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linux/mm/page_alloc.c

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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/config.h>
#include <linux/stddef.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#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>
#include <linux/memory_hotplug.h>
#include <linux/nodemask.h>
#include <linux/vmalloc.h>
#include <linux/mempolicy.h>
#include <linux/stop_machine.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
#include "internal.h"
/*
* MCD - HACK: Find somewhere to initialize this EARLY, or make this
* initializer cleaner
*/
nodemask_t node_online_map __read_mostly = { { [0] = 1UL } };
EXPORT_SYMBOL(node_online_map);
nodemask_t node_possible_map __read_mostly = NODE_MASK_ALL;
EXPORT_SYMBOL(node_possible_map);
unsigned long totalram_pages __read_mostly;
unsigned long totalhigh_pages __read_mostly;
unsigned long totalreserve_pages __read_mostly;
long nr_swap_pages;
int percpu_pagelist_fraction;
static void __free_pages_ok(struct page *page, unsigned int order);
/*
* 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
*
* TBD: should special case ZONE_DMA32 machines here - in those we normally
* don't need any ZONE_NORMAL reservation
*/
int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES-1] = { 256, 256, 32 };
EXPORT_SYMBOL(totalram_pages);
/*
* Used by page_zone() to look up the address of the struct zone whose
* id is encoded in the upper bits of page->flags
*/
struct zone *zone_table[1 << ZONETABLE_SHIFT] __read_mostly;
EXPORT_SYMBOL(zone_table);
static char *zone_names[MAX_NR_ZONES] = { "DMA", "DMA32", "Normal", "HighMem" };
int min_free_kbytes = 1024;
unsigned long __meminitdata nr_kernel_pages;
unsigned long __meminitdata nr_all_pages;
#ifdef CONFIG_DEBUG_VM
static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
{
int ret = 0;
unsigned seq;
unsigned long pfn = page_to_pfn(page);
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;
}
static int page_is_consistent(struct zone *zone, struct page *page)
{
#ifdef CONFIG_HOLES_IN_ZONE
if (!pfn_valid(page_to_pfn(page)))
return 0;
#endif
if (zone != page_zone(page))
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))
return 1;
if (!page_is_consistent(zone, page))
return 1;
return 0;
}
#else
static inline int bad_range(struct zone *zone, struct page *page)
{
return 0;
}
#endif
static void bad_page(struct page *page)
{
printk(KERN_EMERG "Bad page state in process '%s'\n"
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",
current->comm, page, (int)(2*sizeof(unsigned long)),
(unsigned long)page->flags, page->mapping,
page_mapcount(page), page_count(page));
dump_stack();
page->flags &= ~(1 << PG_lru |
1 << PG_private |
1 << PG_locked |
1 << PG_active |
1 << PG_dirty |
1 << PG_reclaim |
1 << PG_slab |
1 << PG_swapcache |
1 << PG_writeback |
1 << PG_buddy );
set_page_count(page, 0);
reset_page_mapcount(page);
page->mapping = NULL;
add_taint(TAINT_BAD_PAGE);
}
/*
* 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).
*
* 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.
*/
static void free_compound_page(struct page *page)
{
__free_pages_ok(page, (unsigned long)page[1].lru.prev);
}
static void prep_compound_page(struct page *page, unsigned long order)
{
int i;
int nr_pages = 1 << order;
page[1].lru.next = (void *)free_compound_page; /* set dtor */
page[1].lru.prev = (void *)order;
for (i = 0; i < nr_pages; i++) {
struct page *p = page + i;
__SetPageCompound(p);
set_page_private(p, (unsigned long)page);
}
}
static void destroy_compound_page(struct page *page, unsigned long order)
{
int i;
int nr_pages = 1 << order;
if (unlikely((unsigned long)page[1].lru.prev != order))
bad_page(page);
for (i = 0; i < nr_pages; i++) {
struct page *p = page + i;
if (unlikely(!PageCompound(p) |
(page_private(p) != (unsigned long)page)))
bad_page(page);
__ClearPageCompound(p);
}
}
static inline void prep_zero_page(struct page *page, int order, gfp_t gfp_flags)
{
int i;
BUG_ON((gfp_flags & (__GFP_WAIT | __GFP_HIGHMEM)) == __GFP_HIGHMEM);
/*
* clear_highpage() will use KM_USER0, so it's a bug to use __GFP_ZERO
* and __GFP_HIGHMEM from hard or soft interrupt context.
*/
BUG_ON((gfp_flags & __GFP_HIGHMEM) && in_interrupt());
for (i = 0; i < (1 << order); i++)
clear_highpage(page + i);
}
/*
* 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.
*/
static inline unsigned long page_order(struct page *page)
{
return page_private(page);
}
static inline void set_page_order(struct page *page, int order)
{
set_page_private(page, order);
__SetPageBuddy(page);
}
static inline void rmv_page_order(struct page *page)
{
__ClearPageBuddy(page);
set_page_private(page, 0);
}
/*
* 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)
*
* Assumption: *_mem_map is contiguous at least up to MAX_ORDER
*/
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
* (a) the buddy is not in a hole &&
* (b) the buddy is in the buddy system &&
* (c) a page and its buddy have the same order &&
* (d) a page and its buddy are in the same zone.
*
* 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.
*
* For recording page's order, we use page_private(page).
*/
static inline int page_is_buddy(struct page *page, struct page *buddy,
int order)
{
#ifdef CONFIG_HOLES_IN_ZONE
if (!pfn_valid(page_to_pfn(buddy)))
return 0;
#endif
if (page_zone_id(page) != page_zone_id(buddy))
return 0;
if (PageBuddy(buddy) && page_order(buddy) == order) {
BUG_ON(page_count(buddy) != 0);
return 1;
}
return 0;
}
/*
* 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
* free pages of length of (1 << order) and marked with PG_buddy. Page's
* order is recorded in page_private(page) field.
* So when we are allocating or freeing one, we can derive the state of the
* other. That is, if we allocate a small block, and both were
* free, the remainder of the region must be split into blocks.
* If a block is freed, and its buddy is also free, then this
* triggers coalescing into a block of larger size.
