linux26-avoid-memory-zone-fun-20050113

linux26-avoid-memory-zone-fun-20050113

FIXES 16965

"  the wake_up_bit() mechanism has replaced
'per object' wait queues (atleast when testing for single bit changes).
the actual wait queue to use is determined using a hash on page->flags
(which encodes the zone table in the lower 8 bits).  afs inodes come from
a vmalloc() since afs gets all the inodes in one go.  vmalloc()'d memory
apparently doesnt get mapped to any particular zone.  so when an afs
inode uses wake_up_bit() they index off the end of the zone_page table.
"