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[209.132.180.67]) by mx.google.com with ESMTP id 13-v6si1706943plb.463.2018.06.26.06.53.29; Tue, 26 Jun 2018 06:53:29 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=D50XeQYz; spf=pass (google.com: best guess record for domain of stable-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=stable-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935546AbeFZNx2 (ORCPT + 13 others); Tue, 26 Jun 2018 09:53:28 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:43454 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935524AbeFZNx1 (ORCPT ); Tue, 26 Jun 2018 09:53:27 -0400 Received: by mail-wr0-f193.google.com with SMTP id c5-v6so6204244wrs.10 for ; Tue, 26 Jun 2018 06:53:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Ln7vsS0dfsTTzXFg4JBDtoiAgEs1GAAAga1CPUIRcMk=; b=D50XeQYzkbwpfjRimneloVYeY3Wr839MYDRsdaqFNpUAobnm4Pud9VscMUm6NAZsZx ZniIC33Oq/wt7AyLbmZScNHtQzbz+xQBc1dvJOBciGgZgOzyLU8Du+PePS3CbiMLtOaL b85byEfmWwxxnGgBJY61v4jccdF/Hzi/2+ruc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Ln7vsS0dfsTTzXFg4JBDtoiAgEs1GAAAga1CPUIRcMk=; b=K8G3q4M84ZrjiKT3R9khO2wvJAiH5DFBlHibhbl04o2q5J2jRaFtXTQHBPGWa6hDJT NRmN3zhxo8PuZ6CsnXipXlTiGiF4obLUZDfb/Z6Z60TCuxW+I8t6oU5aOkMgFFC3M+DG tOoNZWgu07f8GBTlehhTlcdGzoWDduwDYqgZC131EotZk4/g9SOHLCbGQ6R+pKrgWERI OjGqZSvgmVzyBAeQ4XV2xgtb/HsovH3Ro2R4WkpPWB25ELat747eEQpD0UXMFWVATjWQ mVqp6n0O8p61s2qCG2wGkEmCHnFfKa8PdsximDumtZaIEx2F9LOiSZGoxNjbmz5VcawH PIZA== X-Gm-Message-State: APt69E1pPh1ch8EVgnwD6n8lvy9w+1E/J1hW0bgrAxiDtDcdpdn4ivkv P3W5+ZKMeco9AlC6mUvkGDpGqg== X-Received: by 2002:adf:99ea:: with SMTP id y97-v6mr1571971wrb.215.1530021205827; Tue, 26 Jun 2018 06:53:25 -0700 (PDT) Received: from localhost.localdomain ([2a01:e0a:f:6020:9d92:4c1a:6154:250c]) by smtp.gmail.com with ESMTPSA id 189-v6sm2855835wmd.17.2018.06.26.06.53.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 26 Jun 2018 06:53:25 -0700 (PDT) From: Vincent Guittot To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org Cc: patrick.bellasi@arm.com, viresh.kumar@linaro.org, tglx@linutronix.de, efault@gmx.de, juri.lelli@redhat.com, Vincent Guittot , "# v4 . 16+" Subject: [PATCH v2] sched/rt: fix call to cpufreq_update_util Date: Tue, 26 Jun 2018 15:53:22 +0200 Message-Id: <1530021202-21695-1-git-send-email-vincent.guittot@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: References: Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org With commit 8f111bc357aa ("cpufreq/schedutil: Rewrite CPUFREQ_RT support") schedutil governor uses rq->rt.rt_nr_running to detect whether a RT task is currently running on the CPU and to set frequency to max if necessary. cpufreq_update_util() is called in enqueue/dequeue_top_rt_rq() but rq->rt.rt_nr_running has not been updated yet when dequeue_top_rt_rq() is called so schedutil still considers that a RT task is running when the last task is dequeued. The update of rq->rt.rt_nr_running happens later in dequeue_rt_stack(). In fact, we can take advantage of the sequence that the dequeue then re-enqueue rt entities when a rt task is enqueued or dequeued; As a result enqueue_top_rt_rq() is always called when a task is enqueued or dequeued and also when groups are throttled or unthrottled. The only place that not use enqueue_top_rt_rq() is when root rt_rq is throttled. Fixes: 8f111bc357aa ('cpufreq/schedutil: Rewrite CPUFREQ_RT support') Cc: # v4.16+ Signed-off-by: Vincent Guittot --- kernel/sched/cpufreq_schedutil.c | 2 +- kernel/sched/rt.c | 16 ++++++++++------ kernel/sched/sched.h | 5 +++++ 3 files changed, 16 insertions(+), 7 deletions(-) -- 2.7.4 diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 3cde464..c907fde 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -192,7 +192,7 @@ static unsigned long sugov_aggregate_util(struct sugov_cpu *sg_cpu) { struct rq *rq = cpu_rq(sg_cpu->cpu); - if (rq->rt.rt_nr_running) + if (rt_rq_is_runnable(&rq->rt)) return sg_cpu->max; /* diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 47556b0..5725670 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -508,8 +508,11 @@ static void sched_rt_rq_dequeue(struct rt_rq *rt_rq) rt_se = rt_rq->tg->rt_se[cpu]; - if (!rt_se) + if (!rt_se) { dequeue_top_rt_rq(rt_rq); + /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ + cpufreq_update_util(rq_of_rt_rq(rt_rq), 0); + } else if (on_rt_rq(rt_se)) dequeue_rt_entity(rt_se, 0); } @@ -1001,8 +1004,6 @@ dequeue_top_rt_rq(struct rt_rq *rt_rq) sub_nr_running(rq, rt_rq->rt_nr_running); rt_rq->rt_queued = 0; - /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ - cpufreq_update_util(rq, 0); } static void @@ -1014,11 +1015,14 @@ enqueue_top_rt_rq(struct rt_rq *rt_rq) if (rt_rq->rt_queued) return; - if (rt_rq_throttled(rt_rq) || !rt_rq->rt_nr_running) + + if (rt_rq_throttled(rt_rq)) return; - add_nr_running(rq, rt_rq->rt_nr_running); - rt_rq->rt_queued = 1; + if (rt_rq->rt_nr_running) { + add_nr_running(rq, rt_rq->rt_nr_running); + rt_rq->rt_queued = 1; + } /* Kick cpufreq (see the comment in kernel/sched/sched.h). */ cpufreq_update_util(rq, 0); diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 6601baf..27ddec3 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -609,6 +609,11 @@ struct rt_rq { #endif }; +static inline bool rt_rq_is_runnable(struct rt_rq *rt_rq) +{ + return rt_rq->rt_queued && rt_rq->rt_nr_running; +} + /* Deadline class' related fields in a runqueue */ struct dl_rq { /* runqueue is an rbtree, ordered by deadline */