Added an hook for telling the arch when a page has been freed.v_2_4_20_8

1 files changed, 855 insertions, 0 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
new file mode 100644
index 0000000..48cab96
--- /dev/null
+++ b/mm/page_alloc.c
@@ -0,0 +1,855 @@
+/*
+ *  linux/mm/page_alloc.c
+ *
+ *  Manages the free list, the system allocates free pages here.
+ *  Note that kmalloc() lives in slab.c
+ *
+ *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
+ *  Swap reorganised 29.12.95, Stephen Tweedie
+ *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
+ *  Reshaped it to be a zoned allocator, Ingo Molnar, Red Hat, 1999
+ *  Discontiguous memory support, Kanoj Sarcar, SGI, Nov 1999
+ *  Zone balancing, Kanoj Sarcar, SGI, Jan 2000
+ */
+
+#include <linux/config.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/swapctl.h>
+#include <linux/interrupt.h>
+#include <linux/pagemap.h>
+#include <linux/bootmem.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+
+int nr_swap_pages;
+int nr_active_pages;
+int nr_inactive_pages;
+LIST_HEAD(inactive_list);
+LIST_HEAD(active_list);
+pg_data_t *pgdat_list;
+
+/*
+ *
+ * The zone_table array is used to look up the address of the
+ * struct zone corresponding to a given zone number (ZONE_DMA,
+ * ZONE_NORMAL, or ZONE_HIGHMEM).
+ */
+zone_t *zone_table[MAX_NR_ZONES*MAX_NR_NODES];
+EXPORT_SYMBOL(zone_table);
+
+static char *zone_names[MAX_NR_ZONES] = { "DMA", "Normal", "HighMem" };
+static int zone_balance_ratio[MAX_NR_ZONES] __initdata = { 128, 128, 128, };
+static int zone_balance_min[MAX_NR_ZONES] __initdata = { 20 , 20, 20, };
+static int zone_balance_max[MAX_NR_ZONES] __initdata = { 255 , 255, 255, };
+
+/*
+ * Temporary debugging check.
+ */
+#define BAD_RANGE(zone, page)						\
+(									\
+	(((page) - mem_map) >= ((zone)->zone_start_mapnr+(zone)->size))	\
+	|| (((page) - mem_map) < (zone)->zone_start_mapnr)		\
+	|| ((zone) != page_zone(page))					\
+)
+
+/*
+ * Freeing function for a buddy system allocator.
+ * Contrary to prior comments, this is *NOT* hairy, and there
+ * is no reason for anyone not to understand it.
+ *
+ * The concept of a buddy system is to maintain direct-mapped tables
+ * (containing bit values) for memory blocks of various "orders".
+ * The bottom level table contains the map for the smallest allocatable
+ * units of memory (here, pages), and each level above it describes
+ * pairs of units from the levels below, hence, "buddies".
+ * At a high level, all that happens here is marking the table entry
+ * at the bottom level available, and propagating the changes upward
+ * as necessary, plus some accounting needed to play nicely with other
+ * parts of the VM system.
+ * At each level, we keep one bit for each pair of blocks, which
+ * is set to 1 iff only one of the pair is allocated.  So when we
+ * are allocating or freeing one, we can derive the state of the
+ * other.  That is, if we allocate a small block, and both were   
+ * free, the remainder of the region must be split into blocks.   
+ * If a block is freed, and its buddy is also free, then this
+ * triggers coalescing into a block of larger size.            
