[RFC][PATCH v1 13/15] perf: export tracepoint events via sysfs: ext4, jbd2, xfs, gfs2

[Lin Ming <ming.m.lin@intel.com>]

ext4, jbd2, xfs, gfs2 tracepoint events are exported like below,

/sys/fs/events/
|-- ext4_alloc_da_blocks
|   |-- config
|   `-- type
....
....
|-- jbd2_checkpoint
|   |-- config
|   `-- type
....
....
|-- xfs_agf
|   |-- config
|   `-- type
....
....
|-- gfs2_block_alloc
|   |-- config
|   `-- type
....
....
---
 fs/namespace.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index 88058de..b4bc3dd 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -29,6 +29,7 @@
 #include <linux/log2.h>
 #include <linux/idr.h>
 #include <linux/fs_struct.h>
+#include <linux/perf_event.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 #include "pnode.h"
@@ -2305,6 +2306,20 @@ static void __init init_mount_tree(void)
 	set_fs_root(current->fs, &root);
 }
 
+static void fs_sys_add_tp(struct kobject *kobj)
+{
+	struct kobject *events_kobj;
+
+	events_kobj = perf_sys_create_events_dir(kobj);
+	if (events_kobj)
+		return;
+
+	perf_sys_add_tp_events(events_kobj, "ext4");
+	perf_sys_add_tp_events(events_kobj, "jbd2");
+	perf_sys_add_tp_events(events_kobj, "xfs");
+	perf_sys_add_tp_events(events_kobj, "gfs2");
+}
+
 void __init mnt_init(void)
 {
 	unsigned u;
@@ -2332,6 +2347,8 @@ void __init mnt_init(void)
 	fs_kobj = kobject_create_and_add("fs", NULL);
 	if (!fs_kobj)
 		printk(KERN_WARNING "%s: kobj create error\n", __func__);
+	else
+		fs_sys_add_tp(fs_kobj);
 	init_rootfs();
 	init_mount_tree();
 }