tracing/filters: improve subsystem filter
Currently a subsystem filter should be applicable to all events under the subsystem, and if it failed, all the event filters will be cleared. Those behaviors make subsys filter much less useful: # echo 'vec == 1' > irq/softirq_entry/filter # echo 'irq == 5' > irq/filter bash: echo: write error: Invalid argument # cat irq/softirq_entry/filter none I'd expect it set the filter for irq_handler_entry/exit, and not touch softirq_entry/exit. The basic idea is, try to see if the filter can be applied to which events, and then just apply to the those events: # echo 'vec == 1' > softirq_entry/filter # echo 'irq == 5' > filter # cat irq_handler_entry/filter irq == 5 # cat softirq_entry/filter vec == 1 Changelog for v2: - do some cleanups to address Frederic's comments. Inspired-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4A63D485.7030703@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Li Zefan
Steven Rostedt
Родитель
ff4e9da233
Коммит
1f9963cbb0
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@ -101,6 +101,8 @@ void trace_current_buffer_discard_commit(struct ring_buffer_event *event);
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void tracing_record_cmdline(struct task_struct *tsk);
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struct event_filter;
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struct ftrace_event_call {
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struct list_head list;
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char *name;
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@ -116,7 +118,7 @@ struct ftrace_event_call {
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int (*define_fields)(void);
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struct list_head fields;
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int filter_active;
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void *filter;
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struct event_filter *filter;
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void *mod;
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#ifdef CONFIG_EVENT_PROFILE
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@ -750,13 +750,14 @@ struct event_filter {
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int n_preds;
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struct filter_pred **preds;
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char *filter_string;
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bool no_reset;
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};
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struct event_subsystem {
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struct list_head list;
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const char *name;
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struct dentry *entry;
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void *filter;
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struct event_filter *filter;
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int nr_events;
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};
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@ -420,7 +420,14 @@ oom:
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}
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EXPORT_SYMBOL_GPL(init_preds);
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static void filter_free_subsystem_preds(struct event_subsystem *system)
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enum {
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FILTER_DISABLE_ALL,
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FILTER_INIT_NO_RESET,
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FILTER_SKIP_NO_RESET,
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};
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static void filter_free_subsystem_preds(struct event_subsystem *system,
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int flag)
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{
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struct ftrace_event_call *call;
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@ -428,6 +435,14 @@ static void filter_free_subsystem_preds(struct event_subsystem *system)
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if (!call->define_fields)
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continue;
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if (flag == FILTER_INIT_NO_RESET) {
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call->filter->no_reset = false;
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continue;
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}
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if (flag == FILTER_SKIP_NO_RESET && call->filter->no_reset)
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continue;
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if (!strcmp(call->system, system->name)) {
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filter_disable_preds(call);
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remove_filter_string(call->filter);
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@ -529,7 +544,8 @@ static filter_pred_fn_t select_comparison_fn(int op, int field_size,
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static int filter_add_pred(struct filter_parse_state *ps,
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struct ftrace_event_call *call,
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struct filter_pred *pred)
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struct filter_pred *pred,
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bool dry_run)
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{
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struct ftrace_event_field *field;
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filter_pred_fn_t fn;
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@ -541,10 +557,12 @@ static int filter_add_pred(struct filter_parse_state *ps,
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if (pred->op == OP_AND) {
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pred->pop_n = 2;
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return filter_add_pred_fn(ps, call, pred, filter_pred_and);
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fn = filter_pred_and;
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goto add_pred_fn;
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} else if (pred->op == OP_OR) {
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pred->pop_n = 2;
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return filter_add_pred_fn(ps, call, pred, filter_pred_or);
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fn = filter_pred_or;
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goto add_pred_fn;
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}
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field = find_event_field(call, pred->field_name);
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@ -567,9 +585,6 @@ static int filter_add_pred(struct filter_parse_state *ps,
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else
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fn = filter_pred_strloc;
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pred->str_len = field->size;
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if (pred->op == OP_NE)
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pred->not = 1;
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return filter_add_pred_fn(ps, call, pred, fn);
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} else {
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if (field->is_signed)
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ret = strict_strtoll(pred->str_val, 0, &val);
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@ -580,27 +595,33 @@ static int filter_add_pred(struct filter_parse_state *ps,
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return -EINVAL;
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}
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pred->val = val;
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}
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fn = select_comparison_fn(pred->op, field->size, field->is_signed);
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if (!fn) {
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parse_error(ps, FILT_ERR_INVALID_OP, 0);
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return -EINVAL;
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fn = select_comparison_fn(pred->op, field->size,
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field->is_signed);
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if (!fn) {
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parse_error(ps, FILT_ERR_INVALID_OP, 0);
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return -EINVAL;
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}
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}
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if (pred->op == OP_NE)
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pred->not = 1;
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return filter_add_pred_fn(ps, call, pred, fn);
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add_pred_fn:
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if (!dry_run)
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return filter_add_pred_fn(ps, call, pred, fn);
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return 0;
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}
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static int filter_add_subsystem_pred(struct filter_parse_state *ps,
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struct event_subsystem *system,
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struct filter_pred *pred,
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char *filter_string)
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char *filter_string,
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bool dry_run)
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{
