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[2620:137:e000::1:20]) by mx.google.com with ESMTP id s8-20020a170902ea0800b001ae4d1c1288si625025plg.279.2023.06.07.23.42.24; Wed, 07 Jun 2023 23:42:39 -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=J2eRYyxc; 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 S234750AbjFHGeF (ORCPT + 99 others); Thu, 8 Jun 2023 02:34:05 -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-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 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham 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?1768115730118127800?= X-GMAIL-MSGID: =?utf-8?q?1768115730118127800?= 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); From patchwork Thu Jun 8 06:33:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hao Jia X-Patchwork-Id: 104833 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp84390vqr; Wed, 7 Jun 2023 23:47:04 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ49chqedZudnLacpmytP30neZB0OhRQtW95T1Et+zFdRtvv0CPY9M1yUAJyS+VVIM5lJ02d X-Received: by 2002:a17:90a:19d6:b0:259:3cf3:f6f2 with SMTP id 22-20020a17090a19d600b002593cf3f6f2mr7030168pjj.4.1686206824481; Wed, 07 Jun 2023 23:47:04 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686206824; cv=none; d=google.com; s=arc-20160816; b=GqJkfFPCIDmMQRv+PEV9KKXGYUn6sWsio+TSG3GLqhmM8F2YCNn5TLJlKbfifv1Pe9 sMY6B2MnbBqmLW36MuQY7HyrBQjTSP6/gA6qZt/pFjenuSJev/euXGRCMF7VyAxWY9Aq hIBIvTU0eE0qdI1LjNQ0Lhsoo3DfzsJb6EEl95Toco+8Wbgn56bHCUP5b8DeHXaoQPf7 cGHBxgYlrRWBN1I2HrSxZ+K91vIHVkbDVZBFFIM456ztxGizMPst7dtFnlrekwaNSPVC ZZ2Co1P582GnG+ZEl0OOVKHZ8ZIEuhoiN829VSSuPQk3CjS5OUGNLFs/c7Vx3+lp7vjY 5T+A== 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=nwSmBGENtB9L+r5dkVtr2aEZeow7KKO4JZwDEcpVetc=; b=vI9ZY+lJPnJI0uKWuFft1J+ykUmlpNlkgkzCsUlhaQAHl12PwcFk/lLgXT71+5nQ85 UG48SFlHMxsOjC06SSrUEz0Yf96Q554OZJGCiLhFPTTwltyfXQn+Pyc8epHbP0/24feK l2T7XECHn0OKhkkfUGS15yKK7LXJK+aAa+f/mNX0hBQP7qkOZlj7emj1sqk6Hl6R93Ix guJ71Lxvb1w1biT5bRByUjNNNUxjYQmiY74qZOvOTntxClnKWbWYT7HNREV/REkqTt47 +RtXpRllpFxrxOuKHsvg0aIrs0PzcGvWvHCZqw3nX2fZo+sz2PfIrCOMFrgBBtvf+Ybt c2iw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@bytedance.com header.s=google header.b=IEHwjTXz; 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 To avoid this warning, we remove update_rq_clock() from the __migrate_task() function. And in order to avoid missing rq clock update, add update_rq_clock() call before migration_cpu_stop() calls __migrate_task(). Signed-off-by: Hao Jia Reviewed-by: Vincent Guittot --- kernel/sched/core.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a68d1276bab0..1fd87657f521 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2398,7 +2398,6 @@ 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; @@ -2456,10 +2455,12 @@ 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 From patchwork Thu Jun 8 06:33:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hao Jia X-Patchwork-Id: 104836 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp88889vqr; Wed, 7 Jun 2023 23:59:35 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ597ecLhpuuDDBRdgtaZ+WDq8KssEGtnlAhRCEm0T0W9MCquAYQDb2kvk4zqbSVuaxpau+N X-Received: by 2002:a05:6358:bba5:b0:129:be5b:fff with SMTP id df37-20020a056358bba500b00129be5b0fffmr6146148rwb.9.1686207575444; Wed, 07 Jun 2023 23:59:35 