hotplug-memory: make online_page() common
[linux-2.6.git] / mm / memory_hotplug.c
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/cpuset.h>
26 #include <linux/delay.h>
27 #include <linux/migrate.h>
28 #include <linux/page-isolation.h>
29
30 #include <asm/tlbflush.h>
31
32 /* add this memory to iomem resource */
33 static struct resource *register_memory_resource(u64 start, u64 size)
34 {
35         struct resource *res;
36         res = kzalloc(sizeof(struct resource), GFP_KERNEL);
37         BUG_ON(!res);
38
39         res->name = "System RAM";
40         res->start = start;
41         res->end = start + size - 1;
42         res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
43         if (request_resource(&iomem_resource, res) < 0) {
44                 printk("System RAM resource %llx - %llx cannot be added\n",
45                 (unsigned long long)res->start, (unsigned long long)res->end);
46                 kfree(res);
47                 res = NULL;
48         }
49         return res;
50 }
51
52 static void release_memory_resource(struct resource *res)
53 {
54         if (!res)
55                 return;
56         release_resource(res);
57         kfree(res);
58         return;
59 }
60
61
62 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
63 static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
64 {
65         struct pglist_data *pgdat = zone->zone_pgdat;
66         int nr_pages = PAGES_PER_SECTION;
67         int nid = pgdat->node_id;
68         int zone_type;
69
70         zone_type = zone - pgdat->node_zones;
71         if (!zone->wait_table) {
72                 int ret = 0;
73                 ret = init_currently_empty_zone(zone, phys_start_pfn,
74                                                 nr_pages, MEMMAP_HOTPLUG);
75                 if (ret < 0)
76                         return ret;
77         }
78         memmap_init_zone(nr_pages, nid, zone_type,
79                          phys_start_pfn, MEMMAP_HOTPLUG);
80         return 0;
81 }
82
83 static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
84 {
85         int nr_pages = PAGES_PER_SECTION;
86         int ret;
87
88         if (pfn_valid(phys_start_pfn))
89                 return -EEXIST;
90
91         ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
92
93         if (ret < 0)
94                 return ret;
95
96         ret = __add_zone(zone, phys_start_pfn);
97
98         if (ret < 0)
99                 return ret;
100
101         return register_new_memory(__pfn_to_section(phys_start_pfn));
102 }
103
104 static int __remove_section(struct zone *zone, struct mem_section *ms)
105 {
106         unsigned long flags;
107         struct pglist_data *pgdat = zone->zone_pgdat;
108         int ret = -EINVAL;
109
110         if (!valid_section(ms))
111                 return ret;
112
113         ret = unregister_memory_section(ms);
114         if (ret)
115                 return ret;
116
117         pgdat_resize_lock(pgdat, &flags);
118         sparse_remove_one_section(zone, ms);
119         pgdat_resize_unlock(pgdat, &flags);
120         return 0;
121 }
122
123 /*
124  * Reasonably generic function for adding memory.  It is
125  * expected that archs that support memory hotplug will
126  * call this function after deciding the zone to which to
127  * add the new pages.
128  */
129 int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
130                  unsigned long nr_pages)
131 {
132         unsigned long i;
133         int err = 0;
134         int start_sec, end_sec;
135         /* during initialize mem_map, align hot-added range to section */
136         start_sec = pfn_to_section_nr(phys_start_pfn);
137         end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
138
139         for (i = start_sec; i <= end_sec; i++) {
140                 err = __add_section(zone, i << PFN_SECTION_SHIFT);
141
142                 /*
143                  * EEXIST is finally dealt with by ioresource collision
144                  * check. see add_memory() => register_memory_resource()
145                  * Warning will be printed if there is collision.
