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Diffstat (limited to 'mm/memory_hotplug.c')
| -rw-r--r-- | mm/memory_hotplug.c | 2282 |
1 files changed, 2282 insertions, 0 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c new file mode 100644 index 000000000..3b9d3a4b4 --- /dev/null +++ b/mm/memory_hotplug.c @@ -0,0 +1,2282 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/mm/memory_hotplug.c + * + * Copyright (C) + */ + +#include <linux/stddef.h> +#include <linux/mm.h> +#include <linux/sched/signal.h> +#include <linux/swap.h> +#include <linux/interrupt.h> +#include <linux/pagemap.h> +#include <linux/compiler.h> +#include <linux/export.h> +#include <linux/pagevec.h> +#include <linux/writeback.h> +#include <linux/slab.h> +#include <linux/sysctl.h> +#include <linux/cpu.h> +#include <linux/memory.h> +#include <linux/memremap.h> +#include <linux/memory_hotplug.h> +#include <linux/vmalloc.h> +#include <linux/ioport.h> +#include <linux/delay.h> +#include <linux/migrate.h> +#include <linux/page-isolation.h> +#include <linux/pfn.h> +#include <linux/suspend.h> +#include <linux/mm_inline.h> +#include <linux/firmware-map.h> +#include <linux/stop_machine.h> +#include <linux/hugetlb.h> +#include <linux/memblock.h> +#include <linux/compaction.h> +#include <linux/rmap.h> +#include <linux/module.h> + +#include <asm/tlbflush.h> + +#include "internal.h" +#include "shuffle.h" + +#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY +/* + * memory_hotplug.memmap_on_memory parameter + */ +static bool memmap_on_memory __ro_after_init; +module_param(memmap_on_memory, bool, 0444); +MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug"); + +static inline bool mhp_memmap_on_memory(void) +{ + return memmap_on_memory; +} +#else +static inline bool mhp_memmap_on_memory(void) +{ + return false; +} +#endif + +enum { + ONLINE_POLICY_CONTIG_ZONES = 0, + ONLINE_POLICY_AUTO_MOVABLE, +}; + +static const char * const online_policy_to_str[] = { + [ONLINE_POLICY_CONTIG_ZONES] = "contig-zones", + [ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable", +}; + +static int set_online_policy(const char *val, const struct kernel_param *kp) +{ + int ret = sysfs_match_string(online_policy_to_str, val); + + if (ret < 0) + return ret; + *((int *)kp->arg) = ret; + return 0; +} + +static int get_online_policy(char *buffer, const struct kernel_param *kp) +{ + return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]); +} + +/* + * memory_hotplug.online_policy: configure online behavior when onlining without + * specifying a zone (MMOP_ONLINE) + * + * "contig-zones": keep zone contiguous + * "auto-movable": online memory to ZONE_MOVABLE if the configuration + * (auto_movable_ratio, auto_movable_numa_aware) allows for it + */ +static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES; +static const struct kernel_param_ops online_policy_ops = { + .set = set_online_policy, + .get = get_online_policy, +}; +module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644); +MODULE_PARM_DESC(online_policy, + "Set the online policy (\"contig-zones\", \"auto-movable\") " + "Default: \"contig-zones\""); + +/* + * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio + * + * The ratio represent an upper limit and the kernel might decide to not + * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory + * doesn't allow for more MOVABLE memory. + */ +static unsigned int auto_movable_ratio __read_mostly = 301; +module_param(auto_movable_ratio, uint, 0644); +MODULE_PARM_DESC(auto_movable_ratio, + "Set the maximum ratio of MOVABLE:KERNEL memory in the system " + "in percent for \"auto-movable\" online policy. Default: 301"); + +/* + * memory_hotplug.auto_movable_numa_aware: consider numa node stats + */ +#ifdef CONFIG_NUMA +static bool auto_movable_numa_aware __read_mostly = true; +module_param(auto_movable_numa_aware, bool, 0644); +MODULE_PARM_DESC(auto_movable_numa_aware, + "Consider numa node stats in addition to global stats in " + "\"auto-movable\" online policy. Default: true"); +#endif /* CONFIG_NUMA */ + +/* + * online_page_callback contains pointer to current page onlining function. + * Initially it is generic_online_page(). If it is required it could be + * changed by calling set_online_page_callback() for callback registration + * and restore_online_page_callback() for generic callback restore. + */ + +static online_page_callback_t online_page_callback = generic_online_page; +static DEFINE_MUTEX(online_page_callback_lock); + +DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock); + +void get_online_mems(void) +{ + percpu_down_read(&mem_hotplug_lock); +} + +void put_online_mems(void) +{ + percpu_up_read(&mem_hotplug_lock); +} + +bool movable_node_enabled = false; + +#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE +int mhp_default_online_type = MMOP_OFFLINE; +#else +int mhp_default_online_type = MMOP_ONLINE; +#endif + +static int __init setup_memhp_default_state(char *str) +{ + const int online_type = mhp_online_type_from_str(str); + + if (online_type >= 0) + mhp_default_online_type = online_type; + + return 1; +} +__setup("memhp_default_state=", setup_memhp_default_state); + +void mem_hotplug_begin(void) +{ + cpus_read_lock(); + percpu_down_write(&mem_hotplug_lock); +} + +void mem_hotplug_done(void) +{ + percpu_up_write(&mem_hotplug_lock); + cpus_read_unlock(); +} + +u64 max_mem_size = U64_MAX; + +/* add this memory to iomem resource */ +static struct resource *register_memory_resource(u64 start, u64 size, + const char *resource_name) +{ + struct resource *res; + unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + + if (strcmp(resource_name, "System RAM")) + flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED; + + if (!mhp_range_allowed(start, size, true)) + return ERR_PTR(-E2BIG); + + /* + * Make sure value parsed from 'mem=' only restricts memory adding + * while booting, so that memory hotplug won't be impacted. Please + * refer to document of 'mem=' in kernel-parameters.txt for more + * details. + */ + if (start + size > max_mem_size && system_state < SYSTEM_RUNNING) + return ERR_PTR(-E2BIG); + + /* + * Request ownership of the new memory range. This might be + * a child of an existing resource that was present but + * not marked as busy. + */ + res = __request_region(&iomem_resource, start, size, + resource_name, flags); + + if (!res) { + pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n", + start, start + size); + return ERR_PTR(-EEXIST); + } + return res; +} + +static void release_memory_resource(struct resource *res) +{ + if (!res) + return; + release_resource(res); + kfree(res); +} + +static int check_pfn_span(unsigned long pfn, unsigned long nr_pages) +{ + /* + * Disallow all operations smaller than a sub-section and only + * allow operations smaller than a section for + * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range() + * enforces a larger memory_block_size_bytes() granularity for + * memory that will be marked online, so this check should only + * fire for direct arch_{add,remove}_memory() users outside of + * add_memory_resource(). + */ + unsigned long min_align; + + if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) + min_align = PAGES_PER_SUBSECTION; + else + min_align = PAGES_PER_SECTION; + if (!IS_ALIGNED(pfn | nr_pages, min_align)) + return -EINVAL; + return 0; +} + +/* + * Return page for the valid pfn only if the page is online. All pfn + * walkers which rely on the fully initialized page->flags and others + * should use this rather than pfn_valid && pfn_to_page + */ +struct page *pfn_to_online_page(unsigned long pfn) +{ + unsigned long nr = pfn_to_section_nr(pfn); + struct dev_pagemap *pgmap; + struct mem_section *ms; + + if (nr >= NR_MEM_SECTIONS) + return NULL; + + ms = __nr_to_section(nr); + if (!online_section(ms)) + return NULL; + + /* + * Save some code text when online_section() + + * pfn_section_valid() are sufficient. + */ + if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn)) + return NULL; + + if (!pfn_section_valid(ms, pfn)) + return NULL; + + if (!online_device_section(ms)) + return pfn_to_page(pfn); + + /* + * Slowpath: when ZONE_DEVICE collides with + * ZONE_{NORMAL,MOVABLE} within the same section some