Messages in this thread | | | Date | Wed, 25 Feb 2009 07:59:49 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 4/4] tracing: make event directory structure |
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On Tue, Feb 24, 2009 at 09:56:12PM -0500, Steven Rostedt wrote: > From: Steven Rostedt <srostedt@redhat.com> > > This patch adds the directory /debug/tracing/events/ that will contain > all the registered trace points. > > # ls /debug/tracing/events/ > sched_kthread_stop sched_process_fork sched_switch > sched_kthread_stop_ret sched_process_free sched_wait_task > sched_migrate_task sched_process_wait sched_wakeup > sched_process_exit sched_signal_send sched_wakeup_new > > # ls /debug/tracing/events/sched_switch/ > enable > > # cat /debug/tracing/events/sched_switch/enable > 1 > > # cat /debug/tracing/set_event > sched_switch
Do you plan to add other things inside these events directory? I mean, if you plan to only put an enable file on each of them, it would be better to have just one file:
cat /debug/tracing/events/sched_switch 1
> Signed-off-by: Steven Rostedt <srostedt@redhat.com> > --- > kernel/trace/trace_events.c | 137 +++++++++++++++++++++++++++++++++++++++++-- > kernel/trace/trace_events.h | 7 ++- > 2 files changed, 137 insertions(+), 7 deletions(-) > > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index 05bc80e..3bcb9df 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -12,6 +12,11 @@ > > #include "trace_events.h" > > +#define events_for_each(event) \ > + for (event = __start_ftrace_events; \ > + (unsigned long)event < (unsigned long)__stop_ftrace_events; \ > + event++) > +
The name for_each_events seems to me more intuitive, but it's just a matter of taste.
Frederic.
> void event_trace_printk(unsigned long ip, const char *fmt, ...) > { > va_list ap; > @@ -39,15 +44,16 @@ static void ftrace_clear_events(void) > > static int ftrace_set_clr_event(char *buf, int set) > { > - struct ftrace_event_call *call = (void *)__start_ftrace_events; > + struct ftrace_event_call *call = __start_ftrace_events; > > > - while ((unsigned long)call < (unsigned long)__stop_ftrace_events) { > + events_for_each(call) { > > - if (strcmp(buf, call->name) != 0) { > - call++; > + if (!call->name) > + continue; > + > + if (strcmp(buf, call->name) != 0) > continue; > - } > > if (set) { > /* Already set? */ > @@ -223,6 +229,67 @@ ftrace_event_seq_open(struct inode *inode, struct file *file) > return ret; > } > > +static ssize_t > +event_enable_read(struct file *filp, char __user *ubuf, size_t cnt, > + loff_t *ppos) > +{ > + struct ftrace_event_call *call = filp->private_data; > + char *buf; > + > + if (call->enabled) > + buf = "1\n"; > + else > + buf = "0\n"; > + > + return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2); > +} > + > +static ssize_t > +event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, > + loff_t *ppos) > +{ > + struct ftrace_event_call *call = filp->private_data; > + char buf[64]; > + unsigned long val; > + int ret; > + > + if (cnt >= sizeof(buf)) > + return -EINVAL; > + > + if (copy_from_user(&buf, ubuf, cnt)) > + return -EFAULT; > + > + buf[cnt] = 0; > + > + ret = strict_strtoul(buf, 10, &val); > + if (ret < 0) > + return ret; > + > + switch (val) { > + case 0: > + if (!call->enabled) > + break; > + > + call->enabled = 0; > + call->unregfunc(); > + break; > + case 1: > + if (call->enabled) > + break; > + > + call->enabled = 1; > + call->regfunc(); > + break; > + > + default: > + return -EINVAL; > + } > + > + *ppos += cnt; > + > + return cnt; > +} > + > static const struct seq_operations show_event_seq_ops = { > .start = t_start, > .next = t_next, > @@ -252,10 +319,59 @@ static const struct file_operations ftrace_set_event_fops = { > .release = seq_release, > }; > > +static const struct file_operations ftrace_enable_fops = { > + .open = tracing_open_generic, > + .read = event_enable_read, > + .write = event_enable_write, > +}; > + > +static struct dentry *event_trace_events_dir(void) > +{ > + static struct dentry *d_tracer; > + static struct dentry *d_events; > + > + if (d_events) > + return d_events; > + > + d_tracer = tracing_init_dentry(); > + if (!d_tracer) > + return NULL; > + > + d_events = debugfs_create_dir("events", d_tracer); > + if (!d_events) > + pr_warning("Could not create debugfs " > + "'events' directory\n"); > + > + return d_events; > +} > + > +static int > +event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) > +{ > + struct dentry *entry; > + > + call->dir = debugfs_create_dir(call->name, d_events); > + if (!call->dir) { > + pr_warning("Could not create debugfs " > + "'%s' directory\n", call->name); > + return -1; > + } > + > + entry = debugfs_create_file("enable", 0644, call->dir, call, > + &ftrace_enable_fops); > + if (!entry) > + pr_warning("Could not create debugfs " > + "'%s/enable' entry\n", call->name); > + > + return 0; > +} > + > static __init int event_trace_init(void) > { > + struct ftrace_event_call *call = __start_ftrace_events; > struct dentry *d_tracer; > struct dentry *entry; > + struct dentry *d_events; > > d_tracer = tracing_init_dentry(); > if (!d_tracer) > @@ -275,6 +391,17 @@ static __init int event_trace_init(void) > pr_warning("Could not create debugfs " > "'set_event' entry\n"); > > + d_events = event_trace_events_dir(); > + if (!d_events) > + return 0; > + > + events_for_each(call) { > + /* The linker may leave blanks */ > + if (!call->name) > + continue; > + event_create_dir(call, d_events); > + } > + > return 0; > } > fs_initcall(event_trace_init); > diff --git a/kernel/trace/trace_events.h b/kernel/trace/trace_events.h > index 39342f8..cb8455b 100644 > --- a/kernel/trace/trace_events.h > +++ b/kernel/trace/trace_events.h > @@ -1,11 +1,13 @@ > #ifndef _LINUX_KERNEL_TRACE_EVENTS_H > #define _LINUX_KERNEL_TRACE_EVENTS_H > > +#include <linux/debugfs.h> > #include <linux/ftrace.h> > #include "trace.h" > > struct ftrace_event_call { > char *name; > + struct dentry *dir; > int enabled; > int (*regfunc)(void); > void (*unregfunc)(void); > @@ -39,6 +41,7 @@ static void ftrace_unreg_event_##call(void) \ > } \ > \ > static struct ftrace_event_call __used \ > +__attribute__((__aligned__(4))) \ > __attribute__((section("_ftrace_events"))) event_##call = { \ > .name = #call, \ > .regfunc = ftrace_reg_event_##call, \ > @@ -46,7 +49,7 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ > } > > void event_trace_printk(unsigned long ip, const char *fmt, ...); > -extern unsigned long __start_ftrace_events[]; > -extern unsigned long __stop_ftrace_events[]; > +extern struct ftrace_event_call __start_ftrace_events[]; > +extern struct ftrace_event_call __stop_ftrace_events[]; > > #endif /* _LINUX_KERNEL_TRACE_EVENTS_H */ > -- > 1.5.6.5 > > --
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