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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 E819DC07E85 for ; Fri, 7 Dec 2018 20:20:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A92192083D for ; Fri, 7 Dec 2018 20:20:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A92192083D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726165AbeLGUU5 (ORCPT ); Fri, 7 Dec 2018 15:20:57 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:53736 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726078AbeLGUU5 (ORCPT ); Fri, 7 Dec 2018 15:20:57 -0500 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 B743C15AB; Fri, 7 Dec 2018 12:20:56 -0800 (PST) Received: from [10.1.194.37] (e113632-lin.cambridge.arm.com [10.1.194.37]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5A2F43F614; Fri, 7 Dec 2018 12:20:54 -0800 (PST) Subject: Re: [PATCH v4 04/10] sched/fair: Dynamically update cfs_overload_cpus To: Steve Sistare , mingo@redhat.com, peterz@infradead.org Cc: subhra.mazumdar@oracle.com, dhaval.giani@oracle.com, daniel.m.jordan@oracle.com, pavel.tatashin@microsoft.com, matt@codeblueprint.co.uk, umgwanakikbuti@gmail.com, riel@redhat.com, jbacik@fb.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, quentin.perret@arm.com, linux-kernel@vger.kernel.org References: <1544131696-2888-1-git-send-email-steven.sistare@oracle.com> <1544131696-2888-5-git-send-email-steven.sistare@oracle.com> From: Valentin Schneider Message-ID: <3ec57357-dc4e-be1b-963f-abcf760ecc5a@arm.com> Date: Fri, 7 Dec 2018 20:20:52 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1544131696-2888-5-git-send-email-steven.sistare@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Steve, On 06/12/2018 21:28, Steve Sistare wrote: [...] > @@ -3724,6 +3725,28 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq) > rq->misfit_task_load = task_h_load(p); > } > > +static void overload_clear(struct rq *rq) Nitpicky nit: cfs_overload_{clear, set} might be a bit better, just to explicitly differentiate this from rq->rd->overload. Although I suppose the naming problem will show up again if/when you try to expand this to other classes... > +{ > + struct sparsemask *overload_cpus; > + > + rcu_read_lock(); > + overload_cpus = rcu_dereference(rq->cfs_overload_cpus); > + if (overload_cpus) > + sparsemask_clear_elem(overload_cpus, rq->cpu); > + rcu_read_unlock(); > +} > + > +static void overload_set(struct rq *rq) > +{ > + struct sparsemask *overload_cpus; > + > + rcu_read_lock(); > + overload_cpus = rcu_dereference(rq->cfs_overload_cpus); > + if (overload_cpus) > + sparsemask_set_elem(overload_cpus, rq->cpu); > + rcu_read_unlock(); > +} > + > #else /* CONFIG_SMP */ > > #define UPDATE_TG 0x0 [...] > @@ -4468,8 +4495,12 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq) > dequeue = 0; > } > > - if (!se) > + if (!se) { > sub_nr_running(rq, task_delta); > + if (prev_nr >= 2 && prev_nr - task_delta < 2) > + overload_clear(rq); > + > + } Eventually it'd be nice to squash those into {add, sub}_nr_running(), but you already mentioned wanting to stick to CFS for now, so I don't think it's *too* much of a big deal. > > cfs_rq->throttled = 1; > cfs_rq->throttled_clock = rq_clock(rq); > @@ -4499,6 +4530,7 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq) [...]