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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/delay.h> |
26 | #include <linux/migrate.h> |
27 | #include <linux/page-isolation.h> |
28 | #include <linux/pfn.h> |
29 | #include <linux/suspend.h> |
30 | #include <linux/mm_inline.h> |
31 | #include <linux/firmware-map.h> |
32 | |
33 | #include <asm/tlbflush.h> |
34 | |
35 | #include "internal.h" |
36 | |
37 | DEFINE_MUTEX(mem_hotplug_mutex); |
38 | |
39 | void lock_memory_hotplug(void) |
40 | { |
41 | mutex_lock(&mem_hotplug_mutex); |
42 | |
43 | /* for exclusive hibernation if CONFIG_HIBERNATION=y */ |
44 | lock_system_sleep(); |
45 | } |
46 | |
47 | void unlock_memory_hotplug(void) |
48 | { |
49 | unlock_system_sleep(); |
50 | mutex_unlock(&mem_hotplug_mutex); |
51 | } |
52 | |
53 | |
54 | /* add this memory to iomem resource */ |
55 | static struct resource *register_memory_resource(u64 start, u64 size) |
56 | { |
57 | struct resource *res; |
58 | res = kzalloc(sizeof(struct resource), GFP_KERNEL); |
59 | BUG_ON(!res); |
60 | |
61 | res->name = "System RAM"; |
62 | res->start = start; |
63 | res->end = start + size - 1; |
64 | res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; |
65 | if (request_resource(&iomem_resource, res) < 0) { |
66 | printk("System RAM resource %llx - %llx cannot be added\n", |
67 | (unsigned long long)res->start, (unsigned long long)res->end); |
68 | kfree(res); |
69 | res = NULL; |
70 | } |
71 | return res; |
72 | } |
73 | |
74 | static void release_memory_resource(struct resource *res) |
75 | { |
76 | if (!res) |
77 | return; |
78 | release_resource(res); |
79 | kfree(res); |
80 | return; |
81 | } |
82 | |
83 | #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE |
84 | #ifndef CONFIG_SPARSEMEM_VMEMMAP |
85 | static void get_page_bootmem(unsigned long info, struct page *page, |
86 | unsigned long type) |
87 | { |
88 | page->lru.next = (struct list_head *) type; |
89 | SetPagePrivate(page); |
90 | set_page_private(page, info); |
91 | atomic_inc(&page->_count); |
92 | } |
93 | |
94 | /* reference to __meminit __free_pages_bootmem is valid |
95 | * so use __ref to tell modpost not to generate a warning */ |
96 | void __ref put_page_bootmem(struct page *page) |
97 | { |
98 | unsigned long type; |
99 | |
100 | type = (unsigned long) page->lru.next; |
101 | BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || |
102 | type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE); |
103 | |
104 | if (atomic_dec_return(&page->_count) == 1) { |
105 | ClearPagePrivate(page); |
106 | set_page_private(page, 0); |
107 | INIT_LIST_HEAD(&page->lru); |
108 | __free_pages_bootmem(page, 0); |
109 | } |
110 | |
111 | } |
112 | |
113 | static void register_page_bootmem_info_section(unsigned long start_pfn) |
114 | { |
115 | unsigned long *usemap, mapsize, section_nr, i; |
116 | struct mem_section *ms; |
117 | struct page *page, *memmap; |
118 | |
119 | if (!pfn_valid(start_pfn)) |
120 | return; |
121 | |
122 | section_nr = pfn_to_section_nr(start_pfn); |
123 | ms = __nr_to_section(section_nr); |
124 | |
125 | /* Get section's memmap address */ |
126 | memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); |
127 | |
128 | /* |
129 | * Get page for the memmap's phys address |
130 | * XXX: need more consideration for sparse_vmemmap... |
131 | */ |
132 | page = virt_to_page(memmap); |
133 | mapsize = sizeof(struct page) * PAGES_PER_SECTION; |
134 | mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT; |
135 | |
136 | /* remember memmap's page */ |
