tracing: Add hist trigger 'execname' modifier
Allow users to have common_pid field values displayed as program names in the output by appending '.execname' to a common_pid field name: # echo hist:keys=common_pid.execname ... \ [ if filter] > event/trigger Link: http://lkml.kernel.org/r/e172e81f10f5b8d1f08450e3763c850f39fbf698.1457029949.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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@ -3857,7 +3857,8 @@ static const char readme_msg[] =
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"\t following modifiers to the field name, as applicable:\n\n"
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"\t .hex display a number as a hex value\n"
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"\t .sym display an address as a symbol\n"
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"\t .sym-offset display an address as a symbol and offset\n\n"
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"\t .sym-offset display an address as a symbol and offset\n"
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"\t .execname display a common_pid as a program name\n\n"
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"\t The 'pause' parameter can be used to pause an existing hist\n"
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"\t trigger or to start a hist trigger but not log any events\n"
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"\t until told to do so. 'continue' can be used to start or\n"
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@ -83,6 +83,7 @@ enum hist_field_flags {
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HIST_FIELD_FL_HEX = 8,
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HIST_FIELD_FL_SYM = 16,
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HIST_FIELD_FL_SYM_OFFSET = 32,
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HIST_FIELD_FL_EXECNAME = 64,
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};
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struct hist_trigger_attrs {
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@ -232,6 +233,73 @@ static struct hist_trigger_attrs *parse_hist_trigger_attrs(char *trigger_str)
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return ERR_PTR(ret);
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}
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static inline void save_comm(char *comm, struct task_struct *task)
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{
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if (!task->pid) {
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strcpy(comm, "<idle>");
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return;
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}
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if (WARN_ON_ONCE(task->pid < 0)) {
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strcpy(comm, "<XXX>");
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return;
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}
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memcpy(comm, task->comm, TASK_COMM_LEN);
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}
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static void hist_trigger_elt_comm_free(struct tracing_map_elt *elt)
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{
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kfree((char *)elt->private_data);
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}
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static int hist_trigger_elt_comm_alloc(struct tracing_map_elt *elt)
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{
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struct hist_trigger_data *hist_data = elt->map->private_data;
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struct hist_field *key_field;
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unsigned int i;
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for_each_hist_key_field(i, hist_data) {
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key_field = hist_data->fields[i];
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if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
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unsigned int size = TASK_COMM_LEN + 1;
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elt->private_data = kzalloc(size, GFP_KERNEL);
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if (!elt->private_data)
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return -ENOMEM;
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break;
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}
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}
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return 0;
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}
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static void hist_trigger_elt_comm_copy(struct tracing_map_elt *to,
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struct tracing_map_elt *from)
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{
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char *comm_from = from->private_data;
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char *comm_to = to->private_data;
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if (comm_from)
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memcpy(comm_to, comm_from, TASK_COMM_LEN + 1);
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}
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static void hist_trigger_elt_comm_init(struct tracing_map_elt *elt)
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{
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char *comm = elt->private_data;
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if (comm)
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save_comm(comm, current);
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}
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static const struct tracing_map_ops hist_trigger_elt_comm_ops = {
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.elt_alloc = hist_trigger_elt_comm_alloc,
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.elt_copy = hist_trigger_elt_comm_copy,
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.elt_free = hist_trigger_elt_comm_free,
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.elt_init = hist_trigger_elt_comm_init,
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};
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static void destroy_hist_field(struct hist_field *hist_field)
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{
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kfree(hist_field);
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@ -403,6 +471,9 @@ static int create_key_field(struct hist_trigger_data *hist_data,
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flags |= HIST_FIELD_FL_SYM;
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else if (strcmp(field_str, "sym-offset") == 0)
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flags |= HIST_FIELD_FL_SYM_OFFSET;
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else if ((strcmp(field_str, "execname") == 0) &&
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(strcmp(field_name, "common_pid") == 0))
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flags |= HIST_FIELD_FL_EXECNAME;
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else {
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ret = -EINVAL;
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goto out;
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@ -624,11 +695,27 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
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return 0;
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}
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static bool need_tracing_map_ops(struct hist_trigger_data *hist_data)
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{
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struct hist_field *key_field;
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unsigned int i;
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for_each_hist_key_field(i, hist_data) {
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key_field = hist_data->fields[i];
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if (key_field->flags & HIST_FIELD_FL_EXECNAME)
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return true;
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}
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return false;
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}
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static struct hist_trigger_data *
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create_hist_data(unsigned int map_bits,
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struct hist_trigger_attrs *attrs,
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struct trace_event_file *file)
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{
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const struct tracing_map_ops *map_ops = NULL;
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struct hist_trigger_data *hist_data;
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int ret = 0;
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@ -646,8 +733,11 @@ create_hist_data(unsigned int map_bits,
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if (ret)
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goto free;
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if (need_tracing_map_ops(hist_data))
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map_ops = &hist_trigger_elt_comm_ops;
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hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
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NULL, hist_data);
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map_ops, hist_data);
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if (IS_ERR(hist_data->map)) {
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ret = PTR_ERR(hist_data->map);
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hist_data->map = NULL;
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@ -758,6 +848,12 @@ hist_trigger_entry_print(struct seq_file *m,
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sprint_symbol(str, uval);
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seq_printf(m, "%s: [%llx] %-55s",
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key_field->field->name, uval, str);
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} else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
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char *comm = elt->private_data;
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uval = *(u64 *)(key + key_field->offset);
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seq_printf(m, "%s: %-16s[%10llu]",
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key_field->field->name, comm, uval);
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} else if (key_field->flags & HIST_FIELD_FL_STRING) {
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seq_printf(m, "%s: %-50s", key_field->field->name,
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(char *)(key + key_field->offset));
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@ -877,6 +973,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
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flags_str = "sym";
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else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
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flags_str = "sym-offset";
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else if (hist_field->flags & HIST_FIELD_FL_EXECNAME)
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flags_str = "execname";
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return flags_str;
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}
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