jbd2: convert instrumentation from markers to tracepoints

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/jbd2/checkpoint.c

@@ -20,9 +20,9 @@
 #include <linux/time.h>
 #include <linux/fs.h>
 #include <linux/jbd2.h>
-#include <linux/marker.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
+#include <trace/events/jbd2.h>
 
 /*
  * Unlink a buffer from a transaction checkpoint list.
@@ -358,8 +358,7 @@ int jbd2_log_do_checkpoint(journal_t *journal)
 	 * journal straight away.
 	 */
 	result = jbd2_cleanup_journal_tail(journal);
-	trace_mark(jbd2_checkpoint, "dev %s need_checkpoint %d",
-		   journal->j_devname, result);
+	trace_jbd2_checkpoint(journal, result);
 	jbd_debug(1, "cleanup_journal_tail returned %d\n", result);
 	if (result <= 0)
 		return result;

fs/jbd2/commit.c

@@ -16,7 +16,6 @@
 #include <linux/time.h>
 #include <linux/fs.h>
 #include <linux/jbd2.h>
-#include <linux/marker.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
@@ -26,6 +25,7 @@
 #include <linux/writeback.h>
 #include <linux/backing-dev.h>
 #include <linux/bio.h>
+#include <trace/events/jbd2.h>
 
 /*
  * Default IO end handler for temporary BJ_IO buffer_heads.
@@ -253,6 +253,7 @@ static int journal_submit_data_buffers(journal_t *journal,
 		 * block allocation  with delalloc. We need to write
 		 * only allocated blocks here.
 		 */
+		trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
 		err = journal_submit_inode_data_buffers(mapping);
 		if (!ret)
 			ret = err;
@@ -394,8 +395,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	commit_transaction = journal->j_running_transaction;
 	J_ASSERT(commit_transaction->t_state == T_RUNNING);
 
-	trace_mark(jbd2_start_commit, "dev %s transaction %d",
-		   journal->j_devname, commit_transaction->t_tid);
+	trace_jbd2_start_commit(journal, commit_transaction);
 	jbd_debug(1, "JBD: starting commit of transaction %d\n",
 			commit_transaction->t_tid);
 
@@ -409,6 +409,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	 */
 	if (commit_transaction->t_synchronous_commit)
 		write_op = WRITE_SYNC_PLUG;
+	trace_jbd2_commit_locking(journal, commit_transaction);
 	stats.u.run.rs_wait = commit_transaction->t_max_wait;
 	stats.u.run.rs_locked = jiffies;
 	stats.u.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
@@ -484,6 +485,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	 */
 	jbd2_journal_switch_revoke_table(journal);
 
+	trace_jbd2_commit_flushing(journal, commit_transaction);
 	stats.u.run.rs_flushing = jiffies;
 	stats.u.run.rs_locked = jbd2_time_diff(stats.u.run.rs_locked,
 					       stats.u.run.rs_flushing);
@@ -520,6 +522,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	commit_transaction->t_state = T_COMMIT;
 	spin_unlock(&journal->j_state_lock);
 
+	trace_jbd2_commit_logging(journal, commit_transaction);
 	stats.u.run.rs_logging = jiffies;
 	stats.u.run.rs_flushing = jbd2_time_diff(stats.u.run.rs_flushing,
 						 stats.u.run.rs_logging);
@@ -1054,9 +1057,7 @@ restart_loop:
 	if (journal->j_commit_callback)
 		journal->j_commit_callback(journal, commit_transaction);
 
-	trace_mark(jbd2_end_commit, "dev %s transaction %d head %d",
-		   journal->j_devname, commit_transaction->t_tid,
-		   journal->j_tail_sequence);
+	trace_jbd2_end_commit(journal, commit_transaction);
 	jbd_debug(1, "JBD: commit %d complete, head %d\n",
 		  journal->j_commit_sequence, journal->j_tail_sequence);
 	if (to_free)

fs/jbd2/journal.c

@@ -38,6 +38,10 @@
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
 #include <linux/math64.h>
+#include <linux/hash.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/jbd2.h>
 
