| From: Tom Zanussi <tom.zanussi@linux.intel.com> |
| Date: Tue, 5 Sep 2017 16:57:40 -0500 |
| Subject: [PATCH 28/40] tracing: Add support for 'field variables' |
| |
| Users should be able to directly specify event fields in hist trigger |
| 'actions' rather than being forced to explicitly create a variable for |
| that purpose. |
| |
| Add support allowing fields to be used directly in actions, which |
| essentially does just that - creates 'invisible' variables for each |
| bare field specified in an action. If a bare field refers to a field |
| on another (matching) event, it even creates a special histogram for |
| the purpose (since variables can't be defined on an existing histogram |
| after histogram creation). |
| |
| Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| kernel/trace/trace_events_hist.c | 452 ++++++++++++++++++++++++++++++++++++++- |
| 1 file changed, 451 insertions(+), 1 deletion(-) |
| |
| --- a/kernel/trace/trace_events_hist.c |
| +++ b/kernel/trace/trace_events_hist.c |
| @@ -254,6 +254,16 @@ struct hist_trigger_attrs { |
| struct var_defs var_defs; |
| }; |
| |
| +struct field_var { |
| + struct hist_field *var; |
| + struct hist_field *val; |
| +}; |
| + |
| +struct field_var_hist { |
| + struct hist_trigger_data *hist_data; |
| + char *cmd; |
| +}; |
| + |
| struct hist_trigger_data { |
| struct hist_field *fields[HIST_FIELDS_MAX]; |
| unsigned int n_vals; |
| @@ -274,6 +284,14 @@ struct hist_trigger_data { |
| |
| struct action_data *actions[HIST_ACTIONS_MAX]; |
| unsigned int n_actions; |
| + |
| + struct hist_field *synth_var_refs[SYNTH_FIELDS_MAX]; |
| + unsigned int n_synth_var_refs; |
| + struct field_var *field_vars[SYNTH_FIELDS_MAX]; |
| + unsigned int n_field_vars; |
| + unsigned int n_field_var_str; |
| + struct field_var_hist *field_var_hists[SYNTH_FIELDS_MAX]; |
| + unsigned int n_field_var_hists; |
| }; |
| |
| struct synth_field { |
| @@ -1392,6 +1410,7 @@ static struct hist_field *find_event_var |
| struct hist_elt_data { |
| char *comm; |
| u64 *var_ref_vals; |
| + char *field_var_str[SYNTH_FIELDS_MAX]; |
| }; |
| |
| static u64 hist_field_var_ref(struct hist_field *hist_field, |
| @@ -1669,7 +1688,14 @@ static inline void save_comm(char *comm, |
| |
| static void hist_trigger_elt_data_free(struct tracing_map_elt *elt) |
| { |
| + struct hist_trigger_data *hist_data = elt->map->private_data; |
| struct hist_elt_data *private_data = elt->private_data; |
| + unsigned int i, n_str; |
| + |
| + n_str = hist_data->n_field_var_str; |
| + |
| + for (i = 0; i < n_str; i++) |
| + kfree(private_data->field_var_str[i]); |
| |
| kfree(private_data->comm); |
| kfree(private_data); |
| @@ -1681,7 +1707,7 @@ static int hist_trigger_elt_data_alloc(s |
| unsigned int size = TASK_COMM_LEN + 1; |
| struct hist_elt_data *elt_data; |
| struct hist_field *key_field; |
| - unsigned int i; |
| + unsigned int i, n_str; |
| |
| elt->private_data = elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL); |
| if (!elt_data) |
| @@ -1701,6 +1727,18 @@ static int hist_trigger_elt_data_alloc(s |
| } |
| } |
| |
| + n_str = hist_data->n_field_var_str; |
| + |
| + size = STR_VAR_LEN_MAX; |
| + |
| + for (i = 0; i < n_str; i++) { |
| + elt_data->field_var_str[i] = kzalloc(size, GFP_KERNEL); |
| + if (!elt_data->field_var_str[i]) { |
