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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 if (!pfn_present(pfn))
308 continue;
309 fail = init_section_page_ext(pfn, nid);
310 }
311 if (!fail)
312 return 0;
313
314 /* rollback */
315 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
316 __free_page_ext(pfn);
317
318 return -ENOMEM;
319}
320
321static int __meminit offline_page_ext(unsigned long start_pfn,
322 unsigned long nr_pages, int nid)
323{
324 unsigned long start, end, pfn;
325
326 start = SECTION_ALIGN_DOWN(start_pfn);
327 end = SECTION_ALIGN_UP(start_pfn + nr_pages);
328
329 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
330 __free_page_ext(pfn);
331 return 0;
332
333}
334
335static int __meminit page_ext_callback(struct notifier_block *self,
336 unsigned long action, void *arg)
337{
338 struct memory_notify *mn = arg;
339 int ret = 0;
340
341 switch (action) {
342 case MEM_GOING_ONLINE:
343 ret = online_page_ext(mn->start_pfn,
344 mn->nr_pages, mn->status_change_nid);
345 break;
346 case MEM_OFFLINE:
347 offline_page_ext(mn->start_pfn,
348 mn->nr_pages, mn->status_change_nid);
349 break;
350 case MEM_CANCEL_ONLINE:
351 offline_page_ext(mn->start_pfn,
352 mn->nr_pages, mn->status_change_nid);
353 break;
354 case MEM_GOING_OFFLINE:
355 break;
356 case MEM_ONLINE:
357 case MEM_CANCEL_OFFLINE:
358 break;
359 }
360
361 return notifier_from_errno(ret);
362}
363
364#endif
365
366void __init page_ext_init(void)
367{
368 unsigned long pfn;
369 int nid;
370
371 if (!invoke_need_callbacks())
372 return;
373
374 for_each_node_state(nid, N_MEMORY) {
375 unsigned long start_pfn, end_pfn;
376
377 start_pfn = node_start_pfn(nid);
378 end_pfn = node_end_pfn(nid);
379 /*
380 * start_pfn and end_pfn may not be aligned to SECTION and the
381 * page->flags of out of node pages are not initialized. So we
382 * scan [start_pfn, the biggest section's pfn < end_pfn) here.
383 */
384 for (pfn = start_pfn; pfn < end_pfn;
385 pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
386
387 if (!pfn_valid(pfn))
388 continue;
389 /*
390 * Nodes's pfns can be overlapping.
391 * We know some arch can have a nodes layout such as
392 * -------------pfn-------------->
393 * N0 | N1 | N2 | N0 | N1 | N2|....
394 */
395 if (pfn_to_nid(pfn) != nid)
396 continue;
397 if (init_section_page_ext(pfn, nid))
398 goto oom;
399 cond_resched();
400 }
401 }
402 hotplug_memory_notifier(page_ext_callback, 0);
403 pr_info("allocated %ld bytes of page_ext\n", total_usage);
404 invoke_init_callbacks();
405 return;
406
407oom:
408 panic("Out of memory");
409}
410
411void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
412{
413}
414
415#endif
1#include <linux/mm.h>
2#include <linux/mmzone.h>
3#include <linux/bootmem.h>
4#include <linux/page_ext.h>
5#include <linux/memory.h>
6#include <linux/vmalloc.h>
7#include <linux/kmemleak.h>
8#include <linux/page_owner.h>
9#include <linux/page_idle.h>
10
11/*
12 * struct page extension
13 *
14 * This is the feature to manage memory for extended data per page.
15 *
16 * Until now, we must modify struct page itself to store extra data per page.
17 * This requires rebuilding the kernel and it is really time consuming process.
18 * And, sometimes, rebuild is impossible due to third party module dependency.
19 * At last, enlarging struct page could cause un-wanted system behaviour change.