+ *
+ * -- wli
+ */
+
+static void FASTCALL(__free_pages_ok (struct page *page, unsigned int order));
+static void __free_pages_ok (struct page *page, unsigned int order)
+{
+	unsigned long index, page_idx, mask, flags;
+	free_area_t *area;
+	struct page *base;
+	zone_t *zone;
+
+	arch_free_page(page, order);
+	/*
+	 * Yes, think what happens when other parts of the kernel take 
+	 * a reference to a page in order to pin it for io. -ben
+	 */
+	if (PageLRU(page)) {
+		if (unlikely(in_interrupt()))
+			BUG();
+		lru_cache_del(page);
+	}
+
+	if (page->buffers)
+		BUG();
+	if (page->mapping)
+		BUG();
+	if (!VALID_PAGE(page))
+		BUG();
+	if (PageLocked(page))
+		BUG();
+	if (PageActive(page))
+		BUG();
+	page->flags &= ~((1<<PG_referenced) | (1<<PG_dirty));
+
+	if (current->flags & PF_FREE_PAGES)
+		goto local_freelist;
+ back_local_freelist:
+
+	zone = page_zone(page);
+
+	mask = (~0UL) << order;
+	base = zone->zone_mem_map;
+	page_idx = page - base;
+	if (page_idx & ~mask)
+		BUG();
+	index = page_idx >> (1 + order);
+
+	area = zone->free_area + order;
+
+	spin_lock_irqsave(&zone->lock, flags);
+
+	zone->free_pages -= mask;
+
+	while (mask + (1 << (MAX_ORDER-1))) {
+		struct page *buddy1, *buddy2;
+
+		if (area >= zone->free_area + MAX_ORDER)
+			BUG();
+		if (!__test_and_change_bit(index, area->map))
+			/*
+			 * the buddy page is still allocated.
+			 */
+			break;
+		/*
+		 * Move the buddy up one level.
+		 * This code is taking advantage of the identity:
+		 * 	-mask = 1+~mask
+		 */
+		buddy1 = base + (page_idx ^ -mask);
+		buddy2 = base + page_idx;
+		if (BAD_RANGE(zone,buddy1))
+			BUG();
+		if (BAD_RANGE(zone,buddy2))
+			BUG();
+
+		list_del(&buddy1->list);
+		mask <<= 1;
+		area++;
+		index >>= 1;
+		page_idx &= mask;
+	}
+	list_add(&(base + page_idx)->list, &area->free_list);
+
+	spin_unlock_irqrestore(&zone->lock, flags);
+	return;
+
+ local_freelist:
+	if (current->nr_local_pages)
+		goto back_local_freelist;
+	if (in_interrupt())
+		goto back_local_freelist;		
+
+	list_add(&page->list, &current->local_pages);
+	page->index = order;
+	current->nr_local_pages++;
+}
+
+#define MARK_USED(index, order, area) \
+	__change_bit((index) >> (1+(order)), (area)->map)
+
+static inline struct page * expand (zone_t *zone, struct page *page,
+	 unsigned long index, int low, int high, free_area_t * area)
+{
+	unsigned long size = 1 << high;
+
+	while (high > low) {
+		if (BAD_RANGE(zone,page))
+			BUG();
+		area--;
+		high--;
+		size >>= 1;
+		list_add(&(page)->list, &(area)->free_list);
+		MARK_USED(index, high, area);
+		index += size;
+		page += size;
+	}
+	if (BAD_RANGE(zone,page))
+		BUG();
+	return page;
+}
+
+static FASTCALL(struct page * rmqueue(zone_t *zone, unsigned int order));
+static struct page * rmqueue(zone_t *zone, unsigned int order)
+{
+	free_area_t * area = zone->free_area + order;
+	unsigned int curr_order = order;
+	struct list_head *head, *curr;
+	unsigned long flags;
+	struct page *page;
+
+	spin_lock_irqsave(&zone->lock, flags);
+	do {
+		head = &area->free_list;
+		curr = head->next;
+
+		if (curr != head) {
+			unsigned int index;
+
+			page = list_entry(curr, struct page, list);
+			if (BAD_RANGE(zone,page))
+				BUG();
+			list_del(curr);
