On OSR506 platform with 4G memory, the mtune shows:NBUF
0 24 450000,that means the maximum value of NBUF is
450000,but if I give 1000000 to NBUF,when system starts,it give the
following message:

kernel: Hz = 100, i/o bufs = 467116k (high bufs = 466092k)CONFIG:
Buffer allocation was reduced (NBUF reduced to 467116)

(1)That means NBUF gets a value of 467116, where does this number come
from?

ps:
(2) If NBUF has a value other than zero, Is it ok to let NHBUF=0? Can
NHBUF self-tune according to NBUF when NBUF is not set to zero?
(3)When does MAXBUF have effect, when NBUF is zero or NBUF is not zero?