[PATCH 4/6] tracing: Use trace event error_log with hist triggers

Tom Zanussi
2018-04-12T15:13:47Z

Replace hist_err() and hist_err_event() with event_log_err() from the
new trace event error_log mechanism.

Also add a couple related helper functions and remove most of the old
hist_err()-related code.

With this change, users no longer read the hist files for hist trigger
error information, but instead look at the tracing/events/error_log
for the same information.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
kernel/trace/trace_events_hist.c | 161 ++++++++++++++++-----------------------
1 file changed, 66 insertions(+), 95 deletions(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 4a42df4..08424ff 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -355,7 +355,26 @@ struct action_data {

static char last_hist_cmd[MAX_FILTER_STR_VAL];
static char last_hist_cmd_event[MAX_FILTER_STR_VAL];
-static char hist_err_str[MAX_FILTER_STR_VAL];
+
+#define log_err(fmt, ...) \
+ event_log_err(last_hist_cmd_event, last_hist_cmd, fmt, ##__VA_ARGS__)
+
+static char *fqvar(char *system, char *event_name, char *var_name, bool ref)
+{
+ static char fqvar[MAX_FILTER_STR_VAL];
+ char *fmt = ref ? "%s.%s.$%s" : "%s.%s.%s";
+
+ if (system && event_name && var_name) {
+ fmt = ref ? "%s.%s.$%s" : "%s.%s.%s";
+ snprintf(fqvar, MAX_FILTER_STR_VAL, fmt, system, event_name);
+ } else if (var_name) {
+ fmt = ref ? "$%s" : "%s";
+ snprintf(fqvar, MAX_FILTER_STR_VAL, fmt, var_name);
+ } else
+ return NULL;
+
+ return fqvar;
+}

static void last_cmd_set(struct trace_event_file *file, char *str)
{
@@ -382,55 +401,12 @@ static void last_cmd_set(struct trace_event_file *file, char *str)
snprintf(last_hist_cmd_event, MAX_FILTER_STR_VAL, "%s:%s", system, name);
}

-static void hist_err(char *str, char *var)
-{
- int maxlen = MAX_FILTER_STR_VAL - 1;
-
- if (!str)
- return;
-
- if (strlen(hist_err_str))
- return;
-
- if (!var)
- var = "";
-
- if (strlen(hist_err_str) + strlen(str) + strlen(var) > maxlen)
- return;
-
- strcat(hist_err_str, str);
- strcat(hist_err_str, var);
-}
-
-static void hist_err_event(char *str, char *system, char *event, char *var)
-{
- char err[MAX_FILTER_STR_VAL];
-
- if (system && var)
- snprintf(err, MAX_FILTER_STR_VAL, "%s.%s.%s", system, event, var);
- else if (system)
- snprintf(err, MAX_FILTER_STR_VAL, "%s.%s", system, event);
- else
- strncpy(err, var, MAX_FILTER_STR_VAL);
-
- hist_err(str, err);
-}
-
static void hist_err_clear(void)
{
- hist_err_str[0] = '\0';
last_hist_cmd[0] = '\0';
last_hist_cmd_event[0] = '\0';
}

-static bool have_hist_err(void)
-{
- if (strlen(hist_err_str))
- return true;
-
- return false;
-}
-
static LIST_HEAD(synth_event_list);
static DEFINE_MUTEX(synth_event_mutex);

@@ -1539,7 +1515,7 @@ static struct trace_event_file *find_var_file(struct trace_array *tr,

if (find_var_field(var_hist_data, var_name)) {
if (found) {
- hist_err_event("Variable name not unique, need to use fully qualified name (subsys.event.var) for variable: ", system, event_name, var_name);
+ log_err("Variable name not unique, need to use fully qualified name (%s) for variable: ", fqvar(system, event_name, var_name, true));
return NULL;
}

@@ -1590,7 +1566,7 @@ static struct hist_field *find_file_var(struct trace_event_file *file,
hist_field = find_file_var(file, var_name);
if (hist_field) {
if (found) {
- hist_err_event("Variable name not unique, need to use fully qualified name (subsys.event.var) for variable: ", system, event_name, var_name);
+ log_err("Variable name not unique, need to use fully qualified name (%s) for variable: ", fqvar(system, event_name, var_name, true));
return ERR_PTR(-EINVAL);
}

