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/pagevec.h>
17 #include <linux/writeback.h>
18 #include <linux/slab.h>
19 #include <linux/sysctl.h>
20 #include <linux/cpu.h>
21 #include <linux/memory.h>
22 #include <linux/memremap.h>
23 #include <linux/memory_hotplug.h>
24 #include <linux/vmalloc.h>
25 #include <linux/ioport.h>
26 #include <linux/delay.h>
27 #include <linux/migrate.h>
28 #include <linux/page-isolation.h>
29 #include <linux/pfn.h>
30 #include <linux/suspend.h>
31 #include <linux/mm_inline.h>
32 #include <linux/firmware-map.h>
33 #include <linux/stop_machine.h>
34 #include <linux/hugetlb.h>
35 #include <linux/memblock.h>
36 #include <linux/compaction.h>
37 #include <linux/rmap.h>
38 #include <linux/module.h>
40 #include <asm/tlbflush.h>
45 #ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
47 * memory_hotplug.memmap_on_memory parameter
49 static bool memmap_on_memory __ro_after_init
;
50 module_param(memmap_on_memory
, bool, 0444);
51 MODULE_PARM_DESC(memmap_on_memory
, "Enable memmap on memory for memory hotplug");
53 static inline bool mhp_memmap_on_memory(void)
55 return memmap_on_memory
;
58 static inline bool mhp_memmap_on_memory(void)
65 ONLINE_POLICY_CONTIG_ZONES
= 0,
66 ONLINE_POLICY_AUTO_MOVABLE
,
69 static const char * const online_policy_to_str
[] = {
70 [ONLINE_POLICY_CONTIG_ZONES
] = "contig-zones",
71 [ONLINE_POLICY_AUTO_MOVABLE
] = "auto-movable",
74 static int set_online_policy(const char *val
, const struct kernel_param
*kp
)
76 int ret
= sysfs_match_string(online_policy_to_str
, val
);
80 *((int *)kp
->arg
) = ret
;
84 static int get_online_policy(char *buffer
, const struct kernel_param
*kp
)
86 return sprintf(buffer
, "%s\n", online_policy_to_str
[*((int *)kp
->arg
)]);
90 * memory_hotplug.online_policy: configure online behavior when onlining without
91 * specifying a zone (MMOP_ONLINE)
93 * "contig-zones": keep zone contiguous
94 * "auto-movable": online memory to ZONE_MOVABLE if the configuration
95 * (auto_movable_ratio, auto_movable_numa_aware) allows for it
97 static int online_policy __read_mostly
= ONLINE_POLICY_CONTIG_ZONES
;
98 static const struct kernel_param_ops online_policy_ops
= {
99 .set
= set_online_policy
,
100 .get
= get_online_policy
,
102 module_param_cb(online_policy
, &online_policy_ops
, &online_policy
, 0644);
103 MODULE_PARM_DESC(online_policy
,
104 "Set the online policy (\"contig-zones\", \"auto-movable\") "
105 "Default: \"contig-zones\"");
108 * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio
110 * The ratio represent an upper limit and the kernel might decide to not
111 * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory
112 * doesn't allow for more MOVABLE memory.
114 static unsigned int auto_movable_ratio __read_mostly
= 301;
115 module_param(auto_movable_ratio
, uint
, 0644);
116 MODULE_PARM_DESC(auto_movable_ratio
,
117 "Set the maximum ratio of MOVABLE:KERNEL memory in the system "
118 "in percent for \"auto-movable\" online policy. Default: 301");
121 * memory_hotplug.auto_movable_numa_aware: consider numa node stats
124 static bool auto_movable_numa_aware __read_mostly
= true;
125 module_param(auto_movable_numa_aware
, bool, 0644);
126 MODULE_PARM_DESC(auto_movable_numa_aware
,
127 "Consider numa node stats in addition to global stats in "
128 "\"auto-movable\" online policy. Default: true");
129 #endif /* CONFIG_NUMA */
132 * online_page_callback contains pointer to current page onlining function.
133 * Initially it is generic_online_page(). If it is required it could be
134 * changed by calling set_online_page_callback() for callback registration
135 * and restore_online_page_callback() for generic callback restore.
138 static online_page_callback_t online_page_callback
= generic_online_page
;
139 static DEFINE_MUTEX(online_page_callback_lock
);
141 DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock
);
143 void get_online_mems(void)
145 percpu_down_read(&mem_hotplug_lock
);
148 void put_online_mems(void)
150 percpu_up_read(&mem_hotplug_lock
);
153 bool movable_node_enabled
= false;
155 #ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
156 int mhp_default_online_type
= MMOP_OFFLINE
;
158 int mhp_default_online_type
= MMOP_ONLINE
;
161 static int __init
setup_memhp_default_state(char *str
)
163 const int online_type
= mhp_online_type_from_str(str
);
165 if (online_type
>= 0)
166 mhp_default_online_type
= online_type
;
170 __setup("memhp_default_state=", setup_memhp_default_state
);
172 void mem_hotplug_begin(void)
175 percpu_down_write(&mem_hotplug_lock
);
178 void mem_hotplug_done(void)
180 percpu_up_write(&mem_hotplug_lock
);
184 u64 max_mem_size
= U64_MAX
;
186 /* add this memory to iomem resource */
187 static struct resource
*register_memory_resource(u64 start
, u64 size
,
188 const char *resource_name
)
190 struct resource
*res
;
191 unsigned long flags
= IORESOURCE_SYSTEM_RAM
| IORESOURCE_BUSY
;
193 if (strcmp(resource_name
, "System RAM"))
194 flags
|= IORESOURCE_SYSRAM_DRIVER_MANAGED
;
196 if (!mhp_range_allowed(start
, size
, true))
197 return ERR_PTR(-E2BIG
);
200 * Make sure value parsed from 'mem=' only restricts memory adding
201 * while booting, so that memory hotplug won't be impacted. Please
202 * refer to document of 'mem=' in kernel-parameters.txt for more
205 if (start
+ size
> max_mem_size
&& system_state
< SYSTEM_RUNNING
)
206 return ERR_PTR(-E2BIG
);
209 * Request ownership of the new memory range. This might be
210 * a child of an existing resource that was present but
211 * not marked as busy.
213 res
= __request_region(&iomem_resource
, start
, size
,
214 resource_name
, flags
);
217 pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
218 start
, start
+ size
);
219 return ERR_PTR(-EEXIST
);
224 static void release_memory_resource(struct resource
*res
)
228 release_resource(res
);
232 static int check_pfn_span(unsigned long pfn
, unsigned long nr_pages
)
235 * Disallow all operations smaller than a sub-section and only
236 * allow operations smaller than a section for
237 * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
238 * enforces a larger memory_block_size_bytes() granularity for
239 * memory that will be marked online, so this check should only
240 * fire for direct arch_{add,remove}_memory() users outside of
241 * add_memory_resource().
243 unsigned long min_align
;
245 if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP
))
246 min_align
= PAGES_PER_SUBSECTION
;
248 min_align
= PAGES_PER_SECTION
;
249 if (!IS_ALIGNED(pfn
| nr_pages
, min_align
))
255 * Return page for the valid pfn only if the page is online. All pfn
256 * walkers which rely on the fully initialized page->flags and others
257 * should use this rather than pfn_valid && pfn_to_page
259 struct page
*pfn_to_online_page(unsigned long pfn
)
261 unsigned long nr
= pfn_to_section_nr(pfn
);
262 struct dev_pagemap
*pgmap
;
263 struct mem_section
*ms
;
265 if (nr
>= NR_MEM_SECTIONS
)
268 ms
= __nr_to_section(nr
);
269 if (!online_section(ms
))
273 * Save some code text when online_section() +
274 * pfn_section_valid() are sufficient.
276 if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID
) && !pfn_valid(pfn
))
279 if (!pfn_section_valid(ms
, pfn
))
282 if (!online_device_section(ms
))
283 return pfn_to_page(pfn
);
286 * Slowpath: when ZONE_DEVICE collides with
287 * ZONE_{NORMAL,MOVABLE} within the same section some pfns in
288 * the section may be 'offline' but 'valid'. Only
289 * get_dev_pagemap() can determine sub-section online status.
291 pgmap
= get_dev_pagemap(pfn
, NULL
);
292 put_dev_pagemap(pgmap
);
294 /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */
298 return pfn_to_page(pfn
);
300 EXPORT_SYMBOL_GPL(pfn_to_online_page
);
302 int __ref
__add_pages(int nid
, unsigned long pfn
, unsigned long nr_pages
,
303 struct mhp_params
*params
)
305 const unsigned long end_pfn
= pfn
+ nr_pages
;
306 unsigned long cur_nr_pages
;
308 struct vmem_altmap
*altmap
= params
->altmap
;
310 if (WARN_ON_ONCE(!pgprot_val(params
->pgprot
)))
313 VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn
), nr_pages
* PAGE_SIZE
, false));
317 * Validate altmap is within bounds of the total request
319 if (altmap
->base_pfn
!= pfn
320 || vmem_altmap_offset(altmap
) > nr_pages
) {
321 pr_warn_once("memory add fail, invalid altmap\n");
327 if (check_pfn_span(pfn
, nr_pages
)) {
328 WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__
, pfn
, pfn
+ nr_pages
- 1);
332 for (; pfn
< end_pfn
; pfn
+= cur_nr_pages
) {
333 /* Select all remaining pages up to the next section boundary */
334 cur_nr_pages
= min(end_pfn
- pfn
,
335 SECTION_ALIGN_UP(pfn
+ 1) - pfn
);
336 err
= sparse_add_section(nid
, pfn
, cur_nr_pages
, altmap
,
342 vmemmap_populate_print_last();
346 /* find the smallest valid pfn in the range [start_pfn, end_pfn) */
347 static unsigned long find_smallest_section_pfn(int nid
, struct zone
*zone
,
348 unsigned long start_pfn
,
349 unsigned long end_pfn
)
351 for (; start_pfn
< end_pfn
; start_pfn
+= PAGES_PER_SUBSECTION
) {
352 if (unlikely(!pfn_to_online_page(start_pfn
)))
355 if (unlikely(pfn_to_nid(start_pfn
) != nid
))
358 if (zone
!= page_zone(pfn_to_page(start_pfn
)))
367 /* find the biggest valid pfn in the range [start_pfn, end_pfn). */
368 static unsigned long find_biggest_section_pfn(int nid
, struct zone
*zone
,
369 unsigned long start_pfn
,
370 unsigned long end_pfn
)
374 /* pfn is the end pfn of a memory section. */
376 for (; pfn
>= start_pfn
; pfn
-= PAGES_PER_SUBSECTION
) {
377 if (unlikely(!pfn_to_online_page(pfn
)))
380 if (unlikely(pfn_to_nid(pfn
) != nid
))
383 if (zone
!= page_zone(pfn_to_page(pfn
)))
392 static void shrink_zone_span(struct zone
*zone
, unsigned long start_pfn
,
393 unsigned long end_pfn
)
396 int nid
= zone_to_nid(zone
);
398 if (zone
->zone_start_pfn
== start_pfn
) {
400 * If the section is smallest section in the zone, it need
401 * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
402 * In this case, we find second smallest valid mem_section
403 * for shrinking zone.
405 pfn
= find_smallest_section_pfn(nid
, zone
, end_pfn
,
408 zone
->spanned_pages
= zone_end_pfn(zone
) - pfn
;
409 zone
->zone_start_pfn
= pfn
;
411 zone
->zone_start_pfn
= 0;
412 zone
->spanned_pages
= 0;
414 } else if (zone_end_pfn(zone
) == end_pfn
) {
416 * If the section is biggest section in the zone, it need
417 * shrink zone->spanned_pages.
418 * In this case, we find second biggest valid mem_section for
421 pfn
= find_biggest_section_pfn(nid
, zone
, zone
->zone_start_pfn
,
424 zone
->spanned_pages
= pfn
- zone
->zone_start_pfn
+ 1;
426 zone
->zone_start_pfn
= 0;
427 zone
->spanned_pages
= 0;
432 static void update_pgdat_span(struct pglist_data
*pgdat
)
434 unsigned long node_start_pfn
= 0, node_end_pfn
= 0;
437 for (zone
= pgdat
->node_zones
;
438 zone
< pgdat
->node_zones
+ MAX_NR_ZONES
; zone
++) {
439 unsigned long end_pfn
= zone_end_pfn(zone
);
441 /* No need to lock the zones, they can't change. */
442 if (!zone
->spanned_pages
)
445 node_start_pfn
= zone
->zone_start_pfn
;
446 node_end_pfn
= end_pfn
;
450 if (end_pfn
> node_end_pfn
)
451 node_end_pfn
= end_pfn
;
452 if (zone
->zone_start_pfn
< node_start_pfn
)
453 node_start_pfn
= zone
->zone_start_pfn
;
456 pgdat
->node_start_pfn
= node_start_pfn
;
457 pgdat
->node_spanned_pages
= node_end_pfn
- node_start_pfn
;
460 void __ref
remove_pfn_range_from_zone(struct zone
*zone
,
461 unsigned long start_pfn
,
462 unsigned long nr_pages
)
464 const unsigned long end_pfn
= start_pfn
+ nr_pages
;
465 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
466 unsigned long pfn
, cur_nr_pages
;
468 /* Poison struct pages because they are now uninitialized again. */
469 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
+= cur_nr_pages
) {
472 /* Select all remaining pages up to the next section boundary */
474 min(end_pfn
- pfn
, SECTION_ALIGN_UP(pfn
+ 1) - pfn
);
475 page_init_poison(pfn_to_page(pfn
),
476 sizeof(struct page
) * cur_nr_pages
);
480 * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
481 * we will not try to shrink the zones - which is okay as
482 * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
484 if (zone_is_zone_device(zone
))
487 clear_zone_contiguous(zone
);
489 shrink_zone_span(zone
, start_pfn
, start_pfn
+ nr_pages
);
490 update_pgdat_span(pgdat
);
492 set_zone_contiguous(zone
);
495 static void __remove_section(unsigned long pfn
, unsigned long nr_pages
,
496 unsigned long map_offset
,
497 struct vmem_altmap
*altmap
)
499 struct mem_section
*ms
= __pfn_to_section(pfn
);
501 if (WARN_ON_ONCE(!valid_section(ms
)))
504 sparse_remove_section(ms
, pfn
, nr_pages
, map_offset
, altmap
);
508 * __remove_pages() - remove sections of pages
509 * @pfn: starting pageframe (must be aligned to start of a section)
510 * @nr_pages: number of pages to remove (must be multiple of section size)
511 * @altmap: alternative device page map or %NULL if default memmap is used
513 * Generic helper function to remove section mappings and sysfs entries
514 * for the section of the memory we are removing. Caller needs to make
515 * sure that pages are marked reserved and zones are adjust properly by
516 * calling offline_pages().
518 void __remove_pages(unsigned long pfn
, unsigned long nr_pages
,
519 struct vmem_altmap
*altmap
)
521 const unsigned long end_pfn
= pfn
+ nr_pages
;
522 unsigned long cur_nr_pages
;
523 unsigned long map_offset
= 0;
525 map_offset
= vmem_altmap_offset(altmap
);
527 if (check_pfn_span(pfn
, nr_pages
)) {
528 WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__
, pfn
, pfn
+ nr_pages
- 1);
532 for (; pfn
< end_pfn
; pfn
+= cur_nr_pages
) {
534 /* Select all remaining pages up to the next section boundary */
535 cur_nr_pages
= min(end_pfn
- pfn
,
536 SECTION_ALIGN_UP(pfn
+ 1) - pfn
);
537 __remove_section(pfn
, cur_nr_pages
, map_offset
, altmap
);
542 int set_online_page_callback(online_page_callback_t callback
)
547 mutex_lock(&online_page_callback_lock
);
549 if (online_page_callback
== generic_online_page
) {
550 online_page_callback
= callback
;
554 mutex_unlock(&online_page_callback_lock
);
559 EXPORT_SYMBOL_GPL(set_online_page_callback
);
561 int restore_online_page_callback(online_page_callback_t callback
)
566 mutex_lock(&online_page_callback_lock
);
568 if (online_page_callback
== callback
) {
569 online_page_callback
= generic_online_page
;
573 mutex_unlock(&online_page_callback_lock
);
578 EXPORT_SYMBOL_GPL(restore_online_page_callback
);
580 void generic_online_page(struct page
*page
, unsigned int order
)
583 * Freeing the page with debug_pagealloc enabled will try to unmap it,
584 * so we should map it first. This is better than introducing a special
585 * case in page freeing fast path.
587 debug_pagealloc_map_pages(page
, 1 << order
);
588 __free_pages_core(page
, order
);
589 totalram_pages_add(1UL << order
);
591 EXPORT_SYMBOL_GPL(generic_online_page
);
593 static void online_pages_range(unsigned long start_pfn
, unsigned long nr_pages
)
595 const unsigned long end_pfn
= start_pfn
+ nr_pages
;
599 * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might
600 * decide to not expose all pages to the buddy (e.g., expose them
601 * later). We account all pages as being online and belonging to this
603 * When using memmap_on_memory, the range might not be aligned to
604 * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect
605 * this and the first chunk to online will be pageblock_nr_pages.