*
* -- wli
*/
static inline void __free_one_page(struct page *page,
struct zone *zone, unsigned int order)
{
unsigned long page_idx;
int order_size = 1 << order;
if (unlikely(PageCompound(page)))
destroy_compound_page(page, order);
page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
BUG_ON(page_idx & (order_size - 1));
BUG_ON(bad_range(zone, page));
zone->free_pages += order_size;
while (order < MAX_ORDER-1) {
unsigned long combined_idx;
struct free_area *area;
struct page *buddy;
buddy = __page_find_buddy(page, page_idx, order);
if (!page_is_buddy(page, buddy, order))
break; /* Move the buddy up one level. */
list_del(&buddy->lru);
area = zone->free_area + order;
area->nr_free--;
rmv_page_order(buddy);
combined_idx = __find_combined_index(page_idx, order);
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++;
}
static inline int free_pages_check(struct page *page)
{
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
(page_count(page) != 0) |
(page->flags & (
1 << PG_lru |
1 << PG_private |
1 << PG_locked |
1 << PG_active |
1 << PG_reclaim |
1 << PG_slab |
1 << PG_swapcache |
1 << PG_writeback |
1 << PG_reserved |
1 << PG_buddy ))))
bad_page(page);
if (PageDirty(page))
__ClearPageDirty(page);
/*
* 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);
}
/*
* Frees a list of pages.
* Assumes all pages on list are in same zone, and of same order.
* count is the number of pages to free.
*
* 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.
*/
static void free_pages_bulk(struct zone *zone, int count,
struct list_head *list, int order)
{
spin_lock(&zone->lock);
zone->all_unreclaimable = 0;
zone->pages_scanned = 0;
while (count--) {
struct page *page;
BUG_ON(list_empty(list));
page = list_entry(list->prev, struct page, lru);
/* have to delete it as __free_one_page list manipulates */
list_del(&page->lru);
__free_one_page(page, zone, order);
}
spin_unlock(&zone->lock);
}
static void free_one_page(struct zone *zone, struct page *page, int order)
{
LIST_HEAD(list);
list_add(&page->lru, &list);
free_pages_bulk(zone, 1, &list, order);
}
static void __free_pages_ok(struct page *page, unsigned int order)
{
unsigned long flags;
int i;
int reserved = 0;
arch_free_page(page, order);
if (!PageHighMem(page))
mutex_debug_check_no_locks_freed(page_address(page),
PAGE_SIZE<<order);
for (i = 0 ; i < (1 << order) ; ++i)
reserved += free_pages_check(page + i);
if (reserved)
return;
kernel_map_pages(page, 1 << order, 0);
local_irq_save(flags);
__mod_page_state(pgfree, 1 << order);
free_one_page(page_zone(page), page, order);
local_irq_restore(flags);
}
/*
* 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);
set_page_refcounted(page);
__free_page(page);
} else {
int loop;
prefetchw(page);
for (loop = 0; loop < BITS_PER_LONG; loop++) {
struct page *p = &page[loop];
if (loop + 1 < BITS_PER_LONG)
prefetchw(p + 1);
__ClearPageReserved(p);
set_page_count(p, 0);
}
set_page_refcounted(page);
__free_pages(page, order);
}
}
/*
* 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
*/
static inline void expand(struct zone *zone, struct page *page,
int low, int high, struct free_area *area)
{
unsigned long size = 1 << high;
while (high > low) {
area--;
high--;
size >>= 1;
BUG_ON(bad_range(zone, &page[size]));
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
*/
static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
{
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
(page_count(page) != 0) |
(page->flags & (
1 << PG_lru |
1 << PG_private |
1 << PG_locked |
1 << PG_active |
1 << PG_dirty |
1 << PG_reclaim |
1 << PG_slab |
1 << PG_swapcache |
1 << PG_writeback |
1 << PG_reserved |
1 << PG_buddy ))))
bad_page(page);
/*
* 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;
page->flags &= ~(1 << PG_uptodate | 1 << PG_error |
1 << PG_referenced | 1 << PG_arch_1 |
1 << PG_checked | 1 << PG_mappedtodisk);
set_page_private(page, 0);
set_page_refcounted(page);
kernel_map_pages(page, 1 << order, 1);
if (gfp_flags & __GFP_ZERO)
prep_zero_page(page, order, gfp_flags);
if (order && (gfp_flags & __GFP_COMP))
prep_compound_page(page, order);
return 0;
}
/*
* 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--;
zone->free_pages -= 1UL << order;
expand(zone, page, order, current_order, area);
return page;
}
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;
spin_lock(&zone->lock);
for (i = 0; i < count; ++i) {
struct page *page = __rmqueue(zone, order);
if (unlikely(page == NULL))
break;
list_add_tail(&page->lru, list);
}
spin_unlock(&zone->lock);
return i;
}
#ifdef CONFIG_NUMA
/*
* Called from the slab reaper to drain pagesets on a particular node that
* belong to the currently executing processor.
* Note that this function must be called with the thread pinned to
* a single processor.
*/
void drain_node_pages(int nodeid)
{
int i, z;
unsigned long flags;
for (z = 0; z < MAX_NR_ZONES; z++) {
struct zone *zone = NODE_DATA(nodeid)->node_zones + z;
struct per_cpu_pageset *pset;
pset = zone_pcp(zone, smp_processor_id());
for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
struct per_cpu_pages *pcp;
pcp = &pset->pcp[i];
if (pcp->count) {
local_irq_save(flags);
free_pages_bulk(zone, pcp->count, &pcp->list, 0);
pcp->count = 0;
local_irq_restore(flags);
}
}
}
}
#endif
#if defined(CONFIG_PM) || defined(CONFIG_HOTPLUG_CPU)
static void __drain_pages(unsigned int cpu)
{
unsigned long flags;
struct zone *zone;
int i;
for_each_zone(zone) {
struct per_cpu_pageset *pset;
pset = zone_pcp(zone, cpu);
for (i = 0; i < ARRAY_SIZE(pset->pcp); i++) {
struct per_cpu_pages *pcp;
pcp = &pset->pcp[i];
local_irq_save(flags);
free_pages_bulk(zone, pcp->count, &pcp->list, 0);
pcp->count = 0;
local_irq_restore(flags);
}
}
}
#endif /* CONFIG_PM || CONFIG_HOTPLUG_CPU */
#ifdef CONFIG_PM
void mark_free_pages(struct zone *zone)
{
unsigned long zone_pfn, flags;
int order;
struct list_head *curr;
if (!zone->spanned_pages)
return;
spin_lock_irqsave(&zone->lock, flags);
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
ClearPageNosaveFree(pfn_to_page(zone_pfn + zone->zone_start_pfn));
for (order = MAX_ORDER - 1; order >= 0; --order)
list_for_each(curr, &zone->free_area[order].free_list) {
unsigned long start_pfn, i;
start_pfn = page_to_pfn(list_entry(curr, struct page, lru));
for (i=0; i < (1<<order); i++)
SetPageNosaveFree(pfn_to_page(start_pfn+i));
}
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 */
static void zone_statistics(struct zonelist *zonelist, struct zone *z, int cpu)
{
#ifdef CONFIG_NUMA
pg_data_t *pg = z->zone_pgdat;
pg_data_t *orig = zonelist->zones[0]->zone_pgdat;
struct per_cpu_pageset *p;
p = zone_pcp(z, cpu);
if (pg == orig) {
p->numa_hit++;
} else {
p->numa_miss++;
zone_pcp(zonelist->zones[0], cpu)->numa_foreign++;
}
if (pg == NODE_DATA(numa_node_id()))
p->local_node++;
else
p->other_node++;
#endif
}
/*
* 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;
arch_free_page(page, 0);
if (PageAnon(page))
page->mapping = NULL;
if (free_pages_check(page))
return;
kernel_map_pages(page, 1, 0);
pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
local_irq_save(flags);
__inc_page_state(pgfree);
list_add(&page->lru, &pcp->list);
pcp->count++;
if (pcp->count >= pcp->high) {
free_pages_bulk(zone, pcp->batch, &pcp->list, 0);
pcp->count -= pcp->batch;
}
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);
}
/*
* 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;
BUG_ON(PageCompound(page));
BUG_ON(!page_count(page));
for (i = 1; i < (1 << order); i++)
set_page_refcounted(page + i);
}
/*
* 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.
