From 6508fa761c330a1d2b4ae36199d08dbcb70e3ddb Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Fri, 18 Jul 2014 15:17:27 +0400 Subject: [PATCH] tracing: let user specify tracing_thresh after selecting function_graph Currently, tracing_thresh works only if we specify it before selecting function_graph tracer. If we do the opposite, tracing_thresh will change it's value, but it will not be applied. To fix it, we add update_thresh callback which is called whenever tracing_thresh is updated and for function_graph tracer we register handler which reinitializes tracer depending on tracing_thresh. Link: http://lkml.kernel.org/p/20140718111727.GA3206@stfomichev-desktop.yandex.net Signed-off-by: Stanislav Fomichev Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 65 +++++++++++++++++++++++++--- kernel/trace/trace.h | 2 + kernel/trace/trace_functions_graph.c | 7 +++ 3 files changed, 67 insertions(+), 7 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4a343db45d4e..2752147ed317 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4201,10 +4201,9 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf, } static ssize_t -tracing_max_lat_read(struct file *filp, char __user *ubuf, - size_t cnt, loff_t *ppos) +tracing_nsecs_read(unsigned long *ptr, char __user *ubuf, + size_t cnt, loff_t *ppos) { - unsigned long *ptr = filp->private_data; char buf[64]; int r; @@ -4216,10 +4215,9 @@ tracing_max_lat_read(struct file *filp, char __user *ubuf, } static ssize_t -tracing_max_lat_write(struct file *filp, const char __user *ubuf, - size_t cnt, loff_t *ppos) +tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf, + size_t cnt, loff_t *ppos) { - unsigned long *ptr = filp->private_data; unsigned long val; int ret; @@ -4232,6 +4230,52 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf, return cnt; } +static ssize_t +tracing_thresh_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos); +} + +static ssize_t +tracing_thresh_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + int ret; + + mutex_lock(&trace_types_lock); + ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos); + if (ret < 0) + goto out; + + if (tr->current_trace->update_thresh) { + ret = tr->current_trace->update_thresh(tr); + if (ret < 0) + goto out; + } + + ret = cnt; +out: + mutex_unlock(&trace_types_lock); + + return ret; +} + +static ssize_t +tracing_max_lat_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos); +} + +static ssize_t +tracing_max_lat_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos); +} + static int tracing_open_pipe(struct inode *inode, struct file *filp) { struct trace_array *tr = inode->i_private; @@ -5133,6 +5177,13 @@ static int snapshot_raw_open(struct inode *inode, struct file *filp) #endif /* CONFIG_TRACER_SNAPSHOT */ +static const struct file_operations tracing_thresh_fops = { + .open = tracing_open_generic, + .read = tracing_thresh_read, + .write = tracing_thresh_write, + .llseek = generic_file_llseek, +}; + static const struct file_operations tracing_max_lat_fops = { .open = tracing_open_generic, .read = tracing_max_lat_read, @@ -6494,7 +6545,7 @@ static __init int tracer_init_debugfs(void) init_tracer_debugfs(&global_trace, d_tracer); trace_create_file("tracing_thresh", 0644, d_tracer, - &tracing_thresh, &tracing_max_lat_fops); + &global_trace, &tracing_thresh_fops); trace_create_file("README", 0444, d_tracer, NULL, &tracing_readme_fops); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9258f5a815db..385391fb1d3b 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -339,6 +339,7 @@ struct tracer_flags { * @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) + * @update_thresh: called when tracing_thresh is updated * @open: called when the trace file is opened * @pipe_open: called when the trace_pipe file is opened * @close: called when the trace file is released @@ -357,6 +358,7 @@ struct tracer { void (*reset)(struct trace_array *tr); void (*start)(struct trace_array *tr); void (*stop)(struct trace_array *tr); + int (*update_thresh)(struct trace_array *tr); void (*open)(struct trace_iterator *iter); void (*pipe_open)(struct trace_iterator *iter); void (*close)(struct trace_iterator *iter); diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 2c944e6c4a9d..74d98820497c 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -475,6 +475,12 @@ static void graph_trace_reset(struct trace_array *tr) unregister_ftrace_graph(); } +int graph_trace_update_thresh(struct trace_array *tr) +{ + graph_trace_reset(tr); + return graph_trace_init(tr); +} + static int max_bytes_for_cpu; static enum print_line_t @@ -1525,6 +1531,7 @@ static struct trace_event graph_trace_ret_event = { static struct tracer graph_trace __tracer_data = { .name = "function_graph", + .update_thresh = graph_trace_update_thresh, .open = graph_trace_open, .pipe_open = graph_trace_open, .close = graph_trace_close, -- 2.39.5