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Commit 4862fd60 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

jbd2: remove jbd2_dev_to_name() from jbd2 tracepoints 



Using function calls in TP_printk causes perf heartburn, so print the
MAJOR/MINOR device numbers instead.

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 575a1d4b

fs/jbd2/journal.c

+0 −67
Original line number Diff line number Diff line
@@ -2390,73 +2390,6 @@ 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;

	static struct devname_cache *new_dev;



	rcu_read_lock();

	if (devcache[i] && devcache[i]->device == device) {

		ret = devcache[i]->devname;

		rcu_read_unlock();

		return ret;

	}

	rcu_read_unlock();



	new_dev = kmalloc(sizeof(struct devname_cache), GFP_KERNEL);

	if (!new_dev)

		return "NODEV-ALLOCFAILURE"; /* Something non-NULL */

	bd = bdget(device);

	spin_lock(&devname_cache_lock);

	if (devcache[i]) {

		if (devcache[i]->device == device) {

			kfree(new_dev);

			bdput(bd);

			ret = devcache[i]->devname;

			spin_unlock(&devname_cache_lock);

			return ret;

		}

		call_rcu(&devcache[i]->rcu, free_devcache);

	}

	devcache[i] = new_dev;

	devcache[i]->device = 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

+0 −6
Original line number Diff line number Diff line
@@ -1329,12 +1329,6 @@ 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

+19 −17
Original line number Diff line number Diff line
@@ -26,8 +26,8 @@ TRACE_EVENT(jbd2_checkpoint, 
		__entry->result		= result;

	),



	TP_printk("dev %s result %d",

		  jbd2_dev_to_name(__entry->dev), __entry->result)

	TP_printk("dev %d,%d result %d",

		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->result)

);



DECLARE_EVENT_CLASS(jbd2_commit,
@@ -48,9 +48,9 @@ DECLARE_EVENT_CLASS(jbd2_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)

	TP_printk("dev %d,%d transaction %d sync %d",

		  MAJOR(__entry->dev), MINOR(__entry->dev),

		  __entry->transaction, __entry->sync_commit)

);



DEFINE_EVENT(jbd2_commit, jbd2_start_commit,
@@ -100,9 +100,9 @@ TRACE_EVENT(jbd2_end_commit, 
		__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)

	TP_printk("dev %d,%d transaction %d sync %d head %d",

		  MAJOR(__entry->dev), MINOR(__entry->dev),

		  __entry->transaction, __entry->sync_commit, __entry->head)

);



TRACE_EVENT(jbd2_submit_inode_data,
@@ -120,8 +120,9 @@ TRACE_EVENT(jbd2_submit_inode_data, 
		__entry->ino	= inode->i_ino;

	),



	TP_printk("dev %s ino %lu",

		  jbd2_dev_to_name(__entry->dev), (unsigned long) __entry->ino)

	TP_printk("dev %d,%d ino %lu",

		  MAJOR(__entry->dev), MINOR(__entry->dev),

		  (unsigned long) __entry->ino)

);



TRACE_EVENT(jbd2_run_stats,
@@ -156,9 +157,9 @@ TRACE_EVENT(jbd2_run_stats, 
		__entry->blocks_logged	= stats->rs_blocks_logged;

	),



	TP_printk("dev %s tid %lu wait %u running %u locked %u flushing %u "

	TP_printk("dev %d,%d tid %lu wait %u running %u locked %u flushing %u "

		  "logging %u handle_count %u blocks %u blocks_logged %u",

		  jbd2_dev_to_name(__entry->dev), __entry->tid,

		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->tid,

		  jiffies_to_msecs(__entry->wait),

		  jiffies_to_msecs(__entry->running),

		  jiffies_to_msecs(__entry->locked),
@@ -192,9 +193,9 @@ TRACE_EVENT(jbd2_checkpoint_stats, 
		__entry->dropped	= stats->cs_dropped;

	),



	TP_printk("dev %s tid %lu chp_time %u forced_to_close %u "

	TP_printk("dev %d,%d tid %lu chp_time %u forced_to_close %u "

		  "written %u dropped %u",

		  jbd2_dev_to_name(__entry->dev), __entry->tid,

		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->tid,

		  jiffies_to_msecs(__entry->chp_time),

		  __entry->forced_to_close, __entry->written, __entry->dropped)

);
@@ -222,9 +223,10 @@ TRACE_EVENT(jbd2_cleanup_journal_tail, 
		__entry->freed		= freed;

	),



	TP_printk("dev %s from %u to %u offset %lu freed %lu",

		  jbd2_dev_to_name(__entry->dev), __entry->tail_sequence,

		  __entry->first_tid, __entry->block_nr, __entry->freed)

	TP_printk("dev %d,%d from %u to %u offset %lu freed %lu",

		  MAJOR(__entry->dev), MINOR(__entry->dev),

		  __entry->tail_sequence, __entry->first_tid,

		  __entry->block_nr, __entry->freed)

);



#endif /* _TRACE_JBD2_H */