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 7AC1EC0032E for ; Wed, 25 Oct 2023 17:56:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234451AbjJYR4k (ORCPT ); Wed, 25 Oct 2023 13:56:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46910 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234479AbjJYR4f (ORCPT ); Wed, 25 Oct 2023 13:56:35 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 021DF181 for ; Wed, 25 Oct 2023 10:56:33 -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 5F8E71474; Wed, 25 Oct 2023 10:57:14 -0700 (PDT) Received: from [10.1.197.60] (eglon.cambridge.arm.com [10.1.197.60]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 400DD3F738; Wed, 25 Oct 2023 10:56:30 -0700 (PDT) Message-ID: Date: Wed, 25 Oct 2023 18:56:28 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v6 10/24] x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty_rmid Content-Language: en-GB To: babu.moger@amd.com, x86@kernel.org, linux-kernel@vger.kernel.org Cc: Fenghua Yu , Reinette Chatre , Thomas Gleixner , Ingo Molnar , Borislav Petkov , H Peter Anvin , shameerali.kolothum.thodi@huawei.com, D Scott Phillips OS , carl@os.amperecomputing.com, lcherian@marvell.com, bobo.shaobowang@huawei.com, tan.shaopeng@fujitsu.com, xingxin.hx@openanolis.org, baolin.wang@linux.alibaba.com, Jamie Iles , Xin Hao , peternewman@google.com, dfustini@baylibre.com, amitsinght@marvell.com References: <20230914172138.11977-1-james.morse@arm.com> <20230914172138.11977-11-james.morse@arm.com> <1dc0fb2f-7b68-d1b3-e6fe-bf341afb545d@amd.com> From: James Morse In-Reply-To: <1dc0fb2f-7b68-d1b3-e6fe-bf341afb545d@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Babu, On 05/10/2023 21:26, Moger, Babu wrote: > On 9/14/2023 12:21 PM, James Morse wrote: >> MPAM's PMG bits extend its PARTID space, meaning the same PMG value can be >> used for different control groups. >> >> This means once a CLOSID is allocated, all its monitoring ids may still be >> dirty, and held in limbo. >> >> Instead of allocating the first free CLOSID, on architectures where >> CONFIG_RESCTRL_RMID_DEPENDS_ON_COSID is enabled, search >> closid_num_dirty_rmid[] to find the cleanest CLOSID. >> >> The CLOSID found is returned to closid_alloc() for the free list >> to be updated. >> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c >> b/arch/x86/kernel/cpu/resctrl/rdtgroup.c >> index fa449ee0d1a7..1f8f1c417a4b 100644 >> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c >> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c >> @@ -132,11 +132,20 @@ static void closid_init(void) >>     static int closid_alloc(void) >>   { >> -    u32 closid = ffs(closid_free_map); >> +    u32 closid; >> +    int err; > Naming "err" seems odd here.  How about cleanest_closid ? That's just habit because the value might be an error code until its been checked, and once it has, its called 'closid'. But sure, if you think that is clearer. Thanks, James