Commit 30350d65 authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt (VMware)

tracing: Add variable support to hist triggers

Add support for saving the value of a current event's event field by
assigning it to a variable that can be read by a subsequent event.

The basic syntax for saving a variable is to simply prefix a unique
variable name not corresponding to any keyword along with an '=' sign
to any event field.

Both keys and values can be saved and retrieved in this way:

    # echo 'hist:keys=next_pid:vals=$ts0:ts0=common_timestamp ...
    # echo 'hist:timer_pid=common_pid:key=$timer_pid ...'

If a variable isn't a key variable or prefixed with 'vals=', the
associated event field will be saved in a variable but won't be summed
as a value:

    # echo 'hist:keys=next_pid:ts1=common_timestamp:...

Multiple variables can be assigned at the same time:

    # echo 'hist:keys=pid:vals=$ts0,$b,field2:ts0=common_timestamp,b=field1 ...

Multiple (or single) variables can also be assigned at the same time
using separate assignments:

    # echo 'hist:keys=pid:vals=$ts0:ts0=common_timestamp:b=field1:c=field2 ...

Variables set as above can be used by being referenced from another
event, as described in a subsequent patch.

Link: http://lkml.kernel.org/r/fc93c4944d9719dbcb1d0067be627d44e98e2adc.1516069914.git.tom.zanussi@linux.intel.comSigned-off-by: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: default avatarBaohong Liu <baohong.liu@intel.com>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 860f9f6b
......@@ -30,6 +30,13 @@ typedef u64 (*hist_field_fn_t) (struct hist_field *field, void *event,
struct ring_buffer_event *rbe);
#define HIST_FIELD_OPERANDS_MAX 2
#define HIST_FIELDS_MAX (TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
struct hist_var {
char *name;
struct hist_trigger_data *hist_data;
unsigned int idx;
};
struct hist_field {
struct ftrace_event_field *field;
......@@ -40,6 +47,7 @@ struct hist_field {
unsigned int is_signed;
struct hist_field *operands[HIST_FIELD_OPERANDS_MAX];
struct hist_trigger_data *hist_data;
struct hist_var var;
};
static u64 hist_field_none(struct hist_field *field, void *event,
......@@ -138,6 +146,13 @@ enum hist_field_flags {
HIST_FIELD_FL_LOG2 = 1 << 9,
HIST_FIELD_FL_TIMESTAMP = 1 << 10,
HIST_FIELD_FL_TIMESTAMP_USECS = 1 << 11,
HIST_FIELD_FL_VAR = 1 << 12,
};
struct var_defs {
unsigned int n_vars;
char *name[TRACING_MAP_VARS_MAX];
char *expr[TRACING_MAP_VARS_MAX];
};
struct hist_trigger_attrs {
......@@ -150,13 +165,19 @@ struct hist_trigger_attrs {
bool clear;
bool ts_in_usecs;
unsigned int map_bits;
char *assignment_str[TRACING_MAP_VARS_MAX];
unsigned int n_assignments;
struct var_defs var_defs;
};
struct hist_trigger_data {
struct hist_field *fields[TRACING_MAP_FIELDS_MAX];
struct hist_field *fields[HIST_FIELDS_MAX];
unsigned int n_vals;
unsigned int n_keys;
unsigned int n_fields;
unsigned int n_vars;
unsigned int key_size;
struct tracing_map_sort_key sort_keys[TRACING_MAP_SORT_KEYS_MAX];
unsigned int n_sort_keys;
......@@ -164,6 +185,7 @@ struct hist_trigger_data {
struct hist_trigger_attrs *attrs;
struct tracing_map *map;
bool enable_timestamps;
bool remove;
};
static u64 hist_field_timestamp(struct hist_field *hist_field, void *event,
......@@ -180,6 +202,48 @@ static u64 hist_field_timestamp(struct hist_field *hist_field, void *event,
