@@ -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
@@ -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;
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@arm.com> --- include/linux/sched/sd_flags.h | 4 +++- kernel/sched/topology.c | 2 +- 2 files changed, 4 insertions(+), 2 deletions(-)