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/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>
32 #include <asm/tlbflush.h>
36 /* add this memory to iomem resource */
37 static struct resource
*register_memory_resource(u64 start
, u64 size
)
40 res
= kzalloc(sizeof(struct resource
), GFP_KERNEL
);
43 res
->name
= "System RAM";
45 res
->end
= start
+ size
- 1;
46 res
->flags
= IORESOURCE_MEM
| IORESOURCE_BUSY
;
47 if (request_resource(&iomem_resource
, res
) < 0) {
48 printk("System RAM resource %llx - %llx cannot be added\n",
49 (unsigned long long)res
->start
, (unsigned long long)res
->end
);
56 static void release_memory_resource(struct resource
*res
)
60 release_resource(res
);
65 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
66 #ifndef CONFIG_SPARSEMEM_VMEMMAP
67 static void get_page_bootmem(unsigned long info
, struct page
*page
, int type
)
69 atomic_set(&page
->_mapcount
, type
);
71 set_page_private(page
, info
);
72 atomic_inc(&page
->_count
);
75 void put_page_bootmem(struct page
*page
)
79 type
= atomic_read(&page
->_mapcount
);
82 if (atomic_dec_return(&page
->_count
) == 1) {
83 ClearPagePrivate(page
);
84 set_page_private(page
, 0);
85 reset_page_mapcount(page
);
86 __free_pages_bootmem(page
, 0);
91 static void register_page_bootmem_info_section(unsigned long start_pfn
)
93 unsigned long *usemap
, mapsize
, section_nr
, i
;
94 struct mem_section
*ms
;
95 struct page
*page
, *memmap
;
97 if (!pfn_valid(start_pfn
))
100 section_nr
= pfn_to_section_nr(start_pfn
);
101 ms
= __nr_to_section(section_nr
);
103 /* Get section's memmap address */
104 memmap
= sparse_decode_mem_map(ms
->section_mem_map
, section_nr
);
107 * Get page for the memmap's phys address
108 * XXX: need more consideration for sparse_vmemmap...
110 page
= virt_to_page(memmap
);
111 mapsize
= sizeof(struct page
) * PAGES_PER_SECTION
;
112 mapsize
= PAGE_ALIGN(mapsize
) >> PAGE_SHIFT
;
114 /* remember memmap's page */
115 for (i
= 0; i
< mapsize
; i
++, page
++)
116 get_page_bootmem(section_nr
, page
, SECTION_INFO
);
118 usemap
= __nr_to_section(section_nr
)->pageblock_flags
;
119 page
= virt_to_page(usemap
);
121 mapsize
= PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT
;
123 for (i
= 0; i
< mapsize
; i
++, page
++)
124 get_page_bootmem(section_nr
, page
, MIX_SECTION_INFO
);
128 void register_page_bootmem_info_node(struct pglist_data
*pgdat
)
130 unsigned long i
, pfn
, end_pfn
, nr_pages
;
131 int node
= pgdat
->node_id
;
135 nr_pages
= PAGE_ALIGN(sizeof(struct pglist_data
)) >> PAGE_SHIFT
;
136 page
= virt_to_page(pgdat
);
138 for (i
= 0; i
< nr_pages
; i
++, page
++)
139 get_page_bootmem(node
, page
, NODE_INFO
);
141 zone
= &pgdat
->node_zones
[0];
142 for (; zone
< pgdat
->node_zones
+ MAX_NR_ZONES
- 1; zone
++) {
143 if (zone
->wait_table
) {
144 nr_pages
= zone
->wait_table_hash_nr_entries
145 * sizeof(wait_queue_head_t
);
146 nr_pages
= PAGE_ALIGN(nr_pages
) >> PAGE_SHIFT
;
147 page
= virt_to_page(zone
->wait_table
);
149 for (i
= 0; i
< nr_pages
; i
++, page
++)
150 get_page_bootmem(node
, page
, NODE_INFO
);
154 pfn
= pgdat
->node_start_pfn
;
155 end_pfn
= pfn
+ pgdat
->node_spanned_pages
;
157 /* register_section info */
158 for (; pfn
< end_pfn
; pfn
+= PAGES_PER_SECTION
)
159 register_page_bootmem_info_section(pfn
);
