(2013/07/20 0:09), Tom Zanussi wrote: > Add 'traceon' and 'traceoff' ftrace_func_command commands. traceon > and traceoff event triggers are added by the user via these commands > in a similar way and using practically the same syntax as the > analagous 'traceon' and 'traceoff' ftrace function commands, but > instead of writing to the set_ftrace_filter file, the traceon and > traceoff triggers are written to the per-event 'trigger' files: > > echo 'traceon' > .../tracing/events/somesys/someevent/trigger > echo 'traceoff' > .../tracing/events/somesys/someevent/trigger > > The above command will turn tracing on or off whenever someevent is > hit. > > This also adds a 'count' version that limits the number of times the > command will be invoked: > > echo 'traceon:N' > .../tracing/events/somesys/someevent/trigger > echo 'traceoff:N' > .../tracing/events/somesys/someevent/trigger > > Where N is the number of times the command will be invoked. > > The above commands will will turn tracing on or off whenever someevent > is hit, but only N times. > > The event_trigger_init() and event_trigger_free() are meant to be > common implementations of the event_trigger_ops init() and free() ops. > Most trigger_ops implementations will use these, but some will > override and possibly reuse them.
Please add a comment in the code. (perhaps, a separator comment is enough) event_trigger_callback(), register_trigger and unregister_trigger in 2/9 are common for event_command func(), reg() and unreg() too. I think it is better to move those common code in this or previous patch. Thank you, > Signed-off-by: Tom Zanussi <[email protected]> > --- > include/linux/ftrace_event.h | 1 + > kernel/trace/trace_events_trigger.c | 313 > ++++++++++++++++++++++++++++++++++++ > 2 files changed, 314 insertions(+) > > diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h > index 6cd5bbc..c794686 100644 > --- a/include/linux/ftrace_event.h > +++ b/include/linux/ftrace_event.h > @@ -316,6 +316,7 @@ struct ftrace_event_file { > > enum trigger_mode { > TM_NONE = (0), > + TM_TRACE_ONOFF = (1 << 0), > }; > > extern void destroy_preds(struct ftrace_event_call *call); > diff --git a/kernel/trace/trace_events_trigger.c > b/kernel/trace/trace_events_trigger.c > index 1f0565c..f2b97b6 100644 > --- a/kernel/trace/trace_events_trigger.c > +++ b/kernel/trace/trace_events_trigger.c > @@ -355,7 +355,320 @@ static void unregister_trigger(char *glob, struct > event_trigger_ops *ops, > data->ops->free(data->ops, (void **)&data); > } > > +int > +event_trigger_print(const char *name, struct seq_file *m, > + void *data, char *filter_str) > +{ > + long count = (long)data; > + > + seq_printf(m, "%s", name); > + > + if (count == -1) > + seq_puts(m, ":unlimited"); > + else > + seq_printf(m, ":count=%ld", count); > + > + if (filter_str) > + seq_printf(m, " if %s\n", filter_str); > + else > + seq_puts(m, "\n"); > + > + return 0; > +} > + > +static int > +event_trigger_init(struct event_trigger_ops *ops, void **_data) > +{ > + struct event_trigger_data **p = (struct event_trigger_data **)_data; > + struct event_trigger_data *data = *p; > + > + data->ref++; > + return 0; > +} > + > +static void > +event_trigger_free(struct event_trigger_ops *ops, void **_data) > +{ > + struct event_trigger_data **p = (struct event_trigger_data **)_data; > + struct event_trigger_data *data = *p; > + > + if (WARN_ON_ONCE(data->ref <= 0)) > + return; > + > + data->ref--; > + if (!data->ref) > + kfree(data); > +} > + > +static int > +event_trigger_callback(struct event_command *cmd_ops, void *cmd_data, > + char *glob, char *cmd, char *param, int enabled) > +{ > + struct event_trigger_ops *trigger_ops; > + struct event_trigger_data *trigger_data; > + char *trigger = NULL; > + char *number; > + int ret; > + > + if (!enabled) > + return -EINVAL; > + > + /* separate the trigger from the filter (t:n [if filter]) */ > + if (param && isdigit(param[0])) > + trigger = strsep(¶m, " \t"); > + > + mutex_lock(&event_mutex); > + > + trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger); > + > + ret = -ENOMEM; > + trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL); > + if (!trigger_data) > + goto out; > + > + trigger_data->count = -1; > + trigger_data->ops = trigger_ops; > + trigger_data->mode = cmd_ops->trigger_mode; > + INIT_LIST_HEAD(&trigger_data->list); > + > + if (glob[0] == '!') { > + cmd_ops->unreg(glob+1, trigger_ops, trigger_data, cmd_data); > + kfree(trigger_data); > + ret = 0; > + goto out; > + } > + > + if (trigger) { > + number = strsep(&trigger, ":"); > + > + ret = -EINVAL; > + if (!strlen(number)) > + goto out_free; > + > + /* > + * We use the callback data field (which is a pointer) > + * as our counter. > + */ > + ret = kstrtoul(number, 0, &trigger_data->count); > + if (ret) > + goto out_free; > + } > + > + if (!param) /* if param is non-empty, it's supposed to be a filter */ > + goto out_reg; > + > + if (!cmd_ops->set_filter) > + goto out_reg; > + > + ret = cmd_ops->set_filter(param, trigger_data, cmd_data); > + if (ret < 