memory_hotplug.c revision 38837fc75acb7fa9b0e111b0241fe4fe76c5d4b3
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/slab.h> 17#include <linux/sysctl.h> 18#include <linux/cpu.h> 19#include <linux/memory.h> 20#include <linux/memory_hotplug.h> 21#include <linux/highmem.h> 22#include <linux/vmalloc.h> 23#include <linux/ioport.h> 24#include <linux/cpuset.h> 25 26#include <asm/tlbflush.h> 27 28extern void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn, 29 unsigned long size); 30static int __add_zone(struct zone *zone, unsigned long phys_start_pfn) 31{ 32 struct pglist_data *pgdat = zone->zone_pgdat; 33 int nr_pages = PAGES_PER_SECTION; 34 int nid = pgdat->node_id; 35 int zone_type; 36 37 zone_type = zone - pgdat->node_zones; 38 if (!populated_zone(zone)) { 39 int ret = 0; 40 ret = init_currently_empty_zone(zone, phys_start_pfn, nr_pages); 41 if (ret < 0) 42 return ret; 43 } 44 memmap_init_zone(nr_pages, nid, zone_type, phys_start_pfn); 45 zonetable_add(zone, nid, zone_type, phys_start_pfn, nr_pages); 46 return 0; 47} 48 49extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn, 50 int nr_pages); 51static int __add_section(struct zone *zone, unsigned long phys_start_pfn) 52{ 53 int nr_pages = PAGES_PER_SECTION; 54 int ret; 55 56 if (pfn_valid(phys_start_pfn)) 57 return -EEXIST; 58 59 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); 60 61 if (ret < 0) 62 return ret; 63 64 ret = __add_zone(zone, phys_start_pfn); 65 66 if (ret < 0) 67 return ret; 68 69 return register_new_memory(__pfn_to_section(phys_start_pfn)); 70} 71 72/* 73 * Reasonably generic function for adding memory. It is 74 * expected that archs that support memory hotplug will 75 * call this function after deciding the zone to which to 76 * add the new pages. 77 */ 78int __add_pages(struct zone *zone, unsigned long phys_start_pfn, 79 unsigned long nr_pages) 80{ 81 unsigned long i; 82 int err = 0; 83 int start_sec, end_sec; 84 /* during initialize mem_map, align hot-added range to section */ 85 start_sec = pfn_to_section_nr(phys_start_pfn); 86 end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); 87 88 for (i = start_sec; i <= end_sec; i++) { 89 err = __add_section(zone, i << PFN_SECTION_SHIFT); 90 91 /* 92 * EEXIST is finally dealed with by ioresource collision 93 * check. see add_memory() => register_memory_resource() 94 * Warning will be printed if there is collision. 95 */ 96 if (err && (err != -EEXIST)) 97 break; 98 err = 0; 99 } 100 101 return err; 102} 103EXPORT_SYMBOL_GPL(__add_pages); 104 105static void grow_zone_span(struct zone *zone, 106 unsigned long start_pfn, unsigned long end_pfn) 107{ 108 unsigned long old_zone_end_pfn; 109 110 zone_span_writelock(zone); 111 112 old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; 113 if (start_pfn < zone->zone_start_pfn) 114 zone->zone_start_pfn = start_pfn; 115 116 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - 117 zone->zone_start_pfn; 118 119 zone_span_writeunlock(zone); 120} 121 122static void grow_pgdat_span(struct pglist_data *pgdat, 123 unsigned long start_pfn, unsigned long end_pfn) 124{ 125 unsigned long old_pgdat_end_pfn = 126 pgdat->node_start_pfn + pgdat->node_spanned_pages; 127 128 if (start_pfn < pgdat->node_start_pfn) 129 pgdat->node_start_pfn = start_pfn; 130 131 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - 132 pgdat->node_start_pfn; 133} 134 135int online_pages(unsigned long pfn, unsigned long nr_pages) 136{ 137 unsigned long i; 138 unsigned long flags; 139 unsigned long onlined_pages = 0; 140 struct resource res; 141 u64 section_end; 142 unsigned long start_pfn; 143 struct zone *zone; 144 int need_zonelists_rebuild = 0; 145 146 /* 147 * This doesn't need a lock to do pfn_to_page(). 148 * The section can't be removed here because of the 149 * memory_block->state_sem. 150 */ 151 zone = page_zone(pfn_to_page(pfn)); 152 pgdat_resize_lock(zone->zone_pgdat, &flags); 153 grow_zone_span(zone, pfn, pfn + nr_pages); 154 grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages); 155 pgdat_resize_unlock(zone->zone_pgdat, &flags); 156 157 /* 158 * If this zone is not populated, then it is not in zonelist. 