return ts;
}
static struct hist_field *find_var_field(struct hist_trigger_data *hist_data,
const char *var_name)
{
struct hist_field *hist_field, *found = NULL;
int i;
for_each_hist_field(i, hist_data) {
hist_field = hist_data->fields[i];
if (hist_field && hist_field->flags & HIST_FIELD_FL_VAR &&
strcmp(hist_field->var.name, var_name) == 0) {
found = hist_field;
break;
}
}
return found;
}
static struct hist_field *find_var(struct hist_trigger_data *hist_data,
struct trace_event_file *file,
const char *var_name)
{
struct hist_trigger_data *test_data;
struct event_trigger_data *test;
struct hist_field *hist_field;
hist_field = find_var_field(hist_data, var_name);
if (hist_field)
return hist_field;
list_for_each_entry_rcu(test, &file->triggers, list) {
if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) {
test_data = test->private_data;
hist_field = find_var_field(test_data, var_name);
if (hist_field)
return hist_field;
}
}
return NULL;
}
static const char *hist_field_name(struct hist_field *field,
unsigned int level)
{
......@@ -262,9 +326,14 @@ static int parse_map_size(char *str)
static void destroy_hist_trigger_attrs(struct hist_trigger_attrs *attrs)
{
unsigned int i;
if (!attrs)
return;
for (i = 0; i < attrs->n_assignments; i++)
kfree(attrs->assignment_str[i]);
kfree(attrs->name);
kfree(attrs->sort_key_str);
kfree(attrs->keys_str);
......@@ -311,8 +380,22 @@ static int parse_assignment(char *str, struct hist_trigger_attrs *attrs)
goto out;
}
attrs->map_bits = map_bits;
} else
ret = -EINVAL;
} else {
char *assignment;
if (attrs->n_assignments == TRACING_MAP_VARS_MAX) {
ret = -EINVAL;
goto out;
}
assignment = kstrdup(str, GFP_KERNEL);
if (!assignment) {
ret = -ENOMEM;
goto out;
}
attrs->assignment_str[attrs->n_assignments++] = assignment;
}
out:
return ret;
}
......@@ -428,12 +511,15 @@ static void destroy_hist_field(struct hist_field *hist_field,
for (i = 0; i < HIST_FIELD_OPERANDS_MAX; i++)
destroy_hist_field(hist_field->operands[i], level + 1);
kfree(hist_field->var.name);
kfree(hist_field);
}
static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
struct ftrace_event_field *field,
unsigned long flags)
unsigned long flags,
char *var_name)
{
struct hist_field *hist_field;
......@@ -459,7 +545,7 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
if (flags & HIST_FIELD_FL_LOG2) {
unsigned long fl = flags & ~HIST_FIELD_FL_LOG2;
hist_field->fn = hist_field_log2;
hist_field->operands[0] = create_hist_field(hist_data, field, fl);
hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
hist_field->size = hist_field->operands[0]->size;
goto out;
}
......@@ -494,14 +580,23 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
hist_field->field = field;
hist_field->flags = flags;
if (var_name) {
hist_field->var.name = kstrdup(var_name, GFP_KERNEL);
if (!hist_field->var.name)
goto free;
}
return hist_field;
free:
destroy_hist_field(hist_field, 0);
return NULL;
}
static void destroy_hist_fields(struct hist_trigger_data *hist_data)
{
unsigned int i;
for (i = 0; i < TRACING_MAP_FIELDS_MAX; i++) {
for (i = 0; i < HIST_FIELDS_MAX; i++) {
if (hist_data->fields[i]) {
destroy_hist_field(hist_data->fields[i], 0);
hist_data->fields[i] = NULL;
......@@ -512,11 +607,12 @@ static void destroy_hist_fields(struct hist_trigger_data *hist_data)