+			index = page - zone->zone_mem_map;
+			if (curr_order != MAX_ORDER-1)
+				MARK_USED(index, curr_order, area);
+			zone->free_pages -= 1UL << order;
+
+			page = expand(zone, page, index, order, curr_order, area);
+			spin_unlock_irqrestore(&zone->lock, flags);
+
+			set_page_count(page, 1);
+			if (BAD_RANGE(zone,page))
+				BUG();
+			if (PageLRU(page))
+				BUG();
+			if (PageActive(page))
+				BUG();
+			return page;	
+		}
+		curr_order++;
+		area++;
+	} while (curr_order < MAX_ORDER);
+	spin_unlock_irqrestore(&zone->lock, flags);
+
+	return NULL;
+}
+
+#ifndef CONFIG_DISCONTIGMEM
+struct page *_alloc_pages(unsigned int gfp_mask, unsigned int order)
+{
+	return __alloc_pages(gfp_mask, order,
+		contig_page_data.node_zonelists+(gfp_mask & GFP_ZONEMASK));
+}
+#endif
+
+static struct page * FASTCALL(balance_classzone(zone_t *, unsigned int, unsigned int, int *));
+static struct page * balance_classzone(zone_t * classzone, unsigned int gfp_mask, unsigned int order, int * freed)
+{
+	struct page * page = NULL;
+	int __freed = 0;
+
+	if (!(gfp_mask & __GFP_WAIT))
+		goto out;
+	if (in_interrupt())
+		BUG();
+
+	current->allocation_order = order;
+	current->flags |= PF_MEMALLOC | PF_FREE_PAGES;
+
+	__freed = try_to_free_pages_zone(classzone, gfp_mask);
+
+	current->flags &= ~(PF_MEMALLOC | PF_FREE_PAGES);
+
+	if (current->nr_local_pages) {
+		struct list_head * entry, * local_pages;
+		struct page * tmp;
+		int nr_pages;
+
+		local_pages = &current->local_pages;
+
+		if (likely(__freed)) {
+			/* pick from the last inserted so we're lifo */
+			entry = local_pages->next;
+			do {
+				tmp = list_entry(entry, struct page, list);
+				if (tmp->index == order && memclass(page_zone(tmp), classzone)) {
+					list_del(entry);
+					current->nr_local_pages--;
+					set_page_count(tmp, 1);
+					page = tmp;
+
+					if (page->buffers)
+						BUG();
+					if (page->mapping)
+						BUG();
+					if (!VALID_PAGE(page))
+						BUG();
+					if (PageLocked(page))
+						BUG();
+					if (PageLRU(page))
+						BUG();
+					if (PageActive(page))
+						BUG();
+					if (PageDirty(page))
+						BUG();
+
+					break;
+				}
+			} while ((entry = entry->next) != local_pages);
+		}
+
+		nr_pages = current->nr_local_pages;
+		/* free in reverse order so that the global order will be lifo */
+		while ((entry = local_pages->prev) != local_pages) {
+			list_del(entry);
+			tmp = list_entry(entry, struct page, list);
+			__free_pages_ok(tmp, tmp->index);
+			if (!nr_pages--)
+				BUG();
+		}
+		current->nr_local_pages = 0;
+	}
+ out:
+	*freed = __freed;
+	return page;
+}
+
+/*
+ * This is the 'heart' of the zoned buddy allocator:
+ */
+struct page * __alloc_pages(unsigned int gfp_mask, unsigned int order, zonelist_t *zonelist)
+{
+	unsigned long min;
+	zone_t **zone, * classzone;
+	struct page * page;
+	int freed;
+
+	zone = zonelist->zones;
+	classzone = *zone;
+	if (classzone == NULL)
+		return NULL;
+	min = 1UL << order;
+	for (;;) {
+		zone_t *z = *(zone++);
+		if (!z)
+			break;
+
+		min += z->pages_low;
+		if (z->free_pages > min) {
+			page = rmqueue(z, order);
+			if (page)
+				return page;
+		}
+	}
+
+	classzone->need_balance = 1;
+	mb();
+	if (waitqueue_active(&kswapd_wait))
+		wake_up_interruptible(&kswapd_wait);