146                  */
147                 if (err && (err != -EEXIST))
148                         break;
149                 err = 0;
150         }
151
152         return err;
153 }
154 EXPORT_SYMBOL_GPL(__add_pages);
155
156 /**
157  * __remove_pages() - remove sections of pages from a zone
158  * @zone: zone from which pages need to be removed
159  * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
160  * @nr_pages: number of pages to remove (must be multiple of section size)
161  *
162  * Generic helper function to remove section mappings and sysfs entries
163  * for the section of the memory we are removing. Caller needs to make
164  * sure that pages are marked reserved and zones are adjust properly by
165  * calling offline_pages().
166  */
167 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
168                  unsigned long nr_pages)
169 {
170         unsigned long i, ret = 0;
171         int sections_to_remove;
172
173         /*
174          * We can only remove entire sections
175          */
176         BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
177         BUG_ON(nr_pages % PAGES_PER_SECTION);
178
179         release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
180
181         sections_to_remove = nr_pages / PAGES_PER_SECTION;
182         for (i = 0; i < sections_to_remove; i++) {
183                 unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
184                 ret = __remove_section(zone, __pfn_to_section(pfn));
185                 if (ret)
186                         break;
187         }
188         return ret;
189 }
190 EXPORT_SYMBOL_GPL(__remove_pages);
191
192 static void grow_zone_span(struct zone *zone,
193                 unsigned long start_pfn, unsigned long end_pfn)
194 {
195         unsigned long old_zone_end_pfn;
196
197         zone_span_writelock(zone);
198
199         old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
200         if (start_pfn < zone->zone_start_pfn)
201                 zone->zone_start_pfn = start_pfn;
202
203         zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
204                                 zone->zone_start_pfn;
205
206         zone_span_writeunlock(zone);
207 }
208
209 static void grow_pgdat_span(struct pglist_data *pgdat,
210                 unsigned long start_pfn, unsigned long end_pfn)
211 {
212         unsigned long old_pgdat_end_pfn =
213                 pgdat->node_start_pfn + pgdat->node_spanned_pages;
214
215         if (start_pfn < pgdat->node_start_pfn)
216                 pgdat->node_start_pfn = start_pfn;
217
218         pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
219                                         pgdat->node_start_pfn;
220 }
221
222 void online_page(struct page *page)
223 {
224         totalram_pages++;
225         num_physpages++;
226
227 #ifdef CONFIG_HIGHMEM
228         if (PageHighMem(page))
229                 totalhigh_pages++;
230 #endif
231
232 #ifdef CONFIG_FLATMEM
233         max_mapnr = max(page_to_pfn(page), max_mapnr);
234 #endif
235
236         ClearPageReserved(page);
237         init_page_count(page);
238         __free_page(page);
239 }
240
241 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
242                         void *arg)
243 {
244         unsigned long i;
245         unsigned long onlined_pages = *(unsigned long *)arg;
246         struct page *page;
247         if (PageReserved(pfn_to_page(start_pfn)))
248                 for (i = 0; i < nr_pages; i++) {
249                         page = pfn_to_page(start_pfn + i);
250                         online_page(page);
251                         onlined_pages++;
252                 }
253         *(unsigned long *)arg = onlined_pages;
254         return 0;
255 }
256
257
258 int online_pages(unsigned long pfn, unsigned long nr_pages)
259 {
260         unsigned long flags;
261         unsigned long onlined_pages = 0;
262         struct zone *zone;
263         int need_zonelists_rebuild = 0;
264         int nid;
265         int ret;
266         struct memory_notify arg;
267
268         arg.start_pfn = pfn;
269         arg.nr_pages = nr_pages;
270         arg.status_change_nid = -1;
271
272         nid = page_to_nid(pfn_to_page(pfn));
273         if (node_present_pages(nid) == 0)
274                 arg.status_change_nid = nid;
275
276         ret = memory_notify(MEM_GOING_ONLINE, &arg);
277         ret = notifier_to_errno(ret);
278         if (ret) {
279                 memory_notify(MEM_CANCEL_ONLINE, &arg);
280                 return ret;
281         }
282         /*
283          * This doesn't need a lock to do pfn_to_page().
