Wired memory consumes almost all my memory recently

Hi current_at_,

I'm experiencing some problems with memory on r358410.

I'm building a lot of ports in poudriere for testing purposes, which is 
very a resource-intensive operation. After a couple of hours of such a 
workload, the machine starts to become much less responsive (e.g., it 
takes a couple seconds to start a new tmux pane). When I run top I would 
always see that almost all my memory is wired (15G), swap reports a 
couple of hundreds megabytes being used, and the free memory is less 
than 100M.

If I kill all my desktop processes like Firefox and Thunderbird (it 
takes a couple of minutes to complete this task!) then the machine 
becomes responsive again, still having maybe a couple hundreds of 
megabytes of free memory for me.

I thought that maybe this is an ARC problem (I'm using ZFS) but it 
didn't help to restrict ARC to 8G by setting sysctl 
vfs.zfs.arc_max=8517738496.

I think that I've never experienced similar problems before.

Cheers,

Mateusz Piotrowski