159 * This means the page allocator ignores this zone. 160 * So, zonelist must be updated after online. 161 */ 162 if (!populated_zone(zone)) 163 need_zonelists_rebuild = 1; 164 165 res.start = (u64)pfn << PAGE_SHIFT; 166 res.end = res.start + ((u64)nr_pages << PAGE_SHIFT) - 1; 167 res.flags = IORESOURCE_MEM; /* we just need system ram */ 168 section_end = res.end; 169 170 while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) { 171 start_pfn = (unsigned long)(res.start >> PAGE_SHIFT); 172 nr_pages = (unsigned long) 173 ((res.end + 1 - res.start) >> PAGE_SHIFT); 174 175 if (PageReserved(pfn_to_page(start_pfn))) { 176 /* this region's page is not onlined now */ 177 for (i = 0; i < nr_pages; i++) { 178 struct page *page = pfn_to_page(start_pfn + i); 179 online_page(page); 180 onlined_pages++; 181 } 182 } 183 184 res.start = res.end + 1; 185 res.end = section_end; 186 } 187 zone->present_pages += onlined_pages; 188 zone->zone_pgdat->node_present_pages += onlined_pages; 189 190 setup_per_zone_pages_min(); 191 192 if (need_zonelists_rebuild) 193 build_all_zonelists(); 194 vm_total_pages = nr_free_pagecache_pages(); 195 return 0; 196} 197 198static pg_data_t *hotadd_new_pgdat(int nid, u64 start) 199{ 200 struct pglist_data *pgdat; 201 unsigned long zones_size[MAX_NR_ZONES] = {0}; 202 unsigned long zholes_size[MAX_NR_ZONES] = {0}; 203 unsigned long start_pfn = start >> PAGE_SHIFT; 204 205 pgdat = arch_alloc_nodedata(nid); 206 if (!pgdat) 207 return NULL; 208 209 arch_refresh_nodedata(nid, pgdat); 210 211 /* we can use NODE_DATA(nid) from here */ 212 213 /* init node's zones as empty zones, we don't have any present pages.*/ 214 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size); 215 216 return pgdat; 217} 218 219static void rollback_node_hotadd(int nid, pg_data_t *pgdat) 220{ 221 arch_refresh_nodedata(nid, NULL); 222 arch_free_nodedata(pgdat); 223 return; 224} 225 226/* add this memory to iomem resource */ 227static struct resource *register_memory_resource(u64 start, u64 size) 228{ 229 struct resource *res; 230 res = kzalloc(sizeof(struct resource), GFP_KERNEL); 231 BUG_ON(!res); 232 233 res->name = "System RAM"; 234 res->start = start; 235 res->end = start + size - 1; 236 res->flags = IORESOURCE_MEM; 237 if (request_resource(&iomem_resource, res) < 0) { 238 printk("System RAM resource %llx - %llx cannot be added\n", 239 (unsigned long long)res->start, (unsigned long long)res->end); 240 kfree(res); 241 res = NULL; 242 } 243 return res; 244} 245 246static void release_memory_resource(struct resource *res) 247{ 248 if (!res) 249 return; 250 release_resource(res); 251 kfree(res); 252 return; 253} 254 255 256 257int add_memory(int nid, u64 start, u64 size) 258{ 259 pg_data_t *pgdat = NULL; 260 int new_pgdat = 0; 261 struct resource *res; 262 int ret; 263 264 res = register_memory_resource(start, size); 265 if (!res) 266 return -EEXIST; 267 268 if (!node_online(nid)) { 269 pgdat = hotadd_new_pgdat(nid, start); 270 if (!pgdat) 271 return -ENOMEM; 272 new_pgdat = 1; 273 ret = kswapd_run(nid); 274 if (ret) 275 goto error; 276 } 277 278 /* call arch's memory hotadd */ 279 ret = arch_add_memory(nid, start, size); 280 281 if (ret < 0) 282 goto error; 283 284 /* we online node here. we can't roll back from here. */ 285 node_set_online(nid); 286 287 cpuset_track_online_nodes(); 288 289 if (new_pgdat) { 290 ret = register_one_node(nid); 291 /* 292 * If sysfs file of new node can't create, cpu on the node 293 * can't be hot-added. There is no rollback way now. 294 * So, check by BUG_ON() to catch it reluctantly.. 295 */ 296 BUG_ON(ret); 297 } 298 299 return ret; 300error: 301 /* rollback pgdat allocation and others */ 302 if (new_pgdat) 303 rollback_node_hotadd(nid, pgdat); 304 if (res) 305 release_memory_resource(res); 306 307 return ret; 308} 309EXPORT_SYMBOL_GPL(add_memory); 310