[PATCH RFC v4 0/3] tracing: Add trace events for preemption and irq disable/enable.

[PATCH RFC v4 0/3] tracing: Add trace events for preemption and irq disable/enable.

[Joel Fernandes]

These patches add trace events support for preempt and irq disable/enable
events.

Changes since v3 (link [1]):
Previously the patch series used the terms "critical section" but Peter
suggested that this name is confusing due to ambiguity, so I dropped calling it
that in this series. See discussion in [1]. I also dropped the "preemptirq"
combined event (which behaves similar to the preemptirqsoff tracer) for now and
will keep that for a later patch once we can get this foundation series in.

Here's an example of how Android's systrace will be using it to show atomic
sections as a gantt chart: http://imgur.com/download/TZplEVp

I also added a slightly unrelated fix for a config option (patch 3/3).

[1] https://patchwork.kernel.org/patch/9936045/

Joel Fernandes (3):
  trace/irqsoff: Prepare to add preempt and irq trace events
  trace: Add support for preempt and irq enable/disable events
  ftrace: Use correct config option for preemption debug

 include/linux/ftrace.h            |   7 +-
 include/linux/irqflags.h          |   4 +-
 include/trace/events/preemptirq.h |  62 +++++++++++++
 kernel/trace/Kconfig              |   9 ++
 kernel/trace/Makefile             |   1 +
 kernel/trace/trace_irqsoff.c      | 178 +++++++++++++++++++++++++++++++-------
 6 files changed, 226 insertions(+), 35 deletions(-)
 create mode 100644 include/trace/events/preemptirq.h

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@android.com
-- 
2.14.1.581.gf28d330327-goog

[PATCH RFC v4 1/3] tracing/irqsoff: Prepare to add preempt and irq trace events

[Joel Fernandes]

In preparation of adding irqsoff and preemptsoff enable and disable trace
events, move required functions and code to make it easier to add these events
in a later patch. This patch is just code movement and adding a few wrappers,
no functional change.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@android.com
Signed-off-by: Joel Fernandes <joelaf@google.com>
---
 kernel/trace/trace_irqsoff.c | 123 ++++++++++++++++++++++++++++++++-----------
 1 file changed, 93 insertions(+), 30 deletions(-)

diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 7758bc0617cb..38d65a0535e0 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -16,6 +16,7 @@
 
 #include "trace.h"
 
+#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
 static struct trace_array		*irqsoff_trace __read_mostly;
 static int				tracer_enabled __read_mostly;
 
@@ -432,19 +433,17 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip)
 }
 
 /* start and stop critical timings used to for stoppage (in idle) */
-void start_critical_timings(void)
+static inline void start_critical_timings_tracer(void)
 {
 	if (preempt_trace() || irq_trace())
 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
-EXPORT_SYMBOL_GPL(start_critical_timings);
 
-void stop_critical_timings(void)
+static inline void stop_critical_timings_tracer(void)
 {
 	if (preempt_trace() || irq_trace())
 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
-EXPORT_SYMBOL_GPL(stop_critical_timings);
 
 #ifdef CONFIG_IRQSOFF_TRACER
 #ifdef CONFIG_PROVE_LOCKING
@@ -462,64 +461,44 @@ void time_hardirqs_off(unsigned long a0, unsigned long a1)
 
 #else /* !CONFIG_PROVE_LOCKING */
 
-/*
- * Stubs:
- */
-
-void trace_softirqs_on(unsigned long ip)
-{
-}
-
-void trace_softirqs_off(unsigned long ip)
-{
-}
-
-inline void print_irqtrace_events(struct task_struct *curr)
-{
-}
-
 /*
  * We are only interested in hardirq on/off events:
  */
-void trace_hardirqs_on(void)
+static inline void tracer_hardirqs_on(void)
 {
 	if (!preempt_trace() && irq_trace())
 		stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
-EXPORT_SYMBOL(trace_hardirqs_on);
 
-void trace_hardirqs_off(void)
+static inline void tracer_hardirqs_off(void)
 {
 	if (!preempt_trace() && irq_trace())
 		start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
-EXPORT_SYMBOL(trace_hardirqs_off);
 
