1 files changed, 28 insertions, 87 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 027a6f65f2ad..12331120767c 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -265,17 +265,6 @@ static DEFINE_MUTEX(cpuset_mutex);
 static DEFINE_MUTEX(callback_mutex);
 
 /*
- * cpuset_buffer_lock protects both the cpuset_name and cpuset_nodelist
- * buffers.  They are statically allocated to prevent using excess stack
- * when calling cpuset_print_task_mems_allowed().
- */
-#define CPUSET_NAME_LEN         (128)
-#define CPUSET_NODELIST_LEN     (256)
-static char cpuset_name[CPUSET_NAME_LEN];
-static char cpuset_nodelist[CPUSET_NODELIST_LEN];
-static DEFINE_SPINLOCK(cpuset_buffer_lock);
-
-/*
  * CPU / memory hotplug is handled asynchronously.
  */
 static struct workqueue_struct *cpuset_propagate_hotplug_wq;
@@ -780,25 +769,26 @@ static void rebuild_sched_domains_locked(void)
         lockdep_assert_held(&cpuset_mutex);
         get_online_cpus();
 
+        /*
+         * We have raced with CPU hotplug. Don't do anything to avoid
+         * passing doms with offlined cpu to partition_sched_domains().
+         * Anyways, hotplug work item will rebuild sched domains.
+         */
+        if (!cpumask_equal(top_cpuset.cpus_allowed, cpu_active_mask))
+                goto out;
+
         /* Generate domain masks and attrs */
         ndoms = generate_sched_domains(&doms, &attr);
 
         /* Have scheduler rebuild the domains */
         partition_sched_domains(ndoms, doms, attr);
-
+out:
         put_online_cpus();
 }
 #else /* !CONFIG_SMP */
 static void rebuild_sched_domains_locked(void)
 {
 }
-
-static int generate_sched_domains(cpumask_var_t **domains,
-                        struct sched_domain_attr **attributes)
-{
-        *domains = NULL;
-        return 1;
-}
 #endif /* CONFIG_SMP */
 
 void rebuild_sched_domains(void)
@@ -2005,50 +1995,6 @@ int __init cpuset_init(void)
         return 0;
 }
 
-/**
- * cpuset_do_move_task - move a given task to another cpuset
- * @tsk: pointer to task_struct the task to move
- * @scan: struct cgroup_scanner contained in its struct cpuset_hotplug_scanner
- *
- * Called by cgroup_scan_tasks() for each task in a cgroup.
- * Return nonzero to stop the walk through the tasks.
- */
-static void cpuset_do_move_task(struct task_struct *tsk,
-                                struct cgroup_scanner *scan)
-{
-        struct cgroup *new_cgroup = scan->data;
-
-        cgroup_lock();
-        cgroup_attach_task(new_cgroup, tsk);
-        cgroup_unlock();
-}
-
-/**
- * move_member_tasks_to_cpuset - move tasks from one cpuset to another
- * @from: cpuset in which the tasks currently reside
- * @to: cpuset to which the tasks will be moved
- *
- * Called with cpuset_mutex held
- * callback_mutex must not be held, as cpuset_attach() will take it.
- *
- * The cgroup_scan_tasks() function will scan all the tasks in a cgroup,
- * calling callback functions for each.
- */
-static void move_member_tasks_to_cpuset(struct cpuset *from, struct cpuset *to)
-{
-        struct cgroup_scanner scan;
-
-        scan.cg = from->css.cgroup;
-        scan.test_task = NULL; /* select all tasks in cgroup */
-        scan.process_task = cpuset_do_move_task;
-        scan.heap = NULL;
-        scan.data = to->css.cgroup;
-
-        if (cgroup_scan_tasks(&scan))
-                printk(KERN_ERR "move_member_tasks_to_cpuset: "
-                                "cgroup_scan_tasks failed\n");
-}
-
 /*
  * If CPU and/or memory hotplug handlers, below, unplug any CPUs
  * or memory nodes, we need to walk over the cpuset hierarchy,
@@ -2069,7 +2015,12 @@ static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
                         nodes_empty(parent->mems_allowed))
                 parent = parent_cs(parent);
 
-        move_member_tasks_to_cpuset(cs, parent);
+        if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {
+                rcu_read_lock();
+                printk(KERN_ERR "cpuset: failed to transfer tasks out of empty cpuset %s\n",
+                       cgroup_name(cs->css.cgroup));
+                rcu_read_unlock();
+        }
 }
 
 /**
@@ -2222,17 +2173,8 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
         flush_workqueue(cpuset_propagate_hotplug_wq);
 
         /* rebuild sched domains if cpus_allowed has changed */
-        if (cpus_updated) {
-                struct sched_domain_attr *attr;
-                cpumask_var_t *doms;
-                int ndoms;
-
-                mutex_lock(&cpuset_mutex);
-                ndoms = generate_sched_domains(&doms, &attr);
-                mutex_unlock(&cpuset_mutex);
-
-                partition_sched_domains(ndoms, doms, attr);
-        }
+        if (cpus_updated)
+                rebuild_sched_domains();
 }
 
 void cpuset_update_active_cpus(bool cpu_online)
@@ -2594,6 +2536,8 @@ int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
         return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
 }
 
+#define CPUSET_NODELIST_LEN     (256)
+
 /**
  * cpuset_print_task_mems_allowed - prints task's cpuset and mems_allowed
  * @task: pointer to task_struct of some task.
@@ -2604,25 +2548,22 @@ int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
  */
 void cpuset_print_task_mems_allowed(struct task_struct *tsk)
 {
-        struct dentry *dentry;
+         /* Statically allocated to prevent using excess stack. */
+        static char cpuset_nodelist[CPUSET_NODELIST_LEN];
+        static DEFINE_SPINLOCK(cpuset_buffer_lock);
 
-        dentry = task_cs(tsk)->css.cgroup->dentry;
-        spin_lock(&cpuset_buffer_lock);
+        struct cgroup *cgrp = task_cs(tsk)->css.cgroup;
 
-        if (!dentry) {
-                strcpy(cpuset_name, "/");
-        } else {
-                spin_lock(&dentry->d_lock);
-                strlcpy(cpuset_name, (const char *)dentry->d_name.name,
-                        CPUSET_NAME_LEN);
-                spin_unlock(&dentry->d_lock);
-        }
+        rcu_read_lock();
+        spin_lock(&cpuset_buffer_lock);
 
         nodelist_scnprintf(cpuset_nodelist, CPUSET_NODELIST_LEN,
                            tsk->mems_allowed);
         printk(KERN_INFO "%s cpuset=%s mems_allowed=%s\n",
-               tsk->comm, cpuset_name, cpuset_nodelist);
+               tsk->comm, cgroup_name(cgrp), cpuset_nodelist);
+
         spin_unlock(&cpuset_buffer_lock);
+        rcu_read_unlock();
 }
 
 /*