@@ -1887,7 +1863,7 @@ static int parse_assignment(char *str, struct hist_trigger_attrs *attrs)
char *assignment;

if (attrs->n_assignments == TRACING_MAP_VARS_MAX) {
- hist_err("Too many variables defined: ", str);
+ log_err("Too many variables defined: %s", str);
ret = -EINVAL;
goto out;
}
@@ -2451,8 +2427,7 @@ static struct hist_field *parse_var_ref(struct hist_trigger_data *hist_data,
ref_field = create_var_ref(var_field, system, event_name);

if (!ref_field)
- hist_err_event("Couldn't find variable: $",
- system, event_name, var_name);
+ log_err("Couldn't find variable: %s", fqvar(system, event_name, var_name, true));

return ref_field;
}
@@ -2613,7 +2588,7 @@ static struct hist_field *parse_unary(struct hist_trigger_data *hist_data,
/* we support only -(xxx) i.e. explicit parens required */

if (level > 3) {
- hist_err("Too many subexpressions (3 max): ", str);
+ log_err("Too many subexpressions (3 max): %s", str);
ret = -EINVAL;
goto free;
}
@@ -2696,7 +2671,7 @@ static int check_expr_operands(struct hist_field *operand1,

if ((operand1_flags & HIST_FIELD_FL_TIMESTAMP_USECS) !=
(operand2_flags & HIST_FIELD_FL_TIMESTAMP_USECS)) {
- hist_err("Timestamp units in expression don't match", NULL);
+ log_err("Timestamp units in expression don't match");
return -EINVAL;
}

@@ -2714,7 +2689,7 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data,
char *sep, *operand1_str;

if (level > 3) {
- hist_err("Too many subexpressions (3 max): ", str);
+ log_err("Too many subexpressions (3 max): %s", str);
return ERR_PTR(-EINVAL);
}

@@ -2952,16 +2927,16 @@ static struct trace_event_file *event_file(struct trace_array *tr,
int ret;

if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) {
- hist_err_event("onmatch: Too many field variables defined: ",
- subsys_name, event_name, field_name);
+ log_err("onmatch: Too many field variables defined: %s",
+ fqvar(subsys_name, event_name, field_name, false));
return ERR_PTR(-EINVAL);
}

file = event_file(tr, subsys_name, event_name);

if (IS_ERR(file)) {
- hist_err_event("onmatch: Event file not found: ",
- subsys_name, event_name, field_name);
+ log_err("onmatch: Event file not found: %s",
+ fqvar(subsys_name, event_name, field_name, false));
ret = PTR_ERR(file);
return ERR_PTR(ret);
}
@@ -2974,8 +2949,8 @@ static struct trace_event_file *event_file(struct trace_array *tr,
*/
hist_data = find_compatible_hist(target_hist_data, file);
if (!hist_data) {
- hist_err_event("onmatch: Matching event histogram not found: ",
- subsys_name, event_name, field_name);
+ log_err("onmatch: Matching event histogram not found: %s",
+ fqvar(subsys_name, event_name, field_name, false));
return ERR_PTR(-EINVAL);
}

@@ -3036,8 +3011,8 @@ static struct trace_event_file *event_file(struct trace_array *tr,
kfree(cmd);
kfree(var_hist->cmd);
kfree(var_hist);
- hist_err_event("onmatch: Couldn't create histogram for field: ",
- subsys_name, event_name, field_name);
+ log_err("onmatch: Couldn't create histogram for field: %s",
+ fqvar(subsys_name, event_name, field_name, false));
return ERR_PTR(ret);
}

@@ -3049,8 +3024,8 @@ static struct trace_event_file *event_file(struct trace_array *tr,
if (IS_ERR_OR_NULL(event_var)) {
kfree(var_hist->cmd);
kfree(var_hist);
- hist_err_event("onmatch: Couldn't find synthetic variable: ",
- subsys_name, event_name, field_name);
+ log_err("onmatch: Couldn't find synthetic variable: %s",
+ fqvar(subsys_name, event_name, field_name, false));
return ERR_PTR(-EINVAL);
}

