// SPDX-License-Identifier: GPL-2.0-only /* * linux/mm/memory_hotplug.c * * Copyright (C) */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "internal.h" #include "shuffle.h" /* * 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 bool memhp_auto_online; #else bool memhp_auto_online = true; #endif EXPORT_SYMBOL_GPL(memhp_auto_online); static int __init setup_memhp_default_state(char *str) { if (!strcmp(str, "online")) memhp_auto_online = true; else if (!strcmp(str, "offline")) memhp_auto_online = false; 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) { struct resource *res; unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; char *resource_name = "System RAM"; if (start + size > max_mem_size) 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); } #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE void get_page_bootmem(unsigned long info, struct page *page, unsigned long type) { page->freelist = (void *)type; SetPagePrivate(page); set_page_private(page, info); page_ref_inc(page); } void put_page_bootmem(struct page *page) { unsigned long type; type = (unsigned long) page->freelist; BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE); if (page_ref_dec_return(page) == 1) { page->freelist = NULL; ClearPagePrivate(page); set_page_private(page, 0); INIT_LIST_HEAD(&page->lru); free_reserved_page(page); } } #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE #ifndef CONFIG_SPARSEMEM_VMEMMAP static void register_page_bootmem_info_section(unsigned long start_pfn) { unsigned long mapsize, section_nr, i; struct mem_section *ms; struct page *page, *memmap; struct mem_section_usage *usage; section_nr = pfn_to_section_nr(start_pfn); ms = __nr_to_section(section_nr); /* Get section's memmap address */ memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); /* * Get page for the memmap's phys address * XXX: need more consideration for sparse_vmemmap... */ page = virt_to_page(memmap); mapsize = sizeof(struct page) * PAGES_PER_SECTION; mapsize = PAGE_ALIGN(mapsize) >> PAGE_SHIFT; /* remember memmap's page */ for (i = 0; i < mapsize; i++, page++) get_page_bootmem(section_nr, page, SECTION_INFO); usage = ms->usage; page = virt_to_page(usage); mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT; for (i = 0; i < mapsize; i++, page++) get_page_bootmem(section_nr, page, MIX_SECTION_INFO); } #else /* CONFIG_SPARSEMEM_VMEMMAP */ static void register_page_bootmem_info_section(unsigned long start_pfn) { unsigned long mapsize, section_nr, i; struct mem_section *ms; struct page *page, *memmap; struct mem_section_usage *usage; section_nr = pfn_to_section_nr(start_pfn); ms = __nr_to_section(section_nr); memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr); register_page_bootmem_memmap(section_nr, memmap, PAGES_PER_SECTION); usage = ms->usage; page = virt_to_page(usage); mapsize = PAGE_ALIGN(mem_section_usage_size()) >> PAGE_SHIFT; for (i = 0; i < mapsize; i++, page++) get_page_bootmem(section_nr, page, MIX_SECTION_INFO); } #endif /* !CONFIG_SPARSEMEM_VMEMMAP */ void __init register_page_bootmem_info_node(struct pglist_data *pgdat) { unsigned long i, pfn, end_pfn, nr_pages; int node = pgdat->node_id; struct page *page; nr_pages = PAGE_ALIGN(sizeof(struct pglist_data)) >> PAGE_SHIFT; page = virt_to_page(pgdat); for (i = 0; i < nr_pages; i++, page++) get_page_bootmem(node, page, NODE_INFO); pfn = pgdat->node_start_pfn; end_pfn = pgdat_end_pfn(pgdat); /* register section info */ for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { /* * Some platforms can assign the same pfn to multiple nodes - on * node0 as well as nodeN. To avoid registering a pfn against * multiple nodes we check that this pfn does not already * reside in some other nodes. */ if (pfn_valid(pfn) && (early_pfn_to_nid(pfn) == node)) register_page_bootmem_info_section(pfn); } } #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages, const char *reason) { /* * 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, min_align) || !IS_ALIGNED(nr_pages, min_align)) { WARN(1, "Misaligned __%s_pages start: %#lx end: #%lx\n", reason, pfn, pfn + nr_pages - 1); return -EINVAL; } return 0; } static int check_hotplug_memory_addressable(unsigned long pfn, unsigned long