DRM (Direct Rendering, not Digital Rights) on DragonFly will normally eat all the memory it thinks it needs. However, vm.dma_reserved can now be set to a fixed limit in /boot/loader.conf. By default, vm.dma_reserved on DragonFly is set to 16M, and can be set higher. I think this is necessary when running higher-resolution screens… Don’t quote me on that, though.
A running description of activity related to DragonFly BSD.
I’d advise 24M for a 1440×900 Macbook Air. After experimenting with that. It is unnoticable in most cases but seems to leave artifacts in graphic intense applications such as blender. I’m not sure about things like compiz or gimp, but I run the blender rendering on the server.
Anyone care to explain what exactly runs through that buffer?
Don’t know about the buffer but can you tell what is video driver you using?