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authorSteven Rostedt <srostedt@redhat.com>2009-05-28 13:37:24 -0400
committerSteven Rostedt <rostedt@goodmis.org>2009-06-01 23:23:10 -0400
commit2af15d6a44b871ad4c2a651302374cde8f335480 (patch)
tree39f06d511e3e1d1970fe4571128549c1c26230c1 /kernel/trace
parentf2aebaee653a35b01c3665de2cbb1e31456b8ea8 (diff)
ftrace: add kernel command line function filtering
When using ftrace=function on the command line to trace functions on boot up, one can not filter out functions that are commonly called. This patch adds two new ftrace command line commands. ftrace_notrace=function-list ftrace_filter=function-list Where function-list is a comma separated list of functions to filter. The ftrace_notrace will make the functions listed not be included in the function tracing, and ftrace_filter will only trace the functions listed. These two act the same as the debugfs/tracing/set_ftrace_notrace and debugfs/tracing/set_ftrace_filter respectively. The simple glob expressions that are allowed by the filter files can also be used by the command line interface. ftrace_notrace=rcu*,*lock,*spin* Will not trace any function that starts with rcu, ends with lock, or has the word spin in it. Note, if the self tests are enabled, they may interfere with the filtering set by the command lines. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ftrace.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 140699a9a8a..2074e5b7766 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -32,6 +32,7 @@
#include <trace/events/sched.h>
#include <asm/ftrace.h>
+#include <asm/setup.h>
#include "trace_output.h"
#include "trace_stat.h"
@@ -2369,6 +2370,45 @@ void ftrace_set_notrace(unsigned char *buf, int len, int reset)
ftrace_set_regex(buf, len, reset, 0);
}
+/*
+ * command line interface to allow users to set filters on boot up.
+ */
+#define FTRACE_FILTER_SIZE COMMAND_LINE_SIZE
+static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
+static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
+
+static int __init set_ftrace_notrace(char *str)
+{
+ strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
+ return 1;
+}
+__setup("ftrace_notrace=", set_ftrace_notrace);
+
+static int __init set_ftrace_filter(char *str)
+{
+ strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
+ return 1;
+}
+__setup("ftrace_filter=", set_ftrace_filter);
+
+static void __init set_ftrace_early_filter(char *buf, int enable)
+{
+ char *func;
+
+ while (buf) {
+ func = strsep(&buf, ",");
+ ftrace_set_regex(func, strlen(func), 0, enable);
+ }
+}
+
+static void __init set_ftrace_early_filters(void)
+{
+ if (ftrace_filter_buf[0])
+ set_ftrace_early_filter(ftrace_filter_buf, 1);
+ if (ftrace_notrace_buf[0])
+ set_ftrace_early_filter(ftrace_notrace_buf, 0);
+}
+
static int
ftrace_regex_release(struct inode *inode, struct file *file, int enable)
{
@@ -2829,6 +2869,8 @@ void __init ftrace_init(void)
if (ret)
pr_warning("Failed to register trace ftrace module notifier\n");
+ set_ftrace_early_filters();
+
return;
failed:
ftrace_disabled = 1;