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[2620:137:e000::1:20]) by mx.google.com with ESMTP id d14-20020a63f24e000000b004fbf520c66csi10336662pgk.254.2023.04.10.01.21.42; Mon, 10 Apr 2023 01:21:54 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@bytedance.com header.s=google header.b=Khr9IhgN; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=bytedance.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229720AbjDJIMw (ORCPT + 99 others); Mon, 10 Apr 2023 04:12:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229562AbjDJIMu (ORCPT ); Mon, 10 Apr 2023 04:12:50 -0400 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60AD64C09 for ; Mon, 10 Apr 2023 01:12:25 -0700 (PDT) Received: by mail-pj1-x102f.google.com with SMTP id l9-20020a17090a3f0900b0023d32684e7fso12236788pjc.1 for ; Mon, 10 Apr 2023 01:12:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1681114345; 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=6WO1hmjM9xrdhdfZ2YJyh200yOP7FbYCQwTl3LGlR2E=; b=Khr9IhgNJ5cV2AUUZJCzgmpfjQeCq5F4q0I4qkC2Xwzyy5GYhz1pImevaeLLaryBwP kIT2SosLbtF0XrppmFuFzkUlOVkzS/YNwUJ+A0FpHJVJKPoOulitINFM4HJ6VedovZpq 7OxWrL2J+dE1JCY+GhOVFTqWjqh0hkdU+zI31IegsIHcjeazQWSGm9j8rJL2Pf9bOnw6 oeUVNJNN2jiYdnQQfOvoqUvpdv+35J5crPSHXkrOyzllHZMIztAo7Vod1/NOPSblsnNR 9XxhdXpfKDSgVieKQlQH8+Vw2jlKyNZNnxerJa28Nt7K1DrU3cVV2XKcRKIppD2IyDDV EHxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1681114345; 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=6WO1hmjM9xrdhdfZ2YJyh200yOP7FbYCQwTl3LGlR2E=; b=wVQDKyzq3z9UdFB+TTcFAfFEnVG9kHdBQeBxv+JD9WhvljARt/OhM+X9hcAs8FFIQA KEc65k0A760jDp3mc7MgRcPQpvl0ynCiI0YcPIjZSChgm06wCIwob2N/fgpkVbWL2Q1U TQ8go8GEExVsEcQ1iQssyycFtu6zp8qfIX9cET4Ad/JkSot9mZLXX9sV5zuj7ieTiuVu Ow6XGezEcnfUWeaQj1GuL1JDp7KZ+445FTeC3oucPF/XF65sEGqna9UgUaRvN66/uhqU mXs2TLkjpYzInYujHoCBGGTXg+yf/S0DF2yovkhWgtu78Kpj08ZhHFudxCBTs5BNBPvR Wezw== X-Gm-Message-State: AAQBX9dfZKmFoK9yrZTofN5kMaI+eA79oY2raLhhvONBhEhk+zfN++/w phvh17H3h4K4ccYfGKccu3UKOg== X-Received: by 2002:a05:6a20:3baa:b0:d8:c9f3:5107 with SMTP id b42-20020a056a203baa00b000d8c9f35107mr10330888pzh.18.1681114344846; Mon, 10 Apr 2023 01:12:24 -0700 (PDT) Received: from C02G87K0MD6R.bytedance.net ([139.177.225.228]) by smtp.gmail.com with ESMTPSA id m17-20020aa79011000000b0062d8e79ea22sm7234100pfo.40.2023.04.10.01.12.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Apr 2023 01:12:24 -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 1/2] sched/core: Fixed missing rq clock update before calling set_rq_offline() Date: Mon, 10 Apr 2023 16:12:05 +0800 Message-Id: <20230410081206.23441-2-jiahao.os@bytedance.com> X-Mailer: git-send-email 2.37.0 (Apple Git-136) In-Reply-To: <20230410081206.23441-1-jiahao.os@bytedance.com> References: <20230410081206.23441-1-jiahao.os@bytedance.com> MIME-Version: 1.0 X-Spam-Status: No, score=-0.2 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1762776753148752300?= X-GMAIL-MSGID: =?utf-8?q?1762776753148752300?