pfns in + * the section may be 'offline' but 'valid'. Only + * get_dev_pagemap() can determine sub-section online status. + */ + pgmap = get_dev_pagemap(pfn, NULL); + put_dev_pagemap(pgmap); + + /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */ + if (pgmap) + return NULL; + + return pfn_to_page(pfn); +} +EXPORT_SYMBOL_GPL(pfn_to_online_page); + +int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages, + struct mhp_params *params) +{ + const unsigned long end_pfn = pfn + nr_pages; + unsigned long cur_nr_pages; + int err; + struct vmem_altmap *altmap = params->altmap; + + if (WARN_ON_ONCE(!pgprot_val(params->pgprot))) + return -EINVAL; + + VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false)); + + if (altmap) { + /* + * Validate altmap is within bounds of the total request + */ + if (altmap->base_pfn != pfn + || vmem_altmap_offset(altmap) > nr_pages) { + pr_warn_once("memory add fail, invalid altmap\n"); + return -EINVAL; + } + altmap->alloc = 0; + } + + if (check_pfn_span(pfn, nr_pages)) { + WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1); + return -EINVAL; + } + + for (; pfn < end_pfn; pfn += cur_nr_pages) { + /* Select all remaining pages up to the next section boundary */ + cur_nr_pages = min(end_pfn - pfn, + SECTION_ALIGN_UP(pfn + 1) - pfn); + err = sparse_add_section(nid, pfn, cur_nr_pages, altmap, + params->pgmap); + if (err) + break; + cond_resched(); + } + vmemmap_populate_print_last(); + return err; +} + +/* find the smallest valid pfn in the range [start_pfn, end_pfn) */ +static unsigned long find_smallest_section_pfn(int nid, struct zone *zone, + unsigned long start_pfn, + unsigned long end_pfn) +{ + for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) { + if (unlikely(!pfn_to_online_page(start_pfn))) + continue; + + if (unlikely(pfn_to_nid(start_pfn) != nid)) + continue; + + if (zone != page_zone(pfn_to_page(start_pfn))) + continue; + + return start_pfn; + } + + return 0; +} + +/* find the biggest valid pfn in the range [start_pfn, end_pfn). */ +static unsigned long find_biggest_section_pfn(int nid, struct zone *zone, + unsigned long start_pfn, + unsigned long end_pfn) +{ + unsigned long pfn; + + /* pfn is the end pfn of a memory section. */ + pfn = end_pfn - 1; + for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) { + if (unlikely(!pfn_to_online_page(pfn))) + continue; + + if (unlikely(pfn_to_nid(pfn) != nid)) + continue; + + if (zone != page_zone(pfn_to_page(pfn))) + continue; + + return pfn; + } + + return 0; +} + +static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, + unsigned long end_pfn) +{ + unsigned long pfn; + int nid = zone_to_nid(zone); + + if (zone->zone_start_pfn == start_pfn) { + /* + * If the section is smallest section in the zone, it need + * shrink zone->zone_start_pfn and zone->zone_spanned_pages. + * In this case, we find second smallest valid mem_section + * for shrinking zone. + */ + pfn = find_smallest_section_pfn(nid, zone, end_pfn, + zone_end_pfn(zone)); + if (pfn) { + zone->spanned_pages = zone_end_pfn(zone) - pfn; + zone->zone_start_pfn = pfn; + } else { + zone->zone_start_pfn = 0; + zone->spanned_pages = 0; + } + } else if (zone_end_pfn(zone) == end_pfn) { + /* + * If the section is biggest section in the zone, it need + * shrink zone->spanned_pages. + * In this case, we find second biggest valid mem_section for + * shrinking zone. + */ + pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn, + start_pfn); + if (pfn) + zone->spanned_pages = pfn - zone->zone_start_pfn + 1; + else { + zone->zone_start_pfn = 0; + zone->spanned_pages = 0; + } + } +} + +static void update_pgdat_span(struct pglist_data *pgdat) +{ + unsigned long node_start_pfn = 0, node_end_pfn = 0; + struct zone *zone; + + for (zone = pgdat->node_zones; + zone < pgdat->node_zones + MAX_NR_ZONES; zone++) { + unsigned long end_pfn = zone_end_pfn(zone); + + /* No need to lock the zones, they can't change. */ + if (!zone->spanned_pages) + continue; + if (!node_end_pfn) { + node_start_pfn = zone->zone_start_pfn; + node_end_pfn = end_pfn; + continue; + } + + if (end_pfn > node_end_pfn) + node_end_pfn = end_pfn; + if (zone->zone_start_pfn < node_start_pfn) + node_start_pfn = zone->zone_start_pfn; + } + + pgdat->node_start_pfn = node_start_pfn; + pgdat->node_spanned_pages = node_end_pfn - node_start_pfn; +} + +void __ref remove_pfn_range_from_zone(struct zone *zone, + unsigned long start_pfn, + unsigned long nr_pages) +{ + const unsigned long end_pfn = start_pfn + nr_pages; + struct pglist_data *pgdat = zone->zone_pgdat; + unsigned long pfn, cur_nr_pages; + + /* Poison struct pages because they are now uninitialized again. */ + for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) { + cond_resched(); + + /* Select all remaining pages up to the next section boundary */ + cur_nr_pages = + min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn); + page_init_poison(pfn_to_page(pfn), + sizeof(struct page) * cur_nr_pages); + } + + /* + * Zone shrinking code cannot properly deal with ZONE_DEVICE. So + * we will not try to shrink the zones - which is okay as + * set_zone_contiguous() cannot deal with ZONE_DEVICE either way. + */ + if (zone_is_zone_device(zone)) + return; + + clear_zone_contiguous(zone); + + shrink_zone_span(zone, start_pfn, start_pfn + nr_pages); + update_pgdat_span(pgdat); + + set_zone_contiguous(zone); +} + +static void __remove_section(unsigned long pfn, unsigned long nr_pages, + unsigned long map_offset, + struct vmem_altmap *altmap) +{ + struct mem_section *ms = __pfn_to_section(pfn); + + if (WARN_ON_ONCE(!valid_section(ms))) + return; + + sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap); +} + +/** + * __remove_pages() - remove sections of pages + * @pfn: starting pageframe (must be aligned to start of a section) + * @nr_pages: number of pages to remove (must be multiple of section size) + * @altmap: alternative device page map or %NULL if default memmap is used + * + * Generic helper function to remove section mappings and sysfs entries + * for the section of the memory we are removing. Caller needs to make + * sure that pages are marked reserved and zones are adjust properly by + * calling offline_pages(). + */ +void __remove_pages(unsigned long pfn, unsigned long nr_pages, + struct vmem_altmap *altmap) +{ + const unsigned long end_pfn = pfn + nr_pages; + unsigned long cur_nr_pages; + unsigned long map_offset = 0; + + map_offset = vmem_altmap_offset(altmap); + + if (check_pfn_span(pfn, nr_pages)) { + WARN(1, "Misaligned %s start: %#lx end: #%lx\n", __func__, pfn, pfn + nr_pages - 1); + return; + } + + for (; pfn < end_pfn; pfn += cur_nr_pages) { + cond_resched(); + /* Select all remaining pages up to the next section boundary */ + cur_nr_pages = min(end_pfn - pfn, + SECTION_ALIGN_UP(pfn + 1) - pfn); + __remove_section(pfn, cur_nr_pages, map_offset, altmap); + map_offset = 0; + } +} + +int set_online_page_callback(online_page_callback_t callback) +{ + int rc = -EINVAL; + + get_online_mems(); + mutex_lock(&online_page_callback_lock); + + if (online_page_callback == generic_online_page) { + online_page_callback = callback; + rc = 0; + } + + mutex_unlock(&online_page_callback_lock); + put_online_mems(); + + return rc; +} +EXPORT_SYMBOL_GPL(set_online_page_callback); + +int restore_online_page_callback(online_page_callback_t callback) +{ + int rc = -EINVAL; + + get_online_mems(); + mutex_lock(&online_page_callback_lock); + + if (online_page_callback == callback) { + online_page_callback = generic_online_page; + rc = 0; + } + + mutex_unlock(&online_page_callback_lock); + put_online_mems(); + + return rc; +} +EXPORT_SYMBOL_GPL(restore_online_page_callback); + +void generic_online_page(struct page *page, unsigned int order) +{ + /* + * Freeing the page with debug_pagealloc enabled will try to unmap it, + * so we should map it first. This is better than introducing a special + * case in page freeing fast path. + */ + debug_pagealloc_map_pages(page, 1 << order); + __free_pages_core(page, order); + totalram_pages_add(1UL << order); +} +EXPORT_SYMBOL_GPL(generic_online_page); + +static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages) +{ + const unsigned long end_pfn = start_pfn + nr_pages; + unsigned