mm/memory_hotplug.c

   1 /*
   2  *  linux/mm/memory_hotplug.c
   3  *
   4  *  Copyright (C)
   5  */
   6
   7 #include <linux/stddef.h>
   8 #include <linux/mm.h>
   9 #include <linux/swap.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/pagemap.h>
  12 #include <linux/bootmem.h>
  13 #include <linux/compiler.h>
  14 #include <linux/module.h>
  15 #include <linux/pagevec.h>
  16 #include <linux/writeback.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 #include <linux/ioport.h>
  25 #include <linux/cpuset.h>
  26
  27 #include <asm/tlbflush.h>
  28
  29 /* add this memory to iomem resource */
  30 static struct resource *register_memory_resource(u64 start, u64 size)
  31 {
  32         struct resource *res;
  33         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
  34         BUG_ON(!res);
  35
  36         res->name = "System RAM";
  37         res->start = start;
  38         res->end = start + size - 1;
  39         res->flags = IORESOURCE_MEM;
  40         if (request_resource(&iomem_resource, res) < 0) {
  41                 printk("System RAM resource %llx - %llx cannot be added\n",
  42                 (unsigned long long)res->start, (unsigned long long)res->end);
  43                 kfree(res);
  44                 res = NULL;
  45         }
  46         return res;
  47 }
  48
  49 static void release_memory_resource(struct resource *res)
  50 {
  51         if (!res)
  52                 return;
  53         release_resource(res);
  54         kfree(res);
  55         return;
  56 }
  57
  58
  59 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
  60 static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
  61 {
  62         struct pglist_data *pgdat = zone->zone_pgdat;
  63         int nr_pages = PAGES_PER_SECTION;
  64         int nid = pgdat->node_id;
  65         int zone_type;
  66
  67         zone_type = zone - pgdat->node_zones;
  68         if (!populated_zone(zone)) {
  69                 int ret = 0;
  70                 ret = init_currently_empty_zone(zone, phys_start_pfn,
  71                                                 nr_pages, MEMMAP_HOTPLUG);
  72                 if (ret < 0)
  73                         return ret;
  74         }
  75         memmap_init_zone(nr_pages, nid, zone_type,
  76                          phys_start_pfn, MEMMAP_HOTPLUG);
  77         return 0;
  78 }
  79
  80 static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
  81 {
  82         int nr_pages = PAGES_PER_SECTION;
  83         int ret;
  84
  85         if (pfn_valid(phys_start_pfn))
  86                 return -EEXIST;
  87
  88         ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
  89
  90         if (ret < 0)
  91                 return ret;
  92
  93         ret = __add_zone(zone, phys_start_pfn);
  94
  95         if (ret < 0)
  96                 return ret;
  97
  98         return register_new_memory(__pfn_to_section(phys_start_pfn));
  99 }
 100
 101 /*
 102  * Reasonably generic function for adding memory.  It is
 103  * expected that archs that support memory hotplug will
 104  * call this function after deciding the zone to which to
 105  * add the new pages.
 106  */
 107 int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
 108                  unsigned long nr_pages)
 109 {
 110         unsigned long i;
 111         int err = 0;
 112         int start_sec, end_sec;
 113         /* during initialize mem_map, align hot-added range to section */
 114         start_sec = pfn_to_section_nr(phys_start_pfn);
 115         end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
 116
 117         for (i = start_sec; i <= end_sec; i++) {
 118                 err = __add_section(zone, i << PFN_SECTION_SHIFT);
 119
 120                 /*
 121                  * EEXIST is finally dealed with by ioresource collision
 122                  * check. see add_memory() => register_memory_resource()
 123                  * Warning will be printed if there is collision.
 124                  */
 125                 if (err && (err != -EEXIST))
 126                         break;
 127                 err = 0;
 128         }
 129
 130         return err;
 131 }
 132 EXPORT_SYMBOL_GPL(__add_pages);
 133
 134 static void grow_zone_span(struct zone *zone,
 135                 unsigned long start_pfn, unsigned long end_pfn)
 136 {
 137         unsigned long old_zone_end_pfn;
 138
 139         zone_span_writelock(zone);
 140
 141         old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
 142         if (start_pfn < zone->zone_start_pfn)
 143                 zone->zone_start_pfn = start_pfn;
 144
 145         zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
 146                                 zone->zone_start_pfn;
 147
 148         zone_span_writeunlock(zone);
 149 }
 150
 151 static void grow_pgdat_span(struct pglist_data *pgdat,
 152                 unsigned long start_pfn, unsigned long end_pfn)
 153 {
 154         unsigned long old_pgdat_end_pfn =
 155                 pgdat->node_start_pfn + pgdat->node_spanned_pages;
 156
 157         if (start_pfn < pgdat->node_start_pfn)
 158                 pgdat->node_start_pfn = start_pfn;
 159
 160         pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
 161                                         pgdat->node_start_pfn;
 162 }
 163
 164 int online_pages(unsigned long pfn, unsigned long nr_pages)
 165 {
 166         unsigned long i;
 167         unsigned long flags;
 168         unsigned long onlined_pages = 0;
 169         struct resource res;
 170         u64 section_end;
 171         unsigned long start_pfn;
 172         struct zone *zone;
 173         int need_zonelists_rebuild = 0;
 174
 175         /*
 176          * This doesn't need a lock to do pfn_to_page().
