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