[PATCH 32/49] jbd2: jbd2 stats through procfs

From: Theodore Ts'o
Date: Mon Jan 21 2008 - 22:21:48 EST

From: Johann Lombardi <johann.lombardi@xxxxxxxx>

The patch below updates the jbd stats patch to 2.6.20/jbd2.
The initial patch was posted by Alex Tomas in December 2005
(http://marc.info/?l=linux-ext4&m=113538565128617&w=2).
It provides statistics via procfs such as transaction lifetime and size.

Sometimes, investigating performance problems, i find useful to have
stats from jbd about transaction's lifetime, size, etc. here is a
patch for review and inclusion probably.

for example, stats after creation of 3M files in htree directory:

[root@bob ~]# cat /proc/fs/jbd/sda/history
R/C tid wait run lock flush log hndls block inlog ctime write drop close
R 261 8260 2720 0 0 750 9892 8170 8187
C 259 750 0 4885 1
R 262 20 2200 10 0 770 9836 8170 8187
R 263 30 2200 10 0 3070 9812 8170 8187
R 264 0 5000 10 0 1340 0 0 0
C 261 8240 3212 4957 0
R 265 8260 1470 0 0 4640 9854 8170 8187
R 266 0 5000 10 0 1460 0 0 0
C 262 8210 2989 4868 0
R 267 8230 1490 10 0 4440 9875 8171 8188
R 268 0 5000 10 0 1260 0 0 0
C 263 7710 2937 4908 0
R 269 7730 1470 10 0 3330 9841 8170 8187
R 270 0 5000 10 0 830 0 0 0
C 265 8140 3234 4898 0
C 267 720 0 4849 1
R 271 8630 2740 20 0 740 9819 8170 8187
C 269 800 0 4214 1
R 272 40 2170 10 0 830 9716 8170 8187
R 273 40 2280 0 0 3530 9799 8170 8187
R 274 0 5000 10 0 990 0 0 0


where,

R - line for transaction's life from T_RUNNING to T_FINISHED
C - line for transaction's checkpointing
tid - transaction's id
wait - for how long we were waiting for new transaction to start
(the longest period journal_start() took in this transaction)
run - real transaction's lifetime (from T_RUNNING to T_LOCKED
lock - how long we were waiting for all handles to close
(time the transaction was in T_LOCKED)
flush - how long it took to flush all data (data=ordered)
log - how long it took to write the transaction to the log
hndls - how many handles got to the transaction
block - how many blocks got to the transaction
inlog - how many blocks are written to the log (block + descriptors)
ctime - how long it took to checkpoint the transaction
write - how many blocks have been written during checkpointing
drop - how many blocks have been dropped during checkpointing
close - how many running transactions have been closed to checkpoint this one

all times are in msec.


[root@bob ~]# cat /proc/fs/jbd/sda/info
280 transaction, each upto 8192 blocks
average:
1633ms waiting for transaction
3616ms running transaction
5ms transaction was being locked
1ms flushing data (in ordered mode)
1799ms logging transaction
11781 handles per transaction
5629 blocks per transaction
5641 logged blocks per transaction

Signed-off-by: Johann Lombardi <johann.lombardi@xxxxxxxx>
Signed-off-by: Mariusz Kozlowski <m.kozlowski@xxxxxxxxxx>
Signed-off-by: Mingming Cao <cmm@xxxxxxxxxx>
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
fs/jbd2/checkpoint.c | 10 +-
fs/jbd2/commit.c | 49 +++++++
fs/jbd2/journal.c | 338 +++++++++++++++++++++++++++++++++++++++++++++++++
fs/jbd2/transaction.c | 9 ++
include/linux/jbd2.h | 77 +++++++++++
5 files changed, 481 insertions(+), 2 deletions(-)

diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 7e958c8..1b7f282 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -232,7 +232,8 @@ __flush_batch(journal_t *journal, struct buffer_head **bhs, int *batch_count)
* Called under jbd_lock_bh_state(jh2bh(jh)), and drops it
*/
static int __process_buffer(journal_t *journal, struct journal_head *jh,
- struct buffer_head **bhs, int *batch_count)
+ struct buffer_head **bhs, int *batch_count,
+ transaction_t *transaction)
{
struct buffer_head *bh = jh2bh(jh);
int ret = 0;
@@ -250,6 +251,7 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
transaction_t *t = jh->b_transaction;
tid_t tid = t->t_tid;

