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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/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/stddef.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/interrupt.h>
#include <linux/pagemap.h>
#include <linux/jiffies.h>
#include <linux/bootmem.h>
#include <linux/memblock.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/kmemcheck.h>
#include <linux/kasan.h>
#include <linux/module.h>
#include <linux/suspend.h>
#include <linux/pagevec.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/ratelimit.h>
#include <linux/oom.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/vmstat.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 <linux/page-isolation.h>
#include <linux/page_ext.h>
#include <linux/debugobjects.h>
#include <linux/kmemleak.h>
#include <linux/compaction.h>
#include <trace/events/kmem.h>
#include <linux/prefetch.h>
#include <linux/mm_inline.h>
#include <linux/migrate.h>
#include <linux/page_ext.h>
#include <linux/hugetlb.h>
#include <linux/sched/rt.h>
#include <linux/page_owner.h>
#include <linux/kthread.h>
#include <asm/sections.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
#include "internal.h"
/* prevent >1 _updater_ of zone percpu pageset ->high and ->batch fields */
static DEFINE_MUTEX(pcp_batch_high_lock);
#define MIN_PERCPU_PAGELIST_FRACTION (8)
#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
DEFINE_PER_CPU(int, numa_node);
EXPORT_PER_CPU_SYMBOL(numa_node);
#endif
#ifdef CONFIG_HAVE_MEMORYLESS_NODES
/*
* N.B., Do NOT reference the '_numa_mem_' per cpu variable directly.
* It will not be defined when CONFIG_HAVE_MEMORYLESS_NODES is not defined.
* Use the accessor functions set_numa_mem(), numa_mem_id() and cpu_to_mem()
* defined in <linux/topology.h>.
*/
DEFINE_PER_CPU(int, _numa_mem_); /* Kernel "local memory" node */
EXPORT_PER_CPU_SYMBOL(_numa_mem_);
int _node_numa_mem_[MAX_NUMNODES];
#endif
/*
* Array of node states.
*/
nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
[N_POSSIBLE] = NODE_MASK_ALL,
[N_ONLINE] = { { [0] = 1UL } },
#ifndef CONFIG_NUMA
[N_NORMAL_MEMORY] = { { [0] = 1UL } },
#ifdef CONFIG_HIGHMEM
[N_HIGH_MEMORY] = { { [0] = 1UL } },
#endif
#ifdef CONFIG_MOVABLE_NODE
[N_MEMORY] = { { [0] = 1UL } },
#endif
[N_CPU] = { { [0] = 1UL } },
#endif /* NUMA */
};
EXPORT_SYMBOL(node_states);
/* Protect totalram_pages and zone->managed_pages */
static DEFINE_SPINLOCK(managed_page_count_lock);
unsigned long totalram_pages __read_mostly;
unsigned long totalreserve_pages __read_mostly;
unsigned long totalcma_pages __read_mostly;
/*
* When calculating the number of globally allowed dirty pages, there
* is a certain number of per-zone reserves that should not be
* considered dirtyable memory. This is the sum of those reserves
* over all existing zones that contribute dirtyable memory.
*/
unsigned long dirty_balance_reserve __read_mostly;
int percpu_pagelist_fraction;
gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK;
/*
* A cached value of the page's pageblock's migratetype, used when the page is
* put on a pcplist. Used to avoid the pageblock migratetype lookup when
* freeing from pcplists in most cases, at the cost of possibly becoming stale.
* Also the migratetype set in the page does not necessarily match the pcplist
* index, e.g. page might have MIGRATE_CMA set but be on a pcplist with any
* other index - this ensures that it will be put on the correct CMA freelist.