137 | for (i = 0; i < mapsize; i++, page++) |
138 | get_page_bootmem(section_nr, page, SECTION_INFO); |
139 | |
140 | usemap = __nr_to_section(section_nr)->pageblock_flags; |
141 | page = virt_to_page(usemap); |
142 | |
143 | mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; |
144 | |
145 | for (i = 0; i < mapsize; i++, page++) |
146 | get_page_bootmem(section_nr, page, MIX_SECTION_INFO); |
147 | |
148 | } |
149 | |
150 | void register_page_bootmem_info_node(struct pglist_data *pgdat) |
151 | { |
152 | unsigned long i, pfn, end_pfn, nr_pages; |
153 | int node = pgdat->node_id; |
154 | struct page *page; |
155 | struct zone *zone; |
156 | |
157 | nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT; |
158 | page = virt_to_page(pgdat); |
159 | |
160 | for (i = 0; i < nr_pages; i++, page++) |
161 | get_page_bootmem(node, page, NODE_INFO); |
162 | |
163 | zone = &pgdat->node_zones[0]; |
164 | for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) { |
165 | if (zone->wait_table) { |
166 | nr_pages = zone->wait_table_hash_nr_entries |
167 | * sizeof(wait_queue_head_t); |
168 | nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT; |
169 | page = virt_to_page(zone->wait_table); |
170 | |
171 | for (i = 0; i < nr_pages; i++, page++) |
172 | get_page_bootmem(node, page, NODE_INFO); |
173 | } |
174 | } |
175 | |
176 | pfn = pgdat->node_start_pfn; |
177 | end_pfn = pfn + pgdat->node_spanned_pages; |
178 | |
179 | /* register_section info */ |
180 | for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) |
181 | register_page_bootmem_info_section(pfn); |
182 | |
183 | } |
184 | #endif /* !CONFIG_SPARSEMEM_VMEMMAP */ |
185 | |
186 | static void grow_zone_span(struct zone *zone, unsigned long start_pfn, |
187 | unsigned long end_pfn) |
188 | { |
189 | unsigned long old_zone_end_pfn; |
190 | |
191 | zone_span_writelock(zone); |
192 | |
193 | old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; |
194 | if (start_pfn < zone->zone_start_pfn) |
195 | zone->zone_start_pfn = start_pfn; |
196 | |
197 | zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - |
198 | zone->zone_start_pfn; |
199 | |
200 | zone_span_writeunlock(zone); |
201 | } |
202 | |
203 | static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn, |
204 | unsigned long end_pfn) |
205 | { |
206 | unsigned long old_pgdat_end_pfn = |
207 | pgdat->node_start_pfn + pgdat->node_spanned_pages; |
208 | |
209 | if (start_pfn < pgdat->node_start_pfn) |
210 | pgdat->node_start_pfn = start_pfn; |
211 | |
212 | pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - |
213 | pgdat->node_start_pfn; |
214 | } |
215 | |
216 | static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn) |
217 | { |
218 | struct pglist_data *pgdat = zone->zone_pgdat; |
219 | int nr_pages = PAGES_PER_SECTION; |
220 | int nid = pgdat->node_id; |
221 | int zone_type; |
222 | unsigned long flags; |
223 | |
224 | zone_type = zone - pgdat->node_zones; |
225 | if (!zone->wait_table) { |
226 | int ret; |
227 | |
228 | ret = init_currently_empty_zone(zone, phys_start_pfn, |
229 | nr_pages, MEMMAP_HOTPLUG); |
230 | if (ret) |
231 | return ret; |
232 | } |
233 | pgdat_resize_lock(zone->zone_pgdat, &flags); |
234 | grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages); |
235 | grow_pgdat_span(zone->zone_pgdat, phys_start_pfn, |
236 | phys_start_pfn + nr_pages); |
237 | pgdat_resize_unlock(zone->zone_pgdat, &flags); |
238 | memmap_init_zone(nr_pages, nid, zone_type, |
239 | phys_start_pfn, MEMMAP_HOTPLUG); |
240 | return 0; |
241 | } |
242 | |
243 | static int __meminit __add_section(int nid, struct zone *zone, |
244 | unsigned long phys_start_pfn) |
245 | { |
246 | int nr_pages = PAGES_PER_SECTION; |
247 | int ret; |
248 | |
249 | if (pfn_valid(phys_start_pfn)) |
250 | return -EEXIST; |
251 | |
252 | ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); |
253 | |
254 | if (ret < 0) |
255 | return ret; |
256 | |
257 | ret = __add_zone(zone, phys_start_pfn); |
258 | |
259 | if (ret < 0) |
260 | return ret; |
261 | |
262 | return register_new_memory(nid, __pfn_to_section(phys_start_pfn)); |
263 | } |
264 | |
265 | #ifdef CONFIG_SPARSEMEM_VMEMMAP |
266 | static int __remove_section(struct zone *zone, struct mem_section *ms) |
267 | { |
268 | /* |
269 | * XXX: Freeing memmap with vmemmap is not implement yet. |
270 | * This should be removed later. |
271 | */ |
272 | return -EBUSY; |
273 | } |
274 | #else |
275 | static int __remove_section(struct zone *zone, struct mem_section *ms) |
276 | { |
277 | unsigned long flags; |
278 | struct pglist_data *pgdat = zone->zone_pgdat; |
279 | int ret = -EINVAL; |
280 | |
281 | if (!valid_section(ms)) |
282 | return ret; |
283 | |
284 | ret = unregister_memory_section(ms); |
285 | if (ret) |
286 | return ret; |
287 | |
288 | pgdat_resize_lock(pgdat, &flags); |
289 | sparse_remove_one_section(zone, ms); |
290 | pgdat_resize_unlock(pgdat, &flags); |
291 | return 0; |
292 | } |
293 | #endif |
294 | |
295 | /* |
296 | * Reasonably generic function for adding memory. It is |
297 | * expected that archs that support memory hotplug will |
298 | * call this function after deciding the zone to which to |
299 | * add the new pages. |
300 | */ |
301 | int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn, |
302 | unsigned long nr_pages) |
303 | { |
304 | unsigned long i; |
305 | int err = 0; |
306 | int start_sec, end_sec; |
307 | /* during initialize mem_map, align hot-added range to section */ |
308 | start_sec = pfn_to_section_nr(phys_start_pfn); |
309 | end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); |
310 | |
311 | for (i = start_sec; i <= end_sec; i++) { |
312 | err = __add_section(nid, zone, i << PFN_SECTION_SHIFT); |
313 | |
314 | /* |
315 | * EEXIST is finally dealt with by ioresource collision |
316 | * check. see add_memory() => register_memory_resource() |
317 | * Warning will be printed if there is collision. |
318 | */ |
319 | if (err && (err != -EEXIST)) |
320 | break; |
321 | err = 0; |
322 | } |
323 | |
324 | return err; |
325 | } |
326 | EXPORT_SYMBOL_GPL(__add_pages); |
327 | |
328 | /** |
329 | * __remove_pages() - remove sections of pages from a zone |
330 | * @zone: zone from which pages need to be removed |
331 | * @phys_start_pfn: starting pageframe (must be aligned to start of a section) |
332 | * @nr_pages: number of pages to remove (must be multiple of section size) |
333 | * |
334 | * Generic helper function to remove section mappings and sysfs entries |
335 | * for the section of the memory we are removing. Caller needs to make |
336 | * sure that pages are marked reserved and zones are adjust properly by |
337 | * calling offline_pages(). |
338 | */ |
339 | int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, |
340 | unsigned long nr_pages) |
341 | { |
342 | unsigned long i, ret = 0; |
343 | int sections_to_remove; |
344 | |
345 | /* |
346 | * We can only remove entire sections |
347 | */ |
348 | BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); |
349 | BUG_ON(nr_pages % PAGES_PER_SECTION); |
350 | |
351 | sections_to_remove = nr_pages / PAGES_PER_SECTION; |