@@ -3187,21 +3162,21 @@ static struct field_var *create_field_var(struct hist_trigger_data *hist_data,
int ret = 0;

if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) {
- hist_err("Too many field variables defined: ", field_name);
+ log_err("Too many field variables defined: %s", field_name);
ret = -EINVAL;
goto err;
}

val = parse_atom(hist_data, file, field_name, &flags, NULL);
if (IS_ERR(val)) {
- hist_err("Couldn't parse field variable: ", field_name);
+ log_err("Couldn't parse field variable: %s", field_name);
ret = PTR_ERR(val);
goto err;
}

var = create_var(hist_data, file, field_name, val->size, val->type);
if (IS_ERR(var)) {
- hist_err("Couldn't create or find variable: ", field_name);
+ log_err("Couldn't create or find variable: %s", field_name);
kfree(val);
ret = PTR_ERR(var);
goto err;
@@ -3345,14 +3320,14 @@ static int onmax_create(struct hist_trigger_data *hist_data,

onmax_var_str = data->onmax.var_str;
if (onmax_var_str[0] != '$') {
- hist_err("onmax: For onmax(x), x must be a variable: ", onmax_var_str);
+ log_err("onmax: For onmax(x), x must be a variable: %s", onmax_var_str);
return -EINVAL;
}
onmax_var_str++;

var_field = find_target_event_var(hist_data, NULL, NULL, onmax_var_str);
if (!var_field) {
- hist_err("onmax: Couldn't find onmax variable: ", onmax_var_str);
+ log_err("onmax: Couldn't find onmax variable: %s", onmax_var_str);
return -EINVAL;
}

@@ -3374,7 +3349,7 @@ static int onmax_create(struct hist_trigger_data *hist_data,
data->onmax.max_var_ref_idx = var_ref_idx;
max_var = create_var(hist_data, file, "max", sizeof(u64), "u64");
if (IS_ERR(max_var)) {
- hist_err("onmax: Couldn't create onmax variable: ", "max");
+ log_err("onmax: Couldn't create onmax variable: max");
ret = PTR_ERR(max_var);
goto out;
}
@@ -3389,7 +3364,7 @@ static int onmax_create(struct hist_trigger_data *hist_data,

field_var = create_target_field_var(hist_data, NULL, NULL, param);
if (IS_ERR(field_var)) {
- hist_err("onmax: Couldn't create field variable: ", param);
+ log_err("onmax: Couldn't create field variable: %s", param);
ret = PTR_ERR(field_var);
kfree(param);
goto out;
@@ -3422,7 +3397,7 @@ static int parse_action_params(char *params, struct action_data *data)

param = strstrip(param);
if (strlen(param) < 2) {
- hist_err("Invalid action param: ", param);
+ log_err("Invalid action param: %s", param);
ret = -EINVAL;
goto out;
}
@@ -3599,7 +3574,8 @@ static int check_synth_field(struct synth_event *event,
}

if (!hist_field)
- hist_err_event("onmatch: Couldn't find onmatch param: $", system, event, var);
+ log_err("onmatch: Couldn't find onmatch param: %s",
+ fqvar(system, event, var, true));

return hist_field;
}
@@ -3668,7 +3644,7 @@ static int onmatch_create(struct hist_trigger_data *hist_data,
mutex_lock(&synth_event_mutex);
event = find_synth_event(data->onmatch.synth_event_name);
if (!event) {
- hist_err("onmatch: Couldn't find synthetic event: ", data->onmatch.synth_event_name);
+ log_err("onmatch: Couldn't find synthetic event: %s", data->onmatch.synth_event_name);
mutex_unlock(&synth_event_mutex);
return -EINVAL;
}
@@ -3728,15 +3704,15 @@ static int onmatch_create(struct hist_trigger_data *hist_data,
continue;
}

- hist_err_event("onmatch: Param type doesn't match synthetic event field type: ",
- system, event_name, param);
+ log_err("onmatch: Param type doesn't match synthetic event field type: %s",
+ fqvar(system, event_name, param, false));
kfree(p);
ret = -EINVAL;
goto err;
}

if (field_pos != event->n_fields) {
- hist_err("onmatch: Param count doesn't match synthetic event field count: ", event->name);
+ log_err("onmatch: Param count doesn't match synthetic event field count: %s", event->name);
ret = -EINVAL;
goto err;
}
@@ -3767,19 +3743,19 @@ static struct action_data *onmatch_parse(struct trace_array *tr, char *str)

match_event = strsep(&str, ")");
if (!match_event || !str) {
- hist_err("onmatch: Missing closing paren: ", match_event);
+ log_err("onmatch: Missing closing paren: %s", match_event);
goto free;
}

match_event_system = strsep(&match_event, ".");
if (!match_event) {
- hist_err("onmatch: Missing subsystem for match event: ", match_event_system);
+ log_err("onmatch: Missing subsystem for match event: %s", match_event_system);
goto free;
}

if (IS_ERR(event_file(tr, match_event_system, match_event))) {
- hist_err_event("onmatch: Invalid subsystem or event name: ",
- match_event_system, match_event, NULL);
+ log_err("onmatch: Invalid subsystem or event name: %s.%s",
+ match_event_system, match_event);
goto free;
}

