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1// SPDX-License-Identifier: GPL-2.0
2#include <linux/mm.h>
3#include <linux/mmzone.h>
4#include <linux/bootmem.h>
5#include <linux/page_ext.h>
6#include <linux/memory.h>
7#include <linux/vmalloc.h>
8#include <linux/kmemleak.h>
9#include <linux/page_owner.h>
10#include <linux/page_idle.h>
11
12/*
13 * struct page extension
14 *
15 * This is the feature to manage memory for extended data per page.
16 *
17 * Until now, we must modify struct page itself to store extra data per page.
18 * This requires rebuilding the kernel and it is really time consuming process.
19 * And, sometimes, rebuild is impossible due to third party module dependency.
20 * At last, enlarging struct page could cause un-wanted system behaviour change.
21 *
22 * This feature is intended to overcome above mentioned problems. This feature
23 * allocates memory for extended data per page in certain place rather than
24 * the struct page itself. This memory can be accessed by the accessor
25 * functions provided by this code. During the boot process, it checks whether
26 * allocation of huge chunk of memory is needed or not. If not, it avoids
27 * allocating memory at all. With this advantage, we can include this feature
28 * into the kernel in default and can avoid rebuild and solve related problems.
29 *
30 * To help these things to work well, there are two callbacks for clients. One
31 * is the need callback which is mandatory if user wants to avoid useless
32 * memory allocation at boot-time. The other is optional, init callback, which
33 * is used to do proper initialization after memory is allocated.
34 *
35 * The need callback is used to decide whether extended memory allocation is
36 * needed or not. Sometimes users want to deactivate some features in this
37 * boot and extra memory would be unneccessary. In this case, to avoid
38 * allocating huge chunk of memory, each clients represent their need of
39 * extra memory through the need callback. If one of the need callbacks
40 * returns true, it means that someone needs extra memory so that
41 * page extension core should allocates memory for page extension. If
42 * none of need callbacks return true, memory isn't needed at all in this boot
43 * and page extension core can skip to allocate memory. As result,
44 * none of memory is wasted.
45 *
46 * When need callback returns true, page_ext checks if there is a request for
47 * extra memory through size in struct page_ext_operations. If it is non-zero,
48 * extra space is allocated for each page_ext entry and offset is returned to
49 * user through offset in struct page_ext_operations.
50 *
51 * The init callback is used to do proper initialization after page extension
52 * is completely initialized. In sparse memory system, extra memory is
53 * allocated some time later than memmap is allocated. In other words, lifetime
54 * of memory for page extension isn't same with memmap for struct page.
55 * Therefore, clients can't store extra data until page extension is
56 * initialized, even if pages are allocated and used freely. This could
57 * cause inadequate state of extra data per page, so, to prevent it, client
58 * can utilize this callback to initialize the state of it correctly.
59 */
60
61static struct page_ext_operations *page_ext_ops[] = {
62#ifdef CONFIG_DEBUG_PAGEALLOC
63 &debug_guardpage_ops,
64#endif
65#ifdef CONFIG_PAGE_OWNER
66 &page_owner_ops,
67#endif
68#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
69 &page_idle_ops,
70#endif
71};
72
73static unsigned long total_usage;
74static unsigned long extra_mem;
75
76static bool __init invoke_need_callbacks(void)
77{
78 int i;
79 int entries = ARRAY_SIZE(page_ext_ops);
80 bool need = false;
81
82 for (i = 0; i < entries; i++) {
83 if (page_ext_ops[i]->need && page_ext_ops[i]->need()) {
84 page_ext_ops[i]->offset = sizeof(struct page_ext) +
85 extra_mem;
86 extra_mem += page_ext_ops[i]->size;
87 need = true;
88 }
89 }
90
91 return need;
92}
93
94static void __init invoke_init_callbacks(void)
95{
96 int i;
97 int entries = ARRAY_SIZE(page_ext_ops);
98
99 for (i = 0; i < entries; i++) {
100 if (page_ext_ops[i]->init)
101 page_ext_ops[i]->init();
102 }
103}
104
105static unsigned long get_entry_size(void)
106{
107 return sizeof(struct page_ext) + extra_mem;
108}
109
110static inline struct page_ext *get_entry(void *base, unsigned long index)
111{
112 return base + get_entry_size() * index;
113}
114
115#if !defined(CONFIG_SPARSEMEM)
116
117
118void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
119{
120 pgdat->node_page_ext = NULL;
121}
122
123struct page_ext *lookup_page_ext(struct page *page)
124{
125 unsigned long pfn = page_to_pfn(page);
126 unsigned long index;
127 struct page_ext *base;
128
129 base = NODE_DATA(page_to_nid(page))->node_page_ext;
130 /*
131 * The sanity checks the page allocator does upon freeing a
132 * page can reach here before the page_ext arrays are
133 * allocated when feeding a range of pages to the allocator
134 * for the first time during bootup or memory hotplug.