162 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
164 static void grow_zone_span(struct zone
*zone
, unsigned long start_pfn
,
165 unsigned long end_pfn
)
167 unsigned long old_zone_end_pfn
;
169 zone_span_writelock(zone
);
171 old_zone_end_pfn
= zone
->zone_start_pfn
+ zone
->spanned_pages
;
172 if (start_pfn
< zone
->zone_start_pfn
)
173 zone
->zone_start_pfn
= start_pfn
;
175 zone
->spanned_pages
= max(old_zone_end_pfn
, end_pfn
) -
176 zone
->zone_start_pfn
;
178 zone_span_writeunlock(zone
);
181 static void grow_pgdat_span(struct pglist_data
*pgdat
, unsigned long start_pfn
,
182 unsigned long end_pfn
)
184 unsigned long old_pgdat_end_pfn
=
185 pgdat
->node_start_pfn
+ pgdat
->node_spanned_pages
;
187 if (start_pfn
< pgdat
->node_start_pfn
)
188 pgdat
->node_start_pfn
= start_pfn
;
190 pgdat
->node_spanned_pages
= max(old_pgdat_end_pfn
, end_pfn
) -
191 pgdat
->node_start_pfn
;
194 static int __meminit
__add_zone(struct zone
*zone
, unsigned long phys_start_pfn
)
196 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
197 int nr_pages
= PAGES_PER_SECTION
;
198 int nid
= pgdat
->node_id
;
202 zone_type
= zone
- pgdat
->node_zones
;
203 if (!zone
->wait_table
) {
206 ret
= init_currently_empty_zone(zone
, phys_start_pfn
,
207 nr_pages
, MEMMAP_HOTPLUG
);
211 pgdat_resize_lock(zone
->zone_pgdat
, &flags
);
212 grow_zone_span(zone
, phys_start_pfn
, phys_start_pfn
+ nr_pages
);
213 grow_pgdat_span(zone
->zone_pgdat
, phys_start_pfn
,
214 phys_start_pfn
+ nr_pages
);
215 pgdat_resize_unlock(zone
->zone_pgdat
, &flags
);
216 memmap_init_zone(nr_pages
, nid
, zone_type
,
217 phys_start_pfn
, MEMMAP_HOTPLUG
);
221 static int __meminit
__add_section(int nid
, struct zone
*zone
,
222 unsigned long phys_start_pfn
)
224 int nr_pages
= PAGES_PER_SECTION
;
227 if (pfn_valid(phys_start_pfn
))
230 ret
= sparse_add_one_section(zone
, phys_start_pfn
, nr_pages
);
235 ret
= __add_zone(zone
, phys_start_pfn
);
240 return register_new_memory(nid
, __pfn_to_section(phys_start_pfn
));
243 #ifdef CONFIG_SPARSEMEM_VMEMMAP
244 static int __remove_section(struct zone
*zone
, struct mem_section
*ms
)
247 * XXX: Freeing memmap with vmemmap is not implement yet.
248 * This should be removed later.
253 static int __remove_section(struct zone
*zone
, struct mem_section
*ms
)
256 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
259 if (!valid_section(ms
))
262 ret
= unregister_memory_section(ms
);
266 pgdat_resize_lock(pgdat
, &flags
);
267 sparse_remove_one_section(zone
, ms
);
268 pgdat_resize_unlock(pgdat
, &flags
);
274 * Reasonably generic function for adding memory. It is
275 * expected that archs that support memory hotplug will
276 * call this function after deciding the zone to which to
279 int __ref
__add_pages(int nid
, struct zone
*zone
, unsigned long phys_start_pfn
,
280 unsigned long nr_pages
)
284 int start_sec
, end_sec
;
285 /* during initialize mem_map, align hot-added range to section */
286 start_sec
= pfn_to_section_nr(phys_start_pfn
);
287 end_sec
= pfn_to_section_nr(phys_start_pfn
+ nr_pages
- 1);
289 for (i
= start_sec
; i
<= end_sec
; i
++) {
290 err
= __add_section(nid
, zone
, i
<< PFN_SECTION_SHIFT
);
293 * EEXIST is finally dealt with by ioresource collision
294 * check. see add_memory() => register_memory_resource()
295 * Warning will be printed if there is collision.
297 if (err
&& (err
!= -EEXIST
))
304 EXPORT_SYMBOL_GPL(__add_pages
);
307 * __remove_pages() - remove sections of pages from a zone
308 * @zone: zone from which pages need to be removed
309 * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
310 * @nr_pages: number of pages to remove (must be multiple of section size)
312 * Generic helper function to remove section mappings and sysfs entries
313 * for the section of the memory we are removing. Caller needs to make
314 * sure that pages are marked reserved and zones are adjust properly by
315 * calling offline_pages().
317 int __remove_pages(struct zone
*zone
, unsigned long phys_start_pfn
,
318 unsigned long nr_pages
)
320 unsigned long i
, ret
= 0;
321 int sections_to_remove
;
324 * We can only remove entire sections
326 BUG_ON(phys_start_pfn
& ~PAGE_SECTION_MASK
);
327 BUG_ON(nr_pages
% PAGES_PER_SECTION
);
329 sections_to_remove
= nr_pages
/ PAGES_PER_SECTION
;
330 for (i
= 0; i
< sections_to_remove
; i
++) {
331 unsigned long pfn
= phys_start_pfn
+ i
*PAGES_PER_SECTION
;
332 release_mem_region(pfn
<< PAGE_SHIFT
,
333 PAGES_PER_SECTION
<< PAGE_SHIFT
);
334 ret
= __remove_section(zone
, __pfn_to_section(pfn
));
340 EXPORT_SYMBOL_GPL(__remove_pages
);
342 void online_page(struct page
*page
)
344 unsigned long pfn
= page_to_pfn(page
);
347 if (pfn
>= num_physpages
)
348 num_physpages
= pfn
+ 1;
350 #ifdef CONFIG_HIGHMEM
351 if (PageHighMem(page
))
355 #ifdef CONFIG_FLATMEM
356 max_mapnr
= max(page_to_pfn(page
), max_mapnr
);
359 ClearPageReserved(page
);
360 init_page_count(page
);
364 static int online_pages_range(unsigned long start_pfn
, unsigned long nr_pages
,
368 unsigned long onlined_pages
= *(unsigned long *)arg
;
370 if (PageReserved(pfn_to_page(start_pfn
)))
371 for (i
= 0; i
< nr_pages
; i
++) {
372 page
= pfn_to_page(start_pfn
+ i
);
376 *(unsigned long *)arg
= onlined_pages
;
381 int online_pages(unsigned long pfn
, unsigned long nr_pages
)
383 unsigned long onlined_pages
= 0;
385 int need_zonelists_rebuild
= 0;
388 struct memory_notify arg
;
391 arg
.nr_pages
= nr_pages
;
392 arg
.status_change_nid
= -1;
394 nid
= page_to_nid(pfn_to_page(pfn
));
395 if (node_present_pages(nid
) == 0)
396 arg
.status_change_nid
= nid
;
398 ret
= memory_notify(MEM_GOING_ONLINE
, &arg
);
399 ret
= notifier_to_errno(ret
);
401 memory_notify(MEM_CANCEL_ONLINE
, &arg
);
405 * This doesn't need a lock to do pfn_to_page().
406 * The section can't be removed here because of the
407 * memory_block->state_mutex.
409 zone
= page_zone(pfn_to_page(pfn
));
411 * If this zone is not populated, then it is not in zonelist.
412 * This means the page allocator ignores this zone.
413 * So, zonelist must be updated after online.
