path: root/mm/memory_hotplug.c (plain)
blob: b4c8d7b9ab820f61cf5d5c6080119cb90d2c9d94

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/compiler.h>
13	#include <linux/export.h>
14	#include <linux/pagevec.h>
15	#include <linux/writeback.h>
16	#include <linux/slab.h>
17	#include <linux/sysctl.h>
18	#include <linux/cpu.h>
19	#include <linux/memory.h>
20	#include <linux/memremap.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	#include <linux/stop_machine.h>
33	#include <linux/hugetlb.h>
34	#include <linux/memblock.h>
35	#include <linux/bootmem.h>
36	#include <linux/compaction.h>
37	#include <linux/rmap.h>
38
39	#include <asm/tlbflush.h>
40
41	#include "internal.h"
42
43	/*
44	* online_page_callback contains pointer to current page onlining function.
45	* Initially it is generic_online_page(). If it is required it could be
46	* changed by calling set_online_page_callback() for callback registration
47	* and restore_online_page_callback() for generic callback restore.
48	*/
49
50	static void generic_online_page(struct page *page);
51
52	static online_page_callback_t online_page_callback = generic_online_page;
53	static DEFINE_MUTEX(online_page_callback_lock);
54
55	/* The same as the cpu_hotplug lock, but for memory hotplug. */
56	static struct {
57	struct task_struct *active_writer;
58	struct mutex lock; /* Synchronizes accesses to refcount, */
59	/*
60	* Also blocks the new readers during
61	* an ongoing mem hotplug operation.
62	*/
63	int refcount;
64
65	#ifdef CONFIG_DEBUG_LOCK_ALLOC
66	struct lockdep_map dep_map;
67	#endif
68	} mem_hotplug = {
69	.active_writer = NULL,
70	.lock = __MUTEX_INITIALIZER(mem_hotplug.lock),
71	.refcount = 0,
72	#ifdef CONFIG_DEBUG_LOCK_ALLOC
73	.dep_map = {.name = "mem_hotplug.lock" },
74	#endif
75	};
76
77	/* Lockdep annotations for get/put_online_mems() and mem_hotplug_begin/end() */
78	#define memhp_lock_acquire_read() lock_map_acquire_read(&mem_hotplug.dep_map)
79	#define memhp_lock_acquire() lock_map_acquire(&mem_hotplug.dep_map)
80	#define memhp_lock_release() lock_map_release(&mem_hotplug.dep_map)
81
82	#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
83	bool memhp_auto_online;
84	#else
85	bool memhp_auto_online = true;
86	#endif
87	EXPORT_SYMBOL_GPL(memhp_auto_online);
88
89	static int __init setup_memhp_default_state(char *str)
90	{
91	if (!strcmp(str, "online"))
92	memhp_auto_online = true;
93	else if (!strcmp(str, "offline"))
94	memhp_auto_online = false;
95
96	return 1;
97	}
98	__setup("memhp_default_state=", setup_memhp_default_state);
99
100	void get_online_mems(void)
101	{
102	might_sleep();
103	if (mem_hotplug.active_writer == current)
104	return;
105	memhp_lock_acquire_read();
106	mutex_lock(&mem_hotplug.lock);
107	mem_hotplug.refcount++;
108	mutex_unlock(&mem_hotplug.lock);
109
110	}
111
112	void put_online_mems(void)
113	{
114	if (mem_hotplug.active_writer == current)
115	return;
116	mutex_lock(&mem_hotplug.lock);
117
118	if (WARN_ON(!mem_hotplug.refcount))
119	mem_hotplug.refcount++; /* try to fix things up */
120
121	if (!--mem_hotplug.refcount && unlikely(mem_hotplug.active_writer))
122	wake_up_process(mem_hotplug.active_writer);
123	mutex_unlock(&mem_hotplug.lock);
124	memhp_lock_release();
125
126	}
127
128	void mem_hotplug_begin(void)
129	{
130	mem_hotplug.active_writer = current;
131
132	memhp_lock_acquire();
133	for (;;) {
134	mutex_lock(&mem_hotplug.lock);
135	if (likely(!mem_hotplug.refcount))
136	break;
137	__set_current_state(TASK_UNINTERRUPTIBLE);
138	mutex_unlock(&mem_hotplug.lock);
139	schedule();
140	}
141	}
142
143	void mem_hotplug_done(void)
144	{
145	mem_hotplug.active_writer = NULL;
146	mutex_unlock(&mem_hotplug.lock);
147	memhp_lock_release();
148	}
149
150	/* add this memory to iomem resource */
151	static struct resource *register_memory_resource(u64 start, u64 size)
152	{
153	struct resource *res;
154	res = kzalloc(sizeof(struct resource), GFP_KERNEL);
155	if (!res)
156	return ERR_PTR(-ENOMEM);
157
158	res->name = "System RAM";
159	res->start = start;
160	res->end = start + size - 1;
161	res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
162	if (request_resource(&iomem_resource, res) < 0) {
163	pr_debug("System RAM resource %pR cannot be added\n", res);
164	kfree(res);
165	return ERR_PTR(-EEXIST);
166	}
167	return res;
168	}
169
170	static void release_memory_resource(struct resource *res)
171	{
172	if (!res)
173	return;
174	release_resource(res);
175	kfree(res);
176	return;
177	}
178
179	#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
180	void get_page_bootmem(unsigned long info, struct page *page,
181	unsigned long type)
182	{
183	page->freelist = (void *)type;
184	SetPagePrivate(page);
185	set_page_private(page, info);
186	page_ref_inc(page);
187	}
188
189	void put_page_bootmem(struct page *page)
190	{
191	unsigned long type;
192
193	type = (unsigned long) page->freelist;
194	BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE ||
195	type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE);
196
197	if (page_ref_dec_return(page) == 1) {
198	page->freelist = NULL;
199	ClearPagePrivate(page);
200	set_page_private(page, 0);
201	INIT_LIST_HEAD(&page->lru);
202	free_reserved_page(page);
203	}
204	}
205
206	#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
207	#ifndef CONFIG_SPARSEMEM_VMEMMAP
208	static void register_page_bootmem_info_section(unsigned long start_pfn)
209	{
210	unsigned long *usemap, mapsize, section_nr, i;
211	struct mem_section *ms;
212	struct page *page, *memmap;
213
214	section_nr = pfn_to_section_nr(start_pfn);
215	ms = __nr_to_section(section_nr);
216
217	/* Get section's memmap address */
218	memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
219
220	/*
221	* Get page for the memmap's phys address
222	* XXX: need more consideration for sparse_vmemmap...
223	*/
224	page = virt_to_page(memmap);
225	mapsize = sizeof(struct page) * PAGES_PER_SECTION;
226	mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT;
227
228	/* remember memmap's page */
229	for (i = 0; i < mapsize; i++, page++)
230	get_page_bootmem(section_nr, page, SECTION_INFO);
231
232	usemap = __nr_to_section(section_nr)->pageblock_flags;
233	page = virt_to_page(usemap);
234
235	mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
236
237	for (i = 0; i < mapsize; i++, page++)
238	get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
239
240	}
241	#else /* CONFIG_SPARSEMEM_VMEMMAP */
242	static void register_page_bootmem_info_section(unsigned long start_pfn)
243	{
244	unsigned long *usemap, mapsize, section_nr, i;
245	struct mem_section *ms;
246	struct page *page, *memmap;
247
248	if (!pfn_valid(start_pfn))
249	return;
250
251	section_nr = pfn_to_section_nr(start_pfn);
252	ms = __nr_to_section(section_nr);
253
254	memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
255
256	register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION);
257
258	usemap = __nr_to_section(section_nr)->pageblock_flags;
259	page = virt_to_page(usemap);
260
261	mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT;
262
263	for (i = 0; i < mapsize; i++, page++)
264	get_page_bootmem(section_nr, page, MIX_SECTION_INFO);
265	}
266	#endif /* !CONFIG_SPARSEMEM_VMEMMAP */
267
268	void __init register_page_bootmem_info_node(struct pglist_data *pgdat)
269	{
270	unsigned long i, pfn, end_pfn, nr_pages;
271	int node = pgdat->node_id;
272	struct page *page;
273
274	nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT;
275	page = virt_to_page(pgdat);
276
277	for (i = 0; i < nr_pages; i++, page++)
278	get_page_bootmem(node, page, NODE_INFO);
279
280	pfn = pgdat->node_start_pfn;
281	end_pfn = pgdat_end_pfn(pgdat);
282
283	/* register section info */
284	for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
285	/*
286	* Some platforms can assign the same pfn to multiple nodes - on
287	* node0 as well as nodeN. To avoid registering a pfn against
288	* multiple nodes we check that this pfn does not already
289	* reside in some other nodes.
290	*/
291	if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node))
292	register_page_bootmem_info_section(pfn);
293	}
294	}
295	#endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */
296
297	static void __meminit grow_zone_span(struct zone *zone, unsigned long start_pfn,
298	unsigned long end_pfn)
299	{
300	unsigned long old_zone_end_pfn;
301
302	zone_span_writelock(zone);
303
304	old_zone_end_pfn = zone_end_pfn(zone);
305	if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
306	zone->zone_start_pfn = start_pfn;
307
308	zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
309	zone->zone_start_pfn;
310
311	zone_span_writeunlock(zone);
312	}
313
314	static void resize_zone(struct zone *zone, unsigned long start_pfn,
315	unsigned long end_pfn)
316	{
317	zone_span_writelock(zone);
318
319	if (end_pfn - start_pfn) {
320	zone->zone_start_pfn = start_pfn;
321	zone->spanned_pages = end_pfn - start_pfn;
322	} else {
323	/*
324	* make it consist as free_area_init_core(),
325	* if spanned_pages = 0, then keep start_pfn = 0
326	*/
327	zone->zone_start_pfn = 0;
328	zone->spanned_pages = 0;
329	}
330
331	zone_span_writeunlock(zone);
332	}
333
334	static void fix_zone_id(struct zone *zone, unsigned long start_pfn,
335	unsigned long end_pfn)
336	{
337	enum zone_type zid = zone_idx(zone);
338	int nid = zone->zone_pgdat->node_id;
339	unsigned long pfn;
340
341	for (pfn = start_pfn; pfn < end_pfn; pfn++)
342	set_page_links(pfn_to_page(pfn), zid, nid, pfn);
343	}
344
345	/* Can fail with -ENOMEM from allocating a wait table with vmalloc() or
346	* alloc_bootmem_node_nopanic()/memblock_virt_alloc_node_nopanic() */
347	static int __ref ensure_zone_is_initialized(struct zone *zone,
348	unsigned long start_pfn, unsigned long num_pages)
349	{
350	if (!zone_is_initialized(zone))
351	return init_currently_empty_zone(zone, start_pfn, num_pages);
352
353	return 0;
354	}
355
356	static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2,
357	unsigned long start_pfn, unsigned long end_pfn)
358	{
359	int ret;
360	unsigned long flags;
361	unsigned long z1_start_pfn;
362
363	ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn);
364	if (ret)
365	return ret;
366
367	pgdat_resize_lock(z1->zone_pgdat, &flags);
368
369	/* can't move pfns which are higher than @z2 */
370	if (end_pfn > zone_end_pfn(z2))
371	goto out_fail;
372	/* the move out part must be at the left most of @z2 */
373	if (start_pfn > z2->zone_start_pfn)
374	goto out_fail;
375	/* must included/overlap */
376	if (end_pfn <= z2->zone_start_pfn)
377	goto out_fail;
378
379	/* use start_pfn for z1's start_pfn if z1 is empty */
380	if (!zone_is_empty(z1))
381	z1_start_pfn = z1->zone_start_pfn;
382	else
383	z1_start_pfn = start_pfn;
384
385	resize_zone(z1, z1_start_pfn, end_pfn);
386	resize_zone(z2, end_pfn, zone_end_pfn(z2));
387
388	pgdat_resize_unlock(z1->zone_pgdat, &flags);
389
390	fix_zone_id(z1, start_pfn, end_pfn);
391
392	return 0;
393	out_fail:
394	pgdat_resize_unlock(z1->zone_pgdat, &flags);
395	return -1;
396	}
397
398	static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2,
399	unsigned long start_pfn, unsigned long end_pfn)
400	{
401	int ret;
402	unsigned long flags;
403	unsigned long z2_end_pfn;
404
405	ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn);
406	if (ret)
407	return ret;
408
409	pgdat_resize_lock(z1->zone_pgdat, &flags);
410
411	/* can't move pfns which are lower than @z1 */
412	if (z1->zone_start_pfn > start_pfn)
413	goto out_fail;
414	/* the move out part mast at the right most of @z1 */
415	if (zone_end_pfn(z1) > end_pfn)
416	goto out_fail;
417	/* must included/overlap */
418	if (start_pfn >= zone_end_pfn(z1))
419	goto out_fail;
420
421	/* use end_pfn for z2's end_pfn if z2 is empty */
422	if (!zone_is_empty(z2))
423	z2_end_pfn = zone_end_pfn(z2);
424	else
425	z2_end_pfn = end_pfn;
426
427	resize_zone(z1, z1->zone_start_pfn, start_pfn);
428	resize_zone(z2, start_pfn, z2_end_pfn);
429
430	pgdat_resize_unlock(z1->zone_pgdat, &flags);
431
432	fix_zone_id(z2, start_pfn, end_pfn);
433
434	return 0;
435	out_fail:
436	pgdat_resize_unlock(z1->zone_pgdat, &flags);
437	return -1;
438	}
439
440	static struct zone * __meminit move_pfn_range(int zone_shift,
441	unsigned long start_pfn, unsigned long end_pfn)
442	{
443	struct zone *zone = page_zone(pfn_to_page(start_pfn));
444	int ret = 0;
445
446	if (zone_shift < 0)
447	ret = move_pfn_range_left(zone + zone_shift, zone,
448	start_pfn, end_pfn);
449	else if (zone_shift)
450	ret = move_pfn_range_right(zone, zone + zone_shift,
451	start_pfn, end_pfn);
452
453	if (ret)
454	return NULL;
455
456	return zone + zone_shift;
457	}
458
459	static void __meminit grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
460	unsigned long end_pfn)
461	{
462	unsigned long old_pgdat_end_pfn = pgdat_end_pfn(pgdat);
463
464	if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
465	pgdat->node_start_pfn = start_pfn;
466
467	pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
468	pgdat->node_start_pfn;
469	}
470
471	static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn)
472	{
473	struct pglist_data *pgdat = zone->zone_pgdat;
474	int nr_pages = PAGES_PER_SECTION;
475	int nid = pgdat->node_id;
476	int zone_type;
477	unsigned long flags, pfn;
478	int ret;
479
480	zone_type = zone - pgdat->node_zones;
481	ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages);
482	if (ret)
483	return ret;
484
485	pgdat_resize_lock(zone->zone_pgdat, &flags);
486	grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages);
487	grow_pgdat_span(zone->zone_pgdat, phys_start_pfn,
488	phys_start_pfn + nr_pages);
489	pgdat_resize_unlock(zone->zone_pgdat, &flags);
490	memmap_init_zone(nr_pages, nid, zone_type,
491	phys_start_pfn, MEMMAP_HOTPLUG);
492
493	/* online_page_range is called later and expects pages reserved */
494	for (pfn = phys_start_pfn; pfn < phys_start_pfn + nr_pages; pfn++) {
495	if (!pfn_valid(pfn))
496	continue;
497
498	SetPageReserved(pfn_to_page(pfn));
499	}
500	return 0;
501	}
502
503	static int __meminit __add_section(int nid, struct zone *zone,
504	unsigned long phys_start_pfn)
505	{
506	int ret;
507
508	if (pfn_valid(phys_start_pfn))
509	return -EEXIST;
510
511	ret = sparse_add_one_section(zone, phys_start_pfn);
512
513	if (ret < 0)
514	return ret;
515
516	ret = __add_zone(zone, phys_start_pfn);
517
518	if (ret < 0)
519	return ret;
520
521	return register_new_memory(nid, __pfn_to_section(phys_start_pfn));
522	}
523
524	/*
525	* Reasonably generic function for adding memory. It is
526	* expected that archs that support memory hotplug will
527	* call this function after deciding the zone to which to
528	* add the new pages.
529	*/
530	int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
531	unsigned long nr_pages)
532	{
533	unsigned long i;
534	int err = 0;
535	int start_sec, end_sec;
536	struct vmem_altmap *altmap;
537
538	clear_zone_contiguous(zone);
539
540	/* during initialize mem_map, align hot-added range to section */
541	start_sec = pfn_to_section_nr(phys_start_pfn);
542	end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
543
544	altmap = to_vmem_altmap((unsigned long) pfn_to_page(phys_start_pfn));
545	if (altmap) {
546	/*
547	* Validate altmap is within bounds of the total request
548	*/
549	if (altmap->base_pfn != phys_start_pfn
550	|| vmem_altmap_offset(altmap) > nr_pages) {
551	pr_warn_once("memory add fail, invalid altmap\n");
552	err = -EINVAL;
553	goto out;
554	}
555	altmap->alloc = 0;
556	}
557
558	for (i = start_sec; i <= end_sec; i++) {
559	err = __add_section(nid, zone, section_nr_to_pfn(i));
560
561	/*
562	* EEXIST is finally dealt with by ioresource collision
563	* check. see add_memory() => register_memory_resource()
564	* Warning will be printed if there is collision.
565	*/
566	if (err && (err != -EEXIST))
567	break;
568	err = 0;
569	}
570	vmemmap_populate_print_last();
571	out:
572	set_zone_contiguous(zone);
573	return err;
574	}
575	EXPORT_SYMBOL_GPL(__add_pages);
576
577	#ifdef CONFIG_MEMORY_HOTREMOVE
578	/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
579	static int find_smallest_section_pfn(int nid, struct zone *zone,
580	unsigned long start_pfn,
581	unsigned long end_pfn)
582	{
583	struct mem_section *ms;
584
585	for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) {
586	ms = __pfn_to_section(start_pfn);
587
588	if (unlikely(!valid_section(ms)))
589	continue;
590
591	if (unlikely(pfn_to_nid(start_pfn) != nid))
592	continue;
593
594	if (zone && zone != page_zone(pfn_to_page(start_pfn)))
595	continue;
596
597	return start_pfn;
598	}
599
600	return 0;
601	}
602
603	/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
604	static int find_biggest_section_pfn(int nid, struct zone *zone,
605	unsigned long start_pfn,
606	unsigned long end_pfn)
607	{
608	struct mem_section *ms;
609	unsigned long pfn;
610
611	/* pfn is the end pfn of a memory section. */
612	pfn = end_pfn - 1;
613	for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) {
614	ms = __pfn_to_section(pfn);
615
616	if (unlikely(!valid_section(ms)))
617	continue;
618
619	if (unlikely(pfn_to_nid(pfn) != nid))
620	continue;
621
622	if (zone && zone != page_zone(pfn_to_page(pfn)))
623	continue;
624
625	return pfn;
626	}
627
628	return 0;
629	}
630
631	static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
632	unsigned long end_pfn)
633	{
634	unsigned long zone_start_pfn = zone->zone_start_pfn;
635	unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
636	unsigned long zone_end_pfn = z;
637	unsigned long pfn;
638	struct mem_section *ms;
639	int nid = zone_to_nid(zone);
640
641	zone_span_writelock(zone);
642	if (zone_start_pfn == start_pfn) {
643	/*
644	* If the section is smallest section in the zone, it need
645	* shrink zone->zone_start_pfn and zone->zone_spanned_pages.
646	* In this case, we find second smallest valid mem_section
647	* for shrinking zone.
648	*/
649	pfn = find_smallest_section_pfn(nid, zone, end_pfn,
650	zone_end_pfn);
651	if (pfn) {
652	zone->zone_start_pfn = pfn;
653	zone->spanned_pages = zone_end_pfn - pfn;
654	}
655	} else if (zone_end_pfn == end_pfn) {
656	/*
657	* If the section is biggest section in the zone, it need
658	* shrink zone->spanned_pages.
659	* In this case, we find second biggest valid mem_section for
660	* shrinking zone.
661	*/
662	pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
663	start_pfn);
664	if (pfn)
665	zone->spanned_pages = pfn - zone_start_pfn + 1;
666	}
667
668	/*
669	* The section is not biggest or smallest mem_section in the zone, it
670	* only creates a hole in the zone. So in this case, we need not
671	* change the zone. But perhaps, the zone has only hole data. Thus
672	* it check the zone has only hole or not.
673	*/
674	pfn = zone_start_pfn;
675	for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
676	ms = __pfn_to_section(pfn);
677
678	if (unlikely(!valid_section(ms)))
679	continue;
680
681	if (page_zone(pfn_to_page(pfn)) != zone)
682	continue;
683
684	/* If the section is current section, it continues the loop */
685	if (start_pfn == pfn)
686	continue;
687
688	/* If we find valid section, we have nothing to do */
689	zone_span_writeunlock(zone);
690	return;
691	}
692
693	/* The zone has no valid section */
694	zone->zone_start_pfn = 0;
695	zone->spanned_pages = 0;
696	zone_span_writeunlock(zone);
697	}
698
699	static void shrink_pgdat_span(struct pglist_data *pgdat,
700	unsigned long start_pfn, unsigned long end_pfn)
701	{
702	unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
703	unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */
704	unsigned long pgdat_end_pfn = p;
705	unsigned long pfn;
706	struct mem_section *ms;
707	int nid = pgdat->node_id;
708
709	if (pgdat_start_pfn == start_pfn) {
710	/*
711	* If the section is smallest section in the pgdat, it need
712	* shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
713	* In this case, we find second smallest valid mem_section
714	* for shrinking zone.
715	*/
716	pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
717	pgdat_end_pfn);
718	if (pfn) {
719	pgdat->node_start_pfn = pfn;
720	pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
721	}
722	} else if (pgdat_end_pfn == end_pfn) {
723	/*
724	* If the section is biggest section in the pgdat, it need
725	* shrink pgdat->node_spanned_pages.
726	* In this case, we find second biggest valid mem_section for
727	* shrinking zone.
728	*/
729	pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
730	start_pfn);
731	if (pfn)
732	pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
733	}
734
735	/*
736	* If the section is not biggest or smallest mem_section in the pgdat,
737	* it only creates a hole in the pgdat. So in this case, we need not
738	* change the pgdat.
739	* But perhaps, the pgdat has only hole data. Thus it check the pgdat
740	* has only hole or not.
741	*/
742	pfn = pgdat_start_pfn;
743	for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
744	ms = __pfn_to_section(pfn);
745
746	if (unlikely(!valid_section(ms)))
747	continue;
748
749	if (pfn_to_nid(pfn) != nid)
750	continue;
751
752	/* If the section is current section, it continues the loop */
753	if (start_pfn == pfn)
754	continue;
755
756	/* If we find valid section, we have nothing to do */
757	return;
758	}
759
760	/* The pgdat has no valid section */
761	pgdat->node_start_pfn = 0;
762	pgdat->node_spanned_pages = 0;
763	}
764
765	static void __remove_zone(struct zone *zone, unsigned long start_pfn)
766	{
767	struct pglist_data *pgdat = zone->zone_pgdat;
768	int nr_pages = PAGES_PER_SECTION;
769	int zone_type;
770	unsigned long flags;
771
772	zone_type = zone - pgdat->node_zones;
773
774	pgdat_resize_lock(zone->zone_pgdat, &flags);
775	shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
776	shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
777	pgdat_resize_unlock(zone->zone_pgdat, &flags);
778	}
779
780	static int __remove_section(struct zone *zone, struct mem_section *ms,
781	unsigned long map_offset)
782	{
783	unsigned long start_pfn;
784	int scn_nr;
785	int ret = -EINVAL;
786
787	if (!valid_section(ms))
788	return ret;
789
790	ret = unregister_memory_section(ms);
791	if (ret)
792	return ret;
793
794	scn_nr = __section_nr(ms);
795	start_pfn = section_nr_to_pfn(scn_nr);
796	__remove_zone(zone, start_pfn);
797
798	sparse_remove_one_section(zone, ms, map_offset);
799	return 0;
800	}
801
802	/**
803	* __remove_pages() - remove sections of pages from a zone
804	* @zone: zone from which pages need to be removed
805	* @phys_start_pfn: starting pageframe (must be aligned to start of a section)
806	* @nr_pages: number of pages to remove (must be multiple of section size)
807	*
808	* Generic helper function to remove section mappings and sysfs entries
809	* for the section of the memory we are removing. Caller needs to make
810	* sure that pages are marked reserved and zones are adjust properly by
811	* calling offline_pages().
812	*/
813	int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
814	unsigned long nr_pages)
815	{
816	unsigned long i;
817	unsigned long map_offset = 0;
818	int sections_to_remove, ret = 0;
819
820	/* In the ZONE_DEVICE case device driver owns the memory region */
821	if (is_dev_zone(zone)) {
822	struct page *page = pfn_to_page(phys_start_pfn);
823	struct vmem_altmap *altmap;
824
825	altmap = to_vmem_altmap((unsigned long) page);
826	if (altmap)
827	map_offset = vmem_altmap_offset(altmap);
828	} else {
829	resource_size_t start, size;
830
831	start = phys_start_pfn << PAGE_SHIFT;
832	size = nr_pages * PAGE_SIZE;
833
834	ret = release_mem_region_adjustable(&iomem_resource, start,
835	size);
836	if (ret) {
837	resource_size_t endres = start + size - 1;
838
839	pr_warn("Unable to release resource <%pa-%pa> (%d)\n",
840	&start, &endres, ret);
841	}
842	}
843
844	clear_zone_contiguous(zone);
845
846	/*
847	* We can only remove entire sections
848	*/
849	BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
850	BUG_ON(nr_pages % PAGES_PER_SECTION);
851
852	sections_to_remove = nr_pages / PAGES_PER_SECTION;
853	for (i = 0; i < sections_to_remove; i++) {
854	unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION;
855
856	ret = __remove_section(zone, __pfn_to_section(pfn), map_offset);
857	map_offset = 0;
858	if (ret)
859	break;
860	}
861
862	set_zone_contiguous(zone);
863
864	return ret;
865	}
866	EXPORT_SYMBOL_GPL(__remove_pages);
867	#endif /* CONFIG_MEMORY_HOTREMOVE */
868
869	int set_online_page_callback(online_page_callback_t callback)
870	{
871	int rc = -EINVAL;
872
873	get_online_mems();
874	mutex_lock(&online_page_callback_lock);
875
876	if (online_page_callback == generic_online_page) {
877	online_page_callback = callback;
878	rc = 0;
879	}
880
881	mutex_unlock(&online_page_callback_lock);
882	put_online_mems();
883
884	return rc;
885	}
886	EXPORT_SYMBOL_GPL(set_online_page_callback);
887
888	int restore_online_page_callback(online_page_callback_t callback)
889	{
890	int rc = -EINVAL;
891
892	get_online_mems();
893	mutex_lock(&online_page_callback_lock);
894
895	if (online_page_callback == callback) {
896	online_page_callback = generic_online_page;
897	rc = 0;
898	}
899
900	mutex_unlock(&online_page_callback_lock);
901	put_online_mems();
902
903	return rc;
904	}
905	EXPORT_SYMBOL_GPL(restore_online_page_callback);
906
907	void __online_page_set_limits(struct page *page)
908	{
909	}
910	EXPORT_SYMBOL_GPL(__online_page_set_limits);
911
912	void __online_page_increment_counters(struct page *page)
913	{
914	adjust_managed_page_count(page, 1);
915	}
916	EXPORT_SYMBOL_GPL(__online_page_increment_counters);
917
918	void __online_page_free(struct page *page)
919	{
920	__free_reserved_page(page);
921	}
922	EXPORT_SYMBOL_GPL(__online_page_free);
923
924	static void generic_online_page(struct page *page)
925	{
926	__online_page_set_limits(page);
927	__online_page_increment_counters(page);
928	__online_page_free(page);
929	}
930
931	static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
932	void *arg)
933	{
934	unsigned long i;
935	unsigned long onlined_pages = *(unsigned long *)arg;
936	struct page *page;
937	if (PageReserved(pfn_to_page(start_pfn)))
938	for (i = 0; i < nr_pages; i++) {
939	page = pfn_to_page(start_pfn + i);
940	(*online_page_callback)(page);
941	onlined_pages++;
942	}
943	*(unsigned long *)arg = onlined_pages;
944	return 0;
945	}
946
947	#ifdef CONFIG_MOVABLE_NODE
948	/*
949	* When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have
950	* normal memory.
951	*/
952	static bool can_online_high_movable(struct zone *zone)
953	{
954	return true;
955	}
956	#else /* CONFIG_MOVABLE_NODE */
957	/* ensure every online node has NORMAL memory */
958	static bool can_online_high_movable(struct zone *zone)
959	{
960	return node_state(zone_to_nid(zone), N_NORMAL_MEMORY);
961	}
962	#endif /* CONFIG_MOVABLE_NODE */
963
964	/* check which state of node_states will be changed when online memory */
965	static void node_states_check_changes_online(unsigned long nr_pages,
966	struct zone *zone, struct memory_notify *arg)
967	{
968	int nid = zone_to_nid(zone);
969	enum zone_type zone_last = ZONE_NORMAL;
970
971	/*
972	* If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
973	* contains nodes which have zones of 0...ZONE_NORMAL,
974	* set zone_last to ZONE_NORMAL.
975	*
976	* If we don't have HIGHMEM nor movable node,
977	* node_states[N_NORMAL_MEMORY] contains nodes which have zones of
978	* 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
979	*/
980	if (N_MEMORY == N_NORMAL_MEMORY)
981	zone_last = ZONE_MOVABLE;
982
983	/*
984	* if the memory to be online is in a zone of 0...zone_last, and
985	* the zones of 0...zone_last don't have memory before online, we will
986	* need to set the node to node_states[N_NORMAL_MEMORY] after
987	* the memory is online.
988	*/
989	if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY))
990	arg->status_change_nid_normal = nid;
991	else
992	arg->status_change_nid_normal = -1;
993
994	#ifdef CONFIG_HIGHMEM
995	/*
996	* If we have movable node, node_states[N_HIGH_MEMORY]
997	* contains nodes which have zones of 0...ZONE_HIGHMEM,
998	* set zone_last to ZONE_HIGHMEM.
999	*
1000	* If we don't have movable node, node_states[N_NORMAL_MEMORY]
1001	* contains nodes which have zones of 0...ZONE_MOVABLE,
1002	* set zone_last to ZONE_MOVABLE.
1003	*/
1004	zone_last = ZONE_HIGHMEM;
1005	if (N_MEMORY == N_HIGH_MEMORY)
1006	zone_last = ZONE_MOVABLE;
1007
1008	if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY))
1009	arg->status_change_nid_high = nid;
1010	else
1011	arg->status_change_nid_high = -1;
1012	#else
1013	arg->status_change_nid_high = arg->status_change_nid_normal;
1014	#endif
1015
1016	/*
1017	* if the node don't have memory befor online, we will need to
1018	* set the node to node_states[N_MEMORY] after the memory
1019	* is online.
1020	*/
1021	if (!node_state(nid, N_MEMORY))
1022	arg->status_change_nid = nid;
1023	else
1024	arg->status_change_nid = -1;
1025	}
1026
1027	static void node_states_set_node(int node, struct memory_notify *arg)
1028	{
1029	if (arg->status_change_nid_normal >= 0)
1030	node_set_state(node, N_NORMAL_MEMORY);
1031
1032	if (arg->status_change_nid_high >= 0)
1033	node_set_state(node, N_HIGH_MEMORY);
1034
1035	node_set_state(node, N_MEMORY);
1036	}
1037
1038	bool zone_can_shift(unsigned long pfn, unsigned long nr_pages,
1039	enum zone_type target, int *zone_shift)
1040	{
1041	struct zone *zone = page_zone(pfn_to_page(pfn));
1042	enum zone_type idx = zone_idx(zone);
1043	int i;
1044
1045	*zone_shift = 0;
1046
1047	if (idx < target) {
1048	/* pages must be at end of current zone */
1049	if (pfn + nr_pages != zone_end_pfn(zone))
1050	return false;
1051
1052	/* no zones in use between current zone and target */
1053	for (i = idx + 1; i < target; i++)
1054	if (zone_is_initialized(zone - idx + i))
1055	return false;
1056	}
1057
1058	if (target < idx) {
1059	/* pages must be at beginning of current zone */
1060	if (pfn != zone->zone_start_pfn)
1061	return false;
1062
1063	/* no zones in use between current zone and target */
1064	for (i = target + 1; i < idx; i++)
1065	if (zone_is_initialized(zone - idx + i))
1066	return false;
1067	}
1068
1069	*zone_shift = target - idx;
1070	return true;
1071	}
1072
1073	/* Must be protected by mem_hotplug_begin() */
1074	int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
1075	{
1076	unsigned long flags;
1077	unsigned long onlined_pages = 0;
1078	struct zone *zone;
1079	int need_zonelists_rebuild = 0;
1080	int nid;
1081	int ret;
1082	struct memory_notify arg;
1083	int zone_shift = 0;
1084
1085	/*
1086	* This doesn't need a lock to do pfn_to_page().
1087	* The section can't be removed here because of the
1088	* memory_block->state_mutex.
1089	*/
1090	zone = page_zone(pfn_to_page(pfn));
1091
1092	if ((zone_idx(zone) > ZONE_NORMAL ||
1093	online_type == MMOP_ONLINE_MOVABLE) &&
1094	!can_online_high_movable(zone))
1095	return -EINVAL;
1096
1097	if (online_type == MMOP_ONLINE_KERNEL) {
1098	if (!zone_can_shift(pfn, nr_pages, ZONE_NORMAL, &zone_shift))
1099	return -EINVAL;
1100	} else if (online_type == MMOP_ONLINE_MOVABLE) {
1101	if (!zone_can_shift(pfn, nr_pages, ZONE_MOVABLE, &zone_shift))
1102	return -EINVAL;
1103	}
1104
1105	zone = move_pfn_range(zone_shift, pfn, pfn + nr_pages);
1106	if (!zone)
1107	return -EINVAL;
1108
1109	arg.start_pfn = pfn;
1110	arg.nr_pages = nr_pages;
1111	node_states_check_changes_online(nr_pages, zone, &arg);
1112
1113	nid = zone_to_nid(zone);
1114
1115	ret = memory_notify(MEM_GOING_ONLINE, &arg);
1116	ret = notifier_to_errno(ret);
1117	if (ret)
1118	goto failed_addition;
1119
1120	/*
1121	* If this zone is not populated, then it is not in zonelist.
1122	* This means the page allocator ignores this zone.
1123	* So, zonelist must be updated after online.
1124	*/
1125	mutex_lock(&zonelists_mutex);
1126	if (!populated_zone(zone)) {
1127	need_zonelists_rebuild = 1;
1128	build_all_zonelists(NULL, zone);
1129	}
1130
1131	ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
1132	online_pages_range);
1133	if (ret) {
1134	if (need_zonelists_rebuild)
1135	zone_pcp_reset(zone);
1136	mutex_unlock(&zonelists_mutex);
1137	goto failed_addition;
1138	}
1139
1140	zone->present_pages += onlined_pages;
1141
1142	pgdat_resize_lock(zone->zone_pgdat, &flags);
1143	zone->zone_pgdat->node_present_pages += onlined_pages;
1144	pgdat_resize_unlock(zone->zone_pgdat, &flags);
1145
1146	if (onlined_pages) {
1147	node_states_set_node(nid, &arg);
1148	if (need_zonelists_rebuild)
1149	build_all_zonelists(NULL, NULL);
1150	else
1151	zone_pcp_update(zone);
1152	}
1153
1154	mutex_unlock(&zonelists_mutex);
1155
1156	init_per_zone_wmark_min();
1157
1158	if (onlined_pages) {
1159	kswapd_run(nid);
1160	kcompactd_run(nid);
1161	}
1162
1163	vm_total_pages = nr_free_pagecache_pages();
1164
1165	writeback_set_ratelimit();
1166
1167	if (onlined_pages)
1168	memory_notify(MEM_ONLINE, &arg);
1169	return 0;
1170
1171	failed_addition:
1172	pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
1173	(unsigned long long) pfn << PAGE_SHIFT,
1174	(((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
1175	memory_notify(MEM_CANCEL_ONLINE, &arg);
1176	return ret;
1177	}
1178	#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
1179
1180	static void reset_node_present_pages(pg_data_t *pgdat)
1181	{
1182	struct zone *z;
1183
1184	for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++)
1185	z->present_pages = 0;
1186
1187	pgdat->node_present_pages = 0;
1188	}
1189
1190	/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1191	static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
1192	{
1193	struct pglist_data *pgdat;
1194	unsigned long zones_size[MAX_NR_ZONES] = {0};
1195	unsigned long zholes_size[MAX_NR_ZONES] = {0};
1196	unsigned long start_pfn = PFN_DOWN(start);
1197
1198	pgdat = NODE_DATA(nid);
1199	if (!pgdat) {
1200	pgdat = arch_alloc_nodedata(nid);
1201	if (!pgdat)
1202	return NULL;
1203
1204	arch_refresh_nodedata(nid, pgdat);
1205	} else {
1206	/* Reset the nr_zones, order and classzone_idx before reuse */
1207	pgdat->nr_zones = 0;
1208	pgdat->kswapd_order = 0;
1209	pgdat->kswapd_classzone_idx = 0;
1210	}
1211
1212	/* we can use NODE_DATA(nid) from here */
1213
1214	/* init node's zones as empty zones, we don't have any present pages.*/
1215	free_area_init_node(nid, zones_size, start_pfn, zholes_size);
1216	pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
1217
1218	/*
1219	* The node we allocated has no zone fallback lists. For avoiding
1220	* to access not-initialized zonelist, build here.
1221	*/
1222	mutex_lock(&zonelists_mutex);
1223	build_all_zonelists(pgdat, NULL);
1224	mutex_unlock(&zonelists_mutex);
1225
1226	/*
1227	* zone->managed_pages is set to an approximate value in
1228	* free_area_init_core(), which will cause
1229	* /sys/device/system/node/nodeX/meminfo has wrong data.
1230	* So reset it to 0 before any memory is onlined.
1231	*/
1232	reset_node_managed_pages(pgdat);
1233
1234	/*
1235	* When memory is hot-added, all the memory is in offline state. So
1236	* clear all zones' present_pages because they will be updated in
1237	* online_pages() and offline_pages().
1238	*/
1239	reset_node_present_pages(pgdat);
1240
1241	return pgdat;
1242	}
1243
1244	static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
1245	{
1246	arch_refresh_nodedata(nid, NULL);
1247	free_percpu(pgdat->per_cpu_nodestats);
1248	arch_free_nodedata(pgdat);
1249	return;
1250	}
1251
1252
1253	/**
1254	* try_online_node - online a node if offlined
1255	*
1256	* called by cpu_up() to online a node without onlined memory.
1257	*/
1258	int try_online_node(int nid)
1259	{
1260	pg_data_t *pgdat;
1261	int ret;
1262
1263	if (node_online(nid))
1264	return 0;
1265
1266	mem_hotplug_begin();
1267	pgdat = hotadd_new_pgdat(nid, 0);
1268	if (!pgdat) {
1269	pr_err("Cannot online node %d due to NULL pgdat\n", nid);
1270	ret = -ENOMEM;
1271	goto out;
1272	}
1273	node_set_online(nid);
1274	ret = register_one_node(nid);
1275	BUG_ON(ret);
1276
1277	if (pgdat->node_zonelists->_zonerefs->zone == NULL) {
1278	mutex_lock(&zonelists_mutex);
1279	build_all_zonelists(NULL, NULL);
1280	mutex_unlock(&zonelists_mutex);
1281	}
1282
1283	out:
1284	mem_hotplug_done();
1285	return ret;
1286	}
1287
1288	static int check_hotplug_memory_range(u64 start, u64 size)
1289	{
1290	u64 start_pfn = PFN_DOWN(start);
1291	u64 nr_pages = size >> PAGE_SHIFT;
1292
1293	/* Memory range must be aligned with section */
1294	if ((start_pfn & ~PAGE_SECTION_MASK) ||
1295	(nr_pages % PAGES_PER_SECTION) || (!nr_pages)) {
1296	pr_err("Section-unaligned hotplug range: start 0x%llx, size 0x%llx\n",
1297	(unsigned long long)start,
1298	(unsigned long long)size);
1299	return -EINVAL;
1300	}
1301
1302	return 0;
1303	}
1304
1305	/*
1306	* If movable zone has already been setup, newly added memory should be check.
1307	* If its address is higher than movable zone, it should be added as movable.
1308	* Without this check, movable zone may overlap with other zone.
1309	*/
1310	static int should_add_memory_movable(int nid, u64 start, u64 size)
1311	{
1312	unsigned long start_pfn = start >> PAGE_SHIFT;
1313	pg_data_t *pgdat = NODE_DATA(nid);
1314	struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE;
1315
1316	if (zone_is_empty(movable_zone))
1317	return 0;
1318
1319	if (movable_zone->zone_start_pfn <= start_pfn)
1320	return 1;
1321
1322	return 0;
1323	}
1324
1325	int zone_for_memory(int nid, u64 start, u64 size, int zone_default,
1326	bool for_device)
1327	{
1328	#ifdef CONFIG_ZONE_DEVICE
1329	if (for_device)
1330	return ZONE_DEVICE;
1331	#endif
1332	if (should_add_memory_movable(nid, start, size))
1333	return ZONE_MOVABLE;
1334
1335	return zone_default;
1336	}
1337
1338	static int online_memory_block(struct memory_block *mem, void *arg)
1339	{
1340	return memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
1341	}
1342
1343	/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1344	int __ref add_memory_resource(int nid, struct resource *res, bool online)
1345	{
1346	u64 start, size;
1347	pg_data_t *pgdat = NULL;
1348	bool new_pgdat;
1349	bool new_node;
1350	int ret;
1351
1352	start = res->start;
1353	size = resource_size(res);
1354
1355	ret = check_hotplug_memory_range(start, size);
1356	if (ret)
1357	return ret;
1358
1359	{ /* Stupid hack to suppress address-never-null warning */
1360	void *p = NODE_DATA(nid);
1361	new_pgdat = !p;
1362	}
1363
1364	mem_hotplug_begin();
1365
1366	/*
1367	* Add new range to memblock so that when hotadd_new_pgdat() is called
1368	* to allocate new pgdat, get_pfn_range_for_nid() will be able to find
1369	* this new range and calculate total pages correctly. The range will
1370	* be removed at hot-remove time.
1371	*/
1372	memblock_add_node(start, size, nid);
1373
1374	new_node = !node_online(nid);
1375	if (new_node) {
1376	pgdat = hotadd_new_pgdat(nid, start);
1377	ret = -ENOMEM;
1378	if (!pgdat)
1379	goto error;
1380	}
1381
1382	/* call arch's memory hotadd */
1383	ret = arch_add_memory(nid, start, size, false);
1384
1385	if (ret < 0)
1386	goto error;
1387
1388	/* we online node here. we can't roll back from here. */
1389	node_set_online(nid);
1390
1391	if (new_node) {
1392	ret = register_one_node(nid);
1393	/*
1394	* If sysfs file of new node can't create, cpu on the node
1395	* can't be hot-added. There is no rollback way now.
1396	* So, check by BUG_ON() to catch it reluctantly..
1397	*/
1398	BUG_ON(ret);
1399	}
1400
1401	/* create new memmap entry */
1402	firmware_map_add_hotplug(start, start + size, "System RAM");
1403
1404	/* online pages if requested */
1405	if (online)
1406	walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
1407	NULL, online_memory_block);
1408
1409	goto out;
1410
1411	error:
1412	/* rollback pgdat allocation and others */
1413	if (new_pgdat)
1414	rollback_node_hotadd(nid, pgdat);
1415	memblock_remove(start, size);
1416
1417	out:
1418	mem_hotplug_done();
1419	return ret;
1420	}
1421	EXPORT_SYMBOL_GPL(add_memory_resource);
1422
1423	int __ref add_memory(int nid, u64 start, u64 size)
1424	{
1425	struct resource *res;
1426	int ret;
1427
1428	res = register_memory_resource(start, size);
1429	if (IS_ERR(res))
1430	return PTR_ERR(res);
1431
1432	ret = add_memory_resource(nid, res, memhp_auto_online);
1433	if (ret < 0)
1434	release_memory_resource(res);
1435	return ret;
1436	}
1437	EXPORT_SYMBOL_GPL(add_memory);
1438
1439	#ifdef CONFIG_MEMORY_HOTREMOVE
1440	/*
1441	* A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
1442	* set and the size of the free page is given by page_order(). Using this,
1443	* the function determines if the pageblock contains only free pages.
1444	* Due to buddy contraints, a free page at least the size of a pageblock will
1445	* be located at the start of the pageblock
1446	*/
1447	static inline int pageblock_free(struct page *page)
1448	{
1449	return PageBuddy(page) && page_order(page) >= pageblock_order;
1450	}
1451
1452	/* Return the start of the next active pageblock after a given page */
1453	static struct page *next_active_pageblock(struct page *page)
1454	{
1455	/* Ensure the starting page is pageblock-aligned */
1456	BUG_ON(page_to_pfn(page) & (pageblock_nr_pages - 1));
1457
1458	/* If the entire pageblock is free, move to the end of free page */
1459	if (pageblock_free(page)) {
1460	int order;
1461	/* be careful. we don't have locks, page_order can be changed.*/
1462	order = page_order(page);
1463	if ((order < MAX_ORDER) && (order >= pageblock_order))
1464	return page + (1 << order);
1465	}
1466
1467	return page + pageblock_nr_pages;
1468	}
1469
1470	/* Checks if this range of memory is likely to be hot-removable. */
1471	bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
1472	{
1473	struct page *page = pfn_to_page(start_pfn);
1474	unsigned long end_pfn = min(start_pfn + nr_pages, zone_end_pfn(page_zone(page)));
1475	struct page *end_page = pfn_to_page(end_pfn);
1476
1477	/* Check the starting page of each pageblock within the range */
1478	for (; page < end_page; page = next_active_pageblock(page)) {
1479	if (!is_pageblock_removable_nolock(page))
1480	return false;
1481	cond_resched();
1482	}
1483
1484	/* All pageblocks in the memory block are likely to be hot-removable */
1485	return true;
1486	}
1487
1488	/*
1489	* Confirm all pages in a range [start, end) belong to the same zone.
1490	* When true, return its valid [start, end).
1491	*/
1492	int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
1493	unsigned long *valid_start, unsigned long *valid_end)
1494	{
1495	unsigned long pfn, sec_end_pfn;
1496	unsigned long start, end;
1497	struct zone *zone = NULL;
1498	struct page *page;
1499	int i;
1500	for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1);
1501	pfn < end_pfn;
1502	pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) {
1503	/* Make sure the memory section is present first */
1504	if (!present_section_nr(pfn_to_section_nr(pfn)))
1505	continue;
1506	for (; pfn < sec_end_pfn && pfn < end_pfn;
1507	pfn += MAX_ORDER_NR_PAGES) {
1508	i = 0;
1509	/* This is just a CONFIG_HOLES_IN_ZONE check.*/
1510	while ((i < MAX_ORDER_NR_PAGES) &&
1511	!pfn_valid_within(pfn + i))
1512	i++;
1513	if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn)
1514	continue;
1515	/* Check if we got outside of the zone */
1516	if (zone && !zone_spans_pfn(zone, pfn + i))
1517	return 0;
1518	page = pfn_to_page(pfn + i);
1519	if (zone && page_zone(page) != zone)
1520	return 0;
1521	if (!zone)
1522	start = pfn + i;
1523	zone = page_zone(page);
1524	end = pfn + MAX_ORDER_NR_PAGES;
1525	}
1526	}
1527
1528	if (zone) {
1529	*valid_start = start;
1530	*valid_end = min(end, end_pfn);
1531	return 1;
1532	} else {
1533	return 0;
1534	}
1535	}
1536
1537	/*
1538	* Scan pfn range [start,end) to find movable/migratable pages (LRU pages
1539	* and hugepages). We scan pfn because it's much easier than scanning over
1540	* linked list. This function returns the pfn of the first found movable
1541	* page if it's found, otherwise 0.
1542	*/
1543	static unsigned long scan_movable_pages(unsigned long start, unsigned long end)
1544	{
1545	unsigned long pfn;
1546	struct page *page;
1547	for (pfn = start; pfn < end; pfn++) {
1548	if (pfn_valid(pfn)) {
1549	page = pfn_to_page(pfn);
1550	if (PageLRU(page))
1551	return pfn;
1552	if (PageHuge(page)) {
1553	if (page_huge_active(page))
1554	return pfn;
1555	else
1556	pfn = round_up(pfn + 1,
1557	1 << compound_order(page)) - 1;
1558	}
1559	}
1560	}
1561	return 0;
1562	}
1563
1564	static struct page *new_node_page(struct page *page, unsigned long private,
1565	int **result)
1566	{
1567	gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;
1568	int nid = page_to_nid(page);
1569	nodemask_t nmask = node_states[N_MEMORY];
1570	struct page *new_page = NULL;
1571
1572	/*
1573	* TODO: allocate a destination hugepage from a nearest neighbor node,
1574	* accordance with memory policy of the user process if possible. For
1575	* now as a simple work-around, we use the next node for destination.
1576	*/
1577	if (PageHuge(page))
1578	return alloc_huge_page_node(page_hstate(compound_head(page)),
1579	next_node_in(nid, nmask));
1580
1581	node_clear(nid, nmask);
1582
1583	if (PageHighMem(page)
1584	|| (zone_idx(page_zone(page)) == ZONE_MOVABLE))
1585	gfp_mask |= __GFP_HIGHMEM;
1586
1587	if (!nodes_empty(nmask))
1588	new_page = __alloc_pages_nodemask(gfp_mask, 0,
1589	node_zonelist(nid, gfp_mask), &nmask);
1590	if (!new_page)
1591	new_page = __alloc_pages(gfp_mask, 0,
1592	node_zonelist(nid, gfp_mask));
1593
1594	return new_page;
1595	}
1596
1597	#define NR_OFFLINE_AT_ONCE_PAGES (256)
1598	static int
1599	do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
1600	{
1601	unsigned long pfn;
1602	struct page *page;
1603	int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
1604	int not_managed = 0;
1605	int ret = 0;
1606	LIST_HEAD(source);
1607
1608	for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
1609	if (!pfn_valid(pfn))
1610	continue;
1611	page = pfn_to_page(pfn);
1612
1613	if (PageHuge(page)) {
1614	struct page *head = compound_head(page);
1615	pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1;
1616	if (compound_order(head) > PFN_SECTION_SHIFT) {
1617	ret = -EBUSY;
1618	break;
1619	}
1620	if (isolate_huge_page(page, &source))
1621	move_pages -= 1 << compound_order(head);
1622	continue;
1623	}
1624
1625	/*
1626	* HWPoison pages have elevated reference counts so the migration would
1627	* fail on them. It also doesn't make any sense to migrate them in the
1628	* first place. Still try to unmap such a page in case it is still mapped
1629	* (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1630	* the unmap as the catch all safety net).
1631	*/
1632	if (PageHWPoison(page)) {
1633	if (WARN_ON(PageLRU(page)))
1634	isolate_lru_page(page);
1635	if (page_mapped(page))
1636	try_to_unmap(page, TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS);
1637	continue;
1638	}
1639
1640	if (!get_page_unless_zero(page))
1641	continue;
1642	/*
1643	* We can skip free pages. And we can only deal with pages on
1644	* LRU.
1645	*/
1646	ret = isolate_lru_page(page);
1647	if (!ret) { /* Success */
1648	put_page(page);
1649	list_add_tail(&page->lru, &source);
1650	move_pages--;
1651	inc_node_page_state(page, NR_ISOLATED_ANON +
1652	page_is_file_cache(page));
1653
1654	} else {
1655	#ifdef CONFIG_DEBUG_VM
1656	pr_alert("removing pfn %lx from LRU failed\n", pfn);
1657	dump_page(page, "failed to remove from LRU");
1658	#endif
1659	put_page(page);
1660	/* Because we don't have big zone->lock. we should
1661	check this again here. */
1662	if (page_count(page)) {
1663	not_managed++;
1664	ret = -EBUSY;
1665	break;
1666	}
1667	}
1668	}
1669	if (!list_empty(&source)) {
1670	if (not_managed) {
1671	putback_movable_pages(&source);
1672	goto out;
1673	}
1674
1675	/* Allocate a new page from the nearest neighbor node */
1676	ret = migrate_pages(&source, new_node_page, NULL, 0,
1677	MIGRATE_SYNC, MR_MEMORY_HOTPLUG);
1678	if (ret)
1679	putback_movable_pages(&source);
1680	}
1681	out:
1682	return ret;
1683	}
1684
1685	/*
1686	* remove from free_area[] and mark all as Reserved.
