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 99155C6FD20 for ; Fri, 24 Mar 2023 11:35:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231135AbjCXLfP (ORCPT ); Fri, 24 Mar 2023 07:35:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38474 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229508AbjCXLfN (ORCPT ); Fri, 24 Mar 2023 07:35:13 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 971001CACA for ; Fri, 24 Mar 2023 04:35:12 -0700 (PDT) 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 6DC2611FB; Fri, 24 Mar 2023 04:35:56 -0700 (PDT) Received: from bogus (e103737-lin.cambridge.arm.com [10.1.197.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 29D493F6C4; Fri, 24 Mar 2023 04:35:11 -0700 (PDT) Date: Fri, 24 Mar 2023 11:35:08 +0000 From: Sudeep Holla To: Pierre Gondois Cc: Yicong Yang , gregkh@linuxfoundation.org, rafael@kernel.org, palmer@rivosinc.com, linux-kernel@vger.kernel.org, prime.zeng@hisilicon.com, linuxarm@huawei.com, yangyicong@hisilicon.com Subject: Re: [PATCH] cacheinfo: Fix LLC is not exported through sysfs Message-ID: <20230324113508.x2rt52aakruwelk3@bogus> References: <20230323122528.16691-1-yangyicong@huawei.com> <7cca5e74-6626-1c8b-9309-47b9f5d4395f@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7cca5e74-6626-1c8b-9309-47b9f5d4395f@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 23, 2023 at 06:58:53PM +0100, Pierre Gondois wrote: > Hello Yicong, > > FWIW, I think the patch is correct and I could reproduce the issue. > > On 3/23/23 13:25, Yicong Yang wrote: > > From: Yicong Yang > > > > After entering 6.3-rc1 the LLC cacheinfo is not exported on our ACPI > > based arm64 server. This is because the LLC cacheinfo is partly reset > > when secondary CPUs boot up. On arm64 the primary cpu will allocate > > and setup cacheinfo: > > init_cpu_topology() > > for_each_possible_cpu() > > fetch_cache_info() // Allocate cacheinfo and init levels > > detect_cache_attributes() > > cache_shared_cpu_map_setup() > > if (!last_level_cache_is_valid()) // not valid, setup LLC > > cache_setup_properties() // setup LLC > > > > On secondary CPU boot up: > > detect_cache_attributes() > > populate_cache_leaves() > > get_cache_type() // Get cache type from clidr_el1, > > // for LLC type=CACHE_TYPE_NOCACHE > > cache_shared_cpu_map_setup() > > if (!last_level_cache_is_valid()) // Valid and won't go to this branch, > > // leave LLC's type=CACHE_TYPE_NOCACHE > > > > The last_level_cache_is_valid() use cacheinfo->{attributes, fw_token} to > > test it's valid or not, but populate_cache_leaves() will only reset > > LLC's type, so we won't try to re-setup LLC's type and leave it > > CACHE_TYPE_NOCACHE and won't export it through sysfs. > > IIUC this is for the case where arch register doesn't report the system level cache. I wonder if it makes sense to fix the arch callback to deal with that instead of here. I am fine either way, just checking as ideally it is something populate_cache_leaves() is messing up. [...] > > @@ -481,6 +488,7 @@ int detect_cache_attributes(unsigned int cpu) > > if (ret) > > goto free_ci; > > +update_cpu_map: > > Maybe just a suggestion about the code itself, > it should be possible to replace the 'goto' by an 'if' condition. > (Similarly, the 'populate_leaves:' label could have been avoided.) > Agreed, I prefer that as well. -- Regards, Sudeep