/* * 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 "internal.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 void generic_online_page(struct page *page); static online_page_callback_t online_page_callback = generic_online_page; DEFINE_MUTEX(mem_hotplug_mutex); void lock_memory_hotplug(void) { mutex_lock(&mem_hotplug_mutex); /* for exclusive hibernation if CONFIG_HIBERNATION=y */ lock_system_sleep(); } void unlock_memory_hotplug(void) { unlock_system_sleep(); mutex_unlock(&mem_hotplug_mutex); } /* add this memory to iomem resource */ static struct resource *register_memory_resource(u64 start, u64 size) { struct resource *res; res = kzalloc(sizeof(struct resource), GFP_KERNEL); BUG_ON(!res); res->name = "System RAM"; res->start = start; res->end = start + size - 1; res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; if (request_resource(&iomem_resource, res) < 0) { printk("System RAM resource %pR cannot be added\n", res); kfree(res); res = NULL; } return res; } static void release_memory_resource(struct resource *res) { if (!res) return; release_resource(res); kfree(res); return; } #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE void get_page_bootmem(unsigned long info, struct page *page, unsigned long type) { page->lru.next = (struct list_head *) type; SetPagePrivate(page); set_page_private(page, info); atomic_inc(&page->_count); } /* reference to __meminit __free_pages_bootmem is valid * so use __ref to tell modpost not to generate a warning */ void __ref put_page_bootmem(struct page *page) { unsigned long type; static DEFINE_MUTEX(ppb_lock); type = (unsigned long) page->lru.next; BUG_ON(type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE); if (atomic_dec_return(&page->_count) == 1) { ClearPagePrivate(page); set_page_private(page, 0); INIT_LIST_HEAD(&page->lru); /* * Please refer to comment for __free_pages_bootmem() * for why we serialize here. */ mutex_lock(&ppb_lock); __free_pages_bootmem(page, 0); mutex_unlock(&ppb_lock); totalram_pages++; } } #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE #ifndef CONFIG_SPARSEMEM_VMEMMAP static void register_page_bootmem_info_section(unsigned long start_pfn) { unsigned long *usemap, mapsize, section_nr, i; struct mem_section *ms; struct page *page, *memmap; 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); usemap = __nr_to_section(section_nr)->pageblock_flags; page = virt_to_page(usemap); mapsize = PAGE_ALIGN(usemap_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 *usemap, mapsize, section_nr, i; struct mem_section *ms; struct page *page, *memmap; if (!pfn_valid(start_pfn)) return; 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); usemap = __nr_to_section(section_nr)->pageblock_flags; page = virt_to_page(usemap); mapsize = PAGE_ALIGN(usemap_size()) >> PAGE_SHIFT; for (i = 0; i < mapsize; i++, page++) get_page_bootmem(section_nr, page, MIX_SECTION_INFO); } #endif /* !CONFIG_SPARSEMEM_VMEMMAP */ void 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; struct zone *zone; 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); zone = &pgdat->node_zones[0]; for (; zone < pgdat->node_zones + MAX_NR_ZONES - 1; zone++) { if (zone->wait_table) { nr_pages = zone->wait_table_hash_nr_entries * sizeof(wait_queue_head_t); nr_pages = PAGE_ALIGN(nr_pages) >> PAGE_SHIFT; page = virt_to_page(zone->wait_table); 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 node. */ if (pfn_valid(pfn) && (pfn_to_nid(pfn) == node)) register_page_bootmem_info_section(pfn); } } #endif /* CONFIG_HAVE_BOOTMEM_INFO_NODE */ static void grow_zone_span(struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) { unsigned long old_zone_end_pfn; zone_span_writelock(zone); old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; if (!zone->spanned_pages || start_pfn < zone->zone_start_pfn) zone->zone_start_pfn = start_pfn; zone->spanned_pages = max(old_zone_end_pfn, end_pfn) - zone->zone_start_pfn; zone_span_writeunlock(zone); } static void resize_zone(struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) { zone_span_writelock(zone); if (end_pfn - start_pfn) { zone->zone_start_pfn = start_pfn; zone->spanned_pages = end_pfn - start_pfn; } else { /* * make it consist as free_area_init_core(), * if spanned_pages = 0, then keep start_pfn = 0 */ zone->zone_start_pfn = 0; zone->spanned_pages = 0; } zone_span_writeunlock(zone); } static void fix_zone_id(struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) { enum zone_type zid = zone_idx(zone); int nid = zone->zone_pgdat->node_id; unsigned long pfn; for (pfn = start_pfn; pfn < end_pfn; pfn++) set_page_links(pfn_to_page(pfn), zid, nid, pfn); } /* Can fail with -ENOMEM from allocating a wait table with vmalloc() or * alloc_bootmem_node_nopanic() */ static int __ref ensure_zone_is_initialized(struct zone *zone, unsigned long start_pfn, unsigned long num_pages) { if (!zone_is_initialized(zone)) return init_currently_empty_zone(zone, start_pfn, num_pages, MEMMAP_HOTPLUG); return 0; } static int __meminit move_pfn_range_left(struct zone *z1, struct zone *z2, unsigned long start_pfn, unsigned long end_pfn) { int ret; unsigned long flags; unsigned long z1_start_pfn; ret = ensure_zone_is_initialized(z1, start_pfn, end_pfn - start_pfn); if (ret) return ret; pgdat_resize_lock(z1->zone_pgdat, &flags); /* can't move pfns which are higher than @z2 */ if (end_pfn > zone_end_pfn(z2)) goto out_fail; /* the move out part mast at the left most of @z2 */ if (start_pfn > z2->zone_start_pfn) goto out_fail; /* must included/overlap */ if (end_pfn <= z2->zone_start_pfn) goto out_fail; /* use start_pfn for z1's start_pfn if z1 is empty */ if (z1->spanned_pages) z1_start_pfn = z1->zone_start_pfn; else z1_start_pfn = start_pfn; resize_zone(z1, z1_start_pfn, end_pfn); resize_zone(z2, end_pfn, zone_end_pfn(z2)); pgdat_resize_unlock(z1->zone_pgdat, &flags); fix_zone_id(z1, start_pfn, end_pfn); return 0; out_fail: pgdat_resize_unlock(z1->zone_pgdat, &flags); return -1; } static int __meminit move_pfn_range_right(struct zone *z1, struct zone *z2, unsigned long start_pfn, unsigned long end_pfn) { int ret; unsigned long flags; unsigned long z2_end_pfn; ret = ensure_zone_is_initialized(z2, start_pfn, end_pfn - start_pfn); if (ret) return ret; pgdat_resize_lock(z1->zone_pgdat, &flags); /* can't move pfns which are lower than @z1 */ if (z1->zone_start_pfn > start_pfn) goto out_fail; /* the move out part mast at the right most of @z1 */ if (zone_end_pfn(z1) > end_pfn) goto out_fail; /* must included/overlap */ if (start_pfn >= zone_end_pfn(z1)) goto out_fail; /* use end_pfn for z2's end_pfn if z2 is empty */ if (z2->spanned_pages) z2_end_pfn = zone_end_pfn(z2); else z2_end_pfn = end_pfn; resize_zone(z1, z1->zone_start_pfn, start_pfn); resize_zone(z2, start_pfn, z2_end_pfn); pgdat_resize_unlock(z1->zone_pgdat, &flags); fix_zone_id(z2, start_pfn, end_pfn); return 0; out_fail: pgdat_resize_unlock(z1->zone_pgdat, &flags); return -1; } static void grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn, unsigned long end_pfn) { unsigned long old_pgdat_end_pfn = pgdat->node_start_pfn + pgdat->node_spanned_pages; if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn) pgdat->node_start_pfn = start_pfn; pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) - pgdat->node_start_pfn; } static int __meminit __add_zone(struct zone *zone, unsigned long phys_start_pfn) { struct pglist_data *pgdat = zone->zone_pgdat; int nr_pages = PAGES_PER_SECTION; int nid = pgdat->node_id; int zone_type; unsigned long flags; int ret; zone_type = zone - pgdat->node_zones; ret = ensure_zone_is_initialized(zone, phys_start_pfn, nr_pages); if (ret) return ret; pgdat_resize_lock(zone->zone_pgdat, &flags); grow_zone_span(zone, phys_start_pfn, phys_start_pfn + nr_pages); grow_pgdat_span(zone->zone_pgdat, phys_start_pfn, phys_start_pfn + nr_pages); pgdat_resize_unlock(zone->zone_pgdat, &flags); memmap_init_zone(nr_pages, nid, zone_type, phys_start_pfn, MEMMAP_HOTPLUG); return 0; } static int __meminit __add_section(int nid, struct zone *zone, unsigned long phys_start_pfn) { int nr_pages = PAGES_PER_SECTION; int ret; if (pfn_valid(phys_start_pfn)) return -EEXIST; ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages); if (ret < 0) return ret; ret = __add_zone(zone, phys_start_pfn); if (ret < 0) return ret; return register_new_memory(nid, __pfn_to_section(phys_start_pfn)); } /* * 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, struct zone *zone, unsigned long phys_start_pfn, unsigned long nr_pages) { unsigned long i; int err = 0; int start_sec, end_sec; /* during initialize mem_map, align hot-added range to section */ start_sec = pfn_to_section_nr(phys_start_pfn); end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1); for (i = start_sec; i <= end_sec; i++) { err = __add_section(nid, zone, i << PFN_SECTION_SHIFT); /* * EEXIST is finally dealt with by ioresource collision * check. see add_memory() => register_memory_resource() * Warning will be printed if there is collision. */ if (err && (err != -EEXIST)) break; err = 0; } return err; } EXPORT_SYMBOL_GPL(__add_pages); #ifdef CONFIG_MEMORY_HOTREMOVE /* find the smallest valid pfn in the range [start_pfn, end_pfn) */ static int find_smallest_section_pfn(int nid, struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) { struct mem_section *ms; for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SECTION) { ms = __pfn_to_section(start_pfn); if (unlikely(!valid_section(ms))) 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 int find_biggest_section_pfn(int nid, struct