+
+	zone = zonelist->zones;
+	min = 1UL << order;
+	for (;;) {
+		unsigned long local_min;
+		zone_t *z = *(zone++);
+		if (!z)
+			break;
+
+		local_min = z->pages_min;
+		if (!(gfp_mask & __GFP_WAIT))
+			local_min >>= 2;
+		min += local_min;
+		if (z->free_pages > min) {
+			page = rmqueue(z, order);
+			if (page)
+				return page;
+		}
+	}
+
+	/* here we're in the low on memory slow path */
+
+rebalance:
+	if (current->flags & (PF_MEMALLOC | PF_MEMDIE)) {
+		zone = zonelist->zones;
+		for (;;) {
+			zone_t *z = *(zone++);
+			if (!z)
+				break;
+
+			page = rmqueue(z, order);
+			if (page)
+				return page;
+		}
+		return NULL;
+	}
+
+	/* Atomic allocations - we can't balance anything */
+	if (!(gfp_mask & __GFP_WAIT))
+		return NULL;
+
+	page = balance_classzone(classzone, gfp_mask, order, &freed);
+	if (page)
+		return page;
+
+	zone = zonelist->zones;
+	min = 1UL << order;
+	for (;;) {
+		zone_t *z = *(zone++);
+		if (!z)
+			break;
+
+		min += z->pages_min;
+		if (z->free_pages > min) {
+			page = rmqueue(z, order);
+			if (page)
+				return page;
+		}
+	}
+
+	/* Don't let big-order allocations loop */
+	if (order > 3)
+		return NULL;
+
+	/* Yield for kswapd, and try again */
+	yield();
+	goto rebalance;
+}
+
+/*
+ * Common helper functions.
+ */
+unsigned long __get_free_pages(unsigned int gfp_mask, unsigned int order)
+{
+	struct page * page;
+
+	page = alloc_pages(gfp_mask, order);
+	if (!page)
+		return 0;
+	return (unsigned long) page_address(page);
+}
+
+unsigned long get_zeroed_page(unsigned int gfp_mask)
+{
+	struct page * page;
+
+	page = alloc_pages(gfp_mask, 0);
+	if (page) {
+		void *address = page_address(page);
+		clear_page(address);
+		return (unsigned long) address;
+	}
+	return 0;
+}
+
+void __free_pages(struct page *page, unsigned int order)
+{
+	if (!PageReserved(page) && put_page_testzero(page))
+		__free_pages_ok(page, order);
+}
+
+void free_pages(unsigned long addr, unsigned int order)
+{
+	if (addr != 0)
+		__free_pages(virt_to_page(addr), order);
+}
+
+/*
+ * Total amount of free (allocatable) RAM:
+ */
+unsigned int nr_free_pages (void)
+{
+	unsigned int sum = 0;
+	zone_t *zone;
+
+	for_each_zone(zone)
+		sum += zone->free_pages;
+
+	return sum;
+}
+
+/*
+ * Amount of free RAM allocatable as buffer memory:
+ */
+unsigned int nr_free_buffer_pages (void)
+{
+	pg_data_t *pgdat;
+	unsigned int sum = 0;
+
+	for_each_pgdat(pgdat) {
+		zonelist_t *zonelist = pgdat->node_zonelists + (GFP_USER & GFP_ZONEMASK);
+		zone_t **zonep = zonelist->zones;
+		zone_t *zone;
+
+		for (zone = *zonep++; zone; zone = *zonep++) {
+			unsigned long size = zone->size;
+			unsigned long high = zone->pages_high;
+			if (size > high)
+				sum += size - high;
+		}
+	}
+
+	return sum;
+}
+
+#if CONFIG_HIGHMEM
+unsigned int nr_free_highpages (void)
+{
+	pg_data_t *pgdat;
+	unsigned int pages = 0;
+
+	for_each_pgdat(pgdat)
+		pages += pgdat->node_zones[ZONE_HIGHMEM].free_pages;
+
+	return pages;
+}
+#endif
+
+#define K(x) ((x) << (PAGE_SHIFT-10))
+
+/*
+ * Show free area list (used inside shift_scroll-lock stuff)
+ * We also calculate the percentage fragmentation. We do this by counting the
+ * memory on each free list with the exception of the first item on the list.