*/
static inline int get_pcppage_migratetype(struct page *page)
{
return page->index;
}
static inline void set_pcppage_migratetype(struct page *page, int migratetype)
{
page->index = migratetype;
}
#ifdef CONFIG_PM_SLEEP
/*
* The following functions are used by the suspend/hibernate code to temporarily
* change gfp_allowed_mask in order to avoid using I/O during memory allocations
* while devices are suspended. To avoid races with the suspend/hibernate code,
* they should always be called with pm_mutex held (gfp_allowed_mask also should
* only be modified with pm_mutex held, unless the suspend/hibernate code is
* guaranteed not to run in parallel with that modification).
*/
static gfp_t saved_gfp_mask;
void pm_restore_gfp_mask(void)
{
WARN_ON(!mutex_is_locked(&pm_mutex));
if (saved_gfp_mask) {
gfp_allowed_mask = saved_gfp_mask;
saved_gfp_mask = 0;
}
}
void pm_restrict_gfp_mask(void)
{
WARN_ON(!mutex_is_locked(&pm_mutex));
WARN_ON(saved_gfp_mask);
saved_gfp_mask = gfp_allowed_mask;
gfp_allowed_mask &= ~(__GFP_IO | __GFP_FS);
}
bool pm_suspended_storage(void)
{
if ((gfp_allowed_mask & (__GFP_IO | __GFP_FS)) == (__GFP_IO | __GFP_FS))
return false;
return true;
}
#endif /* CONFIG_PM_SLEEP */
#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
int pageblock_order __read_mostly;
#endif
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 leave (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] = {
#ifdef CONFIG_ZONE_DMA
256,
#endif
#ifdef CONFIG_ZONE_DMA32
256,
#endif
#ifdef CONFIG_HIGHMEM
32,
#endif
32,
};
EXPORT_SYMBOL(totalram_pages);
static char * const zone_names[MAX_NR_ZONES] = {
#ifdef CONFIG_ZONE_DMA
"DMA",
#endif
#ifdef CONFIG_ZONE_DMA32
"DMA32",
#endif
"Normal",
#ifdef CONFIG_HIGHMEM
"HighMem",
#endif
"Movable",
#ifdef CONFIG_ZONE_DEVICE
"Device",
#endif
};
int min_free_kbytes = 1024;
int user_min_free_kbytes = -1;
static unsigned long __meminitdata nr_kernel_pages;
static unsigned long __meminitdata nr_all_pages;
static unsigned long __meminitdata dma_reserve;
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
static unsigned long __meminitdata arch_zone_lowest_possible_pfn[MAX_NR_ZONES];
static unsigned long __meminitdata arch_zone_highest_possible_pfn[MAX_NR_ZONES];
static unsigned long __initdata required_kernelcore;
static unsigned long __initdata required_movablecore;
static unsigned long __meminitdata zone_movable_pfn[MAX_NUMNODES];
/* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
int movable_zone;
EXPORT_SYMBOL(movable_zone);
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
#if MAX_NUMNODES > 1
int nr_node_ids __read_mostly = MAX_NUMNODES;
int nr_online_nodes __read_mostly = 1;
EXPORT_SYMBOL(nr_node_ids);
EXPORT_SYMBOL(nr_online_nodes);
#endif
int page_group_by_mobility_disabled __read_mostly;
#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
static inline void reset_deferred_meminit(pg_data_t *pgdat)
{
pgdat->first_deferred_pfn = ULONG_MAX;
}
/* Returns true if the struct page for the pfn is uninitialised */
static inline bool __meminit early_page_uninitialised(unsigned long pfn)
{
if (pfn >= NODE_DATA(early_pfn_to_nid(pfn))->first_deferred_pfn)
return true;
return false;
}
static inline bool early_page_nid_uninitialised(unsigned long pfn, int nid)
{
if (pfn >= NODE_DATA(nid)->first_deferred_pfn)
return true;
return false;
}
/*
* Returns false when the remaining initialisation should be deferred until
* later in the boot cycle when it can be parallelised.