+ transaction->t_chp_stats.cs_forced_to_close++;
spin_unlock(&journal->j_list_lock);
jbd_unlock_bh_state(bh);
jbd2_log_start_commit(journal, tid);
@@ -279,6 +281,7 @@ static int __process_buffer(journal_t *journal, struct journal_head *jh,
bhs[*batch_count] = bh;
__buffer_relink_io(jh);
jbd_unlock_bh_state(bh);
+ transaction->t_chp_stats.cs_written++;
(*batch_count)++;
if (*batch_count == NR_BATCH) {
spin_unlock(&journal->j_list_lock);
@@ -322,6 +325,8 @@ int jbd2_log_do_checkpoint(journal_t *journal)
if (!journal->j_checkpoint_transactions)
goto out;
transaction = journal->j_checkpoint_transactions;
+ if (transaction->t_chp_stats.cs_chp_time == 0)
+ transaction->t_chp_stats.cs_chp_time = jiffies;
this_tid = transaction->t_tid;
restart:
/*
@@ -346,7 +351,8 @@ restart:
retry = 1;
break;
}
- retry = __process_buffer(journal, jh, bhs,&batch_count);
+ retry = __process_buffer(journal, jh, bhs, &batch_count,
+ transaction);
if (!retry && lock_need_resched(&journal->j_list_lock)){
spin_unlock(&journal->j_list_lock);
retry = 1;
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 39b5cee..8749a86 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -20,6 +20,7 @@
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
+#include <linux/jiffies.h>

/*
* Default IO end handler for temporary BJ_IO buffer_heads.
@@ -290,6 +291,7 @@ static inline void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
*/
void jbd2_journal_commit_transaction(journal_t *journal)
{
+ struct transaction_stats_s stats;
transaction_t *commit_transaction;
struct journal_head *jh, *new_jh, *descriptor;
struct buffer_head **wbuf = journal->j_wbuf;
@@ -337,6 +339,11 @@ void jbd2_journal_commit_transaction(journal_t *journal)
spin_lock(&journal->j_state_lock);
commit_transaction->t_state = T_LOCKED;

+ 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,
+ stats.u.run.rs_locked);
+
spin_lock(&commit_transaction->t_handle_lock);
while (commit_transaction->t_updates) {
DEFINE_WAIT(wait);
@@ -407,6 +414,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
*/
jbd2_journal_switch_revoke_table(journal);

+ stats.u.run.rs_flushing = jiffies;
+ stats.u.run.rs_locked = jbd2_time_diff(stats.u.run.rs_locked,
+ stats.u.run.rs_flushing);
+
commit_transaction->t_state = T_FLUSH;
journal->j_committing_transaction = commit_transaction;
journal->j_running_transaction = NULL;
@@ -498,6 +509,12 @@ void jbd2_journal_commit_transaction(journal_t *journal)
*/
commit_transaction->t_state = T_COMMIT;

+ stats.u.run.rs_logging = jiffies;
+ stats.u.run.rs_flushing = jbd2_time_diff(stats.u.run.rs_flushing,
+ stats.u.run.rs_logging);
+ stats.u.run.rs_blocks = commit_transaction->t_outstanding_credits;
+ stats.u.run.rs_blocks_logged = 0;
+
descriptor = NULL;
bufs = 0;
while (commit_transaction->t_buffers) {
@@ -646,6 +663,7 @@ start_journal_io:
submit_bh(WRITE, bh);
}
cond_resched();
+ stats.u.run.rs_blocks_logged += bufs;

/* Force a new descriptor to be generated next
time round the loop. */
@@ -816,6 +834,7 @@ restart_loop:
cp_transaction = jh->b_cp_transaction;
if (cp_transaction) {
JBUFFER_TRACE(jh, "remove from old cp transaction");
+ cp_transaction->t_chp_stats.cs_dropped++;
__jbd2_journal_remove_checkpoint(jh);
}

