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Date: Sun, 10 Jul 2011 23:28:25 -0400
From: Theodore Ts'o <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: Theodore Ts'o <tytso@....edu>
Subject: [PATCH] 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@....edu>
---
fs/jbd2/journal.c | 67 -------------------------------------------
include/linux/jbd2.h | 6 ----
include/trace/events/jbd2.h | 36 ++++++++++++-----------
3 files changed, 19 insertions(+), 90 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 0dfa5b5..f24df13 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -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);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index d087c2e..38f307b 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -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 */
diff --git a/include/trace/events/jbd2.h b/include/trace/events/jbd2.h
index bf16545..7596441 100644
--- a/include/trace/events/jbd2.h
+++ b/include/trace/events/jbd2.h
@@ -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 */
--
1.7.4.1.22.gec8e1.dirty
--
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