From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1947079AbcHRK4u (ORCPT ); Thu, 18 Aug 2016 06:56:50 -0400 Received: from terminus.zytor.com ([198.137.202.10]:58144 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751505AbcHRK4r (ORCPT ); Thu, 18 Aug 2016 06:56:47 -0400 Date: Thu, 18 Aug 2016 03:56:06 -0700 From: tip-bot for Peter Zijlstra Message-ID: Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, peterz@infradead.org, efault@gmx.de, hpa@zytor.com, morten.rasmussen@arm.com Reply-To: hpa@zytor.com, morten.rasmussen@arm.com, efault@gmx.de, peterz@infradead.org, torvalds@linux-foundation.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, mingo@kernel.org In-Reply-To: <20160815105459.GS6879@twins.programming.kicks-ass.net> References: <20160815105459.GS6879@twins.programming.kicks-ass.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/core: Clarify SD_flags comment Git-Commit-ID: 94f438c84e850570f28dd36588a0d7f73b991e44 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 94f438c84e850570f28dd36588a0d7f73b991e44 Gitweb: http://git.kernel.org/tip/94f438c84e850570f28dd36588a0d7f73b991e44 Author: Peter Zijlstra AuthorDate: Mon, 15 Aug 2016 12:54:59 +0200 Committer: Ingo Molnar CommitDate: Thu, 18 Aug 2016 11:26:52 +0200 sched/core: Clarify SD_flags comment The SD_flags comment is very terse and doesn't explain why PACKING is odd. IIRC the distinction is that the 'normal' ones only describe topology, while the ASYM_PACKING one also prescribes behaviour. It is odd in the way that it doesn't only describe things. Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Morten Rasmussen Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dietmar.eggemann@arm.com Cc: freedom.tan@mediatek.com Cc: keita.kobayashi.ym@renesas.com Cc: mgalbraith@suse.de Cc: sgurrappadi@nvidia.com Cc: vincent.guittot@linaro.org Cc: yuyang.du@intel.com Link: http://lkml.kernel.org/r/20160815105459.GS6879@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3b6b23c..54fff81 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6355,13 +6355,19 @@ static int sched_domains_curr_level; /* * SD_flags allowed in topology descriptions. * - * SD_SHARE_CPUCAPACITY - describes SMT topologies - * SD_SHARE_PKG_RESOURCES - describes shared caches - * SD_NUMA - describes NUMA topologies - * SD_SHARE_POWERDOMAIN - describes shared power domain + * These flags are purely descriptive of the topology and do not prescribe + * behaviour. Behaviour is artificial and mapped in the below sd_init() + * function: * - * Odd one out: - * SD_ASYM_PACKING - describes SMT quirks + * SD_SHARE_CPUCAPACITY - describes SMT topologies + * SD_SHARE_PKG_RESOURCES - describes shared caches + * SD_NUMA - describes NUMA topologies + * SD_SHARE_POWERDOMAIN - describes shared power domain + * + * Odd one out, which beside describing the topology has a quirk also + * prescribes the desired behaviour that goes along with it: + * + * SD_ASYM_PACKING - describes SMT quirks */ #define TOPOLOGY_SD_FLAGS \ (SD_SHARE_CPUCAPACITY | \