284          * The section can't be removed here because of the
285          * memory_block->state_mutex.
286          */
287         zone = page_zone(pfn_to_page(pfn));
288         pgdat_resize_lock(zone->zone_pgdat, &flags);
289         grow_zone_span(zone, pfn, pfn + nr_pages);
290         grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages);
291         pgdat_resize_unlock(zone->zone_pgdat, &flags);
292
293         /*
294          * If this zone is not populated, then it is not in zonelist.
295          * This means the page allocator ignores this zone.
296          * So, zonelist must be updated after online.
297          */
298         if (!populated_zone(zone))
299                 need_zonelists_rebuild = 1;
300
301         walk_memory_resource(pfn, nr_pages, &onlined_pages,
302                 online_pages_range);
303         zone->present_pages += onlined_pages;
304         zone->zone_pgdat->node_present_pages += onlined_pages;
305
306         setup_per_zone_pages_min();
307         if (onlined_pages) {
308                 kswapd_run(zone_to_nid(zone));
309                 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
310         }
311
312         if (need_zonelists_rebuild)
313                 build_all_zonelists();
314         vm_total_pages = nr_free_pagecache_pages();
315         writeback_set_ratelimit();
316
317         if (onlined_pages)
318                 memory_notify(MEM_ONLINE, &arg);
319
320         return 0;
321 }
322 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
323
324 static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
325 {
326         struct pglist_data *pgdat;
327         unsigned long zones_size[MAX_NR_ZONES] = {0};
328         unsigned long zholes_size[MAX_NR_ZONES] = {0};
329         unsigned long start_pfn = start >> PAGE_SHIFT;
330
331         pgdat = arch_alloc_nodedata(nid);
332         if (!pgdat)
333                 return NULL;
334
335         arch_refresh_nodedata(nid, pgdat);
336
337         /* we can use NODE_DATA(nid) from here */
338
339         /* init node's zones as empty zones, we don't have any present pages.*/
340         free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
341
342         return pgdat;
343 }
344
345 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
346 {
347         arch_refresh_nodedata(nid, NULL);
348         arch_free_nodedata(pgdat);
349         return;
350 }
351
352
353 int add_memory(int nid, u64 start, u64 size)
354 {
355         pg_data_t *pgdat = NULL;
356         int new_pgdat = 0;
357         struct resource *res;
358         int ret;
359
360         res = register_memory_resource(start, size);
361         if (!res)
362                 return -EEXIST;
363
364         if (!node_online(nid)) {
365                 pgdat = hotadd_new_pgdat(nid, start);
366                 if (!pgdat)
367                         return -ENOMEM;
368                 new_pgdat = 1;
369         }
370
371         /* call arch's memory hotadd */
372         ret = arch_add_memory(nid, start, size);
373
374         if (ret < 0)
375                 goto error;
376
377         /* we online node here. we can't roll back from here. */
378         node_set_online(nid);
379
380         cpuset_track_online_nodes();
381
382         if (new_pgdat) {
383                 ret = register_one_node(nid);
384                 /*
385                  * If sysfs file of new node can't create, cpu on the node
386                  * can't be hot-added. There is no rollback way now.
387                  * So, check by BUG_ON() to catch it reluctantly..
388                  */
389                 BUG_ON(ret);
390         }
391
392         return ret;
393 error:
394         /* rollback pgdat allocation and others */
395         if (new_pgdat)
396                 rollback_node_hotadd(nid, pgdat);
397         if (res)
398                 release_memory_resource(res);
399
400         return ret;
401 }
402 EXPORT_SYMBOL_GPL(add_memory);
403
404 #ifdef CONFIG_MEMORY_HOTREMOVE
405 /*
406  * Confirm all pages in a range [start, end) is belongs to the same zone.
