Kernel memory leak with x11/nvidia-driver

I just set up a new desktop running head with x11/nvidia-driver.  I've
discovered a memory leak where pages disappear from the queues, never to
return.  Specifically, the total of
    v_active_count
    v_inactive_count
    v_wire_count
    v_cache_count
    v_free_count
drops, eventually becoming /much/ less than v_page_count.  After leaving
xscreensaver running overnight, cycling the saver every 10 minutes, the
system was unusable, because it only had a few MB of memory.  (It has 8
GB physical.)

I see this on head from a few days ago.  I do /not/ see it on stable/10
from a few days ago.

Just starting and stopping Xorg eats pages.  Starting and stopping X
apps also eats pages, some more than others.  Some screensavers ate a
lot more memory than others.  This is why I suspect the nvidia driver is
the trigger.  I rebuilt the x11/nvidia-driver port, but that didn't help.

I would love to bisect to find the offending commit, but that would take
a /lot/ of time, partly because I don't have a lower bound other than
the stable/10 branch point (since this is a new installation).

Does anyone know of any specific commits that could be suspicious? 
There have been several big changes in VM (e.g. more NUMA support, cache
page elimination).  Do any of those changes seem more likely?  I'll take
even a hunch at this point.  :)  Are there other areas I should look at?

Is anyone running an older revision of head with the nvidia driver and
doesn't see this problem?  That would narrow the range for bisection.

I should mention that I'm running with D3162* in my tree for NIC
support, but there is no relationship between the leak and network
activity, and I don't see the leak on stable/10+D3162.

Thanks in advance,

Eric

* https://reviews.freebsd.org/D3162