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=-7.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 C4B76C433E0 for ; Fri, 31 Jul 2020 12:05:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7F39208E4 for ; Fri, 31 Jul 2020 12:05:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732940AbgGaMFF (ORCPT ); Fri, 31 Jul 2020 08:05:05 -0400 Received: from foss.arm.com ([217.140.110.172]:56156 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732669AbgGaMFE (ORCPT ); Fri, 31 Jul 2020 08:05:04 -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 DF3D91FB; Fri, 31 Jul 2020 05:05:03 -0700 (PDT) Received: from e113632-lin.cambridge.arm.com (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C538F3F71F; Fri, 31 Jul 2020 05:05:02 -0700 (PDT) From: Valentin Schneider To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, peterz@infradead.org, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, morten.rasmussen@arm.com, Quentin Perret Subject: [PATCH v4 00/10] sched: Instrument sched domain flags Date: Fri, 31 Jul 2020 12:54:52 +0100 Message-Id: <20200731115502.12954-1-valentin.schneider@arm.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I've repeatedly stared at an SD flag and asked myself "how should that be set up in the domain hierarchy anyway?". I figured that if we formalize our flags zoology a bit, we could also do some runtime assertions on them - this is what this series is all about. Patches ======= The idea is to associate the flags with metaflags that describes how they should be set in a sched domain hierarchy ("if this SD has it, all its {parents, children} have it") or how they behave wrt degeneration - details are in the comments and commit logs. The good thing is that the debugging bits go away when CONFIG_SCHED_DEBUG isn't set. The bad thing is that this replaces SD_* flags definitions with some unsavoury macros. This is mainly because I wanted to avoid having to duplicate work between declaring the flags and declaring their metaflags. o Patches 1-3 are topology cleanups / fixes o Patches 4-6 instrument SD flags and add assertions o Patches 7-10 leverage the instrumentation to factorize domain degeneration Revisions ========= v3 -> v4 -------- o Reordered the series to have fixes / cleanups first o Added SD_ASYM_CPUCAPACITY propagation (Quentin) o Made ARM revert back to the default sched topology (Dietmar) o Removed SD_SERIALIZE degeneration special case (Peter) o Made SD_NUMA and SD_SERIALIZE have SDF_NEEDS_GROUPS As discussed on v3, I thought this wasn't required, but thinking some more about it there can be cases where that changes the current behaviour. For instance, in the following wacky triangle: 0\ 30 | \ 20 | 2 | / 1/ 30 there are two unique distances thus two NUMA topology levels, however the first one for node 2 would have the same span as its child domain and thus should be degenerated. If we don't give SD_NUMA and SD_SERIALIZE SDF_NEEDS_GROUPS, this domain wouldn't be denegerated since its child *doesn't* have either SD_NUMA or SD_SERIALIZE (it's the first NUMA domain), and we'd have this weird NUMA domain lingering with a single group. v2 -> v3 -------- o Reworded comment for SD_OVERLAP (it's about the groups, not the domains) o Added more flags to the SD degeneration mask o Added generation of an SD flag mask for the degeneration functions (Peter) RFC -> v2 --------- o Rebased on top of tip/sched/core o Aligned wording of comments between flags o Rectified some flag descriptions (Morten) o Added removal of SD_SHARE_POWERDOMAIN (Morten) Valentin Schneider (10): ARM, sched/topology: Remove SD_SHARE_POWERDOMAIN ARM: Revert back to default scheduler topology. sched/topology: Propagate SD_ASYM_CPUCAPACITY upwards sched/topology: Split out SD_* flags declaration to its own file sched/topology: Define and assign sched_domain flag metadata sched/topology: Verify SD_* flags setup when sched_debug is on sched/topology: Add more flags to the SD degeneration mask sched/topology: Remove SD_SERIALIZE degeneration special case sched/topology: Introduce SD metaflag for flags needing > 1 groups sched/topology: Use prebuilt SD flag degeneration mask arch/arm/kernel/topology.c | 26 ------ include/linux/sched/sd_flags.h | 156 +++++++++++++++++++++++++++++++++ include/linux/sched/topology.h | 36 +++++--- kernel/sched/topology.c | 54 ++++++------ 4 files changed, 204 insertions(+), 68 deletions(-) create mode 100644 include/linux/sched/sd_flags.h -- 2.27.0