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/cpu.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mm.h>
  16 #include <linux/node.h>
  17 #include <linux/init.h>
  18 #include <linux/bootmem.h>
  19 #include <asm/mmzone.h>
  20 #include <asm/numa.h>
  21
  22
  23 /*
  24  * The following structures are usually initialized by ACPI or
  25  * similar mechanisms and describe the NUMA characteristics of the machine.
  26  */
  27 int num_node_memblks;
  28 struct node_memblk_s node_memblk[NR_NODE_MEMBLKS];
  29 struct node_cpuid_s node_cpuid[NR_CPUS];
  30 /*
  31  * This is a matrix with "distances" between nodes, they should be
  32  * proportional to the memory access latency ratios.
  33  */
  34 u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES];
  35
  36 /* Identify which cnode a physical address resides on */
  37 int
  38 paddr_to_nid(unsigned long paddr)
  39 {
  40         int     i;
  41
  42         for (i = 0; i < num_node_memblks; i++)
  43                 if (paddr >= node_memblk[i].start_paddr &&
  44                     paddr < node_memblk[i].start_paddr + node_memblk[i].size)
  45                         break;
  46
  47         return (i < num_node_memblks) ? node_memblk[i].nid : (num_node_memblks ? -1 : 0);
  48 }
  49
  50 #if defined(CONFIG_SPARSEMEM) && defined(CONFIG_NUMA)
  51 /*
  52  * Because of holes evaluate on section limits.
  53  * If the section of memory exists, then return the node where the section
  54  * resides.  Otherwise return node 0 as the default.  This is used by
  55  * SPARSEMEM to allocate the SPARSEMEM sectionmap on the NUMA node where
  56  * the section resides.
  57  */
  58 int early_pfn_to_nid(unsigned long pfn)
  59 {
  60         int i, section = pfn >> PFN_SECTION_SHIFT, ssec, esec;
  61
  62         for (i = 0; i < num_node_memblks; i++) {
  63                 ssec = node_memblk[i].start_paddr >> PA_SECTION_SHIFT;
  64                 esec = (node_memblk[i].start_paddr + node_memblk[i].size +
  65                         ((1L << PA_SECTION_SHIFT) - 1)) >> PA_SECTION_SHIFT;
  66                 if (section >= ssec && section < esec)
  67                         return node_memblk[i].nid;
  68         }
  69
  70         return 0;
  71 }
  72 #endif