[PATCH 7/7] ftrace, perf: Add filter support for function trace event
From: Jiri Olsa
Date: Wed Jan 18 2012 - 13:45:14 EST
Adding support to filter function trace event via perf
interface. It is now possible to use filter interface
in the perf tool like:
perf record -e ftrace:function --filter="(ip == mm_*)" ls
The filter syntax is restricted to the the 'ip' field only,
and following operators are accepted '==' '!=' '||', ending
up with the filter strings like:
ip == f1[, ]f2 ... || ip != f3[, ]f4 ...
with comma ',' or space ' ' as a function separator. If the
space ' ' is used as a separator, the right side of the
assignment needs to be enclosed in double quotes '"'.
The '==' operator adds trace filter with same effect as would
be added via set_ftrace_filter file.
The '!=' operator adds trace filter with same effect as would
be added via set_ftrace_notrace file.
The right side of the '!=', '==' operators is list of functions
or regexp. to be added to filter separated by space.
The '||' operator is used for connecting multiple filter definitions
together. It is possible to have more than one '==' and '!='
operators within one filter string.
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
include/linux/ftrace.h | 1 +
kernel/trace/ftrace.c | 6 ++
kernel/trace/trace.h | 2 -
kernel/trace/trace_event_perf.c | 4 +-
kernel/trace/trace_events_filter.c | 169 +++++++++++++++++++++++++++++++++---
5 files changed, 168 insertions(+), 14 deletions(-)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index d3f529c..60781ab 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -240,6 +240,7 @@ int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
int len, int reset);
void ftrace_set_global_filter(unsigned char *buf, int len, int reset);
void ftrace_set_global_notrace(unsigned char *buf, int len, int reset);
+void ftrace_free_filter(struct ftrace_ops *ops);
int register_ftrace_command(struct ftrace_func_command *cmd);
int unregister_ftrace_command(struct ftrace_func_command *cmd);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 45c9b0c..9935a2a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1192,6 +1192,12 @@ static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
}
+void ftrace_free_filter(struct ftrace_ops *ops)
+{
+ free_ftrace_hash(ops->filter_hash);
+ free_ftrace_hash(ops->notrace_hash);
+}
+
static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
{
struct ftrace_hash *hash;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index e88e58a..4ec6d18 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -770,9 +770,7 @@ struct filter_pred {
u64 val;
struct regex regex;
unsigned short *ops;
-#ifdef CONFIG_FTRACE_STARTUP_TEST
struct ftrace_event_field *field;
-#endif
int offset;
int not;
int op;
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 57eb232..220b50a 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -298,7 +298,9 @@ static int perf_ftrace_function_register(struct perf_event *event)
static int perf_ftrace_function_unregister(struct perf_event *event)
{
struct ftrace_ops *ops = &event->ftrace_ops;
- return unregister_ftrace_function(ops);
+ int ret = unregister_ftrace_function(ops);
+ ftrace_free_filter(ops);
+ return ret;
}
static void perf_ftrace_function_enable(struct perf_event *event)
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index eb04a2a..c8a64ec 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -54,6 +54,13 @@ struct filter_op {
int precedence;
};
+static struct filter_op filter_ftrace_ops[] = {
+ { OP_OR, "||", 1 },
+ { OP_NE, "!=", 2 },
+ { OP_EQ, "==", 2 },
+ { OP_NONE, "OP_NONE", 0 },
+};
+
static struct filter_op filter_ops[] = {
{ OP_OR, "||", 1 },
{ OP_AND, "&&", 2 },
@@ -81,6 +88,7 @@ enum {
FILT_ERR_TOO_MANY_PREDS,
FILT_ERR_MISSING_FIELD,
FILT_ERR_INVALID_FILTER,
+ FILT_ERR_IP_FIELD_ONLY,
};
static char *err_text[] = {
@@ -96,6 +104,7 @@ static char *err_text[] = {
"Too many terms in predicate expression",
"Missing field name and/or value",
"Meaningless filter expression",
+ "Only 'ip' field is supported for function trace",
};
struct opstack_op {
@@ -992,7 +1001,12 @@ static int init_pred(struct filter_parse_state *ps,
fn = filter_pred_strloc;
else
fn = filter_pred_pchar;
- } else if (!is_function_field(field)) {
+ } else if (is_function_field(field)) {
+ if (strcmp(field->name, "ip")) {
+ parse_error(ps, FILT_ERR_IP_FIELD_ONLY, 0);
+ return -EINVAL;
+ }
+ } else {
if (field->is_signed)
ret = strict_strtoll(pred->regex.pattern, 0, &val);
else
@@ -1339,10 +1353,7 @@ static struct filter_pred *create_pred(struct filter_parse_state *ps,
strcpy(pred.regex.pattern, operand2);
pred.regex.len = strlen(pred.regex.pattern);
-
-#ifdef CONFIG_FTRACE_STARTUP_TEST
pred.field = field;
-#endif
return init_pred(ps, field, &pred) ? NULL : &pred;
}
@@ -1743,8 +1754,8 @@ static int replace_system_preds(struct event_subsystem *system,