static int create_hitcount_val(struct hist_trigger_data *hist_data)
{
hist_data->fields[HITCOUNT_IDX] =
create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT);
create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT, NULL);
if (!hist_data->fields[HITCOUNT_IDX])
return -ENOMEM;
hist_data->n_vals++;
hist_data->n_fields++;
if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
return -EINVAL;
......@@ -524,19 +620,16 @@ static int create_hitcount_val(struct hist_trigger_data *hist_data)
return 0;
}
static int create_val_field(struct hist_trigger_data *hist_data,
unsigned int val_idx,
struct trace_event_file *file,
char *field_str)
static int __create_val_field(struct hist_trigger_data *hist_data,
unsigned int val_idx,
struct trace_event_file *file,
char *var_name, char *field_str,
unsigned long flags)
{
struct ftrace_event_field *field = NULL;
unsigned long flags = 0;
char *field_name;
int ret = 0;
if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
return -EINVAL;
field_name = strsep(&field_str, ".");
if (field_str) {
if (strcmp(field_str, "hex") == 0)
......@@ -558,25 +651,58 @@ static int create_val_field(struct hist_trigger_data *hist_data,
}
}
hist_data->fields[val_idx] = create_hist_field(hist_data, field, flags);
hist_data->fields[val_idx] = create_hist_field(hist_data, field, flags, var_name);
if (!hist_data->fields[val_idx]) {
ret = -ENOMEM;
goto out;
}
++hist_data->n_vals;
++hist_data->n_fields;
if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX))
if (WARN_ON(hist_data->n_vals > TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
ret = -EINVAL;
out:
return ret;
}
static int create_val_field(struct hist_trigger_data *hist_data,
unsigned int val_idx,
struct trace_event_file *file,
char *field_str)
{
if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX))
return -EINVAL;
return __create_val_field(hist_data, val_idx, file, NULL, field_str, 0);
}
static int create_var_field(struct hist_trigger_data *hist_data,
unsigned int val_idx,
struct trace_event_file *file,
char *var_name, char *expr_str)
{
unsigned long flags = 0;
if (WARN_ON(val_idx >= TRACING_MAP_VALS_MAX + TRACING_MAP_VARS_MAX))
return -EINVAL;
if (find_var(hist_data, file, var_name) && !hist_data->remove) {
return -EINVAL;
}
flags |= HIST_FIELD_FL_VAR;
hist_data->n_vars++;
if (WARN_ON(hist_data->n_vars > TRACING_MAP_VARS_MAX))
return -EINVAL;
return __create_val_field(hist_data, val_idx, file, var_name, expr_str, flags);
}
static int create_val_fields(struct hist_trigger_data *hist_data,
struct trace_event_file *file)
{
char *fields_str, *field_str;
unsigned int i, j;
unsigned int i, j = 1;
int ret;
ret = create_hitcount_val(hist_data);
......@@ -596,12 +722,15 @@ static int create_val_fields(struct hist_trigger_data *hist_data,
field_str = strsep(&fields_str, ",");
if (!field_str)
break;
if (strcmp(field_str, "hitcount") == 0)
continue;
ret = create_val_field(hist_data, j++, file, field_str);
if (ret)
goto out;
}
if (fields_str && (strcmp(fields_str, "hitcount") != 0))
ret = -EINVAL;
out:
......@@ -615,11 +744,12 @@ static int create_key_field(struct hist_trigger_data *hist_data,
char *field_str)
{
struct ftrace_event_field *field = NULL;
struct hist_field *hist_field = NULL;
unsigned long flags = 0;
unsigned int key_size;
int ret = 0;
if (WARN_ON(key_idx >= TRACING_MAP_FIELDS_MAX))
