Allow users to have pid fields displayed as program names in the output
by appending '.execname' to field names:
# echo hist:keys=aaa.execname ... \
[ if filter] > event/trigger
Signed-off-by: Tom Zanussi <[email protected]>
---
kernel/trace/trace.c | 3 +-
kernel/trace/trace_events_hist.c | 86 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 87 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 12b5907..ac5454e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3811,7 +3811,8 @@ 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 e6e5c6e..656973a 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -75,6 +75,7 @@ enum hist_field_flags {
HIST_FIELD_HEX = 8,
HIST_FIELD_SYM = 16,
HIST_FIELD_SYM_OFFSET = 32,
+ HIST_FIELD_EXECNAME = 64,
};
struct hist_trigger_attrs {
@@ -218,6 +219,78 @@ 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;
+ }
+
+ if (task->pid > PID_MAX_DEFAULT) {
+ strcpy(comm, "<...>");
+ return;
+ }
+
+ memcpy(comm, task->comm, TASK_COMM_LEN);
+}
+
+static void hist_trigger_elt_free(struct tracing_map_elt *elt)
+{
+ kfree((char *)elt->private_data);
+}
+
+static int hist_trigger_elt_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 (i = hist_data->n_vals; i < hist_data->n_fields; i++) {
+ key_field = hist_data->fields[i];
+
+ if (key_field->flags & HIST_FIELD_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_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_init(struct tracing_map_elt *elt)
+{
+ char *comm = elt->private_data;
+
+ if (comm)
+ save_comm(comm, current);
+}
+
+static struct tracing_map_ops hist_trigger_ops = {
+ .elt_alloc = hist_trigger_elt_alloc,
+ .elt_copy = hist_trigger_elt_copy,
+ .elt_free = hist_trigger_elt_free,
+ .elt_init = hist_trigger_elt_init,
+};
+
static void destroy_hist_field(struct hist_field *hist_field)
{
kfree(hist_field);
@@ -376,6 +449,9 @@ static int create_key_field(struct hist_trigger_data
*hist_data,
flags |= HIST_FIELD_SYM;
else if (!strcmp(field_str, "sym-offset"))
flags |= HIST_FIELD_SYM_OFFSET;
+ else if (!strcmp(field_str, "execname") &&
+ !strcmp(field_name, "common_pid"))
+ flags |= HIST_FIELD_EXECNAME;
else {
ret = -EINVAL;
goto out;
@@ -612,7 +688,7 @@ create_hist_data(unsigned int map_bits,
goto free;
hist_data->map = tracing_map_create(map_bits, hist_data->key_size,
- NULL, hist_data);
+ &hist_trigger_ops, hist_data);
if (IS_ERR(hist_data->map)) {
ret = PTR_ERR(hist_data->map);
hist_data->map = NULL;
@@ -732,6 +808,12 @@ 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_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_STRING) {
seq_printf(m, "%s: %-50s", key_field->field->name,
(char *)(key + key_field->offset));
@@ -851,6 +933,8 @@ static const char *get_hist_field_flags(struct hist_field
*hist_field)
flags_str = "sym";
else if (hist_field->flags & HIST_FIELD_SYM_OFFSET)
flags_str = "sym-offset";
+ else if (hist_field->flags & HIST_FIELD_EXECNAME)
+ flags_str = "execname";
return flags_str;
}
--
1.9.3
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