IDirect3DDevice9::EvictManagedResources
Dx9的文档上有这样一句话：
When entering a new level in a game, your application might need to flush all managed textures from video memory (by calling IDirect3DDevice9::EvictManagedResources).
When entering a new level in a game, your application might need to flush all managed textures from video memory (by calling IDirect3DDevice9::EvictManagedResources).