if (WARN_ON(key_idx >= HIST_FIELDS_MAX))
return -EINVAL;
flags |= HIST_FIELD_FL_KEY;
......@@ -627,6 +757,7 @@ static int create_key_field(struct hist_trigger_data *hist_data,
if (strcmp(field_str, "stacktrace") == 0) {
flags |= HIST_FIELD_FL_STACKTRACE;
key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
hist_field = create_hist_field(hist_data, NULL, flags, NULL);
} else {
char *field_name = strsep(&field_str, ".");
......@@ -672,7 +803,7 @@ static int create_key_field(struct hist_trigger_data *hist_data,
}
}
hist_data->fields[key_idx] = create_hist_field(hist_data, field, flags);
hist_data->fields[key_idx] = create_hist_field(hist_data, field, flags, NULL);
if (!hist_data->fields[key_idx]) {
ret = -ENOMEM;
goto out;
......@@ -688,6 +819,7 @@ static int create_key_field(struct hist_trigger_data *hist_data,
}
hist_data->n_keys++;
hist_data->n_fields++;
if (WARN_ON(hist_data->n_keys > TRACING_MAP_KEYS_MAX))
return -EINVAL;
......@@ -731,21 +863,111 @@ static int create_key_fields(struct hist_trigger_data *hist_data,
return ret;
}
static int create_var_fields(struct hist_trigger_data *hist_data,
struct trace_event_file *file)
{
unsigned int i, j = hist_data->n_vals;
int ret = 0;
unsigned int n_vars = hist_data->attrs->var_defs.n_vars;
for (i = 0; i < n_vars; i++) {
char *var_name = hist_data->attrs->var_defs.name[i];
char *expr = hist_data->attrs->var_defs.expr[i];
ret = create_var_field(hist_data, j++, file, var_name, expr);
if (ret)
goto out;
}
out:
return ret;
}
static void free_var_defs(struct hist_trigger_data *hist_data)
{
unsigned int i;
for (i = 0; i < hist_data->attrs->var_defs.n_vars; i++) {
kfree(hist_data->attrs->var_defs.name[i]);
kfree(hist_data->attrs->var_defs.expr[i]);
}
hist_data->attrs->var_defs.n_vars = 0;
}
static int parse_var_defs(struct hist_trigger_data *hist_data)
{
char *s, *str, *var_name, *field_str;
unsigned int i, j, n_vars = 0;
int ret = 0;
for (i = 0; i < hist_data->attrs->n_assignments; i++) {
str = hist_data->attrs->assignment_str[i];
for (j = 0; j < TRACING_MAP_VARS_MAX; j++) {
field_str = strsep(&str, ",");
if (!field_str)
break;
var_name = strsep(&field_str, "=");
if (!var_name || !field_str) {
ret = -EINVAL;
goto free;
}
if (n_vars == TRACING_MAP_VARS_MAX) {
ret = -EINVAL;
goto free;
}
s = kstrdup(var_name, GFP_KERNEL);
if (!s) {
ret = -ENOMEM;
goto free;
}
hist_data->attrs->var_defs.name[n_vars] = s;
s = kstrdup(field_str, GFP_KERNEL);
if (!s) {
kfree(hist_data->attrs->var_defs.name[n_vars]);
ret = -ENOMEM;
goto free;
}
hist_data->attrs->var_defs.expr[n_vars++] = s;
hist_data->attrs->var_defs.n_vars = n_vars;
}
}
return ret;
free:
free_var_defs(hist_data);
return ret;
}
static int create_hist_fields(struct hist_trigger_data *hist_data,
struct trace_event_file *file)
{
int ret;
ret = parse_var_defs(hist_data);
if (ret)
goto out;
ret = create_val_fields(hist_data, file);
if (ret)
goto out;
ret = create_key_fields(hist_data, file);
ret = create_var_fields(hist_data, file);
if (ret)
goto out;
hist_data->n_fields = hist_data->n_vals + hist_data->n_keys;
ret = create_key_fields(hist_data, file);
if (ret)
goto out;
out:
free_var_defs(hist_data);
return ret;
}
......@@ -768,7 +990,7 @@ static int create_sort_keys(struct hist_trigger_data *hist_data)
char *fields_str = hist_data->attrs->sort_key_str;
struct tracing_map_sort_key *sort_key;
