1 /* 2 * sparse memory mappings. 3 */ 4 #include <linux/mm.h> 5 #include <linux/mmzone.h> 6 #include <linux/bootmem.h> 7 #include <linux/highmem.h> 8 #include <linux/module.h> 9 #include <linux/spinlock.h> 10 #include <linux/vmalloc.h> 11 #include <asm/dma.h> 12 13 /* 14 * Permanent SPARSEMEM data: 15 * 16 * 1) mem_section - memory sections, mem_map's for valid memory 17 */ 18 #ifdef CONFIG_SPARSEMEM_EXTREME 19 struct mem_section *mem_section[NR_SECTION_ROOTS] 20 ____cacheline_internodealigned_in_smp; 21 #else 22 struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT] 23 ____cacheline_internodealigned_in_smp; 24 #endif 25 EXPORT_SYMBOL(mem_section); 26 27 #ifdef NODE_NOT_IN_PAGE_FLAGS 28 /* 29 * If we did not store the node number in the page then we have to 30 * do a lookup in the section_to_node_table in order to find which 31 * node the page belongs to. 32 */ 33 #if MAX_NUMNODES <= 256 34 static u8 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned; 35 #else 36 static u16 section_to_node_table[NR_MEM_SECTIONS] __cacheline_aligned; 37 #endif 38 39 int page_to_nid(struct page *page) 40 { 41 return section_to_node_table[page_to_section(page)]; 42 } 43 EXPORT_SYMBOL(page_to_nid); 44 45 static void set_section_nid(unsigned long section_nr, int nid) 46 { 47 section_to_node_table[section_nr] = nid; 48 } 49 #else /* !NODE_NOT_IN_PAGE_FLAGS */ 50 static inline void set_section_nid(unsigned long section_nr, int nid) 51 { 52 } 53 #endif 54 55 #ifdef CONFIG_SPARSEMEM_EXTREME 56 static struct mem_section noinline __init_refok *sparse_index_alloc(int nid) 57 { 58 struct mem_section *section = NULL; 59 unsigned long array_size = SECTIONS_PER_ROOT * 60 sizeof(struct mem_section); 61 62 if (slab_is_available()) 63 section = kmalloc_node(array_size, GFP_KERNEL, nid); 64 else 65 section = alloc_bootmem_node(NODE_DATA(nid), array_size); 66 67 if (section) 68 memset(section, 0, array_size); 69 70 return section; 71 } 72 73 static int __meminit sparse_index_init(unsigned long section_nr, int nid) 74 { 75 static DEFINE_SPINLOCK(index_init_lock); 76 unsigned long root = SECTION_NR_TO_ROOT(section_nr); 77 struct mem_section *section; 78 int ret = 0; 79 80 if (mem_section[root]) 81 return -EEXIST; 82 83 section = sparse_index_alloc(nid); 84 /* 85 * This lock keeps two different sections from 86 * reallocating for the same index 87 */ 88 spin_lock(&index_init_lock); 89 90 if (mem_section[root]) { 91 ret = -EEXIST; 92 goto out; 93 } 94 95 mem_section[root] = section; 96 out: 97 spin_unlock(&index_init_lock); 98 return ret; 99 } 100 #else /* !SPARSEMEM_EXTREME */ 101 static inline int sparse_index_init(unsigned long section_nr, int nid) 102 { 103 return 0; 104 } 105 #endif 106 107 /* 108 * Although written for the SPARSEMEM_EXTREME case, this happens 109 * to also work for the flat array case becase 110 * NR_SECTION_ROOTS==NR_MEM_SECTIONS. 111 */ 112 int __section_nr(struct mem_section* ms) 113 { 114 unsigned long root_nr; 115 struct mem_section* root; 116 117 for (root_nr = 0; root_nr < NR_SECTION_ROOTS; root_nr++) { 118 root = __nr_to_section(root_nr * SECTIONS_PER_ROOT); 119 if (!root) 120 continue; 121 122 if ((ms >= root) && (ms < (root + SECTIONS_PER_ROOT))) 123 break; 124 } 125 126 return (root_nr * SECTIONS_PER_ROOT) + (ms - root); 127 } 128 129 /* 130 * During early boot, before section_mem_map is used for an actual 131 * mem_map, we use section_mem_map to store the section's NUMA 132 * node. This keeps us from having to use another data structure. The 133 * node information is cleared just before we store the real mem_map. 134 */ 135 static inline unsigned long sparse_encode_early_nid(int nid) 136 { 137 return (nid << SECTION_NID_SHIFT); 138 } 139 140 static inline int sparse_early_nid(struct mem_section *section) 141 { 142 return (section->section_mem_map >> SECTION_NID_SHIFT); 143 } 144 145 /* Record a memory area against a node. */ 146 void __init memory_present(int nid, unsigned long start, unsigned long end) 147 { 148 unsigned long pfn; 149 150 start &= PAGE_SECTION_MASK; 151 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) { 152 unsigned long section = pfn_to_section_nr(pfn); 153 struct mem_section *ms; 154 155 sparse_index_init(section, nid); 156 set_section_nid(section, nid); 157 158 ms = __nr_to_section(section); 159 if (!ms->section_mem_map) 160 ms->section_mem_map = sparse_encode_early_nid(nid) | 161 SECTION_MARKED_PRESENT; 162 } 163 } 164 165 /* 166 * Only used by the i386 NUMA architecures, but relatively 167 * generic code. 168 */ 169 unsigned long __init node_memmap_size_bytes(int nid, unsigned long start_pfn, 170 unsigned long end_pfn) 171 { 172 unsigned long pfn; 173 unsigned long nr_pages = 0; 174 175 for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 176 if (nid != early_pfn_to_nid(pfn)) 177 continue; 178 179 if (pfn_valid(pfn)) 180 nr_pages += PAGES_PER_SECTION; 181 } 182 183 return nr_pages * sizeof(struct page); 184 } 185 186 /* 187 * Subtle, we encode the real pfn into the mem_map such that 188 * the identity pfn - section_mem_map will return the actual 189 * physical page frame number. 