*/
static struct page *buffered_rmqueue(struct zonelist *zonelist,
struct zone *zone, int order, gfp_t gfp_flags)
{
unsigned long flags;
struct page *page;
int cold = !!(gfp_flags & __GFP_COLD);
int cpu;
again:
cpu = get_cpu();
if (likely(order == 0)) {
struct per_cpu_pages *pcp;
pcp = &zone_pcp(zone, cpu)->pcp[cold];
local_irq_save(flags);
if (!pcp->count) {
pcp->count += rmqueue_bulk(zone, 0,
pcp->batch, &pcp->list);
if (unlikely(!pcp->count))
goto failed;
}
page = list_entry(pcp->list.next, struct page, lru);
list_del(&page->lru);
pcp->count--;
} else {
spin_lock_irqsave(&zone->lock, flags);
page = __rmqueue(zone, order);
spin_unlock(&zone->lock);
if (!page)
goto failed;
}
__mod_page_state_zone(zone, pgalloc, 1 << order);
zone_statistics(zonelist, zone, cpu);
local_irq_restore(flags);
put_cpu();
BUG_ON(bad_range(zone, page));
if (prep_new_page(page, order, gfp_flags))
goto again;
return page;
failed:
local_irq_restore(flags);
put_cpu();
return NULL;
}
#define ALLOC_NO_WATERMARKS 0x01 /* don't check watermarks at all */
#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 */
/*
* 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,
int classzone_idx, int alloc_flags)
{
/* free_pages my go negative - that's OK */
long min = mark, free_pages = z->free_pages - (1 << order) + 1;
int o;
if (alloc_flags & ALLOC_HIGH)
min -= min / 2;
if (alloc_flags & ALLOC_HARDER)
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;
}
/*
* get_page_from_freeliest goes through the zonelist trying to allocate
* a page.
*/
static struct page *
get_page_from_freelist(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, int alloc_flags)
{
struct zone **z = zonelist->zones;
struct page *page = NULL;
int classzone_idx = zone_idx(*z);
/*
* Go through the zonelist once, looking for a zone with enough free.
* See also cpuset_zone_allowed() comment in kernel/cpuset.c.
*/
do {
if ((alloc_flags & ALLOC_CPUSET) &&
!cpuset_zone_allowed(*z, gfp_mask))
continue;
if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
unsigned long mark;
if (alloc_flags & ALLOC_WMARK_MIN)
mark = (*z)->pages_min;
else if (alloc_flags & ALLOC_WMARK_LOW)
mark = (*z)->pages_low;
else
mark = (*z)->pages_high;
if (!zone_watermark_ok(*z, order, mark,
classzone_idx, alloc_flags))
if (!zone_reclaim_mode ||
!zone_reclaim(*z, gfp_mask, order))
continue;
}
page = buffered_rmqueue(zonelist, *z, order, gfp_mask);
if (page) {
break;
}
} while (*(++z) != NULL);
return page;
}
/*
* This is the 'heart' of the zoned buddy allocator.
*/
struct page * fastcall
__alloc_pages(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist)
{
const gfp_t wait = gfp_mask & __GFP_WAIT;
struct zone **z;
struct page *page;
struct reclaim_state reclaim_state;
struct task_struct *p = current;
int do_retry;
int alloc_flags;
int did_some_progress;
might_sleep_if(wait);
restart:
z = zonelist->zones; /* the list of zones suitable for gfp_mask */
if (unlikely(*z == NULL)) {
/* Should this ever happen?? */
return NULL;
}
page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
zonelist, ALLOC_WMARK_LOW|ALLOC_CPUSET);
if (page)
goto got_pg;
do {
wakeup_kswapd(*z, order);
} while (*(++z));
/*
* 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
* policy or is asking for __GFP_HIGH memory. GFP_ATOMIC requests will
* set both ALLOC_HARDER (!wait) and ALLOC_HIGH (__GFP_HIGH).
*/
alloc_flags = ALLOC_WMARK_MIN;
if ((unlikely(rt_task(p)) && !in_interrupt()) || !wait)
alloc_flags |= ALLOC_HARDER;
if (gfp_mask & __GFP_HIGH)
alloc_flags |= ALLOC_HIGH;
if (wait)
alloc_flags |= ALLOC_CPUSET;
/*
* Go through the zonelist again. Let __GFP_HIGH and allocations
* coming from realtime tasks go deeper into reserves.
*
* This is the last chance, in general, before the goto nopage.
* Ignore cpuset if GFP_ATOMIC (!wait) rather than fail alloc.
* See also cpuset_zone_allowed() comment in kernel/cpuset.c.