@@ -3797,13 +3773,13 @@ static struct action_data *onmatch_parse(struct trace_array *tr, char *str)

strsep(&str, ".");
if (!str) {
- hist_err("onmatch: Missing . after onmatch(): ", str);
+ log_err("onmatch: Missing . after onmatch(): %s", str);
goto free;
}

synth_event_name = strsep(&str, "(");
if (!synth_event_name || !str) {
- hist_err("onmatch: Missing opening paramlist paren: ", synth_event_name);
+ log_err("onmatch: Missing opening paramlist paren: %s", synth_event_name);
goto free;
}

@@ -3815,7 +3791,7 @@ static struct action_data *onmatch_parse(struct trace_array *tr, char *str)

params = strsep(&str, ")");
if (!params || !str || (str && strlen(str))) {
- hist_err("onmatch: Missing closing paramlist paren: ", params);
+ log_err("onmatch: Missing closing paramlist paren: %s", params);
goto free;
}

@@ -3894,7 +3870,7 @@ static int create_var_field(struct hist_trigger_data *hist_data,
return -EINVAL;

if (find_var(hist_data, file, var_name) && !hist_data->remove) {
- hist_err("Variable already defined: ", var_name);
+ log_err("Variable already defined: %s", var_name);
return -EINVAL;
}

@@ -3975,7 +3951,7 @@ static int create_key_field(struct hist_trigger_data *hist_data,
}

if (hist_field->flags & HIST_FIELD_FL_VAR_REF) {
- hist_err("Using variable references as keys not supported: ", field_str);
+ log_err("Using variable references as keys not supported: %s", field_str);
destroy_hist_field(hist_field, 0);
ret = -EINVAL;
goto out;
@@ -4089,13 +4065,13 @@ static int parse_var_defs(struct hist_trigger_data *hist_data)

var_name = strsep(&field_str, "=");
if (!var_name || !field_str) {
- hist_err("Malformed assignment: ", var_name);
+ log_err("Malformed assignment: %s", var_name);
ret = -EINVAL;
goto free;
}

if (n_vars == TRACING_MAP_VARS_MAX) {
- hist_err("Too many variables defined: ", var_name);
+ log_err("Too many variables defined: %s", var_name);
ret = -EINVAL;
goto free;
}
@@ -4894,11 +4870,6 @@ static int hist_show(struct seq_file *m, void *v)
hist_trigger_show(m, data, n++);
}

- if (have_hist_err()) {
- seq_printf(m, "\nERROR: %s\n", hist_err_str);
- seq_printf(m, " Last command: %s\n", last_hist_cmd);
- }
-
out_unlock:
mutex_unlock(&event_mutex);

@@ -5270,7 +5241,7 @@ static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,
if (named_data) {
if (!hist_trigger_match(data, named_data, named_data,
true)) {
- hist_err("Named hist trigger doesn't match existing named trigger (includes variables): ", hist_data->attrs->name);
+ log_err("Named hist trigger doesn't match existing named trigger (includes variables): %s", hist_data->attrs->name);
ret = -EINVAL;
goto out;
}
@@ -5291,7 +5262,7 @@ static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,
else if (hist_data->attrs->clear)
hist_clear(test);
else {
- hist_err("Hist trigger already exists", NULL);
+ log_err("Hist trigger already exists");
ret = -EEXIST;
}
goto out;
@@ -5299,7 +5270,7 @@ static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,
}
new:
if (hist_data->attrs->cont || hist_data->attrs->clear) {
- hist_err("Can't clear or continue a nonexistent hist trigger", NULL);
+ log_err("Can't clear or continue a nonexistent hist trigger");
ret = -ENOENT;
goto out;
}
@@ -5324,7 +5295,7 @@ static int hist_register_trigger(char *glob, struct event_trigger_ops *ops,

ret = tracing_set_clock(file->tr, hist_data->attrs->clock);
if (ret) {
- hist_err("Couldn't set trace_clock: ", clock);
+ log_err("Couldn't set trace_clock: %s", clock);
goto out;
}

--
1.9.3