NODE_MAP_PFN_ALIGNME(9) Memory Management in Linux NODE_MAP_PFN_ALIGNME(9)NAMEnode_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).
COPYRIGHTKernel Hackers Manual 3.11 November 2013 NODE_MAP_PFN_ALIGNME(9)