1 files changed, 34 insertions, 0 deletions

diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 39c1a4c1c5a9..345ace5117de 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -240,6 +240,17 @@ static struct cpuset top_cpuset = {
 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);
+
+/*
  * This is ugly, but preserves the userspace API for existing cpuset
  * users. If someone tries to mount the "cpuset" filesystem, we
  * silently switch it to mount "cgroup" instead
@@ -2356,6 +2367,29 @@ int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
         return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
 }
 
+/**
+ * cpuset_print_task_mems_allowed - prints task's cpuset and mems_allowed
+ * @task: pointer to task_struct of some task.
+ *
+ * Description: Prints @task's name, cpuset name, and cached copy of its
+ * mems_allowed to the kernel log.  Must hold task_lock(task) to allow
+ * dereferencing task_cs(task).
+ */
+void cpuset_print_task_mems_allowed(struct task_struct *tsk)
+{
+        struct dentry *dentry;
+
+        dentry = task_cs(tsk)->css.cgroup->dentry;
+        spin_lock(&cpuset_buffer_lock);
+        snprintf(cpuset_name, CPUSET_NAME_LEN,
+                 dentry ? (const char *)dentry->d_name.name : "/");
+        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);
+        spin_unlock(&cpuset_buffer_lock);
+}
+
 /*
  * Collection of memory_pressure is suppressed unless
  * this flag is enabled by writing "1" to the special