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struct ftrace_event_call *call;
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int err = 0;
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bool fail = true;
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list_for_each_entry(call, &ftrace_events, list) {
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@ -610,16 +631,24 @@ static int filter_add_subsystem_pred(struct filter_parse_state *ps,
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if (strcmp(call->system, system->name))
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continue;
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err = filter_add_pred(ps, call, pred);
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if (err) {
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filter_free_subsystem_preds(system);
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parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
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goto out;
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}
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replace_filter_string(call->filter, filter_string);
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if (call->filter->no_reset)
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continue;
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err = filter_add_pred(ps, call, pred, dry_run);
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if (err)
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call->filter->no_reset = true;
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else
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fail = false;
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if (!dry_run)
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replace_filter_string(call->filter, filter_string);
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}
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out:
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return err;
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if (fail) {
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parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
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return err;
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}
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return 0;
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}
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static void parse_init(struct filter_parse_state *ps,
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@ -978,12 +1007,14 @@ static int check_preds(struct filter_parse_state *ps)
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static int replace_preds(struct event_subsystem *system,
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struct ftrace_event_call *call,
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struct filter_parse_state *ps,
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char *filter_string)
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char *filter_string,
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bool dry_run)
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{
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char *operand1 = NULL, *operand2 = NULL;
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struct filter_pred *pred;
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struct postfix_elt *elt;
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int err;
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int n_preds = 0;
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err = check_preds(ps);
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if (err)
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@ -1002,19 +1033,14 @@ static int replace_preds(struct event_subsystem *system,
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continue;
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}
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if (n_preds++ == MAX_FILTER_PRED) {
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parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
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return -ENOSPC;
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}
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if (elt->op == OP_AND || elt->op == OP_OR) {
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pred = create_logical_pred(elt->op);
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if (call)
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err = filter_add_pred(ps, call, pred);
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else
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err = filter_add_subsystem_pred(ps, system,
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pred, filter_string);
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filter_free_pred(pred);
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if (err)
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return err;
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operand1 = operand2 = NULL;
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continue;
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goto add_pred;
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}
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if (!operand1 || !operand2) {
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@ -1023,11 +1049,12 @@ static int replace_preds(struct event_subsystem *system,
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}
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pred = create_pred(elt->op, operand1, operand2);
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add_pred:
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if (call)
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err = filter_add_pred(ps, call, pred);
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err = filter_add_pred(ps, call, pred, false);
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else
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err = filter_add_subsystem_pred(ps, system, pred,
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filter_string);
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filter_string, dry_run);
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filter_free_pred(pred);
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if (err)
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return err;
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@ -1068,7 +1095,7 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
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goto out;
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}
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err = replace_preds(NULL, call, ps, filter_string);
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err = replace_preds(NULL, call, ps, filter_string, false);
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if (err)
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append_filter_err(ps, call->filter);
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@ -1092,7 +1119,7 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
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mutex_lock(&event_mutex);
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if (!strcmp(strstrip(filter_string), "0")) {
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filter_free_subsystem_preds(system);
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filter_free_subsystem_preds(system, FILTER_DISABLE_ALL);
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remove_filter_string(system->filter);
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mutex_unlock(&event_mutex);
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return 0;
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@ -1103,7 +1130,6 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
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if (!ps)
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goto out_unlock;
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filter_free_subsystem_preds(system);
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replace_filter_string(system->filter, filter_string);
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parse_init(ps, filter_ops, filter_string);
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@ -1113,9 +1139,23 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
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goto out;
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}
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err = replace_preds(system, NULL, ps, filter_string);
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if (err)
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filter_free_subsystem_preds(system, FILTER_INIT_NO_RESET);
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/* try to see the filter can be applied to which events */
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err = replace_preds(system, NULL, ps, filter_string, true);
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if (err) {
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append_filter_err(ps, system->filter);
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goto out;
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}
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filter_free_subsystem_preds(system, FILTER_SKIP_NO_RESET);
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/* really apply the filter to the events */
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err = replace_preds(system, NULL, ps, filter_string, false);
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if (err) {
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append_filter_err(ps, system->filter);
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filter_free_subsystem_preds(system, 2);
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}
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out:
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filter_opstack_clear(ps);
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