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tracing/function-graph-tracer: make set_graph_function file support ftrace regex

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Impact: trace only functions matching a pattern

The set_graph_function file let one to trace only one or several
chosen functions and follow all their code flow.

Currently, only a constant function name is allowed so this patch
allows the ftrace_regex functions:

- matches all functions that end with "name":
  echo *name > set_graph_function

- matches all functions that begin with "name":
  echo name* > set_graph_function

- matches all functions that contains "name":
  echo *name* > set_graph_function

Example:

echo mutex* > set_graph_function

 0)               |  mutex_lock_nested() {
 0)   0.563 us    |    __might_sleep();
 0)   2.072 us    |  }
 0)               |  mutex_unlock() {
 0)   1.036 us    |    __mutex_unlock_slowpath();
 0)   2.433 us    |  }
 0)               |  mutex_unlock() {
 0)   0.691 us    |    __mutex_unlock_slowpath();
 0)   1.787 us    |  }
 0)               |  mutex_lock_interruptible_nested() {
 0)   0.548 us    |    __might_sleep();
 0)   1.945 us    |  }

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Frederic Weisbecker 2009-02-19 21:13:12 +01:00 committed by Ingo Molnar
parent 64b36ca7f4
commit f9349a8f97
1 changed files with 38 additions and 18 deletions
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56
kernel/trace/ftrace.c
View File

@ -1895,6 +1895,10 @@ static void *g_start(struct seq_file *m, loff_t *pos)
mutex_lock(&graph_lock);
/* Nothing, tell g_show to print all functions are enabled */
if (!ftrace_graph_count && !*pos)
return (void *)1;
p = g_next(m, p, pos);
return p;
@ -1913,6 +1917,11 @@ static int g_show(struct seq_file *m, void *v)
if (!ptr)
return 0;
if (ptr == (unsigned long *)1) {
seq_printf(m, "#### all functions enabled ####\n");
return 0;
}
kallsyms_lookup(*ptr, NULL, NULL, NULL, str);
seq_printf(m, "%s\n", str);
@ -1966,38 +1975,51 @@ ftrace_graph_read(struct file *file, char __user *ubuf,
}
static int
ftrace_set_func(unsigned long *array, int idx, char *buffer)
ftrace_set_func(unsigned long *array, int *idx, char *buffer)
{
char str[KSYM_SYMBOL_LEN];
struct dyn_ftrace *rec;
struct ftrace_page *pg;
int search_len;
int found = 0;
int j;
int type, not;
char *search;
bool exists;
int i;
if (ftrace_disabled)
return -ENODEV;
/* decode regex */
type = ftrace_setup_glob(buffer, strlen(buffer), &search, &not);
if (not)
return -EINVAL;
search_len = strlen(search);
mutex_lock(&ftrace_lock);
do_for_each_ftrace_rec(pg, rec) {
if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
break;
if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
continue;
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
if (strcmp(str, buffer) == 0) {
/* Return 1 if we add it to the array */
found = 1;
for (j = 0; j < idx; j++)
if (array[j] == rec->ip) {
found = 0;
if (ftrace_match_record(rec, search, search_len, type)) {
/* ensure it is not already in the array */
exists = false;
for (i = 0; i < *idx; i++)
if (array[i] == rec->ip) {
exists = true;
break;
}
if (found)
array[idx] = rec->ip;
goto out;
if (!exists) {
array[(*idx)++] = rec->ip;
found = 1;
}
}
} while_for_each_ftrace_rec();
out:
mutex_unlock(&ftrace_lock);
return found ? 0 : -EINVAL;
@ -2066,13 +2088,11 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
}
buffer[index] = 0;
/* we allow only one at a time */
ret = ftrace_set_func(array, ftrace_graph_count, buffer);
/* we allow only one expression at a time */
ret = ftrace_set_func(array, &ftrace_graph_count, buffer);
if (ret)
goto out;
ftrace_graph_count++;
file->f_pos += read;
ret = read;