*/
page = get_page_from_freelist(gfp_mask, order, zonelist, alloc_flags);
if (page)
goto got_pg;
/* This allocation should allow future memory freeing. */
if (((p->flags & PF_MEMALLOC) || unlikely(test_thread_flag(TIF_MEMDIE)))
&& !in_interrupt()) {
if (!(gfp_mask & __GFP_NOMEMALLOC)) {
nofail_alloc:
/* go through the zonelist yet again, ignoring mins */
page = get_page_from_freelist(gfp_mask, order,
zonelist, ALLOC_NO_WATERMARKS);
if (page)
goto got_pg;
if (gfp_mask & __GFP_NOFAIL) {
blk_congestion_wait(WRITE, HZ/50);
goto nofail_alloc;
}
}
goto nopage;
}
/* Atomic allocations - we can't balance anything */
if (!wait)
goto nopage;
rebalance:
cond_resched();
/* We now go into synchronous reclaim */
cpuset_memory_pressure_bump();
p->flags |= PF_MEMALLOC;
reclaim_state.reclaimed_slab = 0;
p->reclaim_state = &reclaim_state;
did_some_progress = try_to_free_pages(zonelist->zones, gfp_mask);
p->reclaim_state = NULL;
p->flags &= ~PF_MEMALLOC;
cond_resched();
if (likely(did_some_progress)) {
page = get_page_from_freelist(gfp_mask, order,
zonelist, alloc_flags);
if (page)
goto got_pg;
} 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.
*/
page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, order,
zonelist, ALLOC_WMARK_HIGH|ALLOC_CPUSET);
if (page)
goto got_pg;
out_of_memory(zonelist, gfp_mask, order);
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) {
blk_congestion_wait(WRITE, HZ/50);
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();
show_mem();
}
got_pg:
return page;
}
EXPORT_SYMBOL(__alloc_pages);
/*
* Common helper functions.
*/
fastcall unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
{
struct page * page;
page = alloc_pages(gfp_mask, order);
if (!page)
return 0;
return (unsigned long) page_address(page);
}
EXPORT_SYMBOL(__get_free_pages);
fastcall unsigned long get_zeroed_page(gfp_t gfp_mask)
{
struct page * page;
/*
* get_zeroed_page() returns a 32-bit address, which cannot represent
* a highmem page
*/
BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
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)
{
if (put_page_testzero(page)) {
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) {
BUG_ON(!virt_addr_valid((void *)addr));
__free_pages(virt_to_page((void *)addr), order);
}
}
EXPORT_SYMBOL(free_pages);
/*
* Total amount of free (allocatable) RAM:
*/
unsigned int nr_free_pages(void)
{
unsigned int sum = 0;
struct zone *zone;
for_each_zone(zone)
sum += zone->free_pages;
return sum;
}
EXPORT_SYMBOL(nr_free_pages);
#ifdef CONFIG_NUMA
unsigned int nr_free_pages_pgdat(pg_data_t *pgdat)
{
unsigned int i, sum = 0;
for (i = 0; i < MAX_NR_ZONES; i++)
sum += pgdat->node_zones[i].free_pages;
return sum;
}
#endif
static unsigned int nr_free_zone_pages(int offset)
{
/* Just pick one node, since fallback list is circular */
pg_data_t *pgdat = NODE_DATA(numa_node_id());
unsigned int sum = 0;
struct zonelist *zonelist = pgdat->node_zonelists + offset;
struct zone **zonep = zonelist->zones;
struct zone *zone;
for (zone = *zonep++; zone; zone = *zonep++) {
unsigned long size = zone->present_pages;
unsigned long high = zone->pages_high;
if (size > high)
sum += size - high;
}
return sum;
}
/*
* Amount of free RAM allocatable within ZONE_DMA and ZONE_NORMAL
*/
unsigned int nr_free_buffer_pages(void)
{
return nr_free_zone_pages(gfp_zone(GFP_USER));
}
/*
* Amount of free RAM allocatable within all zones
*/
unsigned int nr_free_pagecache_pages(void)
{
return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER));
}
#ifdef CONFIG_HIGHMEM
unsigned int nr_free_highpages (void)
{
pg_data_t *pgdat;
unsigned int pages = 0;
for_each_online_pgdat(pgdat)
pages += pgdat->node_zones[ZONE_HIGHMEM].free_pages;
return pages;
}
#endif
#ifdef CONFIG_NUMA
static void show_node(struct zone *zone)
{
printk("Node %d ", zone->zone_pgdat->node_id);
}
#else
#define show_node(zone) do { } while (0)
#endif
/*
* Accumulate the page_state information across all CPUs.
* The result is unavoidably approximate - it can change
* during and after execution of this function.
*/
static DEFINE_PER_CPU(struct page_state, page_states) = {0};
atomic_t nr_pagecache = ATOMIC_INIT(0);
EXPORT_SYMBOL(nr_pagecache);
#ifdef CONFIG_SMP
DEFINE_PER_CPU(long, nr_pagecache_local) = 0;
#endif
static void __get_page_state(struct page_state *ret, int nr, cpumask_t *cpumask)
{
unsigned cpu;
memset(ret, 0, nr * sizeof(unsigned long));
cpus_and(*cpumask, *cpumask, cpu_online_map);
for_each_cpu_mask(cpu, *cpumask) {
unsigned long *in;
unsigned long *out;
unsigned off;
unsigned next_cpu;
in = (unsigned long *)&per_cpu(page_states, cpu);
next_cpu = next_cpu(cpu, *cpumask);
if (likely(next_cpu < NR_CPUS))
prefetch(&per_cpu(page_states, next_cpu));
out = (unsigned long *)ret;
for (off = 0; off < nr; off++)
*out++ += *in++;
}
}
void get_page_state_node(struct page_state *ret, int node)
{
int nr;
cpumask_t mask = node_to_cpumask(node);
nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
nr /= sizeof(unsigned long);
__get_page_state(ret, nr+1, &mask);
}
void get_page_state(struct page_state *ret)
{
int nr;
cpumask_t mask = CPU_MASK_ALL;
nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
nr /= sizeof(unsigned long);
__get_page_state(ret, nr + 1, &mask);
}
void get_full_page_state(struct page_state *ret)
{
cpumask_t mask = CPU_MASK_ALL;
__get_page_state(ret, sizeof(*ret) / sizeof(unsigned long), &mask);
}
unsigned long read_page_state_offset(unsigned long offset)
{
unsigned long ret = 0;
int cpu;
for_each_online_cpu(cpu) {
unsigned long in;
in = (unsigned long)&per_cpu(page_states, cpu) + offset;
