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Re: CONFIG_RELAY and debugfs in SystemTap
- From: Tom Zanussi <zanussi at us dot ibm dot com>
- To: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- Cc: Tom Zanussi <zanussi at us dot ibm dot com>, systemtap at sources dot redhat dot com
- Date: Thu, 14 Sep 2006 08:26:19 -0500
- Subject: Re: CONFIG_RELAY and debugfs in SystemTap
- References: <17671.7993.350107.336401@tut.ibm.com> <4508C4BB.90203@hitachi.com>
Masami Hiramatsu writes:
> Hi Tom,
>
> Could you show me an actual patch of this change?
> I'm interested in it.
>
Here's the patch. It works for me, but I still need to do some
testing on it, which I probably won't get to by the end of the week.
If you could take it for a spin and report problems if you see any,
that would be great.
Tom
Index: README
===================================================================
RCS file: /cvs/systemtap/src/README,v
retrieving revision 1.16
diff -u -p -r1.16 README
--- README 14 Jun 2006 15:14:30 -0000 1.16
+++ README 14 Sep 2006 13:14:19 -0000
@@ -53,7 +53,8 @@ Tips:
Building a kernel.org kernel:
- Build the kernel using your normal procedures. Enable
- CONFIG_DEBUG_INFO, CONFIG_KPROBES, and optionally CONFIG_RELAY.
+ CONFIG_DEBUG_INFO, CONFIG_KPROBES, and optionally CONFIG_RELAY and
+ CONFIG_DEBUG_FS.
- Boot into the kernel.
- Make sure the large unstripped kernel image 'vmlinux' from your
build can be found by systemtap (see above) You can just symlink
Index: runtime/stpd/stpd.c
===================================================================
RCS file: /cvs/systemtap/src/runtime/stpd/stpd.c,v
retrieving revision 1.23
diff -u -p -r1.23 stpd.c
--- runtime/stpd/stpd.c 2 Aug 2006 14:06:35 -0000 1.23
+++ runtime/stpd/stpd.c 14 Sep 2006 13:14:20 -0000
@@ -54,6 +54,7 @@ gid_t cmd_gid;
/* relayfs base file name */
static char stpd_filebase[1024];
#define RELAYFS_MAGIC 0xF0B4A981
+#define DEBUGFS_MAGIC 0x64626720
/* stp_check script */
#ifdef PKGLIBDIR
@@ -88,7 +89,7 @@ int main(int argc, char **argv)
int c, status;
pid_t pid;
struct statfs st;
-
+
while ((c = getopt(argc, argv, "mpqrb:n:t:d:c:vo:u:")) != EOF)
{
switch (c) {
@@ -210,15 +211,12 @@ int main(int argc, char **argv)
if (statfs("/mnt/relay", &st) == 0
&& (int) st.f_type == (int) RELAYFS_MAGIC)
- sprintf(stpd_filebase, "/mnt/relay/%d/cpu", getpid());
- else {
- char *ptr;
- sprintf(stpd_filebase, "/proc/systemtap/%s", modname);
- ptr = index(stpd_filebase,'.');
- if (ptr)
- *ptr = 0;
- strcat(stpd_filebase, "/cpu");
- }
+ sprintf(stpd_filebase, "/mnt/relay/systemtap/%d/cpu", getpid());
+ else if (statfs("/sys/kernel/debug", &st) == 0
+ && (int) st.f_type == (int) DEBUGFS_MAGIC)
+ sprintf(stpd_filebase, "/sys/kernel/debug/systemtap/%d/cpu", getpid());
+ else
+ sprintf(stpd_filebase, "/debug/systemtap/%d/cpu", getpid());
if (init_stp(stpd_filebase, !quiet)) {
//fprintf(stderr, "Couldn't initialize stpd. Exiting.\n");
Index: runtime/transport/procfs.c
===================================================================
RCS file: /cvs/systemtap/src/runtime/transport/procfs.c,v
retrieving revision 1.17
diff -u -p -r1.17 procfs.c
--- runtime/transport/procfs.c 5 Jun 2006 23:53:48 -0000 1.17
+++ runtime/transport/procfs.c 14 Sep 2006 13:14:20 -0000
