Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932380Ab3ICDxE (ORCPT ); Mon, 2 Sep 2013 23:53:04 -0400 Received: from mga02.intel.com ([134.134.136.20]:12839 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932296Ab3ICDxB (ORCPT ); Mon, 2 Sep 2013 23:53:01 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.89,1011,1367996400"; d="scan'208";a="397305442" From: Tom Zanussi To: rostedt@goodmis.org Cc: masami.hiramatsu.pt@hitachi.com, linux-kernel@vger.kernel.org, Tom Zanussi Subject: [PATCH v8 04/10] tracing: Add 'snapshot' event trigger command Date: Mon, 2 Sep 2013 22:52:20 -0500 Message-Id: <03b1cfe923295a6b804569ee814b3ffbc9623397.1378176577.git.tom.zanussi@linux.intel.com> 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: 5396 Lines: 178 Add 'snapshot' event_command. snapshot event triggers are added by the user via this command in a similar way and using practically the same syntax as the analogous 'snapshot' ftrace function command, but instead of writing to the set_ftrace_filter file, the snapshot event trigger is written to the per-event 'trigger' files: echo 'snapshot' > .../somesys/someevent/trigger The above command will turn on snapshots for someevent i.e. whenever someevent is hit, a snapshot will be done. This also adds a 'count' version that limits the number of times the command will be invoked: echo 'snapshot:N' > .../somesys/someevent/trigger Where N is the number of times the command will be invoked. The above command will snapshot N times for someevent i.e. whenever someevent is hit N times, a snapshot will be done. Also adds a new ftrace_alloc_snapshot() function - the ftrace snapshot command defines code that allocates a snapshot, which would be nice to be able to reuse, which this does. Signed-off-by: Tom Zanussi --- include/linux/ftrace_event.h | 1 + kernel/trace/trace.c | 9 +++++ kernel/trace/trace.h | 1 + kernel/trace/trace_events_trigger.c | 76 +++++++++++++++++++++++++++++++++++++ 4 files changed, 87 insertions(+) diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index a14650b..40b517b 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -319,6 +319,7 @@ struct ftrace_event_file { enum event_trigger_type { ETT_NONE = (0), ETT_TRACE_ONOFF = (1 << 0), + ETT_SNAPSHOT = (1 << 1), }; extern void destroy_preds(struct ftrace_event_call *call); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 496f94d..5a61dbe 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5358,6 +5358,15 @@ static const struct file_operations tracing_dyn_info_fops = { }; #endif /* CONFIG_DYNAMIC_FTRACE */ +#if defined(CONFIG_TRACER_SNAPSHOT) +int ftrace_alloc_snapshot(void) +{ + return alloc_snapshot(&global_trace); +} +#else +int ftrace_alloc_snapshot(void) { return -ENOSYS; } +#endif + #if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) static void ftrace_snapshot(unsigned long ip, unsigned long parent_ip, void **data) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 37b8ecf..f032dd8 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1200,6 +1200,7 @@ struct event_command { extern int trace_event_enable_disable(struct ftrace_event_file *file, int enable, int soft_disable); +extern int ftrace_alloc_snapshot(void); extern const char *__start___trace_bprintk_fmt[]; extern const char *__stop___trace_bprintk_fmt[]; diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 5388d55..9bdcc38 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -664,6 +664,74 @@ static struct event_command trigger_traceoff_cmd = { .get_trigger_ops = onoff_get_trigger_ops, }; +static void +snapshot_trigger(struct event_trigger_data *data) +{ + tracing_snapshot(); +} + +static void +snapshot_count_trigger(struct event_trigger_data *data) +{ + if (!data->count) + return; + + if (data->count != -1) + (data->count)--; + + snapshot_trigger(data); +} + +static int +register_snapshot_trigger(char *glob, struct event_trigger_ops *ops, + struct event_trigger_data *data, + struct ftrace_event_file *file) +{ + int ret = register_trigger(glob, ops, data, file); + + if (ret > 0) + ftrace_alloc_snapshot(); + + return ret; +} + +static int +snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops, + struct event_trigger_data *data) +{ + return event_trigger_print("snapshot", m, (void *)data->count, + data->filter_str); +} + +static struct event_trigger_ops snapshot_trigger_ops = { + .func = snapshot_trigger, + .print = snapshot_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops snapshot_count_trigger_ops = { + .func = snapshot_count_trigger, + .print = snapshot_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops * +snapshot_get_trigger_ops(char *cmd, char *param) +{ + return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops; +} + +static struct event_command trigger_snapshot_cmd = { + .name = "snapshot", + .trigger_type = ETT_SNAPSHOT, + .func = event_trigger_callback, + .reg = register_snapshot_trigger, + .unreg = unregister_trigger, + .get_trigger_ops = snapshot_get_trigger_ops, +}; + static __init void unregister_trigger_traceon_traceoff_cmds(void) { unregister_event_command(&trigger_traceon_cmd, @@ -700,5 +768,13 @@ __init int register_trigger_cmds(void) return ret; } + ret = register_event_command(&trigger_snapshot_cmd, + &trigger_commands, + &trigger_cmd_mutex); + if (WARN_ON(ret < 0)) { + 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/