long pfn; + + /* + * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might + * decide to not expose all pages to the buddy (e.g., expose them + * later). We account all pages as being online and belonging to this + * zone ("present"). + * When using memmap_on_memory, the range might not be aligned to + * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect + * this and the first chunk to online will be pageblock_nr_pages. + */ + for (pfn = start_pfn; pfn < end_pfn;) { + int order = min(MAX_ORDER - 1UL, __ffs(pfn)); + + (*online_page_callback)(pfn_to_page(pfn), order); + pfn += (1UL << order); + } + + /* mark all involved sections as online */ + online_mem_sections(start_pfn, end_pfn); +} + +/* check which state of node_states will be changed when online memory */ +static void node_states_check_changes_online(unsigned long nr_pages, + struct zone *zone, struct memory_notify *arg) +{ + int nid = zone_to_nid(zone); + + arg->status_change_nid = NUMA_NO_NODE; + arg->status_change_nid_normal = NUMA_NO_NODE; + + if (!node_state(nid, N_MEMORY)) + arg->status_change_nid = nid; + if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY)) + arg->status_change_nid_normal = nid; +} + +static void node_states_set_node(int node, struct memory_notify *arg) +{ + if (arg->status_change_nid_normal >= 0) + node_set_state(node, N_NORMAL_MEMORY); + + if (arg->status_change_nid >= 0) + node_set_state(node, N_MEMORY); +} + +static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn, + unsigned long nr_pages) +{ + unsigned long old_end_pfn = zone_end_pfn(zone); + + if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn) + zone->zone_start_pfn = start_pfn; + + zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn; +} + +static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn, + unsigned long nr_pages) +{ + unsigned long old_end_pfn = pgdat_end_pfn(pgdat); + + if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn) + pgdat->node_start_pfn = start_pfn; + + pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn; + +} + +#ifdef CONFIG_ZONE_DEVICE +static void section_taint_zone_device(unsigned long pfn) +{ + struct mem_section *ms = __pfn_to_section(pfn); + + ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE; +} +#else +static inline void section_taint_zone_device(unsigned long pfn) +{ +} +#endif + +/* + * Associate the pfn range with the given zone, initializing the memmaps + * and resizing the pgdat/zone data to span the added pages. After this + * call, all affected pages are PG_reserved. + * + * All aligned pageblocks are initialized to the specified migratetype + * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related + * zone stats (e.g., nr_isolate_pageblock) are touched. + */ +void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, + unsigned long nr_pages, + struct vmem_altmap *altmap, int migratetype) +{ + struct pglist_data *pgdat = zone->zone_pgdat; + int nid = pgdat->node_id; + + clear_zone_contiguous(zone); + + if (zone_is_empty(zone)) + init_currently_empty_zone(zone, start_pfn, nr_pages); + resize_zone_range(zone, start_pfn, nr_pages); + resize_pgdat_range(pgdat, start_pfn, nr_pages); + + /* + * Subsection population requires care in pfn_to_online_page(). + * Set the taint to enable the slow path detection of + * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE} + * section. + */ + if (zone_is_zone_device(zone)) { + if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION)) + section_taint_zone_device(start_pfn); + if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)) + section_taint_zone_device(start_pfn + nr_pages); + } + + /* + * TODO now we have a visible range of pages which are not associated + * with their zone properly. Not nice but set_pfnblock_flags_mask + * expects the zone spans the pfn range. All the pages in the range + * are reserved so nobody should be touching them so we should be safe + */ + memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0, + MEMINIT_HOTPLUG, altmap, migratetype); + + set_zone_contiguous(zone); +} + +struct auto_movable_stats { + unsigned long kernel_early_pages; + unsigned long movable_pages; +}; + +static void auto_movable_stats_account_zone(struct auto_movable_stats *stats, + struct zone *zone) +{ + if (zone_idx(zone) == ZONE_MOVABLE) { + stats->movable_pages += zone->present_pages; + } else { + stats->kernel_early_pages += zone->present_early_pages; +#ifdef CONFIG_CMA + /* + * CMA pages (never on hotplugged memory) behave like + * ZONE_MOVABLE. + */ + stats->movable_pages += zone->cma_pages; + stats->kernel_early_pages -= zone->cma_pages; +#endif /* CONFIG_CMA */ + } +} +struct auto_movable_group_stats { + unsigned long movable_pages; + unsigned long req_kernel_early_pages; +}; + +static int auto_movable_stats_account_group(struct memory_group *group, + void *arg) +{ + const int ratio = READ_ONCE(auto_movable_ratio); + struct auto_movable_group_stats *stats = arg; + long pages; + + /* + * We don't support modifying the config while the auto-movable online + * policy is already enabled. Just avoid the division by zero below. + */ + if (!ratio) + return 0; + + /* + * Calculate how many early kernel pages this group requires to + * satisfy the configured zone ratio. + */ + pages = group->present_movable_pages * 100 / ratio; + pages -= group->present_kernel_pages; + + if (pages > 0) + stats->req_kernel_early_pages += pages; + stats->movable_pages += group->present_movable_pages; + return 0; +} + +static bool auto_movable_can_online_movable(int nid, struct memory_group *group, + unsigned long nr_pages) +{ + unsigned long kernel_early_pages, movable_pages; + struct auto_movable_group_stats group_stats = {}; + struct auto_movable_stats stats = {}; + pg_data_t *pgdat = NODE_DATA(nid); + struct zone *zone; + int i; + + /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */ + if (nid == NUMA_NO_NODE) { + /* TODO: cache values */ + for_each_populated_zone(zone) + auto_movable_stats_account_zone(&stats, zone); + } else { + for (i = 0; i < MAX_NR_ZONES; i++) { + zone = pgdat->node_zones + i; + if (populated_zone(zone)) + auto_movable_stats_account_zone(&stats, zone); + } + } + + kernel_early_pages = stats.kernel_early_pages; + movable_pages = stats.movable_pages; + + /* + * Kernel memory inside dynamic memory group allows for more MOVABLE + * memory within the same group. Remove the effect of all but the + * current group from the stats. + */ + walk_dynamic_memory_groups(nid, auto_movable_stats_account_group, + group, &group_stats); + if (kernel_early_pages <= group_stats.req_kernel_early_pages) + return false; + kernel_early_pages -= group_stats.req_kernel_early_pages; + movable_pages -= group_stats.movable_pages; + + if (group && group->is_dynamic) + kernel_early_pages += group->present_kernel_pages; + + /* + * Test if we could online the given number of pages to ZONE_MOVABLE + * and still stay in the configured ratio. + */ + movable_pages += nr_pages; + return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100; +} + +/* + * Returns a default kernel memory zone for the given pfn range. + * If no kernel zone covers this pfn range it will automatically go + * to the ZONE_NORMAL. + */ +static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn, + unsigned long nr_pages) +{ + struct pglist_data *pgdat = NODE_DATA(nid); + int zid; + + for (zid = 0; zid < ZONE_NORMAL; zid++) { + struct zone *zone = &pgdat->node_zones[zid]; + + if (zone_intersects(zone, start_pfn, nr_pages)) + return zone; + } + + return &pgdat->node_zones[ZONE_NORMAL]; +} + +/* + * Determine to which zone to online memory dynamically based on user + * configuration and system stats. We care about the following ratio: + * + * MOVABLE : KERNEL + * + * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in + * one of the kernel zones. CMA pages inside one of the kernel zones really + * behaves like ZONE_MOVABLE, so we treat them accordingly. + * + * We don't allow for hotplugged memory in a KERNEL zone to increase the + * amount of MOVABLE memory we can have, so we end up with: + * + * MOVABLE : KERNEL_EARLY + * + * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze + * boot. We base our calculation on KERNEL_EARLY internally, because: + * + * a) Hotplugged memory in one of the kernel zones can sometimes still get + * hotunplugged, especially when hot(un)plugging individual memory blocks. + * There is no coordination across memory devices, therefore "automatic" + * hotunplugging, as implemented in hypervisors, could result in zone + * imbalances. + * b) Early/boot memory in one of the kernel zones can usually not get + * hotunplugged again (e.g., no firmware interface to unplug, fragmented + * with unmovable allocations). While there are corner cases where it might + * still work, it is barely relevant in practice. + * + * Exceptions are dynamic memory groups, which allow for more MOVABLE + * memory within the same memory group -- because in that case, there is + * coordination within the single memory device managed by a single driver. + * + * We rely on "present pages" instead of "managed pages", as the latter is + * highly unreliable and dynamic in virtualized environments, and does not + * consider boot time allocations. For example, memory ballooning adjusts the + * managed pages when inflating/deflating the balloon, and balloon compaction + * can even migrate inflated pages between zones. + * + * Using "present pages" is better but some things to keep in mind are: + * + * a) Some memblock allocations, such as for the crashkernel area, are + * effectively unused by the kernel, yet they account to "present pages". + * Fortunately, these allocations are comparatively small in relevant setups + * (e.g., fraction of system memory). + * b) Some hotplugged memory blocks in virtualized environments, esecially + * hotplugged by virtio-mem, look like they are completely present, however, + * only parts of the memory block are actually currently usable. + * "present pages" is an upper limit that can get reached at runtime. As + * we base our calculations on KERNEL_EARLY, this is not an issue. + */ +static struct zone *auto_movable_zone_for_pfn(int nid, + struct memory_group *group, + unsigned long pfn, + unsigned long nr_pages) +{ + unsigned long online_pages = 0, max_pages, end_pfn; + struct page *page; + + if (!auto_movable_ratio) + goto kernel_zone; + + if (group && !group->is_dynamic) { + max_pages = group->s.max_pages; + online_pages = group->present_movable_pages; + + /* If anything is !MOVABLE online the rest !MOVABLE. */ + if (group->present_kernel_pages) + goto kernel_zone; + } else if (!group || group->d.unit_pages == nr_pages) { + max_pages = nr_pages; + } else { + max_pages = group->d.unit_pages; + /* + * Take a look at all online sections in the current unit. + * We can safely assume that all pages within a section belong + * to the same zone, because dynamic memory groups only deal + * with hotplugged memory. + */ + pfn = ALIGN_DOWN(pfn, group->d.unit_pages); + end_pfn = pfn + group->d.unit_pages; + for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { + page = pfn_to_online_page(pfn); + if (!page) + continue; + /* If anything is !MOVABLE online the rest !MOVABLE. */ + if (!is_zone_movable_page(page)) + goto kernel_zone; + online_pages += PAGES_PER_SECTION; + } + } + + /* + * Online MOVABLE if we could *currently* online all remaining parts + * MOVABLE. We expect to (add+) online them immediately next, so if + * nobody interferes, all will be MOVABLE if possible. + */ + nr_pages = max_pages - online_pages; + if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages)) + goto kernel_zone; + +#ifdef CONFIG_NUMA + if (auto_movable_numa_aware && + !auto_movable_can_online_movable(nid, group, nr_pages)) + goto kernel_zone; +#endif /* CONFIG_NUMA */ + + return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; +kernel_zone: + return default_kernel_zone_for_pfn(nid, pfn, nr_pages); +} + +static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn, + unsigned long nr_pages) +{ + struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn, + nr_pages); + struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; + bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages); + bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages); + + /* + * We inherit the existing zone in a simple case where zones do not + * overlap in the given range + */ + if (in_kernel ^ in_movable) + return (in_kernel) ? kernel_zone : movable_zone; + + /* + * If the range doesn't belong to any zone or two zones overlap in the + * given range then we use movable zone only if movable_node is + * enabled because we always online to a kernel zone by default. + */ + return movable_node_enabled ? movable_zone : kernel_zone; +} + +struct zone *zone_for_pfn_range(int online_type, int nid, + struct memory_group *group, unsigned long start_pfn, + unsigned long nr_pages) +{ + if (online_type == MMOP_ONLINE_KERNEL) + return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages); + + if (online_type == MMOP_ONLINE_MOVABLE) + return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE]; + + if (online_policy == ONLINE_POLICY_AUTO_MOVABLE) + return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages); + + return default_zone_for_pfn(nid, start_pfn, nr_pages); +} + +/* + * This function should only be called by memory_block_{online,offline}, + * and {online,offline}_pages. + */ +void adjust_present_page_count(struct page *page, struct memory_group *group, + long nr_pages) +{ + struct zone *zone = page_zone(page); + const bool movable = zone_idx(zone) == ZONE_MOVABLE; + + /* + * We only support onlining/offlining/adding/removing of complete + * memory blocks; therefore, either all is either early or hotplugged. + */ + if (early_section(__pfn_to_section(page_to_pfn(page)))) + zone->present_early_pages += nr_pages; + zone->present_pages += nr_pages; + zone->zone_pgdat->node_present_pages += nr_pages; + + if (group && movable) + group->present_movable_pages += nr_pages; + else if (group && !movable) + group->present_kernel_pages += nr_pages; +} + +int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages, + struct zone *zone) +{ + unsigned long end_pfn = pfn + nr_pages; + int ret, i; + + ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); + if (ret) + return ret; + + move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE); + + for (i = 0; i < nr_pages; i++) + SetPageVmemmapSelfHosted(pfn_to_page(pfn + i)); + + /* + * It might be that the vmemmap_pages fully span sections. If that is + * the case, mark those sections online here as otherwise they will be + * left offline. + */ + if (nr_pages >= PAGES_PER_SECTION) + online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); + + return ret; +} + +void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages) +{ + unsigned long end_pfn = pfn + nr_pages; + + /* + * It might be that the vmemmap_pages fully span sections. If that is + * the case, mark those sections offline here as otherwise they will be + * left online. + */ + if (nr_pages >= PAGES_PER_SECTION) + offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION)); + + /* + * The pages associated with this vmemmap have been offlined, so + * we can reset its state here. + */ + remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages); + kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); +} + +/* + * Must be called with mem_hotplug_lock in write mode. + */ +int __ref online_pages(unsigned long pfn, unsigned long nr_pages, + struct zone *zone, struct memory_group *group) +{ + unsigned long flags; + int need_zonelists_rebuild = 0; + const int nid = zone_to_nid(zone); + int ret; + struct memory_notify arg; + + /* + * {on,off}lining is constrained to full memory sections (or more + * precisely to memory blocks from the user space POV). + * memmap_on_memory is an exception because it reserves initial part + * of the physical memory space for vmemmaps. That space is pageblock + * aligned. + */ + if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) || + !