Upgrade to 4.4.50-rt62

[kvmfornfv.git] / kernel / kernel / cpuset.c

diff --git a/kernel/kernel/cpuset.c b/kernel/kernel/cpuset.c
index 2ade632..b271353 100644 (file)
--- a/kernel/kernel/cpuset.c
+++ b/kernel/kernel/cpuset.c
@@ -57,7 +57,6 @@
 #include <asm/uaccess.h>
 #include <linux/atomic.h>
 #include <linux/mutex.h>
-#include <linux/workqueue.h>
 #include <linux/cgroup.h>
 #include <linux/wait.h>
 
@@ -325,8 +324,7 @@ static struct file_system_type cpuset_fs_type = {
 /*
  * Return in pmask the portion of a cpusets's cpus_allowed that
  * are online.  If none are online, walk up the cpuset hierarchy
- * until we find one that does have some online cpus.  The top
- * cpuset always has some cpus online.
+ * until we find one that does have some online cpus.
  *
  * One way or another, we guarantee to return some non-empty subset
  * of cpu_online_mask.
@@ -335,8 +333,20 @@ static struct file_system_type cpuset_fs_type = {
  */
 static void guarantee_online_cpus(struct cpuset *cs, struct cpumask *pmask)
 {
-       while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask))
+       while (!cpumask_intersects(cs->effective_cpus, cpu_online_mask)) {
                cs = parent_cs(cs);
+               if (unlikely(!cs)) {
+                       /*
+                        * The top cpuset doesn't have any online cpu as a
+                        * consequence of a race between cpuset_hotplug_work
+                        * and cpu hotplug notifier.  But we know the top
+                        * cpuset's effective_cpus is on its way to to be
+                        * identical to cpu_online_mask.
+                        */
+                       cpumask_copy(pmask, cpu_online_mask);
+                       return;
+               }
+       }
        cpumask_and(pmask, cs->effective_cpus, cpu_online_mask);
 }
 
@@ -1015,7 +1025,7 @@ static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
        }
 }
 
-void cpuset_post_attach_flush(void)
+static void cpuset_post_attach(void)
 {
        flush_workqueue(cpuset_migrate_mm_wq);
 }
@@ -2075,6 +2085,20 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css)
        mutex_unlock(&cpuset_mutex);
 }
 
+/*
+ * Make sure the new task conform to the current state of its parent,
+ * which could have been changed by cpuset just after it inherits the
+ * state from the parent and before it sits on the cgroup's task list.
+ */
+void cpuset_fork(struct task_struct *task, void *priv)
+{
+       if (task_css_is_root(task, cpuset_cgrp_id))
+               return;
+
+       set_cpus_allowed_ptr(task, &current->cpus_allowed);
+       task->mems_allowed = current->mems_allowed;
+}
+
 struct cgroup_subsys cpuset_cgrp_subsys = {
        .css_alloc      = cpuset_css_alloc,
        .css_online     = cpuset_css_online,
@@ -2083,7 +2107,9 @@ struct cgroup_subsys cpuset_cgrp_subsys = {
        .can_attach     = cpuset_can_attach,
        .cancel_attach  = cpuset_cancel_attach,
        .attach         = cpuset_attach,
+       .post_attach    = cpuset_post_attach,
        .bind           = cpuset_bind,
+       .fork           = cpuset_fork,
        .legacy_cftypes = files,
        .early_init     = 1,
 };