add comments

@@ -37,7 +37,7 @@ function  toboolean(str,default)
   end
 end
 
-
+---- read config file: http://git.yoho.cn/ops/configuration/blob/master/nginx_common_conf.yml
 local query_common_conf=function()
   local httpc = http:new()
 
@@ -65,7 +65,7 @@ local query_common_conf=function()
   end
 end
 
-
+--- read config file: http://git.yoho.cn/ops/configuration/blob/master/nginx_limit_api.yml
 -->>begin: query rate limit config function definition
 local query_rate_limit_conf=function()
    local httpc = http:new()
@@ -105,7 +105,7 @@ end
 --<<end: query rate limit config function definition
 
 
-
+-- read config file http://git.yoho.cn/ops/configuration/blob/master/nginx_limit_ip.yml
 -->>begin: query limit ip access config function definition
 local query_limit_ip_access_conf=function()
    local httpc = http:new()
@@ -268,7 +268,7 @@ timer_handler(true,25,query_limit_ip_access_conf,0)
 timer_handler(true,30,query_common_conf,0)
 
 
--- every worker timing schedule configs from share cache
+-- every worker read global configs from share cache into local cache
 function rate_limit_conf_to_worker()
     local t=lua_context.lua_conf_cache:get("api_rate_limit_conf")
     if t then
@@ -308,6 +308,7 @@ timer_handler(true,2,limit_ip_access_conf_to_worker)
 timer_handler(true,2,query_common_conf_to_worker)
 
 
+--- broadcast set_peer_down to all workers.
 local  stream_ctx={}
 function updownstream()
   local keys=upstream_cache:get_keys()