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-rw-r--r--include/linux/ftrace.h24
-rw-r--r--init/main.c4
-rw-r--r--kernel/trace/trace_boot.c28
3 files changed, 41 insertions, 15 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index e46a7b34037..4642959e5bd 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -234,6 +234,11 @@ ftrace_init_module(unsigned long *start, unsigned long *end) { }
#endif
+/*
+ * Structure which defines the trace of an initcall.
+ * You don't have to fill the func field since it is
+ * only used internally by the tracer.
+ */
struct boot_trace {
pid_t caller;
char func[KSYM_NAME_LEN];
@@ -244,13 +249,28 @@ struct boot_trace {
};
#ifdef CONFIG_BOOT_TRACER
+/* Append the trace on the ring-buffer */
extern void trace_boot(struct boot_trace *it, initcall_t fn);
+
+/* Tells the tracer that smp_pre_initcall is finished.
+ * So we can start the tracing
+ */
extern void start_boot_trace(void);
-extern void stop_boot_trace(void);
+
+/* Resume the tracing of other necessary events
+ * such as sched switches
+ */
+extern void enable_boot_trace(void);
+
+/* Suspend this tracing. Actually, only sched_switches tracing have
+ * to be suspended. Initcalls doesn't need it.)
+ */
+extern void disable_boot_trace(void);
#else
static inline void trace_boot(struct boot_trace *it, initcall_t fn) { }
static inline void start_boot_trace(void) { }
-static inline void stop_boot_trace(void) { }
+static inline void enable_boot_trace(void) { }
+static inline void disable_boot_trace(void) { }
#endif
diff --git a/init/main.c b/init/main.c
index 7e117a231af..4b03cd5656c 100644
--- a/init/main.c
+++ b/init/main.c
@@ -711,6 +711,7 @@ int do_one_initcall(initcall_t fn)
it.caller = task_pid_nr(current);
printk("calling %pF @ %i\n", fn, it.caller);
it.calltime = ktime_get();
+ enable_boot_trace();
}
it.result = fn();
@@ -722,6 +723,7 @@ int do_one_initcall(initcall_t fn)
printk("initcall %pF returned %d after %Ld usecs\n", fn,
it.result, it.duration);
trace_boot(&it, fn);
+ disable_boot_trace();
}
msgbuf[0] = 0;
@@ -882,7 +884,7 @@ static int __init kernel_init(void * unused)
* we're essentially up and running. Get rid of the
* initmem segments and start the user-mode stuff..
*/
- stop_boot_trace();
+
init_post();
return 0;
}
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index d0a5e50eeff..d104d5b4641 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -13,23 +13,29 @@
#include "trace.h"
static struct trace_array *boot_trace;
-static int trace_boot_enabled;
+static bool pre_initcalls_finished;
-
-/* Should be started after do_pre_smp_initcalls() in init/main.c */
+/* Tells the boot tracer that the pre_smp_initcalls are finished.
+ * So we are ready .
+ * It doesn't enable sched events tracing however.
+ * You have to call enable_boot_trace to do so.
+ */
void start_boot_trace(void)
{
- trace_boot_enabled = 1;
+ pre_initcalls_finished = true;
+}
+
+void enable_boot_trace(void)
+{
}
-void stop_boot_trace(void)
+void disable_boot_trace(void)
{
- trace_boot_enabled = 0;
}
void reset_boot_trace(struct trace_array *tr)
{
- stop_boot_trace();
+ disable_boot_trace();
}
static void boot_trace_init(struct trace_array *tr)
@@ -37,8 +43,6 @@ static void boot_trace_init(struct trace_array *tr)
int cpu;
boot_trace = tr;
- trace_boot_enabled = 0;
-
for_each_cpu_mask(cpu, cpu_possible_map)
tracing_reset(tr, cpu);
}
@@ -46,9 +50,9 @@ static void boot_trace_init(struct trace_array *tr)
static void boot_trace_ctrl_update(struct trace_array *tr)
{
if (tr->ctrl)
- start_boot_trace();
+ enable_boot_trace();
else
- stop_boot_trace();
+ disable_boot_trace();
}
static enum print_line_t initcall_print_line(struct trace_iterator *iter)
@@ -99,7 +103,7 @@ void trace_boot(struct boot_trace *it, initcall_t fn)
unsigned long irq_flags;
struct trace_array *tr = boot_trace;
- if (!trace_boot_enabled)
+ if (!pre_initcalls_finished)
return;
/* Get its name now since this function could