135 */
136 if (unlikely(!base))
137 return NULL;
138 index = pfn - round_down(node_start_pfn(page_to_nid(page)),
139 MAX_ORDER_NR_PAGES);
140 return get_entry(base, index);
141}
142
143static int __init alloc_node_page_ext(int nid)
144{
145 struct page_ext *base;
146 unsigned long table_size;
147 unsigned long nr_pages;
148
149 nr_pages = NODE_DATA(nid)->node_spanned_pages;
150 if (!nr_pages)
151 return 0;
152
153 /*
154 * Need extra space if node range is not aligned with
155 * MAX_ORDER_NR_PAGES. When page allocator's buddy algorithm
156 * checks buddy's status, range could be out of exact node range.
157 */
158 if (!IS_ALIGNED(node_start_pfn(nid), MAX_ORDER_NR_PAGES) ||
159 !IS_ALIGNED(node_end_pfn(nid), MAX_ORDER_NR_PAGES))
160 nr_pages += MAX_ORDER_NR_PAGES;
161
162 table_size = get_entry_size() * nr_pages;
163
164 base = memblock_virt_alloc_try_nid_nopanic(
165 table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
166 BOOTMEM_ALLOC_ACCESSIBLE, nid);
167 if (!base)
168 return -ENOMEM;
169 NODE_DATA(nid)->node_page_ext = base;
170 total_usage += table_size;
171 return 0;
172}
173
174void __init page_ext_init_flatmem(void)
175{
176
177 int nid, fail;
178
179 if (!invoke_need_callbacks())
180 return;
181
182 for_each_online_node(nid) {
183 fail = alloc_node_page_ext(nid);
184 if (fail)
185 goto fail;
186 }
187 pr_info("allocated %ld bytes of page_ext\n", total_usage);
188 invoke_init_callbacks();
189 return;
190
191fail:
192 pr_crit("allocation of page_ext failed.\n");
193 panic("Out of memory");
194}
195
196#else /* CONFIG_FLAT_NODE_MEM_MAP */
197
198struct page_ext *lookup_page_ext(struct page *page)
199{
200 unsigned long pfn = page_to_pfn(page);
201 struct mem_section *section = __pfn_to_section(pfn);
202 /*
203 * The sanity checks the page allocator does upon freeing a
204 * page can reach here before the page_ext arrays are
205 * allocated when feeding a range of pages to the allocator
206 * for the first time during bootup or memory hotplug.
207 */
208 if (!section->page_ext)
209 return NULL;
210 return get_entry(section->page_ext, pfn);
211}
212
213static void *__meminit alloc_page_ext(size_t size, int nid)
214{
215 gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
216 void *addr = NULL;
217
218 addr = alloc_pages_exact_nid(nid, size, flags);
219 if (addr) {
220 kmemleak_alloc(addr, size, 1, flags);
221 return addr;
222 }
223
224 addr = vzalloc_node(size, nid);
225
226 return addr;
227}
228
229static int __meminit init_section_page_ext(unsigned long pfn, int nid)
230{
231 struct mem_section *section;
232 struct page_ext *base;
233 unsigned long table_size;
234
235 section = __pfn_to_section(pfn);
236
237 if (section->page_ext)
238 return 0;
239
240 table_size = get_entry_size() * PAGES_PER_SECTION;
241 base = alloc_page_ext(table_size, nid);
242
243 /*
244 * The value stored in section->page_ext is (base - pfn)
245 * and it does not point to the memory block allocated above,
246 * causing kmemleak false positives.
247 */
248 kmemleak_not_leak(base);
249
250 if (!base) {
251 pr_err("page ext allocation failure\n");
252 return -ENOMEM;
253 }
254
255 /*
256 * The passed "pfn" may not be aligned to SECTION. For the calculation
257 * we need to apply a mask.
