GTT memory not being freed, resulting in high system RAM being used, and often OOMs
Right now my system is sitting at 92% RAM usage (of 16GB) and 100% swap usage (1GB). Radeontop lists an absolutely massive GTT size of 7663MB, of which only around ~4000MB is currently being used (and that number could certainly go down further once I close out more browser tabs, since they seem to be the main user of VRAM right now). As far as I can tell, there's no way to force the kernel driver to reduce the GTT size, and it certainly doesn't appear to be happening automatically.