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From: tip-bot for Peter Zijlstra <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
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
Subject: [tip:sched/core] sched/core: Clarify SD_flags comment
Date: Thu, 18 Aug 2016 03:56:06 -0700	[thread overview]
Message-ID: <tip-94f438c84e850570f28dd36588a0d7f73b991e44@git.kernel.org> (raw)
In-Reply-To: <20160815105459.GS6879@twins.programming.kicks-ass.net>

Commit-ID:  94f438c84e850570f28dd36588a0d7f73b991e44
Gitweb:     http://git.kernel.org/tip/94f438c84e850570f28dd36588a0d7f73b991e44
Author:     Peter Zijlstra <peterz@infradead.org>
AuthorDate: Mon, 15 Aug 2016 12:54:59 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
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) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
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 <mingo@kernel.org>
---
 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 |		\

  parent reply	other threads:[~2016-08-18 10:56 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-25 13:34 [PATCH v3 00/13] sched: Clean-ups and asymmetric cpu capacity support Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 01/13] sched: Fix power to capacity renaming in comment Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 02/13] sched/fair: Consistent use of prev_cpu in wakeup path Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 03/13] sched/fair: Optimize find_idlest_cpu() when there is no choice Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 04/13] sched/core: Remove unnecessary null-pointer check Morten Rasmussen
2016-08-18 10:56   ` [tip:sched/core] sched/core: Remove unnecessary NULL-pointer check tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 05/13] sched: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag Morten Rasmussen
2016-08-15 10:54   ` Peter Zijlstra
2016-08-15 11:43     ` Morten Rasmussen
2016-08-18 10:56     ` tip-bot for Peter Zijlstra [this message]
2016-08-17  8:42   ` Wanpeng Li
2016-08-17  9:23     ` Morten Rasmussen
2016-08-17  9:26       ` Wanpeng Li
2016-08-18 10:56   ` [tip:sched/core] sched/core: " tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 06/13] sched/core: Pass child domain into sd_init Morten Rasmussen
2016-08-18 10:57   ` [tip:sched/core] sched/core: Pass child domain into sd_init() tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 07/13] sched: Enable SD_BALANCE_WAKE for asymmetric capacity systems Morten Rasmussen
2016-08-18 10:57   ` [tip:sched/core] sched/core: " tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 08/13] sched: Store maximum per-cpu capacity in root domain Morten Rasmussen
2016-08-01 18:53   ` Dietmar Eggemann
2016-08-16 12:24     ` Vincent Guittot
2016-08-18 10:58     ` [tip:sched/core] sched/core: Store maximum per-CPU " tip-bot for Dietmar Eggemann
2016-07-25 13:34 ` [PATCH v3 09/13] sched/fair: Let asymmetric cpu configurations balance at wake-up Morten Rasmussen
2016-08-15 13:39   ` Peter Zijlstra
2016-08-15 15:01     ` Morten Rasmussen
2016-08-15 15:10       ` Peter Zijlstra
2016-08-15 15:30         ` Morten Rasmussen
2016-08-18 10:58   ` [tip:sched/core] sched/fair: Let asymmetric CPU " tip-bot for Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 10/13] sched/fair: Compute task/cpu utilization at wake-up more correctly Morten Rasmussen
2016-08-15 14:23   ` Peter Zijlstra
2016-08-15 15:42     ` Morten Rasmussen
2016-08-18  8:40       ` Morten Rasmussen
2016-08-18 10:24         ` Morten Rasmussen
2016-08-18 11:46           ` Wanpeng Li
2016-08-18 13:45             ` Morten Rasmussen
2016-08-19  1:43               ` Wanpeng Li
2016-08-19 14:03                 ` Morten Rasmussen
2016-08-22  1:48                   ` Wanpeng Li
2016-08-22 11:29                     ` Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 11/13] sched/fair: Consider spare capacity in find_idlest_group() Morten Rasmussen
2016-08-16 13:57   ` Vincent Guittot
2016-08-18 11:16     ` Morten Rasmussen
2016-08-18 12:28       ` Peter Zijlstra
2016-07-25 13:34 ` [PATCH v3 12/13] sched: Add per-cpu min capacity to sched_group_capacity Morten Rasmussen
2016-07-25 13:34 ` [PATCH v3 13/13] sched/fair: Avoid pulling tasks from non-overloaded higher capacity groups Morten Rasmussen

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