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=829253 (3239.3 MB free)
iter 1     faults=1 v_free_count=829253 (delta_from_start=+0 pages = 0.0 MB consumed)
iter 50    faults=50 v_free_count=819143 (delta_from_start=-10110 pages = 39.5 MB consumed)
iter 100   faults=100 v_free_count=810110 (delta_from_start=-19143 pages = 74.8 MB consumed)
iter 150   faults=150 v_free_count=799898 (delta_from_start=-29355 pages = 114.7 MB consumed)
iter 200   faults=200 v_free_count=790275 (delta_from_start=-38978 pages = 152.3 MB consumed)
iter 250   faults=250 v_free_count=779474 (delta_from_start=-49779 pages = 194.4 MB consumed)
iter 300   faults=300 v_free_count=770244 (delta_from_start=-59009 pages = 230.5 MB consumed)

end:   v_free_count=770244  consumed=59009 pages = 230.5 MB
expected if leak real: 228.9 MB; expected if fixed: ~0 MB
faults=300/300