ld: Replace list of outgoing_txs with a hash table

We had a quadratic check when processing a block, and this just
reduces it to be linear. Combined with the previous fix of adding txs
multiple times, this should speed up block processing considerably.

Author: cdecker

lightningd/chaintopology.c

@@ -53,13 +53,7 @@ static void next_topology_timer(struct chain_topology *topo)
 static bool we_broadcast(const struct chain_topology *topo,
 			 const struct bitcoin_txid *txid)
 {
-	const struct outgoing_tx *otx;
-
-	list_for_each(&topo->outgoing_txs, otx, list) {
-		if (bitcoin_txid_eq(&otx->txid, txid))
-			return true;
-	}
-	return false;
+	return outgoing_tx_map_get(&topo->outgoing_txs, txid) != NULL;
 }
 
 static void filter_block_txs(struct chain_topology *topo, struct block *b)
@@ -160,13 +154,16 @@ static void rebroadcast_txs(struct chain_topology *topo)
 	/* Copy txs now (peers may go away, and they own txs). */
 	struct txs_to_broadcast *txs;
 	struct outgoing_tx *otx;
+	struct outgoing_tx_map_iter it;
 
 	txs = tal(topo, struct txs_to_broadcast);
 	txs->cmd_id = tal_arr(txs, const char *, 0);
 
 	/* Put any txs we want to broadcast in ->txs. */
 	txs->txs = tal_arr(txs, const char *, 0);
-	list_for_each(&topo->outgoing_txs, otx, list) {
+
+	for (otx = outgoing_tx_map_first(&topo->outgoing_txs, &it); otx;
+	     otx = outgoing_tx_map_next(&topo->outgoing_txs, &it)) {
 		if (wallet_transaction_height(topo->ld->wallet, &otx->txid))
 			continue;
 
@@ -180,9 +177,9 @@ static void rebroadcast_txs(struct chain_topology *topo)
 	broadcast_remainder(topo->bitcoind, true, "", txs);
 }
 
-static void destroy_outgoing_tx(struct outgoing_tx *otx)
+static void destroy_outgoing_tx(struct outgoing_tx *otx, struct chain_topology *topo)
 {
-	list_del(&otx->list);
+	outgoing_tx_map_del(&topo->outgoing_txs, otx);
 }
 
 static void clear_otx_channel(struct channel *channel, struct outgoing_tx *otx)
@@ -218,8 +215,8 @@ static void broadcast_done(struct bitcoind *bitcoind,
 	} else {
 		/* For continual rebroadcasting, until channel freed. */
 		tal_steal(otx->channel, otx);
-		list_add_tail(&bitcoind->ld->topology->outgoing_txs, &otx->list);
-		tal_add_destructor(otx, destroy_outgoing_tx);
+		outgoing_tx_map_add(&bitcoind->ld->topology->outgoing_txs, notleak(otx));
+		tal_add_destructor2(otx, destroy_outgoing_tx, bitcoind->ld->topology);
 	}
 }
 
@@ -941,13 +938,17 @@ u32 feerate_max(struct lightningd *ld, bool *unknown)
 static void destroy_chain_topology(struct chain_topology *topo)
 {
 	struct outgoing_tx *otx;
-
-	while ((otx = list_pop(&topo->outgoing_txs, struct outgoing_tx, list)))
+	struct outgoing_tx_map_iter it;
+	for (otx = outgoing_tx_map_first(&topo->outgoing_txs, &it); otx;
+	     otx = outgoing_tx_map_next(&topo->outgoing_txs, &it)) {
+		tal_del_destructor2(otx, destroy_outgoing_tx, topo);
 		tal_free(otx);
+	}
 
 	/* htable uses malloc, so it would leak here */
 	txwatch_hash_clear(&topo->txwatches);
 	txowatch_hash_clear(&topo->txowatches);
+	outgoing_tx_map_clear(&topo->outgoing_txs);
 	block_map_clear(&topo->block_map);
 }
 
@@ -957,7 +958,7 @@ struct chain_topology *new_topology(struct lightningd *ld, struct log *log)
 
 	topo->ld = ld;
 	block_map_init(&topo->block_map);
-	list_head_init(&topo->outgoing_txs);
+	outgoing_tx_map_init(&topo->outgoing_txs);
 	txwatch_hash_init(&topo->txwatches);
 	txowatch_hash_init(&topo->txowatches);
 	topo->log = log;

lightningd/chaintopology.h

@@ -18,7 +18,6 @@ struct txwatch;
 
 /* Off topology->outgoing_txs */
 struct outgoing_tx {
-	struct list_node list;
 	struct channel *channel;
 	const char *hextx;
 	struct bitcoin_txid txid;
@@ -117,7 +116,7 @@ struct chain_topology {
 	struct oneshot *extend_timer, *updatefee_timer;
 
 	/* Bitcoin transactions we're broadcasting */
-	struct list_head outgoing_txs;
+	struct outgoing_tx_map outgoing_txs;
 
 	/* Transactions/txos we are watching. */
 	struct txwatch_hash txwatches;