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