 #include <asm/uaccess.h>
 #include <asm/page.h>
@@ -2377,6 +2381,71 @@ static void __exit journal_exit(void)
 	jbd2_journal_destroy_caches();
 }
 
+/* 
+ * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 
+ * tracing infrastructure to map a dev_t to a device name.
+ *
+ * The caller should use rcu_read_lock() in order to make sure the
+ * device name stays valid until its done with it.  We use
+ * rcu_read_lock() as well to make sure we're safe in case the caller
+ * gets sloppy, and because rcu_read_lock() is cheap and can be safely
+ * nested.
+ */
+struct devname_cache {
+	struct rcu_head	rcu;
+	dev_t		device;
+	char		devname[BDEVNAME_SIZE];
+};
+#define CACHE_SIZE_BITS 6
+static struct devname_cache *devcache[1 << CACHE_SIZE_BITS];
+static DEFINE_SPINLOCK(devname_cache_lock);
+
+static void free_devcache(struct rcu_head *rcu)
+{
+	kfree(rcu);
+}
+
+const char *jbd2_dev_to_name(dev_t device)
+{
+	int	i = hash_32(device, CACHE_SIZE_BITS);
+	char	*ret;
+	struct block_device *bd;
+
+	rcu_read_lock();
+	if (devcache[i] && devcache[i]->device == device) {
+		ret = devcache[i]->devname;
+		rcu_read_unlock();
+		return ret;
+	}
+	rcu_read_unlock();
+
+	spin_lock(&devname_cache_lock);
+	if (devcache[i]) {
+		if (devcache[i]->device == device) {
+			ret = devcache[i]->devname;
+			spin_unlock(&devname_cache_lock);
+			return ret;
+		}
+		call_rcu(&devcache[i]->rcu, free_devcache);
+	}
+	devcache[i] = kmalloc(sizeof(struct devname_cache), GFP_KERNEL);
+	if (!devcache[i]) {
+		spin_unlock(&devname_cache_lock);
+		return "NODEV-ALLOCFAILURE"; /* Something non-NULL */
+	}
+	devcache[i]->device = device;
+	bd = bdget(device);
+	if (bd) {
+		bdevname(bd, devcache[i]->devname);
+		bdput(bd);
+	} else
+		__bdevname(device, devcache[i]->devname);
+	ret = devcache[i]->devname;
+	spin_unlock(&devname_cache_lock);
+	return ret;
+}
+EXPORT_SYMBOL(jbd2_dev_to_name);
+
 MODULE_LICENSE("GPL");
 module_init(journal_init);
 module_exit(journal_exit);

include/linux/jbd2.h

@@ -1315,6 +1315,12 @@ extern int jbd_blocks_per_page(struct inode *inode);
 #define BUFFER_TRACE2(bh, bh2, info)	do {} while (0)
 #define JBUFFER_TRACE(jh, info)	do {} while (0)
 
+/* 
+ * jbd2_dev_to_name is a utility function used by the jbd2 and ext4 
+ * tracing infrastructure to map a dev_t to a device name.
+ */
+extern const char *jbd2_dev_to_name(dev_t device);
+
 #endif	/* __KERNEL__ */
 
