Managing large indirect userdata

[Mark Hamburg <mhamburg@...>]

Is there any standard advice on how to manage large, indirect (i.e., the
userdata itself stores a pointer to a separate block) userdata? I sometimes
find that my application is choking on large, cached pixmaps and textures. I
need to have something happen to drive the garbage collector forward or
prompt collection in response to the existence of these objects.

Mark