'\" t
.\"     Title: node_map_pfn_alignment
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: June 2017
.\"    Manual: Memory Management in Linux
.\"    Source: Kernel Hackers Manual 4.11.3
.\"  Language: English
.\"
.TH "NODE_MAP_PFN_ALIGNME" "9" "June 2017" "Kernel Hackers Manual 4\&.11\&" "Memory Management in Linux"
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.SH "NAME"
node_map_pfn_alignment \- determine the maximum internode alignment
.SH "SYNOPSIS"
.HP \w'unsigned\ long\ node_map_pfn_alignment('u
.BI "unsigned long node_map_pfn_alignment(" "void" ");"
.SH "ARGUMENTS"
.PP
\fI void\fR
.RS 4
no arguments
.RE
.SH "DESCRIPTION"
.PP
.PP
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\&.
.PP
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\&.
.PP
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\&.
.PP
Returns the determined alignment in pfn\*(Aqs\&. 0 if there is no alignment requirement (single node)\&.
.SH "COPYRIGHT"
.br