ret += *((unsigned long *)in);
}
return ret;
}
void __mod_page_state_offset(unsigned long offset, unsigned long delta)
{
void *ptr;
ptr = &__get_cpu_var(page_states);
*(unsigned long *)(ptr + offset) += delta;
}
EXPORT_SYMBOL(__mod_page_state_offset);
void mod_page_state_offset(unsigned long offset, unsigned long delta)
{
unsigned long flags;
void *ptr;
local_irq_save(flags);
ptr = &__get_cpu_var(page_states);
*(unsigned long *)(ptr + offset) += delta;
local_irq_restore(flags);
}
EXPORT_SYMBOL(mod_page_state_offset);
void __get_zone_counts(unsigned long *active, unsigned long *inactive,
unsigned long *free, struct pglist_data *pgdat)
{
struct zone *zones = pgdat->node_zones;
int i;
*active = 0;
*inactive = 0;
*free = 0;
for (i = 0; i < MAX_NR_ZONES; i++) {
*active += zones[i].nr_active;
*inactive += zones[i].nr_inactive;
*free += zones[i].free_pages;
}
}
void get_zone_counts(unsigned long *active,
unsigned long *inactive, unsigned long *free)
{
struct pglist_data *pgdat;
*active = 0;
*inactive = 0;
*free = 0;
for_each_online_pgdat(pgdat) {
unsigned long l, m, n;
__get_zone_counts(&l, &m, &n, pgdat);
*active += l;
*inactive += m;
*free += n;
}
}
void si_meminfo(struct sysinfo *val)
{
val->totalram = totalram_pages;
val->sharedram = 0;
val->freeram = nr_free_pages();
val->bufferram = nr_blockdev_pages();
#ifdef CONFIG_HIGHMEM
val->totalhigh = totalhigh_pages;
val->freehigh = nr_free_highpages();
#else
val->totalhigh = 0;
val->freehigh = 0;
#endif
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;
val->freeram = nr_free_pages_pgdat(pgdat);
val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
val->freehigh = pgdat->node_zones[ZONE_HIGHMEM].free_pages;
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)
{
struct page_state ps;
int cpu, temperature;
unsigned long active;
unsigned long inactive;
unsigned long free;
struct zone *zone;
for_each_zone(zone) {
show_node(zone);
printk("%s per-cpu:", zone->name);
if (!populated_zone(zone)) {
printk(" empty\n");
continue;
} else
printk("\n");
for_each_online_cpu(cpu) {
struct per_cpu_pageset *pageset;
pageset = zone_pcp(zone, cpu);
for (temperature = 0; temperature < 2; temperature++)
printk("cpu %d %s: high %d, batch %d used:%d\n",
cpu,
temperature ? "cold" : "hot",
pageset->pcp[temperature].high,
pageset->pcp[temperature].batch,
pageset->pcp[temperature].count);
}
}
get_page_state(&ps);
get_zone_counts(&active, &inactive, &free);
printk("Free pages: %11ukB (%ukB HighMem)\n",
K(nr_free_pages()),
K(nr_free_highpages()));
printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu "
"unstable:%lu free:%u slab:%lu mapped:%lu pagetables:%lu\n",
active,
inactive,
ps.nr_dirty,
ps.nr_writeback,
ps.nr_unstable,
nr_free_pages(),
ps.nr_slab,
ps.nr_mapped,
ps.nr_page_table_pages);
for_each_zone(zone) {
int i;
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,
K(zone->free_pages),
K(zone->pages_min),
K(zone->pages_low),
K(zone->pages_high),
K(zone->nr_active),
K(zone->nr_inactive),
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) {
unsigned long nr[MAX_ORDER], flags, order, total = 0;
show_node(zone);
printk("%s: ", zone->name);
if (!populated_zone(zone)) {
printk("empty\n");
continue;
}
spin_lock_irqsave(&zone->lock, flags);
for (order = 0; order < MAX_ORDER; order++) {
nr[order] = zone->free_area[order].nr_free;
total += nr[order] << order;
}
spin_unlock_irqrestore(&zone->lock, flags);
for (order = 0; order < MAX_ORDER; order++)
printk("%lu*%lukB ", nr[order], K(1UL) << order);
printk("= %lukB\n", K(total));
}
show_swap_cache_info();
}
/*
* Builds allocation fallback zone lists.
*
* Add all populated zones of a node to the zonelist.
*/
static int __meminit build_zonelists_node(pg_data_t *pgdat,
struct zonelist *zonelist, int nr_zones, int zone_type)
{
struct zone *zone;
BUG_ON(zone_type > ZONE_HIGHMEM);
do {
zone = pgdat->node_zones + zone_type;
if (populated_zone(zone)) {
#ifndef CONFIG_HIGHMEM
BUG_ON(zone_type > ZONE_NORMAL);
#endif
zonelist->zones[nr_zones++] = zone;
check_highest_zone(zone_type);
}
zone_type--;
} while (zone_type >= 0);
return nr_zones;
}
static inline int highest_zone(int zone_bits)
{
int res = ZONE_NORMAL;
if (zone_bits & (__force int)__GFP_HIGHMEM)
res = ZONE_HIGHMEM;
if (zone_bits & (__force int)__GFP_DMA32)
res = ZONE_DMA32;
if (zone_bits & (__force int)__GFP_DMA)
res = ZONE_DMA;
return res;
}
#ifdef CONFIG_NUMA
#define MAX_NODE_LOAD (num_online_nodes())
static int __meminitdata node_load[MAX_NUMNODES];
/**
* find_next_best_node - find the next node that should appear in a given node's fallback list
* @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.
*/
static int __meminit find_next_best_node(int node, nodemask_t *used_node_mask)
{
int n, val;
int min_val = INT_MAX;
int best_node = -1;
/* Use the local node if we haven't already */
if (!node_isset(node, *used_node_mask)) {
node_set(node, *used_node_mask);
return node;
}
for_each_online_node(n) {
cpumask_t tmp;
/* 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);
/* Penalize nodes under us ("prefer the next node") */
val += (n < node);
/* 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;
}
static void __meminit build_zonelists(pg_data_t *pgdat)
{
int i, j, k, node, local_node;
int prev_node, load;
struct zonelist *zonelist;
nodemask_t used_mask;
/* initialize zonelists */
for (i = 0; i < GFP_ZONETYPES; i++) {
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) {
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;
/*
* 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.
