jbd2: Change j_state_lock to be a rwlock_t
Lockstat reports have shown that j_state_lock is a major source of
lock contention, especially on systems with more than 4 CPU cores. So
change it to be a read/write spinlock.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index a79d334..e7bf0fd 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -142,7 +142,7 @@
/*
* And now, wait forever for commit wakeup events.
*/
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
loop:
if (journal->j_flags & JBD2_UNMOUNT)
@@ -153,10 +153,10 @@
if (journal->j_commit_sequence != journal->j_commit_request) {
jbd_debug(1, "OK, requests differ\n");
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
del_timer_sync(&journal->j_commit_timer);
jbd2_journal_commit_transaction(journal);
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
goto loop;
}
@@ -168,9 +168,9 @@
* be already stopped.
*/
jbd_debug(1, "Now suspending kjournald2\n");
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
refrigerator();
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
} else {
/*
* We assume on resume that commits are already there,
@@ -190,9 +190,9 @@
if (journal->j_flags & JBD2_UNMOUNT)
should_sleep = 0;
if (should_sleep) {
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
schedule();
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
}
finish_wait(&journal->j_wait_commit, &wait);
}
@@ -210,7 +210,7 @@
goto loop;
end_loop:
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
del_timer_sync(&journal->j_commit_timer);
journal->j_task = NULL;
wake_up(&journal->j_wait_done_commit);
@@ -233,16 +233,16 @@
static void journal_kill_thread(journal_t *journal)
{
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
journal->j_flags |= JBD2_UNMOUNT;
while (journal->j_task) {
wake_up(&journal->j_wait_commit);
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
}
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
}
/*
@@ -452,7 +452,7 @@
{
int left = journal->j_free;
- assert_spin_locked(&journal->j_state_lock);
+ /* assert_spin_locked(&journal->j_state_lock); */
/*
* Be pessimistic here about the number of those free blocks which
@@ -497,9 +497,9 @@
{
int ret;
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
ret = __jbd2_log_start_commit(journal, tid);
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
return ret;
}
@@ -518,7 +518,7 @@
transaction_t *transaction = NULL;
tid_t tid;
- spin_lock(&journal->j_state_lock);
+ read_lock(&journal->j_state_lock);
if (journal->j_running_transaction && !current->journal_info) {
transaction = journal->j_running_transaction;
__jbd2_log_start_commit(journal, transaction->t_tid);
@@ -526,12 +526,12 @@
transaction = journal->j_committing_transaction;
if (!transaction) {
- spin_unlock(&journal->j_state_lock);
+ read_unlock(&journal->j_state_lock);
return 0; /* Nothing to retry */
}
tid = transaction->t_tid;
- spin_unlock(&journal->j_state_lock);
+ read_unlock(&journal->j_state_lock);
jbd2_log_wait_commit(journal, tid);
return 1;
}
@@ -545,7 +545,7 @@
{
int ret = 0;
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
if (journal->j_running_transaction) {
tid_t tid = journal->j_running_transaction->t_tid;
@@ -564,7 +564,7 @@
*ptid = journal->j_committing_transaction->t_tid;
ret = 1;
}
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
return ret;
}
@@ -576,26 +576,24 @@
{
int err = 0;
+ read_lock(&journal->j_state_lock);
#ifdef CONFIG_JBD2_DEBUG
- spin_lock(&journal->j_state_lock);
if (!tid_geq(journal->j_commit_request, tid)) {
printk(KERN_EMERG
"%s: error: j_commit_request=%d, tid=%d\n",
__func__, journal->j_commit_request, tid);
}
- spin_unlock(&journal->j_state_lock);
#endif
- spin_lock(&journal->j_state_lock);
while (tid_gt(tid, journal->j_commit_sequence)) {
jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
tid, journal->j_commit_sequence);
wake_up(&journal->j_wait_commit);
- spin_unlock(&journal->j_state_lock);
+ read_unlock(&journal->j_state_lock);
wait_event(journal->j_wait_done_commit,
!tid_gt(tid, journal->j_commit_sequence));
- spin_lock(&journal->j_state_lock);
+ read_lock(&journal->j_state_lock);
}
- spin_unlock(&journal->j_state_lock);
