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 X-Spam-Level: X-Spam-Status: No, score=-13.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6A871C55179 for ; Tue, 27 Oct 2020 09:58:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EFE82225C for ; Tue, 27 Oct 2020 09:58:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2896594AbgJ0J6b (ORCPT ); Tue, 27 Oct 2020 05:58:31 -0400 Received: from foss.arm.com ([217.140.110.172]:37030 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2410433AbgJ0J6A (ORCPT ); Tue, 27 Oct 2020 05:58:00 -0400 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 A5AFD30E; Tue, 27 Oct 2020 02:57:59 -0700 (PDT) Received: from [192.168.178.2] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C35C13F66E; Tue, 27 Oct 2020 02:57:57 -0700 (PDT) Subject: Re: [PATCH v2] sched: sched_domain fix highest_flag_domain function To: Xuewen Yan , xuewen.yan@unisoc.com, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org Cc: rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, linux-kernel@vger.kernel.org References: <1603769572-8193-1-git-send-email-xuewen.yan94@gmail.com> From: Dietmar Eggemann Message-ID: <69257e98-2d93-673a-5dac-e11b6d5610be@arm.com> Date: Tue, 27 Oct 2020 10:57:56 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <1603769572-8193-1-git-send-email-xuewen.yan94@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 27/10/2020 04:32, Xuewen Yan wrote: > the highest_flag_domain is to search the highest sched_domain > containing flag, but if the lower sched_domain didn't contain > the flag, but the higher sched_domain contains the flag, the > function will return NULL instead of the higher sched_domain. > > For example: > In MC domain : no SD_ASYM_CPUCAPACITY flag; > In DIE domain : containing SD_ASYM_CPUCAPACITY flag; > the "highest_flag_domain(cpu, SD_ASYM_CPUCAPACITY)" will return NULL. > > Signed-off-by: Xuewen Yan > --- > kernel/sched/sched.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h > index 28709f6..2c7c566 100644 > --- a/kernel/sched/sched.h > +++ b/kernel/sched/sched.h > @@ -1427,7 +1427,7 @@ static inline struct sched_domain *highest_flag_domain(int cpu, int flag) > > for_each_domain(cpu, sd) { > if (!(sd->flags & flag)) > - break; > + continue; > hsd = sd; > } We distinguish between SDF_SHARED_PARENT and SDF_SHARED_CHILD SD flags. 1 SD_FLAG(*SD_ASYM_CPUCAPACITY*, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) 2 SD_FLAG(SD_SERIALIZE, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) 3 SD_FLAG(SD_OVERLAP, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) 4 SD_FLAG(SD_NUMA, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) 1 SD_FLAG(SD_BALANCE_NEWIDLE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 2 SD_FLAG(SD_BALANCE_EXEC, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 3 SD_FLAG(SD_BALANCE_FORK, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 4 SD_FLAG(SD_BALANCE_WAKE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 5 82 SD_FLAG(SD_WAKE_AFFINE, SDF_SHARED_CHILD) 6 SD_FLAG(SD_SHARE_CPUCAPACITY, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 7 SD_FLAG(SD_SHARE_PKG_RESOURCES, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) 8 SD_FLAG(SD_ASYM_PACKING, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) We call lowest_flag_domain() on SDF_SHARED_PARENT and highest_flag_domain() on SDF_SHARED_CHILD SD flags. 1 sd = lowest_flag_domain(cpu, SD_NUMA); 2 sd = lowest_flag_domain(cpu, *SD_ASYM_CPUCAPACITY*); 1 sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); 2 sd = highest_flag_domain(cpu, SD_ASYM_PACKING);