*/
if (distance != node_distance(local_node, prev_node))
node_load[node] += load;
prev_node = node;
load--;
for (i = 0; i < GFP_ZONETYPES; i++) {
zonelist = pgdat->node_zonelists + i;
for (j = 0; zonelist->zones[j] != NULL; j++);
k = highest_zone(i);
j = build_zonelists_node(NODE_DATA(node), zonelist, j, k);
zonelist->zones[j] = NULL;
}
}
}
#else /* CONFIG_NUMA */
static void __meminit build_zonelists(pg_data_t *pgdat)
{
int i, j, k, node, local_node;
local_node = pgdat->node_id;
for (i = 0; i < GFP_ZONETYPES; i++) {
struct zonelist *zonelist;
zonelist = pgdat->node_zonelists + i;
j = 0;
k = highest_zone(i);
j = build_zonelists_node(pgdat, zonelist, j, k);
/*
* 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;
j = build_zonelists_node(NODE_DATA(node), zonelist, j, k);
}
for (node = 0; node < local_node; node++) {
if (!node_online(node))
continue;
j = build_zonelists_node(NODE_DATA(node), zonelist, j, k);
}
zonelist->zones[j] = NULL;
}
}
#endif /* CONFIG_NUMA */
/* return values int ....just for stop_machine_run() */
static int __meminit __build_all_zonelists(void *dummy)
{
int nid;
for_each_online_node(nid)
build_zonelists(NODE_DATA(nid));
return 0;
}
void __meminit build_all_zonelists(void)
{
if (system_state == SYSTEM_BOOTING) {
__build_all_zonelists(0);
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 */
}
vm_total_pages = nr_free_pagecache_pages();
printk("Built %i zonelists. Total pages: %ld\n",
num_online_nodes(), vm_total_pages);
}
/*
* 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
#ifndef CONFIG_MEMORY_HOTPLUG
static inline unsigned long wait_table_hash_nr_entries(unsigned long pages)
{
unsigned long size = 1;
pages /= PAGES_PER_WAITQUEUE;
while (size < pages)
size <<= 1;
/*
* Once we have dozens or even hundreds of threads sleeping
* on IO we've got bigger problems than wait queue collision.
* Limit the size of the wait table to a reasonable size.
*/
size = min(size, 4096UL);
return max(size, 4UL);
}
#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
/*
* 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))
static void __init calculate_zone_totalpages(struct pglist_data *pgdat,
unsigned long *zones_size, unsigned long *zholes_size)
{
unsigned long realtotalpages, totalpages = 0;
int i;
for (i = 0; i < MAX_NR_ZONES; i++)
totalpages += zones_size[i];
pgdat->node_spanned_pages = totalpages;
realtotalpages = totalpages;
if (zholes_size)
for (i = 0; i < MAX_NR_ZONES; i++)
realtotalpages -= zholes_size[i];
pgdat->node_present_pages = realtotalpages;
printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id, realtotalpages);
}
/*
* 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.
*/
void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
unsigned long start_pfn)
{
struct page *page;
unsigned long end_pfn = start_pfn + size;
unsigned long pfn;
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
if (!early_pfn_valid(pfn))
continue;
page = pfn_to_page(pfn);
set_page_links(page, zone, nid, pfn);
init_page_count(page);
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))
set_page_address(page, __va(pfn << PAGE_SHIFT));
#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;
}
}
#define ZONETABLE_INDEX(x, zone_nr) ((x << ZONES_SHIFT) | zone_nr)
void zonetable_add(struct zone *zone, int nid, int zid, unsigned long pfn,
unsigned long size)
{
unsigned long snum = pfn_to_section_nr(pfn);
unsigned long end = pfn_to_section_nr(pfn + size);
if (FLAGS_HAS_NODE)
zone_table[ZONETABLE_INDEX(nid, zid)] = zone;
else
for (; snum <= end; snum++)
zone_table[ZONETABLE_INDEX(snum, zid)] = zone;
}
#ifndef __HAVE_ARCH_MEMMAP_INIT
#define memmap_init(size, nid, zone, start_pfn) \
memmap_init_zone((size), (nid), (zone), (start_pfn))
#endif
static int __cpuinit zone_batchsize(struct zone *zone)
{
int batch;
/*
* The per-cpu-pages pools are set to around 1000th of the
* size of the zone. But no more than 1/2 of a meg.
*
* OK, so we don't know how big the cache is. So guess.
*/
batch = zone->present_pages / 1024;
if (batch * PAGE_SIZE > 512 * 1024)
batch = (512 * 1024) / PAGE_SIZE;
batch /= 4; /* We effectively *= 4 below */
if (batch < 1)
batch = 1;
/*
* 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.
*
* 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.
*/
batch = (1 << (fls(batch + batch/2)-1)) - 1;
return batch;
}
inline void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
{
struct per_cpu_pages *pcp;
memset(p, 0, sizeof(*p));
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;
pcp->batch = max(1UL, batch/2);
INIT_LIST_HEAD(&pcp->list);
}
/*
* 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;
}
#ifdef CONFIG_NUMA
/*
* 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.
*
* 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.
*/
static struct per_cpu_pageset boot_pageset[NR_CPUS];
/*
* Dynamically allocate memory for the
* per cpu pageset array in struct zone.
*/
static int __cpuinit process_zones(int cpu)
{
struct zone *zone, *dzone;
for_each_zone(zone) {
zone_pcp(zone, cpu) = kmalloc_node(sizeof(struct per_cpu_pageset),
GFP_KERNEL, cpu_to_node(cpu));
if (!zone_pcp(zone, cpu))
goto bad;
setup_pageset(zone_pcp(zone, cpu), zone_batchsize(zone));
if (percpu_pagelist_fraction)
setup_pagelist_highmark(zone_pcp(zone, cpu),
(zone->present_pages / percpu_pagelist_fraction));
}
return 0;
bad:
for_each_zone(dzone) {
if (dzone == zone)
break;
kfree(zone_pcp(dzone, cpu));
zone_pcp(dzone, cpu) = NULL;
}
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);
zone_pcp(zone, cpu) = NULL;
kfree(pset);
}
}
static int pageset_cpuup_callback(struct notifier_block *nfb,
unsigned long action,
void *hcpu)
{
int cpu = (long)hcpu;
int ret = NOTIFY_OK;
switch (action) {
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;
}
return ret;
}
static struct notifier_block pageset_notifier =
{ &pageset_cpuup_callback, NULL, 0 };
void __init setup_per_cpu_pageset(void)
{
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
static __meminit
int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
{
int i;
struct pglist_data *pgdat = zone->zone_pgdat;
size_t alloc_size;
/*
* The per-page waitqueue mechanism uses hashed waitqueues
* per zone.
