page_alloc.c 90.9 KB
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/*
 *  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
 *  Per cpu hot/cold page lists, bulk allocation, Martin J. Bligh, Sept 2002
 *          (lots of bits borrowed from Ingo Molnar & Andrew Morton)
 */

#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>
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#include <linux/kernel.h>
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#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/topology.h>
#include <linux/sysctl.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
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#include <linux/memory_hotplug.h>
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#include <linux/nodemask.h>
#include <linux/vmalloc.h>
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#include <linux/mempolicy.h>
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#include <linux/stop_machine.h>
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#include <linux/sort.h>
#include <linux/pfn.h>
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#include <linux/backing-dev.h>
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#include <linux/fault-inject.h>
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#include <asm/tlbflush.h>
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#include <asm/div64.h>
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#include "internal.h"

/*
 * MCD - HACK: Find somewhere to initialize this EARLY, or make this
 * initializer cleaner
 */
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nodemask_t node_online_map __read_mostly = { { [0] = 1UL } };
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EXPORT_SYMBOL(node_online_map);
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nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
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EXPORT_SYMBOL(node_possible_map);
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unsigned long totalram_pages __read_mostly;
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unsigned long totalreserve_pages __read_mostly;
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long nr_swap_pages;
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int percpu_pagelist_fraction;
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static void __free_pages_ok(struct page *page, unsigned int order);
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/*
 * results with 256, 32 in the lowmem_reserve sysctl:
 *	1G machine -> (16M dma, 800M-16M normal, 1G-800M high)
 *	1G machine -> (16M dma, 784M normal, 224M high)
 *	NORMAL allocation will leave 784M/256 of ram reserved in the ZONE_DMA
 *	HIGHMEM allocation will leave 224M/32 of ram reserved in ZONE_NORMAL
 *	HIGHMEM allocation will (224M+784M)/256 of ram reserved in ZONE_DMA
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 *
 * TBD: should special case ZONE_DMA32 machines here - in those we normally
 * don't need any ZONE_NORMAL reservation
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 */
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int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = {
	 256,
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#ifdef CONFIG_ZONE_DMA32
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	 256,
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#endif
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#ifdef CONFIG_HIGHMEM
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	 32
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#endif
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};
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EXPORT_SYMBOL(totalram_pages);

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static char * const zone_names[MAX_NR_ZONES] = {
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	 "DMA",
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#ifdef CONFIG_ZONE_DMA32
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	 "DMA32",
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#endif
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	 "Normal",
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#ifdef CONFIG_HIGHMEM
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	 "HighMem"
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#endif
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};

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int min_free_kbytes = 1024;

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unsigned long __meminitdata nr_kernel_pages;
unsigned long __meminitdata nr_all_pages;
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static unsigned long __initdata dma_reserve;
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#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
  /*
   * MAX_ACTIVE_REGIONS determines the maxmimum number of distinct
   * ranges of memory (RAM) that may be registered with add_active_range().
   * Ranges passed to add_active_range() will be merged if possible
   * so the number of times add_active_range() can be called is
   * related to the number of nodes and the number of holes
   */
  #ifdef CONFIG_MAX_ACTIVE_REGIONS
    /* Allow an architecture to set MAX_ACTIVE_REGIONS to save memory */
    #define MAX_ACTIVE_REGIONS CONFIG_MAX_ACTIVE_REGIONS
  #else
    #if MAX_NUMNODES >= 32
      /* If there can be many nodes, allow up to 50 holes per node */
      #define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
    #else
      /* By default, allow up to 256 distinct regions */
      #define MAX_ACTIVE_REGIONS 256
    #endif
  #endif

  struct node_active_region __initdata early_node_map[MAX_ACTIVE_REGIONS];
  int __initdata nr_nodemap_entries;
  unsigned long __initdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
  unsigned long __initdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
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#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
  unsigned long __initdata node_boundary_start_pfn[MAX_NUMNODES];
  unsigned long __initdata node_boundary_end_pfn[MAX_NUMNODES];
#endif /* CONFIG_MEMORY_HOTPLUG_RESERVE */
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#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */

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#ifdef CONFIG_DEBUG_VM
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static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
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{
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	int ret = 0;
	unsigned seq;
	unsigned long pfn = page_to_pfn(page);
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	do {
		seq = zone_span_seqbegin(zone);
		if (pfn >= zone->zone_start_pfn + zone->spanned_pages)
			ret = 1;
		else if (pfn < zone->zone_start_pfn)
			ret = 1;
	} while (zone_span_seqretry(zone, seq));

	return ret;
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}

static int page_is_consistent(struct zone *zone, struct page *page)
{
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#ifdef CONFIG_HOLES_IN_ZONE
	if (!pfn_valid(page_to_pfn(page)))
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		return 0;
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#endif
	if (zone != page_zone(page))
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		return 0;

	return 1;
}
/*
 * Temporary debugging check for pages not lying within a given zone.
 */
static int bad_range(struct zone *zone, struct page *page)
{
	if (page_outside_zone_boundaries(zone, page))
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		return 1;
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	if (!page_is_consistent(zone, page))
		return 1;

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	return 0;
}
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#else
static inline int bad_range(struct zone *zone, struct page *page)
{
	return 0;
}
#endif

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static void bad_page(struct page *page)
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{
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	printk(KERN_EMERG "Bad page state in process '%s'\n"
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		KERN_EMERG "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
		KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
		KERN_EMERG "Backtrace:\n",
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		current->comm, page, (int)(2*sizeof(unsigned long)),
		(unsigned long)page->flags, page->mapping,
		page_mapcount(page), page_count(page));
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	dump_stack();
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	page->flags &= ~(1 << PG_lru	|
			1 << PG_private |
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			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_dirty	|
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			1 << PG_reclaim |
			1 << PG_slab    |
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			1 << PG_swapcache |
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			1 << PG_writeback |
			1 << PG_buddy );
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	set_page_count(page, 0);
	reset_page_mapcount(page);
	page->mapping = NULL;
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	add_taint(TAINT_BAD_PAGE);
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}

/*
 * Higher-order pages are called "compound pages".  They are structured thusly:
 *
 * The first PAGE_SIZE page is called the "head page".
 *
 * The remaining PAGE_SIZE pages are called "tail pages".
 *
 * All pages have PG_compound set.  All pages have their ->private pointing at
 * the head page (even the head page has this).
 *
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 * The first tail page's ->lru.next holds the address of the compound page's
 * put_page() function.  Its ->lru.prev holds the order of allocation.
 * This usage means that zero-order pages may not be compound.
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 */
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static void free_compound_page(struct page *page)
{
	__free_pages_ok(page, (unsigned long)page[1].lru.prev);
}

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static void prep_compound_page(struct page *page, unsigned long order)
{
	int i;
	int nr_pages = 1 << order;

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	set_compound_page_dtor(page, free_compound_page);
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	page[1].lru.prev = (void *)order;
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	for (i = 0; i < nr_pages; i++) {
		struct page *p = page + i;

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		__SetPageCompound(p);
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		set_page_private(p, (unsigned long)page);
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	}
}

static void destroy_compound_page(struct page *page, unsigned long order)
{
	int i;
	int nr_pages = 1 << order;

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	if (unlikely((unsigned long)page[1].lru.prev != order))
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		bad_page(page);
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	for (i = 0; i < nr_pages; i++) {
		struct page *p = page + i;

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		if (unlikely(!PageCompound(p) |
				(page_private(p) != (unsigned long)page)))
			bad_page(page);
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		__ClearPageCompound(p);
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	}
}

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static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
{
	int i;

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	VM_BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM);
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	/*
	 * clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
	 * and __GFP_HIGHMEM from hard or soft interrupt context.
	 */
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	VM_BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
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	for (i = 0; i < (1 << order); i++)
		clear_highpage(page + i);
}

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/*
 * function for dealing with page's order in buddy system.
 * zone->lock is already acquired when we use these.
 * So, we don't need atomic page->flags operations here.
 */
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static inline unsigned long page_order(struct page *page)
{
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	return page_private(page);
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}

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static inline void set_page_order(struct page *page, int order)
{
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	set_page_private(page, order);
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	__SetPageBuddy(page);
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}

static inline void rmv_page_order(struct page *page)
{
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	__ClearPageBuddy(page);
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	set_page_private(page, 0);
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}

/*
 * Locate the struct page for both the matching buddy in our
 * pair (buddy1) and the combined O(n+1) page they form (page).
 *
 * 1) Any buddy B1 will have an order O twin B2 which satisfies
 * the following equation:
 *     B2 = B1 ^ (1 << O)
 * For example, if the starting buddy (buddy2) is #8 its order
 * 1 buddy is #10:
 *     B2 = 8 ^ (1 << 1) = 8 ^ 2 = 10
 *
 * 2) Any buddy B will have an order O+1 parent P which
 * satisfies the following equation:
 *     P = B & ~(1 << O)
 *
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 * Assumption: *_mem_map is contiguous at least up to MAX_ORDER
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 */
static inline struct page *
__page_find_buddy(struct page *page, unsigned long page_idx, unsigned int order)
{
	unsigned long buddy_idx = page_idx ^ (1 << order);

	return page + (buddy_idx - page_idx);
}

static inline unsigned long
__find_combined_index(unsigned long page_idx, unsigned int order)
{
	return (page_idx & ~(1 << order));
}

/*
 * This function checks whether a page is free && is the buddy
 * we can do coalesce a page and its buddy if
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 * (a) the buddy is not in a hole &&
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 * (b) the buddy is in the buddy system &&
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 * (c) a page and its buddy have the same order &&
 * (d) a page and its buddy are in the same zone.
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 *
 * For recording whether a page is in the buddy system, we use PG_buddy.
 * Setting, clearing, and testing PG_buddy is serialized by zone->lock.
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 *
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 * For recording page's order, we use page_private(page).
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 */
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static inline int page_is_buddy(struct page *page, struct page *buddy,
								int order)
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{
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#ifdef CONFIG_HOLES_IN_ZONE
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	if (!pfn_valid(page_to_pfn(buddy)))
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		return 0;
#endif

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	if (page_zone_id(page) != page_zone_id(buddy))
		return 0;

	if (PageBuddy(buddy) && page_order(buddy) == order) {
		BUG_ON(page_count(buddy) != 0);
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		return 1;
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	}
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	return 0;
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}

/*
 * Freeing function for a buddy system allocator.
 *
 * The concept of a buddy system is to maintain direct-mapped table
 * (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 a list of pages, which are heads of continuous
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 * free pages of length of (1 << order) and marked with PG_buddy. Page's
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 * order is recorded in page_private(page) field.
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 * 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
 */

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static inline void __free_one_page(struct page *page,
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		struct zone *zone, unsigned int order)
{
	unsigned long page_idx;
	int order_size = 1 << order;

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	if (unlikely(PageCompound(page)))
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		destroy_compound_page(page, order);

	page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);

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	VM_BUG_ON(page_idx & (order_size - 1));
	VM_BUG_ON(bad_range(zone, page));
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	__mod_zone_page_state(zone, NR_FREE_PAGES, order_size);
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	while (order < MAX_ORDER-1) {
		unsigned long combined_idx;
		struct free_area *area;
		struct page *buddy;

		buddy = __page_find_buddy(page, page_idx, order);
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		if (!page_is_buddy(page, buddy, order))
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			break;		/* Move the buddy up one level. */
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		list_del(&buddy->lru);
		area = zone->free_area + order;
		area->nr_free--;
		rmv_page_order(buddy);
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		combined_idx = __find_combined_index(page_idx, order);
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		page = page + (combined_idx - page_idx);
		page_idx = combined_idx;
		order++;
	}
	set_page_order(page, order);
	list_add(&page->lru, &zone->free_area[order].free_list);
	zone->free_area[order].nr_free++;
}

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static inline int free_pages_check(struct page *page)
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{
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	if (unlikely(page_mapcount(page) |
		(page->mapping != NULL)  |
		(page_count(page) != 0)  |
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		(page->flags & (
			1 << PG_lru	|
			1 << PG_private |
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_reclaim	|
			1 << PG_slab	|
			1 << PG_swapcache |
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			1 << PG_writeback |
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			1 << PG_reserved |
			1 << PG_buddy ))))
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		bad_page(page);
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	if (PageDirty(page))
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		__ClearPageDirty(page);
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	/*
	 * For now, we report if PG_reserved was found set, but do not
	 * clear it, and do not free the page.  But we shall soon need
	 * to do more, for when the ZERO_PAGE count wraps negative.
	 */
	return PageReserved(page);
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}

/*
 * Frees a list of pages. 
 * Assumes all pages on list are in same zone, and of same order.
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 * count is the number of pages to free.
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 *
 * If the zone was previously in an "all pages pinned" state then look to
 * see if this freeing clears that state.
 *
 * And clear the zone's pages_scanned counter, to hold off the "all pages are
 * pinned" detection logic.
 */
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static void free_pages_bulk(struct zone *zone, int count,
					struct list_head *list, int order)
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{
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	spin_lock(&zone->lock);
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	zone->all_unreclaimable = 0;
	zone->pages_scanned = 0;
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	while (count--) {
		struct page *page;

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		VM_BUG_ON(list_empty(list));
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		page = list_entry(list->prev, struct page, lru);
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		/* have to delete it as __free_one_page list manipulates */
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		list_del(&page->lru);
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		__free_one_page(page, zone, order);
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	}
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	spin_unlock(&zone->lock);
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}

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static void free_one_page(struct zone *zone, struct page *page, int order)
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{
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	spin_lock(&zone->lock);
	zone->all_unreclaimable = 0;
	zone->pages_scanned = 0;
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	__free_one_page(page, zone, order);
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	spin_unlock(&zone->lock);
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}

static void __free_pages_ok(struct page *page, unsigned int order)
{
	unsigned long flags;
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	int i;
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	int reserved = 0;
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	for (i = 0 ; i < (1 << order) ; ++i)
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		reserved += free_pages_check(page + i);
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	if (reserved)
		return;

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	if (!PageHighMem(page))
		debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
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	arch_free_page(page, order);
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	kernel_map_pages(page, 1 << order, 0);
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	local_irq_save(flags);
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	__count_vm_events(PGFREE, 1 << order);
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	free_one_page(page_zone(page), page, order);
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	local_irq_restore(flags);
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}

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/*
 * permit the bootmem allocator to evade page validation on high-order frees
 */
void fastcall __init __free_pages_bootmem(struct page *page, unsigned int order)
{
	if (order == 0) {
		__ClearPageReserved(page);
		set_page_count(page, 0);
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		set_page_refcounted(page);
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		__free_page(page);
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	} else {
		int loop;