nr_pages) { const u64 max_addr = PFN_PHYS(pfn + nr_pages) - 1; if (max_addr >> MAX_PHYSMEM_BITS) { const u64 max_allowed = (1ull << (MAX_PHYSMEM_BITS + 1)) - 1; WARN(1, "Hotplugged memory exceeds maximum addressable address, range=%#llx-%#llx, maximum=%#llx\n", (u64)PFN_PHYS(pfn), max_addr, max_allowed); return -E2BIG; } return 0; } /* * Reasonably generic function for adding memory. It is * expected that archs that support memory hotplug will * call this function after deciding the zone to which to * add the new pages. */ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages, struct mhp_restrictions *restrictions) { int err; unsigned long nr, start_sec, end_sec; struct vmem_altmap *altmap = restrictions->altmap; err = check_hotplug_memory_addressable(pfn, nr_pages); if (err) return err; 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; } err = check_pfn_span(pfn, nr_pages, "add"); if (err) return err; start_sec = pfn_to_section_nr(pfn); end_sec = pfn_to_section_nr(pfn + nr_pages - 1); for (nr = start_sec; nr <= end_sec; nr++) { unsigned long pfns; pfns = min(nr_pages, PAGES_PER_SECTION - (pfn & ~PAGE_SECTION_MASK)); err = sparse_add_section(nid, pfn, pfns, altmap); if (err) break; pfn += pfns; nr_pages -= pfns; 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 && 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 && 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 zone_start_pfn = zone->zone_start_pfn; unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */ unsigned long zone_end_pfn = z; unsigned long pfn; int nid = zone_to_nid(zone); zone_span_writelock(zone); if (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); if (pfn) { zone->zone_start_pfn = pfn; zone->spanned_pages = zone_end_pfn - pfn; } } else if (zone_end_pfn == 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_start_pfn, start_pfn); if (pfn) zone->spanned_pages = pfn - zone_start_pfn + 1; } /* * The section is not biggest or smallest mem_section in the zone, it * only creates a hole in the zone. So in this case, we need not * change the zone. But perhaps, the zone has only hole data. Thus * it check the zone has only hole or not. */ pfn = zone_start_pfn; for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUBSECTION) { if (unlikely(!pfn_to_online_page(pfn))) continue; if (page_zone(pfn_to_page(pfn)) != zone) continue; /* Skip range to be removed */ if (pfn >= start_pfn && pfn < end_pfn) continue; /* If we find valid section, we have nothing to do */ zone_span_writeunlock(zone); return; } /* The zone has no valid section */ zone->zone_start_pfn = 0; zone->spanned_pages = 0; zone_span_writeunlock(zone); } 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 zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; /* 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 = zone_end_pfn; continue; } if (zone_end_pfn > node_end_pfn) node_end_pfn = zone_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; } static void __remove_zone(struct zone *zone, unsigned long start_pfn, unsigned long nr_pages) { struct pglist_data *pgdat = zone->zone_pgdat; unsigned long flags; #ifdef CONFIG_ZONE_DEVICE /* * 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_idx(zone) == ZONE_DEVICE) return; #endif pgdat_resize_lock(zone->zone_pgdat, &flags); shrink_zone_span(zone, start_pfn, start_pfn + nr_pages); update_pgdat_span(pgdat); pgdat_resize_unlock(zone->zone_pgdat, &flags); } static void __remove_section(struct zone *zone, unsigned long pfn, unsigned long nr_pages, unsigned long map_offset, struct vmem_altmap *altmap) { struct mem_section *ms = __nr_to_section(pfn_to_section_nr(pfn)); if (WARN_ON_ONCE(!valid_section(ms))) return; __remove_zone(zone, pfn, nr_pages); sparse_remove_section(ms, pfn, nr_pages, map_offset, altmap); } /** * __remove_pages() - remove sections of pages from a zone * @zone: zone from which pages need to be removed * @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(struct zone *zone, unsigned long pfn, unsigned long nr_pages, struct vmem_altmap *altmap) { unsigned long map_offset = 0; unsigned long nr, start_sec, end_sec; map_offset = vmem_altmap_offset(altmap); clear_zone_contiguous(zone); if (check_pfn_span(pfn, nr_pages, "remove")) return; start_sec = pfn_to_section_nr(pfn); end_sec = pfn_to_section_nr(pfn + nr_pages - 1); for (nr = start_sec; nr <= end_sec; nr++) { unsigned long pfns; cond_resched(); pfns = min(nr_pages, PAGES_PER_SECTION - (pfn & ~PAGE_SECTION_MASK)); __remove_section(zone, pfn, pfns, map_offset, altmap); pfn += pfns; nr_pages -= pfns; map_offset = 0; } set_zone_contiguous(zone); } 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 __online_page_set_limits(struct page *page) { } EXPORT_SYMBOL_GPL(__online_page_set_limits); void generic_online_page(struct page *page, unsigned int order) { kernel_map_pages(page, 1 << order, 1); __free_pages_core(page, order); totalram_pages_add(1UL << order); #ifdef CONFIG_HIGHMEM if (PageHighMem(page)) totalhigh_pages_add(1UL << order); #endif } EXPORT_SYMBOL_GPL(generic_online_page); static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, void *arg) { const unsigned long end_pfn = start_pfn + nr_pages; unsigned long pfn; int order; /* * Online the pages. The callback might decide to keep some pages * PG_reserved (to add them to the buddy later), but we still account * them as being online/belonging to this zone ("present"). */ for (pfn = start_pfn; pfn < end_pfn; pfn += 1ul << order) { order = min(MAX_ORDER - 1, get_order(PFN_PHYS(end_pfn - pfn))); /* __free_pages_core() wants pfns to be aligned to the order */ if (WARN_ON_ONCE(!IS_ALIGNED(pfn, 1ul << order))) order = 0; (*online_page_callback)(pfn_to_page(pfn), order); } /* mark all involved sections as online */ online_mem_sections(start_pfn, end_pfn); *(unsigned long *)arg += nr_pages; return 0; } /* 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; arg->status_change_nid_high = 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; #ifdef CONFIG_HIGHMEM if (zone_idx(zone) <= ZONE_HIGHMEM && !node_state(nid, N_HIGH_MEMORY)) arg->status_change_nid_high = nid; #endif } 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_high >= 0) node_set_state(node, N_HIGH_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; } /* * 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. */ void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn, unsigned long nr_pages, struct vmem_altmap *altmap) { struct pglist_data *pgdat = zone->zone_pgdat; int nid = pgdat->node_id; unsigned long flags; clear_zone_contiguous(zone); /* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */ pgdat_resize_lock(pgdat, &flags); zone_span_writelock(zone); if (zone_is_empty(zone)) init_currently_empty_zone(zone, start_pfn, nr_pages); resize_zone_range(zone, start_pfn, nr_pages); zone_span_writeunlock(zone); resize_pgdat_range(pgdat, start_pfn, nr_pages); pgdat_resize_unlock(pgdat, &flags); /* * 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_zone(nr_pages, nid, zone_idx(zone), start_pfn, MEMMAP_HOTPLUG, altmap); set_zone_contiguous(zone); } /* * 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]; } 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, unsigned 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]; return default_zone_for_pfn(nid, start_pfn, nr_pages); } int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type) { unsigned long flags; unsigned long onlined_pages = 0; struct zone *zone; int need_zonelists_rebuild = 0; int nid; int ret; struct memory_notify arg; struct memory_block *mem; mem_hotplug_begin(); /* * We can't use pfn_to_nid() because nid might be stored in struct page * which is not yet initialized. Instead, we find nid from memory block. */ mem = find_memory_block(__pfn_to_section(pfn)); nid = mem->nid; put_device(&mem->dev); /* associate pfn range with the zone */ zone = zone_for_pfn_range(online_type, nid, pfn, nr_pages); move_pfn_range_to_zone(zone, pfn, nr_pages, NULL); 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; /* * 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); } ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages, online_pages_range); if (ret) { /* not a single memory resource was applicable */ if (need_zonelists_rebuild) zone_pcp_reset(zone); goto failed_addition; } zone->present_pages += onlined_pages; pgdat_resize_lock(zone->zone_pgdat, &flags); zone->zone_pgdat->node_present_pages += onlined_pages; pgdat_resize_unlock(zone->zone_pgdat, &flags); shuffle_zone(zone); node_states_set_node(nid, &arg); if (need_zonelists_rebuild) build_all_zonelists(NULL); else zone_pcp_update(zone); init_per_zone_wmark_min(); kswapd_run(nid); kcompactd_run(nid); vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); memory_notify(MEM_ONLINE, &arg); mem_hotplug_done(); 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); mem_hotplug_done(); return ret; } #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ 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_new_pgdat(int nid, u64 start) { struct pglist_data *pgdat; unsigned long start_pfn = PFN_DOWN(start); pgdat = NODE_DATA(nid); if (!pgdat) { pgdat = arch_alloc_nodedata(nid); if (!pgdat) return NULL; pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat); arch_refresh_nodedata(nid, pgdat); } else { int cpu; /* * Reset the nr_zones, order and classzone_idx before reuse. * Note that kswapd will init kswapd_classzone_idx properly * when it starts in the near future. */ pgdat->nr_zones = 0; pgdat->kswapd_order = 0; pgdat->kswapd_classzone_idx = 0; for_each_online_cpu(cpu) { struct per_cpu_nodestat *p; p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu); memset(p, 0, sizeof(*p)); } } /* we can use NODE_DATA(nid) from here */ pgdat->node_id = nid; pgdat->node_start_pfn = start_pfn; /* init node's zones as empty zones, we don't have any present pages.*/ free_area_init_core_hotplug(nid); /* * 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(). */ reset_node_managed_pages(pgdat); reset_node_present_pages(pgdat); return pgdat; } static void rollback_node_hotadd(int nid) { pg_data_t *pgdat = NODE_DATA(nid); arch_refresh_nodedata(nid, NULL); free_percpu(pgdat->per_cpu_nodestats); arch_free_nodedata(pgdat); } /** * try_online_node - online a node if offlined * @nid: the node ID * @start: start addr of the node * @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, u64 start, bool set_node_online) { pg_data_t *pgdat; int ret = 1; if (node_online(nid)) return 0; pgdat = hotadd_new_pgdat(nid, start); 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, 0, 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) { return device_online(&mem->dev); } /* * 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) { struct mhp_restrictions restrictions = {}; 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; mem_hotplug_begin(); /* * Add new range to memblock so that when hotadd_new_pgdat() is called * to allocate new pgdat, get_pfn_range_for_nid() will be able to find * this new range and calculate total pages correctly. The range will * be removed at hot-remove time. */ memblock_add_node(start, size, nid); ret = __try_online_node(nid, start, false); if (ret < 0) goto error; new_node = ret; /* call arch's memory hotadd */ ret = arch_add_memory(nid, start, size, &restrictions); if (ret < 0) goto error; /* create memory block devices after memory was added */ ret = create_memory_block_devices(start, size); if (ret) { arch_remove_memory(nid, start, size, NULL); 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); } /* link memory sections under this node.*/ ret = link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1)); BUG_ON(ret); /* create new memmap entry */ firmware_map_add_hotplug(start, start + size, "System RAM"); /* device_online() will take the lock when calling online_pages() */ mem_hotplug_done(); /* online pages if requested */ if (memhp_auto_online) walk_memory_blocks(start, size, NULL, online_memory_block); return ret; error: /* rollback pgdat allocation and others */ if (new_node) rollback_node_hotadd(nid); memblock_remove(start, size); mem_hotplug_done(); return ret; } /* requires device_hotplug_lock, see add_memory_resource() */ int __ref __add_memory(int nid, u64 start, u64 size) { struct resource *res; int ret; res = register_memory_resource(start, size); if (IS_ERR(res)) return PTR_ERR(res); ret = add_memory_resource(nid, res); if (ret < 0) release_memory_resource(res); return ret; } int add_memory(int nid, u64 start, u64 size) { int rc; lock_device_hotplug(); rc = __add_memory(nid, start, size); unlock_device_hotplug(); return rc; } EXPORT_SYMBOL_GPL(add_memory); #ifdef