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tracing: Add hist trigger 'execname' modifier

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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>
This commit is contained in:
Tom Zanussi 2016-03-03 12:54:50 -06:00 committed by Steven Rostedt
parent c6afad49d1
commit 6b4827ad02
2 changed files with 101 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
kernel/trace/trace.c
View File

@ -3857,7 +3857,8 @@ static const char readme_msg[] =
"\t following modifiers to the field name, as applicable:\n\n"
"\t .hex display a number as a hex value\n"
"\t .sym display an address as a symbol\n"
"\t .sym-offset display an address as a symbol and offset\n\n"
"\t .sym-offset display an address as a symbol and offset\n"
"\t .execname display a common_pid as a program name\n\n"
"\t The 'pause' parameter can be used to pause an existing hist\n"
"\t trigger or to start a hist trigger but not log any events\n"
"\t until told to do so. 'continue' can be used to start or\n"

100
kernel/trace/trace_events_hist.c
View File

@ -83,6 +83,7 @@ enum hist_field_flags {
HIST_FIELD_FL_HEX = 8,
HIST_FIELD_FL_SYM = 16,
HIST_FIELD_FL_SYM_OFFSET = 32,
HIST_FIELD_FL_EXECNAME = 64,
};
struct hist_trigger_attrs {
@ -232,6 +233,73 @@ static struct hist_trigger_attrs *parse_hist_trigger_attrs(char *trigger_str)
return ERR_PTR(ret);
}
static inline void save_comm(char *comm, struct task_struct *task)
{
if (!task->pid) {
strcpy(comm, "<idle>");
return;
}
if (WARN_ON_ONCE(task->pid < 0)) {
strcpy(comm, "<XXX>");
return;
}
memcpy(comm, task->comm, TASK_COMM_LEN);
}
static void hist_trigger_elt_comm_free(struct tracing_map_elt *elt)
{
kfree((char *)elt->private_data);
}
static int hist_trigger_elt_comm_alloc(struct tracing_map_elt *elt)
{
struct hist_trigger_data *hist_data = elt->map->private_data;
struct hist_field *key_field;
unsigned int i;
for_each_hist_key_field(i, hist_data) {
key_field = hist_data->fields[i];
if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
unsigned int size = TASK_COMM_LEN + 1;
elt->private_data = kzalloc(size, GFP_KERNEL);
if (!elt->private_data)
return -ENOMEM;
break;
}
}
return 0;
}
static void hist_trigger_elt_comm_copy(struct tracing_map_elt *to,
struct tracing_map_elt *from)
{
char *comm_from = from->private_data;
char *comm_to = to->private_data;
if (comm_from)
memcpy(comm_to, comm_from, TASK_COMM_LEN + 1);
}
static void hist_trigger_elt_comm_init(struct tracing_map_elt *elt)
{
char *comm = elt->private_data;
if (comm)
save_comm(comm, current);
}
static const struct tracing_map_ops hist_trigger_elt_comm_ops = {
.elt_alloc = hist_trigger_elt_comm_alloc,
.elt_copy = hist_trigger_elt_comm_copy,
.elt_free = hist_trigger_elt_comm_free,
.elt_init = hist_trigger_elt_comm_init,
};
static void destroy_hist_field(struct hist_field *hist_field)
{
kfree(hist_field);
@ -403,6 +471,9 @@ static int create_key_field(struct hist_trigger_data *hist_data,
flags |= HIST_FIELD_FL_SYM;
else if (strcmp(field_str, "sym-offset") == 0)
flags |= HIST_FIELD_FL_SYM_OFFSET;
else if ((strcmp(field_str, "execname") == 0) &&
(strcmp(field_name, "common_pid") == 0))
flags |= HIST_FIELD_FL_EXECNAME;
else {
ret = -EINVAL;
goto out;
@ -624,11 +695,27 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
return 0;
}
static bool need_tracing_map_ops(struct hist_trigger_data *hist_data)
{
struct hist_field *key_field;
unsigned int i;
for_each_hist_key_field(i, hist_data) {
key_field = hist_data->fields[i];
if (key_field->flags & HIST_FIELD_FL_EXECNAME)
return true;
}
return false;
}
static struct hist_trigger_data *
create_hist_data(unsigned int map_bits,
struct hist_trigger_attrs *attrs,
struct trace_event_file *file)
{
const struct tracing_map_ops *map_ops = NULL;
struct hist_trigger_data *hist_data;
int ret = 0;
@ -646,8 +733,11 @@ create_hist_data(unsigned int map_bits,
if (ret)
goto free;
if (need_tracing_map_ops(hist_data))
map_ops = &hist_trigger_elt_comm_ops;
hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
NULL, hist_data);
map_ops, hist_data);
if (IS_ERR(hist_data->map)) {
ret = PTR_ERR(hist_data->map);
hist_data->map = NULL;
@ -758,6 +848,12 @@ hist_trigger_entry_print(struct seq_file *m,
sprint_symbol(str, uval);
seq_printf(m, "%s: [%llx] %-55s",
key_field->field->name, uval, str);
} else if (key_field->flags & HIST_FIELD_FL_EXECNAME) {
char *comm = elt->private_data;
uval = *(u64 *)(key + key_field->offset);
seq_printf(m, "%s: %-16s[%10llu]",
key_field->field->name, comm, uval);
} else if (key_field->flags & HIST_FIELD_FL_STRING) {
seq_printf(m, "%s: %-50s", key_field->field->name,
(char *)(key + key_field->offset));
@ -877,6 +973,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
flags_str = "sym";
else if (hist_field->flags & HIST_FIELD_FL_SYM_OFFSET)
flags_str = "sym-offset";
else if (hist_field->flags & HIST_FIELD_FL_EXECNAME)
flags_str = "execname";
return flags_str;
}