415 if (!populated_zone(zone
))
416 need_zonelists_rebuild
= 1;
418 ret
= walk_system_ram_range(pfn
, nr_pages
, &onlined_pages
,
421 printk(KERN_DEBUG
"online_pages %lx at %lx failed\n",
423 memory_notify(MEM_CANCEL_ONLINE
, &arg
);
427 zone
->present_pages
+= onlined_pages
;
428 zone
->zone_pgdat
->node_present_pages
+= onlined_pages
;
430 zone_pcp_update(zone
);
431 setup_per_zone_wmarks();
432 calculate_zone_inactive_ratio(zone
);
434 kswapd_run(zone_to_nid(zone
));
435 node_set_state(zone_to_nid(zone
), N_HIGH_MEMORY
);
438 if (need_zonelists_rebuild
)
439 build_all_zonelists();
441 vm_total_pages
= nr_free_pagecache_pages();
443 writeback_set_ratelimit();
446 memory_notify(MEM_ONLINE
, &arg
);
450 #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
452 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
453 static pg_data_t __ref
*hotadd_new_pgdat(int nid
, u64 start
)
455 struct pglist_data
*pgdat
;
456 unsigned long zones_size
[MAX_NR_ZONES
] = {0};
457 unsigned long zholes_size
[MAX_NR_ZONES
] = {0};
458 unsigned long start_pfn
= start
>> PAGE_SHIFT
;
460 pgdat
= arch_alloc_nodedata(nid
);
464 arch_refresh_nodedata(nid
, pgdat
);
466 /* we can use NODE_DATA(nid) from here */
468 /* init node's zones as empty zones, we don't have any present pages.*/
469 free_area_init_node(nid
, zones_size
, start_pfn
, zholes_size
);
474 static void rollback_node_hotadd(int nid
, pg_data_t
*pgdat
)
476 arch_refresh_nodedata(nid
, NULL
);
477 arch_free_nodedata(pgdat
);
482 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
483 int __ref
add_memory(int nid
, u64 start
, u64 size
)
485 pg_data_t
*pgdat
= NULL
;
487 struct resource
*res
;
492 res
= register_memory_resource(start
, size
);
497 if (!node_online(nid
)) {
498 pgdat
= hotadd_new_pgdat(nid
, start
);
505 /* call arch's memory hotadd */
506 ret
= arch_add_memory(nid
, start
, size
);
511 /* we online node here. we can't roll back from here. */
512 node_set_online(nid
);
515 ret
= register_one_node(nid
);
517 * If sysfs file of new node can't create, cpu on the node
518 * can't be hot-added. There is no rollback way now.
519 * So, check by BUG_ON() to catch it reluctantly..
527 /* rollback pgdat allocation and others */
529 rollback_node_hotadd(nid
, pgdat
);
531 release_memory_resource(res
);
534 unlock_system_sleep();
537 EXPORT_SYMBOL_GPL(add_memory
);
539 #ifdef CONFIG_MEMORY_HOTREMOVE
541 * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy
542 * set and the size of the free page is given by page_order(). Using this,
543 * the function determines if the pageblock contains only free pages.
544 * Due to buddy contraints, a free page at least the size of a pageblock will
545 * be located at the start of the pageblock
547 static inline int pageblock_free(struct page
*page
)
549 return PageBuddy(page
) && page_order(page
) >= pageblock_order
;
552 /* Return the start of the next active pageblock after a given page */
553 static struct page
*next_active_pageblock(struct page
*page
)
555 int pageblocks_stride
;
557 /* Ensure the starting page is pageblock-aligned */
558 BUG_ON(page_to_pfn(page
) & (pageblock_nr_pages
- 1));
560 /* Move forward by at least 1 * pageblock_nr_pages */
561 pageblocks_stride
= 1;
563 /* If the entire pageblock is free, move to the end of free page */
564 if (pageblock_free(page
))
565 pageblocks_stride
+= page_order(page
) - pageblock_order
;
567 return page
+ (pageblocks_stride
* pageblock_nr_pages
);
570 /* Checks if this range of memory is likely to be hot-removable. */
571 int is_mem_section_removable(unsigned long start_pfn
, unsigned long nr_pages
)
574 struct page
*page
= pfn_to_page(start_pfn
);
575 struct page
*end_page
= page
+ nr_pages
;
577 /* Check the starting page of each pageblock within the range */
578 for (; page
< end_page
; page
= next_active_pageblock(page
)) {
579 type
= get_pageblock_migratetype(page
);
582 * A pageblock containing MOVABLE or free pages is considered
585 if (type
!= MIGRATE_MOVABLE
&& !pageblock_free(page
))
589 * A pageblock starting with a PageReserved page is not
590 * considered removable.
