,s!Lock;!Lock lk;!
,s!lock(&ialloc)!lock(\&ialloc.lk)!g
,s!msize(b)!sizeof(Block)+size+Hdrspc!
,s/exit(0)/panic("iallocb")/
/_xinc/d
/_xdec/s/ ||.*0//
,s/ref < 0/0/