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 30219C7EE23 for ; Thu, 8 Jun 2023 06:34:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234760AbjFHGeH (ORCPT ); Thu, 8 Jun 2023 02:34:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234720AbjFHGeA (ORCPT ); Thu, 8 Jun 2023 02:34:00 -0400 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48B252113 for ; Wed, 7 Jun 2023 23:33:33 -0700 (PDT) Received: by mail-pg1-x530.google.com with SMTP id 41be03b00d2f7-53fbb3a013dso103599a12.1 for ; Wed, 07 Jun 2023 23:33:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1686206013; x=1688798013; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=miu0m+9Tm1uoegobE94Ng9PUSsisbRCvMO54PFQ9FXA=; b=J2eRYyxcjSLdIsZK45qLtsrvuNkwMWsQXmFlkud7KqjiXcUk1nY6DC8PGCcqy0nmMb DtwfQFWLrYgbw6KDqOCbMhibo2TKQWXsi8sO2pDPkteo9ffY8OKOVQBhjzw3WvvO+ufs iyl/iHuGyWeCSLwWlhNWDhs495TAZ6cOz1KHj5w35uN0+zqjYmt+UMvxWqoy8gwkJWC8 32HO5tLc9pjzbCTw24WrrAcMIR66NppqcoV/kWv+bPIsnVXfY2y/sCNyGHEveU5PXhMX ZzsFaUATXBOOxMEQSCdH0Cp3wtr54k6jl1Ld78N3k3/50OJER2d/qbeJ/nEETKjO/aEz y9xw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686206013; x=1688798013; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=miu0m+9Tm1uoegobE94Ng9PUSsisbRCvMO54PFQ9FXA=; b=JjBkK6P2pBf5JoCUwo3yBq5FR2fSf2o8nDbs2Oq9BYiPIYKvbeaHuaXP9K1BMP7/MA GhYzFJj7Pibe1f1LoU8ip8AbCVK9WP+ORpRXeXlv4PNZp/1oYk71yyR3AkSfOIahOy/Q KAIOMVlbsY1EKm1gLFmJbq7Cg7w16Py31rLO+N6ySLmEDVtwD10eyOCftDX4kvROqKjO /erbf6iL52KoiI3iRkEw5LoJC8e8gya0JSJ4aUW2x4BAnhFkP892FNcJhLHvQpfVGCxQ 2ABUgz78Tx/6NWT4XEEaetM+Sl59hOyntdyM7b5YlwYSRyrbgUp03CNw1gwuI05AcUIS EQ+Q== X-Gm-Message-State: AC+VfDyKDRWd4650J6cFRA+OZQbepkdlwwFabDAVAa5PlnzHcBE8TTqt cdBfL5Qe8grMrLa4U+R2PdMplA== X-Google-Smtp-Source: ACHHUZ7ItfOjl5dsrzp0GWRZLSS/iHwXakftJkx9kELNaxuK/TfqNPljoBUdN6vwzwB01SkyOVsZQQ== X-Received: by 2002:a17:90b:685:b0:256:87f4:432a with SMTP id m5-20020a17090b068500b0025687f4432amr6736938pjz.18.1686206012769; Wed, 07 Jun 2023 23:33:32 -0700 (PDT) Received: from C02G87K0MD6R.bytedance.net ([203.208.167.147]) by smtp.gmail.com with ESMTPSA id c15-20020a17090abf0f00b0025645d118adsm542039pjs.14.2023.06.07.23.33.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Jun 2023 23:33:32 -0700 (PDT) From: Hao Jia To: mingo@redhat.com, peterz@infradead.org, mingo@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, mgorman@techsingularity.net Cc: linux-kernel@vger.kernel.org, Hao Jia Subject: [PATCH v4 1/4] sched/core: Fixed missing rq clock update before calling set_rq_offline() Date: Thu, 8 Jun 2023 14:33:09 +0800 Message-Id: <20230608063312.79440-2-jiahao.os@bytedance.com> X-Mailer: git-send-email 2.37.0 (Apple Git-136) In-Reply-To: <20230608063312.79440-1-jiahao.os@bytedance.com> References: <20230608063312.79440-1-jiahao.os@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is triggered during cpu offline when CONFIG_CPU_FREQ is enabled and cpufreq is set to