@@ -267,38 +267,6 @@ err:
return _stp_current_buffers;
}
-#if defined (STP_RELAYFS) && defined(CONFIG_RELAY)
-struct dentry *module_dir_dentry;
-
-static inline struct dentry *_stp_get_proc_root(void)
-{
- struct file_system_type *procfs_type;
- struct super_block *procfs_sb;
-
- procfs_type = get_fs_type("proc");
- if (!procfs_type || list_empty(&procfs_type->fs_supers))
- return NULL;
- procfs_sb = list_entry(procfs_type->fs_supers.next,
- struct super_block, s_instances);
- return procfs_sb->s_root;
-}
-
-static inline struct dentry *_stp_force_dir_creation(const char *dirname, struct dentry *parent)
-{
- struct dentry *dir_dentry;
-
- mutex_lock(&parent->d_inode->i_mutex);
- dir_dentry = lookup_one_len(dirname, parent, strlen(dirname));
- mutex_unlock(&parent->d_inode->i_mutex);
- if (IS_ERR(dir_dentry)) {
- dir_dentry = NULL;
- remove_proc_entry(dirname, NULL);
- }
-
- return dir_dentry;
-}
-#endif /* STP_RELAYFS && CONFIG_RELAY */
-
static int _stp_register_procfs (void)
{
int i;
@@ -307,10 +275,6 @@ static int _stp_register_procfs (void)
int j;
char buf[8];
#endif
-#if defined (CONFIG_RELAY)
- struct dentry *proc_root_dentry;
- struct dentry *systemtap_dir_dentry;
-#endif /* CONFIG_RELAY */
struct proc_dir_entry *de;
struct list_head *p, *tmp;
@@ -342,23 +306,11 @@ static int _stp_register_procfs (void)
goto err0;
}
-#if defined (STP_RELAYFS) && defined (CONFIG_RELAY)
- proc_root_dentry = _stp_get_proc_root();
- systemtap_dir_dentry = _stp_force_dir_creation(dirname, proc_root_dentry);
- if (!systemtap_dir_dentry)
- goto err0;
-#endif /* STP_RELAYFS && CONFIG_RELAY */
/* now create /proc/systemtap/module_name */
_stp_proc_mod = proc_mkdir (THIS_MODULE->name, _stp_proc_root);
if (_stp_proc_mod == NULL)
goto err0;
-#if defined (STP_RELAYFS) && defined (CONFIG_RELAY)
- module_dir_dentry = _stp_force_dir_creation(THIS_MODULE->name, systemtap_dir_dentry);
- if (!module_dir_dentry)
- goto err0;
-#endif /* STP_RELAYFS && CONFIG_RELAY */
-
#ifdef STP_RELAYFS
/* now for each cpu "n", create /proc/systemtap/module_name/n */
for_each_cpu(i) {
Index: runtime/transport/relayfs.c
===================================================================
RCS file: /cvs/systemtap/src/runtime/transport/relayfs.c,v
retrieving revision 1.4
diff -u -p -r1.4 relayfs.c
--- runtime/transport/relayfs.c 16 Mar 2006 15:14:39 -0000 1.4
+++ runtime/transport/relayfs.c 14 Sep 2006 13:14:21 -0000
@@ -78,35 +78,15 @@ static struct dentry *_stp_create_buf_fi
struct rchan_buf *buf,
int *is_global)
{
- struct proc_dir_entry *pde;
- struct dentry *dentry;
- struct proc_dir_entry *parent_pde = NULL;
-
- if (parent)
- parent_pde = PDE(parent->d_inode);
- pde = create_proc_entry(filename, S_IFREG|S_IRUSR, parent_pde);
- if (unlikely(!pde))
- return NULL;
- pde->proc_fops = &relay_file_operations;
-
- mutex_lock(&parent->d_inode->i_mutex);
- dentry = lookup_one_len(filename, parent, strlen(filename));
- mutex_unlock(&parent->d_inode->i_mutex);
- if (IS_ERR(dentry))
- remove_proc_entry(filename, parent_pde);
-
- dentry->d_inode->u.generic_ip = buf;
-
- return dentry;
+ return debugfs_create_file(filename, mode, parent, buf,
+ &relay_file_operations);
}
static int _stp_remove_buf_file(struct dentry *dentry)
{
