/* * linux/mm/memory_hotplug.c * * Copyright (C) */ #include <linux/stddef.h> #include <linux/mm.h> #include <linux/swap.h> #include <linux/interrupt.h> #include <linux/pagemap.h> #include <linux/bootmem.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/memory_hotplug.h> #include <linux/highmem.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 <asm/tlbflush.h> #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 %llx - %llx cannot be added\n", (unsigned long long)res->start, (unsigned long long)res->end); 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 #ifndef CONFIG_SPARSEMEM_VMEMMAP static 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; 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); __free_pages_bootmem(page, 0); } } 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); /* 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); } 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 = pfn + pgdat->node_spanned_pages; /* register_section info */ for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) register_page_bootmem_info_section(pfn); } #endif /* !CONFIG_SPARSEMEM_VMEMMAP */ 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 (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 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 (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; zone_type = zone - pgdat->node_zones; if (!zone->wait_table) { int ret; ret = init_currently_empty_zone(zone, phys_start_pfn, nr_pages, MEMMAP_HOTPLUG); 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)); } #ifdef CONFIG_SPARSEMEM_VMEMMAP static int __remove_section(struct zone *zone, struct mem_section *ms) { /* * XXX: Freeing memmap with vmemmap is not implement yet. * This should be removed later. */ return -EBUSY; } #else static int __remove_section(struct zone *zone, struct mem_section *ms) { unsigned long flags; struct pglist_data *pgdat = zone->zone_pgdat; int ret = -EINVAL; if (!valid_section(ms)) return ret; ret = unregister_memory_section(ms); if (ret) return ret; pgdat_resize_lock(pgdat, &flags); sparse_remove_one_section(zone, ms); pgdat_resize_unlock(pgdat, &flags); return 0; } #endif /* * 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); /** * __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, ret = 0; int sections_to_remove; /* * We can only remove entire sections */ BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK); BUG_ON(nr_pages % PAGES_PER_SECTION); 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; release_mem_region(pfn << PAGE_SHIFT, PAGES_PER_SECTION << PAGE_SHIFT); ret = __remove_section(zone, __pfn_to_section(pfn)); if (ret) break; } return ret; } EXPORT_SYMBOL_GPL(__remove_pages); 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; } int __ref online_pages(unsigned long pfn, unsigned long nr_pages) { unsigned long onlined_pages = 0; struct zone *zone; int need_zonelists_rebuild = 0; int nid; int ret; struct memory_notify arg; lock_memory_hotplug(); arg.start_pfn = pfn; arg.nr_pages = nr_pages; arg.status_change_nid = -1; nid = page_to_nid(pfn_to_page(pfn)); if (node_present_pages(nid) == 0) arg.status_change_nid = nid; 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; } /* * 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 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; ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages, online_pages_range); if (ret) { mutex_unlock(&zonelists_mutex); printk(KERN_DEBUG "online_pages %lx at %lx failed\n", nr_pages, pfn); memory_notify(MEM_CANCEL_ONLINE, &arg); unlock_memory_hotplug(); return ret; } zone->present_pages += onlined_pages; zone->zone_pgdat->node_present_pages += onlined_pages; if (need_zonelists_rebuild) build_all_zonelists(zone); else zone_pcp_update(zone); mutex_unlock(&zonelists_mutex); init_per_zone_wmark_min(); if (onlined_pages) { kswapd_run(zone_to_nid(zone)); node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); } 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 = 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(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; int new_pgdat = 0; struct resource *res; int ret; lock_memory_hotplug(); res = register_memory_resource(start, size); ret = -EEXIST; if (!res) goto out; if (!node_online(nid)) { pgdat = hotadd_new_pgdat(nid, start); ret = -ENOMEM; if (!pgdat) goto out; new_pgdat = 1; } /* 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_pgdat) { 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); if (res) 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; } static struct page * hotremove_migrate_alloc(struct page *page, unsigned long private, int **x) { /* This should be improooooved!! */ return alloc_page(GFP_HIGHUSER_MOVABLE); } #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; } /* this function returns # of failed pages */ ret = migrate_pages(&source, hotremove_migrate_alloc, 0, true, true); 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); 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; } 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; /* set above range as isolated */ ret = start_isolate_page_range(start_pfn, end_pfn); if (ret) goto out; arg.start_pfn = start_pfn; arg.nr_pages = nr_pages; arg.status_change_nid = -1; if (nr_pages >= node_present_pages(node)) arg.status_change_nid = node; 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 asyncronous... */ lru_add_drain_all(); yield(); /* drain pcp pages , this is synchrouns. */ 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 islaoted. 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); /* removal success */ zone->present_pages -= offlined_pages; zone->zone_pgdat->node_present_pages -= offlined_pages; totalram_pages -= offlined_pages; init_per_zone_wmark_min(); if (!node_present_pages(node)) { node_clear_state(node, N_HIGH_MEMORY); 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 %lx to %lx failed\n", start_pfn, end_pfn); memory_notify(MEM_CANCEL_OFFLINE, &arg); /* pushback to free area */ undo_isolate_page_range(start_pfn, end_pfn); out: unlock_memory_hotplug(); return ret; } int remove_memory(u64 start, u64 size) { unsigned long start_pfn, end_pfn; start_pfn = PFN_DOWN(start); end_pfn = start_pfn + PFN_DOWN(size); return offline_pages(start_pfn, end_pfn, 120 * HZ); } #else int remove_memory(u64 start, u64 size) { return -EINVAL; } #endif /* CONFIG_MEMORY_HOTREMOVE */ EXPORT_SYMBOL_GPL(remove_memory);