ftrace: Use synchronize_rcu_tasks_rude() instead of ftrace_sync()
This commit replaces the schedule_on_each_cpu(ftrace_sync) instances
with synchronize_rcu_tasks_rude().
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
[ paulmck: Make Kconfig adjustments noted by kbuild test robot. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 402eef8..ae69010 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -158,6 +158,7 @@
select CONTEXT_SWITCH_TRACER
select GLOB
select TASKS_RCU if PREEMPTION
+ select TASKS_RUDE_RCU
help
Enable the kernel to trace every kernel function. This is done
by using a compiler feature to insert a small, 5-byte No-Operation
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fd81c7d..260992c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -150,17 +150,6 @@
op->saved_func(ip, parent_ip, op, regs);
}
-static void ftrace_sync(struct work_struct *work)
-{
- /*
- * This function is just a stub to implement a hard force
- * of synchronize_rcu(). This requires synchronizing
- * tasks even in userspace and idle.
- *
- * Yes, function tracing is rude.
- */
-}
-
static void ftrace_sync_ipi(void *data)
{
/* Probably not needed, but do it anyway */
@@ -246,7 +235,7 @@
* Make sure all CPUs see this. Yes this is slow, but static
* tracing is slow and nasty to have enabled.
*/
- schedule_on_each_cpu(ftrace_sync);
+ synchronize_rcu_tasks_rude();
/* Now all cpus are using the list ops. */
function_trace_op = set_function_trace_op;
/* Make sure the function_trace_op is visible on all CPUs */
@@ -2922,7 +2911,7 @@
* infrastructure to do the synchronization, thus we must do it
* ourselves.
*/
- schedule_on_each_cpu(ftrace_sync);
+ synchronize_rcu_tasks_rude();
/*
* When the kernel is preeptive, tasks can be preempted
@@ -5877,7 +5866,7 @@
* infrastructure to do the synchronization, thus we must do it
* ourselves.
*/
- schedule_on_each_cpu(ftrace_sync);
+ synchronize_rcu_tasks_rude();
free_ftrace_hash(old_hash);
}