-__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
+static inline void tracer_hardirqs_on_caller(unsigned long caller_addr)
 {
 	if (!preempt_trace() && irq_trace())
 		stop_critical_timing(CALLER_ADDR0, caller_addr);
 }
-EXPORT_SYMBOL(trace_hardirqs_on_caller);
 
-__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
+static inline void tracer_hardirqs_off_caller(unsigned long caller_addr)
 {
 	if (!preempt_trace() && irq_trace())
 		start_critical_timing(CALLER_ADDR0, caller_addr);
 }
-EXPORT_SYMBOL(trace_hardirqs_off_caller);
 
 #endif /* CONFIG_PROVE_LOCKING */
 #endif /*  CONFIG_IRQSOFF_TRACER */
 
 #ifdef CONFIG_PREEMPT_TRACER
-void trace_preempt_on(unsigned long a0, unsigned long a1)
+static inline void tracer_preempt_on(unsigned long a0, unsigned long a1)
 {
 	if (preempt_trace() && !irq_trace())
 		stop_critical_timing(a0, a1);
 }
 
-void trace_preempt_off(unsigned long a0, unsigned long a1)
+static inline void tracer_preempt_off(unsigned long a0, unsigned long a1)
 {
 	if (preempt_trace() && !irq_trace())
 		start_critical_timing(a0, a1);
@@ -781,3 +760,87 @@ __init static int init_irqsoff_tracer(void)
 	return 0;
 }
 core_initcall(init_irqsoff_tracer);
+#else /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
+
+#define start_critical_timings_tracer() do { } while (0)
+#define stop_critical_timings_tracer() do { } while (0)
+
+#endif
+
+#ifndef CONFIG_IRQSOFF_TRACER
+#define tracer_hardirqs_on() do { } while (0)
+#define tracer_hardirqs_off() do { } while (0)
+#define tracer_hardirqs_on_caller(x) do { } while (0)
+#define tracer_hardirqs_off_caller(x) do { } while (0)
+#endif
+
+#ifndef CONFIG_PREEMPT_TRACER
+#define tracer_preempt_on(x, y) do { } while (0)
+#define tracer_preempt_off(x, y) do { } while (0)
+#endif
+
+void start_critical_timings(void)
+{
+	start_critical_timings_tracer();
+}
+EXPORT_SYMBOL_GPL(start_critical_timings);
+
+void stop_critical_timings(void)
+{
+	stop_critical_timings_tracer();
+}
+EXPORT_SYMBOL_GPL(stop_critical_timings);
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
+void trace_hardirqs_on(void)
+{
+	tracer_hardirqs_on();
+}
+EXPORT_SYMBOL(trace_hardirqs_on);
+
+void trace_hardirqs_off(void)
+{
+	tracer_hardirqs_off();
+}
+EXPORT_SYMBOL(trace_hardirqs_off);
+
+__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
+{
+	tracer_hardirqs_on_caller(caller_addr);
+}
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
+
+__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
+{
+	tracer_hardirqs_off_caller(caller_addr);
+}
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
+
+/*
+ * Stubs:
+ */
+
+void trace_softirqs_on(unsigned long ip)
+{
+}
+
+void trace_softirqs_off(unsigned long ip)
+{
+}
+
+inline void print_irqtrace_events(struct task_struct *curr)
+{
+}
+#endif
+
+#ifdef CONFIG_PREEMPT_TRACER
+void trace_preempt_on(unsigned long a0, unsigned long a1)
+{
+	tracer_preempt_on(a0, a1);
+}
+
+void trace_preempt_off(unsigned long a0, unsigned long a1)
+{
+	tracer_preempt_off(a0, a1);
+}
+#endif
-- 
2.14.1.581.gf28d330327-goog

[PATCH RFC v4 2/3] tracing: Add support for preempt and irq enable/disable events

[Joel Fernandes]

Preempt and irq trace events can be used for tracing the start and
end of an atomic section which can be used by a trace viewer like
systrace to graphically view the start and end of an atomic section and
correlate them with latencies and scheduling issues.