592 if (PageReserved(page
))
596 /* All pageblocks in the memory block are likely to be hot-removable */
601 * Confirm all pages in a range [start, end) is belongs to the same zone.
603 static int test_pages_in_a_zone(unsigned long start_pfn
, unsigned long end_pfn
)
606 struct zone
*zone
= NULL
;
609 for (pfn
= start_pfn
;
611 pfn
+= MAX_ORDER_NR_PAGES
) {
613 /* This is just a CONFIG_HOLES_IN_ZONE check.*/
614 while ((i
< MAX_ORDER_NR_PAGES
) && !pfn_valid_within(pfn
+ i
))
616 if (i
== MAX_ORDER_NR_PAGES
)
618 page
= pfn_to_page(pfn
+ i
);
619 if (zone
&& page_zone(page
) != zone
)
621 zone
= page_zone(page
);
627 * Scanning pfn is much easier than scanning lru list.
628 * Scan pfn from start to end and Find LRU page.
630 int scan_lru_pages(unsigned long start
, unsigned long end
)
634 for (pfn
= start
; pfn
< end
; pfn
++) {
635 if (pfn_valid(pfn
)) {
636 page
= pfn_to_page(pfn
);
645 hotremove_migrate_alloc(struct page
*page
, unsigned long private, int **x
)
647 /* This should be improooooved!! */
648 return alloc_page(GFP_HIGHUSER_MOVABLE
);
651 #define NR_OFFLINE_AT_ONCE_PAGES (256)
653 do_migrate_range(unsigned long start_pfn
, unsigned long end_pfn
)
657 int move_pages
= NR_OFFLINE_AT_ONCE_PAGES
;
662 for (pfn
= start_pfn
; pfn
< end_pfn
&& move_pages
> 0; pfn
++) {
665 page
= pfn_to_page(pfn
);
666 if (!page_count(page
))
669 * We can skip free pages. And we can only deal with pages on
672 ret
= isolate_lru_page(page
);
673 if (!ret
) { /* Success */
674 list_add_tail(&page
->lru
, &source
);
676 inc_zone_page_state(page
, NR_ISOLATED_ANON
+
677 page_is_file_cache(page
));
680 /* Becasue we don't have big zone->lock. we should
681 check this again here. */
682 if (page_count(page
))
684 #ifdef CONFIG_DEBUG_VM
685 printk(KERN_INFO
"removing from LRU failed"
687 pfn
, page_count(page
), page
->flags
);
693 if (!list_empty(&source
))
694 putback_lru_pages(&source
);
698 if (list_empty(&source
))
700 /* this function returns # of failed pages */
701 ret
= migrate_pages(&source
, hotremove_migrate_alloc
, 0);
708 * remove from free_area[] and mark all as Reserved.
711 offline_isolated_pages_cb(unsigned long start
, unsigned long nr_pages
,
714 __offline_isolated_pages(start
, start
+ nr_pages
);
719 offline_isolated_pages(unsigned long start_pfn
, unsigned long end_pfn
)
721 walk_system_ram_range(start_pfn
, end_pfn
- start_pfn
, NULL
,
722 offline_isolated_pages_cb
);
726 * Check all pages in range, recoreded as memory resource, are isolated.