int descending, ret = 0;
unsigned int i, j;
unsigned int i, j, k;
hist_data->n_sort_keys = 1; /* we always have at least one, hitcount */
......@@ -816,12 +1038,19 @@ static int create_sort_keys(struct hist_trigger_data *hist_data)
continue;
}
for (j = 1; j < hist_data->n_fields; j++) {
for (j = 1, k = 1; j < hist_data->n_fields; j++) {
unsigned int idx;
hist_field = hist_data->fields[j];
if (hist_field->flags & HIST_FIELD_FL_VAR)
continue;
idx = k++;
test_name = hist_field_name(hist_field, 0);
if (strcmp(field_name, test_name) == 0) {
sort_key->field_idx = j;
sort_key->field_idx = idx;
descending = is_descending(field_str);
if (descending < 0) {
ret = descending;
......@@ -836,6 +1065,7 @@ static int create_sort_keys(struct hist_trigger_data *hist_data)
break;
}
}
hist_data->n_sort_keys = i;
out:
return ret;
......@@ -876,12 +1106,19 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
idx = tracing_map_add_key_field(map,
hist_field->offset,
cmp_fn);
} else
} else if (!(hist_field->flags & HIST_FIELD_FL_VAR))
idx = tracing_map_add_sum_field(map);
if (idx < 0)
return idx;
if (hist_field->flags & HIST_FIELD_FL_VAR) {
idx = tracing_map_add_var(map);
if (idx < 0)
return idx;
hist_field->var.idx = idx;
hist_field->var.hist_data = hist_data;
}
}
return 0;
......@@ -905,7 +1142,8 @@ static bool need_tracing_map_ops(struct hist_trigger_data *hist_data)
static struct hist_trigger_data *
create_hist_data(unsigned int map_bits,
struct hist_trigger_attrs *attrs,
struct trace_event_file *file)
struct trace_event_file *file,
bool remove)
{
const struct tracing_map_ops *map_ops = NULL;
struct hist_trigger_data *hist_data;
......@@ -916,6 +1154,7 @@ create_hist_data(unsigned int map_bits,
return ERR_PTR(-ENOMEM);
hist_data->attrs = attrs;
hist_data->remove = remove;
ret = create_hist_fields(hist_data, file);
if (ret)
......@@ -962,14 +1201,28 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
struct ring_buffer_event *rbe)
{
struct hist_field *hist_field;
unsigned int i;
unsigned int i, var_idx;
u64 hist_val;
for_each_hist_val_field(i, hist_data) {
hist_field = hist_data->fields[i];
hist_val = hist_field->fn(hist_field, rec, rbe);
if (hist_field->flags & HIST_FIELD_FL_VAR) {
var_idx = hist_field->var.idx;
tracing_map_set_var(elt, var_idx, hist_val);
continue;
}
tracing_map_update_sum(elt, i, hist_val);
}
for_each_hist_key_field(i, hist_data) {
hist_field = hist_data->fields[i];
if (hist_field->flags & HIST_FIELD_FL_VAR) {
hist_val = hist_field->fn(hist_field, rec, rbe);
var_idx = hist_field->var.idx;
tracing_map_set_var(elt, var_idx, hist_val);
}
}
}
static inline void add_to_key(char *compound_key, void *key,
......@@ -1144,6 +1397,9 @@ hist_trigger_entry_print(struct seq_file *m,
for (i = 1; i < hist_data->n_vals; i++) {
field_name = hist_field_name(hist_data->fields[i], 0);
if (hist_data->fields[i]->flags & HIST_FIELD_FL_VAR)
continue;
if (hist_data->fields[i]->flags & HIST_FIELD_FL_HEX) {
seq_printf(m, " %s: %10llx", field_name,
tracing_map_read_sum(elt, i));
......@@ -1265,6 +1521,9 @@ static void hist_field_print(struct seq_file *m, struct hist_field *hist_field)
{
const char *field_name = hist_field_name(hist_field, 0);
if (hist_field->var.name)
seq_printf(m, "%s=", hist_field->var.name);
if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP)
