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linux/mm/page_alloc.c
Linus Torvalds 6fd6b17c6d Revert "[PATCH] mm: micro optimise zone_watermark_ok" 
This reverts commit e80ee884ae.

Pawel Sikora had a boot-time oops due to it - because the sign change
invalidates the following comparisons, since 'free_pages' can be
negative.

The micro-optimization just isn't worth it.

Bisected-by: Pawel Sikora <pluto@agmk.net>
Acked-by: Andrew Morton <akpm@osdl.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-01-31 16:46:40 -08:00

3412 lines
91 KiB
C
Raw Blame History

/*
* 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>
#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 <linux/sort.h>
#include <linux/pfn.h>
#include <linux/backing-dev.h>
#include <linux/fault-inject.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 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,
#ifdef CONFIG_ZONE_DMA32
256,
#endif
#ifdef CONFIG_HIGHMEM
32
#endif
};
EXPORT_SYMBOL(totalram_pages);
static char * const zone_names[MAX_NR_ZONES] = {
"DMA",
#ifdef CONFIG_ZONE_DMA32
"DMA32",
#endif
"Normal",
#ifdef CONFIG_HIGHMEM
"HighMem"
#endif
};
int min_free_kbytes = 1024;
unsigned long __meminitdata nr_kernel_pages;
unsigned long __meminitdata nr_all_pages;
static unsigned long __initdata dma_reserve;
#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];
#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 */
#endif /* CONFIG_ARCH_POPULATES_NODE_MAP */
#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;
set_compound_page_dtor(page, free_compound_page);
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;
VM_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.
*/
VM_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);
VM_BUG_ON(page_idx & (order_size - 1));
VM_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;
VM_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)
{
spin_lock(&zone->lock);
zone->all_unreclaimable = 0;
zone->pages_scanned = 0;
__free_one_page(page, zone, order);
spin_unlock(&zone->lock);
}
static void __free_pages_ok(struct page *page, unsigned int order)
{
unsigned long flags;
int i;
int reserved = 0;
for (i = 0 ; i < (1 << order) ; ++i)
reserved += free_pages_check(page + i);
if (reserved)
return;
if (!PageHighMem(page))
debug_check_no_locks_freed(page_address(page),PAGE_SIZE<<order);
arch_free_page(page, order);
kernel_map_pages(page, 1 << order, 0);
local_irq_save(flags);
__count_vm_events(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;
VM_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);
arch_alloc_page(page, order);
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
* belongs 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;
enum zone_type 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;
if (!populated_zone(zone))
continue;
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) {
int to_drain;
local_irq_save(flags);
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;
local_irq_restore(flags);
}
}
}
}
#endif
static void __drain_pages(unsigned int cpu)
{
unsigned long flags;
struct zone *zone;
int i;
for_each_zone(zone) {
struct per_cpu_pageset *pset;
if (!populated_zone(zone))
continue;
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);
}
}
}
#ifdef CONFIG_PM
void mark_free_pages(struct zone *zone)
{
unsigned long pfn, max_zone_pfn;
unsigned long flags;
int order;
struct list_head *curr;
if (!zone->spanned_pages)
return;
spin_lock_irqsave(&zone->lock, flags);
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);
}
for (order = MAX_ORDER - 1; order >= 0; --order)
list_for_each(curr, &zone->free_area[order].free_list) {
unsigned long i;
pfn = page_to_pfn(list_entry(curr, struct page, lru));
for (i = 0; i < (1UL << order); i++)
SetPageNosaveFree(pfn_to_page(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 */
/*
* 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;
if (free_pages_check(page))
return;
if (!PageHighMem(page))
debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
arch_free_page(page, 0);
kernel_map_pages(page, 1, 0);
pcp = &zone_pcp(zone, get_cpu())->pcp[cold];
local_irq_save(flags);
__count_vm_event(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;
VM_BUG_ON(PageCompound(page));
VM_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;
}
__count_zone_vm_events(PGALLOC, zone, 1 << order);
zone_statistics(zonelist, zone);
local_irq_restore(flags);
put_cpu();
VM_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 */
#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,
.ignore_gfp_wait = 1,
.ignore_gfp_highmem = 1,
};
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 */
/*
* 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;
}
#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 */
/*
* get_page_from_freelist 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;
struct page *page = NULL;
int classzone_idx = zone_idx(zonelist->zones[0]);
struct zone *zone;
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 */
zonelist_scan:
/*
* Scan zonelist, looking for a zone with enough free.
* See also cpuset_zone_allowed() comment in kernel/cpuset.c.
*/
z = zonelist->zones;
do {
if (NUMA_BUILD && zlc_active &&
!zlc_zone_worth_trying(zonelist, z, allowednodes))
continue;
zone = *z;
if (unlikely(NUMA_BUILD && (gfp_mask & __GFP_THISNODE) &&
zone->zone_pgdat != zonelist->zones[0]->zone_pgdat))
break;
if ((alloc_flags & ALLOC_CPUSET) &&
!cpuset_zone_allowed_softwall(zone, gfp_mask))
goto try_next_zone;
if (!(alloc_flags & ALLOC_NO_WATERMARKS)) {
unsigned long mark;
if (alloc_flags & ALLOC_WMARK_MIN)
mark = zone->pages_min;
else if (alloc_flags & ALLOC_WMARK_LOW)
mark = zone->pages_low;
else
mark = zone->pages_high;
if (!zone_watermark_ok(zone, order, mark,
classzone_idx, alloc_flags)) {
if (!zone_reclaim_mode ||
!zone_reclaim(zone, gfp_mask, order))
