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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 E08E0C48BCD for ; Wed, 9 Jun 2021 14:34:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6CFE613B8 for ; Wed, 9 Jun 2021 14:34:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236549AbhFIOgn (ORCPT ); Wed, 9 Jun 2021 10:36:43 -0400 Received: from mail-qv1-f73.google.com ([209.85.219.73]:38821 "EHLO mail-qv1-f73.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232165AbhFIOgm (ORCPT ); Wed, 9 Jun 2021 10:36:42 -0400 Received: by mail-qv1-f73.google.com with SMTP id i6-20020a0cd8460000b029022689c68e72so11370264qvj.5 for ; Wed, 09 Jun 2021 07:34:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=ujJ7V2lKU2Osdsi84sTaaJPDcMYpTcXqnHW0Nm4jQfs=; b=sph+9QWdALbk3yu47eGVpi1/fvZe4Sedy3rrMZqi93njEFAlesgGBptGBKECL7kcSi YO8Hw5xh8o0OCRayGVfKNno48LdfeX/gi3dCqbDROQ7weoro1kLyDMXnSTSS2LC+0gSe MN/7D/8ZirGW4FmvA9kwbCTGFZ0Nj0mfnivpJSjTRDXkh0Z5Oscqq+KH6J+lx5fxVRq8 6fN8IbuSTJorJeinL1eoWPn4ouFT7cFTmkb/nFLlbL0V8mOvZyq8OfM3Mh6SsouBqsEY 0CpuKDHgUq8vtJh/rxibRv3h/RUjJXNVcakXVDXqVRgdujQDWZUgS1YsHFXla3qzDU/K ZPrQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=ujJ7V2lKU2Osdsi84sTaaJPDcMYpTcXqnHW0Nm4jQfs=; b=OU+8/LdkywAGe57f+j27fZJJ1zeMTUg0Ob4rveZPvPLaTeb+JLNJntg2qFk4SU/UNU lgRWJm/KL4fO+Y/v8umlEtjhKiH8FB8KBDX+CuJE6ZHsvboYz6Xua0C2FCc7tQa2w1wg 1SzLY5qTYCJIkr+UXbSZJuAr6dOrJLifKoIH0GNJbRKniZy/KAFMB331oPeU+XqARgy/ EsepEeVWNHzqWqbuIvpdg97Vx4D9N2suyHfoOj560ZSfOoWFhE7NZQ0sbfmW8RfjBg9I /Nm+43ZO4Izsq0O0D7bLfFA7NZ2uQyKrJlepY9v+oZrZ0gznPBa1EeXn+Wu+73eQMg6B qTvQ== X-Gm-Message-State: AOAM532lMHfco7cveo3xMexESkj7UYZStuIiC7kbkt6amaeP0uhIPJxV CIMAgtNzvaobMSilR6VKBgD+HX9yPQG9 X-Google-Smtp-Source: ABdhPJxOJ0pHTcYhe0gIXSj7GPNB9Ea02/zFe3+FDrz+GqTcx4sztVdzrwjvtnm1Resx1H2L2Bclo5wR9lyd X-Received: from r2d2-qp.c.googlers.com ([fda3:e722:ac3:cc00:28:9cb1:c0a8:1652]) (user=qperret job=sendgmr) by 2002:ad4:5ba8:: with SMTP id 8mr6045636qvq.25.1623249227196; Wed, 09 Jun 2021 07:33:47 -0700 (PDT) Date: Wed, 9 Jun 2021 14:33:39 +0000 Message-Id: <20210609143339.1194238-1-qperret@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.32.0.272.g935e593368-goog Subject: [PATCH] sched: Fix UCLAMP_FLAG_IDLE setting From: Quentin Perret To: mingo@redhat.com, peterz@infradead.org, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, qais.yousef@arm.com, rickyiu@google.com, wvw@google.com, patrick.bellasi@matbug.net Cc: linux-kernel@vger.kernel.org, kernel-team@android.com, Quentin Perret Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The UCLAMP_FLAG_IDLE flag is set on a runqueue when dequeueing the last active task to maintain the last uclamp.max and prevent blocked util from suddenly becoming visible. However, there is an asymmetry in how the flag is set and cleared which can lead to having the flag set whilst there are active task on the rq. Specifically, the flag is set in the uclamp_rq_inc() path, which is called at enqueue time, but cleared in the uclamp_rq_dec_id() which is called both when dequeueing and task _and_ during cgroup migrations. Fix this by setting the flag in the uclamp_rq_inc_id() path to ensure things remain symmetrical. Reported-by: Rick Yiu Signed-off-by: Quentin Perret --- kernel/sched/core.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 5226cc26a095..3b213402798e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -980,6 +980,7 @@ static inline void uclamp_idle_reset(struct rq *rq, enum uclamp_id clamp_id, if (!(rq->uclamp_flags & UCLAMP_FLAG_IDLE)) return; + rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE; WRITE_ONCE(rq->uclamp[clamp_id].value, clamp_value); } @@ -1252,10 +1253,6 @@ static inline void uclamp_rq_inc(struct rq *rq, struct task_struct *p) for_each_clamp_id(clamp_id) uclamp_rq_inc_id(rq, p, clamp_id); - - /* Reset clamp idle holding when there is one RUNNABLE task */ - if (rq->uclamp_flags & UCLAMP_FLAG_IDLE) - rq->uclamp_flags &= ~UCLAMP_FLAG_IDLE; } static inline void uclamp_rq_dec(struct rq *rq, struct task_struct *p) -- 2.32.0.272.g935e593368-goog