352 | for (i = 0; i < sections_to_remove; i++) { |
353 | unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; |
354 | release_mem_region(pfn << PAGE_SHIFT, |
355 | PAGES_PER_SECTION << PAGE_SHIFT); |
356 | ret = __remove_section(zone, __pfn_to_section(pfn)); |
357 | if (ret) |
358 | break; |
359 | } |
360 | return ret; |
361 | } |
362 | EXPORT_SYMBOL_GPL(__remove_pages); |
363 | |
364 | void online_page(struct page *page) |
365 | { |
366 | unsigned long pfn = page_to_pfn(page); |
367 | |
368 | totalram_pages++; |
369 | if (pfn >= num_physpages) |
370 | num_physpages = pfn + 1; |
371 | |
372 | #ifdef CONFIG_HIGHMEM |
373 | if (PageHighMem(page)) |
374 | totalhigh_pages++; |
375 | #endif |
376 | |
377 | #ifdef CONFIG_FLATMEM |
378 | max_mapnr = max(page_to_pfn(page), max_mapnr); |
379 | #endif |
380 | |
381 | ClearPageReserved(page); |
382 | init_page_count(page); |
383 | __free_page(page); |
384 | } |
385 | |
386 | static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, |
387 | void *arg) |
388 | { |
389 | unsigned long i; |
390 | unsigned long onlined_pages = *(unsigned long *)arg; |
391 | struct page *page; |
392 | if (PageReserved(pfn_to_page(start_pfn))) |
393 | for (i = 0; i < nr_pages; i++) { |
394 | page = pfn_to_page(start_pfn + i); |
395 | online_page(page); |
396 | onlined_pages++; |
397 | } |
398 | *(unsigned long *)arg = onlined_pages; |
399 | return 0; |
400 | } |
401 | |
402 | |
403 | int online_pages(unsigned long pfn, unsigned long nr_pages) |
404 | { |
405 | unsigned long onlined_pages = 0; |
406 | struct zone *zone; |
407 | int need_zonelists_rebuild = 0; |
408 | int nid; |
409 | int ret; |
410 | struct memory_notify arg; |
411 | |
412 | lock_memory_hotplug(); |
413 | arg.start_pfn = pfn; |
414 | arg.nr_pages = nr_pages; |
415 | arg.status_change_nid = -1; |
416 | |
417 | nid = page_to_nid(pfn_to_page(pfn)); |
418 | if (node_present_pages(nid) == 0) |
419 | arg.status_change_nid = nid; |
420 | |
421 | ret = memory_notify(MEM_GOING_ONLINE, &arg); |
422 | ret = notifier_to_errno(ret); |
423 | if (ret) { |
424 | memory_notify(MEM_CANCEL_ONLINE, &arg); |
425 | unlock_memory_hotplug(); |
426 | return ret; |
427 | } |
428 | /* |
429 | * This doesn't need a lock to do pfn_to_page(). |
430 | * The section can't be removed here because of the |
431 | * memory_block->state_mutex. |
432 | */ |
433 | zone = page_zone(pfn_to_page(pfn)); |
434 | /* |
435 | * If this zone is not populated, then it is not in zonelist. |
436 | * This means the page allocator ignores this zone. |
437 | * So, zonelist must be updated after online. |
438 | */ |
439 | mutex_lock(&zonelists_mutex); |
440 | if (!populated_zone(zone)) |
441 | need_zonelists_rebuild = 1; |
442 | |
443 | ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages, |
444 | online_pages_range); |
445 | if (ret) { |
446 | mutex_unlock(&zonelists_mutex); |
447 | printk(KERN_DEBUG "online_pages %lx at %lx failed\n", |
448 | nr_pages, pfn); |
449 | memory_notify(MEM_CANCEL_ONLINE, &arg); |
450 | unlock_memory_hotplug(); |
451 | return ret; |
452 | } |
453 | |
454 | zone->present_pages += onlined_pages; |
455 | zone->zone_pgdat->node_present_pages += onlined_pages; |
456 | if (need_zonelists_rebuild) |
457 | build_all_zonelists(zone); |
458 | else |
459 | zone_pcp_update(zone); |
460 | |
461 | mutex_unlock(&zonelists_mutex); |
462 | setup_per_zone_wmarks(); |
463 | calculate_zone_inactive_ratio(zone); |
464 | if (onlined_pages) { |
465 | kswapd_run(zone_to_nid(zone)); |
466 | node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); |