*/
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);
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;
for(i = 0; i < zone->wait_table_hash_nr_entries; ++i)
init_waitqueue_head(zone->wait_table + i);
return 0;
}
static __meminit void zone_pcp_init(struct zone *zone)
{
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 */
zone_pcp(zone, cpu) = &boot_pageset[cpu];
setup_pageset(&boot_pageset[cpu],0);
#else
setup_pageset(zone_pcp(zone,cpu), batch);
#endif
}
if (zone->present_pages)
printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%lu\n",
zone->name, zone->present_pages, batch);
}
__meminit int init_currently_empty_zone(struct zone *zone,
unsigned long zone_start_pfn,
unsigned long size)
{
struct pglist_data *pgdat = zone->zone_pgdat;
int ret;
ret = zone_wait_table_init(zone, size);
if (ret)
return ret;
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);
return 0;
}
/*
* Set up the zone data structures:
* - mark all pages reserved
* - mark all memory queues empty
* - clear the memory bitmaps
*/
static void __meminit free_area_init_core(struct pglist_data *pgdat,
unsigned long *zones_size, unsigned long *zholes_size)
{
unsigned long j;
int nid = pgdat->node_id;
unsigned long zone_start_pfn = pgdat->node_start_pfn;
int ret;
pgdat_resize_init(pgdat);
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;
unsigned long size, realsize;
realsize = size = zones_size[j];
if (zholes_size)
realsize -= zholes_size[j];
if (j < ZONE_HIGHMEM)
nr_kernel_pages += realsize;
nr_all_pages += realsize;
zone->spanned_pages = size;
zone->present_pages = realsize;
zone->name = zone_names[j];
spin_lock_init(&zone->lock);
spin_lock_init(&zone->lru_lock);
zone_seqlock_init(zone);
zone->zone_pgdat = pgdat;
zone->free_pages = 0;
zone->temp_priority = zone->prev_priority = DEF_PRIORITY;
zone_pcp_init(zone);
INIT_LIST_HEAD(&zone->active_list);
INIT_LIST_HEAD(&zone->inactive_list);
zone->nr_scan_active = 0;
zone->nr_scan_inactive = 0;
zone->nr_active = 0;
zone->nr_inactive = 0;
atomic_set(&zone->reclaim_in_progress, 0);
if (!size)
continue;
zonetable_add(zone, nid, j, zone_start_pfn, size);
ret = init_currently_empty_zone(zone, zone_start_pfn, size);
BUG_ON(ret);
zone_start_pfn += size;
}
}
static void __init alloc_node_mem_map(struct pglist_data *pgdat)
{
/* Skip empty nodes */
if (!pgdat->node_spanned_pages)
return;
#ifdef CONFIG_FLAT_NODE_MEM_MAP
/* ia64 gets its own node_mem_map, before this, without bootmem */
if (!pgdat->node_mem_map) {
unsigned long size, start, end;
struct page *map;
/*
* 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);
map = alloc_remap(pgdat->node_id, size);
if (!map)
map = alloc_bootmem_node(pgdat, size);
pgdat->node_mem_map = map + (pgdat->node_start_pfn - start);
}
#ifdef CONFIG_FLATMEM
/*
* With no DISCONTIG, the global mem_map is just set as node 0's
*/
if (pgdat == NODE_DATA(0))
mem_map = NODE_DATA(0)->node_mem_map;
#endif
#endif /* CONFIG_FLAT_NODE_MEM_MAP */
}
void __meminit free_area_init_node(int nid, struct pglist_data *pgdat,
unsigned long *zones_size, unsigned long node_start_pfn,
unsigned long *zholes_size)
{
pgdat->node_id = nid;
pgdat->node_start_pfn = node_start_pfn;
calculate_zone_totalpages(pgdat, zones_size, zholes_size);
alloc_node_mem_map(pgdat);
free_area_init_core(pgdat, zones_size, zholes_size);
}
#ifndef CONFIG_NEED_MULTIPLE_NODES
static bootmem_data_t contig_bootmem_data;
struct pglist_data contig_page_data = { .bdata = &contig_bootmem_data };
EXPORT_SYMBOL(contig_page_data);
#endif
void __init free_area_init(unsigned long *zones_size)
{
free_area_init_node(0, NODE_DATA(0), zones_size,
__pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
}
#ifdef CONFIG_PROC_FS
#include <linux/seq_file.h>
static void *frag_start(struct seq_file *m, loff_t *pos)
{
pg_data_t *pgdat;
loff_t node = *pos;
for (pgdat = first_online_pgdat();
pgdat && node;
pgdat = next_online_pgdat(pgdat))
--node;
return pgdat;
}
static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
{
pg_data_t *pgdat = (pg_data_t *)arg;
(*pos)++;
return next_online_pgdat(pgdat);
}
static void frag_stop(struct seq_file *m, void *arg)
{
}
/*
* This walks the free areas for each zone.
*/
static int frag_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = (pg_data_t *)arg;
struct zone *zone;
struct zone *node_zones = pgdat->node_zones;
unsigned long flags;
int order;
for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
if (!populated_zone(zone))
continue;
spin_lock_irqsave(&zone->lock, flags);
seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
for (order = 0; order < MAX_ORDER; ++order)
seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
spin_unlock_irqrestore(&zone->lock, flags);
seq_putc(m, '\n');
}
return 0;
}
struct seq_operations fragmentation_op = {
.start = frag_start,
.next = frag_next,
.stop = frag_stop,
.show = frag_show,
};
/*
* Output information about zones in @pgdat.
