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 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 E64B1C43334 for ; Thu, 14 Jul 2022 17:53:20 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc: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=NtOXV/jvqd++TLDb8JFfEJHSKkLb7qKgSZbA1f8IR9o=; b=zQguLiR2IBsdwE uRx81ebc3LNBS5m4/Bx8giLnS+8kC2kB12EHusRBilzjardIlbGaV/C+IqdqI8SBfan6leuSGoHUH bi7siaEpDh2qIuk/XDZknI3nfO1Tk3IbmCdZOJBERe6UaA/fHnqP9/9i+Fs3MAsC/DZJiKsBYLJ/7 YQNTfjrhjCI3B2QhZ79BK59JIbCSd8/rvgUQ7RMcWTv47gx5dpRJ+48eBKm4RweZqy3Gu0KnQr5h+ Ma6x1MICH7S1uBiPs0p7/9SN7vbQUGzXoRlMllTAFtePVpRUNQKcfqTEnQiumAUc9oPczjvAYpc6P iHniSnz51M0O0b/vIWBw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oC31Q-00Gtih-Qd; Thu, 14 Jul 2022 17:53:08 +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 1oC31F-00GtdQ-4i; Thu, 14 Jul 2022 17:52:58 +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 4062C1D13; Thu, 14 Jul 2022 10:52:52 -0700 (PDT) Received: from localhost (ionvoi01-desktop.cambridge.arm.com [10.1.196.65]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6883F3F70D; Thu, 14 Jul 2022 10:52:51 -0700 (PDT) Date: Thu, 14 Jul 2022 18:52:49 +0100 From: Ionela Voinescu To: Sudeep Holla Cc: linux-kernel@vger.kernel.org, conor.dooley@microchip.com, Greg Kroah-Hartman , Vincent Guittot , Dietmar Eggemann , Pierre Gondois , linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH -next] arch_topology: Fix cache attributes detection in the CPU hotplug path Message-ID: References: <20220713133344.1201247-1-sudeep.holla@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20220713133344.1201247-1-sudeep.holla@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220714_105257_319094_540BB4D5 X-CRM114-Status: GOOD ( 27.47 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org Hi Sudeep, Thank you for the fix! On Wednesday 13 Jul 2022 at 14:33:44 (+0100), Sudeep Holla wrote: > init_cpu_topology() is called only once at the boot and all the cache > attributes are detected early for all the possible CPUs. However when > the CPUs are hotplugged out, the cacheinfo gets removed. While the > attributes are added back when the CPUs are hotplugged back in as part > of CPU hotplug state machine, it ends up called quite late after the > update_siblings_masks() are called in the secondary_start_kernel() > resulting in wrong llc_sibling_masks. > > Move the call to detect_cache_attributes() inside update_siblings_masks() > to ensure the cacheinfo is updated before the LLC sibling masks are > updated. This will fix the incorrect LLC sibling masks generated when > the CPUs are hotplugged out and hotplugged back in again. > > Reported-by: Ionela Voinescu > Signed-off-by: Sudeep Holla > --- > drivers/base/arch_topology.c | 16 ++++++---------- > 1 file changed, 6 insertions(+), 10 deletions(-) > > Hi Conor, > > Ionela reported an issue with the CPU hotplug and as a fix I need to > move the call to detect_cache_attributes() which I had thought to keep > it there from first but for no reason had moved it to init_cpu_topology(). > > Wonder if this fixes the -ENOMEM on RISC-V as this one is called on the > cpu in the secondary CPUs init path while init_cpu_topology executed > detect_cache_attributes() for all possible CPUs much earlier. I think > this might help as the percpu memory might be initialised in this case. > > Anyways give this a try, also test the CPU hotplug and check if nothing > is broken on RISC-V. We noticed this bug only on one platform while > > Regards, > Sudeep > > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c > index 441e14ac33a4..0424b59b695e 100644 > --- a/drivers/base/arch_topology.c > +++ b/drivers/base/arch_topology.c > @@ -732,7 +732,11 @@ const struct cpumask *cpu_clustergroup_mask(int cpu) > void update_siblings_masks(unsigned int cpuid) > { > struct cpu_topology *cpu_topo, *cpuid_topo = &cpu_topology[cpuid]; > - int cpu; > + int cpu, ret; > + > + ret = detect_cache_attributes(cpuid); > + if (ret) > + pr_info("Early cacheinfo failed, ret = %d\n", ret); > /* update core and thread sibling masks */ > for_each_online_cpu(cpu) { > @@ -821,7 +825,7 @@ __weak int __init parse_acpi_topology(void) > #if defined(CONFIG_ARM64) || defined(CONFIG_RISCV) > void __init init_cpu_topology(void) > { > - int ret, cpu; > + int ret; > reset_cpu_topology(); > ret = parse_acpi_topology(); > @@ -836,13 +840,5 @@ void __init init_cpu_topology(void) > reset_cpu_topology(); > return; > } > - > - for_each_possible_cpu(cpu) { > - ret = detect_cache_attributes(cpu); > - if (ret) { > - pr_info("Early cacheinfo failed, ret = %d\n", ret); > - break; > - } > - } > } > #endif > --2.37.1 > Reviewed-by: Ionela Voinescu Tested-by: Ionela Voinescu Kind regards, Ionela. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv