tracing/profile: Add filter support
- Add an ioctl to allocate a filter for a perf event.
- Free the filter when the associated perf event is to be freed.
- Do the filtering in perf_swevent_match().
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4AD69546.8050401@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index ffe53dd..4959ada 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -743,7 +743,8 @@
struct ring_buffer *buffer,
struct ring_buffer_event *event)
{
- if (unlikely(call->filter_active) && !filter_match_preds(call, rec)) {
+ if (unlikely(call->filter_active) &&
+ !filter_match_preds(call->filter, rec)) {
ring_buffer_discard_commit(buffer, event);
return 1;
}
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 273845f..e27bb6a 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -21,6 +21,7 @@
#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/mutex.h>
+#include <linux/perf_event.h>
#include "trace.h"
#include "trace_output.h"
@@ -363,9 +364,8 @@
}
/* return 1 if event matches, 0 otherwise (discard) */
-int filter_match_preds(struct ftrace_event_call *call, void *rec)
+int filter_match_preds(struct event_filter *filter, void *rec)
{
- struct event_filter *filter = call->filter;
int match, top = 0, val1 = 0, val2 = 0;
int stack[MAX_FILTER_PRED];
struct filter_pred *pred;
@@ -538,9 +538,8 @@
filter->preds[i]->fn = filter_pred_none;
}
-void destroy_preds(struct ftrace_event_call *call)
+static void __free_preds(struct event_filter *filter)
{
- struct event_filter *filter = call->filter;
int i;
if (!filter)
@@ -553,21 +552,24 @@
kfree(filter->preds);
kfree(filter->filter_string);
kfree(filter);
- call->filter = NULL;
}
-static int init_preds(struct ftrace_event_call *call)
+void destroy_preds(struct ftrace_event_call *call)
+{
+ __free_preds(call->filter);
+ call->filter = NULL;
+ call->filter_active = 0;
+}
+
+static struct event_filter *__alloc_preds(void)
{
struct event_filter *filter;
struct filter_pred *pred;
int i;
- if (call->filter)
- return 0;
-
- filter = call->filter = kzalloc(sizeof(*filter), GFP_KERNEL);
- if (!call->filter)
- return -ENOMEM;
+ filter = kzalloc(sizeof(*filter), GFP_KERNEL);
+ if (!filter)
+ return ERR_PTR(-ENOMEM);
filter->n_preds = 0;
@@ -583,12 +585,24 @@
filter->preds[i] = pred;
}
- return 0;
+ return filter;
oom:
- destroy_preds(call);
+ __free_preds(filter);
+ return ERR_PTR(-ENOMEM);
+}
- return -ENOMEM;
+static int init_preds(struct ftrace_event_call *call)
+{
+ if (call->filter)
+ return 0;
+
+ call->filter_active = 0;
+ call->filter = __alloc_preds();
+ if (IS_ERR(call->filter))
+ return PTR_ERR(call->filter);
+
+ return 0;
}
static int init_subsystem_preds(struct event_subsystem *system)
@@ -629,10 +643,10 @@
static int filter_add_pred_fn(struct filter_parse_state *ps,
struct ftrace_event_call *call,
+ struct event_filter *filter,
struct filter_pred *pred,
filter_pred_fn_t fn)
{
- struct event_filter *filter = call->filter;
int idx, err;
if (filter->n_preds == MAX_FILTER_PRED) {
@@ -647,7 +661,6 @@
return err;
filter->n_preds++;
- call->filter_active = 1;
return 0;
}
@@ -726,6 +739,7 @@
static int filter_add_pred(struct filter_parse_state *ps,
struct ftrace_event_call *call,
+ struct event_filter *filter,
struct filter_pred *pred,
bool dry_run)
{
@@ -795,7 +809,7 @@
add_pred_fn:
if (!dry_run)
- return filter_add_pred_fn(ps, call, pred, fn);
+ return filter_add_pred_fn(ps, call, filter, pred, fn);
return 0;
}
@@ -1154,6 +1168,7 @@
}
static int replace_preds(struct ftrace_event_call *call,
+ struct event_filter *filter,
struct filter_parse_state *ps,
char *filter_string,
bool dry_run)
@@ -1200,7 +1215,7 @@
add_pred:
if (!pred)
return -ENOMEM;
- err = filter_add_pred(ps, call, pred, dry_run);
+ err = filter_add_pred(ps, call, filter, pred, dry_run);
filter_free_pred(pred);
if (err)
return err;
@@ -1216,6 +1231,7 @@
char *filter_string)
{
struct ftrace_event_call *call;
+ struct event_filter *filter;
int err;
bool fail = true;
@@ -1228,17 +1244,19 @@
continue;
/* try to see if the filter can be applied */
- err = replace_preds(call, ps, filter_string, true);
+ err = replace_preds(call, filter, ps, filter_string, true);
if (err)
continue;
/* really apply the filter */
filter_disable_preds(call);
- err = replace_preds(call, ps, filter_string, false);
+ err = replace_preds(call, filter, ps, filter_string, false);
if (err)
filter_disable_preds(call);
- else
- replace_filter_string(call->filter, filter_string);
+ else {
+ call->filter_active = 1;
+ replace_filter_string(filter, filter_string);
+ }
fail = false;
}
@@ -1252,7 +1270,6 @@
int apply_event_filter(struct ftrace_event_call *call, char *filter_string)
{
int err;
-
struct filter_parse_state *ps;
mutex_lock(&event_mutex);
@@ -1283,10 +1300,11 @@
goto out;
}
- err = replace_preds(call, ps, filter_string, false);
+ err = replace_preds(call, call->filter, ps, filter_string, false);
if (err)
append_filter_err(ps, call->filter);
-
+ else
+ call->filter_active = 1;
out:
filter_opstack_clear(ps);
postfix_clear(ps);
@@ -1301,7 +1319,6 @@
char *filter_string)
{
int err;
-
struct filter_parse_state *ps;
mutex_lock(&event_mutex);
@@ -1345,3 +1362,67 @@
return err;
}
+#ifdef CONFIG_EVENT_PROFILE
+
+void ftrace_profile_free_filter(struct perf_event *event)
+{
+ struct event_filter *filter = event->filter;
+
+ event->filter = NULL;
+ __free_preds(filter);
+}
+
+int ftrace_profile_set_filter(struct perf_event *event, int event_id,
+ char *filter_str)
+{
+ int err;
+ struct event_filter *filter;
+ struct filter_parse_state *ps;
+ struct ftrace_event_call *call = NULL;
+
+ mutex_lock(&event_mutex);
+
+ list_for_each_entry(call, &ftrace_events, list) {
+ if (call->id == event_id)
+ break;
+ }
+ if (!call)
+ return -EINVAL;
+
+ if (event->filter)
+ return -EEXIST;
+
+ filter = __alloc_preds();
+ if (IS_ERR(filter))
+ return PTR_ERR(filter);
+
+ err = -ENOMEM;
+ ps = kzalloc(sizeof(*ps), GFP_KERNEL);
+ if (!ps)
+ goto free_preds;
+
+ parse_init(ps, filter_ops, filter_str);
+ err = filter_parse(ps);
+ if (err)
+ goto free_ps;
+
+ err = replace_preds(call, filter, ps, filter_str, false);
+ if (!err)
+ event->filter = filter;
+
+free_ps:
+ filter_opstack_clear(ps);
+ postfix_clear(ps);
+ kfree(ps);
+
+free_preds:
+ if (err)
+ __free_preds(filter);
+
+ mutex_unlock(&event_mutex);
+
+ return err;
+}
+
+#endif /* CONFIG_EVENT_PROFILE */
+