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tracing/filters: move preds into event_filter object
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Create a new event_filter object, and move the pred-related members
out of the call and subsystem objects and into the filter object - the
details of the filter implementation don't need to be exposed in the
call and subsystem in any case, and it will also help make the new
parser implementation a little cleaner.

[ Impact: refactor trace-filter code to prepare for new features ]

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: fweisbec@gmail.com
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <1240905887.6416.119.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Tom Zanussi authored and Ingo Molnar committed Apr 29, 2009
1 parent 0f9a623 commit 30e673b
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Showing 4 changed files with 76 additions and 48 deletions.
4 changes: 2 additions & 2 deletions include/linux/ftrace_event.h
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Original file line number Diff line number Diff line change
Expand Up @@ -101,8 +101,8 @@ struct ftrace_event_call {
int (*show_format)(struct trace_seq *s);
int (*define_fields)(void);
struct list_head fields;
int n_preds;
struct filter_pred **preds;
int filter_active;
void *filter;
void *mod;

#ifdef CONFIG_EVENT_PROFILE
Expand Down
10 changes: 7 additions & 3 deletions kernel/trace/trace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -731,12 +731,16 @@ struct ftrace_event_field {
int size;
};

struct event_filter {
int n_preds;
struct filter_pred **preds;
};

struct event_subsystem {
struct list_head list;
const char *name;
struct dentry *entry;
int n_preds;
struct filter_pred **preds;
void *filter;
};

struct filter_pred;
Expand Down Expand Up @@ -774,7 +778,7 @@ filter_check_discard(struct ftrace_event_call *call, void *rec,
struct ring_buffer *buffer,
struct ring_buffer_event *event)
{
if (unlikely(call->n_preds) && !filter_match_preds(call, rec)) {
if (unlikely(call->filter_active) && !filter_match_preds(call, rec)) {
ring_buffer_discard_commit(buffer, event);
return 1;
}
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3 changes: 1 addition & 2 deletions kernel/trace/trace_events.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -757,8 +757,7 @@ event_subsystem_dir(const char *name, struct dentry *d_events)

list_add(&system->list, &event_subsystems);

system->preds = NULL;
system->n_preds = 0;
system->filter = NULL;

entry = debugfs_create_file("filter", 0644, system->entry, system,
&ftrace_subsystem_filter_fops);
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107 changes: 66 additions & 41 deletions kernel/trace/trace_events_filter.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -93,11 +93,12 @@ static int filter_pred_none(struct filter_pred *pred, void *event)
/* return 1 if event matches, 0 otherwise (discard) */
int filter_match_preds(struct ftrace_event_call *call, void *rec)
{
struct event_filter *filter = call->filter;
int i, matched, and_failed = 0;
struct filter_pred *pred;

for (i = 0; i < call->n_preds; i++) {
pred = call->preds[i];
for (i = 0; i < filter->n_preds; i++) {
pred = filter->preds[i];
if (and_failed && !pred->or)
continue;
matched = pred->fn(pred, rec);
Expand All @@ -115,20 +116,20 @@ int filter_match_preds(struct ftrace_event_call *call, void *rec)
}
EXPORT_SYMBOL_GPL(filter_match_preds);

static void __filter_print_preds(struct filter_pred **preds, int n_preds,
static void __filter_print_preds(struct event_filter *filter,
struct trace_seq *s)
{
char *field_name;
struct filter_pred *pred;
char *field_name;
int i;

if (!n_preds) {
if (!filter || !filter->n_preds) {
trace_seq_printf(s, "none\n");
return;
}

for (i = 0; i < n_preds; i++) {
pred = preds[i];
for (i = 0; i < filter->n_preds; i++) {
pred = filter->preds[i];
field_name = pred->field_name;
if (i)
trace_seq_printf(s, pred->or ? "|| " : "&& ");
Expand All @@ -144,15 +145,15 @@ static void __filter_print_preds(struct filter_pred **preds, int n_preds,
void filter_print_preds(struct ftrace_event_call *call, struct trace_seq *s)
{
mutex_lock(&filter_mutex);
__filter_print_preds(call->preds, call->n_preds, s);
__filter_print_preds(call->filter, s);
mutex_unlock(&filter_mutex);
}

void filter_print_subsystem_preds(struct event_subsystem *system,
struct trace_seq *s)
{
mutex_lock(&filter_mutex);
__filter_print_preds(system->preds, system->n_preds, s);
__filter_print_preds(system->filter, s);
mutex_unlock(&filter_mutex);
}