@@ -890,6 +909,36 @@ restart_loop:

J_ASSERT(commit_transaction->t_state == T_COMMIT);

+ commit_transaction->t_start = jiffies;
+ stats.u.run.rs_logging = jbd2_time_diff(stats.u.run.rs_logging,
+ commit_transaction->t_start);
+
+ /*
+ * File the transaction for history
+ */
+ stats.ts_type = JBD2_STATS_RUN;
+ stats.ts_tid = commit_transaction->t_tid;
+ stats.u.run.rs_handle_count = commit_transaction->t_handle_count;
+ spin_lock(&journal->j_history_lock);
+ memcpy(journal->j_history + journal->j_history_cur, &stats,
+ sizeof(stats));
+ if (++journal->j_history_cur == journal->j_history_max)
+ journal->j_history_cur = 0;
+
+ /*
+ * Calculate overall stats
+ */
+ journal->j_stats.ts_tid++;
+ journal->j_stats.u.run.rs_wait += stats.u.run.rs_wait;
+ journal->j_stats.u.run.rs_running += stats.u.run.rs_running;
+ journal->j_stats.u.run.rs_locked += stats.u.run.rs_locked;
+ journal->j_stats.u.run.rs_flushing += stats.u.run.rs_flushing;
+ journal->j_stats.u.run.rs_logging += stats.u.run.rs_logging;
+ journal->j_stats.u.run.rs_handle_count += stats.u.run.rs_handle_count;
+ journal->j_stats.u.run.rs_blocks += stats.u.run.rs_blocks;
+ journal->j_stats.u.run.rs_blocks_logged += stats.u.run.rs_blocks_logged;
+ spin_unlock(&journal->j_history_lock);
+
commit_transaction->t_state = T_FINISHED;
J_ASSERT(commit_transaction == journal->j_committing_transaction);
journal->j_commit_sequence = commit_transaction->t_tid;
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 6ddc553..3667c91 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -36,6 +36,7 @@
#include <linux/poison.h>
#include <linux/proc_fs.h>
#include <linux/debugfs.h>
+#include <linux/seq_file.h>

#include <asm/uaccess.h>
#include <asm/page.h>
@@ -640,6 +641,312 @@ struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
return jbd2_journal_add_journal_head(bh);
}

