Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760713Ab3GSPLm (ORCPT ); Fri, 19 Jul 2013 11:11:42 -0400 Received: from mga14.intel.com ([143.182.124.37]:58798 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752310Ab3GSPJq (ORCPT ); Fri, 19 Jul 2013 11:09:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.89,702,1367996400"; d="scan'208";a="367963914" From: Tom Zanussi To: rostedt@goodmis.org Cc: masami.hiramatsu.pt@hitachi.com, jovi.zhangwei@huawei.com, linux-kernel@vger.kernel.org, Tom Zanussi Subject: [PATCH v3 3/9] tracing: add 'traceon' and 'traceoff' event trigger commands Date: Fri, 19 Jul 2013 10:09:30 -0500 Message-Id: X-Mailer: git-send-email 1.7.11.4 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 9458 Lines: 380 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. Signed-off-by: Tom Zanussi --- 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; } -- 1.7.11.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/