[PATCH v3 tip/core/rcu 18/34] rcu-tasks: Add RCU tasks to rcutorture writer stall output

paulmck
2020-03-27T22:25:13Z

This commit adds state for each RCU-tasks flavor to the rcutorture
writer stall output. The initial state is minimal, but you have to
start somewhere.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
[ paulmck: Fixes based on feedback from kbuild test robot. ]
---
kernel/rcu/rcu.h | 1 +
kernel/rcu/tasks.h | 45 +++++++++++++++++++++++++++++++++++++++++++--
kernel/rcu/tree_stall.h | 2 +-
3 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 72903867..e1089fd 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -431,6 +431,7 @@ bool rcu_gp_is_expedited(void); /* Internal RCU use. */
void rcu_expedite_gp(void);
void rcu_unexpedite_gp(void);
void rcupdate_announce_bootup_oddness(void);
+void show_rcu_tasks_gp_kthreads(void);
void rcu_request_urgent_qs_task(struct task_struct *t);
#endif /* #else #ifdef CONFIG_TINY_RCU */

diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index b52a640..7ce9a60 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -219,6 +219,16 @@ static void __init rcu_tasks_bootup_oddness(void)

#endif /* #ifndef CONFIG_TINY_RCU */

+/* Dump out rcutorture-relevant state common to all RCU-tasks flavors. */
+static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)
+{
+ pr_info("%s %c%c %s\n",
+ rtp->kname,
+ ".k"[!!data_race(rtp->kthread_ptr)],
+ ".C"[!!data_race(rtp->cbs_head)],
+ s);
+}
+
#ifdef CONFIG_TASKS_RCU

////////////////////////////////////////////////////////////////////////
@@ -482,7 +492,14 @@ static int __init rcu_spawn_tasks_kthread(void)
}
core_initcall(rcu_spawn_tasks_kthread);

-#endif /* #ifdef CONFIG_TASKS_RCU */
+static void show_rcu_tasks_classic_gp_kthread(void)
+{
+ show_rcu_tasks_generic_gp_kthread(&rcu_tasks, "");
+}
+
+#else /* #ifdef CONFIG_TASKS_RCU */
+static void show_rcu_tasks_classic_gp_kthread(void) { }
+#endif /* #else #ifdef CONFIG_TASKS_RCU */

#ifdef CONFIG_TASKS_RUDE_RCU

@@ -578,7 +595,14 @@ static int __init rcu_spawn_tasks_rude_kthread(void)
}
core_initcall(rcu_spawn_tasks_rude_kthread);

-#endif /* #ifdef CONFIG_TASKS_RUDE_RCU */
+static void show_rcu_tasks_rude_gp_kthread(void)
+{
+ show_rcu_tasks_generic_gp_kthread(&rcu_tasks_rude, "");
+}
+
+#else /* #ifdef CONFIG_TASKS_RUDE_RCU */
+static void show_rcu_tasks_rude_gp_kthread(void) {}
+#endif /* #else #ifdef CONFIG_TASKS_RUDE_RCU */

////////////////////////////////////////////////////////////////////////
//
@@ -978,10 +1002,27 @@ static int __init rcu_spawn_tasks_trace_kthread(void)
}
core_initcall(rcu_spawn_tasks_trace_kthread);

+static void show_rcu_tasks_trace_gp_kthread(void)
+{
+ char buf[32];
+
+ sprintf(buf, "N%d", atomic_read(&trc_n_readers_need_end));
+ show_rcu_tasks_generic_gp_kthread(&rcu_tasks_trace, buf);
+}
+
#else /* #ifdef CONFIG_TASKS_TRACE_RCU */
void exit_tasks_rcu_finish_trace(struct task_struct *t) { }
+static inline void show_rcu_tasks_trace_gp_kthread(void) {}
#endif /* #else #ifdef CONFIG_TASKS_TRACE_RCU */

+void show_rcu_tasks_gp_kthreads(void)
+{
+ show_rcu_tasks_classic_gp_kthread();
+ show_rcu_tasks_rude_gp_kthread();
+ show_rcu_tasks_trace_gp_kthread();
+}
+
#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
static inline void rcu_tasks_bootup_oddness(void) {}
+void show_rcu_tasks_gp_kthreads(void) {}
#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index e19487d..ec8e985 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -649,7 +649,7 @@ void show_rcu_gp_kthreads(void)
if (rcu_segcblist_is_offloaded(&rdp->cblist))
show_rcu_nocb_state(rdp);
}
- /* sched_show_task(rcu_state.gp_kthread); */
+ show_rcu_tasks_gp_kthreads();
}
EXPORT_SYMBOL_GPL(show_rcu_gp_kthreads);

--
2.9.5