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION))) + return -EINVAL; + + + /* associate pfn range with the zone */ + move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE); + + arg.start_pfn = pfn; + arg.nr_pages = nr_pages; + node_states_check_changes_online(nr_pages, zone, &arg); + + ret = memory_notify(MEM_GOING_ONLINE, &arg); + ret = notifier_to_errno(ret); + if (ret) + goto failed_addition; + + /* + * Fixup the number of isolated pageblocks before marking the sections + * onlining, such that undo_isolate_page_range() works correctly. + */ + spin_lock_irqsave(&zone->lock, flags); + zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages; + spin_unlock_irqrestore(&zone->lock, flags); + + /* + * If this zone is not populated, then it is not in zonelist. + * This means the page allocator ignores this zone. + * So, zonelist must be updated after online. + */ + if (!populated_zone(zone)) { + need_zonelists_rebuild = 1; + setup_zone_pageset(zone); + } + + online_pages_range(pfn, nr_pages); + adjust_present_page_count(pfn_to_page(pfn), group, nr_pages); + + node_states_set_node(nid, &arg); + if (need_zonelists_rebuild) + build_all_zonelists(NULL); + + /* Basic onlining is complete, allow allocation of onlined pages. */ + undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE); + + /* + * Freshly onlined pages aren't shuffled (e.g., all pages are placed to + * the tail of the freelist when undoing isolation). Shuffle the whole + * zone to make sure the just onlined pages are properly distributed + * across the whole freelist - to create an initial shuffle. + */ + shuffle_zone(zone); + + /* reinitialise watermarks and update pcp limits */ + init_per_zone_wmark_min(); + + kswapd_run(nid); + kcompactd_run(nid); + + writeback_set_ratelimit(); + + memory_notify(MEM_ONLINE, &arg); + return 0; + +failed_addition: + pr_debug("online_pages [mem %#010llx-%#010llx] failed\n", + (unsigned long long) pfn << PAGE_SHIFT, + (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1); + memory_notify(MEM_CANCEL_ONLINE, &arg); + remove_pfn_range_from_zone(zone, pfn, nr_pages); + return ret; +} + +static void reset_node_present_pages(pg_data_t *pgdat) +{ + struct zone *z; + + for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) + z->present_pages = 0; + + pgdat->node_present_pages = 0; +} + +/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ +static pg_data_t __ref *hotadd_init_pgdat(int nid) +{ + struct pglist_data *pgdat; + + /* + * NODE_DATA is preallocated (free_area_init) but its internal + * state is not allocated completely. Add missing pieces. + * Completely offline nodes stay around and they just need + * reintialization. + */ + pgdat = NODE_DATA(nid); + + /* init node's zones as empty zones, we don't have any present pages.*/ + free_area_init_core_hotplug(pgdat); + + /* + * The node we allocated has no zone fallback lists. For avoiding + * to access not-initialized zonelist, build here. + */ + build_all_zonelists(pgdat); + + /* + * When memory is hot-added, all the memory is in offline state. So + * clear all zones' present_pages because they will be updated in + * online_pages() and offline_pages(). + * TODO: should be in free_area_init_core_hotplug? + */ + reset_node_managed_pages(pgdat); + reset_node_present_pages(pgdat); + + return pgdat; +} + +/* + * __try_online_node - online a node if offlined + * @nid: the node ID + * @set_node_online: Whether we want to online the node + * called by cpu_up() to online a node without onlined memory. + * + * Returns: + * 1 -> a new node has been allocated + * 0 -> the node is already online + * -ENOMEM -> the node could not be allocated + */ +static int __try_online_node(int nid, bool set_node_online) +{ + pg_data_t *pgdat; + int ret = 1; + + if (node_online(nid)) + return 0; + + pgdat = hotadd_init_pgdat(nid); + if (!pgdat) { + pr_err("Cannot online node %d due to NULL pgdat\n", nid); + ret = -ENOMEM; + goto out; + } + + if (set_node_online) { + node_set_online(nid); + ret = register_one_node(nid); + BUG_ON(ret); + } +out: + return ret; +} + +/* + * Users of this function always want to online/register the node + */ +int try_online_node(int nid) +{ + int ret; + + mem_hotplug_begin(); + ret = __try_online_node(nid, true); + mem_hotplug_done(); + return ret; +} + +static int check_hotplug_memory_range(u64 start, u64 size) +{ + /* memory range must be block size aligned */ + if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) || + !IS_ALIGNED(size, memory_block_size_bytes())) { + pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx", + memory_block_size_bytes(), start, size); + return -EINVAL; + } + + return 0; +} + +static int online_memory_block(struct memory_block *mem, void *arg) +{ + mem->online_type = mhp_default_online_type; + return device_online(&mem->dev); +} + +bool mhp_supports_memmap_on_memory(unsigned long size) +{ + unsigned long nr_vmemmap_pages = size / PAGE_SIZE; + unsigned long vmemmap_size = nr_vmemmap_pages * sizeof(struct page); + unsigned long remaining_size = size - vmemmap_size; + + /* + * Besides having arch support and the feature enabled at runtime, we + * need a few more assumptions to hold true: + * + * a) We span a single memory block: memory onlining/offlinin;g happens + * in memory block granularity. We don't want the vmemmap of online + * memory blocks to reside on offline memory blocks. In the future, + * we might want to support variable-sized memory blocks to make the + * feature more versatile. + * + * b) The vmemmap pages span complete PMDs: We don't want vmemmap code + * to populate memory from the altmap for unrelated parts (i.e., + * other memory blocks) + * + * c) The vmemmap pages (and thereby the pages that will be exposed to + * the buddy) have to cover full pageblocks: memory onlining/offlining + * code requires applicable ranges to be page-aligned, for example, to + * set the migratetypes properly. + * + * TODO: Although we have a check here to make sure that vmemmap pages + * fully populate a PMD, it is not the right place to check for + * this. A much better solution involves improving vmemmap code + * to fallback to base pages when trying to populate vmemmap using + * altmap as an alternative source of memory, and we do not exactly + * populate a single PMD. + */ + return mhp_memmap_on_memory() && + size == memory_block_size_bytes() && + IS_ALIGNED(vmemmap_size, PMD_SIZE) && + IS_ALIGNED(remaining_size, (pageblock_nr_pages << PAGE_SHIFT)); +} + +/* + * NOTE: The caller must call lock_device_hotplug() to serialize hotplug + * and online/offline operations (triggered e.g. by sysfs). + * + * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG + */ +int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags) +{ + struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) }; + enum memblock_flags memblock_flags = MEMBLOCK_NONE; + struct vmem_altmap mhp_altmap = {}; + struct memory_group *group = NULL; + u64 start, size; + bool new_node = false; + int ret; + + start = res->start; + size = resource_size(res); + + ret = check_hotplug_memory_range(start, size); + if (ret) + return ret; + + if (mhp_flags & MHP_NID_IS_MGID) { + group = memory_group_find_by_id(nid); + if (!group) + return -EINVAL; + nid = group->nid; + } + + if (!node_possible(nid)) { + WARN(1, "node %d was absent from the node_possible_map\n", nid); + return -EINVAL; + } + + mem_hotplug_begin(); + + if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { + if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED) + memblock_flags = MEMBLOCK_DRIVER_MANAGED; + ret = memblock_add_node(start, size, nid, memblock_flags); + if (ret) + goto error_mem_hotplug_end; + } + + ret = __try_online_node(nid, false); + if (ret < 0) + goto error; + new_node = ret; + + /* + * Self hosted memmap array + */ + if (mhp_flags & MHP_MEMMAP_ON_MEMORY) { + if (!mhp_supports_memmap_on_memory(size)) { + ret = -EINVAL; + goto error; + } + mhp_altmap.free = PHYS_PFN(size); + mhp_altmap.base_pfn = PHYS_PFN(start); + params.altmap = &mhp_altmap; + } + + /* call arch's memory hotadd */ + ret = arch_add_memory(nid, start, size, ¶ms); + if (ret < 0) + goto error; + + /* create memory block devices after memory was added */ + ret = create_memory_block_devices(start, size, mhp_altmap.alloc, + group); + if (ret) { + arch_remove_memory(start, size, params.altmap); + goto error; + } + + if (new_node) { + /* If sysfs file of new node can't be created, cpu on the node + * can't be hot-added. There is no rollback way now. + * So, check by BUG_ON() to catch it reluctantly.. + * We