NODE_MAP_PFN_ALIGNME(9)             Memory Management in Linux            NODE_MAP_PFN_ALIGNME(9)



NAME
       node_map_pfn_alignment - determine the maximum internode alignment

SYNOPSIS
       unsigned long node_map_pfn_alignment(void);

ARGUMENTS
       void
           no arguments

DESCRIPTION
       This function should be called after node map is populated and sorted. It calculates the
       maximum power of two alignment which can distinguish all the nodes.

       For example, if all nodes are 1GiB and aligned to 1GiB, the return value would indicate
       1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the nodes are shifted by 256MiB, 256MiB.
       Note that if only the last node is shifted, 1GiB is enough and this function will indicate
       so.

       This is used to test whether pfn -> nid mapping of the chosen memory model has fine enough
       granularity to avoid incorrect mapping for the populated node map.

       Returns the determined alignment in pfn's. 0 if there is no alignment requirement (single
       node).

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                   NODE_MAP_PFN_ALIGNME(9)