*/
static inline bool update_defer_init(pg_data_t *pgdat,
unsigned long pfn, unsigned long zone_end,
unsigned long *nr_initialised)
{
/* Always populate low zones for address-contrained allocations */
if (zone_end < pgdat_end_pfn(pgdat))
return true;
/* Initialise at least 2G of the highest zone */
(*nr_initialised)++;
if (*nr_initialised > (2UL << (30 - PAGE_SHIFT)) &&
(pfn & (PAGES_PER_SECTION - 1)) == 0) {
pgdat->first_deferred_pfn = pfn;
return false;
}
return true;
}
#else
static inline void reset_deferred_meminit(pg_data_t *pgdat)
{
}
static inline bool early_page_uninitialised(unsigned long pfn)
{
return false;
}
static inline bool early_page_nid_uninitialised(unsigned long pfn, int nid)
{
return false;
}
static inline bool update_defer_init(pg_data_t *pgdat,
unsigned long pfn, unsigned long zone_end,
unsigned long *nr_initialised)
{
return true;
}
#endif
void set_pageblock_migratetype(struct page *page, int migratetype)
{
if (unlikely(page_group_by_mobility_disabled &&
migratetype < MIGRATE_PCPTYPES))
migratetype = MIGRATE_UNMOVABLE;
set_pageblock_flags_group(page, (unsigned long)migratetype,
PB_migrate, PB_migrate_end);
}
#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);
unsigned long sp, start_pfn;
do {
seq = zone_span_seqbegin(zone);
start_pfn = zone->zone_start_pfn;
sp = zone->spanned_pages;
if (!zone_spans_pfn(zone, pfn))
ret = 1;
} while (zone_span_seqretry(zone, seq));
if (ret)
pr_err("page 0x%lx outside node %d zone %s [ 0x%lx - 0x%lx ]\n",
pfn, zone_to_nid(zone), zone->name,
start_pfn, start_pfn + sp);
return ret;
}
static int page_is_consistent(struct zone *zone, struct page *page)
{
if (!pfn_valid_within(page_to_pfn(page)))
return 0;
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, const char *reason,
unsigned long bad_flags)
{
static unsigned long resume;
static unsigned long nr_shown;
static unsigned long nr_unshown;
/* Don't complain about poisoned pages */
if (PageHWPoison(page)) {
page_mapcount_reset(page); /* remove PageBuddy */
return;
}
/*
* Allow a burst of 60 reports, then keep quiet for that minute;
* or allow a steady drip of one report per second.
*/
if (nr_shown == 60) {
if (time_before(jiffies, resume)) {
nr_unshown++;
goto out;
}
if (nr_unshown) {
printk(KERN_ALERT
"BUG: Bad page state: %lu messages suppressed\n",
nr_unshown);
nr_unshown = 0;
}
nr_shown = 0;
}
if (nr_shown++ == 0)
resume = jiffies + 60 * HZ;
printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n",
current->comm, page_to_pfn(page));
dump_page_badflags(page, reason, bad_flags);
print_modules();
dump_stack();
out:
/* Leave bad fields for debug, except PageBuddy could make trouble */
page_mapcount_reset(page); /* remove PageBuddy */
add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
}
/*
* 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 tail pages have their ->first_page
* pointing at the head page.
