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/memblock.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 int __node_distance(int from, int to)
  40 {
  41         return slit_distance(from, to);
  42 }
  43 EXPORT_SYMBOL(__node_distance);
  44
  45 /* Identify which cnode a physical address resides on */
  46 int
  47 paddr_to_nid(unsigned long paddr)
  48 {
  49         int     i;
  50
  51         for (i = 0; i < num_node_memblks; i++)
  52                 if (paddr >= node_memblk[i].start_paddr &&
  53                     paddr < node_memblk[i].start_paddr + node_memblk[i].size)
  54                         break;
  55
  56         return (i < num_node_memblks) ? node_memblk[i].nid : (num_node_memblks ? -1 : 0);
  57 }
  58 EXPORT_SYMBOL(paddr_to_nid);
  59
  60 #if defined(CONFIG_SPARSEMEM) && defined(CONFIG_NUMA)
  61 /*
  62  * Because of holes evaluate on section limits.
  63  * If the section of memory exists, then return the node where the section
  64  * resides.  Otherwise return node 0 as the default.  This is used by
  65  * SPARSEMEM to allocate the SPARSEMEM sectionmap on the NUMA node where
  66  * the section resides.
  67  */
  68 int __meminit __early_pfn_to_nid(unsigned long pfn,
  69                                         struct mminit_pfnnid_cache *state)
  70 {
  71         int i, section = pfn >> PFN_SECTION_SHIFT, ssec, esec;
  72
  73         if (section >= state->last_start && section < state->last_end)
  74                 return state->last_nid;
  75
  76         for (i = 0; i < num_node_memblks; i++) {
  77                 ssec = node_memblk[i].start_paddr >> PA_SECTION_SHIFT;
  78                 esec = (node_memblk[i].start_paddr + node_memblk[i].size +
  79                         ((1L << PA_SECTION_SHIFT) - 1)) >> PA_SECTION_SHIFT;
  80                 if (section >= ssec && section < esec) {
  81                         state->last_start = ssec;
  82                         state->last_end = esec;
  83                         state->last_nid = node_memblk[i].nid;
  84                         return node_memblk[i].nid;
  85                 }
  86         }
  87
  88         return -1;
  89 }
  90
  91 void numa_clear_node(int cpu)
  92 {
  93         unmap_cpu_from_node(cpu, NUMA_NO_NODE);
  94 }
  95
  96 #ifdef CONFIG_MEMORY_HOTPLUG
  97 /*
  98  *  SRAT information is stored in node_memblk[], then we can use SRAT
  99  *  information at memory-hot-add if necessary.
 100  */
 101
 102 int memory_add_physaddr_to_nid(u64 addr)
 103 {
 104         int nid = paddr_to_nid(addr);
 105         if (nid < 0)
 106                 return 0;
 107         return nid;
 108 }
 109
 110 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 111 #endif
 112 #endif