1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/mm/memory_hotplug.c
8 #include <linux/stddef.h>
10 #include <linux/sched/signal.h>
11 #include <linux/swap.h>
12 #include <linux/interrupt.h>
13 #include <linux/pagemap.h>
14 #include <linux/compiler.h>
15 #include <linux/export.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/memremap.h>
22 #include <linux/memory_hotplug.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/compaction.h>
36 #include <linux/rmap.h>
37 #include <linux/module.h>
39 #include <asm/tlbflush.h>
45 MEMMAP_ON_MEMORY_DISABLE
= 0,
46 MEMMAP_ON_MEMORY_ENABLE
,
47 MEMMAP_ON_MEMORY_FORCE
,
50 static int memmap_mode __read_mostly
= MEMMAP_ON_MEMORY_DISABLE
;
52 static inline unsigned long memory_block_memmap_size(void)
54 return PHYS_PFN(memory_block_size_bytes()) * sizeof(struct page
);
57 static inline unsigned long memory_block_memmap_on_memory_pages(void)
59 unsigned long nr_pages
= PFN_UP(memory_block_memmap_size());
62 * In "forced" memmap_on_memory mode, we add extra pages to align the
63 * vmemmap size to cover full pageblocks. That way, we can add memory
64 * even if the vmemmap size is not properly aligned, however, we might waste
67 if (memmap_mode
== MEMMAP_ON_MEMORY_FORCE
)
68 return pageblock_align(nr_pages
);
72 #ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
74 * memory_hotplug.memmap_on_memory parameter
76 static int set_memmap_mode(const char *val
, const struct kernel_param
*kp
)
81 if (sysfs_streq(val
, "force") || sysfs_streq(val
, "FORCE")) {
82 mode
= MEMMAP_ON_MEMORY_FORCE
;
84 ret
= kstrtobool(val
, &enabled
);
88 mode
= MEMMAP_ON_MEMORY_ENABLE
;
90 mode
= MEMMAP_ON_MEMORY_DISABLE
;
92 *((int *)kp
->arg
) = mode
;
93 if (mode
== MEMMAP_ON_MEMORY_FORCE
) {
94 unsigned long memmap_pages
= memory_block_memmap_on_memory_pages();
96 pr_info_once("Memory hotplug will waste %ld pages in each memory block\n",
97 memmap_pages
- PFN_UP(memory_block_memmap_size()));
102 static int get_memmap_mode(char *buffer
, const struct kernel_param
*kp
)
104 int mode
= *((int *)kp
->arg
);
106 if (mode
== MEMMAP_ON_MEMORY_FORCE
)
107 return sprintf(buffer
, "force\n");
108 return sprintf(buffer
, "%c\n", mode
? 'Y' : 'N');
111 static const struct kernel_param_ops memmap_mode_ops
= {
112 .set
= set_memmap_mode
,
113 .get
= get_memmap_mode
,
115 module_param_cb(memmap_on_memory
, &memmap_mode_ops
, &memmap_mode
, 0444);
116 MODULE_PARM_DESC(memmap_on_memory
, "Enable memmap on memory for memory hotplug\n"
117 "With value \"force\" it could result in memory wastage due "
118 "to memmap size limitations (Y/N/force)");
120 static inline bool mhp_memmap_on_memory(void)
122 return memmap_mode
!= MEMMAP_ON_MEMORY_DISABLE
;
125 static inline bool mhp_memmap_on_memory(void)
132 ONLINE_POLICY_CONTIG_ZONES
= 0,
133 ONLINE_POLICY_AUTO_MOVABLE
,
136 static const char * const online_policy_to_str
[] = {
137 [ONLINE_POLICY_CONTIG_ZONES
] = "contig-zones",
138 [ONLINE_POLICY_AUTO_MOVABLE
] = "auto-movable",
141 static int set_online_policy(const char *val
, const struct kernel_param
*kp
)
143 int ret
= sysfs_match_string(online_policy_to_str
, val
);
147 *((int *)kp
->arg
) = ret
;
151 static int get_online_policy(char *buffer
, const struct kernel_param
*kp
)
153 return sprintf(buffer
, "%s\n", online_policy_to_str
[*((int *)kp
->arg
)]);
157 * memory_hotplug.online_policy: configure online behavior when onlining without
158 * specifying a zone (MMOP_ONLINE)
160 * "contig-zones": keep zone contiguous
161 * "auto-movable": online memory to ZONE_MOVABLE if the configuration
162 * (auto_movable_ratio, auto_movable_numa_aware) allows for it
164 static int online_policy __read_mostly
= ONLINE_POLICY_CONTIG_ZONES
;
165 static const struct kernel_param_ops online_policy_ops
= {
166 .set
= set_online_policy
,
167 .get
= get_online_policy
,
169 module_param_cb(online_policy
, &online_policy_ops
, &online_policy
, 0644);
170 MODULE_PARM_DESC(online_policy
,
171 "Set the online policy (\"contig-zones\", \"auto-movable\") "
172 "Default: \"contig-zones\"");
175 * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio
177 * The ratio represent an upper limit and the kernel might decide to not
178 * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory
179 * doesn't allow for more MOVABLE memory.
181 static unsigned int auto_movable_ratio __read_mostly
= 301;
182 module_param(auto_movable_ratio
, uint
, 0644);
183 MODULE_PARM_DESC(auto_movable_ratio
,
184 "Set the maximum ratio of MOVABLE:KERNEL memory in the system "
185 "in percent for \"auto-movable\" online policy. Default: 301");
188 * memory_hotplug.auto_movable_numa_aware: consider numa node stats
191 static bool auto_movable_numa_aware __read_mostly
= true;
192 module_param(auto_movable_numa_aware
, bool, 0644);
193 MODULE_PARM_DESC(auto_movable_numa_aware
,
194 "Consider numa node stats in addition to global stats in "
195 "\"auto-movable\" online policy. Default: true");
196 #endif /* CONFIG_NUMA */
199 * online_page_callback contains pointer to current page onlining function.
200 * Initially it is generic_online_page(). If it is required it could be
201 * changed by calling set_online_page_callback() for callback registration
202 * and restore_online_page_callback() for generic callback restore.
205 static online_page_callback_t online_page_callback
= generic_online_page
;
206 static DEFINE_MUTEX(online_page_callback_lock
);
208 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock
);
210 void get_online_mems(void)
212 percpu_down_read(&mem_hotplug_lock
);
215 void put_online_mems(void)
217 percpu_up_read(&mem_hotplug_lock
);
220 bool movable_node_enabled
= false;
222 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
223 int mhp_default_online_type
= MMOP_OFFLINE
;
225 int mhp_default_online_type
= MMOP_ONLINE
;
228 static int __init
setup_memhp_default_state(char *str
)
230 const int online_type
= mhp_online_type_from_str(str
);
232 if (online_type
>= 0)
233 mhp_default_online_type
= online_type
;
237 __setup("memhp_default_state=", setup_memhp_default_state
);
239 void mem_hotplug_begin(void)
242 percpu_down_write(&mem_hotplug_lock
);
245 void mem_hotplug_done(void)
247 percpu_up_write(&mem_hotplug_lock
);
251 u64 max_mem_size
= U64_MAX
;
253 /* add this memory to iomem resource */
254 static struct resource
*register_memory_resource(u64 start
, u64 size
,
255 const char *resource_name
)
257 struct resource
*res
;
258 unsigned long flags
= IORESOURCE_SYSTEM_RAM
| IORESOURCE_BUSY
;
260 if (strcmp(resource_name
, "System RAM"))
261 flags
|= IORESOURCE_SYSRAM_DRIVER_MANAGED
;
263 if (!mhp_range_allowed(start
, size
, true))
264 return ERR_PTR(-E2BIG
);
267 * Make sure value parsed from 'mem=' only restricts memory adding
268 * while booting, so that memory hotplug won't be impacted. Please
269 * refer to document of 'mem=' in kernel-parameters.txt for more
272 if (start
+ size
> max_mem_size
&& system_state
< SYSTEM_RUNNING
)
273 return ERR_PTR(-E2BIG
);
276 * Request ownership of the new memory range. This might be
277 * a child of an existing resource that was present but
278 * not marked as busy.
280 res
= __request_region(&iomem_resource
, start
, size
,
281 resource_name
, flags
);
284 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
285 start
, start
+ size
);
286 return ERR_PTR(-EEXIST
);
291 static void release_memory_resource(struct resource
*res
)
295 release_resource(res
);
299 static int check_pfn_span(unsigned long pfn
, unsigned long nr_pages
)
302 * Disallow all operations smaller than a sub-section and only
303 * allow operations smaller than a section for
304 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
305 * enforces a larger memory_block_size_bytes() granularity for
306 * memory that will be marked online, so this check should only
307 * fire for direct arch_{add,remove}_memory() users outside of
308 * add_memory_resource().
310 unsigned long min_align
;
312 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP
))
313 min_align
= PAGES_PER_SUBSECTION
;
315 min_align
= PAGES_PER_SECTION
;
316 if (!IS_ALIGNED(pfn
| nr_pages
, min_align
))
322 * Return page for the valid pfn only if the page is online. All pfn
323 * walkers which rely on the fully initialized page->flags and others
324 * should use this rather than pfn_valid && pfn_to_page
326 struct page
*pfn_to_online_page(unsigned long pfn
)
328 unsigned long nr
= pfn_to_section_nr(pfn
);
329 struct dev_pagemap
*pgmap
;
330 struct mem_section
*ms
;
332 if (nr
>= NR_MEM_SECTIONS
)
335 ms
= __nr_to_section(nr
);
336 if (!online_section(ms
))
340 * Save some code text when online_section() +
341 * pfn_section_valid() are sufficient.
343 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID
) && !pfn_valid(pfn
))
346 if (!pfn_section_valid(ms
, pfn
))
349 if (!online_device_section(ms
))
350 return pfn_to_page(pfn
);
353 * Slowpath: when ZONE_DEVICE collides with
354 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in
355 * the section may be 'offline' but 'valid'. Only
356 * get_dev_pagemap() can determine sub-section online status.
358 pgmap
= get_dev_pagemap(pfn
, NULL
);
359 put_dev_pagemap(pgmap
);
361 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */
365 return pfn_to_page(pfn
);
367 EXPORT_SYMBOL_GPL(pfn_to_online_page
);
369 int __ref
__add_pages(int nid
, unsigned long pfn
, unsigned long nr_pages
,
370 struct mhp_params
*params
)
372 const unsigned long end_pfn
= pfn
+ nr_pages
;
373 unsigned long cur_nr_pages
;
375 struct vmem_altmap
*altmap
= params
->altmap
;
377 if (WARN_ON_ONCE(!pgprot_val(params
->pgprot
)))
380 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn
), nr_pages
* PAGE_SIZE
, false));
384 * Validate altmap is within bounds of the total request
386 if (altmap
->base_pfn
!= pfn
387 || vmem_altmap_offset(altmap
) > nr_pages
) {
388 pr_warn_once("memory add fail, invalid altmap\n");
394 if (check_pfn_span(pfn
, nr_pages
)) {
395 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__
, pfn
, pfn
+ nr_pages
- 1);
399 for (; pfn
< end_pfn
; pfn
+= cur_nr_pages
) {
400 /* Select all remaining pages up to the next section boundary */
401 cur_nr_pages
= min(end_pfn
- pfn
,
402 SECTION_ALIGN_UP(pfn
+ 1) - pfn
);
403 err
= sparse_add_section(nid
, pfn
, cur_nr_pages
, altmap
,
409 vmemmap_populate_print_last();
413 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
414 static unsigned long find_smallest_section_pfn(int nid
, struct zone
*zone
,
415 unsigned long start_pfn
,
416 unsigned long end_pfn
)
418 for (; start_pfn
< end_pfn
; start_pfn
+= PAGES_PER_SUBSECTION
) {
419 if (unlikely(!pfn_to_online_page(start_pfn
)))
422 if (unlikely(pfn_to_nid(start_pfn
) != nid
))
425 if (zone
!= page_zone(pfn_to_page(start_pfn
)))
434 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
435 static unsigned long find_biggest_section_pfn(int nid
, struct zone
*zone
,
436 unsigned long start_pfn
,
437 unsigned long end_pfn
)
441 /* pfn is the end pfn of a memory section. */
443 for (; pfn
>= start_pfn
; pfn
-= PAGES_PER_SUBSECTION
) {
444 if (unlikely(!pfn_to_online_page(pfn
)))
447 if (unlikely(pfn_to_nid(pfn
) != nid
))
450 if (zone
!= page_zone(pfn_to_page(pfn
)))
459 static void shrink_zone_span(struct zone
*zone
, unsigned long start_pfn
,
460 unsigned long end_pfn
)
463 int nid
= zone_to_nid(zone
);
465 if (zone
->zone_start_pfn
== start_pfn
) {
467 * If the section is smallest section in the zone, it need
468 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
469 * In this case, we find second smallest valid mem_section
470 * for shrinking zone.
472 pfn
= find_smallest_section_pfn(nid
, zone
, end_pfn
,
475 zone
->spanned_pages
= zone_end_pfn(zone
) - pfn
;
476 zone
->zone_start_pfn
= pfn
;
478 zone
->zone_start_pfn
= 0;
479 zone
->spanned_pages
= 0;
481 } else if (zone_end_pfn(zone
) == end_pfn
) {
483 * If the section is biggest section in the zone, it need
484 * shrink zone->spanned_pages.
485 * In this case, we find second biggest valid mem_section for
488 pfn
= find_biggest_section_pfn(nid
, zone
, zone
->zone_start_pfn
,
491 zone
->spanned_pages
= pfn
- zone
->zone_start_pfn
+ 1;
493 zone
->zone_start_pfn
= 0;
494 zone
->spanned_pages
= 0;
499 static void update_pgdat_span(struct pglist_data
*pgdat
)
501 unsigned long node_start_pfn
= 0, node_end_pfn
= 0;
504 for (zone
= pgdat
->node_zones
;
505 zone
< pgdat
->node_zones
+ MAX_NR_ZONES
; zone
++) {
506 unsigned long end_pfn
= zone_end_pfn(zone
);
508 /* No need to lock the zones, they can't change. */
509 if (!zone
->spanned_pages
)
512 node_start_pfn
= zone
->zone_start_pfn
;
513 node_end_pfn
= end_pfn
;
517 if (end_pfn
> node_end_pfn
)
518 node_end_pfn
= end_pfn
;
519 if (zone
->zone_start_pfn
< node_start_pfn
)
520 node_start_pfn
= zone
->zone_start_pfn
;
523 pgdat
->node_start_pfn
= node_start_pfn
;
524 pgdat
->node_spanned_pages
= node_end_pfn
- node_start_pfn
;
527 void __ref
remove_pfn_range_from_zone(struct zone
*zone
,
528 unsigned long start_pfn
,
529 unsigned long nr_pages
)
531 const unsigned long end_pfn
= start_pfn
+ nr_pages
;
532 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
533 unsigned long pfn
, cur_nr_pages
;
535 /* Poison struct pages because they are now uninitialized again. */
536 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= cur_nr_pages
) {
539 /* Select all remaining pages up to the next section boundary */
541 min(end_pfn
- pfn
, SECTION_ALIGN_UP(pfn
+ 1) - pfn
);
542 page_init_poison(pfn_to_page(pfn
),
543 sizeof(struct page
) * cur_nr_pages
);
547 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
548 * we will not try to shrink the zones - which is okay as
549 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
551 if (zone_is_zone_device(zone
))
554 clear_zone_contiguous(zone
);
556 shrink_zone_span(zone
, start_pfn
, start_pfn
+ nr_pages
);
557 update_pgdat_span(pgdat
);
559 set_zone_contiguous(zone
);
563 * __remove_pages() - remove sections of pages
564 * @pfn: starting pageframe (must be aligned to start of a section)
565 * @nr_pages: number of pages to remove (must be multiple of section size)
566 * @altmap: alternative device page map or %NULL if default memmap is used
568 * Generic helper function to remove section mappings and sysfs entries
569 * for the section of the memory we are removing. Caller needs to make
570 * sure that pages are marked reserved and zones are adjust properly by
571 * calling offline_pages().
573 void __remove_pages(unsigned long pfn
, unsigned long nr_pages
,
574 struct vmem_altmap
*altmap
)
576 const unsigned long end_pfn
= pfn
+ nr_pages
;
577 unsigned long cur_nr_pages
;
579 if (check_pfn_span(pfn
, nr_pages
)) {
580 WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__
, pfn
, pfn
+ nr_pages
- 1);
584 for (; pfn
< end_pfn
; pfn
+= cur_nr_pages
) {
586 /* Select all remaining pages up to the next section boundary */
587 cur_nr_pages
= min(end_pfn
- pfn
,
588 SECTION_ALIGN_UP(pfn
+ 1) - pfn
);
589 sparse_remove_section(pfn
, cur_nr_pages
, altmap
);
593 int set_online_page_callback(online_page_callback_t callback
)
598 mutex_lock(&online_page_callback_lock
);
600 if (online_page_callback
== generic_online_page
) {
601 online_page_callback
= callback
;
605 mutex_unlock(&online_page_callback_lock
);
610 EXPORT_SYMBOL_GPL(set_online_page_callback
);
612 int restore_online_page_callback(online_page_callback_t callback
)
617 mutex_lock(&online_page_callback_lock
);
619 if (online_page_callback
== callback
) {
620 online_page_callback
= generic_online_page
;
624 mutex_unlock(&online_page_callback_lock
);
629 EXPORT_SYMBOL_GPL(restore_online_page_callback
);
631 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
632 void __ref
generic_online_page(struct page
*page
, unsigned int order
)
634 __free_pages_core(page
, order
, MEMINIT_HOTPLUG
);
636 EXPORT_SYMBOL_GPL(generic_online_page
);
638 static void online_pages_range(unsigned long start_pfn
, unsigned long nr_pages
)
640 const unsigned long end_pfn
= start_pfn
+ nr_pages
;
644 * Online the pages in MAX_PAGE_ORDER aligned chunks. The callback might
645 * decide to not expose all pages to the buddy (e.g., expose them
646 * later). We account all pages as being online and belonging to this
648 * When using memmap_on_memory, the range might not be aligned to
649 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect
650 * this and the first chunk to online will be pageblock_nr_pages.
652 for (pfn
= start_pfn
; pfn
< end_pfn
;) {
656 * Free to online pages in the largest chunks alignment allows.
658 * __ffs() behaviour is undefined for 0. start == 0 is
659 * MAX_PAGE_ORDER-aligned, Set order to MAX_PAGE_ORDER for
663 order
= min_t(int, MAX_PAGE_ORDER
, __ffs(pfn
));
665 order
= MAX_PAGE_ORDER
;
667 (*online_page_callback
)(pfn_to_page(pfn
), order
);
668 pfn
+= (1UL << order
);
671 /* mark all involved sections as online */
672 online_mem_sections(start_pfn
, end_pfn
);
675 /* check which state of node_states will be changed when online memory */
676 static void node_states_check_changes_online(unsigned long nr_pages
,
677 struct zone
*zone
, struct memory_notify
*arg
)
679 int nid
= zone_to_nid(zone
);
681 arg
->status_change_nid
= NUMA_NO_NODE
;
682 arg
->status_change_nid_normal
= NUMA_NO_NODE
;
684 if (!node_state(nid
, N_MEMORY
))
685 arg
->status_change_nid
= nid
;
686 if (zone_idx(zone
) <= ZONE_NORMAL
&& !node_state(nid
, N_NORMAL_MEMORY
))
687 arg
->status_change_nid_normal
= nid
;
690 static void node_states_set_node(int node
, struct memory_notify
*arg
)
692 if (arg
->status_change_nid_normal
>= 0)
693 node_set_state(node
, N_NORMAL_MEMORY
);
695 if (arg
->status_change_nid
>= 0)
696 node_set_state(node
, N_MEMORY
);
699 static void __meminit
resize_zone_range(struct zone
*zone
, unsigned long start_pfn
,
700 unsigned long nr_pages
)
702 unsigned long old_end_pfn
= zone_end_pfn(zone
);
704 if (zone_is_empty(zone
) || start_pfn
< zone
->zone_start_pfn
)
705 zone
->zone_start_pfn
= start_pfn
;
707 zone
->spanned_pages
= max(start_pfn
+ nr_pages
, old_end_pfn
) - zone
->zone_start_pfn
;
710 static void __meminit
resize_pgdat_range(struct pglist_data
*pgdat
, unsigned long start_pfn
,
711 unsigned long nr_pages
)
713 unsigned long old_end_pfn
= pgdat_end_pfn(pgdat
);
715 if (!pgdat
->node_spanned_pages
|| start_pfn
< pgdat
->node_start_pfn
)
716 pgdat
->node_start_pfn
= start_pfn
;
718 pgdat
->node_spanned_pages
= max(start_pfn
+ nr_pages
, old_end_pfn
) - pgdat
->node_start_pfn
;
722 #ifdef CONFIG_ZONE_DEVICE
723 static void section_taint_zone_device(unsigned long pfn
)
725 struct mem_section
*ms
= __pfn_to_section(pfn
);
727 ms
->section_mem_map
|= SECTION_TAINT_ZONE_DEVICE
;
730 static inline void section_taint_zone_device(unsigned long pfn
)
736 * Associate the pfn range with the given zone, initializing the memmaps
737 * and resizing the pgdat/zone data to span the added pages. After this
738 * call, all affected pages are PageOffline().
740 * All aligned pageblocks are initialized to the specified migratetype
741 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
742 * zone stats (e.g., nr_isolate_pageblock) are touched.
744 void __ref
move_pfn_range_to_zone(struct zone
*zone
, unsigned long start_pfn
,
745 unsigned long nr_pages
,
746 struct vmem_altmap
*altmap
, int migratetype
)
748 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
749 int nid
= pgdat
->node_id
;
751 clear_zone_contiguous(zone
);
753 if (zone_is_empty(zone
))
754 init_currently_empty_zone(zone
, start_pfn
, nr_pages
);
755 resize_zone_range(zone
, start_pfn
, nr_pages
);
756 resize_pgdat_range(pgdat
, start_pfn
, nr_pages
);
759 * Subsection population requires care in pfn_to_online_page().
760 * Set the taint to enable the slow path detection of
761 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE}
764 if (zone_is_zone_device(zone
)) {
765 if (!IS_ALIGNED(start_pfn
, PAGES_PER_SECTION
))
766 section_taint_zone_device(start_pfn
);
767 if (!IS_ALIGNED(start_pfn
+ nr_pages
, PAGES_PER_SECTION
))
768 section_taint_zone_device(start_pfn
+ nr_pages
);
772 * TODO now we have a visible range of pages which are not associated
773 * with their zone properly. Not nice but set_pfnblock_flags_mask
774 * expects the zone spans the pfn range. All the pages in the range
775 * are reserved so nobody should be touching them so we should be safe
777 memmap_init_range(nr_pages
, nid
, zone_idx(zone
), start_pfn
, 0,
778 MEMINIT_HOTPLUG
, altmap
, migratetype
);
780 set_zone_contiguous(zone
);
783 struct auto_movable_stats
{
784 unsigned long kernel_early_pages
;
785 unsigned long movable_pages
;
788 static void auto_movable_stats_account_zone(struct auto_movable_stats
*stats
,
791 if (zone_idx(zone
) == ZONE_MOVABLE
) {
792 stats
->movable_pages
+= zone
->present_pages
;
794 stats
->kernel_early_pages
+= zone
->present_early_pages
;
797 * CMA pages (never on hotplugged memory) behave like
800 stats
->movable_pages
+= zone
->cma_pages
;
801 stats
->kernel_early_pages
-= zone
->cma_pages
;
802 #endif /* CONFIG_CMA */
805 struct auto_movable_group_stats
{
806 unsigned long movable_pages
;
807 unsigned long req_kernel_early_pages
;
810 static int auto_movable_stats_account_group(struct memory_group
*group
,
813 const int ratio
= READ_ONCE(auto_movable_ratio
);
814 struct auto_movable_group_stats
*stats
= arg
;
818 * We don't support modifying the config while the auto-movable online
819 * policy is already enabled. Just avoid the division by zero below.
825 * Calculate how many early kernel pages this group requires to
826 * satisfy the configured zone ratio.
828 pages
= group
->present_movable_pages
* 100 / ratio
;
829 pages
-= group
->present_kernel_pages
;
832 stats
->req_kernel_early_pages
+= pages
;
833 stats
->movable_pages
+= group
->present_movable_pages
;
837 static bool auto_movable_can_online_movable(int nid
, struct memory_group
*group
,
838 unsigned long nr_pages
)
840 unsigned long kernel_early_pages
, movable_pages
;
841 struct auto_movable_group_stats group_stats
= {};
842 struct auto_movable_stats stats
= {};
846 /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */
847 if (nid
== NUMA_NO_NODE
) {
848 /* TODO: cache values */
849 for_each_populated_zone(zone
)
850 auto_movable_stats_account_zone(&stats
, zone
);
852 for (i
= 0; i
< MAX_NR_ZONES
; i
++) {
853 pg_data_t
*pgdat
= NODE_DATA(nid
);
855 zone
= pgdat
->node_zones
+ i
;
856 if (populated_zone(zone
))
857 auto_movable_stats_account_zone(&stats
, zone
);
861 kernel_early_pages
= stats
.kernel_early_pages
;
862 movable_pages
= stats
.movable_pages
;
865 * Kernel memory inside dynamic memory group allows for more MOVABLE
866 * memory within the same group. Remove the effect of all but the
867 * current group from the stats.
869 walk_dynamic_memory_groups(nid
, auto_movable_stats_account_group
,
870 group
, &group_stats
);
871 if (kernel_early_pages
<= group_stats
.req_kernel_early_pages
)
873 kernel_early_pages
-= group_stats
.req_kernel_early_pages
;
874 movable_pages
-= group_stats
.movable_pages
;
876 if (group
&& group
->is_dynamic
)
877 kernel_early_pages
+= group
->present_kernel_pages
;
880 * Test if we could online the given number of pages to ZONE_MOVABLE
881 * and still stay in the configured ratio.
883 movable_pages
+= nr_pages
;
884 return movable_pages
<= (auto_movable_ratio
* kernel_early_pages
) / 100;
888 * Returns a default kernel memory zone for the given pfn range.
889 * If no kernel zone covers this pfn range it will automatically go
890 * to the ZONE_NORMAL.
892 static struct zone
*default_kernel_zone_for_pfn(int nid
, unsigned long start_pfn
,
893 unsigned long nr_pages
)
895 struct pglist_data
*pgdat
= NODE_DATA(nid
);
898 for (zid
= 0; zid
< ZONE_NORMAL
; zid
++) {
899 struct zone
*zone
= &pgdat
->node_zones
[zid
];
901 if (zone_intersects(zone
, start_pfn
, nr_pages
))
905 return &pgdat
->node_zones
[ZONE_NORMAL
];
909 * Determine to which zone to online memory dynamically based on user
910 * configuration and system stats. We care about the following ratio:
914 * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in
915 * one of the kernel zones. CMA pages inside one of the kernel zones really
916 * behaves like ZONE_MOVABLE, so we treat them accordingly.
918 * We don't allow for hotplugged memory in a KERNEL zone to increase the
919 * amount of MOVABLE memory we can have, so we end up with:
921 * MOVABLE : KERNEL_EARLY
923 * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze
924 * boot. We base our calculation on KERNEL_EARLY internally, because:
926 * a) Hotplugged memory in one of the kernel zones can sometimes still get
927 * hotunplugged, especially when hot(un)plugging individual memory blocks.
928 * There is no coordination across memory devices, therefore "automatic"
929 * hotunplugging, as implemented in hypervisors, could result in zone
931 * b) Early/boot memory in one of the kernel zones can usually not get
932 * hotunplugged again (e.g., no firmware interface to unplug, fragmented
933 * with unmovable allocations). While there are corner cases where it might
934 * still work, it is barely relevant in practice.
936 * Exceptions are dynamic memory groups, which allow for more MOVABLE
937 * memory within the same memory group -- because in that case, there is
938 * coordination within the single memory device managed by a single driver.
940 * We rely on "present pages" instead of "managed pages", as the latter is
941 * highly unreliable and dynamic in virtualized environments, and does not
942 * consider boot time allocations. For example, memory ballooning adjusts the
943 * managed pages when inflating/deflating the balloon, and balloon compaction
944 * can even migrate inflated pages between zones.
946 * Using "present pages" is better but some things to keep in mind are:
948 * a) Some memblock allocations, such as for the crashkernel area, are
949 * effectively unused by the kernel, yet they account to "present pages".
950 * Fortunately, these allocations are comparatively small in relevant setups
951 * (e.g., fraction of system memory).
952 * b) Some hotplugged memory blocks in virtualized environments, esecially
953 * hotplugged by virtio-mem, look like they are completely present, however,
954 * only parts of the memory block are actually currently usable.
955 * "present pages" is an upper limit that can get reached at runtime. As
956 * we base our calculations on KERNEL_EARLY, this is not an issue.
958 static struct zone
*auto_movable_zone_for_pfn(int nid
,
959 struct memory_group
*group
,
961 unsigned long nr_pages
)
963 unsigned long online_pages
= 0, max_pages
, end_pfn
;
966 if (!auto_movable_ratio
)
969 if (group
&& !group
->is_dynamic
) {
970 max_pages
= group
->s
.max_pages
;
971 online_pages
= group
->present_movable_pages
;
973 /* If anything is !MOVABLE online the rest !MOVABLE. */
974 if (group
->present_kernel_pages
)
976 } else if (!group
|| group
->d
.unit_pages
== nr_pages
) {
977 max_pages
= nr_pages
;
979 max_pages
= group
->d
.unit_pages
;
981 * Take a look at all online sections in the current unit.
982 * We can safely assume that all pages within a section belong
983 * to the same zone, because dynamic memory groups only deal
984 * with hotplugged memory.
986 pfn
= ALIGN_DOWN(pfn
, group
->d
.unit_pages
);
987 end_pfn
= pfn
+ group
->d
.unit_pages
;
988 for (; pfn
< end_pfn
; pfn
+= PAGES_PER_SECTION
) {
989 page
= pfn_to_online_page(pfn
);
992 /* If anything is !MOVABLE online the rest !MOVABLE. */
993 if (!is_zone_movable_page(page
))
995 online_pages
+= PAGES_PER_SECTION
;
1000 * Online MOVABLE if we could *currently* online all remaining parts
1001 * MOVABLE. We expect to (add+) online them immediately next, so if
1002 * nobody interferes, all will be MOVABLE if possible.
1004 nr_pages
= max_pages
- online_pages
;
1005 if (!auto_movable_can_online_movable(NUMA_NO_NODE
, group
, nr_pages
))
1009 if (auto_movable_numa_aware
&&
1010 !auto_movable_can_online_movable(nid
, group
, nr_pages
))
1012 #endif /* CONFIG_NUMA */
1014 return &NODE_DATA(nid
)->node_zones
[ZONE_MOVABLE
];
1016 return default_kernel_zone_for_pfn(nid
, pfn
, nr_pages
);
1019 static inline struct zone
*default_zone_for_pfn(int nid
, unsigned long start_pfn
,
1020 unsigned long nr_pages
)
1022 struct zone
*kernel_zone
= default_kernel_zone_for_pfn(nid
, start_pfn
,
1024 struct zone
*movable_zone
= &NODE_DATA(nid
)->node_zones
[ZONE_MOVABLE
];
1025 bool in_kernel
= zone_intersects(kernel_zone
, start_pfn
, nr_pages
);
1026 bool in_movable
= zone_intersects(movable_zone
, start_pfn
, nr_pages
);
1029 * We inherit the existing zone in a simple case where zones do not
1030 * overlap in the given range
1032 if (in_kernel
^ in_movable
)
1033 return (in_kernel
) ? kernel_zone
: movable_zone
;
1036 * If the range doesn't belong to any zone or two zones overlap in the
1037 * given range then we use movable zone only if movable_node is
1038 * enabled because we always online to a kernel zone by default.
1040 return movable_node_enabled
? movable_zone
: kernel_zone
;
1043 struct zone
*zone_for_pfn_range(int online_type
, int nid
,
1044 struct memory_group
*group
, unsigned long start_pfn
,
1045 unsigned long nr_pages
)
1047 if (online_type
== MMOP_ONLINE_KERNEL
)
1048 return default_kernel_zone_for_pfn(nid
, start_pfn
, nr_pages
);
1050 if (online_type
== MMOP_ONLINE_MOVABLE
)
1051 return &NODE_DATA(nid
)->node_zones
[ZONE_MOVABLE
];
1053 if (online_policy
== ONLINE_POLICY_AUTO_MOVABLE
)
1054 return auto_movable_zone_for_pfn(nid
, group
, start_pfn
, nr_pages
);
1056 return default_zone_for_pfn(nid
, start_pfn
, nr_pages
);
1060 * This function should only be called by memory_block_{online,offline},
1061 * and {online,offline}_pages.
1063 void adjust_present_page_count(struct page
*page
, struct memory_group
*group
,
1066 struct zone
*zone
= page_zone(page
);
1067 const bool movable
= zone_idx(zone
) == ZONE_MOVABLE
;
1070 * We only support onlining/offlining/adding/removing of complete
1071 * memory blocks; therefore, either all is either early or hotplugged.
1073 if (early_section(__pfn_to_section(page_to_pfn(page
))))
1074 zone
->present_early_pages
+= nr_pages
;
1075 zone
->present_pages
+= nr_pages
;
1076 zone
->zone_pgdat
->node_present_pages
+= nr_pages
;
1078 if (group
&& movable
)
1079 group
->present_movable_pages
+= nr_pages
;
1080 else if (group
&& !movable
)
1081 group
->present_kernel_pages
+= nr_pages
;
1084 int mhp_init_memmap_on_memory(unsigned long pfn
, unsigned long nr_pages
,
1085 struct zone
*zone
, bool mhp_off_inaccessible
)
1087 unsigned long end_pfn
= pfn
+ nr_pages
;
1090 ret
= kasan_add_zero_shadow(__va(PFN_PHYS(pfn
)), PFN_PHYS(nr_pages
));
1095 * Memory block is accessible at this stage and hence poison the struct
1096 * pages now. If the memory block is accessible during memory hotplug
1097 * addition phase, then page poisining is already performed in
1098 * sparse_add_section().
1100 if (mhp_off_inaccessible
)
1101 page_init_poison(pfn_to_page(pfn
), sizeof(struct page
) * nr_pages
);
1103 move_pfn_range_to_zone(zone
, pfn
, nr_pages
, NULL
, MIGRATE_UNMOVABLE
);
1105 for (i
= 0; i
< nr_pages
; i
++) {
1106 struct page
*page
= pfn_to_page(pfn
+ i
);
1108 __ClearPageOffline(page
);
1109 SetPageVmemmapSelfHosted(page
);
1113 * It might be that the vmemmap_pages fully span sections. If that is
1114 * the case, mark those sections online here as otherwise they will be
1117 if (nr_pages
>= PAGES_PER_SECTION
)
1118 online_mem_sections(pfn
, ALIGN_DOWN(end_pfn
, PAGES_PER_SECTION
));
1123 void mhp_deinit_memmap_on_memory(unsigned long pfn
, unsigned long nr_pages
)
1125 unsigned long end_pfn
= pfn
+ nr_pages
;
1128 * It might be that the vmemmap_pages fully span sections. If that is
1129 * the case, mark those sections offline here as otherwise they will be
1132 if (nr_pages
>= PAGES_PER_SECTION
)
1133 offline_mem_sections(pfn
, ALIGN_DOWN(end_pfn
, PAGES_PER_SECTION
));
1136 * The pages associated with this vmemmap have been offlined, so
1137 * we can reset its state here.
1139 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn
)), pfn
, nr_pages
);
1140 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn
)), PFN_PHYS(nr_pages
));
1144 * Must be called with mem_hotplug_lock in write mode.
1146 int __ref
online_pages(unsigned long pfn
, unsigned long nr_pages
,
1147 struct zone
*zone
, struct memory_group
*group
)
1149 unsigned long flags
;
1150 int need_zonelists_rebuild
= 0;
1151 const int nid
= zone_to_nid(zone
);
1153 struct memory_notify arg
;
1156 * {on,off}lining is constrained to full memory sections (or more
1157 * precisely to memory blocks from the user space POV).
1158 * memmap_on_memory is an exception because it reserves initial part
1159 * of the physical memory space for vmemmaps. That space is pageblock
1162 if (WARN_ON_ONCE(!nr_pages
|| !pageblock_aligned(pfn
) ||
1163 !IS_ALIGNED(pfn
+ nr_pages
, PAGES_PER_SECTION
)))
1167 /* associate pfn range with the zone */
1168 move_pfn_range_to_zone(zone
, pfn
, nr_pages
, NULL
, MIGRATE_ISOLATE
);
1170 arg
.start_pfn
= pfn
;
1171 arg
.nr_pages
= nr_pages
;
1172 node_states_check_changes_online(nr_pages
, zone
, &arg
);
1174 ret
= memory_notify(MEM_GOING_ONLINE
, &arg
);
1175 ret
= notifier_to_errno(ret
);
1177 goto failed_addition
;
1180 * Fixup the number of isolated pageblocks before marking the sections
1181 * onlining, such that undo_isolate_page_range() works correctly.
1183 spin_lock_irqsave(&zone
->lock
, flags
);
1184 zone
->nr_isolate_pageblock
+= nr_pages
/ pageblock_nr_pages
;
1185 spin_unlock_irqrestore(&zone
->lock
, flags
);
1188 * If this zone is not populated, then it is not in zonelist.
1189 * This means the page allocator ignores this zone.
1190 * So, zonelist must be updated after online.
1192 if (!populated_zone(zone
)) {
1193 need_zonelists_rebuild
= 1;
1194 setup_zone_pageset(zone
);
1197 online_pages_range(pfn
, nr_pages
);
1198 adjust_present_page_count(pfn_to_page(pfn
), group
, nr_pages
);
1200 node_states_set_node(nid
, &arg
);
1201 if (need_zonelists_rebuild
)
1202 build_all_zonelists(NULL
);
1204 /* Basic onlining is complete, allow allocation of onlined pages. */
1205 undo_isolate_page_range(pfn
, pfn
+ nr_pages
, MIGRATE_MOVABLE
);
1208 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to
1209 * the tail of the freelist when undoing isolation). Shuffle the whole
1210 * zone to make sure the just onlined pages are properly distributed
1211 * across the whole freelist - to create an initial shuffle.
1215 /* reinitialise watermarks and update pcp limits */
1216 init_per_zone_wmark_min();
1221 writeback_set_ratelimit();
1223 memory_notify(MEM_ONLINE
, &arg
);
1227 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
1228 (unsigned long long) pfn
<< PAGE_SHIFT
,
1229 (((unsigned long long) pfn
+ nr_pages
) << PAGE_SHIFT
) - 1);
1230 memory_notify(MEM_CANCEL_ONLINE
, &arg
);
1231 remove_pfn_range_from_zone(zone
, pfn
, nr_pages
);
1235 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1236 static pg_data_t __ref
*hotadd_init_pgdat(int nid
)
1238 struct pglist_data
*pgdat
;
1241 * NODE_DATA is preallocated (free_area_init) but its internal
1242 * state is not allocated completely. Add missing pieces.
1243 * Completely offline nodes stay around and they just need
1246 pgdat
= NODE_DATA(nid
);
1248 /* init node's zones as empty zones, we don't have any present pages.*/
1249 free_area_init_core_hotplug(pgdat
);
1252 * The node we allocated has no zone fallback lists. For avoiding
1253 * to access not-initialized zonelist, build here.
1255 build_all_zonelists(pgdat
);
1261 * __try_online_node - online a node if offlined
1263 * @set_node_online: Whether we want to online the node
1264 * called by cpu_up() to online a node without onlined memory.
1267 * 1 -> a new node has been allocated
1268 * 0 -> the node is already online
1269 * -ENOMEM -> the node could not be allocated
1271 static int __try_online_node(int nid
, bool set_node_online
)
1276 if (node_online(nid
))
1279 pgdat
= hotadd_init_pgdat(nid
);
1281 pr_err("Cannot online node %d due to NULL pgdat\n", nid
);
1286 if (set_node_online
) {
1287 node_set_online(nid
);
1288 ret
= register_one_node(nid
);
1296 * Users of this function always want to online/register the node
1298 int try_online_node(int nid
)
1302 mem_hotplug_begin();
1303 ret
= __try_online_node(nid
, true);
1308 static int check_hotplug_memory_range(u64 start
, u64 size
)
1310 /* memory range must be block size aligned */
1311 if (!size
|| !IS_ALIGNED(start
, memory_block_size_bytes()) ||
1312 !IS_ALIGNED(size
, memory_block_size_bytes())) {
1313 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1314 memory_block_size_bytes(), start
, size
);
1321 static int online_memory_block(struct memory_block
*mem
, void *arg
)
1323 mem
->online_type
= mhp_default_online_type
;
1324 return device_online(&mem
->dev
);
1327 #ifndef arch_supports_memmap_on_memory
1328 static inline bool arch_supports_memmap_on_memory(unsigned long vmemmap_size
)
1331 * As default, we want the vmemmap to span a complete PMD such that we
1332 * can map the vmemmap using a single PMD if supported by the
1335 return IS_ALIGNED(vmemmap_size
, PMD_SIZE
);
1339 bool mhp_supports_memmap_on_memory(void)
1341 unsigned long vmemmap_size
= memory_block_memmap_size();
1342 unsigned long memmap_pages
= memory_block_memmap_on_memory_pages();
1345 * Besides having arch support and the feature enabled at runtime, we
1346 * need a few more assumptions to hold true:
1348 * a) The vmemmap pages span complete PMDs: We don't want vmemmap code
1349 * to populate memory from the altmap for unrelated parts (i.e.,
1350 * other memory blocks)
1352 * b) The vmemmap pages (and thereby the pages that will be exposed to
1353 * the buddy) have to cover full pageblocks: memory onlining/offlining
1354 * code requires applicable ranges to be page-aligned, for example, to
1355 * set the migratetypes properly.
1357 * TODO: Although we have a check here to make sure that vmemmap pages
1358 * fully populate a PMD, it is not the right place to check for
1359 * this. A much better solution involves improving vmemmap code
1360 * to fallback to base pages when trying to populate vmemmap using
1361 * altmap as an alternative source of memory, and we do not exactly
1362 * populate a single PMD.
1364 if (!mhp_memmap_on_memory())
1368 * Make sure the vmemmap allocation is fully contained
1369 * so that we always allocate vmemmap memory from altmap area.
1371 if (!IS_ALIGNED(vmemmap_size
, PAGE_SIZE
))
1375 * start pfn should be pageblock_nr_pages aligned for correctly
1376 * setting migrate types
1378 if (!pageblock_aligned(memmap_pages
))
1381 if (memmap_pages
== PHYS_PFN(memory_block_size_bytes()))
1382 /* No effective hotplugged memory doesn't make sense. */
1385 return arch_supports_memmap_on_memory(vmemmap_size
);
1387 EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory
);
1389 static void __ref
remove_memory_blocks_and_altmaps(u64 start
, u64 size
)
1391 unsigned long memblock_size
= memory_block_size_bytes();
1395 * For memmap_on_memory, the altmaps were added on a per-memblock
1396 * basis; we have to process each individual memory block.
1398 for (cur_start
= start
; cur_start
< start
+ size
;
1399 cur_start
+= memblock_size
) {
1400 struct vmem_altmap
*altmap
= NULL
;
1401 struct memory_block
*mem
;
1403 mem
= find_memory_block(pfn_to_section_nr(PFN_DOWN(cur_start
)));
1404 if (WARN_ON_ONCE(!mem
))
1407 altmap
= mem
->altmap
;
1410 remove_memory_block_devices(cur_start
, memblock_size
);
1412 arch_remove_memory(cur_start
, memblock_size
, altmap
);
1414 /* Verify that all vmemmap pages have actually been freed. */
1415 WARN(altmap
->alloc
, "Altmap not fully unmapped");
1420 static int create_altmaps_and_memory_blocks(int nid
, struct memory_group
*group
,
1421 u64 start
, u64 size
, mhp_t mhp_flags
)
1423 unsigned long memblock_size
= memory_block_size_bytes();
1427 for (cur_start
= start
; cur_start
< start
+ size
;
1428 cur_start
+= memblock_size
) {
1429 struct mhp_params params
= { .pgprot
=
1430 pgprot_mhp(PAGE_KERNEL
) };
1431 struct vmem_altmap mhp_altmap
= {
1432 .base_pfn
= PHYS_PFN(cur_start
),
1433 .end_pfn
= PHYS_PFN(cur_start
+ memblock_size
- 1),
1436 mhp_altmap
.free
= memory_block_memmap_on_memory_pages();
1437 if (mhp_flags
& MHP_OFFLINE_INACCESSIBLE
)
1438 mhp_altmap
.inaccessible
= true;
1439 params
.altmap
= kmemdup(&mhp_altmap
, sizeof(struct vmem_altmap
),
1441 if (!params
.altmap
) {
1446 /* call arch's memory hotadd */
1447 ret
= arch_add_memory(nid
, cur_start
, memblock_size
, ¶ms
);
1449 kfree(params
.altmap
);
1453 /* create memory block devices after memory was added */
1454 ret
= create_memory_block_devices(cur_start
, memblock_size
,
1455 params
.altmap
, group
);
1457 arch_remove_memory(cur_start
, memblock_size
, NULL
);
1458 kfree(params
.altmap
);
1465 if (ret
&& cur_start
!= start
)
1466 remove_memory_blocks_and_altmaps(start
, cur_start
- start
);
1471 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1472 * and online/offline operations (triggered e.g. by sysfs).
1474 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1476 int __ref
add_memory_resource(int nid
, struct resource
*res
, mhp_t mhp_flags
)
1478 struct mhp_params params
= { .pgprot
= pgprot_mhp(PAGE_KERNEL
) };
1479 enum memblock_flags memblock_flags
= MEMBLOCK_NONE
;
1480 struct memory_group
*group
= NULL
;
1482 bool new_node
= false;
1486 size
= resource_size(res
);
1488 ret
= check_hotplug_memory_range(start
, size
);
1492 if (mhp_flags
& MHP_NID_IS_MGID
) {
1493 group
= memory_group_find_by_id(nid
);
1499 if (!node_possible(nid
)) {
1500 WARN(1, "node %d was absent from the node_possible_map\n", nid
);
1504 mem_hotplug_begin();
1506 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK
)) {
1507 if (res
->flags
& IORESOURCE_SYSRAM_DRIVER_MANAGED
)
1508 memblock_flags
= MEMBLOCK_DRIVER_MANAGED
;
1509 ret
= memblock_add_node(start
, size
, nid
, memblock_flags
);
1511 goto error_mem_hotplug_end
;
1514 ret
= __try_online_node(nid
, false);
1520 * Self hosted memmap array
1522 if ((mhp_flags
& MHP_MEMMAP_ON_MEMORY
) &&
1523 mhp_supports_memmap_on_memory()) {
1524 ret
= create_altmaps_and_memory_blocks(nid
, group
, start
, size
, mhp_flags
);
1528 ret
= arch_add_memory(nid
, start
, size
, ¶ms
);
1532 /* create memory block devices after memory was added */
1533 ret
= create_memory_block_devices(start
, size
, NULL
, group
);
1535 arch_remove_memory(start
, size
, params
.altmap
);
1541 /* If sysfs file of new node can't be created, cpu on the node
1542 * can't be hot-added. There is no rollback way now.
1543 * So, check by BUG_ON() to catch it reluctantly..
1544 * We online node here. We can't roll back from here.
1546 node_set_online(nid
);
1547 ret
= __register_one_node(nid
);
1551 register_memory_blocks_under_node(nid
, PFN_DOWN(start
),
1552 PFN_UP(start
+ size
- 1),
1555 /* create new memmap entry */
1556 if (!strcmp(res
->name
, "System RAM"))
1557 firmware_map_add_hotplug(start
, start
+ size
, "System RAM");
1559 /* device_online() will take the lock when calling online_pages() */
1563 * In case we're allowed to merge the resource, flag it and trigger
1564 * merging now that adding succeeded.
1566 if (mhp_flags
& MHP_MERGE_RESOURCE
)
1567 merge_system_ram_resource(res
);
1569 /* online pages if requested */
1570 if (mhp_default_online_type
!= MMOP_OFFLINE
)
1571 walk_memory_blocks(start
, size
, NULL
, online_memory_block
);
1575 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK
))
1576 memblock_remove(start
, size
);
1577 error_mem_hotplug_end
:
1582 /* requires device_hotplug_lock, see add_memory_resource() */
1583 int __ref
__add_memory(int nid
, u64 start
, u64 size
, mhp_t mhp_flags
)
1585 struct resource
*res
;
1588 res
= register_memory_resource(start
, size
, "System RAM");
1590 return PTR_ERR(res
);
1592 ret
= add_memory_resource(nid
, res
, mhp_flags
);
1594 release_memory_resource(res
);
1598 int add_memory(int nid
, u64 start
, u64 size
, mhp_t mhp_flags
)
1602 lock_device_hotplug();
1603 rc
= __add_memory(nid
, start
, size
, mhp_flags
);
1604 unlock_device_hotplug();
1608 EXPORT_SYMBOL_GPL(add_memory
);
1611 * Add special, driver-managed memory to the system as system RAM. Such
1612 * memory is not exposed via the raw firmware-provided memmap as system
1613 * RAM, instead, it is detected and added by a driver - during cold boot,
1614 * after a reboot, and after kexec.
1616 * Reasons why this memory should not be used for the initial memmap of a
1617 * kexec kernel or for placing kexec images:
1618 * - The booting kernel is in charge of determining how this memory will be
1619 * used (e.g., use persistent memory as system RAM)
1620 * - Coordination with a hypervisor is required before this memory
1621 * can be used (e.g., inaccessible parts).
1623 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided
1624 * memory map") are created. Also, the created memory resource is flagged
1625 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case
1626 * this memory as well (esp., not place kexec images onto it).
1628 * The resource_name (visible via /proc/iomem) has to have the format
1629 * "System RAM ($DRIVER)".
1631 int add_memory_driver_managed(int nid
, u64 start
, u64 size
,
1632 const char *resource_name
, mhp_t mhp_flags
)
1634 struct resource
*res
;
1637 if (!resource_name
||
1638 strstr(resource_name
, "System RAM (") != resource_name
||
1639 resource_name
[strlen(resource_name
) - 1] != ')')
1642 lock_device_hotplug();
1644 res
= register_memory_resource(start
, size
, resource_name
);
1650 rc
= add_memory_resource(nid
, res
, mhp_flags
);
1652 release_memory_resource(res
);
1655 unlock_device_hotplug();
1658 EXPORT_SYMBOL_GPL(add_memory_driver_managed
);
1661 * Platforms should define arch_get_mappable_range() that provides
1662 * maximum possible addressable physical memory range for which the
1663 * linear mapping could be created. The platform returned address
1664 * range must adhere to these following semantics.
1666 * - range.start <= range.end
1667 * - Range includes both end points [range.start..range.end]
1669 * There is also a fallback definition provided here, allowing the
1670 * entire possible physical address range in case any platform does
1671 * not define arch_get_mappable_range().
1673 struct range __weak
arch_get_mappable_range(void)
1675 struct range mhp_range
= {
1682 struct range
mhp_get_pluggable_range(bool need_mapping
)
1684 const u64 max_phys
= (1ULL << MAX_PHYSMEM_BITS
) - 1;
1685 struct range mhp_range
;
1688 mhp_range
= arch_get_mappable_range();
1689 if (mhp_range
.start
> max_phys
) {
1690 mhp_range
.start
= 0;
1693 mhp_range
.end
= min_t(u64
, mhp_range
.end
, max_phys
);
1695 mhp_range
.start
= 0;
1696 mhp_range
.end
= max_phys
;
1700 EXPORT_SYMBOL_GPL(mhp_get_pluggable_range
);
1702 bool mhp_range_allowed(u64 start
, u64 size
, bool need_mapping
)
1704 struct range mhp_range
= mhp_get_pluggable_range(need_mapping
);
1705 u64 end
= start
+ size
;
1707 if (start
< end
&& start
>= mhp_range
.start
&& (end
- 1) <= mhp_range
.end
)
1710 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n",
1711 start
, end
, mhp_range
.start
, mhp_range
.end
);
1715 #ifdef CONFIG_MEMORY_HOTREMOVE
1717 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1718 * non-lru movable pages and hugepages). Will skip over most unmovable
1719 * pages (esp., pages that can be skipped when offlining), but bail out on
1720 * definitely unmovable pages.
1723 * 0 in case a movable page is found and movable_pfn was updated.
1724 * -ENOENT in case no movable page was found.
1725 * -EBUSY in case a definitely unmovable page was found.
1727 static int scan_movable_pages(unsigned long start
, unsigned long end
,
1728 unsigned long *movable_pfn
)
1732 for (pfn
= start
; pfn
< end
; pfn
++) {
1734 struct folio
*folio
;
1736 if (!pfn_valid(pfn
))
1738 page
= pfn_to_page(pfn
);
1741 if (__PageMovable(page
))
1745 * PageOffline() pages that are not marked __PageMovable() and
1746 * have a reference count > 0 (after MEM_GOING_OFFLINE) are
1747 * definitely unmovable. If their reference count would be 0,
1748 * they could at least be skipped when offlining memory.
1750 if (PageOffline(page
) && page_count(page
))
1753 if (!PageHuge(page
))
1755 folio
= page_folio(page
);
1757 * This test is racy as we hold no reference or lock. The
1758 * hugetlb page could have been free'ed and head is no longer
1759 * a hugetlb page before the following check. In such unlikely
1760 * cases false positives and negatives are possible. Calling
1761 * code must deal with these scenarios.
1763 if (folio_test_hugetlb_migratable(folio
))
1765 pfn
|= folio_nr_pages(folio
) - 1;
1773 static void do_migrate_range(unsigned long start_pfn
, unsigned long end_pfn
)
1776 struct page
*page
, *head
;
1778 static DEFINE_RATELIMIT_STATE(migrate_rs
, DEFAULT_RATELIMIT_INTERVAL
,
1779 DEFAULT_RATELIMIT_BURST
);
1781 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
++) {
1782 struct folio
*folio
;
1785 if (!pfn_valid(pfn
))
1787 page
= pfn_to_page(pfn
);
1788 folio
= page_folio(page
);
1789 head
= &folio
->page
;
1791 if (PageHuge(page
)) {
1792 pfn
= page_to_pfn(head
) + compound_nr(head
) - 1;
1793 isolate_hugetlb(folio
, &source
);
1795 } else if (PageTransHuge(page
))
1796 pfn
= page_to_pfn(head
) + thp_nr_pages(page
) - 1;
1799 * HWPoison pages have elevated reference counts so the migration would
1800 * fail on them. It also doesn't make any sense to migrate them in the
1801 * first place. Still try to unmap such a page in case it is still mapped
1802 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1803 * the unmap as the catch all safety net).
1805 if (PageHWPoison(page
)) {
1806 if (WARN_ON(folio_test_lru(folio
)))
1807 folio_isolate_lru(folio
);
1808 if (folio_mapped(folio
))
1809 try_to_unmap(folio
, TTU_IGNORE_MLOCK
);
1813 if (!get_page_unless_zero(page
))
1816 * We can skip free pages. And we can deal with pages on
1817 * LRU and non-lru movable pages.
