bcachefs: Add more time stats for being blocked on allocator

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/alloc_foreground.c

@@ -246,6 +246,10 @@ struct open_bucket *bch2_bucket_alloc(struct bch_fs *c, struct bch_dev *ca,
 	if (unlikely(c->open_buckets_nr_free <= open_buckets_reserved(reserve))) {
 		if (cl)
 			closure_wait(&c->open_buckets_wait, cl);
+
+		if (!c->blocked_allocate_open_bucket)
+			c->blocked_allocate_open_bucket = local_clock();
+
 		spin_unlock(&c->freelist_lock);
 		trace_open_bucket_alloc_fail(ca, reserve);
 		return ERR_PTR(-OPEN_BUCKETS_EMPTY);
@@ -276,6 +280,9 @@ struct open_bucket *bch2_bucket_alloc(struct bch_fs *c, struct bch_dev *ca,
 	if (cl)
 		closure_wait(&c->freelist_wait, cl);
 
+	if (!c->blocked_allocate)
+		c->blocked_allocate = local_clock();
+
 	spin_unlock(&c->freelist_lock);
 
 	trace_bucket_alloc_fail(ca, reserve);
@@ -301,6 +308,20 @@ struct open_bucket *bch2_bucket_alloc(struct bch_fs *c, struct bch_dev *ca,
 	bucket_io_clock_reset(c, ca, bucket, WRITE);
 	spin_unlock(&ob->lock);
 
+	if (c->blocked_allocate_open_bucket) {
+		bch2_time_stats_update(
+			&c->times[BCH_TIME_blocked_allocate_open_bucket],
+			c->blocked_allocate_open_bucket);
+		c->blocked_allocate_open_bucket = 0;
+	}
+
+	if (c->blocked_allocate) {
+		bch2_time_stats_update(
+			&c->times[BCH_TIME_blocked_allocate],
+			c->blocked_allocate);
+		c->blocked_allocate = 0;
+	}
+
 	spin_unlock(&c->freelist_lock);
 
 	bch2_wake_allocator(ca);

fs/bcachefs/bcachefs.h

@@ -302,8 +302,10 @@ do {									\
 	x(data_promote)				\
 	x(journal_write)			\
 	x(journal_delay)			\
-	x(journal_blocked)			\
-	x(journal_flush_seq)
+	x(journal_flush_seq)			\
+	x(blocked_journal)			\
+	x(blocked_allocate)			\
+	x(blocked_allocate_open_bucket)
 
 enum bch_time_stats {
 #define x(name) BCH_TIME_##name,
@@ -653,6 +655,8 @@ struct bch_fs {
 	/* ALLOCATOR */
 	spinlock_t		freelist_lock;
 	struct closure_waitlist	freelist_wait;
+	u64			blocked_allocate;
+	u64			blocked_allocate_open_bucket;
 	u8			open_buckets_freelist;
 	u8			open_buckets_nr_free;
 	struct closure_waitlist	open_buckets_wait;

fs/bcachefs/super.c

@@ -596,7 +596,7 @@ static struct bch_fs *bch2_fs_alloc(struct bch_sb *sb, struct bch_opts opts)
 
 	c->journal.write_time	= &c->times[BCH_TIME_journal_write];
 	c->journal.delay_time	= &c->times[BCH_TIME_journal_delay];
-	c->journal.blocked_time	= &c->times[BCH_TIME_journal_blocked];
+	c->journal.blocked_time	= &c->times[BCH_TIME_blocked_journal];
 	c->journal.flush_seq_time = &c->times[BCH_TIME_journal_flush_seq];
 
 	bch2_fs_btree_cache_init_early(&c->btree_cache);