- struct proc_dir_entry *pde = PDE(dentry->d_inode);
-
- remove_proc_entry(pde->name, pde->parent);
+ debugfs_remove(dentry);
- return 0;
+ return 0;
}
#endif /* CONFIG_RELAY */
@@ -128,34 +108,85 @@ static struct rchan_callbacks stp_rchan_
};
#endif /* CONFIG_RELAY */
-/**
- * _stp_relayfs_close - destroys relayfs channel
- * @chan: the relayfs channel
- * @dir: the directory containing the relayfs files
- */
+static struct dentry *create_relay_dir(const char *dirname, struct dentry *parent)
+{
+ struct dentry *dir;
+
#if defined (CONFIG_RELAY)
-void _stp_relayfs_close(struct rchan *chan, struct dentry *dir)
+ dir = debugfs_create_dir(dirname, parent);
+ if (IS_ERR(dir)) {
+ printk("STP: Couldn't create directory %s - debugfs not configured in.\n", dirname);
+ dir = NULL;
+ }
+#else
+ dir = relayfs_create_dir(dirname, parent);
+#endif
+
+ return dir;
+}
+
+static void remove_relay_dir(struct dentry *dir)
{
- if (!chan)
+ if (dir == NULL)
return;
-
- relay_close(chan);
- if (dir) {
- struct proc_dir_entry *pde = PDE(dir->d_inode);
- remove_proc_entry(pde->name, pde->parent);
- }
+
+#if defined (CONFIG_RELAY)
+ debugfs_remove(dir);
+#else
+ relayfs_remove_dir(dir);
+#endif
}
+
+static struct dentry *get_relay_root(void)
+{
+ struct file_system_type *fs;
+ struct super_block *sb;
+ struct dentry *root;
+ char *dirname = "systemtap";
+
+ root = create_relay_dir(dirname, NULL);
+ if (root)
+ return root;
+
+#if defined (CONFIG_RELAY)
+ fs = get_fs_type("debugfs");
#else
+ fs = get_fs_type("relayfs");
+#endif
+ if (!fs)
+ return NULL;
+
+ sb = list_entry(fs->fs_supers.next, struct super_block, s_instances);
+ mutex_lock(&sb->s_root->d_inode->i_mutex);
+ root = lookup_one_len(dirname, sb->s_root, strlen(dirname));
+ mutex_unlock(&sb->s_root->d_inode->i_mutex);
+ if (!IS_ERR(root))
+ dput(root);
+
+ return root;
+}
+
+static void put_relay_root(struct dentry *root)
+{
+ if (root)
+ remove_relay_dir(root);
+}
+
+static struct dentry *_relay_root;
+
+/**
+ * _stp_relayfs_close - destroys relayfs channel
+ * @chan: the relayfs channel
+ * @dir: the directory containing the relayfs files
+ */
void _stp_relayfs_close(struct rchan *chan, struct dentry *dir)
{
if (!chan)
return;
-
relay_close(chan);
- if (dir)
- relayfs_remove_dir(dir);
+ remove_relay_dir(dir);
+ put_relay_root(_relay_root);
}
-#endif /* CONFIG_RELAY */
/**
* _stp_relayfs_open - create relayfs channel
@@ -163,56 +194,35 @@ void _stp_relayfs_close(struct rchan *ch
* @subbuf_size: size of relayfs sub-buffers
* @pid: daemon pid
* @outdir: receives directory dentry
- * @parentdir: parent directory dentry
*
* Returns relay channel, NULL on failure
*
* Creates relayfs files as /systemtap/pid/cpuX in relayfs root
*/
-#if defined (CONFIG_RELAY)
-extern struct dentry *module_dentry;
struct rchan *_stp_relayfs_open(unsigned n_subbufs,
unsigned subbuf_size,
int pid,
- struct dentry **outdir,
- struct dentry *parent_dir)
+ struct dentry **outdir)
{
char dirname[16];
struct rchan *chan;
- struct dentry* dir = NULL;
+ struct dentry* root, *dir;
sprintf(dirname, "%d", pid);
- /* TODO: need to create systemtap dir */
- chan = relay_open("cpu", parent_dir, subbuf_size,
- n_subbufs, &stp_rchan_callbacks);
- if (!chan) {
- printk("STP: couldn't create relayfs channel.\n");