CONFIG_MEMORY_HOTREMOVE /* * A free page on the buddy free lists (not the per-cpu lists) has PageBuddy * set and the size of the free page is given by page_order(). Using this, * the function determines if the pageblock contains only free pages. * Due to buddy contraints, a free page at least the size of a pageblock will * be located at the start of the pageblock */ static inline int pageblock_free(struct page *page) { return PageBuddy(page) && page_order(page) >= pageblock_order; } /* Return the pfn of the start of the next active pageblock after a given pfn */ static unsigned long next_active_pageblock(unsigned long pfn) { struct page *page = pfn_to_page(pfn); /* Ensure the starting page is pageblock-aligned */ BUG_ON(pfn & (pageblock_nr_pages - 1)); /* If the entire pageblock is free, move to the end of free page */ if (pageblock_free(page)) { int order; /* be careful. we don't have locks, page_order can be changed.*/ order = page_order(page); if ((order < MAX_ORDER) && (order >= pageblock_order)) return pfn + (1 << order); } return pfn + pageblock_nr_pages; } static bool is_pageblock_removable_nolock(unsigned long pfn) { struct page *page = pfn_to_page(pfn); struct zone *zone; /* * We have to be careful here because we are iterating over memory * sections which are not zone aware so we might end up outside of * the zone but still within the section. * We have to take care about the node as well. If the node is offline * its NODE_DATA will be NULL - see page_zone. */ if (!node_online(page_to_nid(page))) return false; zone = page_zone(page); pfn = page_to_pfn(page); if (!zone_spans_pfn(zone, pfn)) return false; return !has_unmovable_pages(zone, page, 0, MIGRATE_MOVABLE, SKIP_HWPOISON); } /* Checks if this range of memory is likely to be hot-removable. */ bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) { unsigned long end_pfn, pfn; end_pfn = min(start_pfn + nr_pages, zone_end_pfn(page_zone(pfn_to_page(start_pfn)))); /* Check the starting page of each pageblock within the range */ for (pfn = start_pfn; pfn < end_pfn; pfn = next_active_pageblock(pfn)) { if (!is_pageblock_removable_nolock(pfn)) return false; cond_resched(); } /* All pageblocks in the memory block are likely to be hot-removable */ return true; } /* * Confirm all pages in a range [start, end) belong to the same zone. * When true, return its valid [start, end). */ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn, unsigned long *valid_start, unsigned long *valid_end) { unsigned long pfn, sec_end_pfn; unsigned long start, end; struct zone *zone = NULL; struct page *page; int i; for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1); pfn < end_pfn; pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) { /* Make sure the memory section is present first */ if (!present_section_nr(pfn_to_section_nr(pfn))) continue; for (; pfn < sec_end_pfn && pfn < end_pfn; pfn += MAX_ORDER_NR_PAGES) { i = 0; /* This is just a CONFIG_HOLES_IN_ZONE check.*/ while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i)) i++; if (i == MAX_ORDER_NR_PAGES || pfn + i >= end_pfn) continue; /* Check if we got outside of the zone */ if (zone && !zone_spans_pfn(zone, pfn + i)) return 0; page = pfn_to_page(pfn + i); if (zone && page_zone(page) != zone) return 0; if (!zone) start = pfn + i; zone = page_zone(page); end = pfn + MAX_ORDER_NR_PAGES; } } if (zone) { *valid_start = start; *valid_end = min(end, end_pfn); return 1; } else { return 0; } } /* * Scan pfn range [start,end) to find movable/migratable pages (LRU pages, * non-lru movable pages and hugepages). We scan pfn because it's much * easier than scanning over linked list. This function returns the pfn * of the first found movable page if it's found, otherwise 0. */ static unsigned long scan_movable_pages(unsigned long start, unsigned long end) { 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)) return pfn; if (__PageMovable(page)) return pfn; if (!PageHuge(page)) continue; head = compound_head(page); if (page_huge_active(head)) return pfn; skip = compound_nr(head) - (page - head); pfn += skip - 1; } return 0; } static struct page *new_node_page(struct page *page, unsigned long private) { int nid = page_to_nid(page); nodemask_t nmask = node_states[N_MEMORY]; /* * 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(nid, nmask); if (nodes_empty(nmask)) node_set(nid, nmask); return new_page_nodemask(page, nid, &nmask); } static int do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; struct page *page; int ret = 0; LIST_HEAD(source); for (pfn = start_pfn; pfn < end_pfn; pfn++) { if (!pfn_valid(pfn)) continue; page = pfn_to_page(pfn); if (PageHuge(page)) { struct page *head = compound_head(page); pfn = page_to_pfn(head) + compound_nr(head) - 1; isolate_huge_page(head, &source); continue; } else if (PageTransHuge(page)) pfn = page_to_pfn(compound_head(page)) + hpage_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(PageLRU(page))) isolate_lru_page(page); if (page_mapped(page)) try_to_unmap(page, TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS); 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_cache(page)); } else { pr_warn("failed to isolate pfn %lx\n", pfn); dump_page(page, "isolation failed"); } put_page(page); } if (!list_empty(&source)) { /* Allocate a new page from the nearest neighbor node */ ret = migrate_pages(&source, new_node_page, NULL, 0, MIGRATE_SYNC, MR_MEMORY_HOTPLUG); if (ret) { list_for_each_entry(page, &source, lru) { pr_warn("migrating pfn %lx failed ret:%d ", page_to_pfn(page), ret); dump_page(page, "migration failure"); } putback_movable_pages(&source); } } return ret; } /* * remove from free_area[] and mark all as Reserved. */ static int offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages, void *data) { unsigned long *offlined_pages = (unsigned long *)data; *offlined_pages += __offline_isolated_pages(start, start + nr_pages); return 0; } /* * Check all pages in range, recoreded as memory resource, are isolated. */ static int check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages, void *data) { return test_pages_isolated(start_pfn, start_pfn + nr_pages, true); } static int __init cmdline_parse_movable_node(char *p) { #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP movable_node_enabled = true; #else pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n"); #endif 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; arg->status_change_nid_high = 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); #ifdef CONFIG_HIGHMEM /* * node_states[N_HIGH_MEMORY] contains nodes which * have normal memory or high memory. * Here we add the present_pages belonging to ZONE_HIGHMEM. * If the zone is within the range of [0..ZONE_HIGHMEM), and * we determine that the zones in that range become empty, * we need to clear the node for N_HIGH_MEMORY. */ present_pages += pgdat->node_zones[ZONE_HIGHMEM].present_pages; if (zone_idx(zone) <= ZONE_HIGHMEM && nr_pages >= present_pages) arg->status_change_nid_high = zone_to_nid(zone); #endif /* * We have accounted the pages from [0..ZONE_NORMAL), and * in case of CONFIG_HIGHMEM the pages from ZONE_HIGHMEM * as well. * 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_high >= 0) node_clear_state(node, N_HIGH_MEMORY); if (arg->status_change_nid >= 0) node_clear_state(node, N_MEMORY); } static int __ref __offline_pages(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn, nr_pages; unsigned long offlined_pages = 0; int ret, node, nr_isolate_pageblock; unsigned long flags; unsigned long valid_start, valid_end; struct zone *zone; struct memory_notify arg; char *reason; mem_hotplug_begin(); /* This makes hotplug much easier...and readable. we assume this for now. .*/ if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end)) { ret = -EINVAL; reason = "multizone range"; goto failed_removal; } zone = page_zone(pfn_to_page(valid_start)); node = zone_to_nid(zone); nr_pages = end_pfn - start_pfn; /* set above range as isolated */ ret = start_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE, SKIP_HWPOISON | REPORT_FAILURE); if (ret < 0) { reason = "failure to isolate range"; goto failed_removal; } nr_isolate_pageblock = ret; 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 { for (pfn = start_pfn; pfn;) { if (signal_pending(current)) { ret = -EINTR; reason = "signal backoff"; goto failed_removal_isolated; } cond_resched(); lru_add_drain_all(); pfn = scan_movable_pages(pfn, end_pfn); if (pfn) { /* * TODO: fatal migration failures should bail * out */ do_migrate_range(pfn, end_pfn); } } /* * 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; } /* check again */ ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL, check_pages_isolated_cb); } while (ret); /* Ok, all of our target is isolated. We cannot do rollback at this point. */ walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined_pages, offline_isolated_pages_cb); pr_info("Offlined Pages %ld\n", offlined_pages); /* * Onlining will reset pagetype flags and makes migrate type * MOVABLE, so just need to decrease the number of isolated * pageblocks zone counter here. */ spin_lock_irqsave(&zone->lock, flags); zone->nr_isolate_pageblock -= nr_isolate_pageblock; spin_unlock_irqrestore(&zone->lock, flags); /* removal success */ adjust_managed_page_count(pfn_to_page(start_pfn), -offlined_pages); zone->present_pages -= offlined_pages; pgdat_resize_lock(zone->zone_pgdat, &flags); zone->zone_pgdat->node_present_pages -= offlined_pages; pgdat_resize_unlock(zone->zone_pgdat, &flags); init_per_zone_wmark_min(); if (!populated_zone(zone)) { zone_pcp_reset(zone); build_all_zonelists(NULL); } else zone_pcp_update(zone); node_states_clear_node(node, &arg); if (arg.status_change_nid >= 0) { kswapd_stop(node); kcompactd_stop(node); } vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); memory_notify(MEM_OFFLINE, &arg); mem_hotplug_done(); return 0; failed_removal_isolated: undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); memory_notify(MEM_CANCEL_OFFLINE, &arg); 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); /* pushback to free area */ mem_hotplug_done(); return ret; } int offline_pages(unsigned long start_pfn, unsigned long nr_pages) { return __offline_pages(start_pfn, start_pfn + nr_pages); } static int check_memblock_offlined_cb(struct memory_block *mem, void *arg) { int ret = !is_memblock_offlined(mem); if (unlikely(ret)) { 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 check_cpu_on_node(pg_data_t *pgdat) { int cpu; for_each_present_cpu(cpu) { if (cpu_to_node(cpu) == pgdat->node_id) /* * 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) { pg_data_t *pgdat = NODE_DATA(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 (pgdat->node_spanned_pages) 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(pgdat)) 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 void __release_memory_resource(resource_size_t start, resource_size_t size) { int ret; /* * When removing memory in the same granularity as it was added, * this function never fails. It might only fail if resources * have to be adjusted or split. We'll ignore the error, as * removing of memory cannot fail. */ ret = release_mem_region_adjustable(&iomem_resource, start, size); if (ret) { resource_size_t endres = start + size - 1; pr_warn("Unable to release resource <%pa-%pa> (%d)\n", &start, &endres, ret); } } static int __ref try_remove_memory(int nid, u64 start, u64 size) { int rc = 0; BUG_ON(check_hotplug_memory_range(start, size)); mem_hotplug_begin(); /* * 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. */ rc = walk_memory_blocks(start, size, NULL, check_memblock_offlined_cb); if (rc) goto done; /* remove memmap entry */ firmware_map_remove(start, start + size, "System RAM"); /* remove memory block devices before removing memory */ remove_memory_block_devices(start, size); arch_remove_memory(nid, start, size, NULL); memblock_free(start, size); memblock_remove(start, size); __release_memory_resource(start, size); try_offline_node(nid); done: mem_hotplug_done(); return rc; } /** * remove_memory * @nid: the node ID * @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(int nid, u64 start, u64 size) { /* * trigger BUG() if some memory is not offlined prior to calling this * function */ if (try_remove_memory(nid, start, size)) BUG(); } /* * Remove memory if every memory block is offline, otherwise return -EBUSY is * some memory is not offline */ int remove_memory(int nid, u64 start, u64 size) { int rc; lock_device_hotplug(); rc = try_remove_memory(nid, start, size); unlock_device_hotplug(); return rc; } EXPORT_SYMBOL_GPL(remove_memory); #endif /* CONFIG_MEMORY_HOTREMOVE */