Received: by 2002:a05:6a10:206:0:0:0:0 with SMTP id 6csp58217pxj; Wed, 26 May 2021 16:05:16 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxAoyApIkPAUYoL707b85iQD+JHTkKjFyUmy5lJqKAN5wYZ197xfBIvrhleckQLos+JqE7s X-Received: by 2002:a17:906:a1d9:: with SMTP id bx25mr614787ejb.363.1622070315983; Wed, 26 May 2021 16:05:15 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1622070315; cv=none; d=google.com; s=arc-20160816; b=j+98MpfBOMEpGB2KggxD7NRjHTnmDI21Zi6JFHM+NRYa6bNXiJ1ILM25hjf1yetqS6 VHYL4fZ1yK9hyt7fukQJIg5PoclVq1+bU7SdU9xrlC5mu9u9qKcaXl6GXaIHCyvZfYJw 1+jqXONLSlT4zvyzEI4RKpFe7Qx7R4rSK+s8qmsyyro0kEPoHOBwpZ0akpnQGHgJHGfF bMvh05pBHglAyBZfpzrgNUd8uF+g+ynaZ8ndvpsWyZgFPmJEYr51ObBs9oV0dFRxeXN2 qUyHnlo1v3n8yPn5zVpMhfUKZ+P70s2rPIu9qNyMnulyvjPaWqHvjvO3XTLmXhGVr4le C+zA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:content-language :in-reply-to:mime-version:user-agent:date:message-id:from:references :cc:to:subject; bh=kCKuUGor7rAtQB9bBKTVnERjK8nSBiuetpwMDegCLcY=; b=j0C/cHaMeX6gLPQYlQp+Zs+hYYwUe23KqtsjJBksuB/nnxXGxbkHcKPSQRzIkayXYG +0X9G3+dN/B9rycECJhPsCR8cuOOFgpEePcldbUp6Sxrgwce5umikYLV65DZvbdrtfe6 HtKfGrmvR00MzMktPJ+riG6cTx1VMN+59E6vxmDMDbiYDyl/qh8SM0Htd32e85+Vbi8d RhM5/kKXR0QMROdBYTyAWGrWxpMjc2dEjFx4W8hOc978z1goXRm8eUxsP+bejP77NMkH iyNXTVC0GKf0TCTuxXT8yMLrDmEXjDnKiy6j4LQms/QDzw1epZyy2j+u3xSwVywBr5JO 5hJw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id i3si375973ejd.48.2021.05.26.16.04.27; Wed, 26 May 2021 16:05:15 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=arm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234978AbhEZSTQ (ORCPT + 99 others); Wed, 26 May 2021 14:19:16 -0400 Received: from foss.arm.com ([217.140.110.172]:48332 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229870AbhEZSTP (ORCPT ); Wed, 26 May 2021 14:19:15 -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 303AB13A1; Wed, 26 May 2021 11:17:43 -0700 (PDT) Received: from [192.168.178.6] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8EE0F3F73B; Wed, 26 May 2021 11:17:41 -0700 (PDT) Subject: Re: [PATCH v5 2/3] sched/topology: Rework CPU capacity asymmetry detection To: Beata Michalska Cc: Valentin Schneider , linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, corbet@lwn.net, rdunlap@infradead.org, linux-doc@vger.kernel.org References: <20210524101617.8965-1-beata.michalska@arm.com> <20210524101617.8965-3-beata.michalska@arm.com> <87fsyc6mfz.mognet@arm.com> <20210524225508.GA14880@e120325.cambridge.arm.com> <87a6oj6sxo.mognet@arm.com> <20210525102945.GA24210@e120325.cambridge.arm.com> <98ad8837-b9b8-ff50-5a91-8d5951ee757c@arm.com> <20210526121546.GA13262@e120325.cambridge.arm.com> From: Dietmar Eggemann Message-ID: <1cae4fcc-d276-f66d-c094-35571233d923@arm.com> Date: Wed, 26 May 2021 20:17:25 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210526121546.GA13262@e120325.cambridge.arm.