LXR linux/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 <linux/module.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 */
  28int num_node_memblks;
  29struct node_memblk_s node_memblk[NR_NODE_MEMBLKS];
  30struct node_cpuid_s node_cpuid[NR_CPUS] =
  31        { [0 ... NR_CPUS-1] = { .phys_id = 0, .nid = NUMA_NO_NODE } };
  32
  33/*
  34 * This is a matrix with "distances" between nodes, they should be
  35 * proportional to the memory access latency ratios.
  36 */
  37u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES];
  38
  39/* Identify which cnode a physical address resides on */
  40int
  41paddr_to_nid(unsigned long paddr)
  42{
  43        int     i;
  44
  45        for (i = 0; i < num_node_memblks; i++)
  46                if (paddr >= node_memblk[i].start_paddr &&
  47                    paddr < node_memblk[i].start_paddr + node_memblk[i].size)
  48                        break;
  49
  50        return (i < num_node_memblks) ? node_memblk[i].nid : (num_node_memblks ? -1 : 0);
  51}
  52
  53#if defined(CONFIG_SPARSEMEM) && defined(CONFIG_NUMA)
  54/*
  55 * Because of holes evaluate on section limits.
  56 * If the section of memory exists, then return the node where the section
  57 * resides.  Otherwise return node 0 as the default.  This is used by
  58 * SPARSEMEM to allocate the SPARSEMEM sectionmap on the NUMA node where
  59 * the section resides.
  60 */
  61int __meminit __early_pfn_to_nid(unsigned long pfn)
  62{
  63        int i, section = pfn >> PFN_SECTION_SHIFT, ssec, esec;
  64
  65        for (i = 0; i < num_node_memblks; i++) {
  66                ssec = node_memblk[i].start_paddr >> PA_SECTION_SHIFT;
  67                esec = (node_memblk[i].start_paddr + node_memblk[i].size +
  68                        ((1L << PA_SECTION_SHIFT) - 1)) >> PA_SECTION_SHIFT;
  69                if (section >= ssec && section < esec)
  70                        return node_memblk[i].nid;
  71        }
  72
  73        return -1;
  74}
  75
  76#ifdef CONFIG_MEMORY_HOTPLUG
  77/*
  78 *  SRAT information is stored in node_memblk[], then we can use SRAT
  79 *  information at memory-hot-add if necessary.
  80 */
  81
  82int memory_add_physaddr_to_nid(u64 addr)
  83{
  84        int nid = paddr_to_nid(addr);
  85        if (nid < 0)
  86                return 0;
  87        return nid;
  88}
  89
  90EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
  91#endif
  92#endif
  93