*/
static int zoneinfo_show(struct seq_file *m, void *arg)
{
pg_data_t *pgdat = arg;
struct zone *zone;
struct zone *node_zones = pgdat->node_zones;
unsigned long flags;
for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; zone++) {
int i;
if (!populated_zone(zone))
continue;
spin_lock_irqsave(&zone->lock, flags);
seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
seq_printf(m,
"\n pages free %lu"
"\n min %lu"
"\n low %lu"
"\n high %lu"
"\n active %lu"
"\n inactive %lu"
"\n scanned %lu (a: %lu i: %lu)"
"\n spanned %lu"
"\n present %lu",
zone->free_pages,
zone->pages_min,
zone->pages_low,
zone->pages_high,
zone->nr_active,
zone->nr_inactive,
zone->pages_scanned,
zone->nr_scan_active, zone->nr_scan_inactive,
zone->spanned_pages,
zone->present_pages);
seq_printf(m,
"\n protection: (%lu",
zone->lowmem_reserve[0]);
for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
seq_printf(m,
")"
"\n pagesets");
for_each_online_cpu(i) {
struct per_cpu_pageset *pageset;
int j;
pageset = zone_pcp(zone, i);
for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
if (pageset->pcp[j].count)
break;
}
if (j == ARRAY_SIZE(pageset->pcp))
continue;
for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
seq_printf(m,
"\n cpu: %i pcp: %i"
"\n count: %i"
"\n high: %i"
"\n batch: %i",
i, j,
pageset->pcp[j].count,
pageset->pcp[j].high,
pageset->pcp[j].batch);
}
#ifdef CONFIG_NUMA
seq_printf(m,
"\n numa_hit: %lu"
"\n numa_miss: %lu"
"\n numa_foreign: %lu"
"\n interleave_hit: %lu"
"\n local_node: %lu"
"\n other_node: %lu",
pageset->numa_hit,
pageset->numa_miss,
pageset->numa_foreign,
pageset->interleave_hit,
pageset->local_node,
pageset->other_node);
#endif
}
seq_printf(m,
"\n all_unreclaimable: %u"
"\n prev_priority: %i"
"\n temp_priority: %i"
"\n start_pfn: %lu",
zone->all_unreclaimable,
zone->prev_priority,
zone->temp_priority,
zone->zone_start_pfn);
spin_unlock_irqrestore(&zone->lock, flags);
seq_putc(m, '\n');
}
return 0;
}
struct seq_operations zoneinfo_op = {
.start = frag_start, /* iterate over all zones. The same as in
* fragmentation. */
.next = frag_next,
.stop = frag_stop,
.show = zoneinfo_show,
};
static char *vmstat_text[] = {
"nr_dirty",
"nr_writeback",
"nr_unstable",
"nr_page_table_pages",
"nr_mapped",
"nr_slab",
"pgpgin",
"pgpgout",
"pswpin",
"pswpout",
"pgalloc_high",
"pgalloc_normal",
"pgalloc_dma32",
"pgalloc_dma",
"pgfree",
"pgactivate",
"pgdeactivate",
"pgfault",
"pgmajfault",
"pgrefill_high",
"pgrefill_normal",
"pgrefill_dma32",
"pgrefill_dma",
"pgsteal_high",
"pgsteal_normal",
"pgsteal_dma32",
"pgsteal_dma",
"pgscan_kswapd_high",
"pgscan_kswapd_normal",
"pgscan_kswapd_dma32",
"pgscan_kswapd_dma",
"pgscan_direct_high",
"pgscan_direct_normal",
"pgscan_direct_dma32",
"pgscan_direct_dma",
"pginodesteal",
"slabs_scanned",
"kswapd_steal",
"kswapd_inodesteal",
"pageoutrun",
"allocstall",
"pgrotated",
"nr_bounce",
};
static void *vmstat_start(struct seq_file *m, loff_t *pos)
{
struct page_state *ps;
if (*pos >= ARRAY_SIZE(vmstat_text))
return NULL;
ps = kmalloc(sizeof(*ps), GFP_KERNEL);
m->private = ps;
if (!ps)
return ERR_PTR(-ENOMEM);
get_full_page_state(ps);
ps->pgpgin /= 2; /* sectors -> kbytes */
ps->pgpgout /= 2;
return (unsigned long *)ps + *pos;
}
static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
{
(*pos)++;
if (*pos >= ARRAY_SIZE(vmstat_text))
return NULL;
return (unsigned long *)m->private + *pos;
}
static int vmstat_show(struct seq_file *m, void *arg)
{
unsigned long *l = arg;
unsigned long off = l - (unsigned long *)m->private;
seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
return 0;
}
static void vmstat_stop(struct seq_file *m, void *arg)
{
kfree(m->private);
m->private = NULL;
}
struct seq_operations vmstat_op = {
.start = vmstat_start,
.next = vmstat_next,
.stop = vmstat_stop,
.show = vmstat_show,
};
#endif /* CONFIG_PROC_FS */
#ifdef CONFIG_HOTPLUG_CPU
static int page_alloc_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
int cpu = (unsigned long)hcpu;
long *count;
unsigned long *src, *dest;
if (action == CPU_DEAD) {
int i;
/* Drain local pagecache count. */
count = &per_cpu(nr_pagecache_local, cpu);
atomic_add(*count, &nr_pagecache);
*count = 0;
local_irq_disable();
__drain_pages(cpu);
/* Add dead cpu's page_states to our own. */
dest = (unsigned long *)&__get_cpu_var(page_states);
src = (unsigned long *)&per_cpu(page_states, cpu);
for (i = 0; i < sizeof(struct page_state)/sizeof(unsigned long);
i++) {
dest[i] += src[i];
src[i] = 0;
}
local_irq_enable();
}
return NOTIFY_OK;
}
#endif /* CONFIG_HOTPLUG_CPU */
void __init page_alloc_init(void)
{
hotcpu_notifier(page_alloc_cpu_notify, 0);
}
/*
* 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;
int i, j;
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;
}
/*
* 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;
int j, idx;
for_each_online_pgdat(pgdat) {
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;
for (idx = j-1; idx >= 0; idx--) {
struct zone *lower_zone;
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;
}
}
}
/* update totalreserve_pages */
calculate_totalreserve_pages();
}
/*
* 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.
*/
void setup_per_zone_pages_min(void)
{
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) {
u64 tmp;
spin_lock_irqsave(&zone->lru_lock, flags);
tmp = (u64)pages_min * zone->present_pages;
do_div(tmp, lowmem_pages);
if (is_highmem(zone)) {
/*
* __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.
*/
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 {
/*
* If it's a lowmem zone, reserve a number of pages
* proportionate to the zone's size.
*/
zone->pages_min = tmp;
}
zone->pages_low = zone->pages_min + (tmp >> 2);
zone->pages_high = zone->pages_min + (tmp >> 1);
spin_unlock_irqrestore(&zone->lru_lock, flags);
}
/* update totalreserve_pages */
calculate_totalreserve_pages();
}
/*
* 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;
}
/*
* 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;
}
/*
* 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;
}
__initdata int hashdist = HASHDIST_DEFAULT;
#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 */
numentries = (flags & HASH_HIGHMEM) ? nr_all_pages : nr_kernel_pages;
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);
}
numentries = roundup_pow_of_two(numentries);
/* 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;
log2qty = long_log2(numentries);
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),
long_log2(size) - PAGE_SHIFT,
size);
if (_hash_shift)
*_hash_shift = log2qty;
if (_hash_mask)
*_hash_mask = (1 << log2qty) - 1;
return table;
}
#ifdef CONFIG_OUT_OF_LINE_PFN_TO_PAGE
struct page *pfn_to_page(unsigned long pfn)
{
return __pfn_to_page(pfn);
}
unsigned long page_to_pfn(struct page *page)
{
return __page_to_pfn(page);
}
EXPORT_SYMBOL(pfn_to_page);
EXPORT_SYMBOL(page_to_pfn);
#endif /* CONFIG_OUT_OF_LINE_PFN_TO_PAGE */
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