467 | } |
468 | |
469 | vm_total_pages = nr_free_pagecache_pages(); |
470 | |
471 | writeback_set_ratelimit(); |
472 | |
473 | if (onlined_pages) |
474 | memory_notify(MEM_ONLINE, &arg); |
475 | unlock_memory_hotplug(); |
476 | |
477 | return 0; |
478 | } |
479 | #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ |
480 | |
481 | /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ |
482 | static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) |
483 | { |
484 | struct pglist_data *pgdat; |
485 | unsigned long zones_size[MAX_NR_ZONES] = {0}; |
486 | unsigned long zholes_size[MAX_NR_ZONES] = {0}; |
487 | unsigned long start_pfn = start >> PAGE_SHIFT; |
488 | |
489 | pgdat = arch_alloc_nodedata(nid); |
490 | if (!pgdat) |
491 | return NULL; |
492 | |
493 | arch_refresh_nodedata(nid, pgdat); |
494 | |
495 | /* we can use NODE_DATA(nid) from here */ |
496 | |
497 | /* init node's zones as empty zones, we don't have any present pages.*/ |
498 | free_area_init_node(nid, zones_size, start_pfn, zholes_size); |
499 | |
500 | return pgdat; |
501 | } |
502 | |
503 | static void rollback_node_hotadd(int nid, pg_data_t *pgdat) |
504 | { |
505 | arch_refresh_nodedata(nid, NULL); |
506 | arch_free_nodedata(pgdat); |
507 | return; |
508 | } |
509 | |
510 | |
511 | /* |
512 | * called by cpu_up() to online a node without onlined memory. |
513 | */ |
514 | int mem_online_node(int nid) |
515 | { |
516 | pg_data_t *pgdat; |
517 | int ret; |
518 | |
519 | lock_memory_hotplug(); |
520 | pgdat = hotadd_new_pgdat(nid, 0); |
521 | if (pgdat) { |
522 | ret = -ENOMEM; |
523 | goto out; |
524 | } |
525 | node_set_online(nid); |
526 | ret = register_one_node(nid); |
527 | BUG_ON(ret); |
528 | |
529 | out: |
530 | unlock_memory_hotplug(); |
531 | return ret; |
532 | } |
533 | |
534 | /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ |
535 | int __ref add_memory(int nid, u64 start, u64 size) |
536 | { |
537 | pg_data_t *pgdat = NULL; |
538 | int new_pgdat = 0; |
539 | struct resource *res; |
540 | int ret; |
541 | |
542 | lock_memory_hotplug(); |
543 | |
544 | res = register_memory_resource(start, size); |
545 | ret = -EEXIST; |
546 | if (!res) |
547 | goto out; |
548 | |
549 | if (!node_online(nid)) { |
550 | pgdat = hotadd_new_pgdat(nid, start); |
551 | ret = -ENOMEM; |
552 | if (!pgdat) |
553 | goto out; |
554 | new_pgdat = 1; |
555 | } |
556 | |
557 | /* call arch's memory hotadd */ |
558 | ret = arch_add_memory(nid, start, size); |
559 | |
560 | if (ret < 0) |
561 | goto error; |
562 | |
563 | /* we online node here. we can't roll back from here. */ |
564 | node_set_online(nid); |
565 | |
566 | if (new_pgdat) { |
567 | ret = register_one_node(nid); |
568 | /* |
569 | * If sysfs file of new node can't create, cpu on the node |
570 | * can't be hot-added. There is no rollback way now. |
571 | * So, check by BUG_ON() to catch it reluctantly.. |
572 | */ |
573 | BUG_ON(ret); |
574 | } |
575 | |
576 | /* create new memmap entry */ |
577 | firmware_map_add_hotplug(start, start + size, "System RAM"); |
578 | |
579 | goto out; |
580 | |
581 | error: |
582 | /* rollback pgdat allocation and others */ |
583 | if (new_pgdat) |
584 | rollback_node_hotadd(nid, pgdat); |
585 | if (res) |
586 | release_memory_resource(res); |
587 | |
588 | out: |
589 | unlock_memory_hotplug(); |
590 | return ret; |
591 | } |
592 | EXPORT_SYMBOL_GPL(add_memory); |
593 | |
594 | #ifdef CONFIG_MEMORY_HOTREMOVE |
595 | /* |
596 | * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy |
597 | * set and the size of the free page is given by page_order(). Using this, |