258 */
259 pfn &= PAGE_SECTION_MASK;
260 section->page_ext = (void *)base - get_entry_size() * pfn;
261 total_usage += table_size;
262 return 0;
263}
264#ifdef CONFIG_MEMORY_HOTPLUG
265static void free_page_ext(void *addr)
266{
267 if (is_vmalloc_addr(addr)) {
268 vfree(addr);
269 } else {
270 struct page *page = virt_to_page(addr);
271 size_t table_size;
272
273 table_size = get_entry_size() * PAGES_PER_SECTION;
274
275 BUG_ON(PageReserved(page));
276 free_pages_exact(addr, table_size);
277 }
278}
279
280static void __free_page_ext(unsigned long pfn)
281{
282 struct mem_section *ms;
283 struct page_ext *base;
284
285 ms = __pfn_to_section(pfn);
286 if (!ms || !ms->page_ext)
287 return;
288 base = get_entry(ms->page_ext, pfn);
289 free_page_ext(base);
290 ms->page_ext = NULL;
291}
292
293static int __meminit online_page_ext(unsigned long start_pfn,
294 unsigned long nr_pages,
295 int nid)
296{
297 unsigned long start, end, pfn;
298 int fail = 0;
299
300 start = SECTION_ALIGN_DOWN(start_pfn);
301 end = SECTION_ALIGN_UP(start_pfn + nr_pages);
302
303 if (nid == -1) {
304 /*
305 * In this case, "nid" already exists and contains valid memory.
306 * "start_pfn" passed to us is a pfn which is an arg for
307 * online__pages(), and start_pfn should exist.
308 */
309 nid = pfn_to_nid(start_pfn);
310 VM_BUG_ON(!node_state(nid, N_ONLINE));
311 }
312
313 for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
314 if (!pfn_present(pfn))
315 continue;
316 fail = init_section_page_ext(pfn, nid);
317 }
318 if (!fail)
319 return 0;
320
321 /* rollback */
322 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
323 __free_page_ext(pfn);
324
325 return -ENOMEM;
326}
327
328static int __meminit offline_page_ext(unsigned long start_pfn,
329 unsigned long nr_pages, int nid)
330{
331 unsigned long start, end, pfn;
332
333 start = SECTION_ALIGN_DOWN(start_pfn);
334 end = SECTION_ALIGN_UP(start_pfn + nr_pages);
335
336 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
337 __free_page_ext(pfn);
338 return 0;
339
340}
341
342static int __meminit page_ext_callback(struct notifier_block *self,
343 unsigned long action, void *arg)
344{
345 struct memory_notify *mn = arg;
346 int ret = 0;
347
348 switch (action) {
349 case MEM_GOING_ONLINE:
350 ret = online_page_ext(mn->start_pfn,
351 mn->nr_pages, mn->status_change_nid);
352 break;
353 case MEM_OFFLINE:
354 offline_page_ext(mn->start_pfn,
355 mn->nr_pages, mn->status_change_nid);
356 break;
357 case MEM_CANCEL_ONLINE:
358 offline_page_ext(mn->start_pfn,
359 mn->nr_pages, mn->status_change_nid);
360 break;
361 case MEM_GOING_OFFLINE:
362 break;
363 case MEM_ONLINE:
364 case MEM_CANCEL_OFFLINE:
365 break;
366 }
367
368 return notifier_from_errno(ret);
369}
370
371#endif
372
373void __init page_ext_init(void)
374{
375 unsigned long pfn;
376 int nid;
377
378 if (!invoke_need_callbacks())
379 return;
380
381 for_each_node_state(nid, N_MEMORY) {
382 unsigned long start_pfn, end_pfn;
383
384 start_pfn = node_start_pfn(nid);
385 end_pfn = node_end_pfn(nid);
386 /*
387 * start_pfn and end_pfn may not be aligned to SECTION and the
388 * page->flags of out of node pages are not initialized. So we
389 * scan [start_pfn, the biggest section's pfn < end_pfn) here.
390 */
391 for (pfn = start_pfn; pfn < end_pfn;
392 pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
393
394 if (!pfn_valid(pfn))
395 continue;
396 /*
397 * Nodes's pfns can be overlapping.
398 * We know some arch can have a nodes layout such as
399 * -------------pfn-------------->
400 * N0 | N1 | N2 | N0 | N1 | N2|....
401 *
402 * Take into account DEFERRED_STRUCT_PAGE_INIT.