20 *
21 * This feature is intended to overcome above mentioned problems. This feature
22 * allocates memory for extended data per page in certain place rather than
23 * the struct page itself. This memory can be accessed by the accessor
24 * functions provided by this code. During the boot process, it checks whether
25 * allocation of huge chunk of memory is needed or not. If not, it avoids
26 * allocating memory at all. With this advantage, we can include this feature
27 * into the kernel in default and can avoid rebuild and solve related problems.
28 *
29 * To help these things to work well, there are two callbacks for clients. One
30 * is the need callback which is mandatory if user wants to avoid useless
31 * memory allocation at boot-time. The other is optional, init callback, which
32 * is used to do proper initialization after memory is allocated.
33 *
34 * The need callback is used to decide whether extended memory allocation is
35 * needed or not. Sometimes users want to deactivate some features in this
36 * boot and extra memory would be unneccessary. In this case, to avoid
37 * allocating huge chunk of memory, each clients represent their need of
38 * extra memory through the need callback. If one of the need callbacks
39 * returns true, it means that someone needs extra memory so that
40 * page extension core should allocates memory for page extension. If
41 * none of need callbacks return true, memory isn't needed at all in this boot
42 * and page extension core can skip to allocate memory. As result,
43 * none of memory is wasted.
44 *
45 * When need callback returns true, page_ext checks if there is a request for
46 * extra memory through size in struct page_ext_operations. If it is non-zero,
47 * extra space is allocated for each page_ext entry and offset is returned to
48 * user through offset in struct page_ext_operations.
49 *
50 * The init callback is used to do proper initialization after page extension
51 * is completely initialized. In sparse memory system, extra memory is
52 * allocated some time later than memmap is allocated. In other words, lifetime
53 * of memory for page extension isn't same with memmap for struct page.
54 * Therefore, clients can't store extra data until page extension is
55 * initialized, even if pages are allocated and used freely. This could
56 * cause inadequate state of extra data per page, so, to prevent it, client
57 * can utilize this callback to initialize the state of it correctly.
58 */
59
60static struct page_ext_operations *page_ext_ops[] = {
61 &debug_guardpage_ops,
62#ifdef CONFIG_PAGE_POISONING
63 &page_poisoning_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#if defined(CONFIG_DEBUG_VM) || defined(CONFIG_PAGE_POISONING)
131 /*
132 * The sanity checks the page allocator does upon freeing a
133 * page can reach here before the page_ext arrays are
134 * allocated when feeding a range of pages to the allocator
135 * for the first time during bootup or memory hotplug.
136 *
137 * This check is also necessary for ensuring page poisoning
138 * works as expected when enabled
139 */
140 if (unlikely(!base))
141 return NULL;
142#endif
143 index = pfn - round_down(node_start_pfn(page_to_nid(page)),
144 MAX_ORDER_NR_PAGES);
145 return get_entry(base, index);
146}
147
148static int __init alloc_node_page_ext(int nid)
149{
150 struct page_ext *base;
151 unsigned long table_size;
152 unsigned long nr_pages;
153
154 nr_pages = NODE_DATA(nid)->node_spanned_pages;
155 if (!nr_pages)
156 return 0;
157
158 /*
159 * Need extra space if node range is not aligned with
160 * MAX_ORDER_NR_PAGES. When page allocator's buddy algorithm
161 * checks buddy's status, range could be out of exact node range.
