/* *  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_SPARSEstatic 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 intdo_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 intoffline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,			void *data){	__offline_isolated_pages(start, start + nr_pages);	return 0;} static voidoffline_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 intcheck_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 longcheck_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. .*/

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