[PATCH] sched: introduce child field in sched_domain

Introduce the child field in sched_domain struct and use it in
sched_balance_self().

We will also use this field in cleaning up the sched group cpu_power
setup(done in a different patch) code.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 30 insertions, 10 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 6d7bf55ec33d..0feeacb91497 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1286,21 +1286,29 @@ static int sched_balance_self(int cpu, int flag)
         while (sd) {
                 cpumask_t span;
                 struct sched_group *group;
-                int new_cpu;
-                int weight;
+                int new_cpu, weight;
+
+                if (!(sd->flags & flag)) {
+                        sd = sd->child;
+                        continue;
+                }
 
                 span = sd->span;
                 group = find_idlest_group(sd, t, cpu);
-                if (!group)
-                        goto nextlevel;
+                if (!group) {
+                        sd = sd->child;
+                        continue;
+                }
 
                 new_cpu = find_idlest_cpu(group, t, cpu);
-                if (new_cpu == -1 || new_cpu == cpu)
-                        goto nextlevel;
+                if (new_cpu == -1 || new_cpu == cpu) {
+                        /* Now try balancing at a lower domain level of cpu */
+                        sd = sd->child;
+                        continue;
+                }
 
-                /* Now try balancing at a lower domain level */
+                /* Now try balancing at a lower domain level of new_cpu */
                 cpu = new_cpu;
-nextlevel:
                 sd = NULL;
                 weight = cpus_weight(span);
                 for_each_domain(cpu, tmp) {
@@ -5448,12 +5456,18 @@ static void cpu_attach_domain(struct sched_domain *sd, int cpu)
                 struct sched_domain *parent = tmp->parent;
                 if (!parent)
                         break;
-                if (sd_parent_degenerate(tmp, parent))
+                if (sd_parent_degenerate(tmp, parent)) {
                         tmp->parent = parent->parent;
+                        if (parent->parent)
+                                parent->parent->child = tmp;
+                }
         }
 
-        if (sd && sd_degenerate(sd))
+        if (sd && sd_degenerate(sd)) {
                 sd = sd->parent;
+                if (sd)
+                        sd->child = NULL;
+        }
 
         sched_domain_debug(sd, cpu);
 
@@ -6288,6 +6302,8 @@ static int build_sched_domains(const cpumask_t *cpu_map)
                 *sd = SD_NODE_INIT;
                 sd->span = sched_domain_node_span(cpu_to_node(i));
                 sd->parent = p;
+                if (p)
+                        p->child = sd;
                 cpus_and(sd->span, sd->span, *cpu_map);
 #endif
 
@@ -6297,6 +6313,8 @@ static int build_sched_domains(const cpumask_t *cpu_map)
                 *sd = SD_CPU_INIT;
                 sd->span = nodemask;
                 sd->parent = p;
+                if (p)
+                        p->child = sd;
                 sd->groups = &sched_group_phys[group];
 
 #ifdef CONFIG_SCHED_MC
@@ -6307,6 +6325,7 @@ static int build_sched_domains(const cpumask_t *cpu_map)
                 sd->span = cpu_coregroup_map(i);
                 cpus_and(sd->span, sd->span, *cpu_map);
                 sd->parent = p;
+                p->child = sd;
                 sd->groups = &sched_group_core[group];
 #endif
 
@@ -6318,6 +6337,7 @@ static int build_sched_domains(const cpumask_t *cpu_map)
                 sd->span = cpu_sibling_map[i];
                 cpus_and(sd->span, sd->span, *cpu_map);
                 sd->parent = p;
+                p->child = sd;
                 sd->groups = &sched_group_cpus[group];
 #endif
         }