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 /*
  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 }
  50
  51 #if defined(CONFIG_SPARSEMEM) && defined(CONFIG_NUMA)
  52 /*
  53  * Because of holes evaluate on section limits.
  54  * If the section of memory exists, then return the node where the section
  55  * resides.  Otherwise return node 0 as the default.  This is used by
  56  * SPARSEMEM to allocate the SPARSEMEM sectionmap on the NUMA node where
  57  * the section resides.
  58  */
  59 int early_pfn_to_nid(unsigned long pfn)
  60 {
  61         int i, section = pfn >> PFN_SECTION_SHIFT, ssec, esec;
  62
  63         for (i = 0; i < num_node_memblks; i++) {
  64                 ssec = node_memblk[i].start_paddr >> PA_SECTION_SHIFT;
  65                 esec = (node_memblk[i].start_paddr + node_memblk[i].size +
  66                         ((1L << PA_SECTION_SHIFT) - 1)) >> PA_SECTION_SHIFT;
  67                 if (section >= ssec && section < esec)
  68                         return node_memblk[i].nid;
  69         }
  70
  71         return 0;
  72 }
  73
  74 #ifdef CONFIG_MEMORY_HOTPLUG
  75 /*
  76  *  SRAT information is stored in node_memblk[], then we can use SRAT
  77  *  information at memory-hot-add if necessary.
  78  */
  79
  80 int memory_add_physaddr_to_nid(u64 addr)
  81 {
  82         int nid = paddr_to_nid(addr);
  83         if (nid < 0)
  84                 return 0;
  85         return nid;
  86 }
  87
  88 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
  89 #endif
  90 #endif