190 */ 191 static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long pnum) 192 { 193 return (unsigned long)(mem_map - (section_nr_to_pfn(pnum))); 194 } 195 196 /* 197 * We need this if we ever free the mem_maps. While not implemented yet, 198 * this function is included for parity with its sibling. 199 */ 200 static __attribute((unused)) 201 struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum) 202 { 203 return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum); 204 } 205 206 static int __meminit sparse_init_one_section(struct mem_section *ms, 207 unsigned long pnum, struct page *mem_map) 208 { 209 if (!valid_section(ms)) 210 return -EINVAL; 211 212 ms->section_mem_map &= ~SECTION_MAP_MASK; 213 ms->section_mem_map |= sparse_encode_mem_map(mem_map, pnum); 214 215 return 1; 216 } 217 218 __attribute__((weak)) __init 219 void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size) 220 { 221 return NULL; 222 } 223 224 static struct page __init *sparse_early_mem_map_alloc(unsigned long pnum) 225 { 226 struct page *map; 227 struct mem_section *ms = __nr_to_section(pnum); 228 int nid = sparse_early_nid(ms); 229 230 map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION); 231 if (map) 232 return map; 233 234 map = alloc_bootmem_high_node(NODE_DATA(nid), 235 sizeof(struct page) * PAGES_PER_SECTION); 236 if (map) 237 return map; 238 239 map = alloc_bootmem_node(NODE_DATA(nid), 240 sizeof(struct page) * PAGES_PER_SECTION); 241 if (map) 242 return map; 243 244 printk(KERN_WARNING "%s: allocation failed\n", __FUNCTION__); 245 ms->section_mem_map = 0; 246 return NULL; 247 } 248 249 /* 250 * Allocate the accumulated non-linear sections, allocate a mem_map 251 * for each and record the physical to section mapping. 252 */ 253 void __init sparse_init(void) 254 { 255 unsigned long pnum; 256 struct page *map; 257 258 for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) { 259 if (!valid_section_nr(pnum)) 260 continue; 261 262 map = sparse_early_mem_map_alloc(pnum); 263 if (!map) 264 continue; 265 sparse_init_one_section(__nr_to_section(pnum), pnum, map); 266 } 267 } 268 269 #ifdef CONFIG_MEMORY_HOTPLUG 270 static struct page *__kmalloc_section_memmap(unsigned long nr_pages) 271 { 272 struct page *page, *ret; 273 unsigned long memmap_size = sizeof(struct page) * nr_pages; 274 275 page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size)); 276 if (page) 277 goto got_map_page; 278 279 ret = vmalloc(memmap_size); 280 if (ret) 281 goto got_map_ptr; 282 283 return NULL; 284 got_map_page: 285 ret = (struct page *)pfn_to_kaddr(page_to_pfn(page)); 286 got_map_ptr: 287 memset(ret, 0, memmap_size); 288 289 return ret; 290 } 291 292 static int vaddr_in_vmalloc_area(void *addr) 293 { 294 if (addr >= (void *)VMALLOC_START && 295 addr < (void *)VMALLOC_END) 296 return 1; 297 return 0; 298 } 299 300 static void __kfree_section_memmap(struct page *memmap, unsigned long nr_pages) 301 { 302 if (vaddr_in_vmalloc_area(memmap)) 303 vfree(memmap); 304 else 305 free_pages((unsigned long)memmap, 306 get_order(sizeof(struct page) * nr_pages)); 307 } 308 309 /* 310 * returns the number of sections whose mem_maps were properly 311 * set. If this is <=0, then that means that the passed-in 312 * map was not consumed and must be freed. 313 */ 314 int sparse_add_one_section(struct zone *zone, unsigned long start_pfn, 315 int nr_pages) 316 { 317 unsigned long section_nr = pfn_to_section_nr(start_pfn); 318 struct pglist_data *pgdat = zone->zone_pgdat; 319 struct mem_section *ms; 320 struct page *memmap; 321 unsigned long flags; 322 int ret; 323 324 /* 325 * no locking for this, because it does its own 326 * plus, it does a kmalloc 327 */ 328 sparse_index_init(section_nr, pgdat->node_id); 329 memmap = __kmalloc_section_memmap(nr_pages); 330 331 pgdat_resize_lock(pgdat, &flags); 332 333 ms = __pfn_to_section(start_pfn); 334 if (ms->section_mem_map & SECTION_MARKED_PRESENT) { 335 ret = -EEXIST; 336 goto out; 337 } 338 ms->section_mem_map |= SECTION_MARKED_PRESENT; 339 340 ret = sparse_init_one_section(ms, section_nr, memmap); 341 342 out: 343 pgdat_resize_unlock(pgdat, &flags); 344 if (ret <= 0) 345 __kfree_section_memmap(memmap, nr_pages); 346 return ret; 347 } 348 #endif 349