powersave: ------------[ cut here ]------------ rq->clock_update_flags < RQCF_ACT_SKIP WARNING: CPU: 24 PID: 754 at kernel/sched/sched.h:1496 enqueue_top_rt_rq+0x139/0x160 Call Trace: ? intel_pstate_update_util+0x3b0/0x3b0 rq_offline_rt+0x1b7/0x250 set_rq_offline.part.120+0x28/0x60 rq_attach_root+0xc4/0xd0 cpu_attach_domain+0x3dc/0x7f0 ? __schedule+0x65e/0x1310 partition_sched_domains_locked+0x2a5/0x3c0 rebuild_sched_domains_locked+0x477/0x830 ? percpu_rwsem_wait+0x140/0x140 rebuild_sched_domains+0x1b/0x30 cpuset_hotplug_workfn+0x2ca/0xc90 ? balance_push+0x56/0x120 ? _raw_spin_unlock+0x15/0x30 ? finish_task_switch+0x98/0x2f0 ? __switch_to+0x116/0x410 ? __schedule+0x65e/0x1310 ? internal_add_timer+0x42/0x60 ? _raw_spin_unlock_irqrestore+0x23/0x40 ? add_timer_on+0xd5/0x130 process_one_work+0x1bc/0x3d0 worker_thread+0x4c/0x380 ? preempt_count_add+0x56/0xa0 ? rescuer_thread+0x310/0x310 kthread+0xe6/0x110 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 More detailed key function call graph: rq_offline_rt() __disable_runtime() sched_rt_rq_enqueue() enqueue_top_rt_rq() cpufreq_update_util() <-- depends on CONFIG_CPU_FREQ data->func(data, *rq_clock(rq)*, flags) intel_pstate_update_util() <-- powersave policy callback function Before calling set_rq_offline() we need to update the rq clock to avoid using the old rq clock, and use rq_lock_irqsave()/rq_unlock_irqrestore() to replace raw_spin_rq_lock_irqsave()/raw_spin_rq_unlock_irqrestore() to ensure that rq->clock_update_flags are cleared before updating the rq clock. Steps to reproduce: 1. Enable CONFIG_SMP and CONFIG_CPU_FREQ when compiling the kernel 2. echo 1 > /sys/kernel/debug/clear_warn_once 3. cpupower -c all frequency-set -g powersave 4. Run some rt tasks e.g. Create 5*n rt (100% running) tasks (on a system with n CPUs) 5. Offline cpu one by one until the warninng is triggered Signed-off-by: Hao Jia Reviewed-by: Vincent Guittot --- kernel/sched/topology.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index 6682535e37c8..b89497696880 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -487,15 +487,17 @@ static void free_rootdomain(struct rcu_head *rcu) void rq_attach_root(struct rq *rq, struct root_domain *rd) { struct root_domain *old_rd = NULL; - unsigned long flags; + struct rq_flags rf; - raw_spin_rq_lock_irqsave(rq, flags); + rq_lock_irqsave(rq, &rf); if (rq->rd) { old_rd = rq->rd; - if (cpumask_test_cpu(rq->cpu, old_rd->online)) + if (cpumask_test_cpu(rq->cpu, old_rd->online)) { + update_rq_clock(rq); set_rq_offline(rq); + } cpumask_clear_cpu(rq->cpu, old_rd->span); @@ -515,7 +517,7 @@ void rq_attach_root(struct rq *rq, struct root_domain *rd) if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) set_rq_online(rq); - raw_spin_rq_unlock_irqrestore(rq, flags); + rq_unlock_irqrestore(rq, &rf); if (old_rd) call_rcu(&old_rd->rcu, free_rootdomain); -- 2.37.0 (Apple Git-136)