[RFC][PATCH 08/14] sched: Simplify sched_groups_power initialization

[Peter Zijlstra]

Again, instead of relying on knowing the possible domains and their
order, simply rely on the sched_domain tree and whatever domains are
present in there to initialize the sched_group cpu_power.

Note: we need to iterate the CPU mask backwards because of the
cpumask_first() condition for iterating up the tree. By iterating the
mask backwards we ensure all groups of a domain are set-up before
starting on the parent groups that rely on its children to be
completely done.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
LKML-Reference: <new-submission>
---
 kernel/sched.c |   39 +++++----------------------------------
 1 file changed, 5 insertions(+), 34 deletions(-)

Index: linux-2.6/kernel/sched.c
===================================================================
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -7310,43 +7310,14 @@ static int __build_sched_domains(const s
 	}
 
 	/* Calculate CPU power for physical packages and nodes */
-#ifdef CONFIG_SCHED_SMT
-	for_each_cpu(i, cpu_map) {
-		sd = &per_cpu(cpu_domains, i).sd;
-		init_sched_groups_power(i, sd);
-	}
-#endif
-#ifdef CONFIG_SCHED_MC
-	for_each_cpu(i, cpu_map) {
-		sd = &per_cpu(core_domains, i).sd;
-		init_sched_groups_power(i, sd);
-	}
-#endif
-#ifdef CONFIG_SCHED_BOOK
-	for_each_cpu(i, cpu_map) {
-		sd = &per_cpu(book_domains, i).sd;
-		init_sched_groups_power(i, sd);
-	}
-#endif
-
-	for_each_cpu(i, cpu_map) {
-		sd = &per_cpu(phys_domains, i).sd;
-		init_sched_groups_power(i, sd);
-	}
-
-#ifdef CONFIG_NUMA
-	for_each_cpu(i, cpu_map) {
-		sd = &per_cpu(node_domains, i).sd;
-		init_sched_groups_power(i, sd);
-	}
+	for (i = nr_cpumask_bits-1; i >= 0; i--) {
+		if (!cpumask_test_cpu(i, cpu_map))
+			continue;
 
-	if (d.sd_allnodes) {
-		for_each_cpu(i, cpu_map) {
-			sd = &per_cpu(allnodes_domains, i).sd;
+		sd = *per_cpu_ptr(d.sd, i);
+		for (; sd; sd = sd->parent)
 			init_sched_groups_power(i, sd);
-		}
 	}
-#endif
 
 	/* Attach the domains */
 	for_each_cpu(i, cpu_map) {


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