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 720BBC43610 for ; Tue, 20 Nov 2018 10:24:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 65E2420671 for ; Tue, 20 Nov 2018 10:24:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65E2420671 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 S1727497AbeKTUxS (ORCPT ); Tue, 20 Nov 2018 15:53:18 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:46324 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726250AbeKTUxS (ORCPT ); Tue, 20 Nov 2018 15:53:18 -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 5E10EEBD; Tue, 20 Nov 2018 02:24:54 -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 008A23F575; Tue, 20 Nov 2018 02:24:51 -0800 (PST) Subject: Re: [PATCH v3 05/10] sched/fair: Hoist idle_stamp up from idle_balance To: Steven 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: <1541767840-93588-1-git-send-email-steven.sistare@oracle.com> <1541767840-93588-6-git-send-email-steven.sistare@oracle.com> <9ad62a6f-0269-a5d9-9757-ba5419f9cc1d@arm.com> <0d8ceaff-6368-2dff-9e2c-e5928ab39bab@oracle.com> From: Valentin Schneider Message-ID: Date: Tue, 20 Nov 2018 10:24:50 +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: <0d8ceaff-6368-2dff-9e2c-e5928ab39bab@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 19/11/2018 17:31, Steven Sistare wrote: [...] >>> +#define IF_SMP(statement) statement >>> + >> >> I'm not too hot on those IF_SMP() macros. Since you're not introducing >> any other user for them, what about an inline function for rq->idle_stamp >> setting ? When it's mapped to an empty statement (!CONFIG_SMP) GCC is >> smart enough to remove the rq_clock() that would be passed to it on >> CONFIG_SMP: > > That may be true now, but I worry that rq_clock or its subroutines may gain > side effects in the future that prevent the compiler from removing it. However, > I could push rq_clock into the inline function: > > static inline void rq_idle_stamp_set(rq) { rq->idle_stamp = rq_clock(rq); } > static inline void rq_idle_stamp_clear(rq) { rq->idle_stamp = 0; } > > I like that better, do you? > That works for me, though I can't resist nitpicking on s/rq_idle_stamp_set/rq_idle_stamp_update/ > - Steve