403 */
404 if (early_pfn_to_nid(pfn) != nid)
405 continue;
406 if (init_section_page_ext(pfn, nid))
407 goto oom;
408 cond_resched();
409 }
410 }
411 hotplug_memory_notifier(page_ext_callback, 0);
412 pr_info("allocated %ld bytes of page_ext\n", total_usage);
413 invoke_init_callbacks();
414 return;
415
416oom:
417 panic("Out of memory");
418}
419
420void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
421{
422}
423
424#endif
1// SPDX-License-Identifier: GPL-2.0
2#include <linux/mm.h>
3#include <linux/mmzone.h>
4#include <linux/memblock.h>
5#include <linux/page_ext.h>
6#include <linux/memory.h>
7#include <linux/vmalloc.h>
8#include <linux/kmemleak.h>
9#include <linux/page_owner.h>
10#include <linux/page_idle.h>
11
12/*
13 * struct page extension
14 *
15 * This is the feature to manage memory for extended data per page.
16 *
17 * Until now, we must modify struct page itself to store extra data per page.
18 * This requires rebuilding the kernel and it is really time consuming process.
19 * And, sometimes, rebuild is impossible due to third party module dependency.
20 * At last, enlarging struct page could cause un-wanted system behaviour change.
21 *
22 * This feature is intended to overcome above mentioned problems. This feature
23 * allocates memory for extended data per page in certain place rather than
24 * the struct page itself. This memory can be accessed by the accessor
25 * functions provided by this code. During the boot process, it checks whether
26 * allocation of huge chunk of memory is needed or not. If not, it avoids
27 * allocating memory at all. With this advantage, we can include this feature
28 * into the kernel in default and can avoid rebuild and solve related problems.
29 *
30 * To help these things to work well, there are two callbacks for clients. One
31 * is the need callback which is mandatory if user wants to avoid useless
32 * memory allocation at boot-time. The other is optional, init callback, which
33 * is used to do proper initialization after memory is allocated.
34 *
35 * The need callback is used to decide whether extended memory allocation is
36 * needed or not. Sometimes users want to deactivate some features in this
37 * boot and extra memory would be unneccessary. In this case, to avoid
38 * allocating huge chunk of memory, each clients represent their need of
39 * extra memory through the need callback. If one of the need callbacks
40 * returns true, it means that someone needs extra memory so that
41 * page extension core should allocates memory for page extension. If
42 * none of need callbacks return true, memory isn't needed at all in this boot
43 * and page extension core can skip to allocate memory. As result,
44 * none of memory is wasted.
45 *
46 * When need callback returns true, page_ext checks if there is a request for
47 * extra memory through size in struct page_ext_operations. If it is non-zero,
48 * extra space is allocated for each page_ext entry and offset is returned to
49 * user through offset in struct page_ext_operations.
50 *
51 * The init callback is used to do proper initialization after page extension
52 * is completely initialized. In sparse memory system, extra memory is
53 * allocated some time later than memmap is allocated. In other words, lifetime
54 * of memory for page extension isn't same with memmap for struct page.
55 * Therefore, clients can't store extra data until page extension is
56 * initialized, even if pages are allocated and used freely. This could
57 * cause inadequate state of extra data per page, so, to prevent it, client
58 * can utilize this callback to initialize the state of it correctly.
59 */
60
61static struct page_ext_operations *page_ext_ops[] = {
62#ifdef CONFIG_PAGE_OWNER
63 &page_owner_ops,
64#endif
65#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
66 &page_idle_ops,
67#endif
68};
69
70unsigned long page_ext_size = sizeof(struct page_ext);
71
72static unsigned long total_usage;
73
74static bool __init invoke_need_callbacks(void)
75{
76 int i;
77 int entries = ARRAY_SIZE(page_ext_ops);
78 bool need = false;
79
80 for (i = 0; i < entries; i++) {
81 if (page_ext_ops[i]->need && page_ext_ops[i]->need()) {
82 page_ext_ops[i]->offset = page_ext_size;
83 page_ext_size += page_ext_ops[i]->size;
84 need = true;
85 }
86 }
87
88 return need;
89}
90
91static void __init invoke_init_callbacks(void)
92{
93 int i;
94 int entries = ARRAY_SIZE(page_ext_ops);
95
96 for (i = 0; i < entries; i++) {
97 if (page_ext_ops[i]->init)
98 page_ext_ops[i]->init();
99 }
100}
101
102static inline struct page_ext *get_entry(void *base, unsigned long index)
103{
104 return base + page_ext_size * index;
105}
106
107#if !defined(CONFIG_SPARSEMEM)
108
109
110void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
111{
112 pgdat->node_page_ext = NULL;
113}
114
115struct page_ext *lookup_page_ext(const struct page *page)
116{
117 unsigned long pfn = page_to_pfn(page);
118 unsigned long index;
119 struct page_ext *base;
120
121 base = NODE_DATA(page_to_nid(page))->node_page_ext;
122 /*
123 * The sanity checks the page allocator does upon freeing a
124 * page can reach here before the page_ext arrays are
125 * allocated when feeding a range of pages to the allocator
126 * for the first time during bootup or memory hotplug.
