diff options
| -rw-r--r-- | include/linux/ftrace.h | 16 | ||||
| -rw-r--r-- | kernel/trace/fgraph.c | 17 |
2 files changed, 18 insertions, 15 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 37b619185ec9..f15a4b76cbfc 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -9,6 +9,7 @@ #include <linux/trace_recursion.h> #include <linux/trace_clock.h> +#include <linux/jump_label.h> #include <linux/kallsyms.h> #include <linux/linkage.h> #include <linux/bitops.h> @@ -1015,7 +1016,20 @@ unsigned long ftrace_graph_ret_addr(struct task_struct *task, int *idx, extern int register_ftrace_graph(struct fgraph_ops *ops); extern void unregister_ftrace_graph(struct fgraph_ops *ops); -extern bool ftrace_graph_is_dead(void); +/** + * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called + * + * ftrace_graph_stop() is called when a severe error is detected in + * the function graph tracing. This function is called by the critical + * paths of function graph to keep those paths from doing any more harm. + */ +DECLARE_STATIC_KEY_FALSE(kill_ftrace_graph); + +static inline bool ftrace_graph_is_dead(void) +{ + return static_branch_unlikely(&kill_ftrace_graph); +} + extern void ftrace_graph_stop(void); /* The current handlers in use */ diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 19028e072cdb..8f4fb328133a 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -7,6 +7,7 @@ * * Highly modified by Steven Rostedt (VMware). */ +#include <linux/jump_label.h> #include <linux/suspend.h> #include <linux/ftrace.h> #include <linux/slab.h> @@ -23,25 +24,13 @@ #define ASSIGN_OPS_HASH(opsname, val) #endif -static bool kill_ftrace_graph; +DEFINE_STATIC_KEY_FALSE(kill_ftrace_graph); int ftrace_graph_active; /* Both enabled by default (can be cleared by function_graph tracer flags */ static bool fgraph_sleep_time = true; /** - * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called - * - * ftrace_graph_stop() is called when a severe error is detected in - * the function graph tracing. This function is called by the critical - * paths of function graph to keep those paths from doing any more harm. - */ -bool ftrace_graph_is_dead(void) -{ - return kill_ftrace_graph; -} - -/** * ftrace_graph_stop - set to permanently disable function graph tracing * * In case of an error int function graph tracing, this is called @@ -51,7 +40,7 @@ bool ftrace_graph_is_dead(void) */ void ftrace_graph_stop(void) { - kill_ftrace_graph = true; + static_branch_enable(&kill_ftrace_graph); } /* Add a function return address to the trace stack on thread info.*/ |