goto this_zone_full;
}
}
page = buffered_rmqueue(zonelist, zone, order, gfp_mask);
if (page)
break;
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;
}
} while (*(++z) != NULL);
if (unlikely(NUMA_BUILD && page == NULL && zlc_active)) {
/* Disable zlc cache for second zonelist scan */
zlc_active = 0;
goto zonelist_scan;
}
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);
if (should_fail_alloc_page(gfp_mask, order))
return NULL;
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;
/*
* 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;
for (z = zonelist->zones; *z; z++)
wakeup_kswapd(*z, order);
/*
* 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. */
rebalance:
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) {
congestion_wait(WRITE, HZ/50);
goto nofail_alloc;
}
}
goto nopage;
}
/* Atomic allocations - we can't balance anything */
if (!wait)
goto nopage;
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) {
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
*/
VM_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) {
VM_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 sum = 0;
enum zone_type i;
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));
}
static inline void show_node(struct zone *zone)
{
if (NUMA_BUILD)
printk("Node %d ", zone_to_nid(zone));
}
void si_meminfo(struct sysinfo *val)
{
val->totalram = totalram_pages;
val->sharedram = 0;
val->freeram = nr_free_pages();
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;
val->freeram = nr_free_pages_pgdat(pgdat);
#ifdef CONFIG_HIGHMEM
val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].present_pages;
val->freehigh = pgdat->node_zones[ZONE_HIGHMEM].free_pages;
#else
val->totalhigh = 0;
val->freehigh = 0;
#endif
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)
{
int cpu;
unsigned long active;
unsigned long inactive;
unsigned long free;
struct zone *zone;
for_each_zone(zone) {
if (!populated_zone(zone))
continue;
show_node(zone);
printk("%s per-cpu:\n", zone->name);
for_each_online_cpu(cpu) {
struct per_cpu_pageset *pageset;
pageset = zone_pcp(zone, cpu);
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);
}
}
get_zone_counts(&active, &inactive, &free);
printk("Active:%lu inactive:%lu dirty:%lu writeback:%lu "
"unstable:%lu free:%u slab:%lu mapped:%lu pagetables:%lu\n",
active,
inactive,
global_page_state(NR_FILE_DIRTY),
global_page_state(NR_WRITEBACK),
global_page_state(NR_UNSTABLE_NFS),
nr_free_pages(),
global_page_state(NR_SLAB_RECLAIMABLE) +
global_page_state(NR_SLAB_UNRECLAIMABLE),
global_page_state(NR_FILE_MAPPED),
global_page_state(NR_PAGETABLE));
for_each_zone(zone) {
int i;
if (!populated_zone(zone))
continue;
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;
if (!populated_zone(zone))
continue;
show_node(zone);
printk("%s: ", zone->name);
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, enum zone_type zone_type)
{
struct zone *zone;
BUG_ON(zone_type >= MAX_NR_ZONES);
zone_type++;
do {
zone_type--;
zone = pgdat->node_zones + zone_type;
if (populated_zone(zone)) {
zonelist->zones[nr_zones++] = zone;
check_highest_zone(zone_type);
}
} while (zone_type);
return nr_zones;
}
#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 j, node, local_node;
enum zone_type i;
int prev_node, load;
struct zonelist *zonelist;
nodemask_t used_mask;
/* initialize zonelists */
for (i = 0; i < MAX_NR_ZONES; 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 < MAX_NR_ZONES; i++) {
zonelist = pgdat->node_zonelists + i;
for (j = 0; zonelist->zones[j] != NULL; j++);
j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
zonelist->zones[j] = NULL;
}
}
}
/* 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);
}
}
#else /* CONFIG_NUMA */
static void __meminit build_zonelists(pg_data_t *pgdat)
{
int node, local_node;
enum zone_type i,j;
local_node = pgdat->node_id;
for (i = 0; i < MAX_NR_ZONES; i++) {
struct zonelist *zonelist;
zonelist = pgdat->node_zonelists + i;
j = build_zonelists_node(pgdat, zonelist, 0, i);
/*
* 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, i);
}
for (node = 0; node < local_node; node++) {
if (!node_online(node))
continue;
j = build_zonelists_node(NODE_DATA(node), zonelist, j, i);
}
zonelist->zones[j] = NULL;
}
}
/* 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;
}
#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));
build_zonelist_cache(NODE_DATA(nid));
}
return 0;
}
void __meminit build_all_zonelists(void)
{
if (system_state == SYSTEM_BOOTING) {
__build_all_zonelists(NULL);
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))
/*
* 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, enum memmap_context context)
{
struct page *page;
unsigned long end_pfn = start_pfn + size;
unsigned long pfn;
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
/*
* 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;
}
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;
}
}
#ifndef __HAVE_ARCH_MEMMAP_INIT
#define memmap_init(size, nid, zone, start_pfn) \
memmap_init_zone((size), (nid), (zone), (start_pfn), MEMMAP_EARLY)
#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) {
if (!populated_zone(zone))
continue;
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);
/* Free per_cpu_pageset if it is slab allocated */
if (pset != &boot_pageset[cpu])
kfree(pset);
zone_pcp(zone, cpu) = NULL;
}
}
static int __cpuinit 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 __cpuinitdata 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,
enum memmap_context context)
{
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;
}
#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
* @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
*
* 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
* @nid: The node to call memory_present for. If MAX_NUMNODES, all nodes will be used.
*
