Pull model-name into release branch

[linux-2.6-microblaze.git] / kernel / cpuset.c

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 1a649f2..4ea6f0d 100644 (file)
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -816,6 +816,10 @@ static int update_cpumask(struct cpuset *cs, char *buf)
        struct cpuset trialcs;
        int retval, cpus_unchanged;
 
+       /* top_cpuset.cpus_allowed tracks cpu_online_map; it's read-only */
+       if (cs == &top_cpuset)
+               return -EACCES;
+
        trialcs = *cs;
        retval = cpulist_parse(buf, trialcs.cpus_allowed);
        if (retval < 0)
@@ -2033,6 +2037,33 @@ out:
        return err;
 }
 
+/*
+ * The top_cpuset tracks what CPUs and Memory Nodes are online,
+ * period.  This is necessary in order to make cpusets transparent
+ * (of no affect) on systems that are actively using CPU hotplug
+ * but making no active use of cpusets.
+ *
+ * This handles CPU hotplug (cpuhp) events.  If someday Memory
+ * Nodes can be hotplugged (dynamically changing node_online_map)
+ * then we should handle that too, perhaps in a similar way.
+ */
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int cpuset_handle_cpuhp(struct notifier_block *nb,
+                               unsigned long phase, void *cpu)
+{
+       mutex_lock(&manage_mutex);
+       mutex_lock(&callback_mutex);
+
+       top_cpuset.cpus_allowed = cpu_online_map;
+
+       mutex_unlock(&callback_mutex);
+       mutex_unlock(&manage_mutex);
+
+       return 0;
+}
+#endif
+
 /**
  * cpuset_init_smp - initialize cpus_allowed
  *
@@ -2043,6 +2074,8 @@ void __init cpuset_init_smp(void)
 {
        top_cpuset.cpus_allowed = cpu_online_map;
        top_cpuset.mems_allowed = node_online_map;
+
+       hotcpu_notifier(cpuset_handle_cpuhp, 0);
 }
 
 /**
@@ -2387,7 +2420,7 @@ EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
 int cpuset_excl_nodes_overlap(const struct task_struct *p)
 {
        const struct cpuset *cs1, *cs2; /* my and p's cpuset ancestors */
-       int overlap = 0;                /* do cpusets overlap? */
+       int overlap = 1;                /* do cpusets overlap? */
 
        task_lock(current);
        if (current->flags & PF_EXITING) {