162 */
163 if (!IS_ALIGNED(node_start_pfn(nid), MAX_ORDER_NR_PAGES) ||
164 !IS_ALIGNED(node_end_pfn(nid), MAX_ORDER_NR_PAGES))
165 nr_pages += MAX_ORDER_NR_PAGES;
166
167 table_size = get_entry_size() * nr_pages;
168
169 base = memblock_virt_alloc_try_nid_nopanic(
170 table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
171 BOOTMEM_ALLOC_ACCESSIBLE, nid);
172 if (!base)
173 return -ENOMEM;
174 NODE_DATA(nid)->node_page_ext = base;
175 total_usage += table_size;
176 return 0;
177}
178
179void __init page_ext_init_flatmem(void)
180{
181
182 int nid, fail;
183
184 if (!invoke_need_callbacks())
185 return;
186
187 for_each_online_node(nid) {
188 fail = alloc_node_page_ext(nid);
189 if (fail)
190 goto fail;
191 }
192 pr_info("allocated %ld bytes of page_ext\n", total_usage);
193 invoke_init_callbacks();
194 return;
195
196fail:
197 pr_crit("allocation of page_ext failed.\n");
198 panic("Out of memory");
199}
200
201#else /* CONFIG_FLAT_NODE_MEM_MAP */
202
203struct page_ext *lookup_page_ext(struct page *page)
204{
205 unsigned long pfn = page_to_pfn(page);
206 struct mem_section *section = __pfn_to_section(pfn);
207#if defined(CONFIG_DEBUG_VM) || defined(CONFIG_PAGE_POISONING)
208 /*
209 * The sanity checks the page allocator does upon freeing a
210 * page can reach here before the page_ext arrays are
211 * allocated when feeding a range of pages to the allocator
212 * for the first time during bootup or memory hotplug.
213 *
214 * This check is also necessary for ensuring page poisoning
215 * works as expected when enabled
216 */
217 if (!section->page_ext)
218 return NULL;
219#endif
220 return get_entry(section->page_ext, pfn);
221}
222
223static void *__meminit alloc_page_ext(size_t size, int nid)
224{
225 gfp_t flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN;
226 void *addr = NULL;
227
228 addr = alloc_pages_exact_nid(nid, size, flags);
229 if (addr) {
230 kmemleak_alloc(addr, size, 1, flags);
231 return addr;
232 }
233
234 if (node_state(nid, N_HIGH_MEMORY))
235 addr = vzalloc_node(size, nid);
236 else
237 addr = vzalloc(size);
238
239 return addr;
240}
241
242static int __meminit init_section_page_ext(unsigned long pfn, int nid)
243{
244 struct mem_section *section;
245 struct page_ext *base;
246 unsigned long table_size;
247
248 section = __pfn_to_section(pfn);
249
250 if (section->page_ext)
251 return 0;
252
253 table_size = get_entry_size() * PAGES_PER_SECTION;
254 base = alloc_page_ext(table_size, nid);
255
256 /*
257 * The value stored in section->page_ext is (base - pfn)
258 * and it does not point to the memory block allocated above,
259 * causing kmemleak false positives.
260 */
261 kmemleak_not_leak(base);
262
263 if (!base) {
264 pr_err("page ext allocation failure\n");
265 return -ENOMEM;
266 }
267
268 /*
269 * The passed "pfn" may not be aligned to SECTION. For the calculation
270 * we need to apply a mask.
271 */
272 pfn &= PAGE_SECTION_MASK;
273 section->page_ext = (void *)base - get_entry_size() * pfn;
274 total_usage += table_size;
275 return 0;
276}
277#ifdef CONFIG_MEMORY_HOTPLUG
278static void free_page_ext(void *addr)
279{
280 if (is_vmalloc_addr(addr)) {
281 vfree(addr);
282 } else {
283 struct page *page = virt_to_page(addr);
284 size_t table_size;
285
286 table_size = get_entry_size() * PAGES_PER_SECTION;
287
288 BUG_ON(PageReserved(page));
289 free_pages_exact(addr, table_size);
290 }
291}
292
293static void __free_page_ext(unsigned long pfn)
294{
295 struct mem_section *ms;
296 struct page_ext *base;
297
298 ms = __pfn_to_section(pfn);
299 if (!ms || !ms->page_ext)
300 return;
301 base = get_entry(ms->page_ext, pfn);
302 free_page_ext(base);
303 ms->page_ext = NULL;
304}
305
306static int __meminit online_page_ext(unsigned long start_pfn,
307 unsigned long nr_pages,
308 int nid)
309{
310 unsigned long start, end, pfn;
311 int fail = 0;
312
313 start = SECTION_ALIGN_DOWN(start_pfn);
314 end = SECTION_ALIGN_UP(start_pfn + nr_pages);
315
316 if (nid == -1) {
317 /*
318 * In this case, "nid" already exists and contains valid memory.
