Need help tracking down memory consumption increase

I'm seeing a slow increase in memory consumption and I'm trying to narrow down the possible causes.

In my test, I got the system into steady-state and then started monitoring /proc/meminfo.

After 14 hrs:
MemFree had dropped by 594MB.
Active + Inactive + Slab increased by 594MB
Buffers + Cached + AnonPages + Mapped + Slab increased by 290MB

The other categories in /proc/meminfo didn't change significantly.

I've done some experimenting and it seems that pages allocated in the kernel via alloc_page() and friends don't show up in /proc/meminfo except that they're deducted from the MemFree category. Specifically, they don't seem to show up in the Active/Inactive category. Can someone confirm this?

Given the above, what types of pages are in Active/Inactive other than Buffers + Cached + AnonPages + Mapped?

Thanks,

Chris