return -ENOMEM;
}
-static int create_filter_start(char *filter_str, bool set_str,
- struct filter_parse_state **psp,
+static int create_filter_start(char *filter_str, struct filter_op *fops,
+ bool set_str, struct filter_parse_state **psp,
struct event_filter **filterp)
{
struct event_filter *filter;
@@ -1770,7 +1781,7 @@ static int create_filter_start(char *filter_str, bool set_str,
*filterp = filter;
*psp = ps;
- parse_init(ps, filter_ops, filter_str);
+ parse_init(ps, fops, filter_str);
err = filter_parse(ps);
if (err && set_str)
append_filter_err(ps, filter);
@@ -1808,9 +1819,13 @@ static int create_filter(struct ftrace_event_call *call,
{
struct event_filter *filter = NULL;
struct filter_parse_state *ps = NULL;
+ struct filter_op *fops = filter_ops;
int err;
- err = create_filter_start(filter_str, set_str, &ps, &filter);
+ if (ftrace_event_is_function(call))
+ fops = filter_ftrace_ops;
+
+ err = create_filter_start(filter_str, fops, set_str, &ps, &filter);
if (!err) {
err = replace_preds(call, filter, ps, filter_str, false);
if (err && set_str)
@@ -1838,7 +1853,7 @@ static int create_system_filter(struct event_subsystem *system,
struct filter_parse_state *ps = NULL;
int err;
- err = create_filter_start(filter_str, true, &ps, &filter);
+ err = create_filter_start(filter_str, filter_ops, true, &ps, &filter);
if (!err) {
err = replace_system_preds(system, ps, filter_str);
if (!err) {
@@ -1955,6 +1970,131 @@ void ftrace_profile_free_filter(struct perf_event *event)
__free_filter(filter);
}
+struct function_filter_data {
+ struct ftrace_ops *ops;
+ int first_filter;
+ int first_notrace;
+};
+
+static char **
+ftrace_function_filter_re(char *buf, int len, int *count)
+{
+ char *str, *sep, **re;
+
+ str = kstrndup(buf, len, GFP_KERNEL);
+ if (!str)
+ return NULL;
+
+ /*
+ * The argv_split function takes white space
+ * as a separator, so convert ',' into spaces.
+ */
+ while ((sep = strchr(str, ',')))
+ *sep = ' ';
+
+ re = argv_split(GFP_KERNEL, str, count);
+ kfree(str);
+ return re;
+}
+
+static int ftrace_function_set_regexp(struct ftrace_ops *ops, int filter,
+ int reset, char *re, int len)
+{
+ int ret;
+
+ if (filter)
+ ret = ftrace_set_filter(ops, re, len, reset);
+ else
+ ret = ftrace_set_notrace(ops, re, len, reset);
+
+ return ret;
+}
+
+static int __ftrace_function_set_filter(int filter, char *buf, int len,
+ struct function_filter_data *data)
+{
+ int i, re_cnt, ret;
+ int *reset;
+ char **re;
+
+ reset = filter ? &data->first_filter : &data->first_notrace;
+
+ /*
+ * The 'ip' field could have multiple filters set, separated
+ * either by space or comma. We first cut the filter and apply
+ * all pieces separatelly.
+ */
+ re = ftrace_function_filter_re(buf, len, &re_cnt);
+ if (!re)
+ return -EINVAL;
+
+ for (i = 0; i < re_cnt; i++) {
+ ret = ftrace_function_set_regexp(data->ops, filter, *reset,
+ re[i], strlen(re[i]));
+ if (ret)
+ break;
+
+ if (*reset)
+ *reset = 0;
+ }
+
+ argv_free(re);
+ return ret;
+}
+
+static int ftrace_function_check_pred(struct filter_pred *pred)
+{
+ struct ftrace_event_field *field = pred->field;
+
+ /*
+ * Check the predicate for function trace, verify:
+ * - only '==' and '!=' is used
+ * - the 'ip' field is used
+ */
+ if (WARN((pred->op != OP_EQ) && (pred->op != OP_NE),
+ "wrong operator for function filter: %d\n", pred->op))
+ return -EINVAL;
+
+ if (strcmp(field->name, "ip"))
+ return -EINVAL;
+
+ return 0;
+}
+
+static int ftrace_function_set_filter_cb(enum move_type move,
+ struct filter_pred *pred,
+ int *err, void *data)
+{
+ if ((move != MOVE_DOWN) ||
+ (pred->left != FILTER_PRED_INVALID))
+ return WALK_PRED_DEFAULT;
+
+ /* Double checking the predicate is valid for function trace. */
+ *err = ftrace_function_check_pred(pred);
+ if (*err)
+ return WALK_PRED_ABORT;
+
+ *err = __ftrace_function_set_filter(pred->op == OP_EQ,
+ pred->regex.pattern,
+ pred->regex.len,
+ data);
+
+ return (*err) ? WALK_PRED_ABORT : WALK_PRED_DEFAULT;
+}
+
+static int ftrace_function_set_filter(struct perf_event *event,
+ struct event_filter *filter)
+{
+ struct function_filter_data data = {
+ .first_filter = 1,
+ .first_notrace = 1,
+ .ops = &event->ftrace_ops,
+ };
+
+ return walk_pred_tree(filter->preds, filter->root,
+ ftrace_function_set_filter_cb, &data);
+}
+
int ftrace_profile_set_filter(struct perf_event *event, int event_id,
char *filter_str)
{
@@ -1975,9 +2115,16 @@ int ftrace_profile_set_filter(struct perf_event *event, int event_id,
goto out_unlock;
err = create_filter(call, filter_str, false, &filter);
- if (!err)
- event->filter = filter;
+ if (err)
+ goto free_filter;
+
+ if (ftrace_event_is_function(call))
+ err = ftrace_function_set_filter(event, filter);
else
+ event->filter = filter;
+
+free_filter:
+ if (err || ftrace_event_is_function(call))
__free_filter(filter);
out_unlock:
--
1.7.1
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