arch/ia64/mm/numa.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * This file contains NUMA specific variables and functions which can
   7  * be split away from DISCONTIGMEM and are used on NUMA machines with
   8  * contiguous memory.
   9  *
  10  *                         2002/08/07 Erich Focht <efocht@ess.nec.de>
  11  */
  12
  13 #include <linux/config.h>
  14 #include <linux/cpu.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mm.h>
  17 #include <linux/node.h>
  18 #include <linux/init.h>
  19 #include <linux/bootmem.h>
  20 #include <asm/mmzone.h>
  21 #include <asm/numa.h>
  22
  23
  24 /*
  25  * The following structures are usually initialized by ACPI or
  26  * similar mechanisms and describe the NUMA characteristics of the machine.
  27  */
  28 int num_node_memblks;
  29 struct node_memblk_s node_memblk[NR_NODE_MEMBLKS];
  30 struct node_cpuid_s node_cpuid[NR_CPUS];
  31 /*
  32  * This is a matrix with "distances" between nodes, they should be
  33  * proportional to the memory access latency ratios.
  34  */
  35 u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES];
  36
  37 /* Identify which cnode a physical address resides on */
  38 int
  39 paddr_to_nid(unsigned long paddr)
  40 {
  41         int     i;
  42
  43         for (i = 0; i < num_node_memblks; i++)
  44                 if (paddr >= node_memblk[i].start_paddr &&
  45                     paddr < node_memblk[i].start_paddr + node_memblk[i].size)
  46                         break;
  47
  48         return (i < num_node_memblks) ? node_memblk[i].nid : (num_node_memblks ? -1 : 0);
  49 }