598 | * the function determines if the pageblock contains only free pages. |
599 | * Due to buddy contraints, a free page at least the size of a pageblock will |
600 | * be located at the start of the pageblock |
601 | */ |
602 | static inline int pageblock_free(struct page *page) |
603 | { |
604 | return PageBuddy(page) && page_order(page) >= pageblock_order; |
605 | } |
606 | |
607 | /* Return the start of the next active pageblock after a given page */ |
608 | static struct page *next_active_pageblock(struct page *page) |
609 | { |
610 | /* Ensure the starting page is pageblock-aligned */ |
611 | BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1)); |
612 | |
613 | /* If the entire pageblock is free, move to the end of free page */ |
614 | if (pageblock_free(page)) { |
615 | int order; |
616 | /* be careful. we don't have locks, page_order can be changed.*/ |
617 | order = page_order(page); |
618 | if ((order < MAX_ORDER) && (order >= pageblock_order)) |
619 | return page + (1 << order); |
620 | } |
621 | |
622 | return page + pageblock_nr_pages; |
623 | } |
624 | |
625 | /* Checks if this range of memory is likely to be hot-removable. */ |
626 | int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) |
627 | { |
628 | struct page *page = pfn_to_page(start_pfn); |
629 | struct page *end_page = page + nr_pages; |
630 | |
631 | /* Check the starting page of each pageblock within the range */ |
632 | for (; page < end_page; page = next_active_pageblock(page)) { |
633 | if (!is_pageblock_removable_nolock(page)) |
634 | return 0; |
635 | cond_resched(); |
636 | } |
637 | |
638 | /* All pageblocks in the memory block are likely to be hot-removable */ |
639 | return 1; |
640 | } |
641 | |
642 | /* |
643 | * Confirm all pages in a range [start, end) is belongs to the same zone. |
644 | */ |
645 | static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) |
646 | { |
647 | unsigned long pfn; |
648 | struct zone *zone = NULL; |
649 | struct page *page; |
650 | int i; |
651 | for (pfn = start_pfn; |
652 | pfn < end_pfn; |
653 | pfn += MAX_ORDER_NR_PAGES) { |
654 | i = 0; |
655 | /* This is just a CONFIG_HOLES_IN_ZONE check.*/ |
656 | while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) |
657 | i++; |
658 | if (i == MAX_ORDER_NR_PAGES) |
659 | continue; |
660 | page = pfn_to_page(pfn + i); |
661 | if (zone && page_zone(page) != zone) |
662 | return 0; |
663 | zone = page_zone(page); |
664 | } |
665 | return 1; |
666 | } |
667 | |
668 | /* |
669 | * Scanning pfn is much easier than scanning lru list. |
670 | * Scan pfn from start to end and Find LRU page. |
671 | */ |
672 | static unsigned long scan_lru_pages(unsigned long start, unsigned long end) |
673 | { |
674 | unsigned long pfn; |
675 | struct page *page; |
676 | for (pfn = start; pfn < end; pfn++) { |
677 | if (pfn_valid(pfn)) { |
678 | page = pfn_to_page(pfn); |
679 | if (PageLRU(page)) |
680 | return pfn; |
681 | } |
682 | } |
683 | return 0; |
684 | } |
685 | |
686 | static struct page * |
687 | hotremove_migrate_alloc(struct page *page, unsigned long private, int **x) |
688 | { |
689 | /* This should be improooooved!! */ |
690 | return alloc_page(GFP_HIGHUSER_MOVABLE); |
691 | } |
692 | |
693 | #define NR_OFFLINE_AT_ONCE_PAGES (256) |
694 | static int |
695 | do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) |
696 | { |
697 | unsigned long pfn; |
698 | struct page *page; |
699 | int move_pages = NR_OFFLINE_AT_ONCE_PAGES; |
700 | int not_managed = 0; |
701 | int ret = 0; |