This also serves as a prelude to using synthetic events or probes to
rewrite the preempt and irqsoff tracers, along with numerous benefits of
using trace events features for these events.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zilstra <peterz@infradead.org>
Cc: kernel-team@android.com
Signed-off-by: Joel Fernandes <joelaf@google.com>
---
 include/linux/ftrace.h            |  3 +-
 include/linux/irqflags.h          |  4 +--
 include/trace/events/preemptirq.h | 62 +++++++++++++++++++++++++++++++++++++++
 kernel/trace/Kconfig              |  9 ++++++
 kernel/trace/Makefile             |  1 +
 kernel/trace/trace_irqsoff.c      | 57 ++++++++++++++++++++++++++++++++++-
 6 files changed, 132 insertions(+), 4 deletions(-)
 create mode 100644 include/trace/events/preemptirq.h

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 6383115e9d2c..5790ba7a85bd 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -742,7 +742,8 @@ static inline unsigned long get_lock_parent_ip(void)
   static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
 #endif
 
-#ifdef CONFIG_PREEMPT_TRACER
+#if defined(CONFIG_PREEMPT_TRACER) || \
+	(defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
   extern void trace_preempt_on(unsigned long a0, unsigned long a1);
   extern void trace_preempt_off(unsigned long a0, unsigned long a1);
 #else
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index 5dd1272d1ab2..6ad6732a4e98 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -44,8 +44,8 @@
 # define INIT_TRACE_IRQFLAGS
 #endif
 
-#if defined(CONFIG_IRQSOFF_TRACER) || \
-	defined(CONFIG_PREEMPT_TRACER)
+#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER) || \
+	defined(CONFIG_PREEMPTIRQ_EVENTS)
  extern void stop_critical_timings(void);
  extern void start_critical_timings(void);
 #else
diff --git a/include/trace/events/preemptirq.h b/include/trace/events/preemptirq.h
new file mode 100644
index 000000000000..601935e32cd1
--- /dev/null
+++ b/include/trace/events/preemptirq.h
@@ -0,0 +1,62 @@
+#ifdef CONFIG_PREEMPTIRQ_EVENTS
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM preemptirq
+
+#if !defined(_TRACE_PREEMPTIRQ_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PREEMPTIRQ_H
+
+#include <linux/ktime.h>
+#include <linux/tracepoint.h>
+#include <linux/string.h>
+#include <asm/sections.h>
+
+DECLARE_EVENT_CLASS(preemptirq_template,
+
+	TP_PROTO(unsigned long ip, unsigned long parent_ip),
+
+	TP_ARGS(ip, parent_ip),
+
+	TP_STRUCT__entry(
+		__field(u32, caller_offs)
+		__field(u32, parent_offs)
+	),
+
+	TP_fast_assign(
+		__entry->caller_offs = (u32)(ip - (unsigned long)_stext);
+		__entry->parent_offs = (u32)(parent_ip - (unsigned long)_stext);
+	),
+
+	TP_printk("caller=%pF parent=%pF\n",
+		  (void *)((unsigned long)(_stext) + __entry->caller_offs),
+		  (void *)((unsigned long)(_stext) + __entry->parent_offs))
+);
+
+DEFINE_EVENT(preemptirq_template, irq_disable,
+	     TP_PROTO(unsigned long ip, unsigned long parent_ip),
+	     TP_ARGS(ip, parent_ip));
+
+DEFINE_EVENT(preemptirq_template, irq_enable,
+	     TP_PROTO(unsigned long ip, unsigned long parent_ip),
+	     TP_ARGS(ip, parent_ip));
+
+DEFINE_EVENT(preemptirq_template, preempt_disable,
+	     TP_PROTO(unsigned long ip, unsigned long parent_ip),
+	     TP_ARGS(ip, parent_ip));
+
+DEFINE_EVENT(preemptirq_template, preempt_enable,
+	     TP_PROTO(unsigned long ip, unsigned long parent_ip),
+	     TP_ARGS(ip, parent_ip));
+
+#endif /* _TRACE_PREEMPTIRQ_H */
+
+#include <trace/define_trace.h>
+
+#else /* !CONFIG_PREEMPTIRQ_EVENTS */
+
+#define trace_irq_enable(...)
+#define trace_irq_disable(...)
+#define trace_preempt_enable(...)
+#define trace_preempt_disable(...)
+
+#endif
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 434c840e2d82..420666152de8 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -160,6 +160,15 @@ config FUNCTION_GRAPH_TRACER
 	  address on the current task structure into a stack of calls.
 