+ read_unlock(&journal->j_state_lock);
if (unlikely(is_journal_aborted(journal))) {
printk(KERN_EMERG "journal commit I/O error\n");
@@ -612,7 +610,7 @@
{
unsigned long blocknr;
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
J_ASSERT(journal->j_free > 1);
blocknr = journal->j_head;
@@ -620,7 +618,7 @@
journal->j_free--;
if (journal->j_head == journal->j_last)
journal->j_head = journal->j_first;
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
return jbd2_journal_bmap(journal, blocknr, retp);
}
@@ -840,7 +838,7 @@
mutex_init(&journal->j_checkpoint_mutex);
spin_lock_init(&journal->j_revoke_lock);
spin_lock_init(&journal->j_list_lock);
- spin_lock_init(&journal->j_state_lock);
+ rwlock_init(&journal->j_state_lock);
journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
journal->j_min_batch_time = 0;
@@ -1106,14 +1104,14 @@
set_buffer_uptodate(bh);
}
- spin_lock(&journal->j_state_lock);
+ read_lock(&journal->j_state_lock);
jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n",
journal->j_tail, journal->j_tail_sequence, journal->j_errno);
sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
sb->s_start = cpu_to_be32(journal->j_tail);
sb->s_errno = cpu_to_be32(journal->j_errno);
- spin_unlock(&journal->j_state_lock);
+ read_unlock(&journal->j_state_lock);
BUFFER_TRACE(bh, "marking dirty");
mark_buffer_dirty(bh);
@@ -1134,12 +1132,12 @@
* any future commit will have to be careful to update the
* superblock again to re-record the true start of the log. */
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
if (sb->s_start)
journal->j_flags &= ~JBD2_FLUSHED;
else
journal->j_flags |= JBD2_FLUSHED;
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
}
/*
@@ -1551,7 +1549,7 @@
transaction_t *transaction = NULL;
unsigned long old_tail;
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
/* Force everything buffered to the log... */
if (journal->j_running_transaction) {
@@ -1564,10 +1562,10 @@
if (transaction) {
tid_t tid = transaction->t_tid;
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
jbd2_log_wait_commit(journal, tid);
} else {
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
}
/* ...and flush everything in the log out to disk. */
@@ -1591,12 +1589,12 @@
* the magic code for a fully-recovered superblock. Any future
* commits of data to the journal will restore the current
* s_start value. */
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
old_tail = journal->j_tail;
journal->j_tail = 0;
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
jbd2_journal_update_superblock(journal, 1);
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
journal->j_tail = old_tail;
J_ASSERT(!journal->j_running_transaction);
@@ -1604,7 +1602,7 @@
J_ASSERT(!journal->j_checkpoint_transactions);
J_ASSERT(journal->j_head == journal->j_tail);
J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
return 0;
}
@@ -1668,12 +1666,12 @@
printk(KERN_ERR "Aborting journal on device %s.\n",
journal->j_devname);
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
journal->j_flags |= JBD2_ABORT;
transaction = journal->j_running_transaction;
if (transaction)
__jbd2_log_start_commit(journal, transaction->t_tid);
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
}
/* Soft abort: record the abort error status in the journal superblock,
@@ -1758,12 +1756,12 @@
{
int err;
- spin_lock(&journal->j_state_lock);
+ read_lock(&journal->j_state_lock);
if (journal->j_flags & JBD2_ABORT)
err = -EROFS;
else
err = journal->j_errno;
- spin_unlock(&journal->j_state_lock);
+ read_unlock(&journal->j_state_lock);
return err;
}
@@ -1778,12 +1776,12 @@
{
int err = 0;
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
if (journal->j_flags & JBD2_ABORT)
err = -EROFS;
else
journal->j_errno = 0;
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
return err;
}
@@ -1796,10 +1794,10 @@
*/
void jbd2_journal_ack_err(journal_t *journal)
{
- spin_lock(&journal->j_state_lock);
+ write_lock(&journal->j_state_lock);
if (journal->j_errno)
journal->j_flags |= JBD2_ACK_ERR;
- spin_unlock(&journal->j_state_lock);
+ write_unlock(&journal->j_state_lock);
}
int jbd2_journal_blocks_per_page(struct inode *inode)