Commit 1f9963cb authored by Li Zefan's avatar Li Zefan Committed by Steven Rostedt
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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: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Acked-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A63D485.7030703@cn.fujitsu.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent ff4e9da2
......@@ -101,6 +101,8 @@ void trace_current_buffer_discard_commit(struct ring_buffer_event *event);
void tracing_record_cmdline(struct task_struct *tsk);
struct event_filter;
struct ftrace_event_call {
struct list_head list;
char *name;
......@@ -116,7 +118,7 @@ struct ftrace_event_call {
int (*define_fields)(void);
struct list_head fields;
int filter_active;
void *filter;
struct event_filter *filter;
void *mod;
#ifdef CONFIG_EVENT_PROFILE
......
......@@ -750,13 +750,14 @@ struct event_filter {
int n_preds;
struct filter_pred **preds;
char *filter_string;
bool no_reset;
};
struct event_subsystem {
struct list_head list;
const char *name;
struct dentry *entry;
void *filter;
struct event_filter *filter;
int nr_events;
};
......
......@@ -420,7 +420,14 @@ oom:
}
EXPORT_SYMBOL_GPL(init_preds);
static void filter_free_subsystem_preds(struct event_subsystem *system)
enum {
FILTER_DISABLE_ALL,
FILTER_INIT_NO_RESET,
FILTER_SKIP_NO_RESET,
};
static void filter_free_subsystem_preds(struct event_subsystem *system,
int flag)
{
struct ftrace_event_call *call;
......@@ -428,6 +435,14 @@ static void filter_free_subsystem_preds(struct event_subsystem *system)
if (!call->define_fields)
continue;
if (flag == FILTER_INIT_NO_RESET) {
call->filter->no_reset = false;
continue;
}
if (flag == FILTER_SKIP_NO_RESET && call->filter->no_reset)
continue;
if (!strcmp(call->system, system->name)) {
filter_disable_preds(call);
remove_filter_string(call->filter);
......@@ -529,7 +544,8 @@ static filter_pred_fn_t select_comparison_fn(int op, int field_size,
static int filter_add_pred(struct filter_parse_state *ps,
struct ftrace_event_call *call,
struct filter_pred *pred)
struct filter_pred *pred,
bool dry_run)
{
struct ftrace_event_field *field;
filter_pred_fn_t fn;
......@@ -541,10 +557,12 @@ static int filter_add_pred(struct filter_parse_state *ps,
if (pred->op == OP_AND) {
pred->pop_n = 2;
return filter_add_pred_fn(ps, call, pred, filter_pred_and);
fn = filter_pred_and;
goto add_pred_fn;
} else if (pred->op == OP_OR) {
pred->pop_n = 2;
return filter_add_pred_fn(ps, call, pred, filter_pred_or);
fn = filter_pred_or;
goto add_pred_fn;
}
field = find_event_field(call, pred->field_name);
......@@ -567,9 +585,6 @@ static int filter_add_pred(struct filter_parse_state *ps,
else
fn = filter_pred_strloc;
pred->str_len = field->size;
if (pred->op == OP_NE)
pred->not = 1;
return filter_add_pred_fn(ps, call, pred, fn);
} else {
if (field->is_signed)
ret = strict_strtoll(pred->str_val, 0, &val);
......@@ -580,27 +595,33 @@ static int filter_add_pred(struct filter_parse_state *ps,
return -EINVAL;
}
pred->val = val;
}
fn = select_comparison_fn(pred->op, field->size, field->is_signed);
if (!fn) {
parse_error(ps, FILT_ERR_INVALID_OP, 0);
return -EINVAL;
fn = select_comparison_fn(pred->op, field->size,
field->is_signed);
if (!fn) {
parse_error(ps, FILT_ERR_INVALID_OP, 0);
return -EINVAL;
}
}
if (pred->op == OP_NE)
pred->not = 1;
return filter_add_pred_fn(ps, call, pred, fn);
add_pred_fn:
if (!dry_run)
return filter_add_pred_fn(ps, call, pred, fn);
return 0;
}
static int filter_add_subsystem_pred(struct filter_parse_state *ps,
struct event_subsystem *system,
struct filter_pred *pred,
char *filter_string)
char *filter_string,
bool dry_run)
{
struct ftrace_event_call *call;
int err = 0;
