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=-10.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 8BED7C433DF for ; Tue, 30 Jun 2020 11:22:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75A50206E9 for ; Tue, 30 Jun 2020 11:22:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732940AbgF3LWL (ORCPT ); Tue, 30 Jun 2020 07:22:11 -0400 Received: from foss.arm.com ([217.140.110.172]:40914 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726931AbgF3LWI (ORCPT ); Tue, 30 Jun 2020 07:22:08 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 141B331B; Tue, 30 Jun 2020 04:22:08 -0700 (PDT) Received: from e107158-lin.cambridge.arm.com (e107158-lin.cambridge.arm.com [10.1.195.21]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 49B593F68F; Tue, 30 Jun 2020 04:22:06 -0700 (PDT) From: Qais Yousef To: Ingo Molnar , Peter Zijlstra Cc: Valentin Schneider , Qais Yousef , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Patrick Bellasi , Chris Redpath , Lukasz Luba , linux-kernel@vger.kernel.org Subject: [PATCH v6 1/2] sched/uclamp: Fix initialization of struct uclamp_rq Date: Tue, 30 Jun 2020 12:21:22 +0100 Message-Id: <20200630112123.12076-2-qais.yousef@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200630112123.12076-1-qais.yousef@arm.com> References: <20200630112123.12076-1-qais.yousef@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org struct uclamp_rq was zeroed out entirely in assumption that in the first call to uclamp_rq_inc() they'd be initialized correctly in accordance to default settings. But when next patch introduces a static key to skip uclamp_rq_{inc,dec}() until userspace opts in to use uclamp, schedutil will fail to perform any frequency changes because the rq->uclamp[UCLAMP_MAX].value is zeroed at init and stays as such. Which means all rqs are capped to 0 by default. Fix it by making sure we do proper initialization at init without relying on uclamp_rq_inc() doing it later. Fixes: 69842cba9ace ("sched/uclamp: Add CPU's clamp buckets refcounting") Reviewed-by: Valentin Schneider Signed-off-by: Qais Yousef Cc: Juri Lelli Cc: Vincent Guittot Cc: Dietmar Eggemann Cc: Steven Rostedt Cc: Ben Segall Cc: Mel Gorman CC: Patrick Bellasi Cc: Chris Redpath Cc: Lukasz Luba Cc: linux-kernel@vger.kernel.org --- kernel/sched/core.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8fe2ac910bed..235b2cae00a0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1248,6 +1248,20 @@ static void uclamp_fork(struct task_struct *p) } } +static void __init init_uclamp_rq(struct rq *rq) +{ + enum uclamp_id clamp_id; + struct uclamp_rq *uc_rq = rq->uclamp; + + for_each_clamp_id(clamp_id) { + uc_rq[clamp_id] = (struct uclamp_rq) { + .value = uclamp_none(clamp_id) + }; + } + + rq->uclamp_flags = 0; +} + static void __init init_uclamp(void) { struct uclamp_se uc_max = {}; @@ -1256,11 +1270,8 @@ static void __init init_uclamp(void) mutex_init(&uclamp_mutex); - for_each_possible_cpu(cpu) { - memset(&cpu_rq(cpu)->uclamp, 0, - sizeof(struct uclamp_rq)*UCLAMP_CNT); - cpu_rq(cpu)->uclamp_flags = 0; - } + for_each_possible_cpu(cpu) + init_uclamp_rq(cpu_rq(cpu)); for_each_clamp_id(clamp_id) { uclamp_se_set(&init_task.uclamp_req[clamp_id], -- 2.17.1