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 X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48B09C432C0 for ; Wed, 20 Nov 2019 11:09:28 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 1AAC122365 for ; Wed, 20 Nov 2019 11:09:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="OHYgn/G7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1AAC122365 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=onXOF7+sMWXQUK3kVkz0oiMwQtB+8qdvBmYiHg2DReg=; b=OHYgn/G7j1+kGI Z34tAZhsfw3jNTmrMk/0e1CAmkzv5WT8v8/tD1Tv9hBHA3V63FXXrke+Lyf8CgpRAz0EHQKdRewFj JAVcr/YCDX7waMZJpz6jZq+a+FY0Y9kRfv6Pmm8ca4B8uNOjr967EpXEt4TcCKnW9uK3ko2bEKn/H CCpWiI1duttWk7sdv3hrrPEI+NEB/nKnxN+TvaiNysfUVfRCupKPdlsP2JiJLBaW/v9dO0/KTq8Vi fmarikr+AeWTYqom8OwsZEKMclX/nZoDv6lX69hMm8Bg2RW3L/Yc9/FqVbd1XqNOftzz6xrXEHkWQ 4dGmRRLgIrkDryGEj7pQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iXNrT-0004li-GD; Wed, 20 Nov 2019 11:09:27 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iXNrQ-0004kq-O6 for linux-arm-kernel@lists.infradead.org; Wed, 20 Nov 2019 11:09:26 +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 4AEDE31B; Wed, 20 Nov 2019 03:09:22 -0800 (PST) Received: from bogus (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2F7273F6C4; Wed, 20 Nov 2019 03:09:21 -0800 (PST) Date: Wed, 20 Nov 2019 11:09:11 +0000 From: Sudeep Holla To: Dietmar Eggemann Subject: Re: [PATCH] arm: Fix topology setup in case of CPU hotplug for CONFIG_SCHED_MC Message-ID: <20191120110911.GA31600@bogus> References: <20191120104212.14791-1-dietmar.eggemann@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191120104212.14791-1-dietmar.eggemann@arm.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191120_030924_875447_CB24B06D X-CRM114-Status: GOOD ( 22.58 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, Russell King , Atish Patra , Lukasz Luba , Sudeep Holla , Morten Rasmussen , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Dietmar, Lukasz, Thanks for digging this bug and fixing it. On Wed, Nov 20, 2019 at 10:42:12AM +0000, Dietmar Eggemann wrote: > Commit ca74b316df96 ("arm: Use common cpu_topology structure and > functions.") changed cpu_coregroup_mask() from the ARM32 specific > implementation in arch/arm/include/asm/topology.h to the one shared > with ARM64 and RISCV in drivers/base/arch_topology.c. > > Currently on Arm32 (TC2 w/ CONFIG_SCHED_MC) the task scheduler setup > code (w/ CONFIG_SCHED_DEBUG) shows this during CPU hotplug: > > ERROR: groups don't span domain->span > > It happens to CPUs of the cluster of the CPU which gets hot-plugged > out on scheduler domain MC. > > Turns out that the shared cpu_coregroup_mask() requires that the > hot-plugged CPU is removed from the core_sibling mask via > remove_cpu_topology(). Otherwise the 'is core_sibling subset of > cpumask_of_node()' doesn't work. In this case the task scheduler has to > deal with cpumask_of_node instead of core_sibling which is wrong on > scheduler domain MC. > > e.g. CPU3 hot-plugged out on TC2 [cluster0: 0,3-4 cluster1: 1-2]: > > cpu_coregroup_mask(): CPU3 cpumask_of_node=0-2,4 core_sibling=0,3-4 > ^ > should be: > > cpu_coregroup_mask(): CPU3 cpumask_of_node=0-2,4 core_sibling=0,4 > > Add remove_cpu_topology() to __cpu_disable() to remove the CPU from the > topology masks in case of a CPU hotplug out operation. > > At the same time tweak store_cpu_topology() slightly so it will call > update_siblings_masks() in case of CPU hotplug in operation via > secondary_start_kernel()->smp_store_cpu_info(). > > This aligns the Arm32 implementation with the Arm64 one. > > Fixes: ca74b316df96 ("arm: Use common cpu_topology structure and functions") Apart from the minor nit below, Reviewed-by: Sudeep Holla > Signed-off-by: Dietmar Eggemann > --- > arch/arm/kernel/smp.c | 2 ++ > arch/arm/kernel/topology.c | 15 +++++++-------- > 2 files changed, 9 insertions(+), 8 deletions(-) > > diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c > index 4b0bab2607e4..139c0d98fa29 100644 > --- a/arch/arm/kernel/smp.c > +++ b/arch/arm/kernel/smp.c > @@ -240,6 +240,8 @@ int __cpu_disable(void) > if (ret) > return ret; > > + remove_cpu_topology(cpu); > + > /* > * Take this CPU offline. Once we clear this, we can't return, > * and we must not schedule until we're ready to give up the cpu. > diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c > index 5b9faba03afb..b37b0a340991 100644 > --- a/arch/arm/kernel/topology.c > +++ b/arch/arm/kernel/topology.c > @@ -196,9 +196,8 @@ void store_cpu_topology(unsigned int cpuid) > struct cpu_topology *cpuid_topo = &cpu_topology[cpuid]; > unsigned int mpidr; > > - /* If the cpu topology has been already set, just return */ > - if (cpuid_topo->core_id != -1) > - return; > + if (cpuid_topo->package_id != -1) > + goto topology_populated; > > mpidr = read_cpuid_mpidr(); > > @@ -231,14 +230,14 @@ void store_cpu_topology(unsigned int cpuid) > cpuid_topo->package_id = -1; > } > > - update_siblings_masks(cpuid); > - > update_cpu_capacity(cpuid); > > pr_info("CPU%u: thread %d, cpu %d, socket %d, mpidr %x\n", > - cpuid, cpu_topology[cpuid].thread_id, > - cpu_topology[cpuid].core_id, > - cpu_topology[cpuid].package_id, mpidr); > + cpuid, cpuid_topo->thread_id, cpuid_topo->core_id, > + cpuid_topo->package_id, mpidr); > + [nit] The above is a clearly cosmetic cleanup and shouldn't be part of this fix as they will be backported automatically. So I prefer to drop this or make it separate patch if required. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel