2 * linux/mm/memory_hotplug.c
7 #include <linux/stddef.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>
30 #include <asm/tlbflush.h>
32 /* add this memory to iomem resource */
33 static struct resource *register_memory_resource(u64 start, u64 size)
36 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
39 res->name = "System RAM";
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);
52 static void release_memory_resource(struct resource *res)
56 release_resource(res);
62 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
63 static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
65 struct pglist_data *pgdat = zone->zone_pgdat;
66 int nr_pages = PAGES_PER_SECTION;
67 int nid = pgdat->node_id;
70 zone_type = zone - pgdat->node_zones;
71 if (!zone->wait_table) {
73 ret = init_currently_empty_zone(zone, phys_start_pfn,
74 nr_pages, MEMMAP_HOTPLUG);
78 memmap_init_zone(nr_pages, nid, zone_type,
79 phys_start_pfn, MEMMAP_HOTPLUG);
83 static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
85 int nr_pages = PAGES_PER_SECTION;
88 if (pfn_valid(phys_start_pfn))
91 ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
96 ret = __add_zone(zone, phys_start_pfn);
101 return register_new_memory(__pfn_to_section(phys_start_pfn));
104 static int __remove_section(struct zone *zone, struct mem_section *ms)
107 struct pglist_data *pgdat = zone->zone_pgdat;
110 if (!valid_section(ms))
113 ret = unregister_memory_section(ms);
117 pgdat_resize_lock(pgdat, &flags);
118 sparse_remove_one_section(zone, ms);
119 pgdat_resize_unlock(pgdat, &flags);
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
129 int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
130 unsigned long nr_pages)
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);
139 for (i = start_sec; i <= end_sec; i++) {
140 err = __add_section(zone, i << PFN_SECTION_SHIFT);
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.
147 if (err && (err != -EEXIST))
154 EXPORT_SYMBOL_GPL(__add_pages);
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)
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().
167 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
168 unsigned long nr_pages)
170 unsigned long i, ret = 0;
171 int sections_to_remove;
174 * We can only remove entire sections
176 BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
177 BUG_ON(nr_pages % PAGES_PER_SECTION);
179 release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
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));
190 EXPORT_SYMBOL_GPL(__remove_pages);
192 static void grow_zone_span(struct zone *zone,
193 unsigned long start_pfn, unsigned long end_pfn)
195 unsigned long old_zone_end_pfn;
197 zone_span_writelock(zone);
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;
203 zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
204 zone->zone_start_pfn;
206 zone_span_writeunlock(zone);
209 static void grow_pgdat_span(struct pglist_data *pgdat,
210 unsigned long start_pfn, unsigned long end_pfn)
212 unsigned long old_pgdat_end_pfn =
213 pgdat->node_start_pfn + pgdat->node_spanned_pages;
215 if (start_pfn < pgdat->node_start_pfn)
216 pgdat->node_start_pfn = start_pfn;
218 pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
219 pgdat->node_start_pfn;
222 static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
226 unsigned long onlined_pages = *(unsigned long *)arg;
228 if (PageReserved(pfn_to_page(start_pfn)))
229 for (i = 0; i < nr_pages; i++) {
230 page = pfn_to_page(start_pfn + i);
234 *(unsigned long *)arg = onlined_pages;
239 int online_pages(unsigned long pfn, unsigned long nr_pages)
242 unsigned long onlined_pages = 0;
244 int need_zonelists_rebuild = 0;
247 struct memory_notify arg;
250 arg.nr_pages = nr_pages;
251 arg.status_change_nid = -1;
253 nid = page_to_nid(pfn_to_page(pfn));
254 if (node_present_pages(nid) == 0)
255 arg.status_change_nid = nid;
257 ret = memory_notify(MEM_GOING_ONLINE, &arg);
258 ret = notifier_to_errno(ret);
260 memory_notify(MEM_CANCEL_ONLINE, &arg);
264 * This doesn't need a lock to do pfn_to_page().
265 * The section can't be removed here because of the
266 * memory_block->state_mutex.
268 zone = page_zone(pfn_to_page(pfn));
269 pgdat_resize_lock(zone->zone_pgdat, &flags);
270 grow_zone_span(zone, pfn, pfn + nr_pages);
271 grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages);
272 pgdat_resize_unlock(zone->zone_pgdat, &flags);
275 * If this zone is not populated, then it is not in zonelist.
276 * This means the page allocator ignores this zone.
277 * So, zonelist must be updated after online.
279 if (!populated_zone(zone))
280 need_zonelists_rebuild = 1;
282 walk_memory_resource(pfn, nr_pages, &onlined_pages,
284 zone->present_pages += onlined_pages;
285 zone->zone_pgdat->node_present_pages += onlined_pages;
287 setup_per_zone_pages_min();
289 kswapd_run(zone_to_nid(zone));
290 node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
293 if (need_zonelists_rebuild)
294 build_all_zonelists();
295 vm_total_pages = nr_free_pagecache_pages();
296 writeback_set_ratelimit();
299 memory_notify(MEM_ONLINE, &arg);
303 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
305 static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
307 struct pglist_data *pgdat;
308 unsigned long zones_size[MAX_NR_ZONES] = {0};
309 unsigned long zholes_size[MAX_NR_ZONES] = {0};
310 unsigned long start_pfn = start >> PAGE_SHIFT;
312 pgdat = arch_alloc_nodedata(nid);
316 arch_refresh_nodedata(nid, pgdat);
318 /* we can use NODE_DATA(nid) from here */
320 /* init node's zones as empty zones, we don't have any present pages.*/
321 free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
326 static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
328 arch_refresh_nodedata(nid, NULL);
329 arch_free_nodedata(pgdat);
334 int add_memory(int nid, u64 start, u64 size)
336 pg_data_t *pgdat = NULL;
338 struct resource *res;
341 res = register_memory_resource(start, size);
345 if (!node_online(nid)) {
346 pgdat = hotadd_new_pgdat(nid, start);
352 /* call arch's memory hotadd */
353 ret = arch_add_memory(nid, start, size);
358 /* we online node here. we can't roll back from here. */
359 node_set_online(nid);
361 cpuset_track_online_nodes();
364 ret = register_one_node(nid);
366 * If sysfs file of new node can't create, cpu on the node
367 * can't be hot-added. There is no rollback way now.
368 * So, check by BUG_ON() to catch it reluctantly..
375 /* rollback pgdat allocation and others */
377 rollback_node_hotadd(nid, pgdat);
379 release_memory_resource(res);
383 EXPORT_SYMBOL_GPL(add_memory);
385 #ifdef CONFIG_MEMORY_HOTREMOVE
387 * Confirm all pages in a range [start, end) is belongs to the same zone.
389 static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
392 struct zone *zone = NULL;
395 for (pfn = start_pfn;
397 pfn += MAX_ORDER_NR_PAGES) {
399 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
400 while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
402 if (i == MAX_ORDER_NR_PAGES)
404 page = pfn_to_page(pfn + i);
405 if (zone && page_zone(page) != zone)
407 zone = page_zone(page);
413 * Scanning pfn is much easier than scanning lru list.
414 * Scan pfn from start to end and Find LRU page.
416 int scan_lru_pages(unsigned long start, unsigned long end)
420 for (pfn = start; pfn < end; pfn++) {
421 if (pfn_valid(pfn)) {
422 page = pfn_to_page(pfn);
431 hotremove_migrate_alloc(struct page *page,
432 unsigned long private,
435 /* This should be improoooooved!! */
436 return alloc_page(GFP_HIGHUSER_PAGECACHE);
440 #define NR_OFFLINE_AT_ONCE_PAGES (256)
442 do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
446 int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
451 for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
454 page = pfn_to_page(pfn);
455 if (!page_count(page))
458 * We can skip free pages. And we can only deal with pages on
461 ret = isolate_lru_page(page, &source);
462 if (!ret) { /* Success */
465 /* Becasue we don't have big zone->lock. we should
466 check this again here. */
467 if (page_count(page))
469 #ifdef CONFIG_DEBUG_VM
470 printk(KERN_INFO "removing from LRU failed"
472 pfn, page_count(page), page->flags);
478 if (!list_empty(&source))
479 putback_lru_pages(&source);
483 if (list_empty(&source))
485 /* this function returns # of failed pages */
486 ret = migrate_pages(&source, hotremove_migrate_alloc, 0);
493 * remove from free_area[] and mark all as Reserved.
496 offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
499 __offline_isolated_pages(start, start + nr_pages);
504 offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
506 walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL,
507 offline_isolated_pages_cb);
511 * Check all pages in range, recoreded as memory resource, are isolated.
514 check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
518 long offlined = *(long *)data;
519 ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
522 *(long *)data += offlined;
527 check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
532 ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined,
533 check_pages_isolated_cb);
535 offlined = (long)ret;
539 int offline_pages(unsigned long start_pfn,
540 unsigned long end_pfn, unsigned long timeout)
542 unsigned long pfn, nr_pages, expire;
544 int ret, drain, retry_max, node;
546 struct memory_notify arg;
548 BUG_ON(start_pfn >= end_pfn);
549 /* at least, alignment against pageblock is necessary */
550 if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
552 if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
554 /* This makes hotplug much easier...and readable.
555 we assume this for now. .*/
556 if (!test_pages_in_a_zone(start_pfn, end_pfn))
559 zone = page_zone(pfn_to_page(start_pfn));
560 node = zone_to_nid(zone);
561 nr_pages = end_pfn - start_pfn;
563 /* set above range as isolated */
564 ret = start_isolate_page_range(start_pfn, end_pfn);
568 arg.start_pfn = start_pfn;
569 arg.nr_pages = nr_pages;
570 arg.status_change_nid = -1;
571 if (nr_pages >= node_present_pages(node))
572 arg.status_change_nid = node;
574 ret = memory_notify(MEM_GOING_OFFLINE, &arg);
575 ret = notifier_to_errno(ret);
580 expire = jiffies + timeout;
584 /* start memory hot removal */
586 if (time_after(jiffies, expire))
589 if (signal_pending(current))
594 flush_scheduled_work();
599 pfn = scan_lru_pages(start_pfn, end_pfn);
600 if (pfn) { /* We have page on LRU */
601 ret = do_migrate_range(pfn, end_pfn);
607 if (--retry_max == 0)
614 /* drain all zone's lru pagevec, this is asyncronous... */
616 flush_scheduled_work();
618 /* drain pcp pages , this is synchrouns. */
621 offlined_pages = check_pages_isolated(start_pfn, end_pfn);
622 if (offlined_pages < 0) {
626 printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
627 /* Ok, all of our target is islaoted.
628 We cannot do rollback at this point. */
629 offline_isolated_pages(start_pfn, end_pfn);
630 /* reset pagetype flags and makes migrate type to be MOVABLE */
631 undo_isolate_page_range(start_pfn, end_pfn);
632 /* removal success */
633 zone->present_pages -= offlined_pages;
634 zone->zone_pgdat->node_present_pages -= offlined_pages;
635 totalram_pages -= offlined_pages;
636 num_physpages -= offlined_pages;
638 vm_total_pages = nr_free_pagecache_pages();
639 writeback_set_ratelimit();
641 memory_notify(MEM_OFFLINE, &arg);
645 printk(KERN_INFO "memory offlining %lx to %lx failed\n",
647 memory_notify(MEM_CANCEL_OFFLINE, &arg);
648 /* pushback to free area */
649 undo_isolate_page_range(start_pfn, end_pfn);
654 int remove_memory(u64 start, u64 size)
658 EXPORT_SYMBOL_GPL(remove_memory);
659 #endif /* CONFIG_MEMORY_HOTREMOVE */