+struct jbd2_stats_proc_session {
+ journal_t *journal;
+ struct transaction_stats_s *stats;
+ int start;
+ int max;
+};
+
+static void *jbd2_history_skip_empty(struct jbd2_stats_proc_session *s,
+ struct transaction_stats_s *ts,
+ int first)
+{
+ if (ts == s->stats + s->max)
+ ts = s->stats;
+ if (!first && ts == s->stats + s->start)
+ return NULL;
+ while (ts->ts_type == 0) {
+ ts++;
+ if (ts == s->stats + s->max)
+ ts = s->stats;
+ if (ts == s->stats + s->start)
+ return NULL;
+ }
+ return ts;
+
+}
+
+static void *jbd2_seq_history_start(struct seq_file *seq, loff_t *pos)
+{
+ struct jbd2_stats_proc_session *s = seq->private;
+ struct transaction_stats_s *ts;
+ int l = *pos;
+
+ if (l == 0)
+ return SEQ_START_TOKEN;
+ ts = jbd2_history_skip_empty(s, s->stats + s->start, 1);
+ if (!ts)
+ return NULL;
+ l--;
+ while (l) {
+ ts = jbd2_history_skip_empty(s, ++ts, 0);
+ if (!ts)
+ break;
+ l--;
+ }
+ return ts;
+}
+
+static void *jbd2_seq_history_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ struct jbd2_stats_proc_session *s = seq->private;
+ struct transaction_stats_s *ts = v;
+
+ ++*pos;
+ if (v == SEQ_START_TOKEN)
+ return jbd2_history_skip_empty(s, s->stats + s->start, 1);
+ else
+ return jbd2_history_skip_empty(s, ++ts, 0);
+}
+
+static int jbd2_seq_history_show(struct seq_file *seq, void *v)
+{
+ struct transaction_stats_s *ts = v;
+ if (v == SEQ_START_TOKEN) {
+ seq_printf(seq, "%-4s %-5s %-5s %-5s %-5s %-5s %-5s %-6s %-5s "
+ "%-5s %-5s %-5s %-5s %-5s\n", "R/C", "tid",
+ "wait", "run", "lock", "flush", "log", "hndls",
+ "block", "inlog", "ctime", "write", "drop",
+ "close");
+ return 0;
+ }
+ if (ts->ts_type == JBD2_STATS_RUN)
+ seq_printf(seq, "%-4s %-5lu %-5u %-5u %-5u %-5u %-5u "
+ "%-6lu %-5lu %-5lu\n", "R", ts->ts_tid,
+ jiffies_to_msecs(ts->u.run.rs_wait),
+ jiffies_to_msecs(ts->u.run.rs_running),
+ jiffies_to_msecs(ts->u.run.rs_locked),
+ jiffies_to_msecs(ts->u.run.rs_flushing),
+ jiffies_to_msecs(ts->u.run.rs_logging),
+ ts->u.run.rs_handle_count,
+ ts->u.run.rs_blocks,
+ ts->u.run.rs_blocks_logged);
+ else if (ts->ts_type == JBD2_STATS_CHECKPOINT)
+ seq_printf(seq, "%-4s %-5lu %48s %-5u %-5lu %-5lu %-5lu\n",
+ "C", ts->ts_tid, " ",
+ jiffies_to_msecs(ts->u.chp.cs_chp_time),
+ ts->u.chp.cs_written, ts->u.chp.cs_dropped,
+ ts->u.chp.cs_forced_to_close);
+ else
+ J_ASSERT(0);
+ return 0;
+}
+
+static void jbd2_seq_history_stop(struct seq_file *seq, void *v)
+{
+}
+
+static struct seq_operations jbd2_seq_history_ops = {
+ .start = jbd2_seq_history_start,
+ .next = jbd2_seq_history_next,
+ .stop = jbd2_seq_history_stop,
+ .show = jbd2_seq_history_show,
+};
+
+static int jbd2_seq_history_open(struct inode *inode, struct file *file)
+{
+ journal_t *journal = PDE(inode)->data;
+ struct jbd2_stats_proc_session *s;
+ int rc, size;
+
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
+ if (s == NULL)
+ return -ENOMEM;
+ size = sizeof(struct transaction_stats_s) * journal->j_history_max;
+ s->stats = kmalloc(size, GFP_KERNEL);
+ if (s->stats == NULL) {
+ kfree(s);
+ return -ENOMEM;
+ }
+ spin_lock(&journal->j_history_lock);
+ memcpy(s->stats, journal->j_history, size);
+ s->max = journal->j_history_max;
+ s->start = journal->j_history_cur % s->max;
+ spin_unlock(&journal->j_history_lock);
+
+ rc = seq_open(file, &jbd2_seq_history_ops);
+ if (rc == 0) {
+ struct seq_file *m = file->private_data;
+ m->private = s;
+ } else {
+ kfree(s->stats);
+ kfree(s);
+ }
+ return rc;
+
+}
+
+static int jbd2_seq_history_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+ struct jbd2_stats_proc_session *s = seq->private;
+
+ kfree(s->stats);
+ kfree(s);
+ return seq_release(inode, file);
+}
+
+static struct file_operations jbd2_seq_history_fops = {
+ .owner = THIS_MODULE,
+ .open = jbd2_seq_history_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = jbd2_seq_history_release,
+};
+
+static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
+{
+ return *pos ? NULL : SEQ_START_TOKEN;
+}
+
+static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+ return NULL;
+}
+
+static int jbd2_seq_info_show(struct seq_file *seq, void *v)
+{
+ struct jbd2_stats_proc_session *s = seq->private;
+
+ if (v != SEQ_START_TOKEN)
+ return 0;
+ seq_printf(seq, "%lu transaction, each upto %u blocks\n",