1820 isolated
= isolate_lru_page(page
);
1822 isolated
= isolate_movable_page(page
, ISOLATE_UNEVICTABLE
);
1824 list_add_tail(&page
->lru
, &source
);
1825 if (!__PageMovable(page
))
1826 inc_node_page_state(page
, NR_ISOLATED_ANON
+
1827 page_is_file_lru(page
));
1830 if (__ratelimit(&migrate_rs
)) {
1831 pr_warn("failed to isolate pfn %lx\n", pfn
);
1832 dump_page(page
, "isolation failed");
1837 if (!list_empty(&source
)) {
1838 nodemask_t nmask
= node_states
[N_MEMORY
];
1839 struct migration_target_control mtc
= {
1841 .gfp_mask
= GFP_USER
| __GFP_MOVABLE
| __GFP_RETRY_MAYFAIL
,
1842 .reason
= MR_MEMORY_HOTPLUG
,
1847 * We have checked that migration range is on a single zone so
1848 * we can use the nid of the first page to all the others.
1850 mtc
.nid
= page_to_nid(list_first_entry(&source
, struct page
, lru
));
1853 * try to allocate from a different node but reuse this node
1854 * if there are no other online nodes to be used (e.g. we are
1855 * offlining a part of the only existing node)
1857 node_clear(mtc
.nid
, nmask
);
1858 if (nodes_empty(nmask
))
1859 node_set(mtc
.nid
, nmask
);
1860 ret
= migrate_pages(&source
, alloc_migration_target
, NULL
,
1861 (unsigned long)&mtc
, MIGRATE_SYNC
, MR_MEMORY_HOTPLUG
, NULL
);
1863 list_for_each_entry(page
, &source
, lru
) {
1864 if (__ratelimit(&migrate_rs
)) {
1865 pr_warn("migrating pfn %lx failed ret:%d\n",
1866 page_to_pfn(page
), ret
);
1867 dump_page(page
, "migration failure");
1870 putback_movable_pages(&source
);
1875 static int __init
cmdline_parse_movable_node(char *p
)
1877 movable_node_enabled
= true;
1880 early_param("movable_node", cmdline_parse_movable_node
);
1882 /* check which state of node_states will be changed when offline memory */
1883 static void node_states_check_changes_offline(unsigned long nr_pages
,
1884 struct zone
*zone
, struct memory_notify
*arg
)
1886 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
1887 unsigned long present_pages
= 0;
1890 arg
->status_change_nid
= NUMA_NO_NODE
;
1891 arg
->status_change_nid_normal
= NUMA_NO_NODE
;
1894 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1895 * If the memory to be offline is within the range
1896 * [0..ZONE_NORMAL], and it is the last present memory there,
1897 * the zones in that range will become empty after the offlining,
1898 * thus we can determine that we need to clear the node from
1899 * node_states[N_NORMAL_MEMORY].
1901 for (zt
= 0; zt
<= ZONE_NORMAL
; zt
++)
1902 present_pages
+= pgdat
->node_zones
[zt
].present_pages
;
1903 if (zone_idx(zone
) <= ZONE_NORMAL
&& nr_pages
>= present_pages
)
1904 arg
->status_change_nid_normal
= zone_to_nid(zone
);
1907 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
1908 * does not apply as we don't support 32bit.
1909 * Here we count the possible pages from ZONE_MOVABLE.
1910 * If after having accounted all the pages, we see that the nr_pages
1911 * to be offlined is over or equal to the accounted pages,
1912 * we know that the node will become empty, and so, we can clear
1913 * it for N_MEMORY as well.
1915 present_pages
+= pgdat
->node_zones
[ZONE_MOVABLE
].present_pages
;
1917 if (nr_pages
>= present_pages
)
1918 arg
->status_change_nid
= zone_to_nid(zone
);
1921 static void node_states_clear_node(int node
, struct memory_notify
*arg
)
1923 if (arg
->status_change_nid_normal
>= 0)
1924 node_clear_state(node
, N_NORMAL_MEMORY
);
1926 if (arg
->status_change_nid
>= 0)
1927 node_clear_state(node
, N_MEMORY
);
1930 static int count_system_ram_pages_cb(unsigned long start_pfn
,
1931 unsigned long nr_pages
, void *data
)
1933 unsigned long *nr_system_ram_pages
= data
;
1935 *nr_system_ram_pages
+= nr_pages
;
1940 * Must be called with mem_hotplug_lock in write mode.
1942 int __ref
offline_pages(unsigned long start_pfn
, unsigned long nr_pages
,
1943 struct zone
*zone
, struct memory_group
*group
)
1945 const unsigned long end_pfn
= start_pfn
+ nr_pages
;
1946 unsigned long pfn
, managed_pages
, system_ram_pages
= 0;
1947 const int node
= zone_to_nid(zone
);
1948 unsigned long flags
;
1949 struct memory_notify arg
;
1954 * {on,off}lining is constrained to full memory sections (or more
1955 * precisely to memory blocks from the user space POV).
1956 * memmap_on_memory is an exception because it reserves initial part
1957 * of the physical memory space for vmemmaps. That space is pageblock
1960 if (WARN_ON_ONCE(!nr_pages
|| !pageblock_aligned(start_pfn
) ||
1961 !IS_ALIGNED(start_pfn
+ nr_pages
, PAGES_PER_SECTION
)))
1965 * Don't allow to offline memory blocks that contain holes.
1966 * Consequently, memory blocks with holes can never get onlined
1967 * via the hotplug path - online_pages() - as hotplugged memory has
1968 * no holes. This way, we don't have to worry about memory holes,
1969 * don't need pfn_valid() checks, and can avoid using
1970 * walk_system_ram_range() later.
1972 walk_system_ram_range(start_pfn
, nr_pages
, &system_ram_pages
,
1973 count_system_ram_pages_cb
);
1974 if (system_ram_pages
!= nr_pages
) {
1976 reason
= "memory holes";
1977 goto failed_removal
;
1981 * We only support offlining of memory blocks managed by a single zone,
1982 * checked by calling code. This is just a sanity check that we might
1983 * want to remove in the future.
1985 if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn
)) != zone
||
1986 page_zone(pfn_to_page(end_pfn
- 1)) != zone
)) {
1988 reason
= "multizone range";
1989 goto failed_removal
;
1993 * Disable pcplists so that page isolation cannot race with freeing
1994 * in a way that pages from isolated pageblock are left on pcplists.
1996 zone_pcp_disable(zone
);
1997 lru_cache_disable();
1999 /* set above range as isolated */
2000 ret
= start_isolate_page_range(start_pfn
, end_pfn
,
2002 MEMORY_OFFLINE
| REPORT_FAILURE
,
2003 GFP_USER
| __GFP_MOVABLE
| __GFP_RETRY_MAYFAIL
);
2005 reason
= "failure to isolate range";
2006 goto failed_removal_pcplists_disabled
;
2009 arg
.start_pfn
= start_pfn
;
2010 arg
.nr_pages
= nr_pages
;
2011 node_states_check_changes_offline(nr_pages
, zone
, &arg
);
2013 ret
= memory_notify(MEM_GOING_OFFLINE
, &arg
);
2014 ret
= notifier_to_errno(ret
);
2016 reason
= "notifier failure";
2017 goto failed_removal_isolated
;
2024 * Historically we always checked for any signal and
2025 * can't limit it to fatal signals without eventually
2026 * breaking user space.
2028 if (signal_pending(current
)) {
2030 reason
= "signal backoff";
2031 goto failed_removal_isolated
;
2036 ret
= scan_movable_pages(pfn
, end_pfn
, &pfn
);
2039 * TODO: fatal migration failures should bail
2042 do_migrate_range(pfn
, end_pfn
);
2046 if (ret
!= -ENOENT
) {
2047 reason
= "unmovable page";
2048 goto failed_removal_isolated
;
2052 * Dissolve free hugetlb folios in the memory block before doing
2053 * offlining actually in order to make hugetlbfs's object
2054 * counting consistent.
2056 ret
= dissolve_free_hugetlb_folios(start_pfn
, end_pfn
);
2058 reason
= "failure to dissolve huge pages";
2059 goto failed_removal_isolated
;
2062 ret
= test_pages_isolated(start_pfn
, end_pfn
, MEMORY_OFFLINE
);
2066 /* Mark all sections offline and remove free pages from the buddy. */
2067 managed_pages
= __offline_isolated_pages(start_pfn
, end_pfn
);
2068 pr_debug("Offlined Pages %ld\n", nr_pages
);
2071 * The memory sections are marked offline, and the pageblock flags
2072 * effectively stale; nobody should be touching them. Fixup the number
2073 * of isolated pageblocks, memory onlining will properly revert this.
2075 spin_lock_irqsave(&zone
->lock
, flags
);
2076 zone
->nr_isolate_pageblock
-= nr_pages
/ pageblock_nr_pages
;
2077 spin_unlock_irqrestore(&zone
->lock
, flags
);
2080 zone_pcp_enable(zone
);
2082 /* removal success */
2083 adjust_managed_page_count(pfn_to_page(start_pfn
), -managed_pages
);
2084 adjust_present_page_count(pfn_to_page(start_pfn
), group
, -nr_pages
);
2086 /* reinitialise watermarks and update pcp limits */
2087 init_per_zone_wmark_min();
2090 * Make sure to mark the node as memory-less before rebuilding the zone
2091 * list. Otherwise this node would still appear in the fallback lists.
