From 93e31ffbf417a84fbae518fb46b3ea3f0d8fa6e1 Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 24 Oct 2013 08:59:26 -0500 Subject: tracing: Add 'snapshot' event trigger command 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 tracing_alloc_snapshot() function - the existing tracing_snapshot_alloc() function is a special version of tracing_snapshot() that also does the snapshot allocation - the snapshot triggers would like to be able to do just the allocation but not take a snapshot; the existing tracing_snapshot_alloc() in turn now also calls tracing_alloc_snapshot() underneath to do that allocation. Link: http://lkml.kernel.org/r/c9524dd07ce01f9dcbd59011290e0a8d5b47d7ad.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi [ fix up from kbuild test robot --- kernel/trace/trace_events_trigger.c | 85 +++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) (limited to 'kernel/trace/trace_events_trigger.c') diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 4ea72ee169a7..d775c3da180f 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -696,6 +696,90 @@ static struct event_command trigger_traceoff_cmd = { .get_trigger_ops = onoff_get_trigger_ops, }; +#ifdef CONFIG_TRACER_SNAPSHOT +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 && tracing_alloc_snapshot() != 0) { + unregister_trigger(glob, ops, data, file); + ret = 0; + } + + 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 int register_trigger_snapshot_cmd(void) +{ + int ret; + + ret = register_event_command(&trigger_snapshot_cmd); + WARN_ON(ret < 0); + + return ret; +} +#else +static __init int register_trigger_snapshot_cmd(void) { return 0; } +#endif /* CONFIG_TRACER_SNAPSHOT */ + static __init void unregister_trigger_traceon_traceoff_cmds(void) { unregister_event_command(&trigger_traceon_cmd); @@ -719,6 +803,7 @@ static __init int register_trigger_traceon_traceoff_cmds(void) __init int register_trigger_cmds(void) { register_trigger_traceon_traceoff_cmds(); + register_trigger_snapshot_cmd(); return 0; } -- cgit v1.2.3