Author: Frederic Weisbecker <fweisbec@xxxxxxxxx>
AuthorDate: Thu, 19 Feb 2009 21:13:12 +0100
Commit: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Fri, 20 Feb 2009 11:36:24 +0100
tracing/function-graph-tracer: make set_graph_function file support ftrace regex
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@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/trace/ftrace.c | 56 +++++++++++++++++++++++++++++++++---------------
1 files changed, 38 insertions(+), 18 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 7dd5a2b..cf59f4c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -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, ¬);
+ 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;
--
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