DF-2309 usrbufs leak loop: nmsgs=100000 iters=300
per-call leak if real: 800000 bytes; total if real: 228.9 MB
start: v_free_count=769799 (3007.0 MB free)
iter 1     faults=1 v_free_count=769799 (delta_from_start=+0 pages = 0.0 MB consumed)
iter 50    faults=50 v_free_count=769273 (delta_from_start=-526 pages = 2.1 MB consumed)
iter 100   faults=100 v_free_count=769273 (delta_from_start=-526 pages = 2.1 MB consumed)
iter 150   faults=150 v_free_count=769593 (delta_from_start=-206 pages = 0.8 MB consumed)
iter 200   faults=200 v_free_count=769273 (delta_from_start=-526 pages = 2.1 MB consumed)
iter 250   faults=250 v_free_count=769273 (delta_from_start=-526 pages = 2.1 MB consumed)
iter 300   faults=300 v_free_count=769273 (delta_from_start=-526 pages = 2.1 MB consumed)

end:   v_free_count=769273  consumed=526 pages = 2.1 MB
expected if leak real: 228.9 MB; expected if fixed: ~0 MB
faults=300/300