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686207575; cv=none; d=google.com; s=arc-20160816; b=n+NXMMj10gbvg1qxikJzOw9sR6qloF2HsNbo+Hypc+9aIOdhXIkwN+6/ntltZ2KQg4 6crXdk3wJGK0okOZ1L0tg85aVSULlH9Kd/ERPlOHLFt1eOtkn/RlZXBAjTLTFP4sjm+C 846JrPsbvIkIjFehzHLSKpFQBYm80ECzQkGUAu/0tF0kUutdCq3kJMJ7I97p+83QDMGH Adm3iy98vCttAHjBbeksDddDXmxMspGl9hHrMT5VGf7aJDwEbiVKpU56RJJJ68tAj/uA kaECFVpA3OGe0GKDju8o0KHhX4oiLJDPGPdStN1sLzPPphqhER5YwfLsseKex2GaxwOF fqSQ== 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=/kiXdCNBs7MsEGE9ZtEtEzwmLWhy0ZFEY2zGjq+a+7k=; b=sWvLEpEXVRR8N2tmN6wd2uO82SSWbN3pHZyjyTWgJAYVHNj11cNWMYtUT/jWIwtJRs s21qrsBXabzSbM8ePLbwLtwm1AyVfOuk9NvytNv1syunoFltB2kkn6Q3TCEPq6LSrhV6 i6FUDQ1Ub2L1HCYGKgYUNz3JqLjWqpaURAd6NQZcdaoLCrCg8uhyeProWT3ZSklXgOAL SV24fgiDahlICFbbIoHVy9rT4fxbVx/d6YireGAyx9zr2AHYq+YM5rokncPapkq7MX2M hdQR6sTvbe5tzJgx6zCdG4pPQn1uISW0QAb+wNPTbrVHYYu+AwL5T8ORYjA1LkHBxP8D LO+Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@bytedance.com header.s=google header.b=jBkNXeny; 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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At that time the following warning will be triggered. ------------[ 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 Before the loop starts, we update the rq clock once and call rq_clock_start_loop_update() to prevent updating the rq clock multiple times. And call rq_clock_stop_loop_update() After the loop to clear rq->clock_update_flags. Fixes: 8ad075c2eb1f ("sched: Async unthrottling for cfs bandwidth") Suggested-by: Vincent Guittot Signed-off-by: Hao Jia Reviewed-by: Vincent Guittot --- kernel/sched/fair.c | 9 +++++++++ kernel/sched/sched.h | 21 +++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 373ff5f55884..af9604f4b135 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5576,6 +5576,14 @@ static void __cfsb_csd_unthrottle(void *arg) rq_lock(rq, &rf); + /* + * Iterating over the list can trigger several call to + * update_rq_clock() in unthrottle_cfs_rq(). + * Do it once and skip the potential next ones. + */ + update_rq_clock(rq); + rq_clock_start_loop_update(rq); + /* * Since we hold rq lock we're safe from concurrent manipulation of * the CSD list. However, this RCU critical section annotates the @@ -5595,6 +5603,7 @@ static void __cfsb_csd_unthrottle(void *arg) rcu_read_unlock(); + rq_clock_stop_loop_update(rq); rq_unlock(rq, &rf); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index ec7b3e0a2b20..50446e401b9f 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1546,6 +1546,27 @@ static inline void rq_clock_cancel_skipupdate(struct rq *rq) rq->clock_update_flags &= ~RQCF_REQ_SKIP; } +/* + * During cpu offlining and rq wide unthrottling, we can trigger + * an update_rq_clock() for several cfs and rt runqueues (Typically + * when using list_for_each_entry_*) + * rq_clock_start_loop_update() can be called after updating the clock + * once and before iterating over the list to prevent multiple update. + * After the iterative traversal, we need to call rq_clock_stop_loop_update() + * to clear RQCF_ACT_SKIP of rq->clock_update_flags. + */ +static inline void rq_clock_start_loop_update(struct rq *rq) +{ + lockdep_assert_rq_held(rq); + rq->clock_update_flags |= RQCF_ACT_SKIP; +} + +static inline void rq_clock_stop_loop_update(struct rq *rq) +{ + lockdep_assert_rq_held(rq); + rq->clock_update_flags &= ~RQCF_ACT_SKIP; +} + struct rq_flags { unsigned long flags; struct pin_cookie