From patchwork Mon Jun 27 16:50:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sudeep Holla X-Patchwork-Id: 12896909 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E85B4C433EF for ; Mon, 27 Jun 2022 16:56:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=R15p9Hhed/e0Gw3SbsZkiLiHszIVSWpCsW7Zz5X7KXM=; b=Gv6u7f6PNAMS/f XXYApNi4z2+ZA16wxWAyZUl8z2U+XeMvvMBef8NV6v31arKIESBbVTdrLm6hi/verEn0KHBuogxLm cqz+adBlYekquYBKfsRI7Qso+j64ZbhGh76rY1M2r4xk5kAN6f7Mpc6JUpze8qTcZcgAsVGWTKflK rw/CCGIiaFl1lSfUU8JGuNW3rTzaYSf0M5S3GnbjOn57WxSON/D/Pv63h/696YSjDPLbFEI61GYYh 0jh4yl2nX90mpSYZwkqBIBfcamI+DyRtwgOLUsNgcC7gwBD4o7SkL3Ew0Li+htIRf52uDCRYVv9am Db0SrmKQ8XwMhgF6DjfA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o5s2N-001xM5-Hv; Mon, 27 Jun 2022 16:56:35 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o5rxS-001uH1-HD; Mon, 27 Jun 2022 16:51:32 +0000 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220627_095130_679224_11577F06 X-CRM114-Status: GOOD ( 11.65 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.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 Acked-by: Vincent Guittot --- 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; }