online node here. We can't roll back from here. + */ + node_set_online(nid); + ret = __register_one_node(nid); + BUG_ON(ret); + } + + register_memory_blocks_under_node(nid, PFN_DOWN(start), + PFN_UP(start + size - 1), + MEMINIT_HOTPLUG); + + /* create new memmap entry */ + if (!strcmp(res->name, "System RAM")) + firmware_map_add_hotplug(start, start + size, "System RAM"); + + /* device_online() will take the lock when calling online_pages() */ + mem_hotplug_done(); + + /* + * In case we're allowed to merge the resource, flag it and trigger + * merging now that adding succeeded. + */ + if (mhp_flags & MHP_MERGE_RESOURCE) + merge_system_ram_resource(res); + + /* online pages if requested */ + if (mhp_default_online_type != MMOP_OFFLINE) + walk_memory_blocks(start, size, NULL, online_memory_block); + + return ret; +error: + if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) + memblock_remove(start, size); +error_mem_hotplug_end: + mem_hotplug_done(); + return ret; +} + +/* requires device_hotplug_lock, see add_memory_resource() */ +int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) +{ + struct resource *res; + int ret; + + res = register_memory_resource(start, size, "System RAM"); + if (IS_ERR(res)) + return PTR_ERR(res); + + ret = add_memory_resource(nid, res, mhp_flags); + if (ret < 0) + release_memory_resource(res); + return ret; +} + +int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags) +{ + int rc; + + lock_device_hotplug(); + rc = __add_memory(nid, start, size, mhp_flags); + unlock_device_hotplug(); + + return rc; +} +EXPORT_SYMBOL_GPL(add_memory); + +/* + * Add special, driver-managed memory to the system as system RAM. Such + * memory is not exposed via the raw firmware-provided memmap as system + * RAM, instead, it is detected and added by a driver - during cold boot, + * after a reboot, and after kexec. + * + * Reasons why this memory should not be used for the initial memmap of a + * kexec kernel or for placing kexec images: + * - The booting kernel is in charge of determining how this memory will be + * used (e.g., use persistent memory as system RAM) + * - Coordination with a hypervisor is required before this memory + * can be used (e.g., inaccessible parts). + * + * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided + * memory map") are created. Also, the created memory resource is flagged + * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case + * this memory as well (esp., not place kexec images onto it). + * + * The resource_name (visible via /proc/iomem) has to have the format + * "System RAM ($DRIVER)". + */ +int add_memory_driver_managed(int nid, u64 start, u64 size, + const char *resource_name, mhp_t mhp_flags) +{ + struct resource *res; + int rc; + + if (!resource_name || + strstr(resource_name, "System RAM (") != resource_name || + resource_name[strlen(resource_name) - 1] != ')') + return -EINVAL; + + lock_device_hotplug(); + + res = register_memory_resource(start, size, resource_name); + if (IS_ERR(res)) { + rc = PTR_ERR(res); + goto out_unlock; + } + + rc = add_memory_resource(nid, res, mhp_flags); + if (rc < 0) + release_memory_resource(res); + +out_unlock: + unlock_device_hotplug(); + return rc; +} +EXPORT_SYMBOL_GPL(add_memory_driver_managed); + +/* + * Platforms should define arch_get_mappable_range() that provides + * maximum possible addressable physical memory range for which the + * linear mapping could be created. The platform returned address + * range must adhere to these following semantics. + * + * - range.start <= range.end + * - Range includes both end points [range.start..range.end] + * + * There is also a fallback definition provided here, allowing the + * entire possible physical address range in case any platform does + * not define arch_get_mappable_range(). + */ +struct range __weak arch_get_mappable_range(void) +{ + struct range mhp_range = { + .start = 0UL, + .end = -1ULL, + }; + return mhp_range; +} + +struct range mhp_get_pluggable_range(bool need_mapping) +{ + const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1; + struct range mhp_range; + + if (need_mapping) { + mhp_range = arch_get_mappable_range(); + if (mhp_range.start > max_phys) { + mhp_range.start = 0; + mhp_range.end = 0; + } + mhp_range.end = min_t(u64, mhp_range.end, max_phys); + } else { + mhp_range.start = 0; + mhp_range.end = max_phys; + } + return mhp_range; +} +EXPORT_SYMBOL_GPL(mhp_get_pluggable_range); + +bool mhp_range_allowed(u64 start, u64 size, bool need_mapping) +{ + struct range mhp_range = mhp_get_pluggable_range(need_mapping); + u64 end = start + size; + + if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end) + return true; + + pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n", + start, end, mhp_range.start, mhp_range.end); + return false; +} + +#ifdef CONFIG_MEMORY_HOTREMOVE +/* + * Scan pfn range [start,end) to find movable/migratable pages (LRU pages, + * non-lru movable pages and hugepages). Will skip over most unmovable + * pages (esp., pages that can be skipped when offlining), but bail out on + * definitely unmovable pages. + * + * Returns: + * 0 in case a movable page is found and movable_pfn was updated. + * -ENOENT in case no movable page was found. + * -EBUSY in case a definitely unmovable page was found. + */ +static int scan_movable_pages(unsigned long start, unsigned long end, + unsigned long *movable_pfn) +{ + unsigned long pfn; + + for (pfn = start; pfn < end; pfn++) { + struct page *page, *head; + unsigned long skip; + + if (!pfn_valid(pfn)) + continue; + page = pfn_to_page(pfn); + if (PageLRU(page)) + goto found; + if (__PageMovable(page)) + goto found; + + /* + * PageOffline() pages that are not marked __PageMovable() and + * have a reference count > 0 (after MEM_GOING_OFFLINE) are + * definitely unmovable. If their reference count would be 0, + * they could at least be skipped when offlining memory. + */ + if (PageOffline(page) && page_count(page)) + return -EBUSY; + + if (!PageHuge(page)) + continue; + head = compound_head(page); + /* + * This test is racy as we hold no reference or lock. The + * hugetlb page could have been free'ed and head is no longer + * a hugetlb page before the following check. In such unlikely + * cases false positives and negatives are possible. Calling + * code must deal with these scenarios. + */ + if (HPageMigratable(head)) + goto found; + skip = compound_nr(head) - (pfn - page_to_pfn(head)); + pfn += skip - 1; + } + return -ENOENT; +found: + *movable_pfn = pfn; + return 0; +} + +static int +do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) +{ + unsigned long pfn; + struct page *page, *head; + int ret = 0; + LIST_HEAD(source); + static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + + for (pfn = start_pfn; pfn < end_pfn; pfn++) { + struct folio *folio; + + if (!pfn_valid(pfn)) + continue; + page = pfn_to_page(pfn); + folio = page_folio(page); + head = &folio->page; + + if (PageHuge(page)) { + pfn = page_to_pfn(head) + compound_nr(head) - 1; + isolate_hugetlb(head, &source); + continue; + } else if (PageTransHuge(page)) + pfn = page_to_pfn(head) + thp_nr_pages(page) - 1; + + /* + * HWPoison pages have elevated reference counts so the migration would + * fail on them. It also doesn't make any sense to migrate them in the + * first place. Still try to unmap such a page in case it is still mapped + * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep + * the unmap as the catch all safety net). + */ + if (PageHWPoison(page)) { + if (WARN_ON(folio_test_lru(folio))) + folio_isolate_lru(folio); + if (folio_mapped(folio)) + try_to_unmap(folio, TTU_IGNORE_MLOCK); + continue; + } + + if (!get_page_unless_zero(page)) + continue; + /* + * We can skip free pages. And we can deal with pages on + * LRU and non-lru movable pages. + */ + if (PageLRU(page)) + ret = isolate_lru_page(page); + else + ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE); + if (!ret) { /* Success */ + list_add_tail(&page->lru, &source); + if (!__PageMovable(page)) + inc_node_page_state(page, NR_ISOLATED_ANON + + page_is_file_lru(page)); + + } else { + if (__ratelimit(&migrate_rs)) { + pr_warn("failed to isolate pfn %lx\n", pfn); + dump_page(page, "isolation failed"); + } + } + put_page(page); + } + if (!list_empty(&source)) { + nodemask_t nmask = node_states[N_MEMORY]; + struct migration_target_control mtc = { + .nmask = &nmask, + .