sched/topology: Align group flags when removing degenerate domain

The flags of the child of a given scheduling domain are used to initialize
the flags of its scheduling groups. When the child of a scheduling domain
is degenerated, the flags of its local scheduling group need to be updated
to align with the flags of its new child domain.

The flag SD_SHARE_CPUCAPACITY was aligned in
Commit bf2dc42 ("sched/topology: Propagate SMT flags when removing degenerate domain").
Further generalize this alignment so other flags can be used later, such as
in cluster-based task wakeup. [1]

Reported-by: Yicong Yang <[email protected]>
Suggested-by: Ricardo Neri <[email protected]>
Signed-off-by: Chen Yu <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Tim Chen <[email protected]>
Reviewed-by: Yicong Yang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: yu-chen-surf

kernel/sched/topology.c

@@ -722,8 +722,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
 
 			if (parent->parent) {
 				parent->parent->child = tmp;
-				if (tmp->flags & SD_SHARE_CPUCAPACITY)
-					parent->parent->groups->flags |= SD_SHARE_CPUCAPACITY;
+				parent->parent->groups->flags = tmp->flags;
 			}
 
 			/*