+ */
+void show_free_areas_core(pg_data_t *pgdat)
+{
+ 	unsigned int order;
+	unsigned type;
+	pg_data_t *tmpdat = pgdat;
+
+	printk("Free pages:      %6dkB (%6dkB HighMem)\n",
+		K(nr_free_pages()),
+		K(nr_free_highpages()));
+
+	while (tmpdat) {
+		zone_t *zone;
+		for (zone = tmpdat->node_zones;
+			       	zone < tmpdat->node_zones + MAX_NR_ZONES; zone++)
+			printk("Zone:%s freepages:%6lukB min:%6lukB low:%6lukB " 
+				       "high:%6lukB\n", 
+					zone->name,
+					K(zone->free_pages),
+					K(zone->pages_min),
+					K(zone->pages_low),
+					K(zone->pages_high));
+			
+		tmpdat = tmpdat->node_next;
+	}
+
+	printk("( Active: %d, inactive: %d, free: %d )\n",
+	       nr_active_pages,
+	       nr_inactive_pages,
+	       nr_free_pages());
+
+	for (type = 0; type < MAX_NR_ZONES; type++) {
+		struct list_head *head, *curr;
+		zone_t *zone = pgdat->node_zones + type;
+ 		unsigned long nr, total, flags;
+
+		total = 0;
+		if (zone->size) {
+			spin_lock_irqsave(&zone->lock, flags);
+		 	for (order = 0; order < MAX_ORDER; order++) {
+				head = &(zone->free_area + order)->free_list;
+				curr = head;
+				nr = 0;
+				for (;;) {
+					if ((curr = curr->next) == head)
+						break;
+					nr++;
+				}
+				total += nr * (1 << order);
+				printk("%lu*%lukB ", nr, K(1UL) << order);
+			}
+			spin_unlock_irqrestore(&zone->lock, flags);
+		}
+		printk("= %lukB)\n", K(total));
+	}
+
+#ifdef SWAP_CACHE_INFO
+	show_swap_cache_info();
+#endif	
+}
+
+void show_free_areas(void)
+{
+	show_free_areas_core(pgdat_list);
+}
+
+/*
+ * Builds allocation fallback zone lists.
+ */
+static inline void build_zonelists(pg_data_t *pgdat)
+{
+	int i, j, k;
+
+	for (i = 0; i <= GFP_ZONEMASK; i++) {
+		zonelist_t *zonelist;
+		zone_t *zone;
+
+		zonelist = pgdat->node_zonelists + i;
+		memset(zonelist, 0, sizeof(*zonelist));
+
+		j = 0;
+		k = ZONE_NORMAL;
+		if (i & __GFP_HIGHMEM)
+			k = ZONE_HIGHMEM;
+		if (i & __GFP_DMA)
+			k = ZONE_DMA;
+
+		switch (k) {
+			default:
+				BUG();
+			/*
+			 * fallthrough:
+			 */
+			case ZONE_HIGHMEM:
+				zone = pgdat->node_zones + ZONE_HIGHMEM;
+				if (zone->size) {
+#ifndef CONFIG_HIGHMEM
+					BUG();
+#endif
+					zonelist->zones[j++] = zone;
+				}
+			case ZONE_NORMAL:
+				zone = pgdat->node_zones + ZONE_NORMAL;
+				if (zone->size)
+					zonelist->zones[j++] = zone;
+			case ZONE_DMA:
+				zone = pgdat->node_zones + ZONE_DMA;
+				if (zone->size)
+					zonelist->zones[j++] = zone;
+		}
+		zonelist->zones[j++] = NULL;
+	} 
+}
+
+/*
+ * Helper functions to size the waitqueue hash table.
+ * Essentially these want to choose hash table sizes sufficiently
+ * large so that collisions trying to wait on pages are rare.
+ * But in fact, the number of active page waitqueues on typical
+ * systems is ridiculously low, less than 200. So this is even
+ * conservative, even though it seems large.
+ *
+ * The constant PAGES_PER_WAITQUEUE specifies the ratio of pages to
+ * waitqueues, i.e. the size of the waitq table given the number of pages.
