cpu hotplug, sched: Introduce cpu_active_map and redo sched domain managment (take 2)

[safe/jmp/linux-2.6] / kernel / cpu.c

diff --git a/kernel/cpu.c b/kernel/cpu.c
index c77bc3a..a1ac7ea 100644 (file)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -15,6 +15,28 @@
 #include <linux/stop_machine.h>
 #include <linux/mutex.h>
 
+/*
+ * Represents all cpu's present in the system
+ * In systems capable of hotplug, this map could dynamically grow
+ * as new cpu's are detected in the system via any platform specific
+ * method, such as ACPI for e.g.
+ */
+cpumask_t cpu_present_map __read_mostly;
+EXPORT_SYMBOL(cpu_present_map);
+
+#ifndef CONFIG_SMP
+
+/*
+ * Represents all cpu's that are currently online.
+ */
+cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL;
+EXPORT_SYMBOL(cpu_online_map);
+
+cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;
+EXPORT_SYMBOL(cpu_possible_map);
+
+#else /* CONFIG_SMP */
+
 /* Serializes the updates to cpu_online_map, cpu_present_map */
 static DEFINE_MUTEX(cpu_add_remove_lock);
 
@@ -42,6 +64,8 @@ void __init cpu_hotplug_init(void)
        cpu_hotplug.refcount = 0;
 }
 
+cpumask_t cpu_active_map;
+
 #ifdef CONFIG_HOTPLUG_CPU
 
 void get_online_cpus(void)
@@ -269,14 +293,24 @@ int __ref cpu_down(unsigned int cpu)
        int err = 0;
 
        cpu_maps_update_begin();
-       if (cpu_hotplug_disabled)
+
+       if (cpu_hotplug_disabled) {
                err = -EBUSY;
-       else
-               err = _cpu_down(cpu, 0);
+               goto out;
+       }
+
+       cpu_clear(cpu, cpu_active_map);
+
+       err = _cpu_down(cpu, 0);
 
+       if (cpu_online(cpu))
+               cpu_set(cpu, cpu_active_map);
+
+out:
        cpu_maps_update_done();
        return err;
 }
+EXPORT_SYMBOL(cpu_down);
 #endif /*CONFIG_HOTPLUG_CPU*/
 
 /* Requires cpu_add_remove_lock to be held */
@@ -332,11 +366,18 @@ int __cpuinit cpu_up(unsigned int cpu)
        }
 
        cpu_maps_update_begin();
-       if (cpu_hotplug_disabled)
+
+       if (cpu_hotplug_disabled) {
                err = -EBUSY;
-       else
-               err = _cpu_up(cpu, 0);
+               goto out;
+       }
+
+       err = _cpu_up(cpu, 0);
 
+       if (cpu_online(cpu))
+               cpu_set(cpu, cpu_active_map);
+
+out:
        cpu_maps_update_done();
        return err;
 }
@@ -403,3 +444,5 @@ out:
        cpu_maps_update_done();
 }
 #endif /* CONFIG_PM_SLEEP_SMP */
+
+#endif /* CONFIG_SMP */