702 | LIST_HEAD(source); |
703 | |
704 | for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { |
705 | if (!pfn_valid(pfn)) |
706 | continue; |
707 | page = pfn_to_page(pfn); |
708 | if (!page_count(page)) |
709 | continue; |
710 | /* |
711 | * We can skip free pages. And we can only deal with pages on |
712 | * LRU. |
713 | */ |
714 | ret = isolate_lru_page(page); |
715 | if (!ret) { /* Success */ |
716 | list_add_tail(&page->lru, &source); |
717 | move_pages--; |
718 | inc_zone_page_state(page, NR_ISOLATED_ANON + |
719 | page_is_file_cache(page)); |
720 | |
721 | } else { |
722 | #ifdef CONFIG_DEBUG_VM |
723 | printk(KERN_ALERT "removing pfn %lx from LRU failed\n", |
724 | pfn); |
725 | dump_page(page); |
726 | #endif |
727 | /* Becasue we don't have big zone->lock. we should |
728 | check this again here. */ |
729 | if (page_count(page)) { |
730 | not_managed++; |
731 | ret = -EBUSY; |
732 | break; |
733 | } |
734 | } |
735 | } |
736 | if (!list_empty(&source)) { |
737 | if (not_managed) { |
738 | putback_lru_pages(&source); |
739 | goto out; |
740 | } |
741 | /* this function returns # of failed pages */ |
742 | ret = migrate_pages(&source, hotremove_migrate_alloc, 0, |
743 | true, true); |
744 | if (ret) |
745 | putback_lru_pages(&source); |
746 | } |
747 | out: |
748 | return ret; |
749 | } |
750 | |
751 | /* |
752 | * remove from free_area[] and mark all as Reserved. |
753 | */ |
754 | static int |
755 | offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, |
756 | void *data) |
757 | { |
758 | __offline_isolated_pages(start, start + nr_pages); |
759 | return 0; |
760 | } |
761 | |
762 | static void |
763 | offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) |
764 | { |
765 | walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL, |
766 | offline_isolated_pages_cb); |
767 | } |
768 | |
769 | /* |
770 | * Check all pages in range, recoreded as memory resource, are isolated. |
771 | */ |
772 | static int |
773 | check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, |
774 | void *data) |
775 | { |
776 | int ret; |
777 | long offlined = *(long *)data; |
778 | ret = test_pages_isolated(start_pfn, start_pfn + nr_pages); |
779 | offlined = nr_pages; |
780 | if (!ret) |
781 | *(long *)data += offlined; |
782 | return ret; |
783 | } |
784 | |
785 | static long |
786 | check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) |
787 | { |
788 | long offlined = 0; |
789 | int ret; |
790 | |
791 | ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined, |
792 | check_pages_isolated_cb); |
793 | if (ret < 0) |
794 | offlined = (long)ret; |
795 | return offlined; |
796 | } |
797 | |
798 | static int offline_pages(unsigned long start_pfn, |
799 | unsigned long end_pfn, unsigned long timeout) |
800 | { |
801 | unsigned long pfn, nr_pages, expire; |
802 | long offlined_pages; |
803 | int ret, drain, retry_max, node; |
804 | struct zone *zone; |
805 | struct memory_notify arg; |
806 | |
807 | BUG_ON(start_pfn >= end_pfn); |
808 | /* at least, alignment against pageblock is necessary */ |
809 | if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) |
810 | return -EINVAL; |
811 | if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) |
812 | return -EINVAL; |
813 | /* This makes hotplug much easier...and readable. |
814 | we assume this for now. .*/ |
815 | if (!test_pages_in_a_zone(start_pfn, end_pfn)) |
816 | return -EINVAL; |
817 | |
818 | lock_memory_hotplug(); |
819 | |
820 | zone = page_zone(pfn_to_page(start_pfn)); |
821 | node = zone_to_nid(zone); |
