Scripting: use mstime() and mstime_t for lua_time_start.

server.lua_time_start is expressed in milliseconds. Use mstime_t instead
of long long, and populate it with mstime() instead of ustime()/1000.

Functionally identical but more natural.

src/redis.h

@@ -799,8 +799,8 @@ struct redisServer {
     redisClient *lua_client;   /* The "fake client" to query Redis from Lua */
     redisClient *lua_caller;   /* The client running EVAL right now, or NULL */
     dict *lua_scripts;         /* A dictionary of SHA1 -> Lua scripts */
-    long long lua_time_limit;  /* Script timeout in seconds */
-    long long lua_time_start;  /* Start time of script */
+    mstime_t lua_time_limit;  /* Script timeout in milliseconds */
+    mstime_t lua_time_start;  /* Start time of script, milliseconds time */
     int lua_write_dirty;  /* True if a write command was called during the
                              execution of the current script. */
     int lua_random_dirty; /* True if a random command was called during the

src/scripting.c

@@ -441,7 +441,7 @@ void luaMaskCountHook(lua_State *lua, lua_Debug *ar) {
     REDIS_NOTUSED(ar);
     REDIS_NOTUSED(lua);
 
-    elapsed = (ustime()/1000) - server.lua_time_start;
+    elapsed = mstime() - server.lua_time_start;
     if (elapsed >= server.lua_time_limit && server.lua_timedout == 0) {
         redisLog(REDIS_WARNING,"Lua slow script detected: still in execution after %lld milliseconds. You can try killing the script using the SCRIPT KILL command.",elapsed);
         server.lua_timedout = 1;
@@ -900,7 +900,7 @@ void evalGenericCommand(redisClient *c, int evalsha) {
      * We set the hook only if the time limit is enabled as the hook will
      * make the Lua script execution slower. */
     server.lua_caller = c;
-    server.lua_time_start = ustime()/1000;
+    server.lua_time_start = mstime();
     server.lua_kill = 0;
     if (server.lua_time_limit > 0 && server.masterhost == NULL) {
         lua_sethook(lua,luaMaskCountHook,LUA_MASKCOUNT,100000);