+ */
+#define PAGES_PER_WAITQUEUE	256
+
+static inline unsigned long wait_table_size(unsigned long pages)
+{
+	unsigned long size = 1;
+
+	pages /= PAGES_PER_WAITQUEUE;
+
+	while (size < pages)
+		size <<= 1;
+
+	/*
+	 * Once we have dozens or even hundreds of threads sleeping
+	 * on IO we've got bigger problems than wait queue collision.
+	 * Limit the size of the wait table to a reasonable size.
+	 */
+	size = min(size, 4096UL);
+
+	return size;
+}
+
+/*
+ * This is an integer logarithm so that shifts can be used later
+ * to extract the more random high bits from the multiplicative
+ * hash function before the remainder is taken.
+ */
+static inline unsigned long wait_table_bits(unsigned long size)
+{
+	return ffz(~size);
+}
+
+#define LONG_ALIGN(x) (((x)+(sizeof(long))-1)&~((sizeof(long))-1))
+
+/*
+ * Set up the zone data structures:
+ *   - mark all pages reserved
+ *   - mark all memory queues empty
+ *   - clear the memory bitmaps
+ */
+void __init free_area_init_core(int nid, pg_data_t *pgdat, struct page **gmap,
+	unsigned long *zones_size, unsigned long zone_start_paddr, 
+	unsigned long *zholes_size, struct page *lmem_map)
+{
+	unsigned long i, j;
+	unsigned long map_size;
+	unsigned long totalpages, offset, realtotalpages;
+	const unsigned long zone_required_alignment = 1UL << (MAX_ORDER-1);
+
+	if (zone_start_paddr & ~PAGE_MASK)
+		BUG();
+
+	totalpages = 0;
+	for (i = 0; i < MAX_NR_ZONES; i++) {
+		unsigned long size = zones_size[i];
+		totalpages += size;
+	}
+	realtotalpages = totalpages;
+	if (zholes_size)
+		for (i = 0; i < MAX_NR_ZONES; i++)
+			realtotalpages -= zholes_size[i];
+			
+	printk("On node %d totalpages: %lu\n", nid, realtotalpages);
+
+	/*
+	 * Some architectures (with lots of mem and discontinous memory
+	 * maps) have to search for a good mem_map area:
+	 * For discontigmem, the conceptual mem map array starts from 
+	 * PAGE_OFFSET, we need to align the actual array onto a mem map 
+	 * boundary, so that MAP_NR works.
+	 */
+	map_size = (totalpages + 1)*sizeof(struct page);
+	if (lmem_map == (struct page *)0) {
+		lmem_map = (struct page *) alloc_bootmem_node(pgdat, map_size);
+		lmem_map = (struct page *)(PAGE_OFFSET + 
+			MAP_ALIGN((unsigned long)lmem_map - PAGE_OFFSET));
+	}
+	*gmap = pgdat->node_mem_map = lmem_map;
+	pgdat->node_size = totalpages;
+	pgdat->node_start_paddr = zone_start_paddr;
+	pgdat->node_start_mapnr = (lmem_map - mem_map);
+	pgdat->nr_zones = 0;
+
+	offset = lmem_map - mem_map;	
+	for (j = 0; j < MAX_NR_ZONES; j++) {
+		zone_t *zone = pgdat->node_zones + j;
+		unsigned long mask;
+		unsigned long size, realsize;
+
+		zone_table[nid * MAX_NR_ZONES + j] = zone;
+		realsize = size = zones_size[j];
+		if (zholes_size)
+			realsize -= zholes_size[j];
+
+		printk("zone(%lu): %lu pages.\n", j, size);
+		zone->size = size;
+		zone->name = zone_names[j];
+		zone->lock = SPIN_LOCK_UNLOCKED;
+		zone->zone_pgdat = pgdat;
+		zone->free_pages = 0;
+		zone->need_balance = 0;
+		if (!size)
+			continue;
+
+		/*
+		 * The per-page waitqueue mechanism uses hashed waitqueues
+		 * per zone.
