tracing: Do not trace in irq when funcgraph-irq option is zero

When the function graph tracer funcgraph-irq option is zero, disable tracing in IRQs. This makes the option have two effects. 1) When reading the trace file, do not display the functions that happen in interrupt context (when detected) 2) [*new*] When recording a trace, skip those that are detected to be in interrupt by the 'in_irq()' function Note, in_irq() is updated at irq_enter() and irq_exit(). There are still functions that are recorded by the function graph tracer that is in interrupt context but outside the irq_enter/exit() routines. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

tracing: Do not trace in irq when funcgraph-irq option is zero
When the function graph tracer funcgraph-irq option is zero, disable tracing in IRQs. This makes the option have two effects. 1) When reading the trace file, do not display the functions that happen in interrupt context (when detected) 2) [*new*] When recording a trace, skip those that are detected to be in interrupt by the 'in_irq()' function Note, in_irq() is updated at irq_enter() and irq_exit(). There are still functions that are recorded by the function graph tracer that is in interrupt context but outside the irq_enter/exit() routines. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt · Steven Rostedt
1 parent 2bd16212b8
Showing 1 changed file with 22 additions and 1 deletions Side-by-side Diff
kernel/trace/trace_functions_graph.c
@@ -15,6 +15,9 @@
 #include "trace.h"
 #include "trace_output.h"
  
+/* When set, irq functions will be ignored */
+static int ftrace_graph_skip_irqs;
+
 struct fgraph_cpu_data {
 	pid_t		last_pid;
 	int		depth;
@@ -208,6 +211,14 @@
 	return 1;
 }
  
+static inline int ftrace_graph_ignore_irqs(void)
+{
+	if (!ftrace_graph_skip_irqs)
+		return 0;
+
+	return in_irq();
+}
+
 int trace_graph_entry(struct ftrace_graph_ent *trace)
 {
 	struct trace_array *tr = graph_array;
@@ -222,7 +233,8 @@
 		return 0;
  
 	/* trace it when it is-nested-in or is a function enabled. */
-	if (!(trace->depth || ftrace_graph_addr(trace->func)))
+	if (!(trace->depth || ftrace_graph_addr(trace->func)) ||
+	      ftrace_graph_ignore_irqs())
 		return 0;
  
 	local_irq_save(flags);
@@ -1334,6 +1346,14 @@
 	}
 }
  
+static int func_graph_set_flag(u32 old_flags, u32 bit, int set)
+{
+	if (bit == TRACE_GRAPH_PRINT_IRQS)
+		ftrace_graph_skip_irqs = !set;
+
+	return 0;
+}
+
 static struct trace_event_functions graph_functions = {
 	.trace		= print_graph_function_event,
 };
@@ -1360,6 +1380,7 @@
 	.print_line	= print_graph_function,
 	.print_header	= print_graph_headers,
 	.flags		= &tracer_flags,
+	.set_flag	= func_graph_set_flag,
 #ifdef CONFIG_FTRACE_SELFTEST
 	.selftest	= trace_selftest_startup_function_graph,
 #endif
...	...	@@ -15,6 +15,9 @@
15	15	#include "trace.h"
16	16	#include "trace_output.h"
17	17
	18	+/* When set, irq functions will be ignored */
	19	+static int ftrace_graph_skip_irqs;
	20	+
18	21	struct fgraph_cpu_data {
19	22	pid_t last_pid;
20	23	int depth;
...	...	@@ -208,6 +211,14 @@
208	211	return 1;
209	212	}
210	213
	214	+static inline int ftrace_graph_ignore_irqs(void)
	215	+{
	216	+ if (!ftrace_graph_skip_irqs)
	217	+ return 0;
	218	+
	219	+ return in_irq();
	220	+}
	221	+
211	222	int trace_graph_entry(struct ftrace_graph_ent *trace)
212	223	{
213	224	struct trace_array *tr = graph_array;
...	...	@@ -222,7 +233,8 @@
222	233	return 0;
223	234
224	235	/* trace it when it is-nested-in or is a function enabled. */
225		- if (!(trace->depth \|\| ftrace_graph_addr(trace->func)))
	236	+ if (!(trace->depth \|\| ftrace_graph_addr(trace->func)) \|\|
	237	+ ftrace_graph_ignore_irqs())
226	238	return 0;
227	239
228	240	local_irq_save(flags);
...	...	@@ -1334,6 +1346,14 @@
1334	1346	}
1335	1347	}
1336	1348
	1349	+static int func_graph_set_flag(u32 old_flags, u32 bit, int set)
	1350	+{
	1351	+ if (bit == TRACE_GRAPH_PRINT_IRQS)
	1352	+ ftrace_graph_skip_irqs = !set;
	1353	+
	1354	+ return 0;
	1355	+}
	1356	+
1337	1357	static struct trace_event_functions graph_functions = {
1338	1358	.trace = print_graph_function_event,
1339	1359	};
...	...	@@ -1360,6 +1380,7 @@
1360	1380	.print_line = print_graph_function,
1361	1381	.print_header = print_graph_headers,
1362	1382	.flags = &tracer_flags,
	1383	+ .set_flag = func_graph_set_flag,
1363	1384	#ifdef CONFIG_FTRACE_SELFTEST
1364	1385	.selftest = trace_selftest_startup_function_graph,
1365	1386	#endif