2 files changed, 88 insertions, 46 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index edb2c69a8873..98c109e4f43d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -539,6 +539,8 @@ struct sched_domain {
 #endif
 };
 
+extern void partition_sched_domains(cpumask_t *partition1,
+                                    cpumask_t *partition2);
 #ifdef ARCH_HAS_SCHED_DOMAIN
 /* Useful helpers that arch setup code may use. Defined in kernel/sched.c */
 extern cpumask_t cpu_isolated_map;
diff --git a/kernel/sched.c b/kernel/sched.c
index d3d81b82e378..dee96b22635e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -262,7 +262,7 @@ static DEFINE_PER_CPU(struct runqueue, runqueues);
 
 /*
  * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
- * See update_sched_domains: synchronize_kernel for details.
+ * See detach_destroy_domains: synchronize_sched for details.
  *
  * The domain tree of any CPU may only be accessed from within
  * preempt-disabled sections.
@@ -4624,7 +4624,7 @@ int __init migration_init(void)
 #endif
 
 #ifdef CONFIG_SMP
-#define SCHED_DOMAIN_DEBUG
+#undef SCHED_DOMAIN_DEBUG
 #ifdef SCHED_DOMAIN_DEBUG
 static void sched_domain_debug(struct sched_domain *sd, int cpu)
 {
@@ -4717,7 +4717,7 @@ static void sched_domain_debug(struct sched_domain *sd, int cpu)
 #define sched_domain_debug(sd, cpu) {}
 #endif
 
-static int __devinit sd_degenerate(struct sched_domain *sd)
+static int sd_degenerate(struct sched_domain *sd)
 {
         if (cpus_weight(sd->span) == 1)
                 return 1;
@@ -4740,7 +4740,7 @@ static int __devinit sd_degenerate(struct sched_domain *sd)
         return 1;
 }
 
-static int __devinit sd_parent_degenerate(struct sched_domain *sd,
+static int sd_parent_degenerate(struct sched_domain *sd,
                                                 struct sched_domain *parent)
 {
         unsigned long cflags = sd->flags, pflags = parent->flags;
@@ -4772,7 +4772,7 @@ static int __devinit sd_parent_degenerate(struct sched_domain *sd,
  * Attach the domain 'sd' to 'cpu' as its base domain.  Callers must
  * hold the hotplug lock.
  */
-void __devinit cpu_attach_domain(struct sched_domain *sd, int cpu)
+void cpu_attach_domain(struct sched_domain *sd, int cpu)
 {
         runqueue_t *rq = cpu_rq(cpu);
         struct sched_domain *tmp;
@@ -4823,7 +4823,7 @@ __setup ("isolcpus=", isolated_cpu_setup);
  * covered by the given span, and will set each group's ->cpumask correctly,
  * and ->cpu_power to 0.
  */
-void __devinit init_sched_build_groups(struct sched_group groups[],
+void init_sched_build_groups(struct sched_group groups[],
                         cpumask_t span, int (*group_fn)(int cpu))
 {
         struct sched_group *first = NULL, *last = NULL;
@@ -4859,13 +4859,14 @@ void __devinit init_sched_build_groups(struct sched_group groups[],
 
 
 #ifdef ARCH_HAS_SCHED_DOMAIN
-extern void __devinit arch_init_sched_domains(void);
-extern void __devinit arch_destroy_sched_domains(void);
+extern void build_sched_domains(const cpumask_t *cpu_map);
+extern void arch_init_sched_domains(const cpumask_t *cpu_map);
+extern void arch_destroy_sched_domains(const cpumask_t *cpu_map);
 #else
 #ifdef CONFIG_SCHED_SMT
 static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
 static struct sched_group sched_group_cpus[NR_CPUS];
-static int __devinit cpu_to_cpu_group(int cpu)
+static int cpu_to_cpu_group(int cpu)
 {
         return cpu;
 }
@@ -4873,7 +4874,7 @@ static int __devinit cpu_to_cpu_group(int cpu)
 
 static DEFINE_PER_CPU(struct sched_domain, phys_domains);
 static struct sched_group sched_group_phys[NR_CPUS];
-static int __devinit cpu_to_phys_group(int cpu)
+static int cpu_to_phys_group(int cpu)
 {
 #ifdef CONFIG_SCHED_SMT
         return first_cpu(cpu_sibling_map[cpu]);
@@ -4886,7 +4887,7 @@ static int __devinit cpu_to_phys_group(int cpu)
 
 static DEFINE_PER_CPU(struct sched_domain, node_domains);
 static struct sched_group sched_group_nodes[MAX_NUMNODES];
-static int __devinit cpu_to_node_group(int cpu)
+static int cpu_to_node_group(int cpu)
 {
         return cpu_to_node(cpu);
 }
@@ -4917,39 +4918,28 @@ static void check_sibling_maps(void)
 #endif
 