127 */
128 if (unlikely(!base))
129 return NULL;
130 index = pfn - round_down(node_start_pfn(page_to_nid(page)),
131 MAX_ORDER_NR_PAGES);
132 return get_entry(base, index);
133}
134
135static int __init alloc_node_page_ext(int nid)
136{
137 struct page_ext *base;
138 unsigned long table_size;
139 unsigned long nr_pages;
140
141 nr_pages = NODE_DATA(nid)->node_spanned_pages;
142 if (!nr_pages)
143 return 0;
144
145 /*
146 * Need extra space if node range is not aligned with
147 * MAX_ORDER_NR_PAGES. When page allocator's buddy algorithm
148 * checks buddy's status, range could be out of exact node range.
149 */
150 if (!IS_ALIGNED(node_start_pfn(nid), MAX_ORDER_NR_PAGES) ||
151 !IS_ALIGNED(node_end_pfn(nid), MAX_ORDER_NR_PAGES))
152 nr_pages += MAX_ORDER_NR_PAGES;
153
154 table_size = page_ext_size * nr_pages;
155
156 base = memblock_alloc_try_nid(
157 table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
158 MEMBLOCK_ALLOC_ACCESSIBLE, nid);
159 if (!base)
160 return -ENOMEM;
161 NODE_DATA(nid)->node_page_ext = base;
162 total_usage += table_size;
163 return 0;
164}
165
166void __init page_ext_init_flatmem(void)
167{
168
169 int nid, fail;
170
171 if (!invoke_need_callbacks())
172 return;
173
174 for_each_online_node(nid) {
175 fail = alloc_node_page_ext(nid);
176 if (fail)
177 goto fail;
178 }
179 pr_info("allocated %ld bytes of page_ext\n", total_usage);
180 invoke_init_callbacks();
181 return;
182
183fail:
184 pr_crit("allocation of page_ext failed.\n");
185 panic("Out of memory");
186}
187
188#else /* CONFIG_FLAT_NODE_MEM_MAP */
189
190struct page_ext *lookup_page_ext(const struct page *page)
191{
192 unsigned long pfn = page_to_pfn(page);
193 struct mem_section *section = __pfn_to_section(pfn);
194 /*
195 * The sanity checks the page allocator does upon freeing a
196 * page can reach here before the page_ext arrays are
197 * allocated when feeding a range of pages to the allocator
198 * for the first time during bootup or memory hotplug.
199 */
200 if (!section->page_ext)
201 return NULL;
202 return get_entry(section->page_ext, pfn);
203}
204
205static void *__meminit alloc_page_ext(size_t size, int nid)
206{
207 gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
208 void *addr = NULL;
209
210 addr = alloc_pages_exact_nid(nid, size, flags);
211 if (addr) {
212 kmemleak_alloc(addr, size, 1, flags);
213 return addr;
214 }
215
216 addr = vzalloc_node(size, nid);
217
218 return addr;
219}
220
221static int __meminit init_section_page_ext(unsigned long pfn, int nid)
222{
223 struct mem_section *section;
224 struct page_ext *base;
225 unsigned long table_size;
226
227 section = __pfn_to_section(pfn);
228
229 if (section->page_ext)
230 return 0;
231
232 table_size = page_ext_size * PAGES_PER_SECTION;
233 base = alloc_page_ext(table_size, nid);
234
235 /*
236 * The value stored in section->page_ext is (base - pfn)
237 * and it does not point to the memory block allocated above,
238 * causing kmemleak false positives.
239 */
240 kmemleak_not_leak(base);
241
242 if (!base) {
243 pr_err("page ext allocation failure\n");
244 return -ENOMEM;
245 }
246
247 /*
248 * The passed "pfn" may not be aligned to SECTION. For the calculation
249 * we need to apply a mask.