407  */
408 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
409 {
410         unsigned long pfn;
411         struct zone *zone = NULL;
412         struct page *page;
413         int i;
414         for (pfn = start_pfn;
415              pfn < end_pfn;
416              pfn += MAX_ORDER_NR_PAGES) {
417                 i = 0;
418                 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
419                 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
420                         i++;
421                 if (i == MAX_ORDER_NR_PAGES)
422                         continue;
423                 page = pfn_to_page(pfn + i);
424                 if (zone && page_zone(page) != zone)
425                         return 0;
426                 zone = page_zone(page);
427         }
428         return 1;
429 }
430
431 /*
432  * Scanning pfn is much easier than scanning lru list.
433  * Scan pfn from start to end and Find LRU page.
434  */
435 int scan_lru_pages(unsigned long start, unsigned long end)
436 {
437         unsigned long pfn;
438         struct page *page;
439         for (pfn = start; pfn < end; pfn++) {
440                 if (pfn_valid(pfn)) {
441                         page = pfn_to_page(pfn);
442                         if (PageLRU(page))
443                                 return pfn;
444                 }
445         }
446         return 0;
447 }
448
449 static struct page *
450 hotremove_migrate_alloc(struct page *page,
451                         unsigned long private,
452                         int **x)
453 {
454         /* This should be improoooooved!! */
455         return alloc_page(GFP_HIGHUSER_PAGECACHE);
456 }
457
458
459 #define NR_OFFLINE_AT_ONCE_PAGES        (256)
460 static int
461 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
462 {
463         unsigned long pfn;
464         struct page *page;
465         int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
466         int not_managed = 0;
467         int ret = 0;
468         LIST_HEAD(source);
469
470         for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
471                 if (!pfn_valid(pfn))
472                         continue;
473                 page = pfn_to_page(pfn);
474                 if (!page_count(page))
475                         continue;
476                 /*
477                  * We can skip free pages. And we can only deal with pages on
478                  * LRU.
479                  */
480                 ret = isolate_lru_page(page, &source);
481                 if (!ret) { /* Success */
482                         move_pages--;
483                 } else {
484                         /* Becasue we don't have big zone->lock. we should
485                            check this again here. */
486                         if (page_count(page))
487                                 not_managed++;
488 #ifdef CONFIG_DEBUG_VM
489                         printk(KERN_INFO "removing from LRU failed"
490                                          " %lx/%d/%lx\n",
491                                 pfn, page_count(page), page->flags);
492 #endif
493                 }
494         }
495         ret = -EBUSY;
496         if (not_managed) {
497                 if (!list_empty(&source))
498                         putback_lru_pages(&source);
499                 goto out;
500         }
501         ret = 0;
502         if (list_empty(&source))
503                 goto out;
504         /* this function returns # of failed pages */
505         ret = migrate_pages(&source, hotremove_migrate_alloc, 0);
506
507 out:
508         return ret;
509 }
510
511 /*
512  * remove from free_area[] and mark all as Reserved.
513  */
514 static int
515 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
516                         void *data)
517 {
518         __offline_isolated_pages(start, start + nr_pages);
519         return 0;
520 }
521
522 static void
523 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
524 {
525         walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL,
526                                 offline_isolated_pages_cb);
527 }
528
529 /*
530  * Check all pages in range, recoreded as memory resource, are isolated.
531  */
532 static int
533 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
534                         void *data)
535 {
536         int ret;
537         long offlined = *(long *)data;
538         ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
539         offlined = nr_pages;
540         if (!ret)
541                 *(long *)data += offlined;
542         return ret;
543 }
544
545 static long
546 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
547 {
548         long offlined = 0;
549         int ret;
550
551         ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined,
552                         check_pages_isolated_cb);
553         if (ret < 0)
554                 offlined = (long)ret;
555         return offlined;
556 }
557
558 int offline_pages(unsigned long start_pfn,
559                   unsigned long end_pfn, unsigned long timeout)
560 {
561         unsigned long pfn, nr_pages, expire;
562         long offlined_pages;
563         int ret, drain, retry_max, node;
564         struct zone *zone;
565         struct memory_notify arg;
566
567         BUG_ON(start_pfn >= end_pfn);
568         /* at least, alignment against pageblock is necessary */
569         if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
570                 return -EINVAL;
571         if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
572                 return -EINVAL;
573         /* This makes hotplug much easier...and readable.
