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authorTom Zanussi <tom.zanussi@linux.intel.com>2016-03-03 12:54:50 -0600
committerSteven Rostedt <rostedt@goodmis.org>2016-04-19 12:17:56 -0400
commit6b4827ad028a1ab2fc4dcf1f5e6e077018d1b770 (patch)
tree08aee91c12713448f419795c09df2d3c2260c9a6 /kernel/trace
parentc6afad49d127f6d7c9957319f55173a2198b1ba8 (diff)
downloadlinux-sh-6b4827ad028a1ab2fc4dcf1f5e6e077018d1b770.tar.gz
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>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c3
-rw-r--r--kernel/trace/trace_events_hist.c100
2 files changed, 101 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 34459eb0c844..58a8bee50c6e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -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"
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 808cc06cdb61..227e6c21b1eb 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -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;
}