250 */
251 pfn &= PAGE_SECTION_MASK;
252 section->page_ext = (void *)base - page_ext_size * pfn;
253 total_usage += table_size;
254 return 0;
255}
256#ifdef CONFIG_MEMORY_HOTPLUG
257static void free_page_ext(void *addr)
258{
259 if (is_vmalloc_addr(addr)) {
260 vfree(addr);
261 } else {
262 struct page *page = virt_to_page(addr);
263 size_t table_size;
264
265 table_size = page_ext_size * PAGES_PER_SECTION;
266
267 BUG_ON(PageReserved(page));
268 kmemleak_free(addr);
269 free_pages_exact(addr, table_size);
270 }
271}
272
273static void __free_page_ext(unsigned long pfn)
274{
275 struct mem_section *ms;
276 struct page_ext *base;
277
278 ms = __pfn_to_section(pfn);
279 if (!ms || !ms->page_ext)
280 return;
281 base = get_entry(ms->page_ext, pfn);
282 free_page_ext(base);
283 ms->page_ext = NULL;
284}
285
286static int __meminit online_page_ext(unsigned long start_pfn,
287 unsigned long nr_pages,
288 int nid)
289{
290 unsigned long start, end, pfn;
291 int fail = 0;
292
293 start = SECTION_ALIGN_DOWN(start_pfn);
294 end = SECTION_ALIGN_UP(start_pfn + nr_pages);
295
296 if (nid == NUMA_NO_NODE) {
297 /*
298 * In this case, "nid" already exists and contains valid memory.
299 * "start_pfn" passed to us is a pfn which is an arg for
300 * online__pages(), and start_pfn should exist.
301 */
302 nid = pfn_to_nid(start_pfn);
303 VM_BUG_ON(!node_state(nid, N_ONLINE));
304 }
305
306 for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION)
307 fail = init_section_page_ext(pfn, nid);
308 if (!fail)
309 return 0;
310
311 /* rollback */
312 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
313 __free_page_ext(pfn);
314
315 return -ENOMEM;
316}
317
318static int __meminit offline_page_ext(unsigned long start_pfn,
319 unsigned long nr_pages, int nid)
320{
321 unsigned long start, end, pfn;
322
323 start = SECTION_ALIGN_DOWN(start_pfn);
324 end = SECTION_ALIGN_UP(start_pfn + nr_pages);
325
326 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
327 __free_page_ext(pfn);
328 return 0;
329
330}
331
332static int __meminit page_ext_callback(struct notifier_block *self,
333 unsigned long action, void *arg)
334{
335 struct memory_notify *mn = arg;
336 int ret = 0;
337
338 switch (action) {
339 case MEM_GOING_ONLINE:
340 ret = online_page_ext(mn->start_pfn,
341 mn->nr_pages, mn->status_change_nid);
342 break;
343 case MEM_OFFLINE:
344 offline_page_ext(mn->start_pfn,
345 mn->nr_pages, mn->status_change_nid);
346 break;
347 case MEM_CANCEL_ONLINE:
348 offline_page_ext(mn->start_pfn,
349 mn->nr_pages, mn->status_change_nid);
350 break;
351 case MEM_GOING_OFFLINE:
352 break;
353 case MEM_ONLINE:
354 case MEM_CANCEL_OFFLINE:
355 break;
356 }
357
358 return notifier_from_errno(ret);
359}
360
361#endif
362
363void __init page_ext_init(void)
364{
365 unsigned long pfn;
366 int nid;
367
368 if (!invoke_need_callbacks())
369 return;
370
371 for_each_node_state(nid, N_MEMORY) {
372 unsigned long start_pfn, end_pfn;
373
374 start_pfn = node_start_pfn(nid);
375 end_pfn = node_end_pfn(nid);
376 /*
377 * start_pfn and end_pfn may not be aligned to SECTION and the
378 * page->flags of out of node pages are not initialized. So we
379 * scan [start_pfn, the biggest section's pfn < end_pfn) here.
380 */
381 for (pfn = start_pfn; pfn < end_pfn;
382 pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
383
384 if (!pfn_valid(pfn))
385 continue;
386 /*
387 * Nodes's pfns can be overlapping.
388 * We know some arch can have a nodes layout such as
389 * -------------pfn-------------->
390 * N0 | N1 | N2 | N0 | N1 | N2|....
391 */
392 if (pfn_to_nid(pfn) != nid)
393 continue;
394 if (init_section_page_ext(pfn, nid))
395 goto oom;
396 cond_resched();
397 }
398 }
399 hotplug_memory_notifier(page_ext_callback, 0);
400 pr_info("allocated %ld bytes of page_ext\n", total_usage);
401 invoke_init_callbacks();
402 return;
403
404oom:
405 panic("Out of memory");
406}
407
408void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
409{
410}
411
412#endif