| + hist_trigger_elt_data_free(elt); |
| + return -ENOMEM; |
| + } |
| + } |
| + |
| return 0; |
| } |
| |
| @@ -2347,6 +2385,387 @@ static struct hist_field *parse_expr(str |
| return ERR_PTR(ret); |
| } |
| |
| +static char *find_trigger_filter(struct hist_trigger_data *hist_data, |
| + struct trace_event_file *file) |
| +{ |
| + struct event_trigger_data *test; |
| + |
| + list_for_each_entry_rcu(test, &file->triggers, list) { |
| + if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) { |
| + if (test->private_data == hist_data) |
| + return test->filter_str; |
| + } |
| + } |
| + |
| + return NULL; |
| +} |
| + |
| +static struct event_command trigger_hist_cmd; |
| +static int event_hist_trigger_func(struct event_command *cmd_ops, |
| + struct trace_event_file *file, |
| + char *glob, char *cmd, char *param); |
| + |
| +static bool compatible_keys(struct hist_trigger_data *target_hist_data, |
| + struct hist_trigger_data *hist_data, |
| + unsigned int n_keys) |
| +{ |
| + struct hist_field *target_hist_field, *hist_field; |
| + unsigned int n, i, j; |
| + |
| + if (hist_data->n_fields - hist_data->n_vals != n_keys) |
| + return false; |
| + |
| + i = hist_data->n_vals; |
| + j = target_hist_data->n_vals; |
| + |
| + for (n = 0; n < n_keys; n++) { |
| + hist_field = hist_data->fields[i + n]; |
| + target_hist_field = hist_data->fields[j + n]; |
| + |
| + if (strcmp(hist_field->type, target_hist_field->type) != 0) |
| + return false; |
| + if (hist_field->size != target_hist_field->size) |
| + return false; |
| + if (hist_field->is_signed != target_hist_field->is_signed) |
| + return false; |
| + } |
| + |
| + return true; |
| +} |
| + |
| +static struct hist_trigger_data * |
| +find_compatible_hist(struct hist_trigger_data *target_hist_data, |
| + struct trace_event_file *file) |
| +{ |
| + struct hist_trigger_data *hist_data; |
| + struct event_trigger_data *test; |
| + unsigned int n_keys; |
| + |
| + n_keys = target_hist_data->n_fields - target_hist_data->n_vals; |
| + |
| + list_for_each_entry_rcu(test, &file->triggers, list) { |
| + if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) { |
| + hist_data = test->private_data; |
| + |
| + if (compatible_keys(target_hist_data, hist_data, n_keys)) |
| + return hist_data; |
| + } |
| + } |
| + |
| + return NULL; |
| +} |
| + |
| +static struct trace_event_file *event_file(struct trace_array *tr, |
| + char *system, char *event_name) |
| +{ |
| + struct trace_event_file *file; |
| + |
| + file = find_event_file(tr, system, event_name); |
| + if (!file) |
| + return ERR_PTR(-EINVAL); |
| + |
| + return file; |
| +} |
| + |
| +static struct hist_field * |
| +create_field_var_hist(struct hist_trigger_data *target_hist_data, |
| + char *system, char *event_name, char *field_name) |
| +{ |
| + struct trace_array *tr = target_hist_data->event_file->tr; |
| + struct hist_field *event_var = ERR_PTR(-EINVAL); |
| + struct hist_trigger_data *hist_data; |
| + unsigned int i, n, first = true; |
| + struct field_var_hist *var_hist; |
| + struct trace_event_file *file; |
| + struct hist_field *key_field; |
| + char *saved_filter; |
| + char *cmd; |
| + int ret; |
| + |
| + if (target_hist_data->n_field_var_hists >= SYNTH_FIELDS_MAX) |
| + return ERR_PTR(-EINVAL); |
| + |