0) > + goto out_free; > + > + out_reg: > + ret = cmd_ops->reg(glob, trigger_ops, trigger_data, cmd_data); > + /* > + * The above returns on success the # of functions enabled, > + * but if it didn't find any functions it returns zero. > + * Consider no functions a failure too. > + */ > + if (!ret) { > + ret = -ENOENT; > + goto out_free; > + } else if (ret < 0) > + goto out_free; > + ret = 0; > + out: > + mutex_unlock(&event_mutex); > + return ret; > + > + out_free: > + kfree(trigger_data); > + goto out; > +} > + > +static void > +traceon_trigger(void **_data) > +{ > + struct event_trigger_data **p = (struct event_trigger_data **)_data; > + struct event_trigger_data *data = *p; > + > + if (!data) > + return; > + > + if (tracing_is_on()) > + return; > + > + tracing_on(); > +} > + > +static void > +traceon_count_trigger(void **_data) > +{ > + struct event_trigger_data **p = (struct event_trigger_data **)_data; > + struct event_trigger_data *data = *p; > + > + if (!data) > + return; > + > + if (!data->count) > + return; > + > + if (data->count != -1) > + (data->count)--; > + > + traceon_trigger(_data); > +} > + > +static void > +traceoff_trigger(void **_data) > +{ > + struct event_trigger_data **p = (struct event_trigger_data **)_data; > + struct event_trigger_data *data = *p; > + > + if (!data) > + return; > + > + if (!tracing_is_on()) > + return; > + > + tracing_off(); > +} > + > +static void > +traceoff_count_trigger(void **_data) > +{ > + struct event_trigger_data **p = (struct event_trigger_data **)_data; > + struct event_trigger_data *data = *p; > + > + if (!data) > + return; > + > + if (!data->count) > + return; > + > + if (data->count != -1) > + (data->count)--; > + > + traceoff_trigger(_data); > +} > + > +static int > +traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops, > + void *_data) > +{ > + struct event_trigger_data *data = _data; > + > + return event_trigger_print("traceon", m, (void *)data->count, > + data->filter_str); > +} > + > +static int > +traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops, > + void *_data) > +{ > + struct event_trigger_data *data = _data; > + > + return event_trigger_print("traceoff", m, (void *)data->count, > + data->filter_str); > +} > + > +static struct event_trigger_ops traceon_trigger_ops = { > + .func = traceon_trigger, > + .print = traceon_trigger_print, > + .init = event_trigger_init, > + .free = event_trigger_free, > +}; > + > +static struct event_trigger_ops traceon_count_trigger_ops = { > + .func = traceon_count_trigger, > + .print = traceon_trigger_print, > + .init = event_trigger_init, > + .free = event_trigger_free, > +}; > + > +static struct event_trigger_ops traceoff_trigger_ops = { > + .func = traceoff_trigger, > + .print = traceoff_trigger_print, > + .init = event_trigger_init, > + .free = event_trigger_free, > +}; > + > +static struct event_trigger_ops traceoff_count_trigger_ops = { > + .func = traceoff_count_trigger, > + .print = traceoff_trigger_print, > + .init = event_trigger_init, > + .free = event_trigger_free, > +}; > + > +static struct event_trigger_ops * > +onoff_get_trigger_ops(char *cmd, char *param) > +{ > + struct event_trigger_ops *ops; > + > + /* we register both traceon and traceoff to this callback */ > + if (strcmp(cmd, "traceon") == 0) > + ops = param ? &traceon_count_trigger_ops : > + &traceon_trigger_ops; > + else > + ops = param ? &traceoff_count_trigger_ops : > + &traceoff_trigger_ops; > + > + return ops; > +} > + > +static struct event_command trigger_traceon_cmd = { > + .name = "traceon", > + .trigger_mode = TM_TRACE_ONOFF, > + .func = event_trigger_callback, > + .reg = register_trigger, > + .unreg = unregister_trigger, > + .get_trigger_ops = onoff_get_trigger_ops, > +}; > + > +static struct event_command trigger_traceoff_cmd = { > + .name = "traceoff", > + .trigger_mode = TM_TRACE_ONOFF, > + .func = event_trigger_callback, > + .reg = register_trigger, > + .unreg = unregister_trigger, > + .get_trigger_ops = onoff_get_trigger_ops, > +}; > + > +static __init void unregister_trigger_traceon_traceoff_cmds(void) > +{ > + unregister_event_command(&trigger_traceon_cmd, > + &trigger_commands, > + &trigger_cmd_mutex); > + unregister_event_command(&trigger_traceoff_cmd, > + &trigger_commands, > + &trigger_cmd_mutex); > +} > + > +static __init int register_trigger_traceon_traceoff_cmds(void) > +{ > + int ret; > + > + ret = register_event_command(&trigger_traceon_cmd, &trigger_commands, > + &trigger_cmd_mutex); > + if (WARN_ON(ret < 0)) > + return ret; > + ret = register_event_command(&trigger_traceoff_cmd, &trigger_commands, > + &trigger_cmd_mutex); > + if (WARN_ON(ret < 0)) > + unregister_trigger_traceon_traceoff_cmds(); > + > + return ret; > +} > + > __init int register_trigger_cmds(void) > { > + int ret; > + > + ret = register_trigger_traceon_traceoff_cmds(); > + if (ret) { > + unregister_trigger_traceon_traceoff_cmds(); > + return ret; > + } > + > return 0; > } > -- Masami HIRAMATSU IT Management Research Dept. 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