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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: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2011-07-10 22:05:08 -04:00
parent 575a1d4bdf
commit 4862fd6047
3 changed files with 19 additions and 90 deletions
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67
fs/jbd2/journal.c
View File

@ -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);

6
include/linux/jbd2.h
View File

@ -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 */

36
include/trace/events/jbd2.h
View File

@ -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 */