| + file = event_file(tr, system, event_name); |
| + |
| + if (IS_ERR(file)) { |
| + ret = PTR_ERR(file); |
| + return ERR_PTR(ret); |
| + } |
| + |
| + hist_data = find_compatible_hist(target_hist_data, file); |
| + if (!hist_data) |
| + return ERR_PTR(-EINVAL); |
| + |
| + var_hist = kzalloc(sizeof(*var_hist), GFP_KERNEL); |
| + if (!var_hist) |
| + return ERR_PTR(-ENOMEM); |
| + |
| + cmd = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL); |
| + if (!cmd) { |
| + kfree(var_hist); |
| + return ERR_PTR(-ENOMEM); |
| + } |
| + |
| + strcat(cmd, "keys="); |
| + |
| + for_each_hist_key_field(i, hist_data) { |
| + key_field = hist_data->fields[i]; |
| + if (!first) |
| + strcat(cmd, ","); |
| + strcat(cmd, key_field->field->name); |
| + first = false; |
| + } |
| + |
| + strcat(cmd, ":synthetic_"); |
| + strcat(cmd, field_name); |
| + strcat(cmd, "="); |
| + strcat(cmd, field_name); |
| + |
| + saved_filter = find_trigger_filter(hist_data, file); |
| + if (saved_filter) { |
| + strcat(cmd, " if "); |
| + strcat(cmd, saved_filter); |
| + } |
| + |
| + var_hist->cmd = kstrdup(cmd, GFP_KERNEL); |
| + if (!var_hist->cmd) { |
| + kfree(cmd); |
| + kfree(var_hist); |
| + return ERR_PTR(-ENOMEM); |
| + } |
| + |
| + var_hist->hist_data = hist_data; |
| + |
| + ret = event_hist_trigger_func(&trigger_hist_cmd, file, |
| + "", "hist", cmd); |
| + if (ret) { |
| + kfree(cmd); |
| + kfree(var_hist->cmd); |
| + kfree(var_hist); |
| + return ERR_PTR(ret); |
| + } |
| + |
| + strcpy(cmd, "synthetic_"); |
| + strcat(cmd, field_name); |
| + |
| + event_var = find_event_var(tr, system, event_name, cmd); |
| + if (!event_var) { |
| + kfree(cmd); |
| + kfree(var_hist->cmd); |
| + kfree(var_hist); |
| + return ERR_PTR(-EINVAL); |
| + } |
| + |
| + n = target_hist_data->n_field_var_hists; |
| + target_hist_data->field_var_hists[n] = var_hist; |
| + target_hist_data->n_field_var_hists++; |
| + |
| + return event_var; |
| +} |
| + |
| +static struct hist_field * |
| +find_target_event_var(struct hist_trigger_data *hist_data, |
| + char *system, char *event_name, char *var_name) |
| +{ |
| + struct trace_event_file *file = hist_data->event_file; |
| + struct hist_field *hist_field = NULL; |
| + |
| + if (system) { |
| + struct trace_event_call *call; |
| + |
| + if (!event_name) |
| + return NULL; |
| + |
| + call = file->event_call; |
| + |
| + if (strcmp(system, call->class->system) != 0) |
| + return NULL; |
| + |
| + if (strcmp(event_name, trace_event_name(call)) != 0) |
| + return NULL; |
| + } |
| + |
| + hist_field = find_var_field(hist_data, var_name); |
| + |
| + return hist_field; |
| +} |
| + |
| +static inline void __update_field_vars(struct tracing_map_elt *elt, |
| + struct ring_buffer_event *rbe, |
| + void *rec, |
| + struct field_var **field_vars, |
| + unsigned int n_field_vars, |
| + unsigned int field_var_str_start) |
| +{ |
| + struct hist_elt_data *elt_data = elt->private_data; |
| + unsigned int i, j, var_idx; |
| + u64 var_val; |
| + |
| + for (i = 0, j = field_var_str_start; i < n_field_vars; i++) { |
| + struct field_var *field_var = field_vars[i]; |
| + struct hist_field *var = field_var->var; |
| + struct hist_field *val = field_var->val; |
| + |
| + var_val = val->fn(val, elt, rbe, rec); |
| + var_idx = var->var.idx; |
| + |
| + if (val->flags & HIST_FIELD_FL_STRING) { |