1687	*/
1688	static int
1689	offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
1690	void *data)
1691	{
1692	__offline_isolated_pages(start, start + nr_pages);
1693	return 0;
1694	}
1695
1696	static void
1697	offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
1698	{
1699	walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
1700	offline_isolated_pages_cb);
1701	}
1702
1703	/*
1704	* Check all pages in range, recoreded as memory resource, are isolated.
1705	*/
1706	static int
1707	check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
1708	void *data)
1709	{
1710	int ret;
1711	long offlined = *(long *)data;
1712	ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true);
1713	offlined = nr_pages;
1714	if (!ret)
1715	*(long *)data += offlined;
1716	return ret;
1717	}
1718
1719	static long
1720	check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
1721	{
1722	long offlined = 0;
1723	int ret;
1724
1725	ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
1726	check_pages_isolated_cb);
1727	if (ret < 0)
1728	offlined = (long)ret;
1729	return offlined;
1730	}
1731
1732	#ifdef CONFIG_MOVABLE_NODE
1733	/*
1734	* When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have
1735	* normal memory.
1736	*/
1737	static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1738	{
1739	return true;
1740	}
1741	#else /* CONFIG_MOVABLE_NODE */
1742	/* ensure the node has NORMAL memory if it is still online */
1743	static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
1744	{
1745	struct pglist_data *pgdat = zone->zone_pgdat;
1746	unsigned long present_pages = 0;
1747	enum zone_type zt;
1748
1749	for (zt = 0; zt <= ZONE_NORMAL; zt++)
1750	present_pages += pgdat->node_zones[zt].present_pages;
1751
1752	if (present_pages > nr_pages)
1753	return true;
1754
1755	present_pages = 0;
1756	for (; zt <= ZONE_MOVABLE; zt++)
1757	present_pages += pgdat->node_zones[zt].present_pages;
1758
1759	/*
1760	* we can't offline the last normal memory until all
1761	* higher memory is offlined.
1762	*/
1763	return present_pages == 0;
1764	}
1765	#endif /* CONFIG_MOVABLE_NODE */
1766
1767	static int __init cmdline_parse_movable_node(char *p)
1768	{
1769	#ifdef CONFIG_MOVABLE_NODE
1770	/*
1771	* Memory used by the kernel cannot be hot-removed because Linux
1772	* cannot migrate the kernel pages. When memory hotplug is
1773	* enabled, we should prevent memblock from allocating memory
1774	* for the kernel.
1775	*
1776	* ACPI SRAT records all hotpluggable memory ranges. But before
1777	* SRAT is parsed, we don't know about it.
1778	*
1779	* The kernel image is loaded into memory at very early time. We
1780	* cannot prevent this anyway. So on NUMA system, we set any
1781	* node the kernel resides in as un-hotpluggable.
1782	*
1783	* Since on modern servers, one node could have double-digit
1784	* gigabytes memory, we can assume the memory around the kernel
1785	* image is also un-hotpluggable. So before SRAT is parsed, just
1786	* allocate memory near the kernel image to try the best to keep
1787	* the kernel away from hotpluggable memory.
1788	*/
1789	memblock_set_bottom_up(true);
1790	movable_node_enabled = true;
1791	#else
1792	pr_warn("movable_node option not supported\n");
1793	#endif
1794	return 0;
1795	}
1796	early_param("movable_node", cmdline_parse_movable_node);
1797
1798	/* check which state of node_states will be changed when offline memory */
1799	static void node_states_check_changes_offline(unsigned long nr_pages,
1800	struct zone *zone, struct memory_notify *arg)
1801	{
1802	struct pglist_data *pgdat = zone->zone_pgdat;
1803	unsigned long present_pages = 0;
1804	enum zone_type zt, zone_last = ZONE_NORMAL;
1805
1806	/*
1807	* If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY]
1808	* contains nodes which have zones of 0...ZONE_NORMAL,
1809	* set zone_last to ZONE_NORMAL.
1810	*
1811	* If we don't have HIGHMEM nor movable node,
1812	* node_states[N_NORMAL_MEMORY] contains nodes which have zones of
1813	* 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE.
1814	*/
1815	if (N_MEMORY == N_NORMAL_MEMORY)
1816	zone_last = ZONE_MOVABLE;
1817
1818	/*
1819	* check whether node_states[N_NORMAL_MEMORY] will be changed.
1820	* If the memory to be offline is in a zone of 0...zone_last,
1821	* and it is the last present memory, 0...zone_last will
1822	* become empty after offline , thus we can determind we will
1823	* need to clear the node from node_states[N_NORMAL_MEMORY].
1824	*/
1825	for (zt = 0; zt <= zone_last; zt++)
1826	present_pages += pgdat->node_zones[zt].present_pages;
1827	if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1828	arg->status_change_nid_normal = zone_to_nid(zone);
1829	else
1830	arg->status_change_nid_normal = -1;
1831
1832	#ifdef CONFIG_HIGHMEM
1833	/*
1834	* If we have movable node, node_states[N_HIGH_MEMORY]
1835	* contains nodes which have zones of 0...ZONE_HIGHMEM,
1836	* set zone_last to ZONE_HIGHMEM.
1837	*
1838	* If we don't have movable node, node_states[N_NORMAL_MEMORY]
1839	* contains nodes which have zones of 0...ZONE_MOVABLE,
1840	* set zone_last to ZONE_MOVABLE.
1841	*/
1842	zone_last = ZONE_HIGHMEM;
1843	if (N_MEMORY == N_HIGH_MEMORY)
1844	zone_last = ZONE_MOVABLE;
1845
1846	for (; zt <= zone_last; zt++)
1847	present_pages += pgdat->node_zones[zt].present_pages;
1848	if (zone_idx(zone) <= zone_last && nr_pages >= present_pages)
1849	arg->status_change_nid_high = zone_to_nid(zone);
1850	else
1851	arg->status_change_nid_high = -1;
1852	#else
1853	arg->status_change_nid_high = arg->status_change_nid_normal;
1854	#endif
1855
1856	/*
1857	* node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE
1858	*/
1859	zone_last = ZONE_MOVABLE;
1860
1861	/*
1862	* check whether node_states[N_HIGH_MEMORY] will be changed
1863	* If we try to offline the last present @nr_pages from the node,
1864	* we can determind we will need to clear the node from
1865	* node_states[N_HIGH_MEMORY].
1866	*/
1867	for (; zt <= zone_last; zt++)
1868	present_pages += pgdat->node_zones[zt].present_pages;
1869	if (nr_pages >= present_pages)
1870	arg->status_change_nid = zone_to_nid(zone);
1871	else
1872	arg->status_change_nid = -1;
1873	}
1874
1875	static void node_states_clear_node(int node, struct memory_notify *arg)
1876	{
1877	if (arg->status_change_nid_normal >= 0)
1878	node_clear_state(node, N_NORMAL_MEMORY);
1879
1880	if ((N_MEMORY != N_NORMAL_MEMORY) &&
1881	(arg->status_change_nid_high >= 0))
1882	node_clear_state(node, N_HIGH_MEMORY);
1883
1884	if ((N_MEMORY != N_HIGH_MEMORY) &&
1885	(arg->status_change_nid >= 0))
1886	node_clear_state(node, N_MEMORY);
1887	}
1888
1889	static int __ref __offline_pages(unsigned long start_pfn,
1890	unsigned long end_pfn, unsigned long timeout)
1891	{
1892	unsigned long pfn, nr_pages, expire;
1893	long offlined_pages;
1894	int ret, drain, retry_max, node;
1895	unsigned long flags;
1896	unsigned long valid_start, valid_end;
1897	struct zone *zone;
1898	struct memory_notify arg;
1899
1900	/* at least, alignment against pageblock is necessary */
1901	if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
1902	return -EINVAL;
1903	if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
1904	return -EINVAL;
1905	/* This makes hotplug much easier...and readable.
