mm/memory_hotplug.c

   1 /*
   2  *  linux/mm/memory_hotplug.c
   3  *
   4  *  Copyright (C)
   5  */
   6
   7 #include <linux/config.h>
   8 #include <linux/stddef.h>
   9 #include <linux/mm.h>
  10 #include <linux/swap.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/pagemap.h>
  13 #include <linux/bootmem.h>
  14 #include <linux/compiler.h>
  15 #include <linux/module.h>
  16 #include <linux/pagevec.h>
  17 #include <linux/slab.h>
  18 #include <linux/sysctl.h>
  19 #include <linux/cpu.h>
  20 #include <linux/memory.h>
  21 #include <linux/memory_hotplug.h>
  22 #include <linux/highmem.h>
  23 #include <linux/vmalloc.h>
  24
  25 #include <asm/tlbflush.h>
  26
  27 static struct page *__kmalloc_section_memmap(unsigned long nr_pages)
  28 {
  29         struct page *page, *ret;
  30         unsigned long memmap_size = sizeof(struct page) * nr_pages;
  31
  32         page = alloc_pages(GFP_KERNEL, get_order(memmap_size));
  33         if (page)
  34                 goto got_map_page;
  35
  36         ret = vmalloc(memmap_size);
  37         if (ret)
  38                 goto got_map_ptr;
  39
  40         return NULL;
  41 got_map_page:
  42         ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
  43 got_map_ptr:
  44         memset(ret, 0, memmap_size);
  45
  46         return ret;
  47 }
  48
  49 extern void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn,
  50                           unsigned long size);
  51 static void __add_zone(struct zone *zone, unsigned long phys_start_pfn)
  52 {
  53         struct pglist_data *pgdat = zone->zone_pgdat;
  54         int nr_pages = PAGES_PER_SECTION;
  55         int nid = pgdat->node_id;
  56         int zone_type;
  57
  58         zone_type = zone - pgdat->node_zones;
  59         memmap_init_zone(nr_pages, nid, zone_type, phys_start_pfn);
  60         zonetable_add(zone, nid, zone_type, phys_start_pfn, nr_pages);
  61 }
  62
  63 extern int sparse_add_one_section(struct zone *, unsigned long,
  64                                   struct page *mem_map);
  65 static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
  66 {
  67         struct pglist_data *pgdat = zone->zone_pgdat;
  68         int nr_pages = PAGES_PER_SECTION;
  69         struct page *memmap;
  70         int ret;
  71
  72         /*
  73          * This can potentially allocate memory, and does its own
  74          * internal locking.
  75          */
  76         sparse_index_init(pfn_to_section_nr(phys_start_pfn), pgdat->node_id);
  77
  78         pgdat_resize_lock(pgdat, &flags);
  79         memmap = __kmalloc_section_memmap(nr_pages);
  80         ret = sparse_add_one_section(zone, phys_start_pfn, memmap);
  81         pgdat_resize_unlock(pgdat, &flags);
  82
  83         if (ret <= 0) {
  84                 /* the mem_map didn't get used */
  85                 if (memmap >= (struct page *)VMALLOC_START &&
  86                     memmap < (struct page *)VMALLOC_END)
  87                         vfree(memmap);
  88                 else
  89                         free_pages((unsigned long)memmap,
  90                                    get_order(sizeof(struct page) * nr_pages));
  91         }
  92
  93         if (ret < 0)
  94                 return ret;
  95
  96         __add_zone(zone, phys_start_pfn);
  97         return register_new_memory(__pfn_to_section(phys_start_pfn));
  98 }
  99
 100 /*
 101  * Reasonably generic function for adding memory.  It is
 102  * expected that archs that support memory hotplug will
 103  * call this function after deciding the zone to which to
 104  * add the new pages.
 105  */
 106 int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
 107                  unsigned long nr_pages)
 108 {
 109         unsigned long i;
 110         int err = 0;
 111
 112         for (i = 0; i < nr_pages; i += PAGES_PER_SECTION) {
 113                 err = __add_section(zone, phys_start_pfn + i);
 114
 115                 if (err)
 116                         break;
 117         }
 118
 119         return err;
 120 }
 121
 122 static void grow_zone_span(struct zone *zone,
 123                 unsigned long start_pfn, unsigned long end_pfn)
 124 {
 125         unsigned long old_zone_end_pfn;
 126
 127         zone_span_writelock(zone);
 128
 129         old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
 130         if (start_pfn < zone->zone_start_pfn)
 131                 zone->zone_start_pfn = start_pfn;
 132
 133         if (end_pfn > old_zone_end_pfn)
 134                 zone->spanned_pages = end_pfn - zone->zone_start_pfn;
 135
 136         zone_span_writeunlock(zone);
 137 }
 138
 139 static void grow_pgdat_span(struct pglist_data *pgdat,
 140                 unsigned long start_pfn, unsigned long end_pfn)
 141 {
 142         unsigned long old_pgdat_end_pfn =
 143                 pgdat->node_start_pfn + pgdat->node_spanned_pages;
 144
 145         if (start_pfn < pgdat->node_start_pfn)
 146                 pgdat->node_start_pfn = start_pfn;
 147
 148         if (end_pfn > old_pgdat_end_pfn)
 149                 pgdat->node_spanned_pages = end_pfn - pgdat->node_spanned_pages;
 150 }
 151
 152 int online_pages(unsigned long pfn, unsigned long nr_pages)
 153 {
 154         unsigned long i;
 155         unsigned long flags;
 156         unsigned long onlined_pages = 0;
 157         struct zone *zone;
 158
 159         /*
 160          * This doesn't need a lock to do pfn_to_page().
 161          * The section can't be removed here because of the
 162          * memory_block->state_sem.
 163          */
 164         zone = page_zone(pfn_to_page(pfn));
 165         pgdat_resize_lock(zone->zone_pgdat, &flags);
 166         grow_zone_span(zone, pfn, pfn + nr_pages);
 167         grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages);
 168         pgdat_resize_unlock(zone->zone_pgdat, &flags);
 169
 170         for (i = 0; i < nr_pages; i++) {
 171                 struct page *page = pfn_to_page(pfn + i);
 172                 online_page(page);
 173                 onlined_pages++;
 174         }
 175         zone->present_pages += onlined_pages;
 176
 177         return 0;
 178 }