319 * "start_pfn" passed to us is a pfn which is an arg for
320 * online__pages(), and start_pfn should exist.
321 */
322 nid = pfn_to_nid(start_pfn);
323 VM_BUG_ON(!node_state(nid, N_ONLINE));
324 }
325
326 for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
327 if (!pfn_present(pfn))
328 continue;
329 fail = init_section_page_ext(pfn, nid);
330 }
331 if (!fail)
332 return 0;
333
334 /* rollback */
335 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
336 __free_page_ext(pfn);
337
338 return -ENOMEM;
339}
340
341static int __meminit offline_page_ext(unsigned long start_pfn,
342 unsigned long nr_pages, int nid)
343{
344 unsigned long start, end, pfn;
345
346 start = SECTION_ALIGN_DOWN(start_pfn);
347 end = SECTION_ALIGN_UP(start_pfn + nr_pages);
348
349 for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
350 __free_page_ext(pfn);
351 return 0;
352
353}
354
355static int __meminit page_ext_callback(struct notifier_block *self,
356 unsigned long action, void *arg)
357{
358 struct memory_notify *mn = arg;
359 int ret = 0;
360
361 switch (action) {
362 case MEM_GOING_ONLINE:
363 ret = online_page_ext(mn->start_pfn,
364 mn->nr_pages, mn->status_change_nid);
365 break;
366 case MEM_OFFLINE:
367 offline_page_ext(mn->start_pfn,
368 mn->nr_pages, mn->status_change_nid);
369 break;
370 case MEM_CANCEL_ONLINE:
371 offline_page_ext(mn->start_pfn,
372 mn->nr_pages, mn->status_change_nid);
373 break;
374 case MEM_GOING_OFFLINE:
375 break;
376 case MEM_ONLINE:
377 case MEM_CANCEL_OFFLINE:
378 break;
379 }
380
381 return notifier_from_errno(ret);
382}
383
384#endif
385
386void __init page_ext_init(void)
387{
388 unsigned long pfn;
389 int nid;
390
391 if (!invoke_need_callbacks())
392 return;
393
394 for_each_node_state(nid, N_MEMORY) {
395 unsigned long start_pfn, end_pfn;
396
397 start_pfn = node_start_pfn(nid);
398 end_pfn = node_end_pfn(nid);
399 /*
400 * start_pfn and end_pfn may not be aligned to SECTION and the
401 * page->flags of out of node pages are not initialized. So we
402 * scan [start_pfn, the biggest section's pfn < end_pfn) here.
403 */
404 for (pfn = start_pfn; pfn < end_pfn;
405 pfn = ALIGN(pfn + 1, PAGES_PER_SECTION)) {
406
407 if (!pfn_valid(pfn))
408 continue;
409 /*
410 * Nodes's pfns can be overlapping.
411 * We know some arch can have a nodes layout such as
412 * -------------pfn-------------->
413 * N0 | N1 | N2 | N0 | N1 | N2|....
414 *
415 * Take into account DEFERRED_STRUCT_PAGE_INIT.
416 */
417 if (early_pfn_to_nid(pfn) != nid)
418 continue;
419 if (init_section_page_ext(pfn, nid))
420 goto oom;
421 }
422 }
423 hotplug_memory_notifier(page_ext_callback, 0);
424 pr_info("allocated %ld bytes of page_ext\n", total_usage);
425 invoke_init_callbacks();
426 return;
427
428oom:
429 panic("Out of memory");
430}
431
432void __meminit pgdat_page_ext_init(struct pglist_data *pgdat)
433{
434}
435
436#endif