1906	we assume this for now. .*/
1907	if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end))
1908	return -EINVAL;
1909
1910	zone = page_zone(pfn_to_page(valid_start));
1911	node = zone_to_nid(zone);
1912	nr_pages = end_pfn - start_pfn;
1913
1914	if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages))
1915	return -EINVAL;
1916
1917	/* set above range as isolated */
1918	ret = start_isolate_page_range(start_pfn, end_pfn,
1919	MIGRATE_MOVABLE, true);
1920	if (ret)
1921	return ret;
1922
1923	arg.start_pfn = start_pfn;
1924	arg.nr_pages = nr_pages;
1925	node_states_check_changes_offline(nr_pages, zone, &arg);
1926
1927	ret = memory_notify(MEM_GOING_OFFLINE, &arg);
1928	ret = notifier_to_errno(ret);
1929	if (ret)
1930	goto failed_removal;
1931
1932	pfn = start_pfn;
1933	expire = jiffies + timeout;
1934	drain = 0;
1935	retry_max = 5;
1936	repeat:
1937	/* start memory hot removal */
1938	ret = -EAGAIN;
1939	if (time_after(jiffies, expire))
1940	goto failed_removal;
1941	ret = -EINTR;
1942	if (signal_pending(current))
1943	goto failed_removal;
1944	ret = 0;
1945	if (drain) {
1946	lru_add_drain_all();
1947	cond_resched();
1948	drain_all_pages(zone);
1949	}
1950
1951	pfn = scan_movable_pages(start_pfn, end_pfn);
1952	if (pfn) { /* We have movable pages */
1953	ret = do_migrate_range(pfn, end_pfn);
1954	if (!ret) {
1955	drain = 1;
1956	goto repeat;
1957	} else {
1958	if (ret < 0)
1959	if (--retry_max == 0)
1960	goto failed_removal;
1961	yield();
1962	drain = 1;
1963	goto repeat;
1964	}
1965	}
1966	/* drain all zone's lru pagevec, this is asynchronous... */
1967	lru_add_drain_all();
1968	yield();
1969	/* drain pcp pages, this is synchronous. */
1970	drain_all_pages(zone);
1971	/*
1972	* dissolve free hugepages in the memory block before doing offlining
1973	* actually in order to make hugetlbfs's object counting consistent.
1974	*/
1975	ret = dissolve_free_huge_pages(start_pfn, end_pfn);
1976	if (ret)
1977	goto failed_removal;
1978	/* check again */
1979	offlined_pages = check_pages_isolated(start_pfn, end_pfn);
1980	if (offlined_pages < 0) {
1981	ret = -EBUSY;
1982	goto failed_removal;
1983	}
1984	pr_info("Offlined Pages %ld\n", offlined_pages);
1985	/* Ok, all of our target is isolated.
1986	We cannot do rollback at this point. */
1987	offline_isolated_pages(start_pfn, end_pfn);
1988	/* reset pagetype flags and makes migrate type to be MOVABLE */
1989	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
1990	/* removal success */
1991	adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages);
1992	zone->present_pages -= offlined_pages;
1993
1994	pgdat_resize_lock(zone->zone_pgdat, &flags);
1995	zone->zone_pgdat->node_present_pages -= offlined_pages;
1996	pgdat_resize_unlock(zone->zone_pgdat, &flags);
1997
1998	init_per_zone_wmark_min();
1999
2000	if (!populated_zone(zone)) {
2001	zone_pcp_reset(zone);
2002	mutex_lock(&zonelists_mutex);
2003	build_all_zonelists(NULL, NULL);
2004	mutex_unlock(&zonelists_mutex);
2005	} else
2006	zone_pcp_update(zone);
2007
2008	node_states_clear_node(node, &arg);
2009	if (arg.status_change_nid >= 0) {
2010	kswapd_stop(node);
2011	kcompactd_stop(node);
2012	}
2013
2014	vm_total_pages = nr_free_pagecache_pages();
2015	writeback_set_ratelimit();
2016
2017	memory_notify(MEM_OFFLINE, &arg);
2018	return 0;
2019
2020	failed_removal:
2021	pr_debug("memory offlining [mem %#010llx-%#010llx] failed\n",
2022	(unsigned long long) start_pfn << PAGE_SHIFT,
2023	((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
2024	memory_notify(MEM_CANCEL_OFFLINE, &arg);
2025	/* pushback to free area */
2026	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
2027	return ret;
2028	}
2029
2030	/* Must be protected by mem_hotplug_begin() */
2031	int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
2032	{
2033	return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ);
2034	}
2035	#endif /* CONFIG_MEMORY_HOTREMOVE */
2036
2037	/**
2038	* walk_memory_range - walks through all mem sections in [start_pfn, end_pfn)
2039	* @start_pfn: start pfn of the memory range
2040	* @end_pfn: end pfn of the memory range
2041	* @arg: argument passed to func
2042	* @func: callback for each memory section walked
2043	*
2044	* This function walks through all present mem sections in range
2045	* [start_pfn, end_pfn) and call func on each mem section.
2046	*
2047	* Returns the return value of func.
2048	*/
2049	int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
2050	void *arg, int (*func)(struct memory_block *, void *))
2051	{
2052	struct memory_block *mem = NULL;
2053	struct mem_section *section;
2054	unsigned long pfn, section_nr;
2055	int ret;
2056
2057	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
2058	section_nr = pfn_to_section_nr(pfn);
2059	if (!present_section_nr(section_nr))
2060	continue;
2061
2062	section = __nr_to_section(section_nr);
2063	/* same memblock? */
2064	if (mem)
2065	if ((section_nr >= mem->start_section_nr) &&
2066	(section_nr <= mem->end_section_nr))
2067	continue;
2068
2069	mem = find_memory_block_hinted(section, mem);
2070	if (!mem)
2071	continue;
2072
2073	ret = func(mem, arg);
2074	if (ret) {
2075	kobject_put(&mem->dev.kobj);
2076	return ret;
2077	}
2078	}
2079
2080	if (mem)
2081	kobject_put(&mem->dev.kobj);
2082
2083	return 0;
2084	}
2085
2086	#ifdef CONFIG_MEMORY_HOTREMOVE
2087	static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
2088	{
2089	int ret = !is_memblock_offlined(mem);
2090
2091	if (unlikely(ret)) {
2092	phys_addr_t beginpa, endpa;
2093
2094	beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
2095	endpa = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1;
2096	pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
2097	&beginpa, &endpa);
2098	}
2099
2100	return ret;
2101	}
2102
2103	static int check_cpu_on_node(pg_data_t *pgdat)
2104	{
2105	int cpu;
2106
2107	for_each_present_cpu(cpu) {
2108	if (cpu_to_node(cpu) == pgdat->node_id)
2109	/*
2110	* the cpu on this node isn't removed, and we can't
2111	* offline this node.
2112	*/
2113	return -EBUSY;
2114	}
2115
2116	return 0;
2117	}
2118
2119	static void unmap_cpu_on_node(pg_data_t *pgdat)
2120	{
2121	#ifdef CONFIG_ACPI_NUMA
2122	int cpu;
2123
2124	for_each_possible_cpu(cpu)
2125	if (cpu_to_node(cpu) == pgdat->node_id)
2126	numa_clear_node(cpu);
2127	#endif
2128	}
2129
2130	static int check_and_unmap_cpu_on_node(pg_data_t *pgdat)
2131	{
2132	int ret;
2133
2134	ret = check_cpu_on_node(pgdat);
2135	if (ret)
2136	return ret;
2137
2138	/*
2139	* the node will be offlined when we come here, so we can clear
2140	* the cpu_to_node() now.
2141	*/
2142
2143	unmap_cpu_on_node(pgdat);
2144	return 0;
2145	}
2146
2147	/**
2148	* try_offline_node
2149	*
2150	* Offline a node if all memory sections and cpus of the node are removed.
2151	*
2152	* NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2153	* and online/offline operations before this call.
2154	*/
2155	void try_offline_node(int nid)
2156	{
2157	pg_data_t *pgdat = NODE_DATA(nid);
2158	unsigned long start_pfn = pgdat->node_start_pfn;
2159	unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
2160	unsigned long pfn;
2161
2162	for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
2163	unsigned long section_nr = pfn_to_section_nr(pfn);
2164
2165	if (!present_section_nr(section_nr))
2166	continue;
2167
2168	if (pfn_to_nid(pfn) != nid)
2169	continue;
2170
2171	/*
2172	* some memory sections of this node are not removed, and we
2173	* can't offline node now.
2174	*/
2175	return;
2176	}
2177
2178	if (check_and_unmap_cpu_on_node(pgdat))
2179	return;
2180
2181	/*
2182	* all memory/cpu of this node are removed, we can offline this
2183	* node now.
2184	*/
2185	node_set_offline(nid);
2186	unregister_one_node(nid);
2187	}
2188	EXPORT_SYMBOL(try_offline_node);
2189
2190	/**
2191	* remove_memory
2192	*
2193	* NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2194	* and online/offline operations before this call, as required by
2195	* try_offline_node().
2196	*/
2197	void __ref remove_memory(int nid, u64 start, u64 size)
2198	{
2199	int ret;
2200
2201	BUG_ON(check_hotplug_memory_range(start, size));
2202
2203	mem_hotplug_begin();
2204
2205	/*
2206	* All memory blocks must be offlined before removing memory. Check
2207	* whether all memory blocks in question are offline and trigger a BUG()
2208	* if this is not the case.
2209	*/
2210	ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
2211	check_memblock_offlined_cb);
2212	if (ret)
2213	BUG();
2214
2215	/* remove memmap entry */
2216	firmware_map_remove(start, start + size, "System RAM");
2217	memblock_free(start, size);
2218	memblock_remove(start, size);
2219
2220	arch_remove_memory(start, size);
2221
2222	try_offline_node(nid);
2223
2224	mem_hotplug_done();
2225	}
2226	EXPORT_SYMBOL_GPL(remove_memory);
2227	#endif /* CONFIG_MEMORY_HOTREMOVE */
2228