| + char *str = elt_data->field_var_str[j++]; |
| + char *val_str = (char *)(uintptr_t)var_val; |
| + |
| + strncpy(str, val_str, STR_VAR_LEN_MAX); |
| + var_val = (u64)(uintptr_t)str; |
| + } |
| + tracing_map_set_var(elt, var_idx, var_val); |
| + } |
| +} |
| + |
| +static void update_field_vars(struct hist_trigger_data *hist_data, |
| + struct tracing_map_elt *elt, |
| + struct ring_buffer_event *rbe, |
| + void *rec) |
| +{ |
| + __update_field_vars(elt, rbe, rec, hist_data->field_vars, |
| + hist_data->n_field_vars, 0); |
| +} |
| + |
| +static struct hist_field *create_var(struct hist_trigger_data *hist_data, |
| + struct trace_event_file *file, |
| + char *name, int size, const char *type) |
| +{ |
| + struct hist_field *var; |
| + int idx; |
| + |
| + if (find_var(file, name) && !hist_data->remove) { |
| + var = ERR_PTR(-EINVAL); |
| + goto out; |
| + } |
| + |
| + var = kzalloc(sizeof(struct hist_field), GFP_KERNEL); |
| + if (!var) { |
| + var = ERR_PTR(-ENOMEM); |
| + goto out; |
| + } |
| + |
| + idx = tracing_map_add_var(hist_data->map); |
| + if (idx < 0) { |
| + kfree(var); |
| + var = ERR_PTR(-EINVAL); |
| + goto out; |
| + } |
| + |
| + var->flags = HIST_FIELD_FL_VAR; |
| + var->var.idx = idx; |
| + var->var.hist_data = var->hist_data = hist_data; |
| + var->size = size; |
| + var->var.name = kstrdup(name, GFP_KERNEL); |
| + var->type = kstrdup(type, GFP_KERNEL); |
| + if (!var->var.name || !var->type) { |
| + kfree(var->var.name); |
| + kfree(var->type); |
| + kfree(var); |
| + var = ERR_PTR(-ENOMEM); |
| + } |
| + out: |
| + return var; |
| +} |
| + |
| +static struct field_var *create_field_var(struct hist_trigger_data *hist_data, |
| + struct trace_event_file *file, |
| + char *field_name) |
| +{ |
| + struct hist_field *val = NULL, *var = NULL; |
| + unsigned long flags = HIST_FIELD_FL_VAR; |
| + struct field_var *field_var; |
| + int ret = 0; |
| + |
| + if (hist_data->n_field_vars >= SYNTH_FIELDS_MAX) { |
| + ret = -EINVAL; |
| + goto err; |
| + } |
| + |
| + val = parse_atom(hist_data, file, field_name, &flags, NULL); |
| + if (IS_ERR(val)) { |
| + ret = PTR_ERR(val); |
| + goto err; |
| + } |
| + |
| + var = create_var(hist_data, file, field_name, val->size, val->type); |
| + if (IS_ERR(var)) { |
| + kfree(val); |
| + ret = PTR_ERR(var); |
| + goto err; |
| + } |
| + |
| + field_var = kzalloc(sizeof(struct field_var), GFP_KERNEL); |
| + if (!field_var) { |
| + kfree(val); |
| + kfree(var); |
| + ret = -ENOMEM; |
| + goto err; |
| + } |
| + |
| + field_var->var = var; |
| + field_var->val = val; |
| + out: |
| + return field_var; |
| + err: |
| + field_var = ERR_PTR(ret); |
| + goto out; |
| +} |
| + |
| +static struct field_var * |
| +create_target_field_var(struct hist_trigger_data *hist_data, |
| + char *system, char *event_name, char *var_name) |
| +{ |
| + struct trace_event_file *file = hist_data->event_file; |
| + |
| + if (system) { |
| + struct trace_event_call *call; |
| + |
| + if (!event_name) |
| + return NULL; |
| + |
| + call = file->event_call; |
| + |
| + if (strcmp(system, call->class->system) != 0) |
| + return NULL; |
| + |
| + if (strcmp(event_name, trace_event_name(call)) != 0) |
| + return NULL; |
| + } |
| + |
| + return create_field_var(hist_data, file, var_name); |
| +} |
