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 7E2BAC0044C for ; Wed, 7 Nov 2018 13:58:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 422DD2085B for ; Wed, 7 Nov 2018 13:58:12 +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="SxUv/afP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 422DD2085B 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 S1730660AbeKGX2k (ORCPT ); Wed, 7 Nov 2018 18:28:40 -0500 Received: from merlin.infradead.org ([205.233.59.134]:60982 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727168AbeKGX2k (ORCPT ); Wed, 7 Nov 2018 18:28:40 -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=EltP8ilXjkv36t1bw1TG5a0Czq2nBHXdy4S7Z15GOtE=; b=SxUv/afPVdYpf1ZVY+PTm0CeM RFSwfZgn0sDUHzEGnNMZaiK2fj+0vm9K1vBLZHM7zx3DLaomdkT/DRIqzc+RzbPwEdghwWmJK3ql2 vZhnlBFbHT3qxv5zxlL0JmI35lttZHhuIHs0069DLIZR2zlaue8zTi9fu7EMvKoBgSY9qwBK+onNn KBwLtEIt6/VOLhV7cpgOPshA6xpvWjs+iL24OvHr7fP/YCbdVFFu5zfqalMLeb2pZFQ240oywqmTq Vx5P3IH1EXxFQRxvsP59qTd6APaABQjB7N45c2itL+qLr6qVnKli88lEJkyef4tcft+VwDv7GoCgs vIUiUOiXQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gKOLL-00068w-Te; Wed, 07 Nov 2018 13:58:04 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id C03302029F883; Wed, 7 Nov 2018 14:58:01 +0100 (CET) Date: Wed, 7 Nov 2018 14:58:01 +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 , linux-api@vger.kernel.org Subject: Re: [PATCH v5 02/15] sched/core: make sched_setattr able to tune the current policy Message-ID: <20181107135801.GE9761@hirez.programming.kicks-ass.net> References: <20181029183311.29175-1-patrick.bellasi@arm.com> <20181029183311.29175-3-patrick.bellasi@arm.com> <20181107121126.GN9781@hirez.programming.kicks-ass.net> <20181107135039.GD14309@e110439-lin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181107135039.GD14309@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, Nov 07, 2018 at 01:50:39PM +0000, Patrick Bellasi wrote: > On 07-Nov 13:11, Peter Zijlstra wrote: > > On Mon, Oct 29, 2018 at 06:32:56PM +0000, Patrick Bellasi wrote: > > > > > @@ -50,11 +52,13 @@ > > > #define SCHED_FLAG_RESET_ON_FORK 0x01 > > > #define SCHED_FLAG_RECLAIM 0x02 > > > #define SCHED_FLAG_DL_OVERRUN 0x04 > > > -#define SCHED_FLAG_UTIL_CLAMP 0x08 > > > +#define SCHED_FLAG_TUNE_POLICY 0x08 > > > +#define SCHED_FLAG_UTIL_CLAMP 0x10 > > > > That seems to suggest you want to do this patch first, but you didn't.. > > I've kept it here just to better highlight this change, suggested by > Juri, since we was not entirely sure you are fine with it... > > If you think it's ok adding a SCHED_FLAG_TUNE_POLICY behavior to the > sched_setattr syscall, I can certainly squash into the previous patch, > which gives more context on why we need it. I'm fine with the idea I think. It's the details I worry about. Which fields in particular are not updated with this. Are flags? Also, I'm not too keen on the name; since it explicitly does not modify the policy and its related parameters, so TUNE_POLICY is actively wrong. But the thing that confused me most is how fiddled the numbers to fit this before UTIL_CLAMP. > Since we are at that, are we supposed to document some{where,how} > these API changes ? I'm pretty sure there's a manpage somewhere... SCHED_SETATTR(2) seems to exist on my machine. So that wants updates.