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 92611C282C0 for ; Wed, 23 Jan 2019 18:59:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 653C82184B for ; Wed, 23 Jan 2019 18:59:50 +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="I9aCRh9N" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726249AbfAWS7s (ORCPT ); Wed, 23 Jan 2019 13:59:48 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:52982 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726027AbfAWS7s (ORCPT ); Wed, 23 Jan 2019 13:59:48 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=dgfqcSanb6lp9vXdmjSxOrnt6Pt+KGuiUR8MqoSxjtE=; b=I9aCRh9NxXEkgaarWs8JkHsB2 TMXVjUSy/Hy9/cXLp1VbmmzrZe1f5hkReu9jj0zg2LBmSSyjGnk0yngC3grF4incfpJpTJyKdIGoC lqYlLWvPM6ZwYYg49Ue10/qM+HZsduT+3xFZSH5bITQ4Z9J8qoMTE8TsVhlj6OZZqJxCZTKEIA/+Y onAhUUGqPzCZZu+qp5tEiXcEOorfzECaY/xg4lEA6zaWdnef7LObxH+Y/ymDjVjO8gJ8l+LEpliAF GsNitQuAT5I8kFwQXvYa5sxbBgXfHMQ8FzIk/omNNI46UI0IlmvwxkAduLNKAGPCZJKnfgdFIYBaL Gwoxb553w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gmNkV-0000w4-0X; Wed, 23 Jan 2019 18:59:43 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 4BD1C201EC16E; Wed, 23 Jan 2019 19:59:40 +0100 (CET) Date: Wed, 23 Jan 2019 19:59:40 +0100 From: Peter Zijlstra To: Patrick Bellasi Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-api@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 v6 05/16] sched/core: uclamp: Update CPU's refcount on clamp changes Message-ID: <20190123185940.GF17749@hirez.programming.kicks-ass.net> References: <20190121153308.GL27931@hirez.programming.kicks-ass.net> <20190121154412.fak2t2iquj3aixtu@e110439-lin> <20190122093704.GM27931@hirez.programming.kicks-ass.net> <20190122104305.6vjx37muqsxm536t@e110439-lin> <20190122132817.GG13777@hirez.programming.kicks-ass.net> <20190122140115.twtx646vewm757ca@e110439-lin> <20190122145742.GQ27931@hirez.programming.kicks-ass.net> <20190122153315.dhjl67sgpu74hmqv@e110439-lin> <20190123091634.GT27931@hirez.programming.kicks-ass.net> <20190123141426.5samtr4hl6okdypu@e110439-lin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190123141426.5samtr4hl6okdypu@e110439-lin> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 23, 2019 at 02:14:26PM +0000, Patrick Bellasi wrote: > > > Consider also that the uclamp_task_update_active() added by this patch > > > not only has lower overhead but it will be use also by cgroups where > > > we want to force update all the tasks on a cgroup's clamp change. > > > > I haven't gotten that far; but I would prefer not to have two different > > 'change' paths in __sched_setscheduler(). > > Yes, I agree that two paths in __sched_setscheduler() could be > confusing. Still we have to consider that here we are adding > "not class specific" attributes. But that change thing is not class specific; the whole: rq = task_rq_lock(p, &rf); queued = task_on_rq_queued(p); running = task_current(rq, p); if (queued) dequeue_task(rq, p, queue_flags); if (running) put_prev_task(rq, p); /* @p is in it's invariant state; frob it's state */ if (queued) enqueue_task(rq, p, queue_flags); if (running) set_curr_task(rq, p); task_rq_unlock(rq, p, &rf); pattern is all over the place; it is just because C sucks that that isn't more explicitly shared (do_set_cpus_allowed(), rt_mutex_setprio(), set_user_nice(), __sched_setscheduler(), sched_setnuma(), sched_move_task()). This is _the_ pattern for changing state and is not class specific at all.