bool fail = true;
list_for_each_entry(call, &ftrace_events, list) {
......@@ -610,16 +631,24 @@ static int filter_add_subsystem_pred(struct filter_parse_state *ps,
if (strcmp(call->system, system->name))
continue;
err = filter_add_pred(ps, call, pred);
if (err) {
filter_free_subsystem_preds(system);
parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
goto out;
}
replace_filter_string(call->filter, filter_string);
if (call->filter->no_reset)
continue;
err = filter_add_pred(ps, call, pred, dry_run);
if (err)
call->filter->no_reset = true;
else
fail = false;
if (!dry_run)
replace_filter_string(call->filter, filter_string);
}
out:
return err;
if (fail) {
parse_error(ps, FILT_ERR_BAD_SUBSYS_FILTER, 0);
return err;
}
return 0;
}
static void parse_init(struct filter_parse_state *ps,
......@@ -978,12 +1007,14 @@ static int check_preds(struct filter_parse_state *ps)
static int replace_preds(struct event_subsystem *system,
struct ftrace_event_call *call,
struct filter_parse_state *ps,
char *filter_string)
char *filter_string,
bool dry_run)
{
char *operand1 = NULL, *operand2 = NULL;
struct filter_pred *pred;
struct postfix_elt *elt;
int err;
int n_preds = 0;
err = check_preds(ps);
if (err)
......@@ -1002,19 +1033,14 @@ static int replace_preds(struct event_subsystem *system,
continue;
}
if (n_preds++ == MAX_FILTER_PRED) {
parse_error(ps, FILT_ERR_TOO_MANY_PREDS, 0);
return -ENOSPC;
}
if (elt->op == OP_AND || elt->op == OP_OR) {
pred = create_logical_pred(elt->op);
if (call)
err = filter_add_pred(ps, call, pred);
else
err = filter_add_subsystem_pred(ps, system,
pred, filter_string);
filter_free_pred(pred);
if (err)
return err;
operand1 = operand2 = NULL;
continue;
goto add_pred;
}
if (!operand1 || !operand2) {
......@@ -1023,11 +1049,12 @@ static int replace_preds(struct event_subsystem *system,
}
pred = create_pred(elt->op, operand1, operand2);
add_pred:
if (call)
err = filter_add_pred(ps, call, pred);
err = filter_add_pred(ps, call, pred, false);
else
err = filter_add_subsystem_pred(ps, system, pred,
filter_string);
filter_string, dry_run);
filter_free_pred(pred);
if (err)
return err;
......@@ -1068,7 +1095,7 @@ int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
goto out;
}
err = replace_preds(NULL, call, ps, filter_string);
err = replace_preds(NULL, call, ps, filter_string, false);
if (err)
append_filter_err(ps, call->filter);
......@@ -1092,7 +1119,7 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
mutex_lock(&event_mutex);
if (!strcmp(strstrip(filter_string), "0")) {
filter_free_subsystem_preds(system);
filter_free_subsystem_preds(system, FILTER_DISABLE_ALL);
remove_filter_string(system->filter);
mutex_unlock(&event_mutex);
return 0;
......@@ -1103,7 +1130,6 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
if (!ps)
goto out_unlock;
filter_free_subsystem_preds(system);
replace_filter_string(system->filter, filter_string);
parse_init(ps, filter_ops, filter_string);
......@@ -1113,9 +1139,23 @@ int apply_subsystem_event_filter(struct event_subsystem *system,
goto out;
}
err = replace_preds(system, NULL, ps, filter_string);
if (err)
filter_free_subsystem_preds(system, FILTER_INIT_NO_RESET);
/* try to see the filter can be applied to which events */
err = replace_preds(system, NULL, ps, filter_string, true);
if (err) {
append_filter_err(ps, system->filter);
goto out;
}
filter_free_subsystem_preds(system, FILTER_SKIP_NO_RESET);
/* really apply the filter to the events */
err = replace_preds(system, NULL, ps, filter_string, false);
if (err) {
append_filter_err(ps, system->filter);
filter_free_subsystem_preds(system, 2);
}
out:
filter_opstack_clear(ps);
......
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