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  */
  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         { [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  */
  37 u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES];
  38
  39 /* Identify which cnode a physical address resides on */
  40 int
  41 paddr_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  */
  61 int __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
  82 int 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
  90 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
  91 #endif
  92 #endif