zone *zone, unsigned long start_pfn, unsigned long end_pfn) { struct mem_section *ms; unsigned long pfn; /* pfn is the end pfn of a memory section. */ pfn = end_pfn - 1; for (; pfn >= start_pfn; pfn -= PAGES_PER_SECTION) { ms = __pfn_to_section(pfn); if (unlikely(!valid_section(ms))) 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 zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages; unsigned long pfn; struct mem_section *ms; 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_SECTION) { ms = __pfn_to_section(pfn); if (unlikely(!valid_section(ms))) continue; if (page_zone(pfn_to_page(pfn)) != zone) continue; /* If the section is current section, it continues the loop */ if (start_pfn == 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 shrink_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn, unsigned long end_pfn) { unsigned long pgdat_start_pfn = pgdat->node_start_pfn; unsigned long pgdat_end_pfn = pgdat->node_start_pfn + pgdat->node_spanned_pages; unsigned long pfn; struct mem_section *ms; int nid = pgdat->node_id; if (pgdat_start_pfn == start_pfn) { /* * If the section is smallest section in the pgdat, it need * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages. * In this case, we find second smallest valid mem_section * for shrinking zone. */ pfn = find_smallest_section_pfn(nid, NULL, end_pfn, pgdat_end_pfn); if (pfn) { pgdat->node_start_pfn = pfn; pgdat->node_spanned_pages = pgdat_end_pfn - pfn; } } else if (pgdat_end_pfn == end_pfn) { /* * If the section is biggest section in the pgdat, it need * shrink pgdat->node_spanned_pages. * In this case, we find second biggest valid mem_section for * shrinking zone. */ pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn, start_pfn); if (pfn) pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1; } /* * If the section is not biggest or smallest mem_section in the pgdat, * it only creates a hole in the pgdat. So in this case, we need not * change the pgdat. * But perhaps, the pgdat has only hole data. Thus it check the pgdat * has only hole or not. */ pfn = pgdat_start_pfn; for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) { ms = __pfn_to_section(pfn); if (unlikely(!valid_section(ms))) continue; if (pfn_to_nid(pfn) != nid) continue; /* If the section is current section, it continues the loop */ if (start_pfn == pfn) continue; /* If we find valid section, we have nothing to do */ return; } /* The pgdat has no valid section */ pgdat->node_start_pfn = 0; pgdat->node_spanned_pages = 0; } static void __remove_zone(struct zone *zone, unsigned long start_pfn) { struct pglist_data *pgdat = zone->zone_pgdat; int nr_pages = PAGES_PER_SECTION; int zone_type; unsigned long flags; zone_type = zone - pgdat->node_zones; pgdat_resize_lock(zone->zone_pgdat, &flags); shrink_zone_span(zone, start_pfn, start_pfn + nr_pages); shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages); pgdat_resize_unlock(zone->zone_pgdat, &flags); } static int __remove_section(struct zone *zone, struct mem_section *ms) { unsigned long start_pfn; int scn_nr; int ret = -EINVAL; if (!valid_section(ms)) return ret; ret = unregister_memory_section(ms); if (ret) return ret; scn_nr = __section_nr(ms); start_pfn = section_nr_to_pfn(scn_nr); __remove_zone(zone, start_pfn); sparse_remove_one_section(zone, ms); return 0; } /** * __remove_pages() - remove sections of pages from a zone * @zone: zone from which pages need to be removed * @phys_start_pfn: starting pageframe (must be aligned to start of a section) * @nr_pages: number of pages to remove (must be multiple of section size) * * 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(). */ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn, unsigned long nr_pages) { unsigned long i; int sections_to_remove; resource_size_t start, size; int ret = 0; /* * We can only remove entire sections */ BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); BUG_ON(nr_pages % PAGES_PER_SECTION); start = phys_start_pfn << PAGE_SHIFT; size = nr_pages * PAGE_SIZE; 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); } sections_to_remove = nr_pages / PAGES_PER_SECTION; for (i = 0; i < sections_to_remove; i++) { unsigned long pfn = phys_start_pfn + i*PAGES_PER_SECTION; ret = __remove_section(zone, __pfn_to_section(pfn)); if (ret) break; } return ret; } EXPORT_SYMBOL_GPL(__remove_pages); #endif /* CONFIG_MEMORY_HOTREMOVE */ int set_online_page_callback(online_page_callback_t callback) { int rc = -EINVAL; lock_memory_hotplug(); if (online_page_callback == generic_online_page) { online_page_callback = callback; rc = 0; } unlock_memory_hotplug(); return rc; } EXPORT_SYMBOL_GPL(set_online_page_callback); int restore_online_page_callback(online_page_callback_t callback) { int rc = -EINVAL; lock_memory_hotplug(); if (online_page_callback == callback) { online_page_callback = generic_online_page; rc = 0; } unlock_memory_hotplug(); return rc; } EXPORT_SYMBOL_GPL(restore_online_page_callback); void __online_page_set_limits(struct page *page) { unsigned long pfn = page_to_pfn(page); if (pfn >= num_physpages) num_physpages = pfn + 1; } EXPORT_SYMBOL_GPL(__online_page_set_limits); void __online_page_increment_counters(struct page *page) { totalram_pages++; #ifdef CONFIG_HIGHMEM if (PageHighMem(page)) totalhigh_pages++; #endif } EXPORT_SYMBOL_GPL(__online_page_increment_counters); void __online_page_free(struct page *page) { ClearPageReserved(page); init_page_count(page); __free_page(page); } EXPORT_SYMBOL_GPL(__online_page_free); static void generic_online_page(struct page *page) { __online_page_set_limits(page); __online_page_increment_counters(page); __online_page_free(page); } static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, void *arg) { unsigned long i; unsigned long onlined_pages = *(unsigned long *)arg; struct page *page; if (PageReserved(pfn_to_page(start_pfn))) for (i = 0; i < nr_pages; i++) { page = pfn_to_page(start_pfn + i); (*online_page_callback)(page); onlined_pages++; } *(unsigned long *)arg = onlined_pages; return 0; } #ifdef CONFIG_MOVABLE_NODE /* * When CONFIG_MOVABLE_NODE, we permit onlining of a node which doesn't have * normal memory. */ static bool can_online_high_movable(struct zone *zone) { return true; } #else /* CONFIG_MOVABLE_NODE */ /* ensure every online node has NORMAL memory */ static bool can_online_high_movable(struct zone *zone) { return node_state(zone_to_nid(zone), N_NORMAL_MEMORY); } #endif /* CONFIG_MOVABLE_NODE */ /* 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); enum zone_type zone_last = ZONE_NORMAL; /* * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY] * contains nodes which have zones of 0...ZONE_NORMAL, * set zone_last to ZONE_NORMAL. * * If we don't have HIGHMEM nor movable node, * node_states[N_NORMAL_MEMORY] contains nodes which have zones of * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE. */ if (N_MEMORY == N_NORMAL_MEMORY) zone_last = ZONE_MOVABLE; /* * if the memory to be online is in a zone of 0...zone_last, and * the zones of 0...zone_last don't have memory before online, we will * need to set the node to node_states[N_NORMAL_MEMORY] after * the memory is online. */ if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY)) arg->status_change_nid_normal = nid; else arg->status_change_nid_normal = -1; #ifdef CONFIG_HIGHMEM /* * If we have movable node, node_states[N_HIGH_MEMORY] * contains nodes which have zones of 0...ZONE_HIGHMEM, * set zone_last to ZONE_HIGHMEM. * * If we don't have movable node, node_states[N_NORMAL_MEMORY] * contains nodes which have zones of 0...ZONE_MOVABLE, * set zone_last to ZONE_MOVABLE. */ zone_last = ZONE_HIGHMEM; if (N_MEMORY == N_HIGH_MEMORY) zone_last = ZONE_MOVABLE; if (zone_idx(zone) <= zone_last && !node_state(nid, N_HIGH_MEMORY)) arg->status_change_nid_high = nid; else arg->status_change_nid_high = -1; #else arg->status_change_nid_high = arg->status_change_nid_normal; #endif /* * if the node don't have memory befor online, we will need to * set the node to node_states[N_MEMORY] after the memory * is online. */ if (!node_state(nid, N_MEMORY)) arg->status_change_nid = nid; else arg->status_change_nid = -1; } 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); node_set_state(node, N_MEMORY); } int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type) { unsigned long onlined_pages = 0; struct zone *zone; int need_zonelists_rebuild = 0; int nid; int ret; struct memory_notify arg; lock_memory_hotplug(); /* * This doesn't need a lock to do pfn_to_page(). * The section can't be removed here because of the * memory_block->state_mutex. */ zone = page_zone(pfn_to_page(pfn)); if ((zone_idx(zone) > ZONE_NORMAL || online_type == ONLINE_MOVABLE) && !can_online_high_movable(zone)) { unlock_memory_hotplug(); return -1; } if (online_type == ONLINE_KERNEL && zone_idx(zone) == ZONE_MOVABLE) { if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages)) { unlock_memory_hotplug(); return -1; } } if (online_type == ONLINE_MOVABLE && zone_idx(zone) == ZONE_MOVABLE - 1) { if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages)) { unlock_memory_hotplug(); return -1; } } /* Previous code may changed the zone of the pfn range */ zone = page_zone(pfn_to_page(pfn)); arg.start_pfn = pfn; arg.nr_pages = nr_pages; node_states_check_changes_online(nr_pages, zone, &arg); nid = page_to_nid(pfn_to_page(pfn)); ret = memory_notify(MEM_GOING_ONLINE, &arg); ret = notifier_to_errno(ret); if (ret) { memory_notify(MEM_CANCEL_ONLINE, &arg); unlock_memory_hotplug(); return ret; } /* * 