607 for (pfn
= start_pfn
; pfn
< end_pfn
;) {
608 int order
= min(MAX_ORDER
- 1UL, __ffs(pfn
));
610 (*online_page_callback
)(pfn_to_page(pfn
), order
);
611 pfn
+= (1UL << order
);
614 /* mark all involved sections as online */
615 online_mem_sections(start_pfn
, end_pfn
);
618 /* check which state of node_states will be changed when online memory */
619 static void node_states_check_changes_online(unsigned long nr_pages
,
620 struct zone
*zone
, struct memory_notify
*arg
)
622 int nid
= zone_to_nid(zone
);
624 arg
->status_change_nid
= NUMA_NO_NODE
;
625 arg
->status_change_nid_normal
= NUMA_NO_NODE
;
627 if (!node_state(nid
, N_MEMORY
))
628 arg
->status_change_nid
= nid
;
629 if (zone_idx(zone
) <= ZONE_NORMAL
&& !node_state(nid
, N_NORMAL_MEMORY
))
630 arg
->status_change_nid_normal
= nid
;
633 static void node_states_set_node(int node
, struct memory_notify
*arg
)
635 if (arg
->status_change_nid_normal
>= 0)
636 node_set_state(node
, N_NORMAL_MEMORY
);
638 if (arg
->status_change_nid
>= 0)
639 node_set_state(node
, N_MEMORY
);
642 static void __meminit
resize_zone_range(struct zone
*zone
, unsigned long start_pfn
,
643 unsigned long nr_pages
)
645 unsigned long old_end_pfn
= zone_end_pfn(zone
);
647 if (zone_is_empty(zone
) || start_pfn
< zone
->zone_start_pfn
)
648 zone
->zone_start_pfn
= start_pfn
;
650 zone
->spanned_pages
= max(start_pfn
+ nr_pages
, old_end_pfn
) - zone
->zone_start_pfn
;
653 static void __meminit
resize_pgdat_range(struct pglist_data
*pgdat
, unsigned long start_pfn
,
654 unsigned long nr_pages
)
656 unsigned long old_end_pfn
= pgdat_end_pfn(pgdat
);
658 if (!pgdat
->node_spanned_pages
|| start_pfn
< pgdat
->node_start_pfn
)
659 pgdat
->node_start_pfn
= start_pfn
;
661 pgdat
->node_spanned_pages
= max(start_pfn
+ nr_pages
, old_end_pfn
) - pgdat
->node_start_pfn
;
665 #ifdef CONFIG_ZONE_DEVICE
666 static void section_taint_zone_device(unsigned long pfn
)
668 struct mem_section
*ms
= __pfn_to_section(pfn
);
670 ms
->section_mem_map
|= SECTION_TAINT_ZONE_DEVICE
;
673 static inline void section_taint_zone_device(unsigned long pfn
)
679 * Associate the pfn range with the given zone, initializing the memmaps
680 * and resizing the pgdat/zone data to span the added pages. After this
681 * call, all affected pages are PG_reserved.
683 * All aligned pageblocks are initialized to the specified migratetype
684 * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
685 * zone stats (e.g., nr_isolate_pageblock) are touched.
687 void __ref
move_pfn_range_to_zone(struct zone
*zone
, unsigned long start_pfn
,
688 unsigned long nr_pages
,
689 struct vmem_altmap
*altmap
, int migratetype
)
691 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
692 int nid
= pgdat
->node_id
;
694 clear_zone_contiguous(zone
);
696 if (zone_is_empty(zone
))
697 init_currently_empty_zone(zone
, start_pfn
, nr_pages
);
698 resize_zone_range(zone
, start_pfn
, nr_pages
);
699 resize_pgdat_range(pgdat
, start_pfn
, nr_pages
);
702 * Subsection population requires care in pfn_to_online_page().
703 * Set the taint to enable the slow path detection of
704 * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE}
707 if (zone_is_zone_device(zone
)) {
708 if (!IS_ALIGNED(start_pfn
, PAGES_PER_SECTION
))
709 section_taint_zone_device(start_pfn
);
710 if (!IS_ALIGNED(start_pfn
+ nr_pages
, PAGES_PER_SECTION
))
711 section_taint_zone_device(start_pfn
+ nr_pages
);
715 * TODO now we have a visible range of pages which are not associated
716 * with their zone properly. Not nice but set_pfnblock_flags_mask
717 * expects the zone spans the pfn range. All the pages in the range
718 * are reserved so nobody should be touching them so we should be safe
720 memmap_init_range(nr_pages
, nid
, zone_idx(zone
), start_pfn
, 0,
721 MEMINIT_HOTPLUG
, altmap
, migratetype
);
723 set_zone_contiguous(zone
);
726 struct auto_movable_stats
{
727 unsigned long kernel_early_pages
;
728 unsigned long movable_pages
;
731 static void auto_movable_stats_account_zone(struct auto_movable_stats
*stats
,
734 if (zone_idx(zone
) == ZONE_MOVABLE
) {
735 stats
->movable_pages
+= zone
->present_pages
;
737 stats
->kernel_early_pages
+= zone
->present_early_pages
;
740 * CMA pages (never on hotplugged memory) behave like
743 stats
->movable_pages
+= zone
->cma_pages
;
744 stats
->kernel_early_pages
-= zone
->cma_pages
;
745 #endif /* CONFIG_CMA */
748 struct auto_movable_group_stats
{
749 unsigned long movable_pages
;
750 unsigned long req_kernel_early_pages
;
753 static int auto_movable_stats_account_group(struct memory_group
*group
,
756 const int ratio
= READ_ONCE(auto_movable_ratio
);
757 struct auto_movable_group_stats
*stats
= arg
;
761 * We don't support modifying the config while the auto-movable online
762 * policy is already enabled. Just avoid the division by zero below.
768 * Calculate how many early kernel pages this group requires to
769 * satisfy the configured zone ratio.
771 pages
= group
->present_movable_pages
* 100 / ratio
;
772 pages
-= group
->present_kernel_pages
;
775 stats
->req_kernel_early_pages
+= pages
;
776 stats
->movable_pages
+= group
->present_movable_pages
;
780 static bool auto_movable_can_online_movable(int nid
, struct memory_group
*group
,
781 unsigned long nr_pages
)
783 unsigned long kernel_early_pages
, movable_pages
;
784 struct auto_movable_group_stats group_stats
= {};
785 struct auto_movable_stats stats
= {};
786 pg_data_t
*pgdat
= NODE_DATA(nid
);
790 /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */
791 if (nid
== NUMA_NO_NODE
) {
792 /* TODO: cache values */
793 for_each_populated_zone(zone
)
794 auto_movable_stats_account_zone(&stats
, zone
);
796 for (i
= 0; i
< MAX_NR_ZONES
; i
++) {
797 zone
= pgdat
->node_zones
+ i
;
798 if (populated_zone(zone
))
799 auto_movable_stats_account_zone(&stats
, zone
);
803 kernel_early_pages
= stats
.kernel_early_pages
;
804 movable_pages
= stats
.movable_pages
;
807 * Kernel memory inside dynamic memory group allows for more MOVABLE
808 * memory within the same group. Remove the effect of all but the
809 * current group from the stats.
811 walk_dynamic_memory_groups(nid
, auto_movable_stats_account_group
,
812 group
, &group_stats
);
813 if (kernel_early_pages
<= group_stats
.req_kernel_early_pages
)
815 kernel_early_pages
-= group_stats
.req_kernel_early_pages
;
816 movable_pages
-= group_stats
.movable_pages
;
818 if (group
&& group
->is_dynamic
)
819 kernel_early_pages
+= group
->present_kernel_pages
;
822 * Test if we could online the given number of pages to ZONE_MOVABLE
823 * and still stay in the configured ratio.
825 movable_pages
+= nr_pages
;
826 return movable_pages
<= (auto_movable_ratio
* kernel_early_pages
) / 100;
830 * Returns a default kernel memory zone for the given pfn range.
831 * If no kernel zone covers this pfn range it will automatically go
832 * to the ZONE_NORMAL.
834 static struct zone
*default_kernel_zone_for_pfn(int nid
, unsigned long start_pfn
,
835 unsigned long nr_pages
)
837 struct pglist_data
*pgdat
= NODE_DATA(nid
);
840 for (zid
= 0; zid
< ZONE_NORMAL
; zid
++) {
841 struct zone
*zone
= &pgdat
->node_zones
[zid
];
843 if (zone_intersects(zone
, start_pfn
, nr_pages
))
847 return &pgdat
->node_zones
[ZONE_NORMAL
];
851 * Determine to which zone to online memory dynamically based on user
852 * configuration and system stats. We care about the following ratio:
856 * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in
857 * one of the kernel zones. CMA pages inside one of the kernel zones really
858 * behaves like ZONE_MOVABLE, so we treat them accordingly.
860 * We don't allow for hotplugged memory in a KERNEL zone to increase the
861 * amount of MOVABLE memory we can have, so we end up with:
863 * MOVABLE : KERNEL_EARLY
865 * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze
866 * boot. We base our calculation on KERNEL_EARLY internally, because:
868 * a) Hotplugged memory in one of the kernel zones can sometimes still get
869 * hotunplugged, especially when hot(un)plugging individual memory blocks.
870 * There is no coordination across memory devices, therefore "automatic"
871 * hotunplugging, as implemented in hypervisors, could result in zone
873 * b) Early/boot memory in one of the kernel zones can usually not get
874 * hotunplugged again (e.g., no firmware interface to unplug, fragmented
875 * with unmovable allocations). While there are corner cases where it might
876 * still work, it is barely relevant in practice.
878 * Exceptions are dynamic memory groups, which allow for more MOVABLE
879 * memory within the same memory group -- because in that case, there is
880 * coordination within the single memory device managed by a single driver.
882 * We rely on "present pages" instead of "managed pages", as the latter is
883 * highly unreliable and dynamic in virtualized environments, and does not
884 * consider boot time allocations. For example, memory ballooning adjusts the
885 * managed pages when inflating/deflating the balloon, and balloon compaction
886 * can even migrate inflated pages between zones.
888 * Using "present pages" is better but some things to keep in mind are:
890 * a) Some memblock allocations, such as for the crashkernel area, are
891 * effectively unused by the kernel, yet they account to "present pages".
892 * Fortunately, these allocations are comparatively small in relevant setups
893 * (e.g., fraction of system memory).
894 * b) Some hotplugged memory blocks in virtualized environments, esecially
895 * hotplugged by virtio-mem, look like they are completely present, however,
896 * only parts of the memory block are actually currently usable.
897 * "present pages" is an upper limit that can get reached at runtime. As
898 * we base our calculations on KERNEL_EARLY, this is not an issue.
900 static struct zone
*auto_movable_zone_for_pfn(int nid
,
901 struct memory_group
*group
,
903 unsigned long nr_pages
)
905 unsigned long online_pages
= 0, max_pages
, end_pfn
;
908 if (!auto_movable_ratio
)
911 if (group
&& !group
->is_dynamic
) {
912 max_pages
= group
->s
.max_pages
;
913 online_pages
= group
->present_movable_pages
;
915 /* If anything is !MOVABLE online the rest !MOVABLE. */
916 if (group
->present_kernel_pages
)
918 } else if (!group
|| group
->d
.unit_pages
== nr_pages
) {
919 max_pages
= nr_pages
;
921 max_pages
= group
->d
.unit_pages
;
923 * Take a look at all online sections in the current unit.
924 * We can safely assume that all pages within a section belong
925 * to the same zone, because dynamic memory groups only deal
926 * with hotplugged memory.
928 pfn
= ALIGN_DOWN(pfn
, group
->d
.unit_pages
);
929 end_pfn
= pfn
+ group
->d
.unit_pages
;
930 for (; pfn
< end_pfn
; pfn
+= PAGES_PER_SECTION
) {
931 page
= pfn_to_online_page(pfn
);
934 /* If anything is !MOVABLE online the rest !MOVABLE. */
935 if (!is_zone_movable_page(page
))
937 online_pages
+= PAGES_PER_SECTION
;
942 * Online MOVABLE if we could *currently* online all remaining parts
943 * MOVABLE. We expect to (add+) online them immediately next, so if
944 * nobody interferes, all will be MOVABLE if possible.
946 nr_pages
= max_pages
- online_pages
;
947 if (!auto_movable_can_online_movable(NUMA_NO_NODE
, group
, nr_pages
))
951 if (auto_movable_numa_aware
&&
952 !auto_movable_can_online_movable(nid
, group
, nr_pages
))
954 #endif /* CONFIG_NUMA */
956 return &NODE_DATA(nid
)->node_zones
[ZONE_MOVABLE
];
958 return default_kernel_zone_for_pfn(nid
, pfn
, nr_pages
);
961 static inline struct zone
*default_zone_for_pfn(int nid
, unsigned long start_pfn
,
962 unsigned long nr_pages
)
964 struct zone
*kernel_zone
= default_kernel_zone_for_pfn(nid
, start_pfn
,
966 struct zone
*movable_zone
= &NODE_DATA(nid
)->node_zones
[ZONE_MOVABLE
];
967 bool in_kernel
= zone_intersects(kernel_zone
, start_pfn
, nr_pages
);
968 bool in_movable
= zone_intersects(movable_zone
, start_pfn
, nr_pages
);
971 * We inherit the existing zone in a simple case where zones do not
972 * overlap in the given range
974 if (in_kernel
^ in_movable
)
975 return (in_kernel
) ? kernel_zone
: movable_zone
;
978 * If the range doesn't belong to any zone or two zones overlap in the
979 * given range then we use movable zone only if movable_node is
980 * enabled because we always online to a kernel zone by default.
982 return movable_node_enabled
? movable_zone
: kernel_zone
;
985 struct zone
*zone_for_pfn_range(int online_type
, int nid
,
986 struct memory_group
*group
, unsigned long start_pfn
,
987 unsigned long nr_pages
)
989 if (online_type
== MMOP_ONLINE_KERNEL
)
990 return default_kernel_zone_for_pfn(nid
, start_pfn
, nr_pages
);
992 if (online_type
== MMOP_ONLINE_MOVABLE
)
993 return &NODE_DATA(nid
)->node_zones
[ZONE_MOVABLE
];
995 if (online_policy
== ONLINE_POLICY_AUTO_MOVABLE
)
996 return auto_movable_zone_for_pfn(nid
, group
, start_pfn
, nr_pages
);
998 return default_zone_for_pfn(nid
, start_pfn
, nr_pages
);
1002 * This function should only be called by memory_block_{online,offline},
1003 * and {online,offline}_pages.
1005 void adjust_present_page_count(struct page
*page
, struct memory_group
*group
,
1008 struct zone
*zone
= page_zone(page
);
1009 const bool movable
= zone_idx(zone
) == ZONE_MOVABLE
;
1012 * We only support onlining/offlining/adding/removing of complete
1013 * memory blocks; therefore, either all is either early or hotplugged.
1015 if (early_section(__pfn_to_section(page_to_pfn(page
))))
1016 zone
->present_early_pages
+= nr_pages
;
1017 zone
->present_pages
+= nr_pages
;
1018 zone
->zone_pgdat
->node_present_pages
+= nr_pages
;
1020 if (group
&& movable
)
1021 group
->present_movable_pages
+= nr_pages
;
1022 else if (group
&& !movable
)
1023 group
->present_kernel_pages
+= nr_pages
;
1026 int mhp_init_memmap_on_memory(unsigned long pfn
, unsigned long nr_pages
,
1029 unsigned long end_pfn
= pfn
+ nr_pages
;
1032 ret
= kasan_add_zero_shadow(__va(PFN_PHYS(pfn
)), PFN_PHYS(nr_pages
));
1036 move_pfn_range_to_zone(zone
, pfn
, nr_pages
, NULL
, MIGRATE_UNMOVABLE
);
1038 for (i
= 0; i
< nr_pages
; i
++)
1039 SetPageVmemmapSelfHosted(pfn_to_page(pfn
+ i
));
1042 * It might be that the vmemmap_pages fully span sections. If that is
1043 * the case, mark those sections online here as otherwise they will be
1046 if (nr_pages
>= PAGES_PER_SECTION
)
1047 online_mem_sections(pfn
, ALIGN_DOWN(end_pfn
, PAGES_PER_SECTION
));
1052 void mhp_deinit_memmap_on_memory(unsigned long pfn
, unsigned long nr_pages
)
1054 unsigned long end_pfn
= pfn
+ nr_pages
;
1057 * It might be that the vmemmap_pages fully span sections. If that is
1058 * the case, mark those sections offline here as otherwise they will be
1061 if (nr_pages
>= PAGES_PER_SECTION
)
1062 offline_mem_sections(pfn
, ALIGN_DOWN(end_pfn
, PAGES_PER_SECTION
));
1065 * The pages associated with this vmemmap have been offlined, so
1066 * we can reset its state here.
1068 remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn
)), pfn
, nr_pages
);
1069 kasan_remove_zero_shadow(__va(PFN_PHYS(pfn
)), PFN_PHYS(nr_pages
));
1072 int __ref
online_pages(unsigned long pfn
, unsigned long nr_pages
,
1073 struct zone
*zone
, struct memory_group
*group
)
1075 unsigned long flags
;
1076 int need_zonelists_rebuild
= 0;
1077 const int nid
= zone_to_nid(zone
);
1079 struct memory_notify arg
;
1082 * {on,off}lining is constrained to full memory sections (or more
1083 * precisely to memory blocks from the user space POV).
1084 * memmap_on_memory is an exception because it reserves initial part
1085 * of the physical memory space for vmemmaps. That space is pageblock
1088 if (WARN_ON_ONCE(!nr_pages
|| !pageblock_aligned(pfn
) ||
1089 !IS_ALIGNED(pfn
+ nr_pages
, PAGES_PER_SECTION
)))
1092 mem_hotplug_begin();
1094 /* associate pfn range with the zone */
1095 move_pfn_range_to_zone(zone
, pfn
, nr_pages
, NULL
, MIGRATE_ISOLATE
);
1097 arg
.start_pfn
= pfn
;
1098 arg
.nr_pages
= nr_pages
;
1099 node_states_check_changes_online(nr_pages
, zone
, &arg
);
1101 ret
= memory_notify(MEM_GOING_ONLINE
, &arg
);
1102 ret
= notifier_to_errno(ret
);
1104 goto failed_addition
;
1107 * Fixup the number of isolated pageblocks before marking the sections
1108 * onlining, such that undo_isolate_page_range() works correctly.
