LUA memory issue

[atharti]

Hey, like halfyear ago i notcied that when i farm mobs in public dungeon my LUA memory usage grows unendingly, usually i have about 450mb used, and i have like hunded addons. One time it reached 2 GBs (was farming for hours), well problem is not that it takes much, problem is that game start lagging. My FPS goes from stable 60 to 10 overtime, and mobs stop rendering correctly like i approach the spot use skill, already see the damage numbers but not the mobs, also other textures get scuffed. Reloading UI resets LUA memory to normal, or a relog. Its super annoying, it grows like 10mb per minute and only happening when i farm mobs in public dungeon, in blackrose prison exp runs everything is smooth for some reason.
So id like to ask you, whats happening? Is it some certain addon that works in a wrong way? Or its just how its should be? Would like to hear any advices in general or how to find that bad addon. I tried disabling massive ones like interface etc but it didnt help, general LUA memory usage goes low but it still grows.