bcachefs: Add actual tracepoints for transaction restarts

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

fs/bcachefs/btree_cache.c

@@ -734,6 +734,8 @@ struct btree *bch2_btree_node_get(struct bch_fs *c, struct btree_iter *iter,
 				goto retry;
 
 			trans_restart();
+			trace_trans_restart_btree_node_reused(c,
+						iter->trans->ip);
 			return ERR_PTR(-EINTR);
 		}
 	}

fs/bcachefs/btree_iter.c

@@ -252,12 +252,15 @@ bool __bch2_btree_node_lock(struct btree *b, struct bpos pos,
 		}
 	}
 
-	if (ret)
-		__btree_node_lock_type(iter->trans->c, b, type);
-	else
+	if (unlikely(!ret)) {
 		trans_restart();
+		trace_trans_restart_would_deadlock(iter->trans->c,
+						   iter->trans->ip);
+		return false;
+	}
 
-	return ret;
+	__btree_node_lock_type(iter->trans->c, b, type);
+	return true;
 }
 
 /* Btree iterator locking: */
@@ -1695,6 +1698,7 @@ static int btree_trans_realloc_iters(struct btree_trans *trans,
 
 	if (trans->iters_live) {
 		trans_restart();
+		trace_trans_restart_iters_realloced(trans->c, trans->ip);
 		return -EINTR;
 	}
 
@@ -1863,6 +1867,7 @@ void *bch2_trans_kmalloc(struct btree_trans *trans,
 
 		if (old_bytes) {
 			trans_restart();
+			trace_trans_restart_mem_realloced(trans->c, trans->ip);
 			return ERR_PTR(-EINTR);
 		}
 	}
@@ -1939,6 +1944,7 @@ void bch2_trans_init(struct btree_trans *trans, struct bch_fs *c)
 	memset(trans, 0, offsetof(struct btree_trans, iters_onstack));
 
 	trans->c		= c;
+	trans->ip		= _RET_IP_;
 	trans->size		= ARRAY_SIZE(trans->iters_onstack);
 	trans->iters		= trans->iters_onstack;
 	trans->updates		= trans->updates_onstack;

fs/bcachefs/btree_types.h

@@ -267,6 +267,7 @@ struct btree_insert_entry {
 
 struct btree_trans {
 	struct bch_fs		*c;
+	unsigned long		ip;
 	size_t			nr_restarts;
 	u64			commit_start;
 

fs/bcachefs/btree_update_leaf.c

@@ -440,6 +440,7 @@ static int bch2_trans_journal_preres_get(struct btree_trans *trans)
 
 	if (!bch2_btree_trans_relock(trans)) {
 		trans_restart(" (iter relock after journal preres get blocked)");
+		trace_trans_restart_journal_preres_get(c, trans->ip);
 		return -EINTR;
 	}
 
@@ -564,6 +565,7 @@ static inline int do_btree_insert_at(struct btree_trans *trans,
 	if (race_fault()) {
 		ret = -EINTR;
 		trans_restart(" (race)");
+		trace_trans_restart_fault_inject(c, trans->ip);
 		goto out;
 	}
 
@@ -680,6 +682,7 @@ int bch2_trans_commit_error(struct btree_trans *trans,
 		 */
 		if (!ret || (flags & BTREE_INSERT_NOUNLOCK)) {
 			trans_restart(" (split)");
+			trace_trans_restart_btree_node_split(c, trans->ip);
 			ret = -EINTR;
 		}
 		break;
@@ -699,6 +702,7 @@ int bch2_trans_commit_error(struct btree_trans *trans,
 			return 0;
 
 		trans_restart(" (iter relock after marking replicas)");
+		trace_trans_restart_mark_replicas(c, trans->ip);
 		ret = -EINTR;
 		break;
 	case BTREE_INSERT_NEED_JOURNAL_RES:
@@ -712,6 +716,7 @@ int bch2_trans_commit_error(struct btree_trans *trans,
 			return 0;
 
 		trans_restart(" (iter relock after journal res get blocked)");
+		trace_trans_restart_journal_res_get(c, trans->ip);
 		ret = -EINTR;
 		break;
 	default:
@@ -724,6 +729,7 @@ int bch2_trans_commit_error(struct btree_trans *trans,
 
 		if (ret2) {
 			trans_restart(" (traverse)");
+			trace_trans_restart_traverse(c, trans->ip);
 			return ret2;
 		}
 
@@ -735,6 +741,7 @@ int bch2_trans_commit_error(struct btree_trans *trans,
 			return 0;
 
 		trans_restart(" (atomic)");
+		trace_trans_restart_atomic(c, trans->ip);
 	}
 
 	return ret;

fs/bcachefs/trace.h

@@ -499,6 +499,78 @@ TRACE_EVENT(copygc,
 		__entry->buckets_moved, __entry->buckets_not_moved)
 );
 
+DECLARE_EVENT_CLASS(transaction_restart,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip),
+
+	TP_STRUCT__entry(
+		__array(char,			name,	16)
+		__field(unsigned long,		ip	)
+	),
+
+	TP_fast_assign(
+		memcpy(__entry->name, c->name, 16);
+		__entry->ip = ip;
+	),
+
+	TP_printk("%pS", (void *) __entry->ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_btree_node_reused,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_would_deadlock,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_iters_realloced,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_mem_realloced,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_journal_res_get,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_journal_preres_get,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_mark_replicas,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_fault_inject,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_btree_node_split,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_traverse,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
+DEFINE_EVENT(transaction_restart,	trans_restart_atomic,
+	TP_PROTO(struct bch_fs *c, unsigned long ip),
+	TP_ARGS(c, ip)
+);
+
 #endif /* _TRACE_BCACHEFS_H */
 
 /* This part must be outside protection */