diff options
| -rw-r--r-- | kernel/trace/trace.c | 62 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 25 | ||||
| -rw-r--r-- | kernel/trace/trace_functions.c | 1 | ||||
| -rw-r--r-- | kernel/trace/trace_functions_graph.c | 1 | ||||
| -rw-r--r-- | kernel/trace/trace_sched_switch.c | 1 | ||||
| -rw-r--r-- | kernel/trace/trace_sched_wakeup.c | 1 |
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, |