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, + }; + + /* + * We have checked that migration range is on a single zone so + * we can use the nid of the first page to all the others. + */ + mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru)); + + /* + * try to allocate from a different node but reuse this node + * if there are no other online nodes to be used (e.g. we are + * offlining a part of the only existing node) + */ + node_clear(mtc.nid, nmask); + if (nodes_empty(nmask)) + node_set(mtc.nid, nmask); + ret = migrate_pages(&source, alloc_migration_target, NULL, + (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL); + if (ret) { + list_for_each_entry(page, &source, lru) { + if (__ratelimit(&migrate_rs)) { + pr_warn("migrating pfn %lx failed ret:%d\n", + page_to_pfn(page), ret); + dump_page(page, "migration failure"); + } + } + putback_movable_pages(&source); + } + } + + return ret; +} + +static int __init cmdline_parse_movable_node(char *p) +{ + movable_node_enabled = true; + return 0; +} +early_param("movable_node", cmdline_parse_movable_node); + +/* check which state of node_states will be changed when offline memory */ +static void node_states_check_changes_offline(unsigned long nr_pages, + struct zone *zone, struct memory_notify *arg) +{ + struct pglist_data *pgdat = zone->zone_pgdat; + unsigned long present_pages = 0; + enum zone_type zt; + + arg->status_change_nid = NUMA_NO_NODE; + arg->status_change_nid_normal = NUMA_NO_NODE; + + /* + * Check whether node_states[N_NORMAL_MEMORY] will be changed. + * If the memory to be offline is within the range + * [0..ZONE_NORMAL], and it is the last present memory there, + * the zones in that range will become empty after the offlining, + * thus we can determine that we need to clear the node from + * node_states[N_NORMAL_MEMORY]. + */ + for (zt = 0; zt <= ZONE_NORMAL; zt++) + present_pages += pgdat->node_zones[zt].present_pages; + if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages) + arg->status_change_nid_normal = zone_to_nid(zone); + + /* + * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM + * does not apply as we don't support 32bit. + * Here we count the possible pages from ZONE_MOVABLE. + * If after having accounted all the pages, we see that the nr_pages + * to be offlined is over or equal to the accounted pages, + * we know that the node will become empty, and so, we can clear + * it for N_MEMORY as well. + */ + present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages; + + if (nr_pages >= present_pages) + arg->status_change_nid = zone_to_nid(zone); +} + +static void node_states_clear_node(int node, struct memory_notify *arg) +{ + if (arg->status_change_nid_normal >= 0) + node_clear_state(node, N_NORMAL_MEMORY); + + if (arg->status_change_nid >= 0) + node_clear_state(node, N_MEMORY); +} + +static int count_system_ram_pages_cb(unsigned long start_pfn, + unsigned long nr_pages, void *data) +{ + unsigned long *nr_system_ram_pages = data; + + *nr_system_ram_pages += nr_pages; + return 0; +} + +/* + * Must be called with mem_hotplug_lock in write mode. + */ +int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages, + struct zone *zone, struct memory_group *group) +{ + const unsigned long end_pfn = start_pfn + nr_pages; + unsigned long pfn, system_ram_pages = 0; + const int node = zone_to_nid(zone); + unsigned long flags; + struct memory_notify arg; + char *reason; + int ret; + + /* + * {on,off}lining is constrained to full memory sections (or more + * precisely to memory blocks from the user space POV). + * memmap_on_memory is an exception because it reserves initial part + * of the physical memory space for vmemmaps. That space is pageblock + * aligned. + */ + if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) || + !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))) + return -EINVAL; + + /* + * Don't allow to offline memory blocks that contain holes. + * Consequently, memory blocks with holes can never get onlined + * via the hotplug path - online_pages() - as hotplugged memory has + * no holes. This way, we e.g., don't have to worry about marking + * memory holes PG_reserved, don't need pfn_valid() checks, and can + * avoid using walk_system_ram_range() later. + */ + walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages, + count_system_ram_pages_cb); + if (system_ram_pages != nr_pages) { + ret = -EINVAL; + reason = "memory holes"; + goto failed_removal; + } + + /* + * We only support offlining of memory blocks managed by a single zone, + * checked by calling code. This is just a sanity check that we might + * want to remove in the future. + */ + if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone || + page_zone(pfn_to_page(end_pfn - 1)) != zone)) { + ret = -EINVAL; + reason = "multizone range"; + goto failed_removal; + } + + /* + * Disable pcplists so that page isolation cannot race with freeing + * in a way that pages from isolated pageblock are left on pcplists. + */ + zone_pcp_disable(zone); + lru_cache_disable(); + + /* set above range as isolated */ + ret = start_isolate_page_range(start_pfn, end_pfn, + MIGRATE_MOVABLE, + MEMORY_OFFLINE | REPORT_FAILURE, + GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL); + if (ret) { + reason = "failure to isolate range"; + goto failed_removal_pcplists_disabled; + } + + arg.start_pfn = start_pfn; + arg.nr_pages = nr_pages; + node_states_check_changes_offline(nr_pages, zone, &arg); + + ret = memory_notify(MEM_GOING_OFFLINE, &arg); + ret = notifier_to_errno(ret); + if (ret) { + reason = "notifier failure"; + goto failed_removal_isolated; + } + + do { + pfn = start_pfn; + do { + if (signal_pending(current)) { + ret = -EINTR; + reason = "signal backoff"; + goto failed_removal_isolated; + } + + cond_resched(); + + ret = scan_movable_pages(pfn, end_pfn, &pfn); + if (!ret) { + /* + * TODO: fatal migration failures should bail + * out + */ + do_migrate_range(pfn, end_pfn); + } + } while (!ret); + + if (ret != -ENOENT) { + reason = "unmovable page"; + goto failed_removal_isolated; + } + + /* + * Dissolve free hugepages in the memory block before doing + * offlining actually in order to make hugetlbfs's object + * counting consistent. + */ + ret = dissolve_free_huge_pages(start_pfn, end_pfn); + if (ret) { + reason = "failure to dissolve huge pages"; + goto failed_removal_isolated; + } + + ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE); + + } while (ret); + + /* Mark all sections offline and remove free pages from the buddy. */ + __offline_isolated_pages(start_pfn, end_pfn); + pr_debug("Offlined Pages %ld\n", nr_pages); + + /* + * The memory sections are marked offline, and the pageblock flags + * effectively stale; nobody should be touching them. Fixup the number + * of isolated pageblocks, memory onlining will properly revert this. + */ + spin_lock_irqsave(&zone->lock, flags); + zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages; + spin_unlock_irqrestore(&zone->lock, flags); + + lru_cache_enable(); + zone_pcp_enable(zone); + + /* removal success */ + adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages); + adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages); + + /* reinitialise watermarks and update pcp limits */ + init_per_zone_wmark_min(); + + if (!populated_zone(zone)) { + zone_pcp_reset(zone); + build_all_zonelists(NULL); + } + + node_states_clear_node(node, &arg); + if (arg.status_change_nid >= 0) { + kcompactd_stop(node); + kswapd_stop(node); + } + + writeback_set_ratelimit(); + + memory_notify(MEM_OFFLINE, &arg); + remove_pfn_range_from_zone(zone, start_pfn, nr_pages); + return 0; + +failed_removal_isolated: + /* pushback to free area */ + undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); + memory_notify(MEM_CANCEL_OFFLINE, &arg); +failed_removal_pcplists_disabled: + lru_cache_enable(); + zone_pcp_enable(zone); +failed_removal: + pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n", + (unsigned long long) start_pfn << PAGE_SHIFT, + ((unsigned long long) end_pfn << PAGE_SHIFT) - 1, + reason); + return