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		prefetchw(page);
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		for (loop = 0; loop < BITS_PER_LONG; loop++) {
			struct page *p = &page[loop];

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526 527
			if (loop + 1 < BITS_PER_LONG)
				prefetchw(p + 1);
528 529 530 531
			__ClearPageReserved(p);
			set_page_count(p, 0);
		}

532
		set_page_refcounted(page);
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533
		__free_pages(page, order);
534 535 536
	}
}

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537 538 539 540 541 542 543 544 545 546 547 548 549 550 551

/*
 * The order of subdivision here is critical for the IO subsystem.
 * Please do not alter this order without good reasons and regression
 * testing. Specifically, as large blocks of memory are subdivided,
 * the order in which smaller blocks are delivered depends on the order
 * they're subdivided in this function. This is the primary factor
 * influencing the order in which pages are delivered to the IO
 * subsystem according to empirical testing, and this is also justified
 * by considering the behavior of a buddy system containing a single
 * large block of memory acted on by a series of small allocations.
 * This behavior is a critical factor in sglist merging's success.
 *
 * -- wli
 */
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552
static inline void expand(struct zone *zone, struct page *page,
L
Linus Torvalds 已提交
553 554 555 556 557 558 559 560
 	int low, int high, struct free_area *area)
{
	unsigned long size = 1 << high;

	while (high > low) {
		area--;
		high--;
		size >>= 1;
N
Nick Piggin 已提交
561
		VM_BUG_ON(bad_range(zone, &page[size]));
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		list_add(&page[size].lru, &area->free_list);
		area->nr_free++;
		set_page_order(&page[size], high);
	}
}

/*
 * This page is about to be returned from the page allocator
 */
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571
static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
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{
N
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573 574 575
	if (unlikely(page_mapcount(page) |
		(page->mapping != NULL)  |
		(page_count(page) != 0)  |
576 577
		(page->flags & (
			1 << PG_lru	|
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			1 << PG_private	|
			1 << PG_locked	|
			1 << PG_active	|
			1 << PG_dirty	|
			1 << PG_reclaim	|
583
			1 << PG_slab    |
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584
			1 << PG_swapcache |
N
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585
			1 << PG_writeback |
586 587
			1 << PG_reserved |
			1 << PG_buddy ))))
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588
		bad_page(page);
L
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589

590 591 592 593 594 595 596
	/*
	 * For now, we report if PG_reserved was found set, but do not
	 * clear it, and do not allocate the page: as a safety net.
	 */
	if (PageReserved(page))
		return 1;

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	page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
			1 << PG_referenced | 1 << PG_arch_1 |
			1 << PG_checked | 1 << PG_mappedtodisk);
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	set_page_private(page, 0);
601
	set_page_refcounted(page);
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	arch_alloc_page(page, order);
L
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	kernel_map_pages(page, 1 << order, 1);
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605 606 607 608 609 610 611

	if (gfp_flags & __GFP_ZERO)
		prep_zero_page(page, order, gfp_flags);

	if (order && (gfp_flags & __GFP_COMP))
		prep_compound_page(page, order);

612
	return 0;
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}

/* 
 * Do the hard work of removing an element from the buddy allocator.
 * Call me with the zone->lock already held.
 */
static struct page *__rmqueue(struct zone *zone, unsigned int order)
{
	struct free_area * area;
	unsigned int current_order;
	struct page *page;

	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
		area = zone->free_area + current_order;
		if (list_empty(&area->free_list))
			continue;

		page = list_entry(area->free_list.next, struct page, lru);
		list_del(&page->lru);
		rmv_page_order(page);
		area->nr_free--;
634
		__mod_zone_page_state(zone, NR_FREE_PAGES, - (1UL << order));
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		expand(zone, page, order, current_order, area);
		return page;
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	}

	return NULL;
}

/* 
 * Obtain a specified number of elements from the buddy allocator, all under
 * a single hold of the lock, for efficiency.  Add them to the supplied list.
 * Returns the number of new pages which were placed at *list.
 */
static int rmqueue_bulk(struct zone *zone, unsigned int order, 
			unsigned long count, struct list_head *list)
{
	int i;
	
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	spin_lock(&zone->lock);
L
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653
	for (i = 0; i < count; ++i) {
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654 655
		struct page *page = __rmqueue(zone, order);
		if (unlikely(page == NULL))
L
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656 657 658
			break;
		list_add_tail(&page->lru, list);
	}
N
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	spin_unlock(&zone->lock);
N
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660
	return i;
L
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}

663
#ifdef CONFIG_NUMA
664 665
/*
 * Called from the slab reaper to drain pagesets on a particular node that
666
 * belongs to the currently executing processor.
667 668
 * Note that this function must be called with the thread pinned to
 * a single processor.
669 670
 */
void drain_node_pages(int nodeid)
671
{
672 673
	int i;
	enum zone_type z;
674 675
	unsigned long flags;

676 677
	for (z = 0; z < MAX_NR_ZONES; z++) {
		struct zone *zone = NODE_DATA(nodeid)->node_zones + z;
678 679
		struct per_cpu_pageset *pset;

680 681 682
		if (!populated_zone(zone))
			continue;

N
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683
		pset = zone_pcp(zone, smp_processor_id());
684 685 686 687
		for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
			struct per_cpu_pages *pcp;

			pcp = &pset->pcp[i];
688
			if (pcp->count) {
689 690
				int to_drain;

691
				local_irq_save(flags);
692 693 694 695 696 697
				if (pcp->count >= pcp->batch)
					to_drain = pcp->batch;
				else
					to_drain = pcp->count;
				free_pages_bulk(zone, to_drain, &pcp->list, 0);
				pcp->count -= to_drain;
698 699
				local_irq_restore(flags);
			}
700 701 702 703 704
		}
	}
}
#endif

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static void __drain_pages(unsigned int cpu)
{
N
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707
	unsigned long flags;
L
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	struct zone *zone;
	int i;

	for_each_zone(zone) {
		struct per_cpu_pageset *pset;

714 715 716
		if (!populated_zone(zone))
			continue;

717
		pset = zone_pcp(zone, cpu);
L
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		for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
			struct per_cpu_pages *pcp;

			pcp = &pset->pcp[i];
N
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			local_irq_save(flags);
N
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723 724
			free_pages_bulk(zone, pcp->count, &pcp->list, 0);
			pcp->count = 0;
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725
			local_irq_restore(flags);
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		}
	}
}

#ifdef CONFIG_PM

void mark_free_pages(struct zone *zone)
{
734 735
	unsigned long pfn, max_zone_pfn;
	unsigned long flags;
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736 737 738 739 740 741 742
	int order;
	struct list_head *curr;

	if (!zone->spanned_pages)
		return;

	spin_lock_irqsave(&zone->lock, flags);
743 744 745 746 747 748 749 750 751

	max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
		if (pfn_valid(pfn)) {
			struct page *page = pfn_to_page(pfn);

			if (!PageNosave(page))
				ClearPageNosaveFree(page);
		}
L
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	for (order = MAX_ORDER - 1; order >= 0; --order)
		list_for_each(curr, &zone->free_area[order].free_list) {
755
			unsigned long i;
L
Linus Torvalds 已提交
756

757 758 759 760
			pfn = page_to_pfn(list_entry(curr, struct page, lru));
			for (i = 0; i < (1UL << order); i++)
				SetPageNosaveFree(pfn_to_page(pfn + i));
		}
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761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788

	spin_unlock_irqrestore(&zone->lock, flags);
}

/*
 * Spill all of this CPU's per-cpu pages back into the buddy allocator.
 */
void drain_local_pages(void)
{
	unsigned long flags;

	local_irq_save(flags);	
	__drain_pages(smp_processor_id());
	local_irq_restore(flags);	
}
#endif /* CONFIG_PM */

/*
 * Free a 0-order page
 */
static void fastcall free_hot_cold_page(struct page *page, int cold)
{
	struct zone *zone = page_zone(page);
	struct per_cpu_pages *pcp;
	unsigned long flags;

	if (PageAnon(page))
		page->mapping = NULL;
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789
	if (free_pages_check(page))
790 791
		return;

N
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792 793
	if (!PageHighMem(page))
		debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
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794
	arch_free_page(page, 0);
795 796
	kernel_map_pages(page, 1, 0);

797
	pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
L
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798
	local_irq_save(flags);
799
	__count_vm_event(PGFREE);
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	list_add(&page->lru, &pcp->list);
	pcp->count++;
N
Nick Piggin 已提交
802 803 804 805
	if (pcp->count >= pcp->high) {
		free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
		pcp->count -= pcp->batch;
	}
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	local_irq_restore(flags);
	put_cpu();
}

void fastcall free_hot_page(struct page *page)
{
	free_hot_cold_page(page, 0);
}
	
void fastcall free_cold_page(struct page *page)
{
	free_hot_cold_page(page, 1);
}

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Nick Piggin 已提交
820 821 822 823 824 825 826 827 828 829 830 831
/*
 * split_page takes a non-compound higher-order page, and splits it into
 * n (1<<order) sub-pages: page[0..n]
 * Each sub-page must be freed individually.
 *
 * Note: this is probably too low level an operation for use in drivers.
 * Please consult with lkml before using this in your driver.
 */
void split_page(struct page *page, unsigned int order)
{
	int i;

N
Nick Piggin 已提交
832 833
	VM_BUG_ON(PageCompound(page));
	VM_BUG_ON(!page_count(page));
834 835
	for (i = 1; i < (1 << order); i++)
		set_page_refcounted(page + i);
N
Nick Piggin 已提交
836 837
}

L
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838 839 840 841 842
/*
 * Really, prep_compound_page() should be called from __rmqueue_bulk().  But
 * we cheat by calling it from here, in the order > 0 path.  Saves a branch
 * or two.
 */
N
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843 844
static struct page *buffered_rmqueue(struct zonelist *zonelist,
			struct zone *zone, int order, gfp_t gfp_flags)
L
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845 846
{
	unsigned long flags;
847
	struct page *page;
L
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848
	int cold = !!(gfp_flags & __GFP_COLD);
N
Nick Piggin 已提交
849
	int cpu;
L
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850

851
again:
N
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852
	cpu  = get_cpu();
N
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853
	if (likely(order == 0)) {
L
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854 855
		struct per_cpu_pages *pcp;

N
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856
		pcp = &zone_pcp(zone, cpu)->pcp[cold];
L
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857
		local_irq_save(flags);
N
Nick Piggin 已提交
858
		if (!pcp->count) {
859
			pcp->count = rmqueue_bulk(zone, 0,
L
Linus Torvalds 已提交
860
						pcp->batch, &pcp->list);
N
Nick Piggin 已提交
861 862
			if (unlikely(!pcp->count))
				goto failed;
L
Linus Torvalds 已提交
863
		}
N
Nick Piggin 已提交
864 865 866
		page = list_entry(pcp->list.next, struct page, lru);
		list_del(&page->lru);
		pcp->count--;
R
Rohit Seth 已提交
867
	} else {
L
Linus Torvalds 已提交
868 869
		spin_lock_irqsave(&zone->lock, flags);
		page = __rmqueue(zone, order);
N
Nick Piggin 已提交
870 871 872
		spin_unlock(&zone->lock);
		if (!page)
			goto failed;
L
Linus Torvalds 已提交
873 874
	}

875
	__count_zone_vm_events(PGALLOC, zone, 1 << order);
876
	zone_statistics(zonelist, zone);
N
Nick Piggin 已提交
877 878
	local_irq_restore(flags);
	put_cpu();
L
Linus Torvalds 已提交
879

N
Nick Piggin 已提交
880
	VM_BUG_ON(bad_range(zone, page));
N
Nick Piggin 已提交
881
	if (prep_new_page(page, order, gfp_flags))
N
Nick Piggin 已提交
882
		goto again;
L
Linus Torvalds 已提交
883
	return page;
N
Nick Piggin 已提交
884 885 886 887 888

failed:
	local_irq_restore(flags);
	put_cpu();
	return NULL;
L
Linus Torvalds 已提交
889 890
}

R
Rohit Seth 已提交
891
#define ALLOC_NO_WATERMARKS	0x01 /* don't check watermarks at all */
892 893 894 895 896 897
#define ALLOC_WMARK_MIN		0x02 /* use pages_min watermark */
#define ALLOC_WMARK_LOW		0x04 /* use pages_low watermark */
#define ALLOC_WMARK_HIGH	0x08 /* use pages_high watermark */
#define ALLOC_HARDER		0x10 /* try to alloc harder */
#define ALLOC_HIGH		0x20 /* __GFP_HIGH set */
#define ALLOC_CPUSET		0x40 /* check for correct cpuset */
R
Rohit Seth 已提交
898

899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915
#ifdef CONFIG_FAIL_PAGE_ALLOC

static struct fail_page_alloc_attr {
	struct fault_attr attr;

	u32 ignore_gfp_highmem;
	u32 ignore_gfp_wait;

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS

	struct dentry *ignore_gfp_highmem_file;
	struct dentry *ignore_gfp_wait_file;

#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

} fail_page_alloc = {
	.attr = FAULT_ATTR_INITIALIZER,
916 917
	.ignore_gfp_wait = 1,
	.ignore_gfp_highmem = 1,
918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983
};

static int __init setup_fail_page_alloc(char *str)
{
	return setup_fault_attr(&fail_page_alloc.attr, str);
}
__setup("fail_page_alloc=", setup_fail_page_alloc);

static int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
	if (gfp_mask & __GFP_NOFAIL)
		return 0;
	if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
		return 0;
	if (fail_page_alloc.ignore_gfp_wait && (gfp_mask & __GFP_WAIT))
		return 0;

	return should_fail(&fail_page_alloc.attr, 1 << order);
}

#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS

static int __init fail_page_alloc_debugfs(void)
{
	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
	struct dentry *dir;
	int err;

	err = init_fault_attr_dentries(&fail_page_alloc.attr,
				       "fail_page_alloc");
	if (err)
		return err;
	dir = fail_page_alloc.attr.dentries.dir;

	fail_page_alloc.ignore_gfp_wait_file =
		debugfs_create_bool("ignore-gfp-wait", mode, dir,
				      &fail_page_alloc.ignore_gfp_wait);

	fail_page_alloc.ignore_gfp_highmem_file =
		debugfs_create_bool("ignore-gfp-highmem", mode, dir,
				      &fail_page_alloc.ignore_gfp_highmem);

	if (!fail_page_alloc.ignore_gfp_wait_file ||
			!fail_page_alloc.ignore_gfp_highmem_file) {
		err = -ENOMEM;
		debugfs_remove(fail_page_alloc.ignore_gfp_wait_file);
		debugfs_remove(fail_page_alloc.ignore_gfp_highmem_file);
		cleanup_fault_attr_dentries(&fail_page_alloc.attr);
	}

	return err;
}

late_initcall(fail_page_alloc_debugfs);