seq_puts(m, "common_timestamp");
else if (field_name)
......@@ -1283,7 +1542,8 @@ static int event_hist_trigger_print(struct seq_file *m,
struct event_trigger_data *data)
{
struct hist_trigger_data *hist_data = data->private_data;
struct hist_field *key_field;
struct hist_field *field;
bool have_var = false;
unsigned int i;
seq_puts(m, "hist:");
......@@ -1294,25 +1554,47 @@ static int event_hist_trigger_print(struct seq_file *m,
seq_puts(m, "keys=");
for_each_hist_key_field(i, hist_data) {
key_field = hist_data->fields[i];
field = hist_data->fields[i];
if (i > hist_data->n_vals)
seq_puts(m, ",");
if (key_field->flags & HIST_FIELD_FL_STACKTRACE)
if (field->flags & HIST_FIELD_FL_STACKTRACE)
seq_puts(m, "stacktrace");
else
hist_field_print(m, key_field);
hist_field_print(m, field);
}
seq_puts(m, ":vals=");
for_each_hist_val_field(i, hist_data) {
field = hist_data->fields[i];
if (field->flags & HIST_FIELD_FL_VAR) {
have_var = true;
continue;
}
if (i == HITCOUNT_IDX)
seq_puts(m, "hitcount");
else {
seq_puts(m, ",");
hist_field_print(m, hist_data->fields[i]);
hist_field_print(m, field);
}
}
if (have_var) {
unsigned int n = 0;
seq_puts(m, ":");
for_each_hist_val_field(i, hist_data) {
field = hist_data->fields[i];
if (field->flags & HIST_FIELD_FL_VAR) {
if (n++)
seq_puts(m, ",");
hist_field_print(m, field);
}
}
}
......@@ -1320,7 +1602,10 @@ static int event_hist_trigger_print(struct seq_file *m,
for (i = 0; i < hist_data->n_sort_keys; i++) {
struct tracing_map_sort_key *sort_key;
unsigned int idx;
unsigned int idx, first_key_idx;
/* skip VAR vals */
first_key_idx = hist_data->n_vals - hist_data->n_vars;
sort_key = &hist_data->sort_keys[i];
idx = sort_key->field_idx;
......@@ -1333,8 +1618,11 @@ static int event_hist_trigger_print(struct seq_file *m,
if (idx == HITCOUNT_IDX)
seq_puts(m, "hitcount");
else
else {
if (idx >= first_key_idx)
idx += hist_data->n_vars;
hist_field_print(m, hist_data->fields[idx]);
}
if (sort_key->descending)
seq_puts(m, ".descending");
......@@ -1631,7 +1919,7 @@ static void hist_unregister_trigger(char *glob, struct event_trigger_ops *ops,
test->ops->free(test->ops, test);
if (hist_data->enable_timestamps) {
if (unregistered)
if (!hist_data->remove || unregistered)
tracing_set_time_stamp_abs(file->tr, false);
}
}
......@@ -1664,12 +1952,16 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,
struct hist_trigger_attrs *attrs;
struct event_trigger_ops *trigger_ops;
struct hist_trigger_data *hist_data;
bool remove = false;
char *trigger;
int ret = 0;
if (!param)
return -EINVAL;
if (glob[0] == '!')
remove = true;
/* separate the trigger from the filter (k:v [if filter]) */
trigger = strsep(&param, " \t");
if (!trigger)
......@@ -1682,7 +1974,7 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,
if (attrs->map_bits)
hist_trigger_bits = attrs->map_bits;
hist_data = create_hist_data(hist_trigger_bits, attrs, file);
hist_data = create_hist_data(hist_trigger_bits, attrs, file, remove);
if (IS_ERR(hist_data)) {
destroy_hist_trigger_attrs(attrs);
return PTR_ERR(hist_data);
......@@ -1711,7 +2003,7 @@ static int event_hist_trigger_func(struct event_command *cmd_ops,
goto out_free;
}
if (glob[0] == '!') {
if (remove) {
cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file);
ret = 0;
goto out_free;
......
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