ret; +} + +static int check_memblock_offlined_cb(struct memory_block *mem, void *arg) +{ + int *nid = arg; + + *nid = mem->nid; + if (unlikely(mem->state != MEM_OFFLINE)) { + phys_addr_t beginpa, endpa; + + beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)); + endpa = beginpa + memory_block_size_bytes() - 1; + pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n", + &beginpa, &endpa); + + return -EBUSY; + } + return 0; +} + +static int get_nr_vmemmap_pages_cb(struct memory_block *mem, void *arg) +{ + /* + * If not set, continue with the next block. + */ + return mem->nr_vmemmap_pages; +} + +static int check_cpu_on_node(int nid) +{ + int cpu; + + for_each_present_cpu(cpu) { + if (cpu_to_node(cpu) == nid) + /* + * the cpu on this node isn't removed, and we can't + * offline this node. + */ + return -EBUSY; + } + + return 0; +} + +static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg) +{ + int nid = *(int *)arg; + + /* + * If a memory block belongs to multiple nodes, the stored nid is not + * reliable. However, such blocks are always online (e.g., cannot get + * offlined) and, therefore, are still spanned by the node. + */ + return mem->nid == nid ? -EEXIST : 0; +} + +/** + * try_offline_node + * @nid: the node ID + * + * Offline a node if all memory sections and cpus of the node are removed. + * + * NOTE: The caller must call lock_device_hotplug() to serialize hotplug + * and online/offline operations before this call. + */ +void try_offline_node(int nid) +{ + int rc; + + /* + * If the node still spans pages (especially ZONE_DEVICE), don't + * offline it. A node spans memory after move_pfn_range_to_zone(), + * e.g., after the memory block was onlined. + */ + if (node_spanned_pages(nid)) + return; + + /* + * Especially offline memory blocks might not be spanned by the + * node. They will get spanned by the node once they get onlined. + * However, they link to the node in sysfs and can get onlined later. + */ + rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb); + if (rc) + return; + + if (check_cpu_on_node(nid)) + return; + + /* + * all memory/cpu of this node are removed, we can offline this + * node now. + */ + node_set_offline(nid); + unregister_one_node(nid); +} +EXPORT_SYMBOL(try_offline_node); + +static int __ref try_remove_memory(u64 start, u64 size) +{ + struct vmem_altmap mhp_altmap = {}; + struct vmem_altmap *altmap = NULL; + unsigned long nr_vmemmap_pages; + int rc = 0, nid = NUMA_NO_NODE; + + BUG_ON(check_hotplug_memory_range(start, size)); + + /* + * All memory blocks must be offlined before removing memory. Check + * whether all memory blocks in question are offline and return error + * if this is not the case. + * + * While at it, determine the nid. Note that if we'd have mixed nodes, + * we'd only try to offline the last determined one -- which is good + * enough for the cases we care about. + */ + rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb); + if (rc) + return rc; + + /* + * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in + * the same granularity it was added - a single memory block. + */ + if (mhp_memmap_on_memory()) { + nr_vmemmap_pages = walk_memory_blocks(start, size, NULL, + get_nr_vmemmap_pages_cb); + if (nr_vmemmap_pages) { + if (size != memory_block_size_bytes()) { + pr_warn("Refuse to remove %#llx - %#llx," + "wrong granularity\n", + start, start + size); + return -EINVAL; + } + + /* + * Let remove_pmd_table->free_hugepage_table do the + * right thing if we used vmem_altmap when hot-adding + * the range. + */ + mhp_altmap.alloc = nr_vmemmap_pages; + altmap = &mhp_altmap; + } + } + + /* remove memmap entry */ + firmware_map_remove(start, start + size, "System RAM"); + + /* + * Memory block device removal under the device_hotplug_lock is + * a barrier against racing online attempts. + */ + remove_memory_block_devices(start, size); + + mem_hotplug_begin(); + + arch_remove_memory(start, size, altmap); + + if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) { + memblock_phys_free(start, size); + memblock_remove(start, size); + } + + release_mem_region_adjustable(start, size); + + if (nid != NUMA_NO_NODE) + try_offline_node(nid); + + mem_hotplug_done(); + return 0; +} + +/** + * __remove_memory - Remove memory if every memory block is offline + * @start: physical address of the region to remove + * @size: size of the region to remove + * + * NOTE: The caller must call lock_device_hotplug() to serialize hotplug + * and online/offline operations before this call, as required by + * try_offline_node(). + */ +void __remove_memory(u64 start, u64 size) +{ + + /* + * trigger BUG() if some memory is not offlined prior to calling this + * function + */ + if (try_remove_memory(start, size)) + BUG(); +} + +/* + * Remove memory if every memory block is offline, otherwise return -EBUSY is + * some memory is not offline + */ +int remove_memory(u64 start, u64 size) +{ + int rc; + + lock_device_hotplug(); + rc = try_remove_memory(start, size); + unlock_device_hotplug(); + + return rc; +} +EXPORT_SYMBOL_GPL(remove_memory); + +static int try_offline_memory_block(struct memory_block *mem, void *arg) +{ + uint8_t online_type = MMOP_ONLINE_KERNEL; + uint8_t **online_types = arg; + struct page *page; + int rc; + + /* + * Sense the online_type via the zone of the memory block. Offlining + * with multiple zones within one memory block will be rejected + * by offlining code ... so we don't care about that. + */ + page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr)); + if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE) + online_type = MMOP_ONLINE_MOVABLE; + + rc = device_offline(&mem->dev); + /* + * Default is MMOP_OFFLINE - change it only if offlining succeeded, + * so try_reonline_memory_block() can do the right thing. + */ + if (!rc) + **online_types = online_type; + + (*online_types)++; + /* Ignore if already offline. */ + return rc < 0 ? rc : 0; +} + +static int try_reonline_memory_block(struct memory_block *mem, void *arg) +{ + uint8_t **online_types = arg; + int rc; + + if (**online_types != MMOP_OFFLINE) { + mem->online_type = **online_types; + rc = device_online(&mem->dev); + if (rc < 0) + pr_warn("%s: Failed to re-online memory: %d", + __func__, rc); + } + + /* Continue processing all remaining memory blocks. */ + (*online_types)++; + return 0; +} + +/* + * Try to offline and remove memory. Might take a long time to finish in case + * memory is still in use. Primarily useful for memory devices that logically + * unplugged all memory (so it's no longer in use) and want to offline + remove + * that memory. + */ +int offline_and_remove_memory(u64 start, u64 size) +{ + const unsigned long mb_count = size / memory_block_size_bytes(); + uint8_t *online_types, *tmp; + int rc; + + if (!IS_ALIGNED(start, memory_block_size_bytes()) || + !IS_ALIGNED(size, memory_block_size_bytes()) || !size) + return -EINVAL; + + /* + * We'll remember the old online type of each memory block, so we can + * try to revert whatever we did when offlining one memory block fails + * after offlining some others succeeded. + */ + online_types = kmalloc_array(mb_count, sizeof(*online_types), + GFP_KERNEL); + if (!online_types) + return -ENOMEM; + /* + * Initialize all states to MMOP_OFFLINE, so when we abort processing in + * try_offline_memory_block(), we'll skip all unprocessed blocks in + * try_reonline_memory_block(). + */ + memset(online_types, MMOP_OFFLINE, mb_count); + + lock_device_hotplug(); + + tmp = online_types; + rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block); + + /* + * In case we succeeded to offline all memory, remove it. + * This cannot fail as it cannot get onlined in the meantime. + */ + if (!rc) { + rc = try_remove_memory(start, size); + if (rc) + pr_err("%s: Failed to remove memory: %d", __func__, rc); + } + + /* + * Rollback what we did. While memory onlining might theoretically fail + * (nacked by a notifier), it barely ever happens. + */ + if (rc) { + tmp = online_types; + walk_memory_blocks(start, size, &tmp, + try_reonline_memory_block); + } + unlock_device_hotplug(); + + kfree(online_types); + return rc; +} +EXPORT_SYMBOL_GPL(offline_and_remove_memory); +#endif /* CONFIG_MEMORY_HOTREMOVE */ |