From patchwork Wed Jul 13 13:33:44 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sudeep Holla X-Patchwork-Id: 12916727 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 1B23AC43334 for ; Wed, 13 Jul 2022 13:34:59 +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: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:In-Reply-To:References: List-Owner; bh=o/X4Bd5XuaHgrs2rysMGfYQ1NZ8ql28XvflYD95sW6s=; b=qBQfQpo1MUrS9b kclPY5S02FY42hKK+MnxQcILodp1lqllHUB6/aEomXUkuJdfAjNrMMf7gqL+fzl3pVHiMtJQFYSV/ 6csdwBey9AAyN5WXAIdHRwmAoOf3fht95xxTyJlutrNJwCaRazw1JwsP1bpSBd3gWn4OoXHFQAIK4 F2TijcL8cU6FEUl8LhqtewHRDLq0D2FcvhqpUNKyzWNj185j5JVwAkFLkblzaF8SYXiJ/NZUKQnu3 PNnxnVN0omdCxqRuwMasad8fMNonAbrzBGuRmWshtfkiGuM3FEYSNPNDxdVmTBrc0xmVxohgyp2Tg mM7E5hpquQ19w9ELGr2g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oBcV7-003yAf-2g; Wed, 13 Jul 2022 13:34:01 +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 1oBcV3-003y7M-6T; Wed, 13 Jul 2022 13:33:59 +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 737341424; Wed, 13 Jul 2022 06:33:52 -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 AF71B3F73D; Wed, 13 Jul 2022 06:33:50 -0700 (PDT) From: Sudeep Holla To: linux-kernel@vger.kernel.org, conor.dooley@microchip.com Cc: Sudeep Holla , Greg Kroah-Hartman , Vincent Guittot , Dietmar Eggemann , Ionela Voinescu , Pierre Gondois , linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org Subject: [PATCH -next] arch_topology: Fix cache attributes detection in the CPU hotplug path Date: Wed, 13 Jul 2022 14:33:44 +0100 Message-Id: <20220713133344.1201247-1-sudeep.holla@arm.com> X-Mailer: git-send-email 2.37.1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220713_063357_320642_C004E13D X-CRM114-Status: GOOD ( 15.71 ) X-BeenThere: linux-arm-kernel@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-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 Reviewed-by: Conor Dooley Reviewed-by: Ionela Voinescu Tested-by: Ionela Voinescu --- 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 #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 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)