#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

#else /* CONFIG_FAIL_PAGE_ALLOC */

static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
	return 0;
}

#endif /* CONFIG_FAIL_PAGE_ALLOC */

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984 985 986 987 988
/*
 * Return 1 if free pages are above 'mark'. This takes into account the order
 * of the allocation.
 */
int zone_watermark_ok(struct zone *z, int order, unsigned long mark,
R
Rohit Seth 已提交
989
		      int classzone_idx, int alloc_flags)
L
Linus Torvalds 已提交
990 991
{
	/* free_pages my go negative - that's OK */
992 993
	long min = mark;
	long free_pages = zone_page_state(z, NR_FREE_PAGES) - (1 << order) + 1;
L
Linus Torvalds 已提交
994 995
	int o;

R
Rohit Seth 已提交
996
	if (alloc_flags & ALLOC_HIGH)
L
Linus Torvalds 已提交
997
		min -= min / 2;
R
Rohit Seth 已提交
998
	if (alloc_flags & ALLOC_HARDER)
L
Linus Torvalds 已提交
999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015
		min -= min / 4;

	if (free_pages <= min + z->lowmem_reserve[classzone_idx])
		return 0;
	for (o = 0; o < order; o++) {
		/* At the next order, this order's pages become unavailable */
		free_pages -= z->free_area[o].nr_free << o;

		/* Require fewer higher order pages to be free */
		min >>= 1;

		if (free_pages <= min)
			return 0;
	}
	return 1;
}

1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135
#ifdef CONFIG_NUMA
/*
 * zlc_setup - Setup for "zonelist cache".  Uses cached zone data to
 * skip over zones that are not allowed by the cpuset, or that have
 * been recently (in last second) found to be nearly full.  See further
 * comments in mmzone.h.  Reduces cache footprint of zonelist scans
 * that have to skip over alot of full or unallowed zones.
 *
 * If the zonelist cache is present in the passed in zonelist, then
 * returns a pointer to the allowed node mask (either the current
 * tasks mems_allowed, or node_online_map.)
 *
 * If the zonelist cache is not available for this zonelist, does
 * nothing and returns NULL.
 *
 * If the fullzones BITMAP in the zonelist cache is stale (more than
 * a second since last zap'd) then we zap it out (clear its bits.)
 *
 * We hold off even calling zlc_setup, until after we've checked the
 * first zone in the zonelist, on the theory that most allocations will
 * be satisfied from that first zone, so best to examine that zone as
 * quickly as we can.
 */
static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
{
	struct zonelist_cache *zlc;	/* cached zonelist speedup info */
	nodemask_t *allowednodes;	/* zonelist_cache approximation */

	zlc = zonelist->zlcache_ptr;
	if (!zlc)
		return NULL;

	if (jiffies - zlc->last_full_zap > 1 * HZ) {
		bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
		zlc->last_full_zap = jiffies;
	}

	allowednodes = !in_interrupt() && (alloc_flags & ALLOC_CPUSET) ?
					&cpuset_current_mems_allowed :
					&node_online_map;
	return allowednodes;
}

/*
 * Given 'z' scanning a zonelist, run a couple of quick checks to see
 * if it is worth looking at further for free memory:
 *  1) Check that the zone isn't thought to be full (doesn't have its
 *     bit set in the zonelist_cache fullzones BITMAP).
 *  2) Check that the zones node (obtained from the zonelist_cache
 *     z_to_n[] mapping) is allowed in the passed in allowednodes mask.
 * Return true (non-zero) if zone is worth looking at further, or
 * else return false (zero) if it is not.
 *
 * This check -ignores- the distinction between various watermarks,
 * such as GFP_HIGH, GFP_ATOMIC, PF_MEMALLOC, ...  If a zone is
 * found to be full for any variation of these watermarks, it will
 * be considered full for up to one second by all requests, unless
 * we are so low on memory on all allowed nodes that we are forced
 * into the second scan of the zonelist.
 *
 * In the second scan we ignore this zonelist cache and exactly
 * apply the watermarks to all zones, even it is slower to do so.
 * We are low on memory in the second scan, and should leave no stone
 * unturned looking for a free page.
 */
static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zone **z,
						nodemask_t *allowednodes)
{
	struct zonelist_cache *zlc;	/* cached zonelist speedup info */
	int i;				/* index of *z in zonelist zones */
	int n;				/* node that zone *z is on */

	zlc = zonelist->zlcache_ptr;
	if (!zlc)
		return 1;

	i = z - zonelist->zones;
	n = zlc->z_to_n[i];

	/* This zone is worth trying if it is allowed but not full */
	return node_isset(n, *allowednodes) && !test_bit(i, zlc->fullzones);
}

/*
 * Given 'z' scanning a zonelist, set the corresponding bit in
 * zlc->fullzones, so that subsequent attempts to allocate a page
 * from that zone don't waste time re-examining it.
 */
static void zlc_mark_zone_full(struct zonelist *zonelist, struct zone **z)
{
	struct zonelist_cache *zlc;	/* cached zonelist speedup info */
	int i;				/* index of *z in zonelist zones */

	zlc = zonelist->zlcache_ptr;
	if (!zlc)
		return;

	i = z - zonelist->zones;

	set_bit(i, zlc->fullzones);
}

#else	/* CONFIG_NUMA */

static nodemask_t *zlc_setup(struct zonelist *zonelist, int alloc_flags)
{
	return NULL;
}

static int zlc_zone_worth_trying(struct zonelist *zonelist, struct zone **z,
				nodemask_t *allowednodes)
{
	return 1;
}

static void zlc_mark_zone_full(struct zonelist *zonelist, struct zone **z)
{
}
#endif	/* CONFIG_NUMA */

R
Rohit Seth 已提交
1136
/*
1137
 * get_page_from_freelist goes through the zonelist trying to allocate
R
Rohit Seth 已提交
1138 1139 1140 1141 1142
 * a page.
 */
static struct page *
get_page_from_freelist(gfp_t gfp_mask, unsigned int order,
		struct zonelist *zonelist, int alloc_flags)
M
Martin Hicks 已提交
1143
{
1144
	struct zone **z;
R
Rohit Seth 已提交
1145
	struct page *page = NULL;
1146
	int classzone_idx = zone_idx(zonelist->zones[0]);
1147
	struct zone *zone;
1148 1149 1150
	nodemask_t *allowednodes = NULL;/* zonelist_cache approximation */
	int zlc_active = 0;		/* set if using zonelist_cache */
	int did_zlc_setup = 0;		/* just call zlc_setup() one time */
R
Rohit Seth 已提交
1151

1152
zonelist_scan:
R
Rohit Seth 已提交
1153
	/*
1154
	 * Scan zonelist, looking for a zone with enough free.
R
Rohit Seth 已提交
1155 1156
	 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
	 */
1157 1158
	z = zonelist->zones;

R
Rohit Seth 已提交
1159
	do {
1160 1161 1162
		if (NUMA_BUILD && zlc_active &&
			!zlc_zone_worth_trying(zonelist, z, allowednodes))
				continue;
1163
		zone = *z;
1164
		if (unlikely(NUMA_BUILD && (gfp_mask & __GFP_THISNODE) &&
1165
			zone->zone_pgdat != zonelist->zones[0]->zone_pgdat))
1166
				break;
R
Rohit Seth 已提交
1167
		if ((alloc_flags & ALLOC_CPUSET) &&
1168
			!cpuset_zone_allowed_softwall(zone, gfp_mask))
1169
				goto try_next_zone;
R
Rohit Seth 已提交
1170 1171

		if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
1172 1173
			unsigned long mark;
			if (alloc_flags & ALLOC_WMARK_MIN)
1174
				mark = zone->pages_min;
1175
			else if (alloc_flags & ALLOC_WMARK_LOW)
1176
				mark = zone->pages_low;
1177
			else
1178
				mark = zone->pages_high;
1179 1180
			if (!zone_watermark_ok(zone, order, mark,
				    classzone_idx, alloc_flags)) {
1181
				if (!zone_reclaim_mode ||
1182
				    !zone_reclaim(zone, gfp_mask, order))
1183
					goto this_zone_full;
1184
			}
R
Rohit Seth 已提交
1185 1186
		}

1187
		page = buffered_rmqueue(zonelist, zone, order, gfp_mask);
1188
		if (page)
R
Rohit Seth 已提交
1189
			break;
1190 1191 1192 1193 1194 1195 1196 1197 1198 1199
this_zone_full:
		if (NUMA_BUILD)
			zlc_mark_zone_full(zonelist, z);
try_next_zone:
		if (NUMA_BUILD && !did_zlc_setup) {
			/* we do zlc_setup after the first zone is tried */
			allowednodes = zlc_setup(zonelist, alloc_flags);
			zlc_active = 1;
			did_zlc_setup = 1;
		}
R
Rohit Seth 已提交
1200
	} while (*(++z) != NULL);
1201 1202 1203 1204 1205 1206

	if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
		/* Disable zlc cache for second zonelist scan */
		zlc_active = 0;
		goto zonelist_scan;
	}
R
Rohit Seth 已提交
1207
	return page;
M
Martin Hicks 已提交
1208 1209
}

L
Linus Torvalds 已提交
1210 1211 1212 1213
/*
 * This is the 'heart' of the zoned buddy allocator.
 */
struct page * fastcall
A
Al Viro 已提交
1214
__alloc_pages(gfp_t gfp_mask, unsigned int order,
L
Linus Torvalds 已提交
1215 1216
		struct zonelist *zonelist)
{
A
Al Viro 已提交
1217
	const gfp_t wait = gfp_mask & __GFP_WAIT;
R
Rohit Seth 已提交
1218
	struct zone **z;
L
Linus Torvalds 已提交
1219 1220 1221 1222
	struct page *page;
	struct reclaim_state reclaim_state;
	struct task_struct *p = current;
	int do_retry;
R
Rohit Seth 已提交
1223
	int alloc_flags;
L
Linus Torvalds 已提交
1224 1225 1226 1227
	int did_some_progress;

	might_sleep_if(wait);

1228 1229 1230
	if (should_fail_alloc_page(gfp_mask, order))
		return NULL;

1231
restart:
R
Rohit Seth 已提交
1232
	z = zonelist->zones;  /* the list of zones suitable for gfp_mask */
L
Linus Torvalds 已提交
1233

R
Rohit Seth 已提交
1234
	if (unlikely(*z == NULL)) {
L
Linus Torvalds 已提交
1235 1236 1237
		/* Should this ever happen?? */
		return NULL;
	}
1238

R
Rohit Seth 已提交
1239
	page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
1240
				zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET);
R
Rohit Seth 已提交
1241 1242
	if (page)
		goto got_pg;
L
Linus Torvalds 已提交
1243

1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254
	/*
	 * GFP_THISNODE (meaning __GFP_THISNODE, __GFP_NORETRY and
	 * __GFP_NOWARN set) should not cause reclaim since the subsystem
	 * (f.e. slab) using GFP_THISNODE may choose to trigger reclaim
	 * using a larger set of nodes after it has established that the
	 * allowed per node queues are empty and that nodes are
	 * over allocated.
	 */
	if (NUMA_BUILD && (gfp_mask & GFP_THISNODE) == GFP_THISNODE)
		goto nopage;

1255
	for (z = zonelist->zones; *z; z++)
1256
		wakeup_kswapd(*z, order);
L
Linus Torvalds 已提交
1257

1258
	/*
R
Rohit Seth 已提交
1259 1260 1261 1262 1263 1264
	 * OK, we're below the kswapd watermark and have kicked background
	 * reclaim. Now things get more complex, so set up alloc_flags according
	 * to how we want to proceed.
	 *
	 * The caller may dip into page reserves a bit more if the caller
	 * cannot run direct reclaim, or if the caller has realtime scheduling
P
Paul Jackson 已提交
1265 1266
	 * policy or is asking for __GFP_HIGH memory.  GFP_ATOMIC requests will
	 * set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
1267
	 */
1268
	alloc_flags = ALLOC_WMARK_MIN;
R
Rohit Seth 已提交
1269 1270 1271 1272
	if ((unlikely(rt_task(p)) && !in_interrupt()) || !wait)
		alloc_flags |= ALLOC_HARDER;
	if (gfp_mask & __GFP_HIGH)
		alloc_flags |= ALLOC_HIGH;
1273 1274
	if (wait)
		alloc_flags |= ALLOC_CPUSET;
L
Linus Torvalds 已提交
1275 1276 1277

	/*
	 * Go through the zonelist again. Let __GFP_HIGH and allocations
R
Rohit Seth 已提交
1278
	 * coming from realtime tasks go deeper into reserves.
L
Linus Torvalds 已提交
1279 1280 1281
	 *
	 * This is the last chance, in general, before the goto nopage.
	 * Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
1282
	 * See also cpuset_zone_allowed() comment in kernel/cpuset.c.
L
Linus Torvalds 已提交
1283
	 */
R
Rohit Seth 已提交
1284 1285 1286
	page = get_page_from_freelist(gfp_mask, order, zonelist, alloc_flags);
	if (page)
		goto got_pg;
L
Linus Torvalds 已提交
1287 1288

	/* This allocation should allow future memory freeing. */
1289

1290
rebalance:
1291 1292 1293
	if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE)))
			&& !in_interrupt()) {
		if (!(gfp_mask & __GFP_NOMEMALLOC)) {
K
Kirill Korotaev 已提交
1294
nofail_alloc:
1295
			/* go through the zonelist yet again, ignoring mins */
R
Rohit Seth 已提交
1296
			page = get_page_from_freelist(gfp_mask, order,
1297
				zonelist, ALLOC_NO_WATERMARKS);
R
Rohit Seth 已提交
1298 1299
			if (page)
				goto got_pg;
K
Kirill Korotaev 已提交
1300
			if (gfp_mask & __GFP_NOFAIL) {
1301
				congestion_wait(WRITE, HZ/50);
K
Kirill Korotaev 已提交
1302 1303
				goto nofail_alloc;
			}
L
Linus Torvalds 已提交
1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314
		}
		goto nopage;
	}

	/* Atomic allocations - we can't balance anything */
	if (!wait)
		goto nopage;

	cond_resched();