+		 */
+		zone->wait_table_size = wait_table_size(size);
+		zone->wait_table_shift =
+			BITS_PER_LONG - wait_table_bits(zone->wait_table_size);
+		zone->wait_table = (wait_queue_head_t *)
+			alloc_bootmem_node(pgdat, zone->wait_table_size
+						* sizeof(wait_queue_head_t));
+
+		for(i = 0; i < zone->wait_table_size; ++i)
+			init_waitqueue_head(zone->wait_table + i);
+
+		pgdat->nr_zones = j+1;
+
+		mask = (realsize / zone_balance_ratio[j]);
+		if (mask < zone_balance_min[j])
+			mask = zone_balance_min[j];
+		else if (mask > zone_balance_max[j])
+			mask = zone_balance_max[j];
+		zone->pages_min = mask;
+		zone->pages_low = mask*2;
+		zone->pages_high = mask*3;
+
+		zone->zone_mem_map = mem_map + offset;
+		zone->zone_start_mapnr = offset;
+		zone->zone_start_paddr = zone_start_paddr;
+
+		if ((zone_start_paddr >> PAGE_SHIFT) & (zone_required_alignment-1))
+			printk("BUG: wrong zone alignment, it will crash\n");
+
+		/*
+		 * Initially all pages are reserved - free ones are freed
+		 * up by free_all_bootmem() once the early boot process is
+		 * done. Non-atomic initialization, single-pass.
+		 */
+		for (i = 0; i < size; i++) {
+			struct page *page = mem_map + offset + i;
+			set_page_zone(page, nid * MAX_NR_ZONES + j);
+			set_page_count(page, 0);
+			SetPageReserved(page);
+			INIT_LIST_HEAD(&page->list);
+			if (j != ZONE_HIGHMEM)
+				set_page_address(page, __va(zone_start_paddr));
+			zone_start_paddr += PAGE_SIZE;
+		}
+
+		offset += size;
+		for (i = 0; ; i++) {
+			unsigned long bitmap_size;
+
+			INIT_LIST_HEAD(&zone->free_area[i].free_list);
+			if (i == MAX_ORDER-1) {
+				zone->free_area[i].map = NULL;
+				break;
+			}
+
+			/*
+			 * Page buddy system uses "index >> (i+1)",
+			 * where "index" is at most "size-1".
+			 *
+			 * The extra "+3" is to round down to byte
+			 * size (8 bits per byte assumption). Thus
+			 * we get "(size-1) >> (i+4)" as the last byte
+			 * we can access.
+			 *
+			 * The "+1" is because we want to round the
+			 * byte allocation up rather than down. So
+			 * we should have had a "+7" before we shifted
+			 * down by three. Also, we have to add one as
+			 * we actually _use_ the last bit (it's [0,n]
+			 * inclusive, not [0,n[).
+			 *
+			 * So we actually had +7+1 before we shift
+			 * down by 3. But (n+8) >> 3 == (n >> 3) + 1
+			 * (modulo overflows, which we do not have).
+			 *
+			 * Finally, we LONG_ALIGN because all bitmap
+			 * operations are on longs.
+			 */
+			bitmap_size = (size-1) >> (i+4);
+			bitmap_size = LONG_ALIGN(bitmap_size+1);
+			zone->free_area[i].map = 
+			  (unsigned long *) alloc_bootmem_node(pgdat, bitmap_size);
+		}
+	}
+	build_zonelists(pgdat);
+}
+
+void __init free_area_init(unsigned long *zones_size)
+{
+	free_area_init_core(0, &contig_page_data, &mem_map, zones_size, 0, 0, 0);
+}
+
+static int __init setup_mem_frac(char *str)
+{
+	int j = 0;
+
+	while (get_option(&str, &zone_balance_ratio[j++]) == 2);
+	printk("setup_mem_frac: ");
+	for (j = 0; j < MAX_NR_ZONES; j++) printk("%d  ", zone_balance_ratio[j]);
+	printk("\n");
+	return 1;
+}
+
+__setup("memfrac=", setup_mem_frac);