 
+config PREEMPTIRQ_EVENTS
+	bool "Enable trace events for preempt and irq disable/enable"
+	select TRACE_IRQFLAGS
+	default n
+	help
+	  Enable tracing of disable and enable events for preemption and irqs.
+	  For tracing preempt disable/enable events, CONFIG_DEBUG_PREEMPT must
+	  be enabled.
+
 config IRQSOFF_TRACER
 	bool "Interrupts-off Latency Tracer"
 	default n
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 90f2701d92a7..9f62eee61f14 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_TRACING) += trace_printk.o
 obj-$(CONFIG_TRACING_MAP) += tracing_map.o
 obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
 obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
+obj-$(CONFIG_PREEMPTIRQ_EVENTS) += trace_irqsoff.o
 obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
 obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 38d65a0535e0..89ff6bd685a2 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -16,12 +16,18 @@
 
 #include "trace.h"
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/preemptirq.h>
+
 #if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
 static struct trace_array		*irqsoff_trace __read_mostly;
 static int				tracer_enabled __read_mostly;
 
 static DEFINE_PER_CPU(int, tracing_cpu);
 
+static DEFINE_PER_CPU(int, tracing_irq_cpu);
+static DEFINE_PER_CPU(int, tracing_preempt_cpu);
+
 static DEFINE_RAW_SPINLOCK(max_trace_lock);
 
 enum {
@@ -781,12 +787,24 @@ core_initcall(init_irqsoff_tracer);
 
 void start_critical_timings(void)
 {
+	if (this_cpu_read(tracing_preempt_cpu))
+		trace_preempt_enable(CALLER_ADDR0, CALLER_ADDR1);
+
+	if (this_cpu_read(tracing_irq_cpu))
+		trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
+
 	start_critical_timings_tracer();
 }
 EXPORT_SYMBOL_GPL(start_critical_timings);
 
 void stop_critical_timings(void)
 {
+	if (this_cpu_read(tracing_preempt_cpu))
+		trace_preempt_disable(CALLER_ADDR0, CALLER_ADDR1);
+
+	if (this_cpu_read(tracing_irq_cpu))
+		trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
+
 	stop_critical_timings_tracer();
 }
 EXPORT_SYMBOL_GPL(stop_critical_timings);
@@ -794,24 +812,48 @@ EXPORT_SYMBOL_GPL(stop_critical_timings);
 #if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
 void trace_hardirqs_on(void)
 {
+	if (!this_cpu_read(tracing_irq_cpu))
+		return;
+
+	trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
 	tracer_hardirqs_on();
+
+	this_cpu_write(tracing_irq_cpu, 0);
 }
 EXPORT_SYMBOL(trace_hardirqs_on);
 
 void trace_hardirqs_off(void)
 {
+	if (this_cpu_read(tracing_irq_cpu))
+		return;
+
+	this_cpu_write(tracing_irq_cpu, 1);
+
+	trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
 	tracer_hardirqs_off();
 }
 EXPORT_SYMBOL(trace_hardirqs_off);
 
 __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
 {
+	if (!this_cpu_read(tracing_irq_cpu))
+		return;
+
+	trace_irq_enable(CALLER_ADDR0, caller_addr);
 	tracer_hardirqs_on_caller(caller_addr);
+
+	this_cpu_write(tracing_irq_cpu, 0);
 }
 EXPORT_SYMBOL(trace_hardirqs_on_caller);
 
 __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
 {
+	if (this_cpu_read(tracing_irq_cpu))
+		return;
+
+	this_cpu_write(tracing_irq_cpu, 1);
+
+	trace_irq_disable(CALLER_ADDR0, caller_addr);
 	tracer_hardirqs_off_caller(caller_addr);
 }
 EXPORT_SYMBOL(trace_hardirqs_off_caller);
@@ -833,14 +875,27 @@ inline void print_irqtrace_events(struct task_struct *curr)
 }
 #endif
 
-#ifdef CONFIG_PREEMPT_TRACER
+#if defined(CONFIG_PREEMPT_TRACER) || \
+	(defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
 void trace_preempt_on(unsigned long a0, unsigned long a1)
 {
+	if (!this_cpu_read(tracing_preempt_cpu))
+		return;
+
+	trace_preempt_enable(a0, a1);
 	tracer_preempt_on(a0, a1);
+
+	this_cpu_write(tracing_preempt_cpu, 0);
 }
 
 void trace_preempt_off(unsigned long a0, unsigned long a1)
 {
+	if (this_cpu_read(tracing_preempt_cpu))
+		return;
+
+	this_cpu_write(tracing_preempt_cpu, 1);
+
+	trace_preempt_disable(a0, a1);
 	tracer_preempt_off(a0, a1);
 }
 #endif
-- 
2.14.1.581.gf28d330327-goog

