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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 C7500C10DCE for ; Wed, 18 Mar 2020 12:22:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9D55420772 for ; Wed, 18 Mar 2020 12:22:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726774AbgCRMWY (ORCPT ); Wed, 18 Mar 2020 08:22:24 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:2573 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726619AbgCRMWY (ORCPT ); Wed, 18 Mar 2020 08:22:24 -0400 Received: from LHREML712-CAH.china.huawei.com (unknown [172.18.7.108]) by Forcepoint Email with ESMTP id C98881FDEC3ADA6D060B; Wed, 18 Mar 2020 12:22:22 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by LHREML712-CAH.china.huawei.com (10.201.108.35) with Microsoft SMTP Server (TLS) id 14.3.408.0; Wed, 18 Mar 2020 12:22:22 +0000 Received: from [127.0.0.1] (10.47.11.44) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Wed, 18 Mar 2020 12:22:21 +0000 Subject: Re: [PATCH v3 2/2] irqchip/gic-v3-its: Balance initial LPI affinity across CPUs To: Marc Zyngier , , CC: chenxiang , Zhou Wang , Ming Lei , Jason Cooper , Thomas Gleixner , "luojiaxing@huawei.com" References: <20200316115433.9017-1-maz@kernel.org> <20200316115433.9017-3-maz@kernel.org> From: John Garry Message-ID: Date: Wed, 18 Mar 2020 12:22:09 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <20200316115433.9017-3-maz@kernel.org> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.11.44] X-ClientProxiedBy: lhreml721-chm.china.huawei.com (10.201.108.72) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I may have an idea about this: irq 196, cpu list 0-31, effective list 82 Just going back to comment on the code: > +/* > + * As suggested by Thomas Gleixner in: > + * https://lore.kernel.org/r/87h80q2aoc.fsf@nanos.tec.linutronix.de > + */ > +static int its_select_cpu(struct irq_data *d, > + const struct cpumask *aff_mask) > +{ > + struct its_device *its_dev = irq_data_get_irq_chip_data(d); > + cpumask_var_t tmpmask; > + int cpu, node; > + > + if (!alloc_cpumask_var(&tmpmask, GFP_KERNEL)) > + return -ENOMEM; > + > + node = its_dev->its->numa_node; > + > + if (!irqd_affinity_is_managed(d)) { > + /* First try the NUMA node */ > + if (node != NUMA_NO_NODE) { > + /* > + * Try the intersection of the affinity mask and the > + * node mask (and the online mask, just to be safe). > + */ > + cpumask_and(tmpmask, cpumask_of_node(node), aff_mask); > + cpumask_and(tmpmask, tmpmask, cpu_online_mask); > + > + /* If that doesn't work, try the nodemask itself */ So if tmpmsk is empty... > + if (cpumask_empty(tmpmask)) > + cpumask_and(tmpmask, cpumask_of_node(node), cpu_online_mask); now the tmpmask may have no intersection with the aff_mask... > + > + cpu = cpumask_pick_least_loaded(d, tmpmask); > + if (cpu < nr_cpu_ids) > + goto out; > + > + /* If we can't cross sockets, give up */ > + if ((its_dev->its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144)) > + goto out; > + > + /* If the above failed, expand the search */ > + } SNIP > +out: > + free_cpumask_var(tmpmask); > + > + pr_debug("IRQ%d -> %*pbl CPU%d\n", d->irq, cpumask_pr_args(aff_mask), cpu); > + return cpu; > +} > + > static int its_set_affinity(struct irq_data *d, const struct cpumask *mask_val, > bool force) > { > - unsigned int cpu; > - const struct cpumask *cpu_mask = cpu_online_mask; > struct its_device *its_dev = irq_data_get_irq_chip_data(d); > struct its_collection *target_col; > u32 id = its_get_event_id(d); > + int cpu; > > /* A forwarded interrupt should use irq_set_vcpu_affinity */ > if (irqd_is_forwarded_to_vcpu(d)) > return -EINVAL; > > - /* lpi cannot be routed to a redistributor that is on a foreign node */ > - if (its_dev->its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144) { > - if (its_dev->its->numa_node >= 0) { > - cpu_mask = cpumask_of_node(its_dev->its->numa_node); > - if (!cpumask_intersects(mask_val, cpu_mask)) > - return -EINVAL; > - } > - } > - > - cpu = cpumask_any_and(mask_val, cpu_mask); > + if (!force) > + cpu = its_select_cpu(d, mask_val); > + else > + cpu = cpumask_pick_least_loaded(d, mask_val); > > - if (cpu >= nr_cpu_ids) > + if (cpu < 0 || cpu >= nr_cpu_ids) > return -EINVAL; Annotate missing code: if (cpu < 0 || cpu >= nr_cpu_ids) return -EINVAL; if (cpu != its_dev->event_map.col_map[id]) { its_inc_lpi_count(d, cpu); its_dec_lpi_count(d, its_dev->event_map.col_map[id]); target_col = &its_dev->its->collections[cpu]; its_send_movi(its_dev, target_col, id); its_dev->event_map.col_map[id] = cpu; irq_data_update_effective_affinity(d, cpumask_of(cpu)); } So cpu may not be a member of mask_val. Hence the inconsistency of the affinity list and effective affinity. We could just drop the AND of the ITS node mask in its_select_cpu(). Anyway, I don't think that this should stop us testing. Cheers, John