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tracing: Add hist trigger support for stacktraces as keys

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It's often useful to be able to use a stacktrace as a hash key, for
keeping a count of the number of times a particular call path resulted
in a trace event, for instance.  Add a special key named 'stacktrace'
which can be used as key in a 'keys=' param for this purpose:

    # echo hist:keys=stacktrace ... \
               [ if filter] > event/trigger

Link: http://lkml.kernel.org/r/87515e90b3785232a874a12156174635a348edb1.1457029949.git.tom.zanussi@linux.intel.com

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Tom Zanussi
2016-03-03 12:54:52 -06:00
committed by Steven Rostedt
父節點 316961988b
當前提交 69a0200c2e
共有 2 個文件被更改，包括 109 次插入 和 42 次删除
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135
kernel/trace/trace_events_hist.c
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@@ -35,6 +35,11 @@ struct hist_field {
unsigned int offset;
};
static u64 hist_field_none(struct hist_field *field, void *event)
{
return 0;
}
static u64 hist_field_counter(struct hist_field *field, void *event)
{
return 1;
@@ -73,8 +78,12 @@ DEFINE_HIST_FIELD_FN(u8);
#define for_each_hist_key_field(i, hist_data) \
for ((i) = (hist_data)->n_vals; (i) < (hist_data)->n_fields; (i)++)
#define HIST_STACKTRACE_DEPTH 16
#define HIST_STACKTRACE_SIZE (HIST_STACKTRACE_DEPTH * sizeof(unsigned long))
#define HIST_STACKTRACE_SKIP 5
#define HITCOUNT_IDX 0
#define HIST_KEY_SIZE_MAX (MAX_FILTER_STR_VAL + sizeof(u64))
#define HIST_KEY_SIZE_MAX (MAX_FILTER_STR_VAL + HIST_STACKTRACE_SIZE)
enum hist_field_flags {
HIST_FIELD_FL_HITCOUNT = 1,
@@ -85,6 +94,7 @@ enum hist_field_flags {
HIST_FIELD_FL_SYM_OFFSET = 32,
HIST_FIELD_FL_EXECNAME = 64,
HIST_FIELD_FL_SYSCALL = 128,
HIST_FIELD_FL_STACKTRACE = 256,
};
struct hist_trigger_attrs {
@@ -323,6 +333,11 @@ static struct hist_field *create_hist_field(struct ftrace_event_field *field,
goto out;
}
if (flags & HIST_FIELD_FL_STACKTRACE) {
hist_field->fn = hist_field_none;
goto out;
}
if (is_string_field(field)) {
flags |= HIST_FIELD_FL_STRING;
hist_field->fn = hist_field_string;
@@ -456,7 +471,6 @@ static int create_key_field(struct hist_trigger_data *hist_data,
struct ftrace_event_field *field = NULL;
unsigned long flags = 0;
unsigned int key_size;
char *field_name;
int ret = 0;
if (WARN_ON(key_idx >= TRACING_MAP_FIELDS_MAX))
@@ -464,33 +478,39 @@ static int create_key_field(struct hist_trigger_data *hist_data,
flags |= HIST_FIELD_FL_KEY;
field_name = strsep(&field_str, ".");
if (field_str) {
if (strcmp(field_str, "hex") == 0)
flags |= HIST_FIELD_FL_HEX;
else if (strcmp(field_str, "sym") == 0)
flags |= HIST_FIELD_FL_SYM;
else if (strcmp(field_str, "sym-offset") == 0)
flags |= HIST_FIELD_FL_SYM_OFFSET;
else if ((strcmp(field_str, "execname") == 0) &&
(strcmp(field_name, "common_pid") == 0))
flags |= HIST_FIELD_FL_EXECNAME;
else if (strcmp(field_str, "syscall") == 0)
flags |= HIST_FIELD_FL_SYSCALL;
else {
if (strcmp(field_str, "stacktrace") == 0) {
flags |= HIST_FIELD_FL_STACKTRACE;
key_size = sizeof(unsigned long) * HIST_STACKTRACE_DEPTH;
} else {
char *field_name = strsep(&field_str, ".");
if (field_str) {
if (strcmp(field_str, "hex") == 0)
flags |= HIST_FIELD_FL_HEX;
else if (strcmp(field_str, "sym") == 0)
flags |= HIST_FIELD_FL_SYM;
else if (strcmp(field_str, "sym-offset") == 0)
flags |= HIST_FIELD_FL_SYM_OFFSET;
else if ((strcmp(field_str, "execname") == 0) &&
(strcmp(field_name, "common_pid") == 0))
flags |= HIST_FIELD_FL_EXECNAME;
else if (strcmp(field_str, "syscall") == 0)
flags |= HIST_FIELD_FL_SYSCALL;
else {
ret = -EINVAL;
goto out;
}
}
field = trace_find_event_field(file->event_call, field_name);
if (!field) {
ret = -EINVAL;
goto out;
}
}