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. */ mutex_lock(&zonelists_mutex); if (!populated_zone(zone)) { need_zonelists_rebuild = 1; build_all_zonelists(NULL, zone); } ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages, online_pages_range); if (ret) { if (need_zonelists_rebuild) zone_pcp_reset(zone); mutex_unlock(&zonelists_mutex); printk(KERN_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); unlock_memory_hotplug(); return ret; } zone->managed_pages += onlined_pages; zone->present_pages += onlined_pages; zone->zone_pgdat->node_present_pages += onlined_pages; if (onlined_pages) { node_states_set_node(zone_to_nid(zone), &arg); if (need_zonelists_rebuild) build_all_zonelists(NULL, NULL); else zone_pcp_update(zone); } mutex_unlock(&zonelists_mutex); init_per_zone_wmark_min(); if (onlined_pages) kswapd_run(zone_to_nid(zone)); vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); if (onlined_pages) memory_notify(MEM_ONLINE, &arg); unlock_memory_hotplug(); return 0; } #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ /* 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 zones_size[MAX_NR_ZONES] = {0}; unsigned long zholes_size[MAX_NR_ZONES] = {0}; unsigned long start_pfn = start >> PAGE_SHIFT; pgdat = NODE_DATA(nid); if (!pgdat) { pgdat = arch_alloc_nodedata(nid); if (!pgdat) return NULL; arch_refresh_nodedata(nid, pgdat); } /* we can use NODE_DATA(nid) from here */ /* init node's zones as empty zones, we don't have any present pages.*/ free_area_init_node(nid, zones_size, start_pfn, zholes_size); /* * The node we allocated has no zone fallback lists. For avoiding * to access not-initialized zonelist, build here. */ mutex_lock(&zonelists_mutex); build_all_zonelists(pgdat, NULL); mutex_unlock(&zonelists_mutex); return pgdat; } static void rollback_node_hotadd(int nid, pg_data_t *pgdat) { arch_refresh_nodedata(nid, NULL); arch_free_nodedata(pgdat); return; } /* * called by cpu_up() to online a node without onlined memory. */ int mem_online_node(int nid) { pg_data_t *pgdat; int ret; lock_memory_hotplug(); pgdat = hotadd_new_pgdat(nid, 0); if (!pgdat) { ret = -ENOMEM; goto out; } node_set_online(nid); ret = register_one_node(nid); BUG_ON(ret); out: unlock_memory_hotplug(); return ret; } /* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */ int __ref add_memory(int nid, u64 start, u64 size) { pg_data_t *pgdat = NULL; bool new_pgdat; bool new_node; struct resource *res; int ret; lock_memory_hotplug(); res = register_memory_resource(start, size); ret = -EEXIST; if (!res) goto out; { /* Stupid hack to suppress address-never-null warning */ void *p = NODE_DATA(nid); new_pgdat = !p; } new_node = !node_online(nid); if (new_node) { pgdat = hotadd_new_pgdat(nid, start); ret = -ENOMEM; if (!pgdat) goto error; } /* call arch's memory hotadd */ ret = arch_add_memory(nid, start, size); if (ret < 0) goto error; /* we online node here. we can't roll back from here. */ node_set_online(nid); if (new_node) { ret = register_one_node(nid); /* * If sysfs file of new node can't create, cpu on the node * can't be hot-added. There is no rollback way now. * So, check by BUG_ON() to catch it reluctantly.. */ BUG_ON(ret); } /* create new memmap entry */ firmware_map_add_hotplug(start, start + size, "System RAM"); goto out; error: /* rollback pgdat allocation and others */ if (new_pgdat) rollback_node_hotadd(nid, pgdat); release_memory_resource(res); out: unlock_memory_hotplug(); return ret; } 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 start of the next active pageblock after a given page */ static struct page *next_active_pageblock(struct page *page) { /* Ensure the starting page is pageblock-aligned */ BUG_ON(page_to_pfn(page) & (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 page + (1 << order); } return page + pageblock_nr_pages; } /* Checks if this range of memory is likely to be hot-removable. */ int is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages) { struct page *page = pfn_to_page(start_pfn); struct page *end_page = page + nr_pages; /* Check the starting page of each pageblock within the range */ for (; page < end_page; page = next_active_pageblock(page)) { if (!is_pageblock_removable_nolock(page)) return 0; cond_resched(); } /* All pageblocks in the memory block are likely to be hot-removable */ return 1; } /* * Confirm all pages in a range [start, end) is belongs to the same zone. */ static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; struct zone *zone = NULL; struct page *page; int i; for (pfn = start_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) continue; page = pfn_to_page(pfn + i); if (zone && page_zone(page) != zone) return 0; zone = page_zone(page); } return 1; } /* * Scanning pfn is much easier than scanning lru list. * Scan pfn from start to end