822 | nr_pages = end_pfn - start_pfn; |
823 | |
824 | /* set above range as isolated */ |
825 | ret = start_isolate_page_range(start_pfn, end_pfn); |
826 | if (ret) |
827 | goto out; |
828 | |
829 | arg.start_pfn = start_pfn; |
830 | arg.nr_pages = nr_pages; |
831 | arg.status_change_nid = -1; |
832 | if (nr_pages >= node_present_pages(node)) |
833 | arg.status_change_nid = node; |
834 | |
835 | ret = memory_notify(MEM_GOING_OFFLINE, &arg); |
836 | ret = notifier_to_errno(ret); |
837 | if (ret) |
838 | goto failed_removal; |
839 | |
840 | pfn = start_pfn; |
841 | expire = jiffies + timeout; |
842 | drain = 0; |
843 | retry_max = 5; |
844 | repeat: |
845 | /* start memory hot removal */ |
846 | ret = -EAGAIN; |
847 | if (time_after(jiffies, expire)) |
848 | goto failed_removal; |
849 | ret = -EINTR; |
850 | if (signal_pending(current)) |
851 | goto failed_removal; |
852 | ret = 0; |
853 | if (drain) { |
854 | lru_add_drain_all(); |
855 | cond_resched(); |
856 | drain_all_pages(); |
857 | } |
858 | |
859 | pfn = scan_lru_pages(start_pfn, end_pfn); |
860 | if (pfn) { /* We have page on LRU */ |
861 | ret = do_migrate_range(pfn, end_pfn); |
862 | if (!ret) { |
863 | drain = 1; |
864 | goto repeat; |
865 | } else { |
866 | if (ret < 0) |
867 | if (--retry_max == 0) |
868 | goto failed_removal; |
869 | yield(); |
870 | drain = 1; |
871 | goto repeat; |
872 | } |
873 | } |
874 | /* drain all zone's lru pagevec, this is asyncronous... */ |
875 | lru_add_drain_all(); |
876 | yield(); |
877 | /* drain pcp pages , this is synchrouns. */ |
878 | drain_all_pages(); |
879 | /* check again */ |
880 | offlined_pages = check_pages_isolated(start_pfn, end_pfn); |
881 | if (offlined_pages < 0) { |
882 | ret = -EBUSY; |
883 | goto failed_removal; |
884 | } |
885 | printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); |
886 | /* Ok, all of our target is islaoted. |
887 | We cannot do rollback at this point. */ |
888 | offline_isolated_pages(start_pfn, end_pfn); |
889 | /* reset pagetype flags and makes migrate type to be MOVABLE */ |
890 | undo_isolate_page_range(start_pfn, end_pfn); |
891 | /* removal success */ |
892 | zone->present_pages -= offlined_pages; |
893 | zone->zone_pgdat->node_present_pages -= offlined_pages; |
894 | totalram_pages -= offlined_pages; |
895 | |
896 | setup_per_zone_wmarks(); |
897 | calculate_zone_inactive_ratio(zone); |
898 | if (!node_present_pages(node)) { |
899 | node_clear_state(node, N_HIGH_MEMORY); |
900 | kswapd_stop(node); |
901 | } |
902 | |
903 | vm_total_pages = nr_free_pagecache_pages(); |
904 | writeback_set_ratelimit(); |
905 | |
906 | memory_notify(MEM_OFFLINE, &arg); |
907 | unlock_memory_hotplug(); |
908 | return 0; |
909 | |
910 | failed_removal: |
911 | printk(KERN_INFO "memory offlining %lx to %lx failed\n", |
912 | start_pfn, end_pfn); |
913 | memory_notify(MEM_CANCEL_OFFLINE, &arg); |
914 | /* pushback to free area */ |
915 | undo_isolate_page_range(start_pfn, end_pfn); |
916 | |
917 | out: |
918 | unlock_memory_hotplug(); |
919 | return ret; |
920 | } |
921 | |
922 | int remove_memory(u64 start, u64 size) |
923 | { |
924 | unsigned long start_pfn, end_pfn; |
925 | |
926 | start_pfn = PFN_DOWN(start); |
927 | end_pfn = start_pfn + PFN_DOWN(size); |
928 | return offline_pages(start_pfn, end_pfn, 120 * HZ); |
929 | } |
930 | #else |
931 | int remove_memory(u64 start, u64 size) |
932 | { |
933 | return -EINVAL; |
934 | } |
935 | #endif /* CONFIG_MEMORY_HOTREMOVE */ |
936 | EXPORT_SYMBOL_GPL(remove_memory); |
937 |
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