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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 024D2C04E53 for ; Wed, 15 May 2019 09:46:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D25C320862 for ; Wed, 15 May 2019 09:46:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726855AbfEOJqX (ORCPT ); Wed, 15 May 2019 05:46:23 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:39480 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725974AbfEOJqW (ORCPT ); Wed, 15 May 2019 05:46:22 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2283AA78; Wed, 15 May 2019 02:46:22 -0700 (PDT) Received: from e110439-lin.cambridge.arm.com (e110439-lin.cambridge.arm.com [10.1.194.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 0AE6C3F703; Wed, 15 May 2019 02:46:18 -0700 (PDT) From: Patrick Bellasi To: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-api@vger.kernel.org Cc: Ingo Molnar , Peter Zijlstra , Tejun Heo , "Rafael J . Wysocki" , Vincent Guittot , Viresh Kumar , Paul Turner , Quentin Perret , Dietmar Eggemann , Morten Rasmussen , Juri Lelli , Todd Kjos , Joel Fernandes , Steve Muckle , Suren Baghdasaryan Subject: [PATCH v9 15/16] sched/core: uclamp: Use TG's clamps to restrict TASK's clamps Date: Wed, 15 May 2019 10:44:58 +0100 Message-Id: <20190515094459.10317-16-patrick.bellasi@arm.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190515094459.10317-1-patrick.bellasi@arm.com> References: <20190515094459.10317-1-patrick.bellasi@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a task specific clamp value is configured via sched_setattr(2), this value is accounted in the corresponding clamp bucket every time the task is {en,de}qeued. However, when cgroups are also in use, the task specific clamp values could be restricted by the task_group (TG) clamp values. Update uclamp_cpu_inc() to aggregate task and TG clamp values. Every time a task is enqueued, it's accounted in the clamp_bucket defining the smaller clamp between the task specific value and its TG effective value. This allows to: 1. ensure cgroup clamps are always used to restrict task specific requests, i.e. boosted only up to the effective granted value or clamped at least to a certain value 2. implement a "nice-like" policy, where tasks are still allowed to request less then what enforced by their current TG This mimics what already happens for a task's CPU affinity mask when the task is also in a cpuset, i.e. cgroup attributes are always used to restrict per-task attributes. Do this by exploiting the concept of "effective" clamp, which is already used by a TG to track parent enforced restrictions. Apply task group clamp restrictions only to tasks belonging to a child group. While, for tasks in the root group or in an autogroup, only system defaults are enforced. Signed-off-by: Patrick Bellasi Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Tejun Heo --- kernel/sched/core.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index bd96a977ed07..354d925a6ba8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -861,16 +861,42 @@ unsigned int uclamp_rq_max_value(struct rq *rq, unsigned int clamp_id, return uclamp_idle_value(rq, clamp_id, clamp_value); } +static inline struct uclamp_se +uclamp_tg_restrict(struct task_struct *p, unsigned int clamp_id) +{ + struct uclamp_se uc_req = p->uclamp_req[clamp_id]; +#ifdef CONFIG_UCLAMP_TASK_GROUP + struct uclamp_se uc_max; + + /* + * Tasks in autogroups or root task group will be + * restricted by system defaults. + */ + if (task_group_is_autogroup(task_group(p))) + return uc_req; + if (task_group(p) == &root_task_group) + return uc_req; + + uc_max = task_group(p)->uclamp[clamp_id]; + if (uc_req.value > uc_max.value || !uc_req.user_defined) + return uc_max; +#endif + + return uc_req; +} + /* * The effective clamp bucket index of a task depends on, by increasing * priority: * - the task specific clamp value, when explicitly requested from userspace + * - the task group effective clamp value, for tasks not either in the root + * group or in an autogroup * - the system default clamp value, defined by the sysadmin */ static inline struct uclamp_se uclamp_eff_get(struct task_struct *p, unsigned int clamp_id) { - struct uclamp_se uc_req = p->uclamp_req[clamp_id]; + struct uclamp_se uc_req = uclamp_tg_restrict(p, clamp_id); struct uclamp_se uc_max = uclamp_default[clamp_id]; /* System default restrictions always apply */ -- 2.21.0