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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 D2811C4332D for ; Thu, 19 Mar 2020 12:06:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF9B920663 for ; Thu, 19 Mar 2020 12:06:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727099AbgCSMGb (ORCPT ); Thu, 19 Mar 2020 08:06:31 -0400 Received: from foss.arm.com ([217.140.110.172]:34076 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725767AbgCSMGb (ORCPT ); Thu, 19 Mar 2020 08:06:31 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C895D31B; Thu, 19 Mar 2020 05:06:30 -0700 (PDT) Received: from e113632-lin (unknown [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0ABC63F305; Thu, 19 Mar 2020 05:06:29 -0700 (PDT) References: <20200311181601.18314-1-valentin.schneider@arm.com> <20200311181601.18314-5-valentin.schneider@arm.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Dietmar Eggemann Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, vincent.guittot@linaro.org Subject: Re: [PATCH v2 4/9] sched/topology: Kill SD_LOAD_BALANCE In-reply-to: Date: Thu, 19 Mar 2020 12:06:07 +0000 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 19 2020, Dietmar Eggemann wrote: > On 11.03.20 19:15, Valentin Schneider wrote: >> That flag is set unconditionally in sd_init(), and no one checks for it >> anymore. Remove it. > > Why not merge 3/9 and 4/9 ? > > [...] > >> diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h >> index f341163fedc9..8de2f9744569 100644 >> --- a/include/linux/sched/topology.h >> +++ b/include/linux/sched/topology.h >> @@ -11,21 +11,20 @@ >> */ >> #ifdef CONFIG_SMP >> >> -#define SD_LOAD_BALANCE 0x0001 /* Do load balancing on this domain. */ >> -#define SD_BALANCE_NEWIDLE 0x0002 /* Balance when about to become idle */ > > [...] > >> -#define SD_OVERLAP 0x2000 /* sched_domains of this level overlap */ >> -#define SD_NUMA 0x4000 /* cross-node balancing */ >> +#define SD_BALANCE_NEWIDLE 0x0001 /* Balance when about to become idle */ > > IMHO, changing the values of the remaining SD flags will break lots of > userspace scripts. > True, and that includes some of my own scripts. That's also part of why I have this 3/9 and 4/9 split: 4/9 is the externally visible part. If deemed necessary, we could keep the definition of SD_LOAD_BALANCE but kill all of its uses. Alternatively, I was thinking that we could leverage [1] to make /proc/sys/kernel/sched_domain/cpu*/domain*/flags print e.g. comma-separated flag names rather than flag values. That way the userland scripts would no longer have to contain some {flag_value : flag_name} translation. [1]: https://lkml.kernel.org/r/20200311183320.19186-1-valentin.schneider@arm.com > [...]