 /*
- * Set up scheduler domains and groups.  Callers must hold the hotplug lock.
+ * Build sched domains for a given set of cpus and attach the sched domains
+ * to the individual cpus
  */
-static void __devinit arch_init_sched_domains(void)
+static void build_sched_domains(const cpumask_t *cpu_map)
 {
         int i;
-        cpumask_t cpu_default_map;
-
-#if defined(CONFIG_SCHED_SMT) && defined(CONFIG_NUMA)
-        check_sibling_maps();
-#endif
-        /*
-         * Setup mask for cpus without special case scheduling requirements.
-         * For now this just excludes isolated cpus, but could be used to
-         * exclude other special cases in the future.
-         */
-        cpus_complement(cpu_default_map, cpu_isolated_map);
-        cpus_and(cpu_default_map, cpu_default_map, cpu_online_map);
 
         /*
-         * Set up domains. Isolated domains just stay on the NULL domain.
+         * Set up domains for cpus specified by the cpu_map.
          */
-        for_each_cpu_mask(i, cpu_default_map) {
+        for_each_cpu_mask(i, *cpu_map) {
                 int group;
                 struct sched_domain *sd = NULL, *p;
                 cpumask_t nodemask = node_to_cpumask(cpu_to_node(i));
 
-                cpus_and(nodemask, nodemask, cpu_default_map);
+                cpus_and(nodemask, nodemask, *cpu_map);
 
 #ifdef CONFIG_NUMA
                 sd = &per_cpu(node_domains, i);
                 group = cpu_to_node_group(i);
                 *sd = SD_NODE_INIT;
-                sd->span = cpu_default_map;
+                sd->span = *cpu_map;
                 sd->groups = &sched_group_nodes[group];
 #endif
 
@@ -4967,7 +4957,7 @@ static void __devinit arch_init_sched_domains(void)
                 group = cpu_to_cpu_group(i);
                 *sd = SD_SIBLING_INIT;
                 sd->span = cpu_sibling_map[i];
-                cpus_and(sd->span, sd->span, cpu_default_map);
+                cpus_and(sd->span, sd->span, *cpu_map);
                 sd->parent = p;
                 sd->groups = &sched_group_cpus[group];
 #endif
@@ -4977,7 +4967,7 @@ static void __devinit arch_init_sched_domains(void)
         /* Set up CPU (sibling) groups */
         for_each_online_cpu(i) {
                 cpumask_t this_sibling_map = cpu_sibling_map[i];
-                cpus_and(this_sibling_map, this_sibling_map, cpu_default_map);
+                cpus_and(this_sibling_map, this_sibling_map, *cpu_map);
                 if (i != first_cpu(this_sibling_map))
                         continue;
 
@@ -4990,7 +4980,7 @@ static void __devinit arch_init_sched_domains(void)
         for (i = 0; i < MAX_NUMNODES; i++) {
                 cpumask_t nodemask = node_to_cpumask(i);
 
-                cpus_and(nodemask, nodemask, cpu_default_map);
+                cpus_and(nodemask, nodemask, *cpu_map);
                 if (cpus_empty(nodemask))
                         continue;
 
@@ -5000,12 +4990,12 @@ static void __devinit arch_init_sched_domains(void)
 
 #ifdef CONFIG_NUMA
         /* Set up node groups */
-        init_sched_build_groups(sched_group_nodes, cpu_default_map,
+        init_sched_build_groups(sched_group_nodes, *cpu_map,
                                         &cpu_to_node_group);
 #endif
 
         /* Calculate CPU power for physical packages and nodes */
-        for_each_cpu_mask(i, cpu_default_map) {
+        for_each_cpu_mask(i, *cpu_map) {
                 int power;
                 struct sched_domain *sd;
 #ifdef CONFIG_SCHED_SMT
@@ -5029,7 +5019,7 @@ static void __devinit arch_init_sched_domains(void)
         }
 
