make coroutine_pool weak would be better

lualib/skynet.lua

@@ -95,7 +95,7 @@ end
 
 -- coroutine reuse
 
-local coroutine_pool = {}
+local coroutine_pool = setmetatable({}, { __mode = "kv" })
 
 local function co_create(f)
 	local co = table.remove(coroutine_pool)
@@ -661,15 +661,10 @@ function skynet.memlimit(bytes)
 	skynet.memlimit = nil	-- set only once
 end
 
-local function clear_pool()
-	coroutine_pool = {}
-end
-
 -- Inject internal debug framework
 local debug = require "skynet.debug"
 debug(skynet, {
 	dispatch = skynet.dispatch_message,
-	clear = clear_pool,
 	suspend = suspend,
 })
 

lualib/skynet/debug.lua

@@ -20,7 +20,6 @@ function dbgcmd.MEM()
 end
 
 function dbgcmd.GC()
-	export.clear()
 	collectgarbage "collect"
 end