From 94f438c84e850570f28dd36588a0d7f73b991e44 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 15 Aug 2016 12:54:59 +0200 Subject: [PATCH] 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 3b6b23c57418..54fff8109922 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 | \ -- 2.39.2