and Find LRU page. */ static unsigned long scan_lru_pages(unsigned long start, unsigned long end) { unsigned long pfn; struct page *page; for (pfn = start; pfn < end; pfn++) { if (pfn_valid(pfn)) { page = pfn_to_page(pfn); if (PageLRU(page)) return pfn; } } return 0; } #define NR_OFFLINE_AT_ONCE_PAGES (256) static int do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; struct page *page; int move_pages = NR_OFFLINE_AT_ONCE_PAGES; int not_managed = 0; int ret = 0; LIST_HEAD(source); for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) { if (!pfn_valid(pfn)) continue; page = pfn_to_page(pfn); if (!get_page_unless_zero(page)) continue; /* * We can skip free pages. And we can only deal with pages on * LRU. */ ret = isolate_lru_page(page); if (!ret) { /* Success */ put_page(page); list_add_tail(&page->lru, &source); move_pages--; inc_zone_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); } else { #ifdef CONFIG_DEBUG_VM printk(KERN_ALERT "removing pfn %lx from LRU failed\n", pfn); dump_page(page); #endif put_page(page); /* Because we don't have big zone->lock. we should check this again here. */ if (page_count(page)) { not_managed++; ret = -EBUSY; break; } } } if (!list_empty(&source)) { if (not_managed) { putback_lru_pages(&source); goto out; } /* * alloc_migrate_target should be improooooved!! * migrate_pages returns # of failed pages. */ ret = migrate_pages(&source, alloc_migrate_target, 0, MIGRATE_SYNC, MR_MEMORY_HOTPLUG); if (ret) putback_lru_pages(&source); } out: 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) { __offline_isolated_pages(start, start + nr_pages); return 0; } static void offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) { walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL, offline_isolated_pages_cb); } /* * 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) { int ret; long offlined = *(long *)data; ret = test_pages_isolated(start_pfn, start_pfn + nr_pages, true); offlined = nr_pages; if (!ret) *(long *)data += offlined; return ret; } static long check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) { long offlined = 0; int ret; ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined, check_pages_isolated_cb); if (ret < 0) offlined = (long)ret; return offlined; } #ifdef CONFIG_MOVABLE_NODE /* * When CONFIG_MOVABLE_NODE, we permit offlining of a node which doesn't have * normal memory. */ static bool can_offline_normal(struct zone *zone, unsigned long nr_pages) { return true; } #else /* CONFIG_MOVABLE_NODE */ /* ensure the node has NORMAL memory if it is still online */ static bool can_offline_normal(struct zone *zone, unsigned long nr_pages) { struct pglist_data *pgdat = zone->zone_pgdat; unsigned long present_pages = 0; enum zone_type zt; for (zt = 0; zt <= ZONE_NORMAL; zt++) present_pages += pgdat->node_zones[zt].present_pages; if (present_pages > nr_pages) return true; present_pages = 0; for (; zt <= ZONE_MOVABLE; zt++) present_pages += pgdat->node_zones[zt].present_pages; /* * we can't offline the last normal memory until all * higher memory is offlined. */ return present_pages == 0; } #endif /* CONFIG_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, zone_last = ZONE_NORMAL; /* * If we have HIGHMEM or movable node, node_states[N_NORMAL_MEMORY] * contains nodes which have zones of 0...ZONE_NORMAL, * set zone_last to ZONE_NORMAL. * * If we don't have HIGHMEM nor movable node, * node_states[N_NORMAL_MEMORY] contains nodes which have zones of * 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE. */ if (N_MEMORY == N_NORMAL_MEMORY) zone_last = ZONE_MOVABLE; /* * check whether node_states[N_NORMAL_MEMORY] will be changed. * If the memory to be offline is in a zone of 0...zone_last, * and it is the last present memory, 0...zone_last will * become empty after offline , thus we can determind we will * need to clear the node from node_states[N_NORMAL_MEMORY]. */ for (zt = 0; zt <= zone_last; zt++) present_pages += pgdat->node_zones[zt].present_pages; if (zone_idx(zone) <= zone_last && nr_pages >= present_pages) arg->status_change_nid_normal = zone_to_nid(zone); else arg->status_change_nid_normal = -1; #ifdef CONFIG_HIGHMEM /* * If we have movable node, node_states[N_HIGH_MEMORY] * contains nodes which have zones of 0...ZONE_HIGHMEM, * set zone_last to ZONE_HIGHMEM. * * If we don't have movable node, node_states[N_NORMAL_MEMORY] * contains nodes which have zones of 0...ZONE_MOVABLE, * set zone_last to ZONE_MOVABLE. */ zone_last = ZONE_HIGHMEM; if (N_MEMORY == N_HIGH_MEMORY) zone_last = ZONE_MOVABLE; for (; zt <= zone_last; zt++) present_pages += pgdat->node_zones[zt].present_pages; if (zone_idx(zone) <= zone_last && nr_pages >= present_pages) arg->status_change_nid_high = zone_to_nid(zone); else arg->status_change_nid_high = -1; #else arg->status_change_nid_high = arg->status_change_nid_normal; #endif /* * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE */ zone_last = ZONE_MOVABLE; /* * check whether node_states[N_HIGH_MEMORY] will be changed * If we try to offline the last present @nr_pages from the node, * we can determind we will need to clear the node from * node_states[N_HIGH_MEMORY]. */ for (; zt <= zone_last; zt++) present_pages += pgdat->node_zones[zt].present_pages; if (nr_pages >= present_pages) arg->status_change_nid = zone_to_nid(zone); else arg->status_change_nid = -1; } 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 ((N_MEMORY != N_NORMAL_MEMORY) && (arg->status_change_nid_high >= 0)) node_clear_state(node, N_HIGH_MEMORY); if ((N_MEMORY != N_HIGH_MEMORY) && (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 timeout) { unsigned long pfn, nr_pages, expire; long offlined_pages; int ret, drain, retry_max, node; struct zone *zone; struct memory_notify arg; BUG_ON(start_pfn >= end_pfn); /* at least, alignment against pageblock is necessary */ if (!IS_ALIGNED(start_pfn, pageblock_nr_pages)) return -EINVAL; if (!IS_ALIGNED(end_pfn, pageblock_nr_pages)) return -EINVAL; /* This makes hotplug much easier...and readable. we assume this for now. .*/ if (!test_pages_in_a_zone(start_pfn, end_pfn)) return -EINVAL; lock_memory_hotplug(); zone = page_zone(pfn_to_page(start_pfn)); node = zone_to_nid(zone); nr_pages = end_pfn - start_pfn; ret = -EINVAL; if (zone_idx(zone) <= ZONE_NORMAL && !can_offline_normal(zone, nr_pages)) goto out; /* set above range as isolated */ ret = start_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE, true); if (ret) goto out; 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) goto failed_removal; pfn = start_pfn; expire = jiffies + timeout; drain = 0; retry_max = 5; repeat: /* start memory hot removal */ ret = -EAGAIN; if (time_after(jiffies, expire)) goto failed_removal; ret = -EINTR; if (signal_pending(current)) goto failed_removal; ret = 0; if (drain) { lru_add_drain_all(); cond_resched(); drain_all_pages(); } pfn = scan_lru_pages(start_pfn, end_pfn); if (pfn) { /* We have page on LRU */ ret = do_migrate_range(pfn, end_pfn); if (!ret) { drain = 1; goto repeat; } else { if (ret < 0) if (--retry_max == 0) goto failed_removal; yield(); drain = 1; goto repeat; } } /* drain all zone's lru pagevec, this is asynchronous... */ lru_add_drain_all(); yield(); /* drain pcp pages, this is synchronous. */ drain_all_pages(); /* check again */ offlined_pages = check_pages_isolated(start_pfn, end_pfn); if (offlined_pages < 0) { ret = -EBUSY; goto failed_removal; } printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages); /* Ok, all of our target is isolated. We cannot do rollback at this point. */ offline_isolated_pages(start_pfn, end_pfn); /* reset pagetype flags and makes migrate type to be MOVABLE */ undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); /* removal success */ zone->managed_pages -= offlined_pages; zone->present_pages -= offlined_pages; zone->zone_pgdat->node_present_pages -= offlined_pages; totalram_pages -= offlined_pages; init_per_zone_wmark_min(); if (!populated_zone(zone)) { zone_pcp_reset(zone); mutex_lock(&zonelists_mutex); build_all_zonelists(NULL, NULL); mutex_unlock(&zonelists_mutex); } else zone_pcp_update(zone); node_states_clear_node(node, &arg); if (arg.status_change_nid >= 0) kswapd_stop(node); vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); memory_notify(MEM_OFFLINE, &arg); unlock_memory_hotplug(); return 0; failed_removal: printk(KERN_INFO "memory offlining [mem %#010llx-%#010llx] failed\n", (unsigned long long) start_pfn << PAGE_SHIFT, ((unsigned long long) end_pfn << PAGE_SHIFT) - 1); memory_notify(MEM_CANCEL_OFFLINE, &arg); /* pushback to free area */ undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE); out: unlock_memory_hotplug(); return ret; } int offline_pages(unsigned long start_pfn, unsigned long nr_pages) { return __offline_pages(start_pfn, start_pfn + nr_pages, 120 * HZ); } /** * walk_memory_range - walks through all mem sections in [start_pfn, end_pfn) * @start_pfn: start pfn of the memory range * @end_pfn: end pfn of the memory range * @arg: argument passed to func * @func: callback for each memory section walked * * This function walks through all present mem sections in range * [start_pfn, end_pfn) and call func on each mem section. * * Returns the return value of func. */ static int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn, void *arg, int (*func)(struct memory_block *, void *)) { struct memory_block *mem = NULL; struct mem_section *section; unsigned long pfn, section_nr; int ret; for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { section_nr = pfn_to_section_nr(pfn); if (!present_section_nr(section_nr)) continue; section = __nr_to_section(section_nr); /* same memblock? */ if (mem) if ((section_nr >= mem->start_section_nr) && (section_nr <= mem->end_section_nr)) continue; mem = find_memory_block_hinted(section, mem); if (!mem) continue; ret = func(mem, arg); if (ret) { kobject_put(&mem->dev.kobj); return ret; } } if (mem) kobject_put(&mem->dev.kobj); return 0; } /** * offline_memory_block_cb - callback function for offlining memory block * @mem: the memory block to be offlined * @arg: buffer to hold error msg * * Always return 0, and put the error msg in arg if any. */ static int offline_memory_block_cb(struct memory_block *mem, void *arg) { int *ret = arg; int error = offline_memory_block(mem); if (error != 0 && *ret == 0) *ret = error; return 0; } static int is_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 = PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1))-1; pr_warn("removing memory fails, because memory " "[%pa-%pa] is onlined\n", &beginpa, &endpa); } return ret; } static int check_cpu_on_node(void *data) { struct pglist_data *pgdat = data; 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 void unmap_cpu_on_node(void *data) { #ifdef CONFIG_ACPI_NUMA struct pglist_data *pgdat = data; int cpu; for_each_possible_cpu(cpu) if (cpu_to_node(cpu) == pgdat->node_id) numa_clear_node(cpu); #endif } static int check_and_unmap_cpu_on_node(void *data) { int ret = check_cpu_on_node(data); if (ret) return ret; /* * the node will be offlined when we come here, so we can clear * the cpu_to_node() now. */ unmap_cpu_on_node(data); return 0; } /* offline the node if all memory sections of this node are removed */ void try_offline_node(int nid) { pg_data_t *pgdat = NODE_DATA(nid); unsigned long start_pfn = pgdat->node_start_pfn; unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages; unsigned long pfn; struct page *pgdat_page = virt_to_page(pgdat); int i; for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { unsigned long section_nr = pfn_to_section_nr(pfn); if (!present_section_nr(section_nr)) continue; if (pfn_to_nid(pfn) != nid) continue; /* * some memory sections of this node are not removed, and we * can't offline node now. */ return; } if (stop_machine(check_and_unmap_cpu_on_node, pgdat, NULL)) return; /* * all memory/cpu of this node are removed, we can offline this * node now. */ node_set_offline(nid); unregister_one_node(nid); if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page)) /* node data is allocated from boot memory */ return; /* free waittable in each zone */ for (i = 0; i < MAX_NR_ZONES; i++) { struct zone *zone = pgdat->node_zones + i; /* * wait_table may be allocated from boot memory, * here only free if it's allocated by vmalloc. */ if (is_vmalloc_addr(zone->wait_table)) vfree(zone->wait_table); } /* * Since there is no way to guarentee the address of pgdat/zone is not * on stack of any kernel threads or used by other kernel objects * without reference counting or other symchronizing method, do not * reset node_data and free pgdat here. Just reset it to 0 and reuse * the memory when the node is online again. */ memset(pgdat, 0, sizeof(*pgdat)); } EXPORT_SYMBOL(try_offline_node); int __ref remove_memory(int nid, u64 start, u64 size) { unsigned long start_pfn, end_pfn; int ret = 0; int retry = 1; start_pfn = PFN_DOWN(start); end_pfn = PFN_UP(start + size - 1); /* * When CONFIG_MEMCG is on, one memory block may be used by other * blocks to store page cgroup when onlining pages. But we don't know * in what order pages are onlined. So we iterate twice to offline * memory: * 1st iterate: offline every non primary memory block. * 2nd iterate: offline primary (i.e. first added) memory block. */ repeat: walk_memory_range(start_pfn, end_pfn, &ret, offline_memory_block_cb); if (ret) { if (!retry) return ret; retry = 0; ret = 0; goto repeat; } lock_memory_hotplug(); /* * we have offlined all memory blocks like this: * 1. lock memory hotplug * 2. offline a memory block * 3. unlock memory hotplug * * repeat step1-3 to offline the memory block. All memory blocks * must be offlined before removing memory. But we don't hold the * lock in the whole operation. So we should check whether all * memory blocks are offlined. */ ret = walk_memory_range(start_pfn, end_pfn, NULL, is_memblock_offlined_cb); if (ret) { unlock_memory_hotplug(); return ret; } /* remove memmap entry */ firmware_map_remove(start, start + size, "System RAM"); arch_remove_memory(start, size); try_offline_node(nid); unlock_memory_hotplug(); return 0; } #else int offline_pages(unsigned long start_pfn, unsigned long nr_pages) { return -EINVAL; } int remove_memory(int nid, u64 start, u64 size) { return -EINVAL; } #endif /* CONFIG_MEMORY_HOTREMOVE */ EXPORT_SYMBOL_GPL(remove_memory);