	/* We now go into synchronous reclaim */
1315
	cpuset_memory_pressure_bump();
L
Linus Torvalds 已提交
1316 1317 1318 1319
	p->flags |= PF_MEMALLOC;
	reclaim_state.reclaimed_slab = 0;
	p->reclaim_state = &reclaim_state;

R
Rohit Seth 已提交
1320
	did_some_progress = try_to_free_pages(zonelist->zones, gfp_mask);
L
Linus Torvalds 已提交
1321 1322 1323 1324 1325 1326 1327

	p->reclaim_state = NULL;
	p->flags &= ~PF_MEMALLOC;

	cond_resched();

	if (likely(did_some_progress)) {
R
Rohit Seth 已提交
1328 1329 1330 1331
		page = get_page_from_freelist(gfp_mask, order,
						zonelist, alloc_flags);
		if (page)
			goto got_pg;
L
Linus Torvalds 已提交
1332 1333 1334 1335 1336 1337 1338
	} else if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
		/*
		 * Go through the zonelist yet one more time, keep
		 * very high watermark here, this is only to catch
		 * a parallel oom killing, we must fail if we're still
		 * under heavy pressure.
		 */
R
Rohit Seth 已提交
1339
		page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
1340
				zonelist, ALLOC_WMARK_HIGH|ALLOC_CPUSET);
R
Rohit Seth 已提交
1341 1342
		if (page)
			goto got_pg;
L
Linus Torvalds 已提交
1343

1344
		out_of_memory(zonelist, gfp_mask, order);
L
Linus Torvalds 已提交
1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362
		goto restart;
	}

	/*
	 * Don't let big-order allocations loop unless the caller explicitly
	 * requests that.  Wait for some write requests to complete then retry.
	 *
	 * In this implementation, __GFP_REPEAT means __GFP_NOFAIL for order
	 * <= 3, but that may not be true in other implementations.
	 */
	do_retry = 0;
	if (!(gfp_mask & __GFP_NORETRY)) {
		if ((order <= 3) || (gfp_mask & __GFP_REPEAT))
			do_retry = 1;
		if (gfp_mask & __GFP_NOFAIL)
			do_retry = 1;
	}
	if (do_retry) {
1363
		congestion_wait(WRITE, HZ/50);
L
Linus Torvalds 已提交
1364 1365 1366 1367 1368 1369 1370 1371 1372
		goto rebalance;
	}

nopage:
	if (!(gfp_mask & __GFP_NOWARN) && printk_ratelimit()) {
		printk(KERN_WARNING "%s: page allocation failure."
			" order:%d, mode:0x%x\n",
			p->comm, order, gfp_mask);
		dump_stack();
J
Janet Morgan 已提交
1373
		show_mem();
L
Linus Torvalds 已提交
1374 1375 1376 1377 1378 1379 1380 1381 1382 1383
	}
got_pg:
	return page;
}

EXPORT_SYMBOL(__alloc_pages);

/*
 * Common helper functions.
 */
A
Al Viro 已提交
1384
fastcall unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
L
Linus Torvalds 已提交
1385 1386 1387 1388 1389 1390 1391 1392 1393 1394
{
	struct page * page;
	page = alloc_pages(gfp_mask, order);
	if (!page)
		return 0;
	return (unsigned long) page_address(page);
}

EXPORT_SYMBOL(__get_free_pages);

A
Al Viro 已提交
1395
fastcall unsigned long get_zeroed_page(gfp_t gfp_mask)
L
Linus Torvalds 已提交
1396 1397 1398 1399 1400 1401 1402
{
	struct page * page;

	/*
	 * get_zeroed_page() returns a 32-bit address, which cannot represent
	 * a highmem page
	 */
N
Nick Piggin 已提交
1403
	VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
L
Linus Torvalds 已提交
1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422

	page = alloc_pages(gfp_mask | __GFP_ZERO, 0);
	if (page)
		return (unsigned long) page_address(page);
	return 0;
}

EXPORT_SYMBOL(get_zeroed_page);

void __pagevec_free(struct pagevec *pvec)
{
	int i = pagevec_count(pvec);

	while (--i >= 0)
		free_hot_cold_page(pvec->pages[i], pvec->cold);
}

fastcall void __free_pages(struct page *page, unsigned int order)
{
N
Nick Piggin 已提交
1423
	if (put_page_testzero(page)) {
L
Linus Torvalds 已提交
1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435
		if (order == 0)
			free_hot_page(page);
		else
			__free_pages_ok(page, order);
	}
}

EXPORT_SYMBOL(__free_pages);

fastcall void free_pages(unsigned long addr, unsigned int order)
{
	if (addr != 0) {
N
Nick Piggin 已提交
1436
		VM_BUG_ON(!virt_addr_valid((void *)addr));
L
Linus Torvalds 已提交
1437 1438 1439 1440 1441 1442 1443 1444
		__free_pages(virt_to_page((void *)addr), order);
	}
}

EXPORT_SYMBOL(free_pages);

static unsigned int nr_free_zone_pages(int offset)
{
1445 1446
	/* Just pick one node, since fallback list is circular */
	pg_data_t *pgdat = NODE_DATA(numa_node_id());
L
Linus Torvalds 已提交
1447 1448
	unsigned int sum = 0;

1449 1450 1451
	struct zonelist *zonelist = pgdat->node_zonelists + offset;
	struct zone **zonep = zonelist->zones;
	struct zone *zone;
L
Linus Torvalds 已提交
1452

1453 1454 1455 1456 1457
	for (zone = *zonep++; zone; zone = *zonep++) {
		unsigned long size = zone->present_pages;
		unsigned long high = zone->pages_high;
		if (size > high)
			sum += size - high;
L
Linus Torvalds 已提交
1458 1459 1460 1461 1462 1463 1464 1465 1466 1467
	}

	return sum;
}

/*
 * Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
 */
unsigned int nr_free_buffer_pages(void)
{
A
Al Viro 已提交
1468
	return nr_free_zone_pages(gfp_zone(GFP_USER));
L
Linus Torvalds 已提交
1469 1470 1471 1472 1473 1474 1475
}

/*
 * Amount of free RAM allocatable within all zones
 */
unsigned int nr_free_pagecache_pages(void)
{
A
Al Viro 已提交
1476
	return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER));
L
Linus Torvalds 已提交
1477
}
1478 1479

static inline void show_node(struct zone *zone)
L
Linus Torvalds 已提交
1480
{
1481
	if (NUMA_BUILD)
1482
		printk("Node %d ", zone_to_nid(zone));
L
Linus Torvalds 已提交
1483 1484 1485 1486 1487 1488
}

void si_meminfo(struct sysinfo *val)
{
	val->totalram = totalram_pages;
	val->sharedram = 0;
1489
	val->freeram = global_page_state(NR_FREE_PAGES);
L
Linus Torvalds 已提交
1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503
	val->bufferram = nr_blockdev_pages();
	val->totalhigh = totalhigh_pages;
	val->freehigh = nr_free_highpages();
	val->mem_unit = PAGE_SIZE;
}

EXPORT_SYMBOL(si_meminfo);

#ifdef CONFIG_NUMA
void si_meminfo_node(struct sysinfo *val, int nid)
{
	pg_data_t *pgdat = NODE_DATA(nid);

	val->totalram = pgdat->node_present_pages;
1504
	val->freeram = node_page_state(nid, NR_FREE_PAGES);
1505
#ifdef CONFIG_HIGHMEM
L
Linus Torvalds 已提交
1506
	val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
1507 1508
	val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
			NR_FREE_PAGES);
1509 1510 1511 1512
#else
	val->totalhigh = 0;
	val->freehigh = 0;
#endif
L
Linus Torvalds 已提交
1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525
	val->mem_unit = PAGE_SIZE;
}
#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(void)
{
1526
	int cpu;
L
Linus Torvalds 已提交
1527 1528 1529
	struct zone *zone;

	for_each_zone(zone) {
1530
		if (!populated_zone(zone))
L
Linus Torvalds 已提交
1531
			continue;
1532 1533 1534

		show_node(zone);
		printk("%s per-cpu:\n", zone->name);
L
Linus Torvalds 已提交
1535

1536
		for_each_online_cpu(cpu) {
L
Linus Torvalds 已提交
1537 1538
			struct per_cpu_pageset *pageset;

1539
			pageset = zone_pcp(zone, cpu);
L
Linus Torvalds 已提交
1540

1541 1542 1543 1544 1545 1546
			printk("CPU %4d: Hot: hi:%5d, btch:%4d usd:%4d   "
			       "Cold: hi:%5d, btch:%4d usd:%4d\n",
			       cpu, pageset->pcp[0].high,
			       pageset->pcp[0].batch, pageset->pcp[0].count,
			       pageset->pcp[1].high, pageset->pcp[1].batch,
			       pageset->pcp[1].count);
L
Linus Torvalds 已提交
1547 1548 1549
		}
	}

1550
	printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu\n"
1551
		" free:%lu slab:%lu mapped:%lu pagetables:%lu bounce:%lu\n",
1552 1553
		global_page_state(NR_ACTIVE),
		global_page_state(NR_INACTIVE),
1554
		global_page_state(NR_FILE_DIRTY),
1555
		global_page_state(NR_WRITEBACK),
1556
		global_page_state(NR_UNSTABLE_NFS),
1557
		global_page_state(NR_FREE_PAGES),
1558 1559
		global_page_state(NR_SLAB_RECLAIMABLE) +
			global_page_state(NR_SLAB_UNRECLAIMABLE),
1560
		global_page_state(NR_FILE_MAPPED),
1561 1562
		global_page_state(NR_PAGETABLE),
		global_page_state(NR_BOUNCE));
L
Linus Torvalds 已提交
1563 1564 1565 1566

	for_each_zone(zone) {
		int i;

1567 1568 1569
		if (!populated_zone(zone))
			continue;

L
Linus Torvalds 已提交
1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582
		show_node(zone);
		printk("%s"
			" free:%lukB"
			" min:%lukB"
			" low:%lukB"
			" high:%lukB"
			" active:%lukB"
			" inactive:%lukB"
			" present:%lukB"
			" pages_scanned:%lu"
			" all_unreclaimable? %s"
			"\n",
			zone->name,
1583
			K(zone_page_state(zone, NR_FREE_PAGES)),
L
Linus Torvalds 已提交
1584 1585 1586
			K(zone->pages_min),
			K(zone->pages_low),
			K(zone->pages_high),
1587 1588
			K(zone_page_state(zone, NR_ACTIVE)),
			K(zone_page_state(zone, NR_INACTIVE)),
L
Linus Torvalds 已提交
1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599
			K(zone->present_pages),
			zone->pages_scanned,
			(zone->all_unreclaimable ? "yes" : "no")
			);
		printk("lowmem_reserve[]:");
		for (i = 0; i < MAX_NR_ZONES; i++)
			printk(" %lu", zone->lowmem_reserve[i]);
		printk("\n");
	}

	for_each_zone(zone) {
1600
 		unsigned long nr[MAX_ORDER], flags, order, total = 0;
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1602 1603 1604
		if (!populated_zone(zone))
			continue;

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		show_node(zone);
		printk("%s: ", zone->name);

		spin_lock_irqsave(&zone->lock, flags);
		for (order = 0; order < MAX_ORDER; order++) {
1610 1611
			nr[order] = zone->free_area[order].nr_free;
			total += nr[order] << order;
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1612 1613
		}
		spin_unlock_irqrestore(&zone->lock, flags);
1614 1615
		for (order = 0; order < MAX_ORDER; order++)
			printk("%lu*%lukB ", nr[order], K(1UL) << order);
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		printk("= %lukB\n", K(total));
	}

	show_swap_cache_info();
}

/*
 * Builds allocation fallback zone lists.
1624 1625
 *
 * Add all populated zones of a node to the zonelist.
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1626
 */
1627
static int __meminit build_zonelists_node(pg_data_t *pgdat,
1628
			struct zonelist *zonelist, int nr_zones, enum zone_type zone_type)
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1629
{
1630 1631
	struct zone *zone;

1632
	BUG_ON(zone_type >= MAX_NR_ZONES);
1633
	zone_type++;
1634 1635

	do {
1636
		zone_type--;
1637
		zone = pgdat->node_zones + zone_type;
1638
		if (populated_zone(zone)) {
1639 1640
			zonelist->zones[nr_zones++] = zone;
			check_highest_zone(zone_type);
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1641
		}
1642

1643
	} while (zone_type);
1644
	return nr_zones;
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1645 1646 1647 1648
}

#ifdef CONFIG_NUMA
#define MAX_NODE_LOAD (num_online_nodes())
1649
static int __meminitdata node_load[MAX_NUMNODES];
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/**
1651
 * find_next_best_node - find the next node that should appear in a given node's fallback list
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1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663
 * @node: node whose fallback list we're appending
 * @used_node_mask: nodemask_t of already used nodes
 *
 * We use a number of factors to determine which is the next node that should
 * appear on a given node's fallback list.  The node should not have appeared
 * already in @node's fallback list, and it should be the next closest node
 * according to the distance array (which contains arbitrary distance values
 * from each node to each node in the system), and should also prefer nodes
 * with no CPUs, since presumably they'll have very little allocation pressure
 * on them otherwise.
 * It returns -1 if no node is found.
 */
1664
static int __meminit find_next_best_node(int node, nodemask_t *used_node_mask)
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{
1666
	int n, val;
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	int min_val = INT_MAX;
	int best_node = -1;

1670 1671 1672 1673 1674
	/* Use the local node if we haven't already */
	if (!node_isset(node, *used_node_mask)) {
		node_set(node, *used_node_mask);
		return node;
	}
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1676 1677
	for_each_online_node(n) {
		cpumask_t tmp;
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		/* Don't want a node to appear more than once */
		if (node_isset(n, *used_node_mask))
			continue;

		/* Use the distance array to find the distance */
		val = node_distance(node, n);

1686 1687 1688
		/* Penalize nodes under us ("prefer the next node") */
		val += (n < node);

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1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709
		/* Give preference to headless and unused nodes */
		tmp = node_to_cpumask(n);
		if (!cpus_empty(tmp))
			val += PENALTY_FOR_NODE_WITH_CPUS;

		/* Slight preference for less loaded node */
		val *= (MAX_NODE_LOAD*MAX_NUMNODES);
		val += node_load[n];

		if (val < min_val) {
			min_val = val;
			best_node = n;
		}
	}

	if (best_node >= 0)
		node_set(best_node, *used_node_mask);

	return best_node;
}

1710
static void __meminit build_zonelists(pg_data_t *pgdat)
L
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1711
{
1712 1713
	int j, node, local_node;
	enum zone_type i;
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1714 1715 1716 1717 1718
	int prev_node, load;
	struct zonelist *zonelist;
	nodemask_t used_mask;

