8 files changed, 40 insertions, 10 deletions

diff --git a/include/asm-i386/topology.h b/include/asm-i386/topology.h
index 6adbd9b1ae88..978d09596130 100644
--- a/include/asm-i386/topology.h
+++ b/include/asm-i386/topology.h
@@ -74,6 +74,7 @@ static inline int node_to_first_cpu(int node)
 #define SD_NODE_INIT (struct sched_domain) {            \
         .span                   = CPU_MASK_NONE,        \
         .parent                 = NULL,                 \
+        .child                  = NULL,                 \
         .groups                 = NULL,                 \
         .min_interval           = 8,                    \
         .max_interval           = 32,                   \
diff --git a/include/asm-ia64/topology.h b/include/asm-ia64/topology.h
index 937c21257523..a6e38565ab4c 100644
--- a/include/asm-ia64/topology.h
+++ b/include/asm-ia64/topology.h
@@ -59,6 +59,7 @@ void build_cpu_to_node_map(void);
 #define SD_CPU_INIT (struct sched_domain) {             \
         .span                   = CPU_MASK_NONE,        \
         .parent                 = NULL,                 \
+        .child                  = NULL,                 \
         .groups                 = NULL,                 \
         .min_interval           = 1,                    \
         .max_interval           = 4,                    \
@@ -84,6 +85,7 @@ void build_cpu_to_node_map(void);
 #define SD_NODE_INIT (struct sched_domain) {            \
         .span                   = CPU_MASK_NONE,        \
         .parent                 = NULL,                 \
+        .child                  = NULL,                 \
         .groups                 = NULL,                 \
         .min_interval           = 8,                    \
         .max_interval           = 8*(min(num_online_cpus(), 32)), \
diff --git a/include/asm-mips/mach-ip27/topology.h b/include/asm-mips/mach-ip27/topology.h
index 59d26b52ba32..a13b715fd9ca 100644
--- a/include/asm-mips/mach-ip27/topology.h
+++ b/include/asm-mips/mach-ip27/topology.h
@@ -22,6 +22,7 @@ extern unsigned char __node_distances[MAX_COMPACT_NODES][MAX_COMPACT_NODES];
 #define SD_NODE_INIT (struct sched_domain) {            \
         .span                   = CPU_MASK_NONE,        \
         .parent                 = NULL,                 \
+        .child                  = NULL,                 \
         .groups                 = NULL,                 \
         .min_interval           = 8,                    \
         .max_interval           = 32,                   \
diff --git a/include/asm-powerpc/topology.h b/include/asm-powerpc/topology.h
index bbc3844b086f..8f7ee16781a4 100644
--- a/include/asm-powerpc/topology.h
+++ b/include/asm-powerpc/topology.h
@@ -43,6 +43,7 @@ extern int pcibus_to_node(struct pci_bus *bus);
 #define SD_NODE_INIT (struct sched_domain) {            \
         .span                   = CPU_MASK_NONE,        \
         .parent                 = NULL,                 \
+        .child                  = NULL,                 \
         .groups                 = NULL,                 \
         .min_interval           = 8,                    \
         .max_interval           = 32,                   \
diff --git a/include/asm-x86_64/topology.h b/include/asm-x86_64/topology.h
index 6e7a2e976b04..5c8f49280dbc 100644
--- a/include/asm-x86_64/topology.h
+++ b/include/asm-x86_64/topology.h
@@ -31,6 +31,7 @@ extern int __node_distance(int, int);
 #define SD_NODE_INIT (struct sched_domain) {            \
         .span                   = CPU_MASK_NONE,        \
         .parent                 = NULL,                 \
+        .child                  = NULL,                 \
         .groups                 = NULL,                 \
         .min_interval           = 8,                    \
         .max_interval           = 32,                   \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 38530232d92f..8e26c9069f15 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -644,6 +644,7 @@ struct sched_group {
 struct sched_domain {
         /* These fields must be setup */
         struct sched_domain *parent;    /* top domain must be null terminated */
+        struct sched_domain *child;     /* bottom domain must be null terminated */
         struct sched_group *groups;     /* the balancing groups of the domain */
         cpumask_t span;                 /* span of all CPUs in this domain */
         unsigned long min_interval;     /* Minimum balance interval ms */
diff --git a/include/linux/topology.h b/include/linux/topology.h
index ec1eca85290a..486bec23f986 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -89,6 +89,7 @@
 #define SD_SIBLING_INIT (struct sched_domain) {         \
         .span                   = CPU_MASK_NONE,        \
         .parent                 = NULL,                 \
+        .child                  = NULL,                 \
         .groups                 = NULL,                 \
         .min_interval           = 1,                    \
         .max_interval           = 2,                    \
@@ -119,6 +120,7 @@
 #define SD_CPU_INIT (struct sched_domain) {             \
         .span                   = CPU_MASK_NONE,        \
         .parent                 = NULL,                 \
+        .child                  = NULL,                 \
         .groups                 = NULL,                 \
         .min_interval           = 1,                    \
         .max_interval           = 4,                    \
@@ -146,6 +148,7 @@
 #define SD_ALLNODES_INIT (struct sched_domain) {        \
         .span                   = CPU_MASK_NONE,        \
         .parent                 = NULL,                 \
+        .child                  = NULL,                 \
         .groups                 = NULL,                 \
         .min_interval           = 64,                   \
         .max_interval           = 64*num_online_cpus(), \
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
         }