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 E66C0C43334 for ; Wed, 13 Jul 2022 14:04:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235935AbiGMOEE (ORCPT ); Wed, 13 Jul 2022 10:04:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234001AbiGMOEC (ORCPT ); Wed, 13 Jul 2022 10:04:02 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 993572FFF9 for ; Wed, 13 Jul 2022 07:04:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 4EBADB81FC6 for ; Wed, 13 Jul 2022 14:04:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A5C2C34114; Wed, 13 Jul 2022 14:03:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657721039; bh=9IGH4MQdi/KGvLaBbSpVE1u3UFTp0yNqx8UIwCBrNzk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=N41phYccyuE63ABZmUcfr3okC4jpwzGUm6l59osfsReDlNcsLoQqadbj6yYHvKIEc CTHf8yXBLNGIsUZbTiOGA9CPSrUtf2EQ/O4BKi9wy8tw++1A3LCCK/1RScJ0nvGRB4 0iiS5yJURy2dzfKYlYx/pNYrE0vxjZ09F+qdWmTM= Date: Wed, 13 Jul 2022 16:03:56 +0200 From: Greg Kroah-Hartman To: Sudeep Holla Cc: linux-kernel@vger.kernel.org, conor.dooley@microchip.com, Vincent Guittot , Dietmar Eggemann , Ionela Voinescu , 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-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220713133344.1201247-1-sudeep.holla@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 13, 2022 at 02:33:44PM +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); No erroring out? thanks, greg k-h