2093 node_states_clear_node(node
, &arg
);
2094 if (!populated_zone(zone
)) {
2095 zone_pcp_reset(zone
);
2096 build_all_zonelists(NULL
);
2099 if (arg
.status_change_nid
>= 0) {
2100 kcompactd_stop(node
);
2104 writeback_set_ratelimit();
2106 memory_notify(MEM_OFFLINE
, &arg
);
2107 remove_pfn_range_from_zone(zone
, start_pfn
, nr_pages
);
2110 failed_removal_isolated
:
2111 /* pushback to free area */
2112 undo_isolate_page_range(start_pfn
, end_pfn
, MIGRATE_MOVABLE
);
2113 memory_notify(MEM_CANCEL_OFFLINE
, &arg
);
2114 failed_removal_pcplists_disabled
:
2116 zone_pcp_enable(zone
);
2118 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
2119 (unsigned long long) start_pfn
<< PAGE_SHIFT
,
2120 ((unsigned long long) end_pfn
<< PAGE_SHIFT
) - 1,
2125 static int check_memblock_offlined_cb(struct memory_block
*mem
, void *arg
)
2130 if (unlikely(mem
->state
!= MEM_OFFLINE
)) {
2131 phys_addr_t beginpa
, endpa
;
2133 beginpa
= PFN_PHYS(section_nr_to_pfn(mem
->start_section_nr
));
2134 endpa
= beginpa
+ memory_block_size_bytes() - 1;
2135 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
2143 static int count_memory_range_altmaps_cb(struct memory_block
*mem
, void *arg
)
2145 u64
*num_altmaps
= (u64
*)arg
;
2153 static int check_cpu_on_node(int nid
)
2157 for_each_present_cpu(cpu
) {
2158 if (cpu_to_node(cpu
) == nid
)
2160 * the cpu on this node isn't removed, and we can't
2161 * offline this node.
2169 static int check_no_memblock_for_node_cb(struct memory_block
*mem
, void *arg
)
2171 int nid
= *(int *)arg
;
2174 * If a memory block belongs to multiple nodes, the stored nid is not
2175 * reliable. However, such blocks are always online (e.g., cannot get
2176 * offlined) and, therefore, are still spanned by the node.
2178 return mem
->nid
== nid
? -EEXIST
: 0;
2185 * Offline a node if all memory sections and cpus of the node are removed.
2187 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2188 * and online/offline operations before this call.
2190 void try_offline_node(int nid
)
2195 * If the node still spans pages (especially ZONE_DEVICE), don't
2196 * offline it. A node spans memory after move_pfn_range_to_zone(),
2197 * e.g., after the memory block was onlined.
2199 if (node_spanned_pages(nid
))
2203 * Especially offline memory blocks might not be spanned by the
2204 * node. They will get spanned by the node once they get onlined.
2205 * However, they link to the node in sysfs and can get onlined later.
2207 rc
= for_each_memory_block(&nid
, check_no_memblock_for_node_cb
);
2211 if (check_cpu_on_node(nid
))
2215 * all memory/cpu of this node are removed, we can offline this
2218 node_set_offline(nid
);
2219 unregister_one_node(nid
);
2221 EXPORT_SYMBOL(try_offline_node
);
2223 static int memory_blocks_have_altmaps(u64 start
, u64 size
)
2225 u64 num_memblocks
= size
/ memory_block_size_bytes();
2226 u64 num_altmaps
= 0;
2228 if (!mhp_memmap_on_memory())
2231 walk_memory_blocks(start
, size
, &num_altmaps
,
2232 count_memory_range_altmaps_cb
);
2234 if (num_altmaps
== 0)
2237 if (WARN_ON_ONCE(num_memblocks
!= num_altmaps
))
2243 static int __ref
try_remove_memory(u64 start
, u64 size
)
2245 int rc
, nid
= NUMA_NO_NODE
;
2247 BUG_ON(check_hotplug_memory_range(start
, size
));
2250 * All memory blocks must be offlined before removing memory. Check
2251 * whether all memory blocks in question are offline and return error
2252 * if this is not the case.
2254 * While at it, determine the nid. Note that if we'd have mixed nodes,
2255 * we'd only try to offline the last determined one -- which is good
2256 * enough for the cases we care about.
2258 rc
= walk_memory_blocks(start
, size
, &nid
, check_memblock_offlined_cb
);
2262 /* remove memmap entry */
2263 firmware_map_remove(start
, start
+ size
, "System RAM");
2265 mem_hotplug_begin();
2267 rc
= memory_blocks_have_altmaps(start
, size
);
2273 * Memory block device removal under the device_hotplug_lock is
2274 * a barrier against racing online attempts.
2275 * No altmaps present, do the removal directly
2277 remove_memory_block_devices(start
, size
);
2278 arch_remove_memory(start
, size
, NULL
);
2280 /* all memblocks in the range have altmaps */
2281 remove_memory_blocks_and_altmaps(start
, size
);
2284 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK
))
2285 memblock_remove(start
, size
);
2287 release_mem_region_adjustable(start
, size
);
2289 if (nid
!= NUMA_NO_NODE
)
2290 try_offline_node(nid
);
2297 * __remove_memory - Remove memory if every memory block is offline
2298 * @start: physical address of the region to remove
2299 * @size: size of the region to remove
2301 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2302 * and online/offline operations before this call, as required by
2303 * try_offline_node().
2305 void __remove_memory(u64 start
, u64 size
)
2309 * trigger BUG() if some memory is not offlined prior to calling this
2312 if (try_remove_memory(start
, size
))
2317 * Remove memory if every memory block is offline, otherwise return -EBUSY is
2318 * some memory is not offline
2320 int remove_memory(u64 start
, u64 size
)
2324 lock_device_hotplug();
2325 rc
= try_remove_memory(start
, size
);
2326 unlock_device_hotplug();
2330 EXPORT_SYMBOL_GPL(remove_memory
);
2332 static int try_offline_memory_block(struct memory_block
*mem
, void *arg
)
2334 uint8_t online_type
= MMOP_ONLINE_KERNEL
;
2335 uint8_t **online_types
= arg
;
2340 * Sense the online_type via the zone of the memory block. Offlining
2341 * with multiple zones within one memory block will be rejected
2342 * by offlining code ... so we don't care about that.
2344 page
= pfn_to_online_page(section_nr_to_pfn(mem
->start_section_nr
));
2345 if (page
&& zone_idx(page_zone(page
)) == ZONE_MOVABLE
)
2346 online_type
= MMOP_ONLINE_MOVABLE
;
2348 rc
= device_offline(&mem
->dev
);
2350 * Default is MMOP_OFFLINE - change it only if offlining succeeded,
2351 * so try_reonline_memory_block() can do the right thing.
2354 **online_types
= online_type
;
2357 /* Ignore if already offline. */
2358 return rc
< 0 ? rc
: 0;
2361 static int try_reonline_memory_block(struct memory_block
*mem
, void *arg
)
2363 uint8_t **online_types
= arg
;
2366 if (**online_types
!= MMOP_OFFLINE
) {
2367 mem
->online_type
= **online_types
;
2368 rc
= device_online(&mem
->dev
);
2370 pr_warn("%s: Failed to re-online memory: %d",
2374 /* Continue processing all remaining memory blocks. */
2380 * Try to offline and remove memory. Might take a long time to finish in case
2381 * memory is still in use. Primarily useful for memory devices that logically
2382 * unplugged all memory (so it's no longer in use) and want to offline + remove
2385 int offline_and_remove_memory(u64 start
, u64 size
)
2387 const unsigned long mb_count
= size
/ memory_block_size_bytes();
2388 uint8_t *online_types
, *tmp
;
2391 if (!IS_ALIGNED(start
, memory_block_size_bytes()) ||
2392 !IS_ALIGNED(size
, memory_block_size_bytes()) || !size
)
2396 * We'll remember the old online type of each memory block, so we can
2397 * try to revert whatever we did when offlining one memory block fails
2398 * after offlining some others succeeded.
2400 online_types
= kmalloc_array(mb_count
, sizeof(*online_types
),
2405 * Initialize all states to MMOP_OFFLINE, so when we abort processing in
2406 * try_offline_memory_block(), we'll skip all unprocessed blocks in
2407 * try_reonline_memory_block().
2409 memset(online_types
, MMOP_OFFLINE
, mb_count
);
2411 lock_device_hotplug();
2414 rc
= walk_memory_blocks(start
, size
, &tmp
, try_offline_memory_block
);
2417 * In case we succeeded to offline all memory, remove it.
2418 * This cannot fail as it cannot get onlined in the meantime.
2421 rc
= try_remove_memory(start
, size
);
2423 pr_err("%s: Failed to remove memory: %d", __func__
, rc
);
2427 * Rollback what we did. While memory onlining might theoretically fail
2428 * (nacked by a notifier), it barely ever happens.
2432 walk_memory_blocks(start
, size
, &tmp
,
2433 try_reonline_memory_block
);
2435 unlock_device_hotplug();
2437 kfree(online_types
);
2440 EXPORT_SYMBOL_GPL(offline_and_remove_memory
);
2441 #endif /* CONFIG_MEMORY_HOTREMOVE */