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 26/05/2021 14:15, Beata Michalska wrote: > On Wed, May 26, 2021 at 11:52:25AM +0200, Dietmar Eggemann wrote: >> On 25/05/2021 12:29, Beata Michalska wrote: >>> On Tue, May 25, 2021 at 10:53:07AM +0100, Valentin Schneider wrote: >>>> On 24/05/21 23:55, Beata Michalska wrote: >>>>> On Mon, May 24, 2021 at 07:01:04PM +0100, Valentin Schneider wrote: >>>>>> On 24/05/21 11:16, Beata Michalska wrote: [...] >> static inline int >> asym_cpu_capacity_classify(struct sched_domain *sd, >> const struct cpumask *cpu_map) >> { >> int sd_span_match = 0, cpu_map_match = 0, flags = 0; >> struct asym_cap_data *entry; >> >> list_for_each_entry(entry, &asym_cap_list, link) { >> if (cpumask_intersects(sched_domain_span(sd), entry->cpu_mask)) >> ++sd_span_match; >> else if (cpumask_intersects(cpu_map, entry->cpu_mask)) >> ++cpu_map_match; >> } >> >> WARN_ON_ONCE(!sd_span_match); >> >> if (sd_span_match > 1) { >> flags |= SD_ASYM_CPUCAPACITY; >> if (!cpu_map_match) >> flags |= SD_ASYM_CPUCAPACITY_FULL; >> } >> >> return flags; >> } > So I planned to drop the list_is_singular check as it is needless really. > Otherwise, I am not really convinced by the suggestion. I could add comments > around current version to make it more ..... 'digestible' but I'd rather > stay with it as it seems more compact to me (subjective). You could pass in `const struct cpumask *sd_span` instead of `struct sched_domain *sd` though. To make it clear that both masks are used to compare against the cpumasks of the asym_cap_list entries. static inline int -asym_cpu_capacity_classify(struct sched_domain *sd, +asym_cpu_capacity_classify(const struct cpumask *sd_span, const struct cpumask *cpu_map) { int sd_asym_flags = SD_ASYM_CPUCAPACITY | SD_ASYM_CPUCAPACITY_FULL; @@ -1377,14 +1378,14 @@ asym_cpu_capacity_classify(struct sched_domain *sd, goto leave; list_for_each_entry(entry, &asym_cap_list, link) { - if (cpumask_intersects(sched_domain_span(sd), entry->cpu_mask)) { + if (cpumask_intersects(sd_span, entry->cpu_mask)) { ++asym_cap_count; } else { /* * CPUs with given capacity might be offline * so make sure this is not the case */ - if (cpumask_intersects(entry->cpu_mask, cpu_map)) { + if (cpumask_intersects(cpu_map, entry->cpu_mask)) { sd_asym_flags &= ~SD_ASYM_CPUCAPACITY_FULL; if (asym_cap_count > 1) break; @@ -1395,7 +1396,6 @@ asym_cpu_capacity_classify(struct sched_domain *sd, leave: return asym_cap_count > 1 ? sd_asym_flags : 0; } -#endif static inline struct asym_cap_data * asym_cpu_capacity_get_data(unsigned long capacity) @@ -1589,6 +1589,7 @@ sd_init(struct sched_domain_topology_level *tl, struct sd_data *sdd = &tl->data; struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); int sd_id, sd_weight, sd_flags = 0; + struct cpumask *sd_span; #ifdef CONFIG_NUMA /* @@ -1636,10 +1637,11 @@ sd_init(struct sched_domain_topology_level *tl, #endif }; - cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); - sd_id = cpumask_first(sched_domain_span(sd)); + sd_span = sched_domain_span(sd); + cpumask_and(sd_span, cpu_map, tl->mask(cpu)); + sd_id = cpumask_first(sd_span); - sd->flags |= asym_cpu_capacity_classify(sd, cpu_map); + sd->flags |= asym_cpu_capacity_classify(sd_span, cpu_map); /* * Convert topological properties into behaviour. */