= This is triggered during cpu offline when CONFIG_CPU_FREQ is enabled: ------------[ 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 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 --- 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 051aaf65c749..017f7583f0e2 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); From patchwork Mon Apr 10 08:12:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hao Jia X-Patchwork-Id: 81386 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:b0ea:0:b0:3b6:4342:cba0 with SMTP id b10csp1749713vqo; Mon, 10 Apr 2023 01:21:07 -0700 (PDT) X-Google-Smtp-Source: AKy350Y6LBSN+nEif+q0i24Fid6aTrfVjkXszrwi5NLR6hkEjj7Yakom1tCdzlFiJYE2gDc8xwed X-Received: by 2002:a17:902:ca81:b0:19e:6e00:4676 with SMTP id v1-20020a170902ca8100b0019e6e004676mr6358875pld.61.1681114867306; Mon, 10 Apr 2023 01:21:07 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1681114867; cv=none; d=google.com; s=arc-20160816; b=TEaCsEucwbhTMEHBO0SU1+WaQdIpuPiX4CE+wb79XRU6kl6/+MVaJ7c0BFVVMKxWZ0 GBSl2NcTkc8cKHr1BEQFkbPkbyESBlerT28jV4Vn9YyJXmyWYDYwO4tCM2Yd4sSrBN74 RJz0jEfDU3CqCp2LkNLVO9bZMAodMeDH/eA2IrTDiql7e0TuvvVrWbuFREcylqilLtCF /yIqvFhGbEp372qlMN0gTDsdob+Womy9i+0Y3cEya9LxczXAX/ZaXDJeoGSox5pq68QJ 4Yope+FlJ53ZwILTv428X7KUT9HVGk5pbvUUvjOzhkZzPSk8LqJuJoBXWVjJZJQam6Ot iNgQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=LXKYnMeADE56pOVc+eJfLgMquSBzuNugVw1G2HDPE+s=; b=mvRck2PDNT2BM73m1DFfaCDeliN/6KA7O2MWRQeH+yBeqnqsolYsoGBwoDk41F6Zej Zc0/CxY1Ny2RbweXNpRc1GIhSE0WvDlsIJY3H5nMLsFhUf2KcQprb0H+ECxy+4+whZUi NnVsT76jY8XiH1PbMEPZ+V0kLxzCb7ziwzMuFGPlf5Gg3hBeqP1WptuvjtPH4w8M1P0R TlclXnzJBtShvsV5zyK5qgO3ADdvd18VOtbpzT949xqrYGWK9L89Qkev7SewZUjK4JY3 o4djnFIZntjSORjupGaNk5CxSbRk2VuwR1CrejD5f3ac/t8MU7jjiH+WeBet6H1DmeJg Md0Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@bytedance.com header.s=google header.b="I/1CNnYM"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=bytedance.com Received: from out1.vger.email (out1.vger.email. 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migration_cpu_stop+0x2a0/0x2a0 cpu_stopper_thread+0xa3/0x140 smpboot_thread_fn+0x14f/0x210 ? sort_range+0x20/0x20 kthread+0xe6/0x110 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 ------------[ cut here ]------------ rq->clock_update_flags & RQCF_UPDATED WARNING: CPU: 54 PID: 0 at kernel/sched/core.c:741 update_rq_clock+0xaf/0x180 Call Trace: unthrottle_cfs_rq+0x4b/0x300 __cfsb_csd_unthrottle+0xe0/0x100 __flush_smp_call_function_queue+0xaf/0x1d0 flush_smp_call_function_queue+0x49/0x90 do_idle+0x17c/0x270 cpu_startup_entry+0x19/0x20 start_secondary+0xfa/0x120 secondary_startup_64_no_verify+0xce/0xdb ------------[ cut here ]------------ rq->clock_update_flags & RQCF_UPDATED WARNING: CPU: 0 PID: 3323 at kernel/sched/core.c:741 update_rq_clock+0xaf/0x180 Call Trace: unthrottle_cfs_rq+0x4b/0x300 rq_offline_fair+0x89/0x90 set_rq_offline.part.118+0x28/0x60 rq_attach_root+0xc4/0xd0 cpu_attach_domain+0x3dc/0x7f0 partition_sched_domains_locked+0x2a5/0x3c0 rebuild_sched_domains_locked+0x477/0x830 rebuild_sched_domains+0x1b/0x30 cpuset_hotplug_workfn+0x2ca/0xc90 ? balance_push+0x56/0xf0 ? _raw_spin_unlock+0x15/0x30 ? finish_task_switch+0x98/0x2f0 ? __switch_to+0x291/0x410 ? __schedule+0x65e/0x1310 process_one_work+0x1bc/0x3d0 worker_thread+0x4c/0x380 ? preempt_count_add+0x92/0xa0 ? rescuer_thread+0x310/0x310 kthread+0xe6/0x110 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x1f/0x30 For the __balance_push_cpu_stop() case, we remove