+ s->stats->ts_tid,
+ s->journal->j_max_transaction_buffers);
+ if (s->stats->ts_tid == 0)
+ return 0;
+ seq_printf(seq, "average: \n %ums waiting for transaction\n",
+ jiffies_to_msecs(s->stats->u.run.rs_wait / s->stats->ts_tid));
+ seq_printf(seq, " %ums running transaction\n",
+ jiffies_to_msecs(s->stats->u.run.rs_running / s->stats->ts_tid));
+ seq_printf(seq, " %ums transaction was being locked\n",
+ jiffies_to_msecs(s->stats->u.run.rs_locked / s->stats->ts_tid));
+ seq_printf(seq, " %ums flushing data (in ordered mode)\n",
+ jiffies_to_msecs(s->stats->u.run.rs_flushing / s->stats->ts_tid));
+ seq_printf(seq, " %ums logging transaction\n",
+ jiffies_to_msecs(s->stats->u.run.rs_logging / s->stats->ts_tid));
+ seq_printf(seq, " %lu handles per transaction\n",
+ s->stats->u.run.rs_handle_count / s->stats->ts_tid);
+ seq_printf(seq, " %lu blocks per transaction\n",
+ s->stats->u.run.rs_blocks / s->stats->ts_tid);
+ seq_printf(seq, " %lu logged blocks per transaction\n",
+ s->stats->u.run.rs_blocks_logged / s->stats->ts_tid);
+ return 0;
+}
+
+static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
+{
+}
+
+static struct seq_operations jbd2_seq_info_ops = {
+ .start = jbd2_seq_info_start,
+ .next = jbd2_seq_info_next,
+ .stop = jbd2_seq_info_stop,
+ .show = jbd2_seq_info_show,
+};
+
+static int jbd2_seq_info_open(struct inode *inode, struct file *file)
+{
+ journal_t *journal = PDE(inode)->data;
+ struct jbd2_stats_proc_session *s;
+ int rc, size;
+
+ s = kmalloc(sizeof(*s), GFP_KERNEL);
+ if (s == NULL)
+ return -ENOMEM;
+ size = sizeof(struct transaction_stats_s);
+ s->stats = kmalloc(size, GFP_KERNEL);
+ if (s->stats == NULL) {
+ kfree(s);
+ return -ENOMEM;
+ }
+ spin_lock(&journal->j_history_lock);
+ memcpy(s->stats, &journal->j_stats, size);
+ s->journal = journal;
+ spin_unlock(&journal->j_history_lock);
+
+ rc = seq_open(file, &jbd2_seq_info_ops);
+ if (rc == 0) {
+ struct seq_file *m = file->private_data;
+ m->private = s;
+ } else {
+ kfree(s->stats);
+ kfree(s);
+ }
+ return rc;
+
+}
+
+static int jbd2_seq_info_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+ struct jbd2_stats_proc_session *s = seq->private;
+ kfree(s->stats);
+ kfree(s);
+ return seq_release(inode, file);
+}
+
+static struct file_operations jbd2_seq_info_fops = {
+ .owner = THIS_MODULE,
+ .open = jbd2_seq_info_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = jbd2_seq_info_release,
+};
+
+static struct proc_dir_entry *proc_jbd2_stats;
+
+static void jbd2_stats_proc_init(journal_t *journal)
+{
+ char name[BDEVNAME_SIZE];
+
+ snprintf(name, sizeof(name) - 1, "%s", bdevname(journal->j_dev, name));
+ journal->j_proc_entry = proc_mkdir(name, proc_jbd2_stats);
+ if (journal->j_proc_entry) {
+ struct proc_dir_entry *p;
+ p = create_proc_entry("history", S_IRUGO,
+ journal->j_proc_entry);
+ if (p) {
+ p->proc_fops = &jbd2_seq_history_fops;
+ p->data = journal;
+ p = create_proc_entry("info", S_IRUGO,
+ journal->j_proc_entry);
+ if (p) {
+ p->proc_fops = &jbd2_seq_info_fops;
+ p->data = journal;
+ }
+ }
+ }
+}
+
+static void jbd2_stats_proc_exit(journal_t *journal)
+{
+ char name[BDEVNAME_SIZE];
+
+ snprintf(name, sizeof(name) - 1, "%s", bdevname(journal->j_dev, name));
+ remove_proc_entry("info", journal->j_proc_entry);
+ remove_proc_entry("history", journal->j_proc_entry);
+ remove_proc_entry(name, proc_jbd2_stats);
+}
+
+static void journal_init_stats(journal_t *journal)
+{
+ int size;
+
+ if (!proc_jbd2_stats)
+ return;
+
+ journal->j_history_max = 100;
+ size = sizeof(struct transaction_stats_s) * journal->j_history_max;
+ journal->j_history = kzalloc(size, GFP_KERNEL);
+ if (!journal->j_history) {
+ journal->j_history_max = 0;
+ return;
+ }
+ spin_lock_init(&journal->j_history_lock);
+}
+
/*
* Management for journal control blocks: functions to create and
* destroy journal_t structures, and to initialise and read existing
@@ -681,6 +988,9 @@ static journal_t * journal_init_common (void)
kfree(journal);
goto fail;
}
+
+ journal_init_stats(journal);
+
return journal;
fail:
return NULL;
@@ -735,6 +1045,7 @@ journal_t * jbd2_journal_init_dev(struct block_device *bdev,
journal->j_fs_dev = fs_dev;
journal->j_blk_offset = start;
journal->j_maxlen = len;
+ jbd2_stats_proc_init(journal);