1110 spin_lock_irqsave(&zone
->lock
, flags
);
1111 zone
->nr_isolate_pageblock
+= nr_pages
/ pageblock_nr_pages
;
1112 spin_unlock_irqrestore(&zone
->lock
, flags
);
1115 * If this zone is not populated, then it is not in zonelist.
1116 * This means the page allocator ignores this zone.
1117 * So, zonelist must be updated after online.
1119 if (!populated_zone(zone
)) {
1120 need_zonelists_rebuild
= 1;
1121 setup_zone_pageset(zone
);
1124 online_pages_range(pfn
, nr_pages
);
1125 adjust_present_page_count(pfn_to_page(pfn
), group
, nr_pages
);
1127 node_states_set_node(nid
, &arg
);
1128 if (need_zonelists_rebuild
)
1129 build_all_zonelists(NULL
);
1131 /* Basic onlining is complete, allow allocation of onlined pages. */
1132 undo_isolate_page_range(pfn
, pfn
+ nr_pages
, MIGRATE_MOVABLE
);
1135 * Freshly onlined pages aren't shuffled (e.g., all pages are placed to
1136 * the tail of the freelist when undoing isolation). Shuffle the whole
1137 * zone to make sure the just onlined pages are properly distributed
1138 * across the whole freelist - to create an initial shuffle.
1142 /* reinitialise watermarks and update pcp limits */
1143 init_per_zone_wmark_min();
1148 writeback_set_ratelimit();
1150 memory_notify(MEM_ONLINE
, &arg
);
1155 pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
1156 (unsigned long long) pfn
<< PAGE_SHIFT
,
1157 (((unsigned long long) pfn
+ nr_pages
) << PAGE_SHIFT
) - 1);
1158 memory_notify(MEM_CANCEL_ONLINE
, &arg
);
1159 remove_pfn_range_from_zone(zone
, pfn
, nr_pages
);
1164 static void reset_node_present_pages(pg_data_t
*pgdat
)
1168 for (z
= pgdat
->node_zones
; z
< pgdat
->node_zones
+ MAX_NR_ZONES
; z
++)
1169 z
->present_pages
= 0;
1171 pgdat
->node_present_pages
= 0;
1174 /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
1175 static pg_data_t __ref
*hotadd_init_pgdat(int nid
)
1177 struct pglist_data
*pgdat
;
1180 * NODE_DATA is preallocated (free_area_init) but its internal
1181 * state is not allocated completely. Add missing pieces.
1182 * Completely offline nodes stay around and they just need
1185 pgdat
= NODE_DATA(nid
);
1187 /* init node's zones as empty zones, we don't have any present pages.*/
1188 free_area_init_core_hotplug(pgdat
);
1191 * The node we allocated has no zone fallback lists. For avoiding
1192 * to access not-initialized zonelist, build here.
1194 build_all_zonelists(pgdat
);
1197 * When memory is hot-added, all the memory is in offline state. So
1198 * clear all zones' present_pages because they will be updated in
1199 * online_pages() and offline_pages().
1200 * TODO: should be in free_area_init_core_hotplug?
1202 reset_node_managed_pages(pgdat
);
1203 reset_node_present_pages(pgdat
);
1209 * __try_online_node - online a node if offlined
1211 * @set_node_online: Whether we want to online the node
1212 * called by cpu_up() to online a node without onlined memory.
1215 * 1 -> a new node has been allocated
1216 * 0 -> the node is already online
1217 * -ENOMEM -> the node could not be allocated
1219 static int __try_online_node(int nid
, bool set_node_online
)
1224 if (node_online(nid
))
1227 pgdat
= hotadd_init_pgdat(nid
);
1229 pr_err("Cannot online node %d due to NULL pgdat\n", nid
);
1234 if (set_node_online
) {
1235 node_set_online(nid
);
1236 ret
= register_one_node(nid
);
1244 * Users of this function always want to online/register the node
1246 int try_online_node(int nid
)
1250 mem_hotplug_begin();
1251 ret
= __try_online_node(nid
, true);
1256 static int check_hotplug_memory_range(u64 start
, u64 size
)
1258 /* memory range must be block size aligned */
1259 if (!size
|| !IS_ALIGNED(start
, memory_block_size_bytes()) ||
1260 !IS_ALIGNED(size
, memory_block_size_bytes())) {
1261 pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
1262 memory_block_size_bytes(), start
, size
);
1269 static int online_memory_block(struct memory_block
*mem
, void *arg
)
1271 mem
->online_type
= mhp_default_online_type
;
1272 return device_online(&mem
->dev
);
1275 bool mhp_supports_memmap_on_memory(unsigned long size
)
1277 unsigned long nr_vmemmap_pages
= size
/ PAGE_SIZE
;
1278 unsigned long vmemmap_size
= nr_vmemmap_pages
* sizeof(struct page
);
1279 unsigned long remaining_size
= size
- vmemmap_size
;
1282 * Besides having arch support and the feature enabled at runtime, we
1283 * need a few more assumptions to hold true:
1285 * a) We span a single memory block: memory onlining/offlinin;g happens
1286 * in memory block granularity. We don't want the vmemmap of online
1287 * memory blocks to reside on offline memory blocks. In the future,
1288 * we might want to support variable-sized memory blocks to make the
1289 * feature more versatile.
1291 * b) The vmemmap pages span complete PMDs: We don't want vmemmap code
1292 * to populate memory from the altmap for unrelated parts (i.e.,
1293 * other memory blocks)
1295 * c) The vmemmap pages (and thereby the pages that will be exposed to
1296 * the buddy) have to cover full pageblocks: memory onlining/offlining
1297 * code requires applicable ranges to be page-aligned, for example, to
1298 * set the migratetypes properly.
1300 * TODO: Although we have a check here to make sure that vmemmap pages
1301 * fully populate a PMD, it is not the right place to check for
1302 * this. A much better solution involves improving vmemmap code
1303 * to fallback to base pages when trying to populate vmemmap using
1304 * altmap as an alternative source of memory, and we do not exactly
1305 * populate a single PMD.
1307 return mhp_memmap_on_memory() &&
1308 size
== memory_block_size_bytes() &&
1309 IS_ALIGNED(vmemmap_size
, PMD_SIZE
) &&
1310 IS_ALIGNED(remaining_size
, (pageblock_nr_pages
<< PAGE_SHIFT
));
1314 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
1315 * and online/offline operations (triggered e.g. by sysfs).
1317 * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
1319 int __ref
add_memory_resource(int nid
, struct resource
*res
, mhp_t mhp_flags
)
1321 struct mhp_params params
= { .pgprot
= pgprot_mhp(PAGE_KERNEL
) };
1322 enum memblock_flags memblock_flags
= MEMBLOCK_NONE
;
1323 struct vmem_altmap mhp_altmap
= {};
1324 struct memory_group
*group
= NULL
;
1326 bool new_node
= false;
1330 size
= resource_size(res
);
1332 ret
= check_hotplug_memory_range(start
, size
);
1336 if (mhp_flags
& MHP_NID_IS_MGID
) {
1337 group
= memory_group_find_by_id(nid
);
1343 if (!node_possible(nid
)) {
1344 WARN(1, "node %d was absent from the node_possible_map\n", nid
);
1348 mem_hotplug_begin();
1350 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK
)) {
1351 if (res
->flags
& IORESOURCE_SYSRAM_DRIVER_MANAGED
)
1352 memblock_flags
= MEMBLOCK_DRIVER_MANAGED
;
1353 ret
= memblock_add_node(start
, size
, nid
, memblock_flags
);
1355 goto error_mem_hotplug_end
;
1358 ret
= __try_online_node(nid
, false);
1364 * Self hosted memmap array
1366 if (mhp_flags
& MHP_MEMMAP_ON_MEMORY
) {
1367 if (!mhp_supports_memmap_on_memory(size
)) {
1371 mhp_altmap
.free
= PHYS_PFN(size
);
1372 mhp_altmap
.base_pfn
= PHYS_PFN(start
);
1373 params
.altmap
= &mhp_altmap
;
1376 /* call arch's memory hotadd */
1377 ret
= arch_add_memory(nid
, start
, size
, ¶ms
);
1381 /* create memory block devices after memory was added */
1382 ret
= create_memory_block_devices(start
, size
, mhp_altmap
.alloc
,
1385 arch_remove_memory(start
, size
, NULL
);
1390 /* If sysfs file of new node can't be created, cpu on the node
1391 * can't be hot-added. There is no rollback way now.
1392 * So, check by BUG_ON() to catch it reluctantly..
1393 * We online node here. We can't roll back from here.
1395 node_set_online(nid
);
1396 ret
= __register_one_node(nid
);
1400 register_memory_blocks_under_node(nid
, PFN_DOWN(start
),
1401 PFN_UP(start
+ size
- 1),
1404 /* create new memmap entry */
1405 if (!strcmp(res
->name
, "System RAM"))
1406 firmware_map_add_hotplug(start
, start
+ size
, "System RAM");
1408 /* device_online() will take the lock when calling online_pages() */
1412 * In case we're allowed to merge the resource, flag it and trigger
1413 * merging now that adding succeeded.
1415 if (mhp_flags
& MHP_MERGE_RESOURCE
)
1416 merge_system_ram_resource(res
);
1418 /* online pages if requested */
1419 if (mhp_default_online_type
!= MMOP_OFFLINE
)
1420 walk_memory_blocks(start
, size
, NULL
, online_memory_block
);
1424 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK
))
1425 memblock_remove(start
, size
);
1426 error_mem_hotplug_end
:
1431 /* requires device_hotplug_lock, see add_memory_resource() */
1432 int __ref
__add_memory(int nid
, u64 start
, u64 size
, mhp_t mhp_flags
)
1434 struct resource
*res
;
1437 res
= register_memory_resource(start
, size
, "System RAM");
1439 return PTR_ERR(res
);
1441 ret
= add_memory_resource(nid
, res
, mhp_flags
);
1443 release_memory_resource(res
);
1447 int add_memory(int nid
, u64 start
, u64 size
, mhp_t mhp_flags
)
1451 lock_device_hotplug();
1452 rc
= __add_memory(nid
, start
, size
, mhp_flags
);
1453 unlock_device_hotplug();
1457 EXPORT_SYMBOL_GPL(add_memory
);
1460 * Add special, driver-managed memory to the system as system RAM. Such
1461 * memory is not exposed via the raw firmware-provided memmap as system
1462 * RAM, instead, it is detected and added by a driver - during cold boot,
1463 * after a reboot, and after kexec.
1465 * Reasons why this memory should not be used for the initial memmap of a
1466 * kexec kernel or for placing kexec images:
1467 * - The booting kernel is in charge of determining how this memory will be
1468 * used (e.g., use persistent memory as system RAM)
1469 * - Coordination with a hypervisor is required before this memory
1470 * can be used (e.g., inaccessible parts).
1472 * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided
1473 * memory map") are created. Also, the created memory resource is flagged
1474 * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case
1475 * this memory as well (esp., not place kexec images onto it).
1477 * The resource_name (visible via /proc/iomem) has to have the format
1478 * "System RAM ($DRIVER)".
1480 int add_memory_driver_managed(int nid
, u64 start
, u64 size
,
1481 const char *resource_name
, mhp_t mhp_flags
)
1483 struct resource
*res
;
1486 if (!resource_name
||
1487 strstr(resource_name
, "System RAM (") != resource_name
||
1488 resource_name
[strlen(resource_name
) - 1] != ')')
1491 lock_device_hotplug();
1493 res
= register_memory_resource(start
, size
, resource_name
);
1499 rc
= add_memory_resource(nid
, res
, mhp_flags
);
1501 release_memory_resource(res
);
1504 unlock_device_hotplug();
1507 EXPORT_SYMBOL_GPL(add_memory_driver_managed
);
1510 * Platforms should define arch_get_mappable_range() that provides
1511 * maximum possible addressable physical memory range for which the
1512 * linear mapping could be created. The platform returned address
1513 * range must adhere to these following semantics.
1515 * - range.start <= range.end
1516 * - Range includes both end points [range.start..range.end]
1518 * There is also a fallback definition provided here, allowing the
1519 * entire possible physical address range in case any platform does
1520 * not define arch_get_mappable_range().
1522 struct range __weak
arch_get_mappable_range(void)
1524 struct range mhp_range
= {
1531 struct range
mhp_get_pluggable_range(bool need_mapping
)
1533 const u64 max_phys
= (1ULL << MAX_PHYSMEM_BITS
) - 1;
1534 struct range mhp_range
;
1537 mhp_range
= arch_get_mappable_range();
1538 if (mhp_range
.start
> max_phys
) {
1539 mhp_range
.start
= 0;
1542 mhp_range
.end
= min_t(u64
, mhp_range
.end
, max_phys
);
1544 mhp_range
.start
= 0;
1545 mhp_range
.end
= max_phys
;
1549 EXPORT_SYMBOL_GPL(mhp_get_pluggable_range
);
1551 bool mhp_range_allowed(u64 start
, u64 size
, bool need_mapping
)
1553 struct range mhp_range
= mhp_get_pluggable_range(need_mapping
);
1554 u64 end
= start
+ size
;
1556 if (start
< end
&& start
>= mhp_range
.start
&& (end
- 1) <= mhp_range
.end
)
1559 pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n",
1560 start
, end
, mhp_range
.start
, mhp_range
.end
);
1564 #ifdef CONFIG_MEMORY_HOTREMOVE
1566 * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
1567 * non-lru movable pages and hugepages). Will skip over most unmovable
1568 * pages (esp., pages that can be skipped when offlining), but bail out on
1569 * definitely unmovable pages.
1572 * 0 in case a movable page is found and movable_pfn was updated.
1573 * -ENOENT in case no movable page was found.
1574 * -EBUSY in case a definitely unmovable page was found.
1576 static int scan_movable_pages(unsigned long start
, unsigned long end
,
1577 unsigned long *movable_pfn
)
1581 for (pfn
= start
; pfn
< end
; pfn
++) {
1582 struct page
*page
, *head
;
1585 if (!pfn_valid(pfn
))
1587 page
= pfn_to_page(pfn
);
1590 if (__PageMovable(page
))
1594 * PageOffline() pages that are not marked __PageMovable() and
1595 * have a reference count > 0 (after MEM_GOING_OFFLINE) are
1596 * definitely unmovable. If their reference count would be 0,
1597 * they could at least be skipped when offlining memory.
1599 if (PageOffline(page
) && page_count(page
))
1602 if (!PageHuge(page
))
1604 head
= compound_head(page
);
1606 * This test is racy as we hold no reference or lock. The
1607 * hugetlb page could have been free'ed and head is no longer
1608 * a hugetlb page before the following check. In such unlikely
1609 * cases false positives and negatives are possible. Calling
1610 * code must deal with these scenarios.
1612 if (HPageMigratable(head
))
1614 skip
= compound_nr(head
) - (page
- head
);
1624 do_migrate_range(unsigned long start_pfn
, unsigned long end_pfn
)
1627 struct page
*page
, *head
;
1630 static DEFINE_RATELIMIT_STATE(migrate_rs
, DEFAULT_RATELIMIT_INTERVAL
,
1631 DEFAULT_RATELIMIT_BURST
);
1633 for (pfn
= start_pfn
; pfn
< end_pfn
; pfn
++) {
1634 struct folio
*folio
;
1636 if (!pfn_valid(pfn
))
1638 page
= pfn_to_page(pfn
);
1639 folio
= page_folio(page
);
1640 head
= &folio
->page
;
1642 if (PageHuge(page
)) {
1643 pfn
= page_to_pfn(head
) + compound_nr(head
) - 1;
1644 isolate_hugetlb(head
, &source
);
1646 } else if (PageTransHuge(page
))
1647 pfn
= page_to_pfn(head
) + thp_nr_pages(page
) - 1;
1650 * HWPoison pages have elevated reference counts so the migration would
1651 * fail on them. It also doesn't make any sense to migrate them in the
1652 * first place. Still try to unmap such a page in case it is still mapped
1653 * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
1654 * the unmap as the catch all safety net).
1656 if (PageHWPoison(page
)) {
1657 if (WARN_ON(folio_test_lru(folio
)))
1658 folio_isolate_lru(folio
);
1659 if (folio_mapped(folio
))
1660 try_to_unmap(folio
, TTU_IGNORE_MLOCK
);
1664 if (!get_page_unless_zero(page
))
1667 * We can skip free pages. And we can deal with pages on
1668 * LRU and non-lru movable pages.
1671 ret
= isolate_lru_page(page
);
1673 ret
= isolate_movable_page(page
, ISOLATE_UNEVICTABLE
);
1674 if (!ret
) { /* Success */
1675 list_add_tail(&page
->lru
, &source
);
1676 if (!__PageMovable(page
))
1677 inc_node_page_state(page
, NR_ISOLATED_ANON
+
1678 page_is_file_lru(page
));
1681 if (__ratelimit(&migrate_rs
)) {
1682 pr_warn("failed to isolate pfn %lx\n", pfn
);
1683 dump_page(page
, "isolation failed");
1688 if (!list_empty(&source
)) {
1689 nodemask_t nmask
= node_states
[N_MEMORY
];
1690 struct migration_target_control mtc
= {
1692 .gfp_mask
= GFP_USER
| __GFP_MOVABLE
| __GFP_RETRY_MAYFAIL
,
1696 * We have checked that migration range is on a single zone so
1697 * we can use the nid of the first page to all the others.