	/* initialize zonelists */
1719
	for (i = 0; i < MAX_NR_ZONES; i++) {
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1720 1721 1722 1723 1724 1725 1726 1727 1728 1729
		zonelist = pgdat->node_zonelists + i;
		zonelist->zones[0] = NULL;
	}

	/* NUMA-aware ordering of nodes */
	local_node = pgdat->node_id;
	load = num_online_nodes();
	prev_node = local_node;
	nodes_clear(used_mask);
	while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
1730 1731 1732 1733 1734 1735 1736 1737 1738
		int distance = node_distance(local_node, node);

		/*
		 * If another node is sufficiently far away then it is better
		 * to reclaim pages in a zone before going off node.
		 */
		if (distance > RECLAIM_DISTANCE)
			zone_reclaim_mode = 1;

L
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1739 1740 1741 1742 1743
		/*
		 * We don't want to pressure a particular node.
		 * So adding penalty to the first node in same
		 * distance group to make it round-robin.
		 */
1744 1745

		if (distance != node_distance(local_node, prev_node))
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1746 1747 1748
			node_load[node] += load;
		prev_node = node;
		load--;
1749
		for (i = 0; i < MAX_NR_ZONES; i++) {
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1750 1751 1752
			zonelist = pgdat->node_zonelists + i;
			for (j = 0; zonelist->zones[j] != NULL; j++);

1753
	 		j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
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			zonelist->zones[j] = NULL;
		}
	}
}

1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776
/* Construct the zonelist performance cache - see further mmzone.h */
static void __meminit build_zonelist_cache(pg_data_t *pgdat)
{
	int i;

	for (i = 0; i < MAX_NR_ZONES; i++) {
		struct zonelist *zonelist;
		struct zonelist_cache *zlc;
		struct zone **z;

		zonelist = pgdat->node_zonelists + i;
		zonelist->zlcache_ptr = zlc = &zonelist->zlcache;
		bitmap_zero(zlc->fullzones, MAX_ZONES_PER_ZONELIST);
		for (z = zonelist->zones; *z; z++)
			zlc->z_to_n[z - zonelist->zones] = zone_to_nid(*z);
	}
}

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#else	/* CONFIG_NUMA */

1779
static void __meminit build_zonelists(pg_data_t *pgdat)
L
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1780
{
1781 1782
	int node, local_node;
	enum zone_type i,j;
L
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1783 1784

	local_node = pgdat->node_id;
1785
	for (i = 0; i < MAX_NR_ZONES; i++) {
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		struct zonelist *zonelist;

		zonelist = pgdat->node_zonelists + i;

1790
 		j = build_zonelists_node(pgdat, zonelist, 0, i);
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 		/*
 		 * Now we build the zonelist so that it contains the zones
 		 * of all the other nodes.
 		 * We don't want to pressure a particular node, so when
 		 * building the zones for node N, we make sure that the
 		 * zones coming right after the local ones are those from
 		 * node N+1 (modulo N)
 		 */
		for (node = local_node + 1; node < MAX_NUMNODES; node++) {
			if (!node_online(node))
				continue;
1802
			j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
L
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1803 1804 1805 1806
		}
		for (node = 0; node < local_node; node++) {
			if (!node_online(node))
				continue;
1807
			j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
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1808 1809 1810 1811 1812 1813
		}

		zonelist->zones[j] = NULL;
	}
}

1814 1815 1816 1817 1818 1819 1820 1821 1822
/* non-NUMA variant of zonelist performance cache - just NULL zlcache_ptr */
static void __meminit build_zonelist_cache(pg_data_t *pgdat)
{
	int i;

	for (i = 0; i < MAX_NR_ZONES; i++)
		pgdat->node_zonelists[i].zlcache_ptr = NULL;
}

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1823 1824
#endif	/* CONFIG_NUMA */

1825 1826
/* return values int ....just for stop_machine_run() */
static int __meminit __build_all_zonelists(void *dummy)
L
Linus Torvalds 已提交
1827
{
1828
	int nid;
1829 1830

	for_each_online_node(nid) {
1831
		build_zonelists(NODE_DATA(nid));
1832 1833
		build_zonelist_cache(NODE_DATA(nid));
	}
1834 1835 1836 1837 1838 1839
	return 0;
}

void __meminit build_all_zonelists(void)
{
	if (system_state == SYSTEM_BOOTING) {
1840
		__build_all_zonelists(NULL);
1841 1842 1843 1844 1845 1846 1847
		cpuset_init_current_mems_allowed();
	} else {
		/* we have to stop all cpus to guaranntee there is no user
		   of zonelist */
		stop_machine_run(__build_all_zonelists, NULL, NR_CPUS);
		/* cpuset refresh routine should be here */
	}
1848 1849 1850
	vm_total_pages = nr_free_pagecache_pages();
	printk("Built %i zonelists.  Total pages: %ld\n",
			num_online_nodes(), vm_total_pages);
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Linus Torvalds 已提交
1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865
}

/*
 * 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

1866
#ifndef CONFIG_MEMORY_HOTPLUG
1867
static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
L
Linus Torvalds 已提交
1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884
{
	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 max(size, 4UL);
}
1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907
#else
/*
 * A zone's size might be changed by hot-add, so it is not possible to determine
 * a suitable size for its wait_table.  So we use the maximum size now.
 *
 * The max wait table size = 4096 x sizeof(wait_queue_head_t).   ie:
 *
 *    i386 (preemption config)    : 4096 x 16 = 64Kbyte.
 *    ia64, x86-64 (no preemption): 4096 x 20 = 80Kbyte.
 *    ia64, x86-64 (preemption)   : 4096 x 24 = 96Kbyte.
 *
 * The maximum entries are prepared when a zone's memory is (512K + 256) pages
 * or more by the traditional way. (See above).  It equals:
 *
 *    i386, x86-64, powerpc(4K page size) : =  ( 2G + 1M)byte.
 *    ia64(16K page size)                 : =  ( 8G + 4M)byte.
 *    powerpc (64K page size)             : =  (32G +16M)byte.
 */
static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
{
	return 4096UL;
}
#endif
L
Linus Torvalds 已提交
1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925

/*
 * 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))

/*
 * 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.
 */
1926
void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
D
Dave Hansen 已提交
1927
		unsigned long start_pfn, enum memmap_context context)
L
Linus Torvalds 已提交
1928 1929
{
	struct page *page;
A
Andy Whitcroft 已提交
1930 1931
	unsigned long end_pfn = start_pfn + size;
	unsigned long pfn;
L
Linus Torvalds 已提交
1932

1933
	for (pfn = start_pfn; pfn < end_pfn; pfn++) {
D
Dave Hansen 已提交
1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944
		/*
		 * There can be holes in boot-time mem_map[]s
		 * handed to this function.  They do not
		 * exist on hotplugged memory.
		 */
		if (context == MEMMAP_EARLY) {
			if (!early_pfn_valid(pfn))
				continue;
			if (!early_pfn_in_nid(pfn, nid))
				continue;
		}
A
Andy Whitcroft 已提交
1945 1946
		page = pfn_to_page(pfn);
		set_page_links(page, zone, nid, pfn);
1947
		init_page_count(page);
L
Linus Torvalds 已提交
1948 1949 1950 1951 1952 1953
		reset_page_mapcount(page);
		SetPageReserved(page);
		INIT_LIST_HEAD(&page->lru);
#ifdef WANT_PAGE_VIRTUAL
		/* The shift won't overflow because ZONE_NORMAL is below 4G. */
		if (!is_highmem_idx(zone))
1954
			set_page_address(page, __va(pfn << PAGE_SHIFT));
L
Linus Torvalds 已提交
1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970
#endif
	}
}

void zone_init_free_lists(struct pglist_data *pgdat, struct zone *zone,
				unsigned long size)
{
	int order;
	for (order = 0; order < MAX_ORDER ; order++) {
		INIT_LIST_HEAD(&zone->free_area[order].free_list);
		zone->free_area[order].nr_free = 0;
	}
}

#ifndef __HAVE_ARCH_MEMMAP_INIT
#define memmap_init(size, nid, zone, start_pfn) \
D
Dave Hansen 已提交
1971
	memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
L
Linus Torvalds 已提交
1972 1973
#endif

1974
static int __cpuinit zone_batchsize(struct zone *zone)
1975 1976 1977 1978 1979
{
	int batch;

	/*
	 * The per-cpu-pages pools are set to around 1000th of the
1980
	 * size of the zone.  But no more than 1/2 of a meg.
1981 1982 1983 1984
	 *
	 * OK, so we don't know how big the cache is.  So guess.
	 */
	batch = zone->present_pages / 1024;
1985 1986
	if (batch * PAGE_SIZE > 512 * 1024)
		batch = (512 * 1024) / PAGE_SIZE;
1987 1988 1989 1990 1991
	batch /= 4;		/* We effectively *= 4 below */
	if (batch < 1)
		batch = 1;

	/*
1992 1993 1994
	 * Clamp the batch to a 2^n - 1 value. Having a power
	 * of 2 value was found to be more likely to have
	 * suboptimal cache aliasing properties in some cases.
1995
	 *
1996 1997 1998 1999
	 * For example if 2 tasks are alternately allocating
	 * batches of pages, one task can end up with a lot
	 * of pages of one half of the possible page colors
	 * and the other with pages of the other colors.
2000
	 */
2001
	batch = (1 << (fls(batch + batch/2)-1)) - 1;
2002

2003 2004 2005
	return batch;
}

2006 2007 2008 2009
inline void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
{
	struct per_cpu_pages *pcp;

2010 2011
	memset(p, 0, sizeof(*p));

2012 2013 2014 2015 2016 2017 2018 2019 2020
	pcp = &p->pcp[0];		/* hot */
	pcp->count = 0;
	pcp->high = 6 * batch;
	pcp->batch = max(1UL, 1 * batch);
	INIT_LIST_HEAD(&pcp->list);

	pcp = &p->pcp[1];		/* cold*/
	pcp->count = 0;
	pcp->high = 2 * batch;
2021
	pcp->batch = max(1UL, batch/2);
2022 2023 2024
	INIT_LIST_HEAD(&pcp->list);
}

2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042
/*
 * setup_pagelist_highmark() sets the high water mark for hot per_cpu_pagelist
 * to the value high for the pageset p.
 */

static void setup_pagelist_highmark(struct per_cpu_pageset *p,
				unsigned long high)
{
	struct per_cpu_pages *pcp;

	pcp = &p->pcp[0]; /* hot list */
	pcp->high = high;
	pcp->batch = max(1UL, high/4);
	if ((high/4) > (PAGE_SHIFT * 8))
		pcp->batch = PAGE_SHIFT * 8;
}


2043 2044
#ifdef CONFIG_NUMA
/*
2045 2046 2047 2048 2049 2050 2051
 * Boot pageset table. One per cpu which is going to be used for all
 * zones and all nodes. The parameters will be set in such a way
 * that an item put on a list will immediately be handed over to
 * the buddy list. This is safe since pageset manipulation is done
 * with interrupts disabled.
 *
 * Some NUMA counter updates may also be caught by the boot pagesets.
2052 2053 2054 2055 2056 2057 2058 2059
 *
 * The boot_pagesets must be kept even after bootup is complete for
 * unused processors and/or zones. They do play a role for bootstrapping
 * hotplugged processors.
 *
 * zoneinfo_show() and maybe other functions do
 * not check if the processor is online before following the pageset pointer.
 * Other parts of the kernel may not check if the zone is available.
2060
 */
2061
static struct per_cpu_pageset boot_pageset[NR_CPUS];
2062 2063 2064

/*
 * Dynamically allocate memory for the
2065 2066
 * per cpu pageset array in struct zone.
 */
2067
static int __cpuinit process_zones(int cpu)
2068 2069 2070 2071 2072
{
	struct zone *zone, *dzone;

	for_each_zone(zone) {

2073 2074 2075
		if (!populated_zone(zone))
			continue;

N
Nick Piggin 已提交
2076
		zone_pcp(zone, cpu) = kmalloc_node(sizeof(struct per_cpu_pageset),
2077
					 GFP_KERNEL, cpu_to_node(cpu));
N
Nick Piggin 已提交
2078
		if (!zone_pcp(zone, cpu))
2079 2080
			goto bad;

N
Nick Piggin 已提交
2081
		setup_pageset(zone_pcp(zone, cpu), zone_batchsize(zone));
2082 2083 2084 2085

		if (percpu_pagelist_fraction)
			setup_pagelist_highmark(zone_pcp(zone, cpu),
			 	(zone->present_pages / percpu_pagelist_fraction));
2086 2087 2088 2089 2090 2091 2092
	}

	return 0;
bad:
	for_each_zone(dzone) {
		if (dzone == zone)
			break;
N
Nick Piggin 已提交
2093 2094
		kfree(zone_pcp(dzone, cpu));
		zone_pcp(dzone, cpu) = NULL;
2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105
	}
	return -ENOMEM;
}

static inline void free_zone_pagesets(int cpu)
{
	struct zone *zone;

	for_each_zone(zone) {
		struct per_cpu_pageset *pset = zone_pcp(zone, cpu);

2106 2107 2108
		/* Free per_cpu_pageset if it is slab allocated */
		if (pset != &boot_pageset[cpu])
			kfree(pset);
2109 2110 2111 2112
		zone_pcp(zone, cpu) = NULL;
	}
}

2113
static int __cpuinit pageset_cpuup_callback(struct notifier_block *nfb,
2114 2115 2116 2117 2118 2119 2120
		unsigned long action,
		void *hcpu)
{
	int cpu = (long)hcpu;
	int ret = NOTIFY_OK;

	switch (action) {
2121 2122 2123 2124 2125 2126 2127 2128 2129 2130
	case CPU_UP_PREPARE:
		if (process_zones(cpu))
			ret = NOTIFY_BAD;
		break;
	case CPU_UP_CANCELED:
	case CPU_DEAD:
		free_zone_pagesets(cpu);
		break;
	default:
		break;
2131 2132 2133 2134
	}
	return ret;
}

2135
static struct notifier_block __cpuinitdata pageset_notifier =
2136 2137
	{ &pageset_cpuup_callback, NULL, 0 };

2138
void __init setup_per_cpu_pageset(void)
2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152
{
	int err;

	/* Initialize per_cpu_pageset for cpu 0.
	 * A cpuup callback will do this for every cpu
	 * as it comes online
	 */
	err = process_zones(smp_processor_id());
	BUG_ON(err);
	register_cpu_notifier(&pageset_notifier);
}

#endif

2153
static __meminit
2154
int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
2155 2156 2157
{
	int i;
	struct pglist_data *pgdat = zone->zone_pgdat;
2158
	size_t alloc_size;
2159 2160 2161 2162 2163

	/*
	 * The per-page waitqueue mechanism uses hashed waitqueues
	 * per zone.
	 */
2164 2165 2166 2167
	zone->wait_table_hash_nr_entries =
		 wait_table_hash_nr_entries(zone_size_pages);
	zone->wait_table_bits =
		wait_table_bits(zone->wait_table_hash_nr_entries);
2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188
	alloc_size = zone->wait_table_hash_nr_entries
					* sizeof(wait_queue_head_t);

 	if (system_state == SYSTEM_BOOTING) {
		zone->wait_table = (wait_queue_head_t *)
			alloc_bootmem_node(pgdat, alloc_size);
	} else {
		/*
		 * This case means that a zone whose size was 0 gets new memory
		 * via memory hot-add.
		 * But it may be the case that a new node was hot-added.  In
		 * this case vmalloc() will not be able to use this new node's
		 * memory - this wait_table must be initialized to use this new
		 * node itself as well.
		 * To use this new node's memory, further consideration will be
		 * necessary.
		 */
		zone->wait_table = (wait_queue_head_t *)vmalloc(alloc_size);
	}
	if (!zone->wait_table)
		return -ENOMEM;
2189

2190
	for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
2191
		init_waitqueue_head(zone->wait_table + i);
2192 2193

	return 0;
2194 2195
}

2196
static __meminit void zone_pcp_init(struct zone *zone)
2197 2198 2199 2200 2201 2202 2203
{
	int cpu;
	unsigned long batch = zone_batchsize(zone);

	for (cpu = 0; cpu < NR_CPUS; cpu++) {
#ifdef CONFIG_NUMA
		/* Early boot. Slab allocator not functional yet */
N
Nick Piggin 已提交
2204
		zone_pcp(zone, cpu) = &boot_pageset[cpu];
2205 2206 2207 2208 2209
		setup_pageset(&boot_pageset[cpu],0);
#else
		setup_pageset(zone_pcp(zone,cpu), batch);
#endif
	}
A
Anton Blanchard 已提交
2210 2211 2212
	if (zone->present_pages)
		printk(KERN_DEBUG "  %s zone: %lu pages, LIFO batch:%lu\n",
			zone->name, zone->present_pages, batch);
2213 2214
}

2215 2216
__meminit int init_currently_empty_zone(struct zone *zone,
					unsigned long zone_start_pfn,
D
Dave Hansen 已提交
2217 2218
					unsigned long size,
					enum memmap_context context)
2219 2220
{
	struct pglist_data *pgdat = zone->zone_pgdat;
2221 2222 2223 2224
	int ret;
	ret = zone_wait_table_init(zone, size);
	if (ret)
		return ret;
2225 2226 2227 2228 2229 2230 2231
	pgdat->nr_zones = zone_idx(zone) + 1;

	zone->zone_start_pfn = zone_start_pfn;

	memmap_init(size, pgdat->node_id, zone_idx(zone), zone_start_pfn);

	zone_init_free_lists(pgdat, zone, zone->spanned_pages);
2232 2233

	return 0;
2234 2235
}

2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294
#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
/*
 * Basic iterator support. Return the first range of PFNs for a node
 * Note: nid == MAX_NUMNODES returns first region regardless of node
 */
static int __init first_active_region_index_in_nid(int nid)
{
	int i;

	for (i = 0; i < nr_nodemap_entries; i++)
		if (nid == MAX_NUMNODES || early_node_map[i].nid == nid)
			return i;

	return -1;
}

/*
 * Basic iterator support. Return the next active range of PFNs for a node
 * Note: nid == MAX_NUMNODES returns next region regardles of node
 */
static int __init next_active_region_index_in_nid(int index, int nid)
{
	for (index = index + 1; index < nr_nodemap_entries; index++)
		if (nid == MAX_NUMNODES || early_node_map[index].nid == nid)
			return index;

	return -1;
}

#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
/*
 * Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
 * Architectures may implement their own version but if add_active_range()
 * was used and there are no special requirements, this is a convenient
 * alternative
 */
int __init early_pfn_to_nid(unsigned long pfn)
{
	int i;

	for (i = 0; i < nr_nodemap_entries; i++) {
		unsigned long start_pfn = early_node_map[i].start_pfn;
		unsigned long end_pfn = early_node_map[i].end_pfn;

		if (start_pfn <= pfn && pfn < end_pfn)
			return early_node_map[i].nid;
	}

	return 0;
}
#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */

/* Basic iterator support to walk early_node_map[] */
#define for_each_active_range_index_in_nid(i, nid) \
	for (i = first_active_region_index_in_nid(nid); i != -1; \
				i = next_active_region_index_in_nid(i, nid))

/**
 * free_bootmem_with_active_regions - Call free_bootmem_node for each active range
2295 2296
 * @nid: The node to free memory on. If MAX_NUMNODES, all nodes are freed.
 * @max_low_pfn: The highest PFN that will be passed to free_bootmem_node
2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325
 *
 * If an architecture guarantees that all ranges registered with
 * add_active_ranges() contain no holes and may be freed, this
 * this function may be used instead of calling free_bootmem() manually.
 */
void __init free_bootmem_with_active_regions(int nid,
						unsigned long max_low_pfn)
{
	int i;

	for_each_active_range_index_in_nid(i, nid) {
		unsigned long size_pages = 0;
		unsigned long end_pfn = early_node_map[i].end_pfn;

		if (early_node_map[i].start_pfn >= max_low_pfn)
			continue;

		if (end_pfn > max_low_pfn)
			end_pfn = max_low_pfn;

		size_pages = end_pfn - early_node_map[i].start_pfn;
		free_bootmem_node(NODE_DATA(early_node_map[i].nid),
				PFN_PHYS(early_node_map[i].start_pfn),
				size_pages << PAGE_SHIFT);
	}
}

/**
 * sparse_memory_present_with_active_regions - Call memory_present for each active range
2326
 * @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
2327 2328 2329
 *
 * If an architecture guarantees that all ranges registered with
 * add_active_ranges() contain no holes and may be freed, this
2330
 * function may be used instead of calling memory_present() manually.
2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341
 */
void __init sparse_memory_present_with_active_regions(int nid)
{
	int i;

	for_each_active_range_index_in_nid(i, nid)
		memory_present(early_node_map[i].nid,
				early_node_map[i].start_pfn,
				early_node_map[i].end_pfn);
}

2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397
/**
 * push_node_boundaries - Push node boundaries to at least the requested boundary
 * @nid: The nid of the node to push the boundary for
 * @start_pfn: The start pfn of the node
 * @end_pfn: The end pfn of the node
 *
 * In reserve-based hot-add, mem_map is allocated that is unused until hotadd
 * time. Specifically, on x86_64, SRAT will report ranges that can potentially
 * be hotplugged even though no physical memory exists. This function allows
 * an arch to push out the node boundaries so mem_map is allocated that can
 * be used later.
 */
#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
void __init push_node_boundaries(unsigned int nid,
		unsigned long start_pfn, unsigned long end_pfn)
{
	printk(KERN_DEBUG "Entering push_node_boundaries(%u, %lu, %lu)\n",
			nid, start_pfn, end_pfn);

	/* Initialise the boundary for this node if necessary */
	if (node_boundary_end_pfn[nid] == 0)
		node_boundary_start_pfn[nid] = -1UL;

	/* Update the boundaries */
	if (node_boundary_start_pfn[nid] > start_pfn)
		node_boundary_start_pfn[nid] = start_pfn;
	if (node_boundary_end_pfn[nid] < end_pfn)
		node_boundary_end_pfn[nid] = end_pfn;
}

/* If necessary, push the node boundary out for reserve hotadd */
static void __init account_node_boundary(unsigned int nid,
		unsigned long *start_pfn, unsigned long *end_pfn)
{
	printk(KERN_DEBUG "Entering account_node_boundary(%u, %lu, %lu)\n",
			nid, *start_pfn, *end_pfn);

	/* Return if boundary information has not been provided */
	if (node_boundary_end_pfn[nid] == 0)
		return;

	/* Check the boundaries and update if necessary */
	if (node_boundary_start_pfn[nid] < *start_pfn)
		*start_pfn = node_boundary_start_pfn[nid];
	if (node_boundary_end_pfn[nid] > *end_pfn)
		*end_pfn = node_boundary_end_pfn[nid];
}
#else
void __init push_node_boundaries(unsigned int nid,
		unsigned long start_pfn, unsigned long end_pfn) {}

static void __init account_node_boundary(unsigned int nid,
		unsigned long *start_pfn, unsigned long *end_pfn) {}
#endif


2398 2399
/**
 * get_pfn_range_for_nid - Return the start and end page frames for a node
2400 2401 2402
 * @nid: The nid to return the range for. If MAX_NUMNODES, the min and max PFN are returned.
 * @start_pfn: Passed by reference. On return, it will have the node start_pfn.
 * @end_pfn: Passed by reference. On return, it will have the node end_pfn.
2403 2404 2405 2406
 *
 * It returns the start and end page frame of a node based on information
 * provided by an arch calling add_active_range(). If called for a node
 * with no available memory, a warning is printed and the start and end
2407
 * PFNs will be 0.
2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424
 */
void __init get_pfn_range_for_nid(unsigned int nid,
			unsigned long *start_pfn, unsigned long *end_pfn)
{
	int i;
	*start_pfn = -1UL;
	*end_pfn = 0;

	for_each_active_range_index_in_nid(i, nid) {
		*start_pfn = min(*start_pfn, early_node_map[i].start_pfn);
		*end_pfn = max(*end_pfn, early_node_map[i].end_pfn);
	}

	if (*start_pfn == -1UL) {
		printk(KERN_WARNING "Node %u active with no memory\n", nid);
		*start_pfn = 0;
	}
2425 2426 2427

	/* Push the node boundaries out if requested */
	account_node_boundary(nid, start_pfn, end_pfn);
2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459
}

/*
 * Return the number of pages a zone spans in a node, including holes
 * present_pages = zone_spanned_pages_in_node() - zone_absent_pages_in_node()
 */
unsigned long __init zone_spanned_pages_in_node(int nid,
					unsigned long zone_type,
					unsigned long *ignored)
{
	unsigned long node_start_pfn, node_end_pfn;
	unsigned long zone_start_pfn, zone_end_pfn;

	/* Get the start and end of the node and zone */
	get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
	zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
	zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];

	/* Check that this node has pages within the zone's required range */
	if (zone_end_pfn < node_start_pfn || zone_start_pfn > node_end_pfn)
		return 0;

	/* Move the zone boundaries inside the node if necessary */
	zone_end_pfn = min(zone_end_pfn, node_end_pfn);
	zone_start_pfn = max(zone_start_pfn, node_start_pfn);

	/* Return the spanned pages */
	return zone_end_pfn - zone_start_pfn;
}

/*
 * Return the number of holes in a range on a node. If nid is MAX_NUMNODES,
2460
 * then all holes in the requested range will be accounted for.
2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474
 */
unsigned long __init __absent_pages_in_range(int nid,
				unsigned long range_start_pfn,
				unsigned long range_end_pfn)
{
	int i = 0;
	unsigned long prev_end_pfn = 0, hole_pages = 0;
	unsigned long start_pfn;

	/* Find the end_pfn of the first active range of pfns in the node */
	i = first_active_region_index_in_nid(nid);
	if (i == -1)
		return 0;

2475 2476 2477 2478
	/* Account for ranges before physical memory on this node */
	if (early_node_map[i].start_pfn > range_start_pfn)
		hole_pages = early_node_map[i].start_pfn - range_start_pfn;

2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499
	prev_end_pfn = early_node_map[i].start_pfn;

	/* Find all holes for the zone within the node */
	for (; i != -1; i = next_active_region_index_in_nid(i, nid)) {

		/* No need to continue if prev_end_pfn is outside the zone */
		if (prev_end_pfn >= range_end_pfn)
			break;

		/* Make sure the end of the zone is not within the hole */
		start_pfn = min(early_node_map[i].start_pfn, range_end_pfn);
		prev_end_pfn = max(prev_end_pfn, range_start_pfn);

		/* Update the hole size cound and move on */
		if (start_pfn > range_start_pfn) {
			BUG_ON(prev_end_pfn > start_pfn);
			hole_pages += start_pfn - prev_end_pfn;
		}
		prev_end_pfn = early_node_map[i].end_pfn;
	}

2500 2501
	/* Account for ranges past physical memory on this node */
	if (range_end_pfn > prev_end_pfn)
2502
		hole_pages += range_end_pfn -
2503 2504
				max(range_start_pfn, prev_end_pfn);

2505 2506 2507 2508 2509 2510 2511 2512
	return hole_pages;
}

/**
 * absent_pages_in_range - Return number of page frames in holes within a range
 * @start_pfn: The start PFN to start searching for holes
 * @end_pfn: The end PFN to stop searching for holes
 *
2513
 * It returns the number of pages frames in memory holes within a range.
2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525
 */
unsigned long __init absent_pages_in_range(unsigned long start_pfn,
							unsigned long end_pfn)
{
	return __absent_pages_in_range(MAX_NUMNODES, start_pfn, end_pfn);
}

/* Return the number of page frames in holes in a zone on a node */
unsigned long __init zone_absent_pages_in_node(int nid,
					unsigned long zone_type,
					unsigned long *ignored)
{
2526 2527 2528 2529 2530 2531 2532 2533 2534 2535
	unsigned long node_start_pfn, node_end_pfn;
	unsigned long zone_start_pfn, zone_end_pfn;

	get_pfn_range_for_nid(nid, &node_start_pfn, &node_end_pfn);
	zone_start_pfn = max(arch_zone_lowest_possible_pfn[zone_type],
							node_start_pfn);
	zone_end_pfn = min(arch_zone_highest_possible_pfn[zone_type],
							node_end_pfn);

	return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
2536
}
2537

2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554
#else
static inline unsigned long zone_spanned_pages_in_node(int nid,
					unsigned long zone_type,
					unsigned long *zones_size)
{
	return zones_size[zone_type];
}

static inline unsigned long zone_absent_pages_in_node(int nid,
						unsigned long zone_type,
						unsigned long *zholes_size)
{
	if (!zholes_size)
		return 0;

	return zholes_size[zone_type];
}
2555

2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578
#endif

static void __init calculate_node_totalpages(struct pglist_data *pgdat,
		unsigned long *zones_size, unsigned long *zholes_size)
{
	unsigned long realtotalpages, totalpages = 0;
	enum zone_type i;

	for (i = 0; i < MAX_NR_ZONES; i++)
		totalpages += zone_spanned_pages_in_node(pgdat->node_id, i,
								zones_size);
	pgdat->node_spanned_pages = totalpages;

	realtotalpages = totalpages;
	for (i = 0; i < MAX_NR_ZONES; i++)
		realtotalpages -=
			zone_absent_pages_in_node(pgdat->node_id, i,
								zholes_size);
	pgdat->node_present_pages = realtotalpages;
	printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
							realtotalpages);
}

L
Linus Torvalds 已提交
2579 2580 2581 2582 2583 2584
/*
 * Set up the zone data structures:
 *   - mark all pages reserved
 *   - mark all memory queues empty
 *   - clear the memory bitmaps
 */
2585
static void __meminit free_area_init_core(struct pglist_data *pgdat,
L
Linus Torvalds 已提交
2586 2587
		unsigned long *zones_size, unsigned long *zholes_size)
{
2588
	enum zone_type j;
2589
	int nid = pgdat->node_id;
L
Linus Torvalds 已提交
2590
	unsigned long zone_start_pfn = pgdat->node_start_pfn;
2591
	int ret;
L
Linus Torvalds 已提交
2592

2593
	pgdat_resize_init(pgdat);
L
Linus Torvalds 已提交
2594 2595 2596 2597 2598 2599
	pgdat->nr_zones = 0;
	init_waitqueue_head(&pgdat->kswapd_wait);
	pgdat->kswapd_max_order = 0;
	
	for (j = 0; j < MAX_NR_ZONES; j++) {
		struct zone *zone = pgdat->node_zones + j;
2600
		unsigned long size, realsize, memmap_pages;
L
Linus Torvalds 已提交
2601

2602 2603 2604
		size = zone_spanned_pages_in_node(nid, j, zones_size);
		realsize = size - zone_absent_pages_in_node(nid, j,
								zholes_size);
L
Linus Torvalds 已提交
2605

2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621
		/*
		 * Adjust realsize so that it accounts for how much memory
		 * is used by this zone for memmap. This affects the watermark
		 * and per-cpu initialisations
		 */
		memmap_pages = (size * sizeof(struct page)) >> PAGE_SHIFT;
		if (realsize >= memmap_pages) {
			realsize -= memmap_pages;
			printk(KERN_DEBUG
				"  %s zone: %lu pages used for memmap\n",
				zone_names[j], memmap_pages);
		} else
			printk(KERN_WARNING
				"  %s zone: %lu pages exceeds realsize %lu\n",
				zone_names[j], memmap_pages, realsize);

2622 2623
		/* Account for reserved pages */
		if (j == 0 && realsize > dma_reserve) {
2624
			realsize -= dma_reserve;
2625 2626
			printk(KERN_DEBUG "  %s zone: %lu pages reserved\n",
					zone_names[0], dma_reserve);
2627 2628
		}

2629
		if (!is_highmem_idx(j))
L
Linus Torvalds 已提交
2630 2631 2632 2633 2634
			nr_kernel_pages += realsize;
		nr_all_pages += realsize;

		zone->spanned_pages = size;
		zone->present_pages = realsize;
2635
#ifdef CONFIG_NUMA
2636
		zone->node = nid;
2637
		zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
2638
						/ 100;
2639
		zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
2640
#endif
L
Linus Torvalds 已提交
2641 2642 2643
		zone->name = zone_names[j];
		spin_lock_init(&zone->lock);
		spin_lock_init(&zone->lru_lock);
2644
		zone_seqlock_init(zone);
L
Linus Torvalds 已提交
2645 2646
		zone->zone_pgdat = pgdat;

2647
		zone->prev_priority = DEF_PRIORITY;
L
Linus Torvalds 已提交
2648

2649
		zone_pcp_init(zone);
L
Linus Torvalds 已提交
2650 2651 2652 2653
		INIT_LIST_HEAD(&zone->active_list);
		INIT_LIST_HEAD(&zone->inactive_list);
		zone->nr_scan_active = 0;
		zone->nr_scan_inactive = 0;
2654
		zap_zone_vm_stats(zone);
2655
		atomic_set(&zone->reclaim_in_progress, 0);
L
Linus Torvalds 已提交
2656 2657 2658
		if (!size)
			continue;

D
Dave Hansen 已提交
2659 2660
		ret = init_currently_empty_zone(zone, zone_start_pfn,
						size, MEMMAP_EARLY);
2661
		BUG_ON(ret);
L
Linus Torvalds 已提交
2662 2663 2664 2665 2666 2667 2668 2669 2670 2671
		zone_start_pfn += size;
	}
}

static void __init alloc_node_mem_map(struct pglist_data *pgdat)
{
	/* Skip empty nodes */
	if (!pgdat->node_spanned_pages)
		return;

A
Andy Whitcroft 已提交
2672
#ifdef CONFIG_FLAT_NODE_MEM_MAP
L
Linus Torvalds 已提交
2673 2674
	/* ia64 gets its own node_mem_map, before this, without bootmem */
	if (!pgdat->node_mem_map) {
2675
		unsigned long size, start, end;
A
Andy Whitcroft 已提交
2676 2677
		struct page *map;

2678 2679 2680 2681 2682 2683 2684 2685 2686
		/*
		 * The zone's endpoints aren't required to be MAX_ORDER
		 * aligned but the node_mem_map endpoints must be in order
		 * for the buddy allocator to function correctly.
		 */
		start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
		end = pgdat->node_start_pfn + pgdat->node_spanned_pages;
		end = ALIGN(end, MAX_ORDER_NR_PAGES);
		size =  (end - start) * sizeof(struct page);
2687 2688 2689
		map = alloc_remap(pgdat->node_id, size);
		if (!map)
			map = alloc_bootmem_node(pgdat, size);
2690
		pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
L
Linus Torvalds 已提交
2691
	}
A
Andy Whitcroft 已提交
2692
#ifdef CONFIG_FLATMEM
L
Linus Torvalds 已提交
2693 2694 2695
	/*
	 * With no DISCONTIG, the global mem_map is just set as node 0's
	 */
2696
	if (pgdat == NODE_DATA(0)) {
L
Linus Torvalds 已提交
2697
		mem_map = NODE_DATA(0)->node_mem_map;
2698 2699 2700 2701 2702
#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
		if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
			mem_map -= pgdat->node_start_pfn;
#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
	}
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#endif
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#endif /* CONFIG_FLAT_NODE_MEM_MAP */
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}

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void __meminit free_area_init_node(int nid, struct pglist_data *pgdat,
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		unsigned long *zones_size, unsigned long node_start_pfn,
		unsigned long *zholes_size)
{
	pgdat->node_id = nid;
	pgdat->node_start_pfn = node_start_pfn;
2713
	calculate_node_totalpages(pgdat, zones_size, zholes_size);
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	alloc_node_mem_map(pgdat);

	free_area_init_core(pgdat, zones_size, zholes_size);
}

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#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
/**
 * add_active_range - Register a range of PFNs backed by physical memory
 * @nid: The node ID the range resides on
 * @start_pfn: The start PFN of the available physical memory
 * @end_pfn: The end PFN of the available physical memory
 *
 * These ranges are stored in an early_node_map[] and later used by
 * free_area_init_nodes() to calculate zone sizes and holes. If the
 * range spans a memory hole, it is up to the architecture to ensure
 * the memory is not freed by the bootmem allocator. If possible
 * the range being registered will be merged with existing ranges.
 */
void __init add_active_range(unsigned int nid, unsigned long start_pfn,
						unsigned long end_pfn)
{
	int i;

	printk(KERN_DEBUG "Entering add_active_range(%d, %lu, %lu) "
			  "%d entries of %d used\n",
			  nid, start_pfn, end_pfn,
			  nr_nodemap_entries, MAX_ACTIVE_REGIONS);

	/* Merge with existing active regions if possible */
	for (i = 0; i < nr_nodemap_entries; i++) {
		if (early_node_map[i].nid != nid)
			continue;

		/* Skip if an existing region covers this new one */
		if (start_pfn >= early_node_map[i].start_pfn &&
				end_pfn <= early_node_map[i].end_pfn)
			return;

		/* Merge forward if suitable */
		if (start_pfn <= early_node_map[i].end_pfn &&
				end_pfn > early_node_map[i].end_pfn) {
			early_node_map[i].end_pfn = end_pfn;
			return;
		}

		/* Merge backward if suitable */
		if (start_pfn < early_node_map[i].end_pfn &&
				end_pfn >= early_node_map[i].start_pfn) {
			early_node_map[i].start_pfn = start_pfn;
			return;
		}
	}

	/* Check that early_node_map is large enough */
	if (i >= MAX_ACTIVE_REGIONS) {
		printk(KERN_CRIT "More than %d memory regions, truncating\n",
							MAX_ACTIVE_REGIONS);
		return;
	}

	early_node_map[i].nid = nid;
	early_node_map[i].start_pfn = start_pfn;
	early_node_map[i].end_pfn = end_pfn;
	nr_nodemap_entries = i + 1;
}

/**
 * shrink_active_range - Shrink an existing registered range of PFNs
 * @nid: The node id the range is on that should be shrunk
 * @old_end_pfn: The old end PFN of the range
 * @new_end_pfn: The new PFN of the range
 *
 * i386 with NUMA use alloc_remap() to store a node_mem_map on a local node.
 * The map is kept at the end physical page range that has already been
 * registered with add_active_range(). This function allows an arch to shrink
 * an existing registered range.
 */
void __init shrink_active_range(unsigned int nid, unsigned long old_end_pfn,
						unsigned long new_end_pfn)
{
	int i;

	/* Find the old active region end and shrink */
	for_each_active_range_index_in_nid(i, nid)
		if (early_node_map[i].end_pfn == old_end_pfn) {
			early_node_map[i].end_pfn = new_end_pfn;
			break;
		}
}

/**
 * remove_all_active_ranges - Remove all currently registered regions
2807
 *
2808 2809 2810 2811
 * During discovery, it may be found that a table like SRAT is invalid
 * and an alternative discovery method must be used. This function removes
 * all currently registered regions.
 */
2812
void __init remove_all_active_ranges(void)
2813 2814 2815
{
	memset(early_node_map, 0, sizeof(early_node_map));
	nr_nodemap_entries = 0;
2816 2817 2818 2819
#ifdef CONFIG_MEMORY_HOTPLUG_RESERVE
	memset(node_boundary_start_pfn, 0, sizeof(node_boundary_start_pfn));
	memset(node_boundary_end_pfn, 0, sizeof(node_boundary_end_pfn));
#endif /* CONFIG_MEMORY_HOTPLUG_RESERVE */
2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844
}

/* Compare two active node_active_regions */
static int __init cmp_node_active_region(const void *a, const void *b)
{
	struct node_active_region *arange = (struct node_active_region *)a;
	struct node_active_region *brange = (struct node_active_region *)b;

	/* Done this way to avoid overflows */
	if (arange->start_pfn > brange->start_pfn)
		return 1;
	if (arange->start_pfn < brange->start_pfn)
		return -1;

	return 0;
}

/* sort the node_map by start_pfn */
static void __init sort_node_map(void)
{
	sort(early_node_map, (size_t)nr_nodemap_entries,
			sizeof(struct node_active_region),
			cmp_node_active_region, NULL);
}

2845
/* Find the lowest pfn for a node */
2846 2847 2848
unsigned long __init find_min_pfn_for_node(unsigned long nid)
{
	int i;
2849
	unsigned long min_pfn = ULONG_MAX;
2850

2851 2852
	/* Assuming a sorted map, the first range found has the starting pfn */
	for_each_active_range_index_in_nid(i, nid)
2853
		min_pfn = min(min_pfn, early_node_map[i].start_pfn);
2854

2855 2856 2857 2858 2859 2860 2861
	if (min_pfn == ULONG_MAX) {
		printk(KERN_WARNING
			"Could not find start_pfn for node %lu\n", nid);
		return 0;
	}

	return min_pfn;
2862 2863 2864 2865 2866 2867
}

/**
 * find_min_pfn_with_active_regions - Find the minimum PFN registered
 *
 * It returns the minimum PFN based on information provided via
2868
 * add_active_range().
2869 2870 2871 2872 2873 2874 2875 2876 2877 2878
 */
unsigned long __init find_min_pfn_with_active_regions(void)
{
	return find_min_pfn_for_node(MAX_NUMNODES);
}

/**
 * find_max_pfn_with_active_regions - Find the maximum PFN registered
 *
 * It returns the maximum PFN based on information provided via
2879
 * add_active_range().
2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893
 */
unsigned long __init find_max_pfn_with_active_regions(void)
{
	int i;
	unsigned long max_pfn = 0;

	for (i = 0; i < nr_nodemap_entries; i++)
		max_pfn = max(max_pfn, early_node_map[i].end_pfn);

	return max_pfn;
}

/**
 * free_area_init_nodes - Initialise all pg_data_t and zone data
2894
 * @max_zone_pfn: an array of max PFNs for each zone
2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909
 *
 * This will call free_area_init_node() for each active node in the system.
 * Using the page ranges provided by add_active_range(), the size of each
 * zone in each node and their holes is calculated. If the maximum PFN
 * between two adjacent zones match, it is assumed that the zone is empty.
 * For example, if arch_max_dma_pfn == arch_max_dma32_pfn, it is assumed
 * that arch_max_dma32_pfn has no pages. It is also assumed that a zone
 * starts where the previous one ended. For example, ZONE_DMA32 starts
 * at arch_max_dma_pfn.
 */
void __init free_area_init_nodes(unsigned long *max_zone_pfn)
{
	unsigned long nid;
	enum zone_type i;

2910 2911 2912
	/* Sort early_node_map as initialisation assumes it is sorted */
	sort_node_map();

2913 2914 2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950
	/* Record where the zone boundaries are */
	memset(arch_zone_lowest_possible_pfn, 0,
				sizeof(arch_zone_lowest_possible_pfn));
	memset(arch_zone_highest_possible_pfn, 0,
				sizeof(arch_zone_highest_possible_pfn));
	arch_zone_lowest_possible_pfn[0] = find_min_pfn_with_active_regions();
	arch_zone_highest_possible_pfn[0] = max_zone_pfn[0];
	for (i = 1; i < MAX_NR_ZONES; i++) {
		arch_zone_lowest_possible_pfn[i] =
			arch_zone_highest_possible_pfn[i-1];
		arch_zone_highest_possible_pfn[i] =
			max(max_zone_pfn[i], arch_zone_lowest_possible_pfn[i]);
	}