Expand Down Expand Up @@ -200,12 +201,14 @@ static int filter_set_pred(struct filter_pred *dest,

static void __filter_disable_preds(struct ftrace_event_call *call)
{
struct event_filter *filter = call->filter;
int i;

call->n_preds = 0;
call->filter_active = 0;
filter->n_preds = 0;

for (i = 0; i < MAX_FILTER_PRED; i++)
call->preds[i]->fn = filter_pred_none;
filter->preds[i]->fn = filter_pred_none;
}

void filter_disable_preds(struct ftrace_event_call *call)
Expand All @@ -217,48 +220,56 @@ void filter_disable_preds(struct ftrace_event_call *call)

int init_preds(struct ftrace_event_call *call)
{
struct event_filter *filter;
struct filter_pred *pred;
int i;

call->n_preds = 0;

call->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred), GFP_KERNEL);
if (!call->preds)
filter = call->filter = kzalloc(sizeof(*filter), GFP_KERNEL);
if (!call->filter)
return -ENOMEM;

call->filter_active = 0;
filter->n_preds = 0;

filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred), GFP_KERNEL);
if (!filter->preds)
goto oom;

for (i = 0; i < MAX_FILTER_PRED; i++) {
pred = kzalloc(sizeof(*pred), GFP_KERNEL);
if (!pred)
goto oom;
pred->fn = filter_pred_none;
call->preds[i] = pred;
filter->preds[i] = pred;
}

return 0;

oom:
for (i = 0; i < MAX_FILTER_PRED; i++) {
if (call->preds[i])
filter_free_pred(call->preds[i]);
if (filter->preds[i])
filter_free_pred(filter->preds[i]);
}
kfree(call->preds);
call->preds = NULL;
kfree(filter->preds);
kfree(call->filter);
call->filter = NULL;

return -ENOMEM;
}
EXPORT_SYMBOL_GPL(init_preds);

static void __filter_free_subsystem_preds(struct event_subsystem *system)
{
struct event_filter *filter = system->filter;
struct ftrace_event_call *call;
int i;

if (system->n_preds) {
for (i = 0; i < system->n_preds; i++)
filter_free_pred(system->preds[i]);
kfree(system->preds);
system->preds = NULL;
system->n_preds = 0;
if (filter && filter->n_preds) {
for (i = 0; i < filter->n_preds; i++)
filter_free_pred(filter->preds[i]);
kfree(filter->preds);
kfree(filter);
system->filter = NULL;
}

list_for_each_entry(call, &ftrace_events, list) {
Expand All @@ -281,21 +292,23 @@ static int filter_add_pred_fn(struct ftrace_event_call *call,
struct filter_pred *pred,
filter_pred_fn_t fn)
{
struct event_filter *filter = call->filter;
int idx, err;

if (call->n_preds && !pred->compound)
if (filter->n_preds && !pred->compound)
__filter_disable_preds(call);

if (call->n_preds == MAX_FILTER_PRED)
if (filter->n_preds == MAX_FILTER_PRED)
return -ENOSPC;

idx = call->n_preds;
filter_clear_pred(call->preds[idx]);
err = filter_set_pred(call->preds[idx], pred, fn);
idx = filter->n_preds;
filter_clear_pred(filter->preds[idx]);
err = filter_set_pred(filter->preds[idx], pred, fn);
if (err)
return err;

call->n_preds++;
filter->n_preds++;
call->filter_active = 1;

return 0;
}
Expand Down Expand Up @@ -366,29 +379,41 @@ int filter_add_pred(struct ftrace_event_call *call, struct filter_pred *pred)
int filter_add_subsystem_pred(struct event_subsystem *system,
struct filter_pred *pred)
{
struct event_filter *filter = system->filter;
struct ftrace_event_call *call;

mutex_lock(&filter_mutex);

if (system->n_preds && !pred->compound)
if (filter && filter->n_preds && !pred->compound) {
__filter_free_subsystem_preds(system);
filter = NULL;
}

if (!system->n_preds) {
system->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred),
if (!filter) {
system->filter = kzalloc(sizeof(*filter), GFP_KERNEL);
if (!system->filter) {
mutex_unlock(&filter_mutex);
return -ENOMEM;
}
filter = system->filter;
filter->preds = kzalloc(MAX_FILTER_PRED * sizeof(pred),
GFP_KERNEL);
if (!system->preds) {

if (!filter->preds) {
kfree(system->filter);
system->filter = NULL;
mutex_unlock(&filter_mutex);
return -ENOMEM;
}
}

if (system->n_preds == MAX_FILTER_PRED) {
if (filter->n_preds == MAX_FILTER_PRED) {
mutex_unlock(&filter_mutex);
return -ENOSPC;
}

system->preds[system->n_preds] = pred;
system->n_preds++;
filter->preds[filter->n_preds] = pred;
filter->n_preds++;

list_for_each_entry(call, &ftrace_events, list) {
int err;
Expand All @@ -401,8 +426,8 @@ int filter_add_subsystem_pred(struct event_subsystem *system,

err = __filter_add_pred(call, pred);
if (err == -ENOMEM) {
system->preds[system->n_preds] = NULL;
system->n_preds--;
filter->preds[filter->n_preds] = NULL;
filter->n_preds--;
mutex_unlock(&filter_mutex);
return err;
}
Expand Down

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