differences between M_CACHE, M_DEVBUF, M_TEMP

[Bharma Ji]

Hi
I am trying to understand the difference in these three different memories.
Code comments in kern_malloc.c says that M_DEVBUF should be used for device
driver. I didn't however see any major difference between the three
memories. Can a device theoretically take up memory from  M_TEMP (or
M_CACHE) segment? Similary can device drivers using M_DEVBUF also allocate
from M_CACHE / M_TEMP if needed.