field = trace_find_event_field(file->event_call, field_name);
if (!field) {
ret = -EINVAL;
goto out;
key_size = field->size;
}
key_size = field->size;
hist_data->fields[key_idx] = create_hist_field(field, flags);
if (!hist_data->fields[key_idx]) {
ret = -ENOMEM;
@@ -679,7 +699,9 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
field = hist_field->field;
if (is_string_field(field))
if (hist_field->flags & HIST_FIELD_FL_STACKTRACE)
cmp_fn = tracing_map_cmp_none;
else if (is_string_field(field))
cmp_fn = tracing_map_cmp_string;
else
cmp_fn = tracing_map_cmp_num(field->size,
@@ -786,7 +808,9 @@ static void hist_trigger_elt_update(struct hist_trigger_data *hist_data,
static void event_hist_trigger(struct event_trigger_data *data, void *rec)
{
struct hist_trigger_data *hist_data = data->private_data;
unsigned long entries[HIST_STACKTRACE_DEPTH];
char compound_key[HIST_KEY_SIZE_MAX];
struct stack_trace stacktrace;
struct hist_field *key_field;
struct tracing_map_elt *elt;
u64 field_contents;
@@ -799,15 +823,27 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec)
for_each_hist_key_field(i, hist_data) {
key_field = hist_data->fields[i];
field_contents = key_field->fn(key_field, rec);
if (key_field->flags & HIST_FIELD_FL_STRING)
key = (void *)(unsigned long)field_contents;
else
key = (void *)&field_contents;
if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
stacktrace.max_entries = HIST_STACKTRACE_DEPTH;
stacktrace.entries = entries;
stacktrace.nr_entries = 0;
stacktrace.skip = HIST_STACKTRACE_SKIP;
if (hist_data->n_keys > 1) {
memcpy(compound_key + key_field->offset, key,
key_field->size);
memset(stacktrace.entries, 0, HIST_STACKTRACE_SIZE);
save_stack_trace(&stacktrace);
key = entries;
} else {
field_contents = key_field->fn(key_field, rec);
if (key_field->flags & HIST_FIELD_FL_STRING)
key = (void *)(unsigned long)field_contents;
else
key = (void *)&field_contents;
if (hist_data->n_keys > 1) {
memcpy(compound_key + key_field->offset, key,
key_field->size);
}
}
}
@@ -819,6 +855,24 @@ static void event_hist_trigger(struct event_trigger_data *data, void *rec)
hist_trigger_elt_update(hist_data, elt, rec);
}
static void hist_trigger_stacktrace_print(struct seq_file *m,
unsigned long *stacktrace_entries,
unsigned int max_entries)
{
char str[KSYM_SYMBOL_LEN];
unsigned int spaces = 8;
unsigned int i;
for (i = 0; i < max_entries; i++) {
if (stacktrace_entries[i] == ULONG_MAX)
return;
seq_printf(m, "%*c", 1 + spaces, ' ');
sprint_symbol(str, stacktrace_entries[i]);
seq_printf(m, "%s\n", str);
}
}
static void
hist_trigger_entry_print(struct seq_file *m,
struct hist_trigger_data *hist_data, void *key,
@@ -826,6 +880,7 @@ hist_trigger_entry_print(struct seq_file *m,
{
struct hist_field *key_field;
char str[KSYM_SYMBOL_LEN];
bool multiline = false;
unsigned int i;
u64 uval;
@@ -867,6 +922,12 @@ hist_trigger_entry_print(struct seq_file *m,
seq_printf(m, "%s: %-30s[%3llu]",
key_field->field->name, syscall_name, uval);
} else if (key_field->flags & HIST_FIELD_FL_STACKTRACE) {
seq_puts(m, "stacktrace:\n");
hist_trigger_stacktrace_print(m,
key + key_field->offset,
HIST_STACKTRACE_DEPTH);
multiline = true;
} else if (key_field->flags & HIST_FIELD_FL_STRING) {
seq_printf(m, "%s: %-50s", key_field->field->name,
(char *)(key + key_field->offset));
@@ -877,7 +938,10 @@ hist_trigger_entry_print(struct seq_file *m,
}
}
seq_puts(m, " }");
if (!multiline)
seq_puts(m, " ");
seq_puts(m, "}");
seq_printf(m, " hitcount: %10llu",
tracing_map_read_sum(elt, HITCOUNT_IDX));
@@ -1021,7 +1085,10 @@ static int event_hist_trigger_print(struct seq_file *m,
if (i > hist_data->n_vals)
seq_puts(m, ",");
hist_field_print(m, key_field);
if (key_field->flags & HIST_FIELD_FL_STACKTRACE)
seq_puts(m, "stacktrace");
else
hist_field_print(m, key_field);
}
seq_puts(m, ":vals=");