 #endif	/* _LINUX_JBD2_H */

include/trace/events/jbd2.h

@@ -0,0 +1,168 @@
+#if !defined(_TRACE_JBD2_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_JBD2_H
+
+#include <linux/jbd2.h>
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM jbd2
+
+TRACE_EVENT(jbd2_checkpoint,
+
+	TP_PROTO(journal_t *journal, int result),
+
+	TP_ARGS(journal, result),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(	int,	result			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= journal->j_fs_dev->bd_dev;
+		__entry->result		= result;
+	),
+
+	TP_printk("dev %s result %d",
+		  jbd2_dev_to_name(__entry->dev), __entry->result)
+);
+
+TRACE_EVENT(jbd2_start_commit,
+
+	TP_PROTO(journal_t *journal, transaction_t *commit_transaction),
+
+	TP_ARGS(journal, commit_transaction),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(	char,	sync_commit		  )
+		__field(	int,	transaction		  )
+	),
+
+	TP_fast_assign(
+		__entry->dev		= journal->j_fs_dev->bd_dev;
+		__entry->sync_commit = commit_transaction->t_synchronous_commit;
+		__entry->transaction	= commit_transaction->t_tid;
+	),
+
+	TP_printk("dev %s transaction %d sync %d",
+		  jbd2_dev_to_name(__entry->dev), __entry->transaction,
+		  __entry->sync_commit)
+);
+
+TRACE_EVENT(jbd2_commit_locking,
+
+	TP_PROTO(journal_t *journal, transaction_t *commit_transaction),
+
+	TP_ARGS(journal, commit_transaction),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(	char,	sync_commit		  )
+		__field(	int,	transaction		  )
+	),
+
+	TP_fast_assign(
+		__entry->dev		= journal->j_fs_dev->bd_dev;
+		__entry->sync_commit = commit_transaction->t_synchronous_commit;
+		__entry->transaction	= commit_transaction->t_tid;
+	),
+
+	TP_printk("dev %s transaction %d sync %d",
+		  jbd2_dev_to_name(__entry->dev), __entry->transaction,
+		  __entry->sync_commit)
+);
+
+TRACE_EVENT(jbd2_commit_flushing,
+
+	TP_PROTO(journal_t *journal, transaction_t *commit_transaction),
+
+	TP_ARGS(journal, commit_transaction),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(	char,	sync_commit		  )
+		__field(	int,	transaction		  )
+	),
+
+	TP_fast_assign(
+		__entry->dev		= journal->j_fs_dev->bd_dev;
+		__entry->sync_commit = commit_transaction->t_synchronous_commit;
+		__entry->transaction	= commit_transaction->t_tid;
+	),
+
+	TP_printk("dev %s transaction %d sync %d",
+		  jbd2_dev_to_name(__entry->dev), __entry->transaction,
+		  __entry->sync_commit)
+);
+
+TRACE_EVENT(jbd2_commit_logging,
+
+	TP_PROTO(journal_t *journal, transaction_t *commit_transaction),
+
+	TP_ARGS(journal, commit_transaction),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(	char,	sync_commit		  )
+		__field(	int,	transaction		  )
+	),
+
+	TP_fast_assign(
+		__entry->dev		= journal->j_fs_dev->bd_dev;
+		__entry->sync_commit = commit_transaction->t_synchronous_commit;
+		__entry->transaction	= commit_transaction->t_tid;
+	),
+
+	TP_printk("dev %s transaction %d sync %d",
+		  jbd2_dev_to_name(__entry->dev), __entry->transaction,
+		  __entry->sync_commit)
+);
+
+TRACE_EVENT(jbd2_end_commit,
+	TP_PROTO(journal_t *journal, transaction_t *commit_transaction),
+
+	TP_ARGS(journal, commit_transaction),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(	char,	sync_commit		  )
+		__field(	int,	transaction		  )
+		__field(	int,	head		  	  )
+	),
+
+	TP_fast_assign(
+		__entry->dev		= journal->j_fs_dev->bd_dev;
+		__entry->sync_commit = commit_transaction->t_synchronous_commit;
+		__entry->transaction	= commit_transaction->t_tid;
+		__entry->head		= journal->j_tail_sequence;
+	),
+
+	TP_printk("dev %s transaction %d sync %d head %d",
+		  jbd2_dev_to_name(__entry->dev), __entry->transaction,
+		  __entry->sync_commit, __entry->head)
+);
+
+TRACE_EVENT(jbd2_submit_inode_data,
+	TP_PROTO(struct inode *inode),
+
+	TP_ARGS(inode),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,	dev			)
+		__field(	ino_t,	ino			)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= inode->i_sb->s_dev;
+		__entry->ino	= inode->i_ino;
+	),
+
+	TP_printk("dev %s ino %lu",
+		  jbd2_dev_to_name(__entry->dev), __entry->ino)
+);
+
+#endif /* _TRACE_JBD2_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>