*
* 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, compound_order(page));
}
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);
set_compound_order(page, order);
__SetPageHead(page);
for (i = 1; i < nr_pages; i++) {
struct page *p = page + i;
set_page_count(p, 0);
p->first_page = page;
/* Make sure p->first_page is always valid for PageTail() */
smp_wmb();
__SetPageTail(p);
}
}
#ifdef CONFIG_DEBUG_PAGEALLOC
unsigned int _debug_guardpage_minorder;
bool _debug_pagealloc_enabled __read_mostly;
bool _debug_guardpage_enabled __read_mostly;
static int __init early_debug_pagealloc(char *buf)
{
if (!buf)
return -EINVAL;
if (strcmp(buf, "on") == 0)
_debug_pagealloc_enabled = true;
return 0;
}
early_param("debug_pagealloc", early_debug_pagealloc);
static bool need_debug_guardpage(void)
{
/* If we don't use debug_pagealloc, we don't need guard page */
if (!debug_pagealloc_enabled())
return false;
return true;
}
static void init_debug_guardpage(void)
{
if (!debug_pagealloc_enabled())
return;
_debug_guardpage_enabled = true;
}
struct page_ext_operations debug_guardpage_ops = {
.need = need_debug_guardpage,
.init = init_debug_guardpage,
};
static int __init debug_guardpage_minorder_setup(char *buf)
{
unsigned long res;
if (kstrtoul(buf, 10, &res) < 0 || res > MAX_ORDER / 2) {
printk(KERN_ERR "Bad debug_guardpage_minorder value\n");
return 0;
}
_debug_guardpage_minorder = res;
printk(KERN_INFO "Setting debug_guardpage_minorder to %lu\n", res);
return 0;
}
__setup("debug_guardpage_minorder=", debug_guardpage_minorder_setup);
static inline void set_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype)
{
struct page_ext *page_ext;
if (!debug_guardpage_enabled())
return;
page_ext = lookup_page_ext(page);
__set_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
INIT_LIST_HEAD(&page->lru);
set_page_private(page, order);
/* Guard pages are not available for any usage */
__mod_zone_freepage_state(zone, -(1 << order), migratetype);
}
static inline void clear_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype)
{
struct page_ext *page_ext;
if (!debug_guardpage_enabled())
return;
page_ext = lookup_page_ext(page);
__clear_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
set_page_private(page, 0);
if (!is_migrate_isolate(migratetype))
__mod_zone_freepage_state(zone, (1 << order), migratetype);
}
#else
struct page_ext_operations debug_guardpage_ops = { NULL, };
static inline void set_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype) {}
static inline void clear_page_guard(struct zone *zone, struct page *page,
unsigned int order, int migratetype) {}
#endif
static inline void set_page_order(struct page *page, unsigned 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);
}
/*
* 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 set ->_mapcount
* PAGE_BUDDY_MAPCOUNT_VALUE.
* Setting, clearing, and testing _mapcount PAGE_BUDDY_MAPCOUNT_VALUE 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,
unsigned int order)
{
if (!pfn_valid_within(page_to_pfn(buddy)))
return 0;
if (page_is_guard(buddy) && page_order(buddy) == order) {
if (page_zone_id(page) != page_zone_id(buddy))
return 0;
VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
return 1;
}
if (PageBuddy(buddy) && page_order(buddy) == order) {
/*
* zone check is done late to avoid uselessly
* calculating zone/node ids for pages that could
* never merge.
*/
if (page_zone_id(page) != page_zone_id(buddy))
return 0;
VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy);
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 _mapcount
* PAGE_BUDDY_MAPCOUNT_VALUE. 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.
*
* -- nyc
*/
static inline void __free_one_page(struct page *page,
unsigned long pfn,
struct zone *zone, unsigned int order,
int migratetype)
{
unsigned long page_idx;
unsigned long combined_idx;
unsigned long uninitialized_var(buddy_idx);
struct page *buddy;
int max_order = MAX_ORDER;
VM_BUG_ON(!zone_is_initialized(zone));
VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page);
VM_BUG_ON(migratetype == -1);
if (is_migrate_isolate(migratetype)) {
/*
* We restrict max order of merging to prevent merge
* between freepages on isolate pageblock and normal
* pageblock. Without this, pageblock isolation
* could cause incorrect freepage accounting.
*/
max_order = min(MAX_ORDER, pageblock_order + 1);
} else {
__mod_zone_freepage_state(zone, 1 << order, migratetype);
}
page_idx = pfn & ((1 << max_order) - 1);
VM_BUG_ON_PAGE(page_idx & ((1 << order) - 1), page);
VM_BUG_ON_PAGE(bad_range(zone, page), page);
while (order < max_order - 1) {
buddy_idx = __find_buddy_index(page_idx, order);
buddy = page + (buddy_idx - page_idx);
if (!page_is_buddy(page, buddy, order))
break;
/*
* Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page,
* merge with it and move up one order.
