rcu: Add RCU_CPU_STALL_VERBOSE to dump detailed per-task information

[safe/jmp/linux-2.6] / kernel / rcutree_plugin.h

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index aecfe37..3516de7 100644 (file)
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -312,6 +312,50 @@ EXPORT_SYMBOL_GPL(__rcu_read_unlock);
 
 #ifdef CONFIG_RCU_CPU_STALL_DETECTOR
 
+#ifdef CONFIG_RCU_CPU_STALL_VERBOSE
+
+/*
+ * Dump detailed information for all tasks blocking the current RCU
+ * grace period on the specified rcu_node structure.
+ */
+static void rcu_print_detail_task_stall_rnp(struct rcu_node *rnp)
+{
+       unsigned long flags;
+       struct list_head *lp;
+       int phase;
+       struct task_struct *t;
+
+       if (rcu_preempted_readers(rnp)) {
+               raw_spin_lock_irqsave(&rnp->lock, flags);
+               phase = rnp->gpnum & 0x1;
+               lp = &rnp->blocked_tasks[phase];
+               list_for_each_entry(t, lp, rcu_node_entry)
+                       sched_show_task(t);
+               raw_spin_unlock_irqrestore(&rnp->lock, flags);
+       }
+}
+
+/*
+ * Dump detailed information for all tasks blocking the current RCU
+ * grace period.
+ */
+static void rcu_print_detail_task_stall(struct rcu_state *rsp)
+{
+       struct rcu_node *rnp = rcu_get_root(rsp);
+
+       rcu_print_detail_task_stall_rnp(rnp);
+       rcu_for_each_leaf_node(rsp, rnp)
+               rcu_print_detail_task_stall_rnp(rnp);
+}
+
+#else /* #ifdef CONFIG_RCU_CPU_STALL_VERBOSE */
+
+static void rcu_print_detail_task_stall(struct rcu_state *rsp)
+{
+}
+
+#endif /* #else #ifdef CONFIG_RCU_CPU_STALL_VERBOSE */
+
 /*
  * Scan the current list of tasks blocked within RCU read-side critical
  * sections, printing out the tid of each.
@@ -764,6 +808,14 @@ static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags)
  * Because preemptable RCU does not exist, we never have to check for
  * tasks blocked within RCU read-side critical sections.
  */
+static void rcu_print_detail_task_stall(struct rcu_state *rsp)
+{
+}
+
+/*
+ * Because preemptable RCU does not exist, we never have to check for
+ * tasks blocked within RCU read-side critical sections.
+ */
 static void rcu_print_task_stall(struct rcu_node *rnp)
 {
 }