 177          * The section can't be removed here because of the
 178          * memory_block->state_sem.
 179          */
 180         zone = page_zone(pfn_to_page(pfn));
 181         pgdat_resize_lock(zone->zone_pgdat, &flags);
 182         grow_zone_span(zone, pfn, pfn + nr_pages);
 183         grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages);
 184         pgdat_resize_unlock(zone->zone_pgdat, &flags);
 185
 186         /*
 187          * If this zone is not populated, then it is not in zonelist.
 188          * This means the page allocator ignores this zone.
 189          * So, zonelist must be updated after online.
 190          */
 191         if (!populated_zone(zone))
 192                 need_zonelists_rebuild = 1;
 193
 194         res.start = (u64)pfn << PAGE_SHIFT;
 195         res.end = res.start + ((u64)nr_pages << PAGE_SHIFT) - 1;
 196         res.flags = IORESOURCE_MEM; /* we just need system ram */
 197         section_end = res.end;
 198
 199         while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
 200                 start_pfn = (unsigned long)(res.start >> PAGE_SHIFT);
 201                 nr_pages = (unsigned long)
 202                            ((res.end + 1 - res.start) >> PAGE_SHIFT);
 203
 204                 if (PageReserved(pfn_to_page(start_pfn))) {
 205                         /* this region's page is not onlined now */
 206                         for (i = 0; i < nr_pages; i++) {
 207                                 struct page *page = pfn_to_page(start_pfn + i);
 208                                 online_page(page);
 209                                 onlined_pages++;
 210                         }
 211                 }
 212
 213                 res.start = res.end + 1;
 214                 res.end = section_end;
 215         }
 216         zone->present_pages += onlined_pages;
 217         zone->zone_pgdat->node_present_pages += onlined_pages;
 218
 219         setup_per_zone_pages_min();
 220
 221         if (need_zonelists_rebuild)
 222                 build_all_zonelists();
 223         vm_total_pages = nr_free_pagecache_pages();
 224         writeback_set_ratelimit();
 225         return 0;
 226 }
 227 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
 228
 229 static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
 230 {
 231         struct pglist_data *pgdat;
 232         unsigned long zones_size[MAX_NR_ZONES] = {0};
 233         unsigned long zholes_size[MAX_NR_ZONES] = {0};
 234         unsigned long start_pfn = start >> PAGE_SHIFT;
 235
 236         pgdat = arch_alloc_nodedata(nid);
 237         if (!pgdat)
 238                 return NULL;
 239
 240         arch_refresh_nodedata(nid, pgdat);
 241
 242         /* we can use NODE_DATA(nid) from here */
 243
 244         /* init node's zones as empty zones, we don't have any present pages.*/
 245         free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
 246
 247         return pgdat;
 248 }
 249
 250 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
 251 {
 252         arch_refresh_nodedata(nid, NULL);
 253         arch_free_nodedata(pgdat);
 254         return;
 255 }
 256
 257
 258 int add_memory(int nid, u64 start, u64 size)
 259 {
 260         pg_data_t *pgdat = NULL;
 261         int new_pgdat = 0;
 262         struct resource *res;
 263         int ret;
 264
 265         res = register_memory_resource(start, size);
 266         if (!res)
 267                 return -EEXIST;
 268
 269         if (!node_online(nid)) {
 270                 pgdat = hotadd_new_pgdat(nid, start);
 271                 if (!pgdat)
 272                         return -ENOMEM;
 273                 new_pgdat = 1;
 274                 ret = kswapd_run(nid);
 275                 if (ret)
 276                         goto error;
 277         }
 278
 279         /* call arch's memory hotadd */
 280         ret = arch_add_memory(nid, start, size);
 281
 282         if (ret < 0)
 283                 goto error;
 284
 285         /* we online node here. we can't roll back from here. */
 286         node_set_online(nid);
 287
 288         cpuset_track_online_nodes();
 289
 290         if (new_pgdat) {
 291                 ret = register_one_node(nid);
 292                 /*
 293                  * If sysfs file of new node can't create, cpu on the node
 294                  * can't be hot-added. There is no rollback way now.
 295                  * So, check by BUG_ON() to catch it reluctantly..
 296                  */
 297                 BUG_ON(ret);
 298         }
 299
 300         return ret;
 301 error:
 302         /* rollback pgdat allocation and others */
 303         if (new_pgdat)
 304                 rollback_node_hotadd(nid, pgdat);
 305         if (res)
 306                 release_memory_resource(res);
 307
 308         return ret;
 309 }
 310 EXPORT_SYMBOL_GPL(add_memory);