Man page 9 : get_pfn_range_for_nid

get_pfn_range_for_nid - Return the start and end page frames for a node

void __meminit get_pfn_range_for_nid(unsigned int  nid , unsigned long *  start_pfn , unsigned long *  end_pfn );

nid
    The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.

start_pfn
    Passed by reference. On return, it will have the node start_pfn.

end_pfn
    Passed by reference. On return, it will have the node end_pfn.

It returns the start and end page frame of a node based on information provided by an arch calling add_active_range. If called for a node with no available memory, a warning is printed and the start and end PFNs will be 0.