- if (dir)
- remove_proc_entry(dirname, NULL);
+ root = get_relay_root();
+ if (!root) {
+ printk("STP: couldn't get relay root dir.\n");
+ return NULL;
}
- *outdir = dir;
- return chan;
-}
-#else
-struct rchan *_stp_relayfs_open(unsigned n_subbufs,
- unsigned subbuf_size,
- int pid,
- struct dentry **outdir)
-{
- char dirname[16];
- struct rchan *chan;
- struct dentry* dir = NULL;
- sprintf(dirname, "%d", pid);
-
- /* TODO: need to create systemtap dir */
- dir = relayfs_create_dir(dirname, NULL);
+ dir = create_relay_dir(dirname, root);
if (!dir) {
- printk("STP: couldn't create relayfs dir %s.\n", dirname);
+ printk("STP: couldn't create relay dir %s.\n", dirname);
+ put_relay_root(root);
return NULL;
}
-
+
#if (RELAYFS_CHANNEL_VERSION >= 4)
chan = relay_open("cpu", dir, subbuf_size,
n_subbufs, &stp_rchan_callbacks);
@@ -222,15 +232,15 @@ struct rchan *_stp_relayfs_open(unsigned
#endif /* RELAYFS_CHANNEL_VERSION >= 4 */
if (!chan) {
- printk("STP: couldn't create relayfs channel.\n");
- if (dir)
- relayfs_remove_dir(dir);
+ printk("STP: couldn't create relay channel.\n");
+ remove_relay_dir(dir);
+ put_relay_root(root);
}
+ _relay_root = root;
*outdir = dir;
return chan;
}
-#endif /* CONFIG_RELAY */
#endif /* _TRANSPORT_RELAYFS_C_ */
Index: runtime/transport/relayfs.h
===================================================================
RCS file: /cvs/systemtap/src/runtime/transport/relayfs.h,v
retrieving revision 1.4
diff -u -p -r1.4 relayfs.h
--- runtime/transport/relayfs.h 16 Mar 2006 15:14:39 -0000 1.4
+++ runtime/transport/relayfs.h 14 Sep 2006 13:14:21 -0000
@@ -9,23 +9,17 @@
# include <linux/relayfs_fs.h>
#elif defined (CONFIG_RELAY)
# include <linux/relay.h>
-# include <linux/namei.h>
+# include <linux/debugfs.h>
#else
# undef STP_RELAYFS
#endif
-#if defined (CONFIG_RELAY)
-struct rchan *_stp_relayfs_open(unsigned n_subbufs,
- unsigned subbuf_size,
- int pid,
- struct dentry **outdir,
- struct dentry *parent_dir);
-#else
+# include <linux/namei.h>
+
struct rchan *_stp_relayfs_open(unsigned n_subbufs,
unsigned subbuf_size,
int pid,
struct dentry **outdir);
-#endif
void _stp_relayfs_close(struct rchan *chan, struct dentry *dir);
Index: runtime/transport/transport.c
===================================================================
RCS file: /cvs/systemtap/src/runtime/transport/transport.c,v
retrieving revision 1.25
diff -u -p -r1.25 transport.c
--- runtime/transport/transport.c 22 Jun 2006 00:48:33 -0000 1.25
+++ runtime/transport/transport.c 14 Sep 2006 13:14:21 -0000
@@ -203,10 +203,6 @@ void _stp_transport_close()
kbug("---- CLOSED ----\n");
}
-#if defined (STP_RELAYFS) && defined (CONFIG_RELAY)
-extern struct dentry *module_dir_dentry;
-#endif /* STP_RELAYFS && CONFIG_RELAY */
-
/**
* _stp_transport_open - open proc and relayfs channels
* with proper parameters
@@ -240,11 +236,8 @@ int _stp_transport_open(struct transport
info->n_subbufs = n_subbufs;
info->subbuf_size = subbuf_size;
-#if defined (CONFIG_RELAY)
- _stp_chan = _stp_relayfs_open(n_subbufs, subbuf_size, _stp_pid, &_stp_dir, module_dir_dentry);
-#else
_stp_chan = _stp_relayfs_open(n_subbufs, subbuf_size, _stp_pid, &_stp_dir);
-#endif /* CONFIG_RELAY */
+
if (!_stp_chan) {
_stp_unregister_procfs();
return -ENOMEM;