bh = __getblk(journal->j_dev, start, journal->j_blocksize);
J_ASSERT(bh != NULL);
@@ -773,6 +1084,7 @@ journal_t * jbd2_journal_init_inode (struct inode *inode)

journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
journal->j_blocksize = inode->i_sb->s_blocksize;
+ jbd2_stats_proc_init(journal);

/* journal descriptor can store up to n blocks -bzzz */
n = journal->j_blocksize / sizeof(journal_block_tag_t);
@@ -1153,6 +1465,8 @@ void jbd2_journal_destroy(journal_t *journal)
brelse(journal->j_sb_buffer);
}

+ if (journal->j_proc_entry)
+ jbd2_stats_proc_exit(journal);
if (journal->j_inode)
iput(journal->j_inode);
if (journal->j_revoke)
@@ -1900,6 +2214,28 @@ static void __exit jbd2_remove_debugfs_entry(void)

#endif

+#ifdef CONFIG_PROC_FS
+
+#define JBD2_STATS_PROC_NAME "fs/jbd2"
+
+static void __init jbd2_create_jbd_stats_proc_entry(void)
+{
+ proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
+}
+
+static void __exit jbd2_remove_jbd_stats_proc_entry(void)
+{
+ if (proc_jbd2_stats)
+ remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
+}
+
+#else
+
+#define jbd2_create_jbd_stats_proc_entry() do {} while (0)
+#define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
+
+#endif
+
struct kmem_cache *jbd2_handle_cache;

static int __init journal_init_handle_cache(void)
@@ -1955,6 +2291,7 @@ static int __init journal_init(void)
if (ret != 0)
jbd2_journal_destroy_caches();
jbd2_create_debugfs_entry();
+ jbd2_create_jbd_stats_proc_entry();
return ret;
}

@@ -1966,6 +2303,7 @@ static void __exit journal_exit(void)
printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n);
#endif
jbd2_remove_debugfs_entry();
+ jbd2_remove_jbd_stats_proc_entry();
jbd2_journal_destroy_caches();
}

diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index b1fcf2b..f30802a 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -59,6 +59,8 @@ jbd2_get_transaction(journal_t *journal, transaction_t *transaction)