1699 mtc
.nid
= page_to_nid(list_first_entry(&source
, struct page
, lru
));
1702 * try to allocate from a different node but reuse this node
1703 * if there are no other online nodes to be used (e.g. we are
1704 * offlining a part of the only existing node)
1706 node_clear(mtc
.nid
, nmask
);
1707 if (nodes_empty(nmask
))
1708 node_set(mtc
.nid
, nmask
);
1709 ret
= migrate_pages(&source
, alloc_migration_target
, NULL
,
1710 (unsigned long)&mtc
, MIGRATE_SYNC
, MR_MEMORY_HOTPLUG
, NULL
);
1712 list_for_each_entry(page
, &source
, lru
) {
1713 if (__ratelimit(&migrate_rs
)) {
1714 pr_warn("migrating pfn %lx failed ret:%d\n",
1715 page_to_pfn(page
), ret
);
1716 dump_page(page
, "migration failure");
1719 putback_movable_pages(&source
);
1726 static int __init
cmdline_parse_movable_node(char *p
)
1728 movable_node_enabled
= true;
1731 early_param("movable_node", cmdline_parse_movable_node
);
1733 /* check which state of node_states will be changed when offline memory */
1734 static void node_states_check_changes_offline(unsigned long nr_pages
,
1735 struct zone
*zone
, struct memory_notify
*arg
)
1737 struct pglist_data
*pgdat
= zone
->zone_pgdat
;
1738 unsigned long present_pages
= 0;
1741 arg
->status_change_nid
= NUMA_NO_NODE
;
1742 arg
->status_change_nid_normal
= NUMA_NO_NODE
;
1745 * Check whether node_states[N_NORMAL_MEMORY] will be changed.
1746 * If the memory to be offline is within the range
1747 * [0..ZONE_NORMAL], and it is the last present memory there,
1748 * the zones in that range will become empty after the offlining,
1749 * thus we can determine that we need to clear the node from
1750 * node_states[N_NORMAL_MEMORY].
1752 for (zt
= 0; zt
<= ZONE_NORMAL
; zt
++)
1753 present_pages
+= pgdat
->node_zones
[zt
].present_pages
;
1754 if (zone_idx(zone
) <= ZONE_NORMAL
&& nr_pages
>= present_pages
)
1755 arg
->status_change_nid_normal
= zone_to_nid(zone
);
1758 * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
1759 * does not apply as we don't support 32bit.
1760 * Here we count the possible pages from ZONE_MOVABLE.
1761 * If after having accounted all the pages, we see that the nr_pages
1762 * to be offlined is over or equal to the accounted pages,
1763 * we know that the node will become empty, and so, we can clear
1764 * it for N_MEMORY as well.
1766 present_pages
+= pgdat
->node_zones
[ZONE_MOVABLE
].present_pages
;
1768 if (nr_pages
>= present_pages
)
1769 arg
->status_change_nid
= zone_to_nid(zone
);
1772 static void node_states_clear_node(int node
, struct memory_notify
*arg
)
1774 if (arg
->status_change_nid_normal
>= 0)
1775 node_clear_state(node
, N_NORMAL_MEMORY
);
1777 if (arg
->status_change_nid
>= 0)
1778 node_clear_state(node
, N_MEMORY
);
1781 static int count_system_ram_pages_cb(unsigned long start_pfn
,
1782 unsigned long nr_pages
, void *data
)
1784 unsigned long *nr_system_ram_pages
= data
;
1786 *nr_system_ram_pages
+= nr_pages
;
1790 int __ref
offline_pages(unsigned long start_pfn
, unsigned long nr_pages
,
1791 struct zone
*zone
, struct memory_group
*group
)
1793 const unsigned long end_pfn
= start_pfn
+ nr_pages
;
1794 unsigned long pfn
, system_ram_pages
= 0;
1795 const int node
= zone_to_nid(zone
);
1796 unsigned long flags
;
1797 struct memory_notify arg
;
1802 * {on,off}lining is constrained to full memory sections (or more
1803 * precisely to memory blocks from the user space POV).
1804 * memmap_on_memory is an exception because it reserves initial part
1805 * of the physical memory space for vmemmaps. That space is pageblock
1808 if (WARN_ON_ONCE(!nr_pages
|| !pageblock_aligned(start_pfn
) ||
1809 !IS_ALIGNED(start_pfn
+ nr_pages
, PAGES_PER_SECTION
)))
1812 mem_hotplug_begin();
1815 * Don't allow to offline memory blocks that contain holes.
1816 * Consequently, memory blocks with holes can never get onlined
1817 * via the hotplug path - online_pages() - as hotplugged memory has
1818 * no holes. This way, we e.g., don't have to worry about marking
1819 * memory holes PG_reserved, don't need pfn_valid() checks, and can
1820 * avoid using walk_system_ram_range() later.
1822 walk_system_ram_range(start_pfn
, nr_pages
, &system_ram_pages
,
1823 count_system_ram_pages_cb
);
1824 if (system_ram_pages
!= nr_pages
) {
1826 reason
= "memory holes";
1827 goto failed_removal
;
1831 * We only support offlining of memory blocks managed by a single zone,
1832 * checked by calling code. This is just a sanity check that we might
1833 * want to remove in the future.
1835 if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn
)) != zone
||
1836 page_zone(pfn_to_page(end_pfn
- 1)) != zone
)) {
1838 reason
= "multizone range";
1839 goto failed_removal
;
1843 * Disable pcplists so that page isolation cannot race with freeing
1844 * in a way that pages from isolated pageblock are left on pcplists.
1846 zone_pcp_disable(zone
);
1847 lru_cache_disable();
1849 /* set above range as isolated */
1850 ret
= start_isolate_page_range(start_pfn
, end_pfn
,
1852 MEMORY_OFFLINE
| REPORT_FAILURE
,
1853 GFP_USER
| __GFP_MOVABLE
| __GFP_RETRY_MAYFAIL
);
1855 reason
= "failure to isolate range";
1856 goto failed_removal_pcplists_disabled
;
1859 arg
.start_pfn
= start_pfn
;
1860 arg
.nr_pages
= nr_pages
;
1861 node_states_check_changes_offline(nr_pages
, zone
, &arg
);
1863 ret
= memory_notify(MEM_GOING_OFFLINE
, &arg
);
1864 ret
= notifier_to_errno(ret
);
1866 reason
= "notifier failure";
1867 goto failed_removal_isolated
;
1873 if (signal_pending(current
)) {
1875 reason
= "signal backoff";
1876 goto failed_removal_isolated
;
1881 ret
= scan_movable_pages(pfn
, end_pfn
, &pfn
);
1884 * TODO: fatal migration failures should bail
1887 do_migrate_range(pfn
, end_pfn
);
1891 if (ret
!= -ENOENT
) {
1892 reason
= "unmovable page";
1893 goto failed_removal_isolated
;
1897 * Dissolve free hugepages in the memory block before doing
1898 * offlining actually in order to make hugetlbfs's object
1899 * counting consistent.
1901 ret
= dissolve_free_huge_pages(start_pfn
, end_pfn
);
1903 reason
= "failure to dissolve huge pages";
1904 goto failed_removal_isolated
;
1907 ret
= test_pages_isolated(start_pfn
, end_pfn
, MEMORY_OFFLINE
);
1911 /* Mark all sections offline and remove free pages from the buddy. */
1912 __offline_isolated_pages(start_pfn
, end_pfn
);
1913 pr_debug("Offlined Pages %ld\n", nr_pages
);
1916 * The memory sections are marked offline, and the pageblock flags
1917 * effectively stale; nobody should be touching them. Fixup the number
1918 * of isolated pageblocks, memory onlining will properly revert this.
1920 spin_lock_irqsave(&zone
->lock
, flags
);
1921 zone
->nr_isolate_pageblock
-= nr_pages
/ pageblock_nr_pages
;
1922 spin_unlock_irqrestore(&zone
->lock
, flags
);
1925 zone_pcp_enable(zone
);
1927 /* removal success */
1928 adjust_managed_page_count(pfn_to_page(start_pfn
), -nr_pages
);
1929 adjust_present_page_count(pfn_to_page(start_pfn
), group
, -nr_pages
);
1931 /* reinitialise watermarks and update pcp limits */
1932 init_per_zone_wmark_min();
1934 if (!populated_zone(zone
)) {
1935 zone_pcp_reset(zone
);
1936 build_all_zonelists(NULL
);
1939 node_states_clear_node(node
, &arg
);
1940 if (arg
.status_change_nid
>= 0) {
1941 kcompactd_stop(node
);
1945 writeback_set_ratelimit();
1947 memory_notify(MEM_OFFLINE
, &arg
);
1948 remove_pfn_range_from_zone(zone
, start_pfn
, nr_pages
);
1952 failed_removal_isolated
:
1953 /* pushback to free area */
1954 undo_isolate_page_range(start_pfn
, end_pfn
, MIGRATE_MOVABLE
);
1955 memory_notify(MEM_CANCEL_OFFLINE
, &arg
);
1956 failed_removal_pcplists_disabled
:
1958 zone_pcp_enable(zone
);
1960 pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
1961 (unsigned long long) start_pfn
<< PAGE_SHIFT
,
1962 ((unsigned long long) end_pfn
<< PAGE_SHIFT
) - 1,
1968 static int check_memblock_offlined_cb(struct memory_block
*mem
, void *arg
)
1973 if (unlikely(mem
->state
!= MEM_OFFLINE
)) {
1974 phys_addr_t beginpa
, endpa
;
1976 beginpa
= PFN_PHYS(section_nr_to_pfn(mem
->start_section_nr
));
1977 endpa
= beginpa
+ memory_block_size_bytes() - 1;
1978 pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
1986 static int get_nr_vmemmap_pages_cb(struct memory_block
*mem
, void *arg
)
1989 * If not set, continue with the next block.