update_rq_clock() from the __migrate_task() function to avoid double updating the rq clock. And in order to avoid missing rq clock update, add update_rq_clock() call before migration_cpu_stop() calls __migrate_task(). This also works for unthrottle_cfs_rq(), so we also removed update_rq_clock() from the unthrottle_cfs_rq() function to avoid warnings caused by calling it multiple times, such as __cfsb_csd_unthrottle() and unthrottle_offline_cfs_rqs(). and in order to avoid missing rq clock update, we correspondingly add update_rq_clock() calls before unthrottle_cfs_rq() runs. Note that the rq clock has been updated before the set_rq_offline() function runs, so we don't need to add update_rq_clock() call in unthrottle_offline_cfs_rqs(). Signed-off-by: Hao Jia --- kernel/sched/core.c | 11 +++++++---- kernel/sched/fair.c | 9 ++++++--- 2 files changed, 13 insertions(+), 7 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0d18c3969f90..c1abd88ec1ed 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2376,7 +2376,6 @@ static struct rq *__migrate_task(struct rq *rq, struct rq_flags *rf, if (!is_cpu_allowed(p, dest_cpu)) return rq; - update_rq_clock(rq); rq = move_queued_task(rq, rf, p, dest_cpu); return rq; @@ -2434,10 +2433,12 @@ static int migration_cpu_stop(void *data) goto out; } - if (task_on_rq_queued(p)) + if (task_on_rq_queued(p)) { + update_rq_clock(rq); rq = __migrate_task(rq, &rf, p, arg->dest_cpu); - else + } else { p->wake_cpu = arg->dest_cpu; + } /* * XXX __migrate_task() can fail, at which point we might end @@ -10759,8 +10760,10 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota, cfs_rq->runtime_enabled = runtime_enabled; cfs_rq->runtime_remaining = 0; - if (cfs_rq->throttled) + if (cfs_rq->throttled) { + update_rq_clock(rq); unthrottle_cfs_rq(cfs_rq); + } rq_unlock_irq(rq, &rf); } if (runtime_was_enabled && !runtime_enabled) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 6986ea31c984..03ced34e992e 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5438,8 +5438,6 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq) cfs_rq->throttled = 0; - update_rq_clock(rq); - raw_spin_lock(&cfs_b->lock); cfs_b->throttled_time += rq_clock(rq) - cfs_rq->throttled_clock; list_del_rcu(&cfs_rq->throttled_list); @@ -5518,6 +5516,7 @@ static void __cfsb_csd_unthrottle(void *arg) struct rq_flags rf; rq_lock(rq, &rf); + update_rq_clock(rq); /* * Since we hold rq lock we're safe from concurrent manipulation of @@ -5547,6 +5546,7 @@ static inline void __unthrottle_cfs_rq_async(struct cfs_rq *cfs_rq) bool first; if (rq == this_rq()) { + update_rq_clock(rq); unthrottle_cfs_rq(cfs_rq); return; } @@ -5563,6 +5563,7 @@ static inline void __unthrottle_cfs_rq_async(struct cfs_rq *cfs_rq) #else static inline void __unthrottle_cfs_rq_async(struct cfs_rq *cfs_rq) { + update_rq_clock(rq_of(cfs_rq)); unthrottle_cfs_rq(cfs_rq); } #endif @@ -5640,8 +5641,10 @@ static bool distribute_cfs_runtime(struct cfs_bandwidth *cfs_b) if (local_unthrottle) { rq = cpu_rq(this_cpu); rq_lock_irqsave(rq, &rf); - if (cfs_rq_throttled(local_unthrottle)) + if (cfs_rq_throttled(local_unthrottle)) { + update_rq_clock(rq); unthrottle_cfs_rq(local_unthrottle); + } rq_unlock_irqrestore(rq, &rf); }