology: Limit span of cpu_clustergroup_mask() Date: Mon, 27 Jun 2022 17:50:44 +0100 Message-Id: <20220627165047.336669-17-sudeep.holla@arm.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220627165047.336669-1-sudeep.holla@arm.com> References: <20220627165047.336669-1-sudeep.holla@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ionela Voinescu Currently the cluster identifier is not set on DT based platforms. The reset or default value is -1 for all the CPUs. Once we assign the cluster identifier values correctly, the cluster_sibling mask will be populated and returned by cpu_clustergroup_mask() to contribute in the creation of the CLS scheduling domain level, if SCHED_CLUSTER is enabled. To avoid topologies that will result in questionable or incorrect scheduling domains, impose restrictions regarding the span of clusters, as presented to scheduling domains building code: cluster_sibling should not span more or the same CPUs as cpu_coregroup_mask(). This is needed in order to obtain a strict separation between the MC and CLS levels, and maintain the same domains for existing platforms in the presence of CONFIG_SCHED_CLUSTER, where the new cluster information is redundant and irrelevant for the scheduler. While previously the scheduling domain builder code would have removed MC as redundant and kept CLS if SCHED_CLUSTER was enabled and the cpu_coregroup_mask() and cpu_clustergroup_mask() spanned the same CPUs, now CLS will be removed and MC kept. Link: https://lore.kernel.org/r/20220621192034.3332546-18-sudeep.holla@arm.com Cc: Darren Hart Tested-by: Ionela Voinescu Signed-off-by: Ionela Voinescu Signed-off-by: Sudeep Holla --- drivers/base/arch_topology.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 46fa1b70b02b..277b65cf3306 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -686,6 +686,14 @@ const struct cpumask *cpu_coregroup_mask(int cpu) const struct cpumask *cpu_clustergroup_mask(int cpu) { + /* + * Forbid cpu_clustergroup_mask() to span more or the same CPUs as + * cpu_coregroup_mask(). + */ + if (cpumask_subset(cpu_coregroup_mask(cpu), + &cpu_topology[cpu].cluster_sibling)) + return get_cpu_mask(cpu); + return &cpu_topology[cpu].cluster_sibling; } -- 2.36.1