1991 return mem
->nr_vmemmap_pages
;
1994 static int check_cpu_on_node(int nid
)
1998 for_each_present_cpu(cpu
) {
1999 if (cpu_to_node(cpu
) == nid
)
2001 * the cpu on this node isn't removed, and we can't
2002 * offline this node.
2010 static int check_no_memblock_for_node_cb(struct memory_block
*mem
, void *arg
)
2012 int nid
= *(int *)arg
;
2015 * If a memory block belongs to multiple nodes, the stored nid is not
2016 * reliable. However, such blocks are always online (e.g., cannot get
2017 * offlined) and, therefore, are still spanned by the node.
2019 return mem
->nid
== nid
? -EEXIST
: 0;
2026 * Offline a node if all memory sections and cpus of the node are removed.
2028 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2029 * and online/offline operations before this call.
2031 void try_offline_node(int nid
)
2036 * If the node still spans pages (especially ZONE_DEVICE), don't
2037 * offline it. A node spans memory after move_pfn_range_to_zone(),
2038 * e.g., after the memory block was onlined.
2040 if (node_spanned_pages(nid
))
2044 * Especially offline memory blocks might not be spanned by the
2045 * node. They will get spanned by the node once they get onlined.
2046 * However, they link to the node in sysfs and can get onlined later.
2048 rc
= for_each_memory_block(&nid
, check_no_memblock_for_node_cb
);
2052 if (check_cpu_on_node(nid
))
2056 * all memory/cpu of this node are removed, we can offline this
2059 node_set_offline(nid
);
2060 unregister_one_node(nid
);
2062 EXPORT_SYMBOL(try_offline_node
);
2064 static int __ref
try_remove_memory(u64 start
, u64 size
)
2066 struct vmem_altmap mhp_altmap
= {};
2067 struct vmem_altmap
*altmap
= NULL
;
2068 unsigned long nr_vmemmap_pages
;
2069 int rc
= 0, nid
= NUMA_NO_NODE
;
2071 BUG_ON(check_hotplug_memory_range(start
, size
));
2074 * All memory blocks must be offlined before removing memory. Check
2075 * whether all memory blocks in question are offline and return error
2076 * if this is not the case.
2078 * While at it, determine the nid. Note that if we'd have mixed nodes,
2079 * we'd only try to offline the last determined one -- which is good
2080 * enough for the cases we care about.
2082 rc
= walk_memory_blocks(start
, size
, &nid
, check_memblock_offlined_cb
);
2087 * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in
2088 * the same granularity it was added - a single memory block.
2090 if (mhp_memmap_on_memory()) {
2091 nr_vmemmap_pages
= walk_memory_blocks(start
, size
, NULL
,
2092 get_nr_vmemmap_pages_cb
);
2093 if (nr_vmemmap_pages
) {
2094 if (size
!= memory_block_size_bytes()) {
2095 pr_warn("Refuse to remove %#llx - %#llx,"
2096 "wrong granularity\n",
2097 start
, start
+ size
);
2102 * Let remove_pmd_table->free_hugepage_table do the
2103 * right thing if we used vmem_altmap when hot-adding
2106 mhp_altmap
.alloc
= nr_vmemmap_pages
;
2107 altmap
= &mhp_altmap
;
2111 /* remove memmap entry */
2112 firmware_map_remove(start
, start
+ size
, "System RAM");
2115 * Memory block device removal under the device_hotplug_lock is
2116 * a barrier against racing online attempts.
2118 remove_memory_block_devices(start
, size
);
2120 mem_hotplug_begin();
2122 arch_remove_memory(start
, size
, altmap
);
2124 if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK
)) {
2125 memblock_phys_free(start
, size
);
2126 memblock_remove(start
, size
);
2129 release_mem_region_adjustable(start
, size
);
2131 if (nid
!= NUMA_NO_NODE
)
2132 try_offline_node(nid
);
2139 * __remove_memory - Remove memory if every memory block is offline
2140 * @start: physical address of the region to remove
2141 * @size: size of the region to remove
2143 * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
2144 * and online/offline operations before this call, as required by
2145 * try_offline_node().
2147 void __remove_memory(u64 start
, u64 size
)
2151 * trigger BUG() if some memory is not offlined prior to calling this
2154 if (try_remove_memory(start
, size
))
2159 * Remove memory if every memory block is offline, otherwise return -EBUSY is
2160 * some memory is not offline
2162 int remove_memory(u64 start
, u64 size
)
2166 lock_device_hotplug();
2167 rc
= try_remove_memory(start
, size
);
2168 unlock_device_hotplug();
2172 EXPORT_SYMBOL_GPL(remove_memory
);
2174 static int try_offline_memory_block(struct memory_block
*mem
, void *arg
)
2176 uint8_t online_type
= MMOP_ONLINE_KERNEL
;
2177 uint8_t **online_types
= arg
;
2182 * Sense the online_type via the zone of the memory block. Offlining
2183 * with multiple zones within one memory block will be rejected
2184 * by offlining code ... so we don't care about that.
2186 page
= pfn_to_online_page(section_nr_to_pfn(mem
->start_section_nr
));
2187 if (page
&& zone_idx(page_zone(page
)) == ZONE_MOVABLE
)
2188 online_type
= MMOP_ONLINE_MOVABLE
;
2190 rc
= device_offline(&mem
->dev
);
2192 * Default is MMOP_OFFLINE - change it only if offlining succeeded,
2193 * so try_reonline_memory_block() can do the right thing.
2196 **online_types
= online_type
;
2199 /* Ignore if already offline. */
2200 return rc
< 0 ? rc
: 0;
2203 static int try_reonline_memory_block(struct memory_block
*mem
, void *arg
)
2205 uint8_t **online_types
= arg
;
2208 if (**online_types
!= MMOP_OFFLINE
) {
2209 mem
->online_type
= **online_types
;
2210 rc
= device_online(&mem
->dev
);
2212 pr_warn("%s: Failed to re-online memory: %d",
2216 /* Continue processing all remaining memory blocks. */
2222 * Try to offline and remove memory. Might take a long time to finish in case
2223 * memory is still in use. Primarily useful for memory devices that logically
2224 * unplugged all memory (so it's no longer in use) and want to offline + remove
2227 int offline_and_remove_memory(u64 start
, u64 size
)
2229 const unsigned long mb_count
= size
/ memory_block_size_bytes();
2230 uint8_t *online_types
, *tmp
;
2233 if (!IS_ALIGNED(start
, memory_block_size_bytes()) ||
2234 !IS_ALIGNED(size
, memory_block_size_bytes()) || !size
)
2238 * We'll remember the old online type of each memory block, so we can
2239 * try to revert whatever we did when offlining one memory block fails
2240 * after offlining some others succeeded.
2242 online_types
= kmalloc_array(mb_count
, sizeof(*online_types
),
2247 * Initialize all states to MMOP_OFFLINE, so when we abort processing in
2248 * try_offline_memory_block(), we'll skip all unprocessed blocks in
2249 * try_reonline_memory_block().
2251 memset(online_types
, MMOP_OFFLINE
, mb_count
);
2253 lock_device_hotplug();
2256 rc
= walk_memory_blocks(start
, size
, &tmp
, try_offline_memory_block
);
2259 * In case we succeeded to offline all memory, remove it.
2260 * This cannot fail as it cannot get onlined in the meantime.
2263 rc
= try_remove_memory(start
, size
);
2265 pr_err("%s: Failed to remove memory: %d", __func__
, rc
);
2269 * Rollback what we did. While memory onlining might theoretically fail
2270 * (nacked by a notifier), it barely ever happens.
2274 walk_memory_blocks(start
, size
, &tmp
,
2275 try_reonline_memory_block
);
2277 unlock_device_hotplug();
2279 kfree(online_types
);
2282 EXPORT_SYMBOL_GPL(offline_and_remove_memory
);
2283 #endif /* CONFIG_MEMORY_HOTREMOVE */