static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sds)
{
- struct sched_domain *child = env->sd->child;
struct sched_group *sg = env->sd->groups;
struct sg_lb_stats *local = &sds->local_stat;
struct sg_lb_stats tmp_sgs;
sg = sg->next;
} while (sg != env->sd->groups);
- /* Tag domain that child domain prefers tasks go to siblings first */
- sds->prefer_sibling = child && child->flags & SD_PREFER_SIBLING;
+ /*
+ * Indicate that the child domain of the busiest group prefers tasks
+ * go to a child's sibling domains first. NB the flags of a sched group
+ * are those of the child domain.
+ */
+ if (sds->busiest)
+ sds->prefer_sibling = !!(sds->busiest->flags & SD_PREFER_SIBLING);
if (env->sd->flags & SD_NUMA)
goto out_balanced;
}
- /* Try to move all excess tasks to child's sibling domain */
+ /*
+ * Try to move all excess tasks to a sibling domain of the busiest
+ * group's child domain.
+ */
if (sds.prefer_sibling && local->group_type == group_has_spare &&
busiest->sum_nr_running > local->sum_nr_running + 1)
goto force_balance;