numa.c
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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* This file contains NUMA specific variables and functions which can
* be split away from DISCONTIGMEM and are used on NUMA machines with
* contiguous memory.
*
* 2002/08/07 Erich Focht <efocht@ess.nec.de>
*/
#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/node.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/module.h>
#include <asm/mmzone.h>
#include <asm/numa.h>
/*
* The following structures are usually initialized by ACPI or
* similar mechanisms and describe the NUMA characteristics of the machine.
*/
int num_node_memblks;
struct node_memblk_s node_memblk[NR_NODE_MEMBLKS];
struct node_cpuid_s node_cpuid[NR_CPUS] =
{ [0 ... NR_CPUS-1] = { .phys_id = 0, .nid = NUMA_NO_NODE } };
/*
* This is a matrix with "distances" between nodes, they should be
* proportional to the memory access latency ratios.
*/
u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES];
/* Identify which cnode a physical address resides on */
int
paddr_to_nid(unsigned long paddr)
{
int i;
for (i = 0; i < num_node_memblks; i++)
if (paddr >= node_memblk[i].start_paddr &&
paddr < node_memblk[i].start_paddr + node_memblk[i].size)
break;
return (i < num_node_memblks) ? node_memblk[i].nid : (num_node_memblks ? -1 : 0);
}
#if defined(CONFIG_SPARSEMEM) && defined(CONFIG_NUMA)
/*
* Because of holes evaluate on section limits.
* If the section of memory exists, then return the node where the section
* resides. Otherwise return node 0 as the default. This is used by
* SPARSEMEM to allocate the SPARSEMEM sectionmap on the NUMA node where
* the section resides.
*/
int __meminit __early_pfn_to_nid(unsigned long pfn)
{
int i, section = pfn >> PFN_SECTION_SHIFT, ssec, esec;
/*
* NOTE: The following SMP-unsafe globals are only used early in boot
* when the kernel is running single-threaded.
*/
static int __meminitdata last_ssec, last_esec;
static int __meminitdata last_nid;
if (section >= last_ssec && section < last_esec)
return last_nid;
for (i = 0; i < num_node_memblks; i++) {
ssec = node_memblk[i].start_paddr >> PA_SECTION_SHIFT;
esec = (node_memblk[i].start_paddr + node_memblk[i].size +
((1L << PA_SECTION_SHIFT) - 1)) >> PA_SECTION_SHIFT;
if (section >= ssec && section < esec) {
last_ssec = ssec;
last_esec = esec;
last_nid = node_memblk[i].nid;
return node_memblk[i].nid;
}
}
return -1;
}
void numa_clear_node(int cpu)
{
unmap_cpu_from_node(cpu, NUMA_NO_NODE);
}
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* SRAT information is stored in node_memblk[], then we can use SRAT
* information at memory-hot-add if necessary.
*/
int memory_add_physaddr_to_nid(u64 addr)
{
int nid = paddr_to_nid(addr);
if (nid < 0)
return 0;
return nid;
}
EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
#endif
#endif