| + |
| +static void destroy_field_var(struct field_var *field_var) |
| +{ |
| + if (!field_var) |
| + return; |
| + |
| + destroy_hist_field(field_var->var, 0); |
| + destroy_hist_field(field_var->val, 0); |
| + |
| + kfree(field_var); |
| +} |
| + |
| +static void destroy_field_vars(struct hist_trigger_data *hist_data) |
| +{ |
| + unsigned int i; |
| + |
| + for (i = 0; i < hist_data->n_field_vars; i++) |
| + destroy_field_var(hist_data->field_vars[i]); |
| +} |
| + |
| +static void save_field_var(struct hist_trigger_data *hist_data, |
| + struct field_var *field_var) |
| +{ |
| + hist_data->field_vars[hist_data->n_field_vars++] = field_var; |
| + |
| + if (field_var->val->flags & HIST_FIELD_FL_STRING) |
| + hist_data->n_field_var_str++; |
| +} |
| + |
| static int create_hitcount_val(struct hist_trigger_data *hist_data) |
| { |
| hist_data->fields[HITCOUNT_IDX] = |
| @@ -2814,6 +3233,16 @@ static void print_actions_spec(struct se |
| } |
| } |
| |
| +static void destroy_field_var_hists(struct hist_trigger_data *hist_data) |
| +{ |
| + unsigned int i; |
| + |
| + for (i = 0; i < hist_data->n_field_var_hists; i++) { |
| + kfree(hist_data->field_var_hists[i]->cmd); |
| + kfree(hist_data->field_var_hists[i]); |
| + } |
| +} |
| + |
| static void destroy_hist_data(struct hist_trigger_data *hist_data) |
| { |
| if (!hist_data) |
| @@ -2824,6 +3253,8 @@ static void destroy_hist_data(struct his |
| tracing_map_destroy(hist_data->map); |
| |
| destroy_actions(hist_data); |
| + destroy_field_vars(hist_data); |
| + destroy_field_var_hists(hist_data); |
| |
| kfree(hist_data); |
| } |
| @@ -2957,6 +3388,8 @@ static void hist_trigger_elt_update(stru |
| tracing_map_set_var(elt, var_idx, hist_val); |
| } |
| } |
| + |
| + update_field_vars(hist_data, elt, rbe, rec); |
| } |
| |
| static inline void add_to_key(char *compound_key, void *key, |
| @@ -3677,6 +4110,21 @@ static bool hist_trigger_check_refs(stru |
| return false; |
| } |
| |
| +static void unregister_field_var_hists(struct hist_trigger_data *hist_data) |
| +{ |
| + struct trace_event_file *file; |
| + unsigned int i; |
| + char *cmd; |
| + int ret; |
| + |
| + for (i = 0; i < hist_data->n_field_var_hists; i++) { |
| + file = hist_data->field_var_hists[i]->hist_data->event_file; |
| + cmd = hist_data->field_var_hists[i]->cmd; |
| + ret = event_hist_trigger_func(&trigger_hist_cmd, file, |
| + "!hist", "hist", cmd); |
| + } |
| +} |
| + |
| static void hist_unregister_trigger(char *glob, struct event_trigger_ops *ops, |
| struct event_trigger_data *data, |
| struct trace_event_file *file) |
| @@ -3692,6 +4140,7 @@ static void hist_unregister_trigger(char |
| if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) { |
| if (!hist_trigger_match(data, test, named_data, false)) |
| continue; |
| + unregister_field_var_hists(test->private_data); |
| unregistered = true; |
| list_del_rcu(&test->list); |
| trace_event_trigger_enable_disable(file, 0); |
| @@ -3733,6 +4182,7 @@ static void hist_unreg_all(struct trace_ |
| |
| list_for_each_entry_safe(test, n, &file->triggers, list) { |
| if (test->cmd_ops->trigger_type == ETT_EVENT_HIST) { |
| + unregister_field_var_hists(test->private_data); |
| list_del_rcu(&test->list); |
| trace_event_trigger_enable_disable(file, 0); |
| update_cond_flag(file); |