729 check_pages_isolated_cb(unsigned long start_pfn
, unsigned long nr_pages
,
733 long offlined
= *(long *)data
;
734 ret
= test_pages_isolated(start_pfn
, start_pfn
+ nr_pages
);
737 *(long *)data
+= offlined
;
742 check_pages_isolated(unsigned long start_pfn
, unsigned long end_pfn
)
747 ret
= walk_system_ram_range(start_pfn
, end_pfn
- start_pfn
, &offlined
,
748 check_pages_isolated_cb
);
750 offlined
= (long)ret
;
754 int offline_pages(unsigned long start_pfn
,
755 unsigned long end_pfn
, unsigned long timeout
)
757 unsigned long pfn
, nr_pages
, expire
;
759 int ret
, drain
, retry_max
, node
;
761 struct memory_notify arg
;
763 BUG_ON(start_pfn
>= end_pfn
);
764 /* at least, alignment against pageblock is necessary */
765 if (!IS_ALIGNED(start_pfn
, pageblock_nr_pages
))
767 if (!IS_ALIGNED(end_pfn
, pageblock_nr_pages
))
769 /* This makes hotplug much easier...and readable.
770 we assume this for now. .*/
771 if (!test_pages_in_a_zone(start_pfn
, end_pfn
))
776 zone
= page_zone(pfn_to_page(start_pfn
));
777 node
= zone_to_nid(zone
);
778 nr_pages
= end_pfn
- start_pfn
;
780 /* set above range as isolated */
781 ret
= start_isolate_page_range(start_pfn
, end_pfn
);
785 arg
.start_pfn
= start_pfn
;
786 arg
.nr_pages
= nr_pages
;
787 arg
.status_change_nid
= -1;
788 if (nr_pages
>= node_present_pages(node
))
789 arg
.status_change_nid
= node
;
791 ret
= memory_notify(MEM_GOING_OFFLINE
, &arg
);
792 ret
= notifier_to_errno(ret
);
797 expire
= jiffies
+ timeout
;
801 /* start memory hot removal */
803 if (time_after(jiffies
, expire
))
806 if (signal_pending(current
))
811 flush_scheduled_work();
816 pfn
= scan_lru_pages(start_pfn
, end_pfn
);
817 if (pfn
) { /* We have page on LRU */
818 ret
= do_migrate_range(pfn
, end_pfn
);
824 if (--retry_max
== 0)
831 /* drain all zone's lru pagevec, this is asyncronous... */
833 flush_scheduled_work();
835 /* drain pcp pages , this is synchrouns. */
838 offlined_pages
= check_pages_isolated(start_pfn
, end_pfn
);
839 if (offlined_pages
< 0) {
843 printk(KERN_INFO
"Offlined Pages %ld\n", offlined_pages
);
844 /* Ok, all of our target is islaoted.
845 We cannot do rollback at this point. */
846 offline_isolated_pages(start_pfn
, end_pfn
);
847 /* reset pagetype flags and makes migrate type to be MOVABLE */
848 undo_isolate_page_range(start_pfn
, end_pfn
);
849 /* removal success */
850 zone
->present_pages
-= offlined_pages
;
851 zone
->zone_pgdat
->node_present_pages
-= offlined_pages
;
852 totalram_pages
-= offlined_pages
;
854 setup_per_zone_wmarks();
855 calculate_zone_inactive_ratio(zone
);
856 if (!node_present_pages(node
)) {
857 node_clear_state(node
, N_HIGH_MEMORY
);
861 vm_total_pages
= nr_free_pagecache_pages();
862 writeback_set_ratelimit();
864 memory_notify(MEM_OFFLINE
, &arg
);
865 unlock_system_sleep();
869 printk(KERN_INFO
"memory offlining %lx to %lx failed\n",
871 memory_notify(MEM_CANCEL_OFFLINE
, &arg
);
872 /* pushback to free area */
873 undo_isolate_page_range(start_pfn
, end_pfn
);
876 unlock_system_sleep();
880 int remove_memory(u64 start
, u64 size
)
882 unsigned long start_pfn
, end_pfn
;
884 start_pfn
= PFN_DOWN(start
);
885 end_pfn
= start_pfn
+ PFN_DOWN(size
);
886 return offline_pages(start_pfn
, end_pfn
, 120 * HZ
);
889 int remove_memory(u64 start
, u64 size
)
893 #endif /* CONFIG_MEMORY_HOTREMOVE */
894 EXPORT_SYMBOL_GPL(remove_memory
);