         /* Attach the domains */
-        for_each_online_cpu(i) {
+        for_each_cpu_mask(i, *cpu_map) {
                 struct sched_domain *sd;
 #ifdef CONFIG_SCHED_SMT
                 sd = &per_cpu(cpu_domains, i);
@@ -5039,16 +5029,71 @@ static void __devinit arch_init_sched_domains(void)
                 cpu_attach_domain(sd, i);
         }
 }
+/*
+ * Set up scheduler domains and groups.  Callers must hold the hotplug lock.
+ */
+static void arch_init_sched_domains(cpumask_t *cpu_map)
+{
+        cpumask_t cpu_default_map;
 
-#ifdef CONFIG_HOTPLUG_CPU
-static void __devinit arch_destroy_sched_domains(void)
+#if defined(CONFIG_SCHED_SMT) && defined(CONFIG_NUMA)
+        check_sibling_maps();
+#endif
+        /*
+         * Setup mask for cpus without special case scheduling requirements.
+         * For now this just excludes isolated cpus, but could be used to
+         * exclude other special cases in the future.
+         */
+        cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map);
+
+        build_sched_domains(&cpu_default_map);
+}
+
+static void arch_destroy_sched_domains(const cpumask_t *cpu_map)
 {
         /* Do nothing: everything is statically allocated. */
 }
-#endif
 
 #endif /* ARCH_HAS_SCHED_DOMAIN */
 
+/*
+ * Detach sched domains from a group of cpus specified in cpu_map
+ * These cpus will now be attached to the NULL domain
+ */
+static inline void detach_destroy_domains(const cpumask_t *cpu_map)
+{
+        int i;
+
+        for_each_cpu_mask(i, *cpu_map)
+                cpu_attach_domain(NULL, i);
+        synchronize_sched();
+        arch_destroy_sched_domains(cpu_map);
+}
+
+/*
+ * Partition sched domains as specified by the cpumasks below.
+ * This attaches all cpus from the cpumasks to the NULL domain,
+ * waits for a RCU quiescent period, recalculates sched
+ * domain information and then attaches them back to the
+ * correct sched domains
+ * Call with hotplug lock held
+ */
+void partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2)
+{
+        cpumask_t change_map;
+
+        cpus_and(*partition1, *partition1, cpu_online_map);
+        cpus_and(*partition2, *partition2, cpu_online_map);
+        cpus_or(change_map, *partition1, *partition2);
+
+        /* Detach sched domains from all of the affected cpus */
+        detach_destroy_domains(&change_map);
+        if (!cpus_empty(*partition1))
+                build_sched_domains(partition1);
+        if (!cpus_empty(*partition2))
+                build_sched_domains(partition2);
+}
+
 #ifdef CONFIG_HOTPLUG_CPU
 /*
  * Force a reinitialization of the sched domains hierarchy.  The domains
@@ -5059,15 +5104,10 @@ static void __devinit arch_destroy_sched_domains(void)
 static int update_sched_domains(struct notifier_block *nfb,
                                 unsigned long action, void *hcpu)
 {
-        int i;
-
         switch (action) {
         case CPU_UP_PREPARE:
         case CPU_DOWN_PREPARE:
-                for_each_online_cpu(i)
-                        cpu_attach_domain(NULL, i);
-                synchronize_kernel();
-                arch_destroy_sched_domains();
+                detach_destroy_domains(&cpu_online_map);
                 return NOTIFY_OK;
 
         case CPU_UP_CANCELED:
@@ -5083,7 +5123,7 @@ static int update_sched_domains(struct notifier_block *nfb,
         }
 
         /* The hotplug lock is already held by cpu_up/cpu_down */
-        arch_init_sched_domains();
+        arch_init_sched_domains(&cpu_online_map);
 
         return NOTIFY_OK;
 }
@@ -5092,7 +5132,7 @@ static int update_sched_domains(struct notifier_block *nfb,
 void __init sched_init_smp(void)
 {
         lock_cpu_hotplug();
-        arch_init_sched_domains();
+        arch_init_sched_domains(&cpu_online_map);
         unlock_cpu_hotplug();
         /* XXX: Theoretical race here - CPU may be hotplugged now */
         hotcpu_notifier(update_sched_domains, 0);