cookie; From patchwork Thu Jun 8 06:33:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hao Jia X-Patchwork-Id: 104835 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp87643vqr; Wed, 7 Jun 2023 23:56:16 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ4HNY+Nbf6Yj9bPZesde2sLboKmeemhyUTJV++32E3zUcegBCVS8PuVVE5pEAMAZc7AakKZ X-Received: by 2002:a05:6358:cc22:b0:129:df95:f9a9 with SMTP id gx34-20020a056358cc2200b00129df95f9a9mr6211177rwb.2.1686207375642; Wed, 07 Jun 2023 23:56:15 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1686207375; cv=none; d=google.com; s=arc-20160816; b=I3XcI6QhXUi/qq/bPD/5Q4Woltf3pY0wbd+lCReSrd6IwF1f/Ky0U/naua6479wVW9 fCvbFeJmoStZJB5fiVONrn6rnGIOdVY9OOQLd8QfKqgJDbIRyX0AWRarEqRe3WDaN2Uu PspUsZpGhhLiFlEw2jGZ9HrDmpRi0hYlanF0vt/V0+Tuz/nw5qdGS+5Pf2pYoUqwlP6S DDUpSqk3cz6NWiJQOwLOLpNigjH2ctXAj72d1Y14ht3Utso/ZQ9AAou/11NHqlVrfOJd NYpeD6NX6piour2rmAgX+UecuJH+QMqQ8ws1zIFEkOblsyozAmtSwseGUQ+ohrTHqXVR 4eQg== 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=1YqsjZstkNId62swixNvbney3wfAymRF6traYgOxlKU=; b=mmSclxaPe6pPhUZItYZs+jGXsm/XEdnXHgefeubff0U/XpbbwaZ8oCi2GIjUClOfH3 dtck96xvNxjOx5Y/rr5ue6DGvjEUmMSRmsl2iCyTYPYsJ/1/2F0saRSYpJ+nBAiEJOa2 LUTvRBeV8P/uDTYkWJyuplw1hytAE8UiNO3dW6VfWAxvGEoED1rwVoIHLN/v4mENDv/m bViVx/D2RQnnNS5Jzp1Wv6s13p/nEgqSRR9+on6esCl2UYF1j9Ql3LS5N8LCg8aR43Wc Ydgzi3MsCM8HRWF6q1JPid9ZVLAkqB/5MmOyGpNTZfpBmAjPFYTmFnE+eJtexfxvUFG9 hElw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@bytedance.com header.s=google header.b=VvAzPvj6; 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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Wed, 07 Jun 2023 23:33:52 -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 4/4] sched/core: Avoid multiple calling update_rq_clock() in unthrottle_offline_cfs_rqs() Date: Thu, 8 Jun 2023 14:33:12 +0800 Message-Id: <20230608063312.79440-5-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 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham 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?1768116585104365923?= X-GMAIL-MSGID: =?utf-8?q?1768116585104365923?= This WARN_DOUBLE_CLOCK warning is triggered during cpu offline. ------------[ 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 The rq clock has been updated before the set_rq_offline() function runs, so we don't need to call update_rq_clock() in unthrottle_offline_cfs_rqs(). We only need to call rq_clock_start_loop_update() before the loop starts and rq_clock_stop_loop_update() after the loop to avoid this warning. Suggested-by: Vincent Guittot Signed-off-by: Hao Jia Reviewed-by: Vincent Guittot --- kernel/sched/fair.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index af9604f4b135..9e961e0ec971 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6124,6 +6124,13 @@ static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq) lockdep_assert_rq_held(rq); + /* + * The rq clock has already been updated before the + * set_rq_offline() runs, so we should skip updating + * the rq clock again in unthrottle_cfs_rq(). + */ + rq_clock_start_loop_update(rq); + rcu_read_lock(); list_for_each_entry_rcu(tg, &task_groups, list) { struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)]; @@ -6146,6 +6153,8 @@ static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq) unthrottle_cfs_rq(cfs_rq); } rcu_read_unlock(); + + rq_clock_stop_loop_update(rq); } #else /* CONFIG_CFS_BANDWIDTH */