The following commit has been merged into the sched/core branch of tip: Commit-ID: 3a6712c7685352a5d71eaf459a4fddfc3589f018 Gitweb: https://git.kernel.org/tip/3a6712c7685352a5d71eaf459a4fddfc3589f018 Author: Valentin Schneider <valentin.schneider@xxxxxxx> AuthorDate: Mon, 17 Aug 2020 12:29:57 +01:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Wed, 19 Aug 2020 10:49:49 +02:00 sched/topology: Mark SD_PREFER_SIBLING as SDF_NEEDS_GROUPS SD_PREFER_SIBLING is currently considered in sd_parent_degenerate() but not in sd_degenerate(). It too hinges on load balancing, and thus won't have any effect when set on a domain with a single group. Add it to SD_DEGENERATE_GROUPS_MASK. Signed-off-by: Valentin Schneider <valentin.schneider@xxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Link: https://lore.kernel.org/r/20200817113003.20802-12-valentin.schneider@xxxxxxx --- include/linux/sched/sd_flags.h | 4 +++- kernel/sched/topology.c | 2 +- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/include/linux/sched/sd_flags.h b/include/linux/sched/sd_flags.h index 40ad0d5..d28fe67 100644 --- a/include/linux/sched/sd_flags.h +++ b/include/linux/sched/sd_flags.h @@ -131,8 +131,10 @@ SD_FLAG(SD_ASYM_PACKING, SDF_SHARED_CHILD) * * Set up until domains start spanning NUMA nodes. Close to being a SHARED_CHILD * flag, but cleared below domains with SD_ASYM_CPUCAPACITY. + * + * NEEDS_GROUPS: Load balancing flag. */ -SD_FLAG(SD_PREFER_SIBLING, 0) +SD_FLAG(SD_PREFER_SIBLING, SDF_NEEDS_GROUPS) /* * sched_groups of this level overlap diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c index f36ed96..c674aaa 100644 --- a/kernel/sched/topology.c +++ b/kernel/sched/topology.c @@ -184,7 +184,7 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) /* Flags needing groups don't count if only 1 group in parent */ if (parent->groups == parent->groups->next) - pflags &= ~(SD_DEGENERATE_GROUPS_MASK | SD_PREFER_SIBLING); + pflags &= ~SD_DEGENERATE_GROUPS_MASK; if (~cflags & pflags) return 0;
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