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