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-rw-r--r--kernel/trace/trace.c62
-rw-r--r--kernel/trace/trace.h25
-rw-r--r--kernel/trace/trace_functions.c1
-rw-r--r--kernel/trace/trace_functions_graph.c1
-rw-r--r--kernel/trace/trace_sched_switch.c1
-rw-r--r--kernel/trace/trace_sched_wakeup.c1
6 files changed, 67 insertions, 24 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index dc61e82faad..881a94474d7 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -499,6 +499,9 @@ __acquires(kernel_lock)
else
if (!type->flags->opts)
type->flags->opts = dummy_tracer_opt;
+ if (!type->wait_pipe)
+ type->wait_pipe = default_wait_pipe;
+
#ifdef CONFIG_FTRACE_STARTUP_TEST
if (type->selftest && !tracing_selftest_disabled) {
@@ -1064,7 +1067,10 @@ tracing_sched_wakeup_trace(struct trace_array *tr,
entry->next_prio = wakee->prio;
entry->next_state = wakee->state;
entry->next_cpu = task_cpu(wakee);
- trace_buffer_unlock_commit(tr, event, flags, pc);
+
+ ring_buffer_unlock_commit(tr->buffer, event);
+ ftrace_trace_stack(tr, flags, 6, pc);
+ ftrace_trace_userstack(tr, flags, pc);
}
void
@@ -2392,6 +2398,38 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table)
}
}
+
+void default_wait_pipe(struct trace_iterator *iter)
+{
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE);
+
+ if (trace_empty(iter))
+ schedule();
+
+ finish_wait(&trace_wait, &wait);
+}
+
+/*
+ * This is a make-shift waitqueue.
+ * A tracer might use this callback on some rare cases:
+ *
+ * 1) the current tracer might hold the runqueue lock when it wakes up
+ * a reader, hence a deadlock (sched, function, and function graph tracers)
+ * 2) the function tracers, trace all functions, we don't want
+ * the overhead of calling wake_up and friends
+ * (and tracing them too)
+ *
+ * Anyway, this is really very primitive wakeup.
+ */
+void poll_wait_pipe(struct trace_iterator *iter)
+{
+ set_current_state(TASK_INTERRUPTIBLE);
+ /* sleep for 100 msecs, and try again. */
+ schedule_timeout(HZ / 10);
+}
+
/* Must be called with trace_types_lock mutex held. */
static int tracing_wait_pipe(struct file *filp)
{
@@ -2403,30 +2441,14 @@ static int tracing_wait_pipe(struct file *filp)
return -EAGAIN;
}
- /*
- * This is a make-shift waitqueue. The reason we don't use
- * an actual wait queue is because:
- * 1) we only ever have one waiter
- * 2) the tracing, traces all functions, we don't want
- * the overhead of calling wake_up and friends
- * (and tracing them too)
- * Anyway, this is really very primitive wakeup.
- */
- set_current_state(TASK_INTERRUPTIBLE);
- iter->tr->waiter = current;
-
mutex_unlock(&trace_types_lock);
- /* sleep for 100 msecs, and try again. */
- schedule_timeout(HZ/10);
+ iter->trace->wait_pipe(iter);
mutex_lock(&trace_types_lock);
- iter->tr->waiter = NULL;
-
- if (signal_pending(current)) {
+ if (signal_pending(current))
return -EINTR;
- }
if (iter->trace != current_trace)
return 0;
@@ -2442,8 +2464,6 @@ static int tracing_wait_pipe(struct file *filp)
*/
if (!tracer_enabled && iter->pos)
break;
-
- continue;
}
return 1;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index dbff0207b21..eed732c151f 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -337,18 +337,34 @@ struct tracer_flags {
#define TRACER_OPT(s, b) .name = #s, .bit = b
-/*
- * A specific tracer, represented by methods that operate on a trace array:
+/**
+ * struct tracer - a specific tracer and its callbacks to interact with debugfs
+ * @name: the name chosen to select it on the available_tracers file
+ * @init: called when one switches to this tracer (echo name > current_tracer)
+ * @reset: called when one switches to another tracer
+ * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
+ * @stop: called when tracing is paused (echo 0 > tracing_enabled)
+ * @open: called when the trace file is opened
+ * @pipe_open: called when the trace_pipe file is opened
+ * @wait_pipe: override how the user waits for traces on trace_pipe
+ * @close: called when the trace file is released
+ * @read: override the default read callback on trace_pipe
+ * @splice_read: override the default splice_read callback on trace_pipe
+ * @selftest: selftest to run on boot (see trace_selftest.c)
+ * @print_headers: override the first lines that describe your columns
+ * @print_line: callback that prints a trace
+ * @set_flag: signals one of your private flags changed (trace_options file)
+ * @flags: your private flags
*/
struct tracer {
const char *name;
- /* Your tracer should raise a warning if init fails */
int (*init)(struct trace_array *tr);
void (*reset)(struct trace_array *tr);
void (*start)(struct trace_array *tr);
void (*stop)(struct trace_array *tr);
void (*open)(struct trace_iterator *iter);
void (*pipe_open)(struct trace_iterator *iter);
+ void (*wait_pipe)(struct trace_iterator *iter);
void (*close)(struct trace_iterator *iter);
ssize_t (*read)(struct trace_iterator *iter,
struct file *filp, char __user *ubuf,
@@ -432,6 +448,9 @@ void tracing_generic_entry_update(struct trace_entry *entry,
unsigned long flags,
int pc);
+void default_wait_pipe(struct trace_iterator *iter);
+void poll_wait_pipe(struct trace_iterator *iter);
+
void ftrace(struct trace_array *tr,
struct trace_array_cpu *data,
unsigned long ip,
diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 4c113a8c466..c9a0b7df44f 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -225,6 +225,7 @@ static struct tracer function_trace __read_mostly =
.init = function_trace_init,
.reset = function_trace_reset,
.start = function_trace_start,
+ .wait_pipe = poll_wait_pipe,
.flags = &func_flags,
.set_flag = func_set_flag,
#ifdef CONFIG_FTRACE_SELFTEST
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 519a0cab153..0ff5cb66190 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -757,6 +757,7 @@ static struct tracer graph_trace __read_mostly = {
.name = "function_graph",
.open = graph_trace_open,
.close = graph_trace_close,
+ .wait_pipe = poll_wait_pipe,
.init = graph_trace_init,
.reset = graph_trace_reset,
.print_line = print_graph_function,
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 82fbb5a2df8..77132c2cf3d 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -221,6 +221,7 @@ static struct tracer sched_switch_trace __read_mostly =
.reset = sched_switch_trace_reset,
.start = sched_switch_trace_start,
.stop = sched_switch_trace_stop,
+ .wait_pipe = poll_wait_pipe,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_sched_switch,
#endif
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 276c51aaf31..db55f7aaa64 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -380,6 +380,7 @@ static struct tracer wakeup_rt_tracer __read_mostly =
.reset = wakeup_tracer_reset,
.start = wakeup_tracer_start,
.stop = wakeup_tracer_stop,
+ .wait_pipe = poll_wait_pipe,
.print_max = 1,
#ifdef CONFIG_FTRACE_SELFTEST
.selftest = trace_selftest_startup_wakeup,