Merge branch 'tracing/fastboot' into tracing/ftrace
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index e46a7b3..4642959 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -234,6 +234,11 @@
#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 @@
};
#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 7e117a2..4b03cd5 100644
--- a/init/main.c
+++ b/init/main.c
@@ -711,6 +711,7 @@
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 @@
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 @@
* 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.c b/kernel/trace/trace.c
index d576dbd..29ab40a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3285,6 +3285,8 @@
register_tracer(&nop_trace);
#ifdef CONFIG_BOOT_TRACER
+ /* We don't want to launch sched_switch tracer yet */
+ global_trace.ctrl = 0;
register_tracer(&boot_tracer);
current_trace = &boot_tracer;
current_trace->init(&global_trace);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index bb547e9..cc14a6b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -49,6 +49,7 @@
unsigned long parent_ip;
};
extern struct tracer boot_tracer;
+extern struct tracer sched_switch_trace; /* Used by the boot tracer */
/*
* Context switch trace entry - which task (and prio) we switched from/to:
diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index d0a5e50..bd5046c 100644
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -13,23 +13,33 @@
#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 stop_boot_trace(void)
+void enable_boot_trace(void)
{
- trace_boot_enabled = 0;
+ if (pre_initcalls_finished)
+ tracing_start_cmdline_record();
}
-void reset_boot_trace(struct trace_array *tr)
+void disable_boot_trace(void)
{
- stop_boot_trace();
+ if (pre_initcalls_finished)
+ tracing_stop_cmdline_record();
+}
+
+static void reset_boot_trace(struct trace_array *tr)
+{
+ sched_switch_trace.reset(tr);
}
static void boot_trace_init(struct trace_array *tr)
@@ -37,18 +47,18 @@
int cpu;
boot_trace = tr;
- trace_boot_enabled = 0;
-
for_each_cpu_mask(cpu, cpu_possible_map)
tracing_reset(tr, cpu);
+
+ sched_switch_trace.init(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 +109,7 @@
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
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index b8f56be..888944d 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -16,7 +16,8 @@
static struct trace_array *ctx_trace;
static int __read_mostly tracer_enabled;
-static atomic_t sched_ref;
+static int sched_ref;
+static DEFINE_MUTEX(sched_register_mutex);
static void
probe_sched_switch(struct rq *__rq, struct task_struct *prev,
@@ -27,7 +28,7 @@
int cpu;
int pc;
- if (!atomic_read(&sched_ref))
+ if (!sched_ref)
return;
tracing_record_cmdline(prev);
@@ -123,20 +124,22 @@
static void tracing_start_sched_switch(void)
{
- long ref;
-
- ref = atomic_inc_return(&sched_ref);
- if (ref == 1)
+ mutex_lock(&sched_register_mutex);
+ if (!(sched_ref++)) {
+ tracer_enabled = 1;
tracing_sched_register();
+ }
+ mutex_unlock(&sched_register_mutex);
}
static void tracing_stop_sched_switch(void)
{
- long ref;
-
- ref = atomic_dec_and_test(&sched_ref);
- if (ref)
+ mutex_lock(&sched_register_mutex);
+ if (!(--sched_ref)) {
tracing_sched_unregister();
+ tracer_enabled = 0;
+ }
+ mutex_unlock(&sched_register_mutex);
}
void tracing_start_cmdline_record(void)
@@ -153,12 +156,10 @@
{
sched_switch_reset(tr);
tracing_start_cmdline_record();
- tracer_enabled = 1;
}
static void stop_sched_trace(struct trace_array *tr)
{
- tracer_enabled = 0;
tracing_stop_cmdline_record();
}
@@ -172,7 +173,7 @@
static void sched_switch_trace_reset(struct trace_array *tr)
{
- if (tr->ctrl)
+ if (tr->ctrl && sched_ref)
stop_sched_trace(tr);
}
@@ -185,7 +186,7 @@
stop_sched_trace(tr);
}
-static struct tracer sched_switch_trace __read_mostly =
+struct tracer sched_switch_trace __read_mostly =
{
.name = "sched_switch",
.init = sched_switch_trace_init,
@@ -198,14 +199,6 @@
__init static int init_sched_switch_trace(void)
{
- int ret = 0;
-
- if (atomic_read(&sched_ref))
- ret = tracing_sched_register();
- if (ret) {
- pr_info("error registering scheduler trace\n");
- return ret;
- }
return register_tracer(&sched_switch_trace);
}
device_initcall(init_sched_switch_trace);
