Increase default emerge queue limits and limit enqueue requests for a…

…ctive blocks.

builtin/settingtypes.txt

@@ -2152,15 +2152,15 @@ chunksize (Chunk size) int 5
 enable_mapgen_debug_info (Mapgen debug) bool false
 
 #    Maximum number of blocks that can be queued for loading.
-emergequeue_limit_total (Absolute limit of queued blocks to emerge) int 512
+emergequeue_limit_total (Absolute limit of queued blocks to emerge) int 1024
 
 #    Maximum number of blocks to be queued that are to be loaded from file.
 #    This limit is enforced per player.
-emergequeue_limit_diskonly (Per-player limit of queued blocks load from disk) int 64
+emergequeue_limit_diskonly (Per-player limit of queued blocks load from disk) int 128
 
 #    Maximum number of blocks to be queued that are to be generated.
 #    This limit is enforced per player.
-emergequeue_limit_generate (Per-player limit of queued blocks to generate) int 64
+emergequeue_limit_generate (Per-player limit of queued blocks to generate) int 128
 
 #    Number of emerge threads to use.
 #    Value 0:

src/defaultsettings.cpp

@@ -396,9 +396,9 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("debug_log_level", "action");
 	settings->setDefault("debug_log_size_max", "50");
 	settings->setDefault("chat_log_level", "error");
-	settings->setDefault("emergequeue_limit_total", "512");
-	settings->setDefault("emergequeue_limit_diskonly", "64");
-	settings->setDefault("emergequeue_limit_generate", "64");
+	settings->setDefault("emergequeue_limit_total", "1024");
+	settings->setDefault("emergequeue_limit_diskonly", "128");
+	settings->setDefault("emergequeue_limit_generate", "128");
 	settings->setDefault("num_emerge_threads", "1");
 	settings->setDefault("secure.enable_security", "true");
 	settings->setDefault("secure.trusted_mods", "");

src/emerge.cpp

@@ -426,6 +426,10 @@ bool EmergeManager::pushBlockEmergeData(
 				m_qlimit_generate : m_qlimit_diskonly;
 			if (count_peer >= qlimit_peer)
 				return false;
+		} else {
+			// limit block enqueue requests for active blocks to 1/2 of total
+			if (count_peer * 2 >= m_qlimit_total)
+				return false;
 		}
 	}