/* * 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/module.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/cpuset.h> #include <linux/delay.h> #include <linux/migrate.h> #include <linux/page-isolation.h> #include <asm/tlbflush.h> /* 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 static int __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; zone_type = zone - pgdat->node_zones; if (!zone->wait_table) { int ret = 0; ret = init_currently_empty_zone(zone, phys_start_pfn, nr_pages, MEMMAP_HOTPLUG); if (ret < 0) return ret; } memmap_init_zone(nr_pages, nid, zone_type, phys_start_pfn, MEMMAP_HOTPLUG); return 0; } static int __add_section(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(__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 __add_pages(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(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); 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 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(page); onlined_pages++; } *(unsigned long *)arg = onlined_pages; return 0; } int online_pages(unsigned long pfn, unsigned long nr_pages) { unsigned long flags; unsigned long onlined_pages = 0; struct zone *zone; int need_zonelists_rebuild = 0; int nid; int ret; struct memory_notify arg; 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); 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_sem. */ zone = page_zone(pfn_to_page(pfn)); pgdat_resize_lock(zone->zone_pgdat, &flags); grow_zone_span(zone, pfn, pfn + nr_pages); grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages); pgdat_resize_unlock(zone->zone_pgdat, &flags); /* * If this zone is not populated, then it is not in zonelist. * This means the page allocator ignores this zone. * So, zonelist must be updated after online. */ if (!populated_zone(zone)) need_zonelists_rebuild = 1; walk_memory_resource(pfn, nr_pages, &onlined_pages, online_pages_range); zone->present_pages += onlined_pages; zone->zone_pgdat->node_present_pages += onlined_pages; setup_per_zone_pages_min(); if (onlined_pages) { kswapd_run(zone_to_nid(zone)); node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); } if (need_zonelists_rebuild) build_all_zonelists(); vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); if (onlined_pages) memory_notify(MEM_ONLINE, &arg); return 0; } #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */ static pg_data_t *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, pgdat, zones_size, start_pfn, zholes_size); return pgdat; } static void rollback_node_hotadd(int nid, pg_data_t *pgdat) { arch_refresh_nodedata(nid, NULL); arch_free_nodedata(pgdat); return; } int add_memory(int nid, u64 start, u64 size) { pg_data_t *pgdat = NULL; int new_pgdat = 0; struct resource *res; int ret; res = register_memory_resource(start, size); if (!res) return -EEXIST; if (!node_online(nid)) { pgdat = hotadd_new_pgdat(nid, start); if (!pgdat) return -ENOMEM; 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); cpuset_track_online_nodes(); 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); } return ret; error: /* rollback pgdat allocation and others */ if (new_pgdat) rollback_node_hotadd(nid, pgdat); if (res) release_memory_resource(res); return ret; } EXPORT_SYMBOL_GPL(add_memory); #ifdef CONFIG_MEMORY_HOTREMOVE /* * 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. */ int 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 improoooooved!! */ return alloc_page(GFP_HIGHUSER_PAGECACHE); } #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 (!page_count(page)) continue; /* * We can skip free pages. And we can only deal with pages on * LRU. */ ret = isolate_lru_page(page, &source); if (!ret) { /* Success */ move_pages--; } else { /* Becasue we don't have big zone->lock. we should check this again here. */ if (page_count(page)) not_managed++; #ifdef CONFIG_DEBUG_VM printk(KERN_INFO "removing from LRU failed" " %lx/%d/%lx\n", pfn, page_count(page), page->flags); #endif } } ret = -EBUSY; if (not_managed) { if (!list_empty(&source)) putback_lru_pages(&source); goto out; } ret = 0; if (list_empty(&source)) goto out; /* this function returns # of failed pages */ ret = migrate_pages(&source, hotremove_migrate_alloc, 0); 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_memory_resource(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_memory_resource(start_pfn, end_pfn - start_pfn, &offlined, check_pages_isolated_cb); if (ret < 0) offlined = (long)ret; return offlined; } int 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; 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) return ret; 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(); flush_scheduled_work(); 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(); flush_scheduled_work(); 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; num_physpages -= offlined_pages; vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); memory_notify(MEM_OFFLINE, &arg); 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); return ret; } #else int remove_memory(u64 start, u64 size) { return -EINVAL; } EXPORT_SYMBOL_GPL(remove_memory); #endif /* CONFIG_MEMORY_HOTREMOVE */