strange 'vmstat -z' output

[Alexander Best]

hi there,

i'm seeing the following with 'vmstat -z' on CURRENT, running on amd64:

ITEM                   SIZE  LIMIT     USED     FREE      REQ FAIL SLEEP
128 Bucket:            1048,      0,     150,       0,    1650,12746,   0

...how can the number of failures be greater than the number of requests?

cheers.
alex