J_ASSERT(journal->j_running_transaction == NULL);
journal->j_running_transaction = transaction;
+ transaction->t_max_wait = 0;
+ transaction->t_start = jiffies;

return transaction;
}
@@ -85,6 +87,7 @@ static int start_this_handle(journal_t *journal, handle_t *handle)
int nblocks = handle->h_buffer_credits;
transaction_t *new_transaction = NULL;
int ret = 0;
+ unsigned long ts = jiffies;

if (nblocks > journal->j_max_transaction_buffers) {
printk(KERN_ERR "JBD: %s wants too many credits (%d > %d)\n",
@@ -217,6 +220,12 @@ repeat_locked:
/* OK, account for the buffers that this operation expects to
* use and add the handle to the running transaction. */

+ if (time_after(transaction->t_start, ts)) {
+ ts = jbd2_time_diff(ts, transaction->t_start);
+ if (ts > transaction->t_max_wait)
+ transaction->t_max_wait = ts;
+ }
+
handle->h_transaction = transaction;
transaction->t_outstanding_credits += nblocks;
transaction->t_updates++;
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index d861ffd..6856400 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -395,6 +395,16 @@ struct handle_s
};


+/*
+ * Some stats for checkpoint phase
+ */
+struct transaction_chp_stats_s {
+ unsigned long cs_chp_time;
+ unsigned long cs_forced_to_close;
+ unsigned long cs_written;
+ unsigned long cs_dropped;
+};
+
/* The transaction_t type is the guts of the journaling mechanism. It
* tracks a compound transaction through its various states:
*
@@ -532,6 +542,21 @@ struct transaction_s
spinlock_t t_handle_lock;

/*
+ * Longest time some handle had to wait for running transaction
+ */
+ unsigned long t_max_wait;
+
+ /*
+ * When transaction started
+ */
+ unsigned long t_start;
+
+ /*
+ * Checkpointing stats [j_checkpoint_sem]
+ */
+ struct transaction_chp_stats_s t_chp_stats;
+
+ /*
* Number of outstanding updates running on this transaction
* [t_handle_lock]
*/
@@ -562,6 +587,39 @@ struct transaction_s

};

+struct transaction_run_stats_s {
+ unsigned long rs_wait;
+ unsigned long rs_running;
+ unsigned long rs_locked;
+ unsigned long rs_flushing;
+ unsigned long rs_logging;
+
+ unsigned long rs_handle_count;
+ unsigned long rs_blocks;
+ unsigned long rs_blocks_logged;
+};
+
+struct transaction_stats_s {
+ int ts_type;
+ unsigned long ts_tid;
+ union {
+ struct transaction_run_stats_s run;
+ struct transaction_chp_stats_s chp;
+ } u;
+};
+
+#define JBD2_STATS_RUN 1
+#define JBD2_STATS_CHECKPOINT 2
+
+static inline unsigned long
+jbd2_time_diff(unsigned long start, unsigned long end)
+{
+ if (end >= start)
+ return end - start;
+
+ return end + (MAX_JIFFY_OFFSET - start);
+}
+
/**
* struct journal_s - The journal_s type is the concrete type associated with
* journal_t.
@@ -623,6 +681,12 @@ struct transaction_s
* @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
* number that will fit in j_blocksize
* @j_last_sync_writer: most recent pid which did a synchronous write
+ * @j_history: Buffer storing the transactions statistics history
+ * @j_history_max: Maximum number of transactions in the statistics history
+ * @j_history_cur: Current number of transactions in the statistics history
+ * @j_history_lock: Protect the transactions statistics history
+ * @j_proc_entry: procfs entry for the jbd statistics directory
+ * @j_stats: Overall statistics
* @j_private: An opaque pointer to fs-private information.
*/

@@ -815,6 +879,19 @@ struct journal_s
pid_t j_last_sync_writer;

/*
+ * Journal statistics
+ */
+ struct transaction_stats_s *j_history;
+ int j_history_max;
+ int j_history_cur;
+ /*
+ * Protect the transactions statistics history
+ */
+ spinlock_t j_history_lock;
+ struct proc_dir_entry *j_proc_entry;
+ struct transaction_stats_s j_stats;
+
+ /*
* An opaque pointer to fs-private information. ext3 puts its
* superblock pointer here
*/
--
1.5.4.rc3.31.g1271-dirty

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