* If an architecture guarantees that all ranges registered with
* add_active_ranges() contain no holes and may be freed, this
* function may be used instead of calling memory_present() manually.
*/
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);
}
/**
* 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
/**
* get_pfn_range_for_nid - Return the start and end page frames for a node
* @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.
*
* 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
* PFNs will be 0.
*/
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;
}
/* Push the node boundaries out if requested */
account_node_boundary(nid, start_pfn, end_pfn);
}
/*
* 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,
* then all holes in the requested range will be accounted for.
*/
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;
/* 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;
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;
}
/* Account for ranges past physical memory on this node */
if (range_end_pfn > prev_end_pfn)
hole_pages += range_end_pfn -
max(range_start_pfn, prev_end_pfn);
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
*
* It returns the number of pages frames in memory holes within a range.
*/
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)
{
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);
}
#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];
}
#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);
}
/*
* 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)
{
enum zone_type 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, memmap_pages;
size = zone_spanned_pages_in_node(nid, j, zones_size);
realsize = size - zone_absent_pages_in_node(nid, j,
zholes_size);
/*
* 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);
/* Account for reserved DMA pages */
if (j == ZONE_DMA && realsize > dma_reserve) {
realsize -= dma_reserve;
printk(KERN_DEBUG " DMA zone: %lu pages reserved\n",
dma_reserve);
}
if (!is_highmem_idx(j))
nr_kernel_pages += realsize;
nr_all_pages += realsize;
zone->spanned_pages = size;
zone->present_pages = realsize;
#ifdef CONFIG_NUMA
zone->node = nid;
zone->min_unmapped_pages = (realsize*sysctl_min_unmapped_ratio)
/ 100;
zone->min_slab_pages = (realsize * sysctl_min_slab_ratio) / 100;
#endif
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->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;
zap_zone_vm_stats(zone);
atomic_set(&zone->reclaim_in_progress, 0);
if (!size)
continue;
ret = init_currently_empty_zone(zone, zone_start_pfn,
size, MEMMAP_EARLY);
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;
#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 */
}
#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_node_totalpages(pgdat, zones_size, zholes_size);
alloc_node_mem_map(pgdat);
free_area_init_core(pgdat, zones_size, zholes_size);
}
#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
*
* 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.
*/
void __init remove_all_active_ranges(void)
{
memset(early_node_map, 0, sizeof(early_node_map));
nr_nodemap_entries = 0;
#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 */
}
/* 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);
}
/* Find the lowest pfn for a node. This depends on a sorted early_node_map */
unsigned long __init find_min_pfn_for_node(unsigned long nid)
{
int i;
/* Regions in the early_node_map can be in any order */
sort_node_map();
/* Assuming a sorted map, the first range found has the starting pfn */
for_each_active_range_index_in_nid(i, nid)
return early_node_map[i].start_pfn;
printk(KERN_WARNING "Could not find start_pfn for node %lu\n", nid);
return 0;
}
/**
* find_min_pfn_with_active_regions - Find the minimum PFN registered
*
* It returns the minimum PFN based on information provided via
* add_active_range().
*/
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
* add_active_range().
*/
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
* @max_zone_pfn: an array of max PFNs for each zone
*
* 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;
/* 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 */
/**
* set_dma_reserve - set the specified number of pages reserved in the first zone
* @new_dma_reserve: The number of pages to mark reserved
*
* 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
* 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.
*/
void __init set_dma_reserve(unsigned long new_dma_reserve)
{
dma_reserve = new_dma_reserve;
}
#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);
}
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);
vm_events_fold_cpu(cpu);
local_irq_enable();
refresh_cpu_vm_stats(cpu);
}
return NOTIFY_OK;
}
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;
enum zone_type 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;
enum zone_type 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;
idx = j;
while (idx) {
struct zone *lower_zone;
idx--;
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;
}
#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)
zone->min_unmapped_pages = (zone->present_pages *
sysctl_min_unmapped_ratio) / 100;
return 0;
}
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;
}
#endif
/*
* 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;
}
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 = 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);
/* Make sure we've got at least a 0-order allocation.. */
if (unlikely((numentries * bucketsize) < PAGE_SIZE))
numentries = PAGE_SIZE / bucketsize;
}
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 = ilog2(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),
ilog2(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 */
#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
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