physical memory allocator in DragonFly BSD

[Stéphanie Ouillon]

Hello,

Venkatesh Srinivas made a comment on my gsoc application about 
implementing virtio drivers ( by the way, thank you about it ! I added 
some lines and time for the balloon driver ).
I copy it :
"Just a warning -- the virtio balloon driver will likely involve a good 
amount of porting work; the NetBSD UVM is rather different than the DFly 
VM. The mechanism by which the balloon consumes "physical" memory will 
likely be different. On NetBSD, it probably uses something like 
uvm_pglistalloc()... I don't think we have a good contiguous physical 
memory allocator, so you might have to be careful."

When NetBSD uses uvm_pglistalloc and uvm_pglistfree (I checked the 
code), DragonFly BSD will likely use contigmalloc and contigfree (like 
in FreeBSD) to deal with contiguous physical allocation.
Well, I searched for some information, but could you explain me why I 
should be cautious with the physical memory allocation on DragonFly BSD, 
do you have encoutered any problem with it ?


Thank you !

Stéphanie