574            we assume this for now. .*/
575         if (!test_pages_in_a_zone(start_pfn, end_pfn))
576                 return -EINVAL;
577
578         zone = page_zone(pfn_to_page(start_pfn));
579         node = zone_to_nid(zone);
580         nr_pages = end_pfn - start_pfn;
581
582         /* set above range as isolated */
583         ret = start_isolate_page_range(start_pfn, end_pfn);
584         if (ret)
585                 return ret;
586
587         arg.start_pfn = start_pfn;
588         arg.nr_pages = nr_pages;
589         arg.status_change_nid = -1;
590         if (nr_pages >= node_present_pages(node))
591                 arg.status_change_nid = node;
592
593         ret = memory_notify(MEM_GOING_OFFLINE, &arg);
594         ret = notifier_to_errno(ret);
595         if (ret)
596                 goto failed_removal;
597
598         pfn = start_pfn;
599         expire = jiffies + timeout;
600         drain = 0;
601         retry_max = 5;
602 repeat:
603         /* start memory hot removal */
604         ret = -EAGAIN;
605         if (time_after(jiffies, expire))
606                 goto failed_removal;
607         ret = -EINTR;
608         if (signal_pending(current))
609                 goto failed_removal;
610         ret = 0;
611         if (drain) {
612                 lru_add_drain_all();
613                 flush_scheduled_work();
614                 cond_resched();
615                 drain_all_pages();
616         }
617
618         pfn = scan_lru_pages(start_pfn, end_pfn);
619         if (pfn) { /* We have page on LRU */
620                 ret = do_migrate_range(pfn, end_pfn);
621                 if (!ret) {
622                         drain = 1;
623                         goto repeat;
624                 } else {
625                         if (ret < 0)
626                                 if (--retry_max == 0)
627                                         goto failed_removal;
628                         yield();
629                         drain = 1;
630                         goto repeat;
631                 }
632         }
633         /* drain all zone's lru pagevec, this is asyncronous... */
634         lru_add_drain_all();
635         flush_scheduled_work();
636         yield();
637         /* drain pcp pages , this is synchrouns. */
638         drain_all_pages();
639         /* check again */
640         offlined_pages = check_pages_isolated(start_pfn, end_pfn);
641         if (offlined_pages < 0) {
642                 ret = -EBUSY;
643                 goto failed_removal;
644         }
645         printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
646         /* Ok, all of our target is islaoted.
647            We cannot do rollback at this point. */
648         offline_isolated_pages(start_pfn, end_pfn);
649         /* reset pagetype flags and makes migrate type to be MOVABLE */
650         undo_isolate_page_range(start_pfn, end_pfn);
651         /* removal success */
652         zone->present_pages -= offlined_pages;
653         zone->zone_pgdat->node_present_pages -= offlined_pages;
654         totalram_pages -= offlined_pages;
655         num_physpages -= offlined_pages;
656
657         vm_total_pages = nr_free_pagecache_pages();
658         writeback_set_ratelimit();
659
660         memory_notify(MEM_OFFLINE, &arg);
661         return 0;
662
663 failed_removal:
664         printk(KERN_INFO "memory offlining %lx to %lx failed\n",
665                 start_pfn, end_pfn);
666         memory_notify(MEM_CANCEL_OFFLINE, &arg);
667         /* pushback to free area */
668         undo_isolate_page_range(start_pfn, end_pfn);
669
670         return ret;
671 }
672 #else
673 int remove_memory(u64 start, u64 size)
674 {
675         return -EINVAL;
676 }
677 EXPORT_SYMBOL_GPL(remove_memory);
678 #endif /* CONFIG_MEMORY_HOTREMOVE */