[PATCH RFC v4 3/3] ftrace: Use correct config option for preemption debug

[Joel Fernandes]

I notice that CONFIG_PREEMPT_DEBUG doesn't exist, though this code uses it. I
think it wants CONFIG_DEBUG_PREEMPT. Replace it with the same.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kernel-team@android.com
Signed-off-by: Joel Fernandes <joelaf@google.com>
---
 include/linux/ftrace.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 5790ba7a85bd..768e49b8c80f 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -307,7 +307,7 @@ DECLARE_PER_CPU(int, disable_stack_tracer);
 static inline void stack_tracer_disable(void)
 {
 	/* Preemption or interupts must be disabled */
-	if (IS_ENABLED(CONFIG_PREEMPT_DEBUG))
+	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
 		WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 	this_cpu_inc(disable_stack_tracer);
 }
@@ -320,7 +320,7 @@ static inline void stack_tracer_disable(void)
  */
 static inline void stack_tracer_enable(void)
 {
-	if (IS_ENABLED(CONFIG_PREEMPT_DEBUG))
+	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT))
 		WARN_ON_ONCE(!preempt_count() || !irqs_disabled());
 	this_cpu_dec(disable_stack_tracer);
 }
-- 
2.14.1.581.gf28d330327-goog

Re: [PATCH RFC v4 1/3] tracing/irqsoff: Prepare to add preempt and irq trace events

[Steven Rostedt]

On Wed,  6 Sep 2017 17:17:50 -0700
Joel Fernandes <joelaf@google.com> wrote:


> +#else /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
> +
> +#define start_critical_timings_tracer() do { } while (0)
> +#define stop_critical_timings_tracer() do { } while (0)
> +
> +#endif
> +
> +#ifndef CONFIG_IRQSOFF_TRACER
> +#define tracer_hardirqs_on() do { } while (0)
> +#define tracer_hardirqs_off() do { } while (0)
> +#define tracer_hardirqs_on_caller(x) do { } while (0)
> +#define tracer_hardirqs_off_caller(x) do { } while (0)
> +#endif
> +
> +#ifndef CONFIG_PREEMPT_TRACER
> +#define tracer_preempt_on(x, y) do { } while (0)
> +#define tracer_preempt_off(x, y) do { } while (0)
> +#endif

Is there a reason the above is #define and not static inline? The
preferred method is static inline as that allows the compiler to check
types. #define is used if one of the parameters has a struct or
something that is not defined.

-- Steve

Re: [PATCH RFC v4 1/3] tracing/irqsoff: Prepare to add preempt and irq trace events

[Joel Fernandes]

Hi Steven,

On Sun, Sep 10, 2017 at 2:06 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
> On Wed,  6 Sep 2017 17:17:50 -0700
> Joel Fernandes <joelaf@google.com> wrote:
>
>
>> +#else /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
>> +
>> +#define start_critical_timings_tracer() do { } while (0)
>> +#define stop_critical_timings_tracer() do { } while (0)
>> +
>> +#endif
>> +
>> +#ifndef CONFIG_IRQSOFF_TRACER
>> +#define tracer_hardirqs_on() do { } while (0)
>> +#define tracer_hardirqs_off() do { } while (0)
>> +#define tracer_hardirqs_on_caller(x) do { } while (0)
>> +#define tracer_hardirqs_off_caller(x) do { } while (0)
>> +#endif
>> +
>> +#ifndef CONFIG_PREEMPT_TRACER
>> +#define tracer_preempt_on(x, y) do { } while (0)
>> +#define tracer_preempt_off(x, y) do { } while (0)
>> +#endif
>
> Is there a reason the above is #define and not static inline? The
> preferred method is static inline as that allows the compiler to check
> types. #define is used if one of the parameters has a struct or
> something that is not defined.

Sure, I'll make use of static inline in the next version. thanks!

-Joel