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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 A9BD8C43441 for ; Sun, 11 Nov 2018 16:48:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 63774216FD for ; Sun, 11 Nov 2018 16:48:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="sHsRnEm9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 63774216FD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org 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 S1729254AbeKLChJ (ORCPT ); Sun, 11 Nov 2018 21:37:09 -0500 Received: from merlin.infradead.org ([205.233.59.134]:56710 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728378AbeKLChI (ORCPT ); Sun, 11 Nov 2018 21:37:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=RPBSh1w3SI/Ppyu+2+E9IV871NnwVbPJRYWjthThOw4=; b=sHsRnEm9Zs0g6tsBcY64PDgrJ 2BmWgp6vcGqt4ZzzX52kxGaLHqkiYtv1VnscMMQAbs30d9DteCCt5LU5V6EzIr3AHc7867hkPvl0A RCVlQdJS4xxpivQ4BtAzXA8mpPhmz4HDOxexIZVx1g4pIRkMHOF7oXuGTSql8yQIQESEQO33YbuVT V2yDGYcXr83oXQISUQLvaAqGrQeTZfCiiofxtvJ3o83OPcyZou0byz8MffeKcNuYuhEmJPSrfozIV ppT6lBHFn0d4WVAipqlN6ypIDmJ4SyXq7Offx4kXd7yKUXRawi/XYuElkS0GPniZMAHV93P2jxCga yDYfWleUA==; Received: from [64.114.255.97] (helo=worktop) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gLstx-0000Ai-F9; Sun, 11 Nov 2018 16:47:57 +0000 Received: by worktop (Postfix, from userid 1000) id E93836E061A; Sun, 11 Nov 2018 17:47:54 +0100 (CET) Date: Sun, 11 Nov 2018 17:47:54 +0100 From: Peter Zijlstra To: Patrick Bellasi Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Ingo Molnar , 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: Re: [PATCH v5 04/15] sched/core: uclamp: add CPU's clamp groups refcounting Message-ID: <20181111164754.GA3038@worktop> References: <20181029183311.29175-1-patrick.bellasi@arm.com> <20181029183311.29175-6-patrick.bellasi@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181029183311.29175-6-patrick.bellasi@arm.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 29, 2018 at 06:32:59PM +0000, Patrick Bellasi wrote: > +static inline void uclamp_cpu_update(struct rq *rq, unsigned int clamp_id) > +{ > + unsigned int group_id; > + int max_value = 0; > + > + for (group_id = 0; group_id < UCLAMP_GROUPS; ++group_id) { > + if (!rq->uclamp.group[clamp_id][group_id].tasks) > + continue; > + /* Both min and max clamps are MAX aggregated */ > + if (max_value < rq->uclamp.group[clamp_id][group_id].value) > + max_value = rq->uclamp.group[clamp_id][group_id].value; max_value = max(max_value, rq->uclamp.group[clamp_id][group_id].value); > + if (max_value >= SCHED_CAPACITY_SCALE) > + break; > + } > + rq->uclamp.value[clamp_id] = max_value; > +} > + > +/** > + * uclamp_cpu_get_id(): increase reference count for a clamp group on a CPU > + * @p: the task being enqueued on a CPU > + * @rq: the CPU's rq where the clamp group has to be reference counted > + * @clamp_id: the clamp index to update > + * > + * Once a task is enqueued on a CPU's rq, the clamp group currently defined by > + * the task's uclamp::group_id is reference counted on that CPU. > + */ > +static inline void uclamp_cpu_get_id(struct task_struct *p, struct rq *rq, > + unsigned int clamp_id) > +{ > + unsigned int group_id; > + > + if (unlikely(!p->uclamp[clamp_id].mapped)) > + return; > + > + group_id = p->uclamp[clamp_id].group_id; > + p->uclamp[clamp_id].active = true; > + > + rq->uclamp.group[clamp_id][group_id].tasks += 1; ++ > + > + if (rq->uclamp.value[clamp_id] < p->uclamp[clamp_id].value) > + rq->uclamp.value[clamp_id] = p->uclamp[clamp_id].value; rq->uclamp.value[clamp_id] = max(rq->uclamp.value[clamp_id], p->uclamp[clamp_id].value); > +} > + > +/** > + * uclamp_cpu_put_id(): decrease reference count for a clamp group on a CPU > + * @p: the task being dequeued from a CPU > + * @rq: the CPU's rq from where the clamp group has to be released > + * @clamp_id: the clamp index to update > + * > + * When a task is dequeued from a CPU's rq, the CPU's clamp group reference > + * counted by the task is released. > + * If this was the last task reference coutning the current max clamp group, > + * then the CPU clamping is updated to find the new max for the specified > + * clamp index. > + */ > +static inline void uclamp_cpu_put_id(struct task_struct *p, struct rq *rq, > + unsigned int clamp_id) > +{ > + unsigned int clamp_value; > + unsigned int group_id; > + > + if (unlikely(!p->uclamp[clamp_id].mapped)) > + return; > + > + group_id = p->uclamp[clamp_id].group_id; > + p->uclamp[clamp_id].active = false; > + SCHED_WARN_ON(!rq->uclamp.group[clamp_id][group_id].tasks); > + if (likely(rq->uclamp.group[clamp_id][group_id].tasks)) > + rq->uclamp.group[clamp_id][group_id].tasks -= 1; -- > +#ifdef CONFIG_SCHED_DEBUG > + else { > + WARN(1, "invalid CPU[%d] clamp group [%u:%u] refcount\n", > + cpu_of(rq), clamp_id, group_id); > + } > +#endif > + > + if (likely(rq->uclamp.group[clamp_id][group_id].tasks)) > + return; > + > + clamp_value = rq->uclamp.group[clamp_id][group_id].value; > +#ifdef CONFIG_SCHED_DEBUG > + if (unlikely(clamp_value > rq->uclamp.value[clamp_id])) { > + WARN(1, "invalid CPU[%d] clamp group [%u:%u] value\n", > + cpu_of(rq), clamp_id, group_id); > + } > +#endif SCHED_WARN_ON(clamp_value > rq->uclamp.value[clamp_id]); > + if (clamp_value >= rq->uclamp.value[clamp_id]) > + uclamp_cpu_update(rq, clamp_id); > +} > @@ -866,6 +1020,28 @@ static void uclamp_group_get(struct uclamp_se *uc_se, unsigned int clamp_id, > if (res != uc_map_old.data) > goto retry; > > + /* Ensure each CPU tracks the correct value for this clamp group */ > + if (likely(uc_map_new.se_count > 1)) > + goto done; > + for_each_possible_cpu(cpu) { yuck yuck yuck.. why!? > + struct uclamp_cpu *uc_cpu = &cpu_rq(cpu)->uclamp; > + > + /* Refcounting is expected to be always 0 for free groups */ > + if (unlikely(uc_cpu->group[clamp_id][group_id].tasks)) { > + uc_cpu->group[clamp_id][group_id].tasks = 0; > +#ifdef CONFIG_SCHED_DEBUG > + WARN(1, "invalid CPU[%d] clamp group [%u:%u] refcount\n", > + cpu, clamp_id, group_id); > +#endif SCHED_WARN_ON(); > + } > + > + if (uc_cpu->group[clamp_id][group_id].value == clamp_value) > + continue; > + uc_cpu->group[clamp_id][group_id].value = clamp_value; > + } > + > +done: > + > /* Update SE's clamp values and attach it to new clamp group */ > uc_se->value = clamp_value; > uc_se->group_id = group_id;