	/* Print out the zone ranges */
	printk("Zone PFN ranges:\n");
	for (i = 0; i < MAX_NR_ZONES; i++)
		printk("  %-8s %8lu -> %8lu\n",
				zone_names[i],
				arch_zone_lowest_possible_pfn[i],
				arch_zone_highest_possible_pfn[i]);

	/* Print out the early_node_map[] */
	printk("early_node_map[%d] active PFN ranges\n", nr_nodemap_entries);
	for (i = 0; i < nr_nodemap_entries; i++)
		printk("  %3d: %8lu -> %8lu\n", early_node_map[i].nid,
						early_node_map[i].start_pfn,
						early_node_map[i].end_pfn);

	/* Initialise every node */
	for_each_online_node(nid) {
		pg_data_t *pgdat = NODE_DATA(nid);
		free_area_init_node(nid, pgdat, NULL,
				find_min_pfn_for_node(nid), NULL);
	}
}
#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */

2951
/**
2952 2953
 * set_dma_reserve - set the specified number of pages reserved in the first zone
 * @new_dma_reserve: The number of pages to mark reserved
2954 2955 2956 2957
 *
 * The per-cpu batchsize and zone watermarks are determined by present_pages.
 * In the DMA zone, a significant percentage may be consumed by kernel image
 * and other unfreeable allocations which can skew the watermarks badly. This
2958 2959 2960
 * function may optionally be used to account for unfreeable pages in the
 * first zone (e.g., ZONE_DMA). The effect will be lower watermarks and
 * smaller per-cpu batchsize.
2961 2962 2963 2964 2965 2966
 */
void __init set_dma_reserve(unsigned long new_dma_reserve)
{
	dma_reserve = new_dma_reserve;
}

2967
#ifndef CONFIG_NEED_MULTIPLE_NODES
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static bootmem_data_t contig_bootmem_data;
struct pglist_data contig_page_data = { .bdata = &contig_bootmem_data };

EXPORT_SYMBOL(contig_page_data);
2972
#endif
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void __init free_area_init(unsigned long *zones_size)
{
2976
	free_area_init_node(0, NODE_DATA(0), zones_size,
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			__pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
}

static int page_alloc_cpu_notify(struct notifier_block *self,
				 unsigned long action, void *hcpu)
{
	int cpu = (unsigned long)hcpu;

	if (action == CPU_DEAD) {
		local_irq_disable();
		__drain_pages(cpu);
2988
		vm_events_fold_cpu(cpu);
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		local_irq_enable();
2990
		refresh_cpu_vm_stats(cpu);
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	}
	return NOTIFY_OK;
}

void __init page_alloc_init(void)
{
	hotcpu_notifier(page_alloc_cpu_notify, 0);
}

3000 3001 3002 3003 3004 3005 3006 3007
/*
 * calculate_totalreserve_pages - called when sysctl_lower_zone_reserve_ratio
 *	or min_free_kbytes changes.
 */
static void calculate_totalreserve_pages(void)
{
	struct pglist_data *pgdat;
	unsigned long reserve_pages = 0;
3008
	enum zone_type i, j;
3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031

	for_each_online_pgdat(pgdat) {
		for (i = 0; i < MAX_NR_ZONES; i++) {
			struct zone *zone = pgdat->node_zones + i;
			unsigned long max = 0;

			/* Find valid and maximum lowmem_reserve in the zone */
			for (j = i; j < MAX_NR_ZONES; j++) {
				if (zone->lowmem_reserve[j] > max)
					max = zone->lowmem_reserve[j];
			}

			/* we treat pages_high as reserved pages. */
			max += zone->pages_high;

			if (max > zone->present_pages)
				max = zone->present_pages;
			reserve_pages += max;
		}
	}
	totalreserve_pages = reserve_pages;
}

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/*
 * setup_per_zone_lowmem_reserve - called whenever
 *	sysctl_lower_zone_reserve_ratio changes.  Ensures that each zone
 *	has a correct pages reserved value, so an adequate number of
 *	pages are left in the zone after a successful __alloc_pages().
 */
static void setup_per_zone_lowmem_reserve(void)
{
	struct pglist_data *pgdat;
3041
	enum zone_type j, idx;
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3042

3043
	for_each_online_pgdat(pgdat) {
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3044 3045 3046 3047 3048 3049
		for (j = 0; j < MAX_NR_ZONES; j++) {
			struct zone *zone = pgdat->node_zones + j;
			unsigned long present_pages = zone->present_pages;

			zone->lowmem_reserve[j] = 0;

3050 3051
			idx = j;
			while (idx) {
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3052 3053
				struct zone *lower_zone;

3054 3055
				idx--;

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				if (sysctl_lowmem_reserve_ratio[idx] < 1)
					sysctl_lowmem_reserve_ratio[idx] = 1;

				lower_zone = pgdat->node_zones + idx;
				lower_zone->lowmem_reserve[j] = present_pages /
					sysctl_lowmem_reserve_ratio[idx];
				present_pages += lower_zone->present_pages;
			}
		}
	}
3066 3067 3068

	/* update totalreserve_pages */
	calculate_totalreserve_pages();
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}

3071 3072 3073 3074 3075
/**
 * setup_per_zone_pages_min - called when min_free_kbytes changes.
 *
 * Ensures that the pages_{min,low,high} values for each zone are set correctly
 * with respect to min_free_kbytes.
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 */
3077
void setup_per_zone_pages_min(void)
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{
	unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
	unsigned long lowmem_pages = 0;
	struct zone *zone;
	unsigned long flags;

	/* Calculate total number of !ZONE_HIGHMEM pages */
	for_each_zone(zone) {
		if (!is_highmem(zone))
			lowmem_pages += zone->present_pages;
	}

	for_each_zone(zone) {
3091 3092
		u64 tmp;

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		spin_lock_irqsave(&zone->lru_lock, flags);
3094 3095
		tmp = (u64)pages_min * zone->present_pages;
		do_div(tmp, lowmem_pages);
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		if (is_highmem(zone)) {
			/*
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			 * __GFP_HIGH and PF_MEMALLOC allocations usually don't
			 * need highmem pages, so cap pages_min to a small
			 * value here.
			 *
			 * The (pages_high-pages_low) and (pages_low-pages_min)
			 * deltas controls asynch page reclaim, and so should
			 * not be capped for highmem.
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			 */
			int min_pages;

			min_pages = zone->present_pages / 1024;
			if (min_pages < SWAP_CLUSTER_MAX)
				min_pages = SWAP_CLUSTER_MAX;
			if (min_pages > 128)
				min_pages = 128;
			zone->pages_min = min_pages;
		} else {
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			/*
			 * If it's a lowmem zone, reserve a number of pages
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3117 3118
			 * proportionate to the zone's size.
			 */
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			zone->pages_min = tmp;
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3120 3121
		}

3122 3123
		zone->pages_low   = zone->pages_min + (tmp >> 2);
		zone->pages_high  = zone->pages_min + (tmp >> 1);
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3124 3125
		spin_unlock_irqrestore(&zone->lru_lock, flags);
	}
3126 3127 3128

	/* update totalreserve_pages */
	calculate_totalreserve_pages();
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}

/*
 * Initialise min_free_kbytes.
 *
 * For small machines we want it small (128k min).  For large machines
 * we want it large (64MB max).  But it is not linear, because network
 * bandwidth does not increase linearly with machine size.  We use
 *
 * 	min_free_kbytes = 4 * sqrt(lowmem_kbytes), for better accuracy:
 *	min_free_kbytes = sqrt(lowmem_kbytes * 16)
 *
 * which yields
 *
 * 16MB:	512k
 * 32MB:	724k
 * 64MB:	1024k
 * 128MB:	1448k
 * 256MB:	2048k
 * 512MB:	2896k
 * 1024MB:	4096k
 * 2048MB:	5792k
 * 4096MB:	8192k
 * 8192MB:	11584k
 * 16384MB:	16384k
 */
static int __init init_per_zone_pages_min(void)
{
	unsigned long lowmem_kbytes;

	lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);

	min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
	if (min_free_kbytes < 128)
		min_free_kbytes = 128;
	if (min_free_kbytes > 65536)
		min_free_kbytes = 65536;
	setup_per_zone_pages_min();
	setup_per_zone_lowmem_reserve();
	return 0;
}
module_init(init_per_zone_pages_min)

/*
 * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so 
 *	that we can call two helper functions whenever min_free_kbytes
 *	changes.
 */
int min_free_kbytes_sysctl_handler(ctl_table *table, int write, 
	struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
{
	proc_dointvec(table, write, file, buffer, length, ppos);
	setup_per_zone_pages_min();
	return 0;
}

3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196
#ifdef CONFIG_NUMA
int sysctl_min_unmapped_ratio_sysctl_handler(ctl_table *table, int write,
	struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
{
	struct zone *zone;
	int rc;

	rc = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
	if (rc)
		return rc;

	for_each_zone(zone)
3197
		zone->min_unmapped_pages = (zone->present_pages *
3198 3199 3200
				sysctl_min_unmapped_ratio) / 100;
	return 0;
}
3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216

int sysctl_min_slab_ratio_sysctl_handler(ctl_table *table, int write,
	struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
{
	struct zone *zone;
	int rc;

	rc = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
	if (rc)
		return rc;

	for_each_zone(zone)
		zone->min_slab_pages = (zone->present_pages *
				sysctl_min_slab_ratio) / 100;
	return 0;
}
3217 3218
#endif

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/*
 * lowmem_reserve_ratio_sysctl_handler - just a wrapper around
 *	proc_dointvec() so that we can call setup_per_zone_lowmem_reserve()
 *	whenever sysctl_lowmem_reserve_ratio changes.
 *
 * The reserve ratio obviously has absolutely no relation with the
 * pages_min watermarks. The lowmem reserve ratio can only make sense
 * if in function of the boot time zone sizes.
 */
int lowmem_reserve_ratio_sysctl_handler(ctl_table *table, int write,
	struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
{
	proc_dointvec_minmax(table, write, file, buffer, length, ppos);
	setup_per_zone_lowmem_reserve();
	return 0;
}

3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261
/*
 * percpu_pagelist_fraction - changes the pcp->high for each zone on each
 * cpu.  It is the fraction of total pages in each zone that a hot per cpu pagelist
 * can have before it gets flushed back to buddy allocator.
 */

int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
	struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
{
	struct zone *zone;
	unsigned int cpu;
	int ret;

	ret = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
	if (!write || (ret == -EINVAL))
		return ret;
	for_each_zone(zone) {
		for_each_online_cpu(cpu) {
			unsigned long  high;
			high = zone->present_pages / percpu_pagelist_fraction;
			setup_pagelist_highmark(zone_pcp(zone, cpu), high);
		}
	}
	return 0;
}

3262
int hashdist = HASHDIST_DEFAULT;
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#ifdef CONFIG_NUMA
static int __init set_hashdist(char *str)
{
	if (!str)
		return 0;
	hashdist = simple_strtoul(str, &str, 0);
	return 1;
}
__setup("hashdist=", set_hashdist);
#endif

/*
 * allocate a large system hash table from bootmem
 * - it is assumed that the hash table must contain an exact power-of-2
 *   quantity of entries
 * - limit is the number of hash buckets, not the total allocation size
 */
void *__init alloc_large_system_hash(const char *tablename,
				     unsigned long bucketsize,
				     unsigned long numentries,
				     int scale,
				     int flags,
				     unsigned int *_hash_shift,
				     unsigned int *_hash_mask,
				     unsigned long limit)
{
	unsigned long long max = limit;
	unsigned long log2qty, size;
	void *table = NULL;

	/* allow the kernel cmdline to have a say */
	if (!numentries) {
		/* round applicable memory size up to nearest megabyte */
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		numentries = nr_kernel_pages;
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		numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
		numentries >>= 20 - PAGE_SHIFT;
		numentries <<= 20 - PAGE_SHIFT;

		/* limit to 1 bucket per 2^scale bytes of low memory */
		if (scale > PAGE_SHIFT)
			numentries >>= (scale - PAGE_SHIFT);
		else
			numentries <<= (PAGE_SHIFT - scale);
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		/* Make sure we've got at least a 0-order allocation.. */
		if (unlikely((numentries * bucketsize) < PAGE_SIZE))
			numentries = PAGE_SIZE / bucketsize;
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	}
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	numentries = roundup_pow_of_two(numentries);
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	/* limit allocation size to 1/16 total memory by default */
	if (max == 0) {
		max = ((unsigned long long)nr_all_pages << PAGE_SHIFT) >> 4;
		do_div(max, bucketsize);
	}

	if (numentries > max)
		numentries = max;

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	log2qty = ilog2(numentries);
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	do {
		size = bucketsize << log2qty;
		if (flags & HASH_EARLY)
			table = alloc_bootmem(size);
		else if (hashdist)
			table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
		else {
			unsigned long order;
			for (order = 0; ((1UL << order) << PAGE_SHIFT) < size; order++)
				;
			table = (void*) __get_free_pages(GFP_ATOMIC, order);
		}
	} while (!table && size > PAGE_SIZE && --log2qty);

	if (!table)
		panic("Failed to allocate %s hash table\n", tablename);

	printk("%s hash table entries: %d (order: %d, %lu bytes)\n",
	       tablename,
	       (1U << log2qty),
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	       ilog2(size) - PAGE_SHIFT,
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	       size);

	if (_hash_shift)
		*_hash_shift = log2qty;
	if (_hash_mask)
		*_hash_mask = (1 << log2qty) - 1;

	return table;
}
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#ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
struct page *pfn_to_page(unsigned long pfn)
{
3359
	return __pfn_to_page(pfn);
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}
unsigned long page_to_pfn(struct page *page)
{
3363
	return __page_to_pfn(page);
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}
EXPORT_SYMBOL(pfn_to_page);
EXPORT_SYMBOL(page_to_pfn);
#endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
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#if MAX_NUMNODES > 1
/*
 * Find the highest possible node id.
 */
int highest_possible_node_id(void)
{
	unsigned int node;
	unsigned int highest = 0;

	for_each_node_mask(node, node_possible_map)
		highest = node;
	return highest;
}
EXPORT_SYMBOL(highest_possible_node_id);
#endif