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Date: Mon, 20 Jul 2009 10:20:53 +0800
From: Li Zefan <lizf@...fujitsu.com>
To: Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...e.hu>
CC: Steven Rostedt <rostedt@...dmis.org>,
Tom Zanussi <tzanussi@...il.com>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH v2] 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.
Inspied-by: Steven Rostedt <srostedt@...hat.com>
Signed-off-by: Li Zefan <lizf@...fujitsu.com>
---
include/linux/ftrace_event.h | 4 +-
kernel/trace/trace.h | 3 +-
kernel/trace/trace_events_filter.c | 124 ++++++++++++++++++++++++------------
3 files changed, 87 insertions(+), 44 deletions(-)
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 5c093ff..26d3673 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -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
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 06886a0..3a87d46 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -768,13 +768,14 @@ 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;
};
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index b9aae72..c7ed427 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -418,7 +418,14 @@ 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;
@@ -426,6 +433,14 @@ 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);
@@ -527,7 +542,8 @@ 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;
@@ -539,10 +555,12 @@ 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);
@@ -565,9 +583,6 @@ 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);
@@ -578,27 +593,33 @@ 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) {
@@ -608,16 +629,24 @@ 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,
@@ -976,12 +1005,14 @@ 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)
@@ -1000,19 +1031,14 @@ 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) {
@@ -1021,11 +1047,12 @@ 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;
@@ -1066,7 +1093,7 @@ 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);
@@ -1090,7 +1117,7 @@ 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;
@@ -1101,7 +1128,6 @@ 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);
@@ -1111,9 +1137,23 @@ 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);
--
1.6.3
--
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