*/
if (page_is_guard(buddy)) {
clear_page_guard(zone, buddy, order, migratetype);
} else {
list_del(&buddy->lru);
zone->free_area[order].nr_free--;
rmv_page_order(buddy);
}
combined_idx = buddy_idx & page_idx;
page = page + (combined_idx - page_idx);
page_idx = combined_idx;
order++;
}
set_page_order(page, order);
/*
* If this is not the largest possible page, check if the buddy
* of the next-highest order is free. If it is, it's possible
* that pages are being freed that will coalesce soon. In case,
* that is happening, add the free page to the tail of the list
* so it's less likely to be used soon and more likely to be merged
* as a higher order page
*/
if ((order < MAX_ORDER-2) && pfn_valid_within(page_to_pfn(buddy))) {
struct page *higher_page, *higher_buddy;
combined_idx = buddy_idx & page_idx;
higher_page = page + (combined_idx - page_idx);
buddy_idx = __find_buddy_index(combined_idx, order + 1);
higher_buddy = higher_page + (buddy_idx - combined_idx);
if (page_is_buddy(higher_page, higher_buddy, order + 1)) {
list_add_tail(&page->lru,
&zone->free_area[order].free_list[migratetype]);
goto out;
}
}
list_add(&page->lru, &zone->free_area[order].free_list[migratetype]);
out:
zone->free_area[order].nr_free++;
}
static inline int free_pages_check(struct page *page)
{
const char *bad_reason = NULL;
unsigned long bad_flags = 0;
if (unlikely(page_mapcount(page)))
bad_reason = "nonzero mapcount";
if (unlikely(page->mapping != NULL))
bad_reason = "non-NULL mapping";
if (unlikely(atomic_read(&page->_count) != 0))
bad_reason = "nonzero _count";
if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
}
#ifdef CONFIG_MEMCG
if (unlikely(page->mem_cgroup))
bad_reason = "page still charged to cgroup";
#endif
if (unlikely(bad_reason)) {
bad_page(page, bad_reason, bad_flags);
return 1;
}
page_cpupid_reset_last(page);
if (page->flags & PAGE_FLAGS_CHECK_AT_PREP)
page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
return 0;
}
/*
* Frees a number of pages from the PCP lists
* 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_pcppages_bulk(struct zone *zone, int count,
struct per_cpu_pages *pcp)
{
int migratetype = 0;
int batch_free = 0;
int to_free = count;
unsigned long nr_scanned;
spin_lock(&zone->lock);
nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED);
if (nr_scanned)
__mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
while (to_free) {
struct page *page;
struct list_head *list;
/*
* Remove pages from lists in a round-robin fashion. A
* batch_free count is maintained that is incremented when an
* empty list is encountered. This is so more pages are freed
* off fuller lists instead of spinning excessively around empty
* lists
*/
do {
batch_free++;
if (++migratetype == MIGRATE_PCPTYPES)
migratetype = 0;
list = &pcp->lists[migratetype];
} while (list_empty(list));
/* This is the only non-empty list. Free them all. */
if (batch_free == MIGRATE_PCPTYPES)
batch_free = to_free;
do {
int mt; /* migratetype of the to-be-freed page */
page = list_entry(list->prev, struct page, lru);
/* must delete as __free_one_page list manipulates */
list_del(&page->lru);
mt = get_pcppage_migratetype(page);
/* MIGRATE_ISOLATE page should not go to pcplists */
VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
/* Pageblock could have been isolated meanwhile */
if (unlikely(has_isolate_pageblock(zone)))
mt = get_pageblock_migratetype(page);
__free_one_page(page, page_to_pfn(page), zone, 0, mt);
trace_mm_page_pcpu_drain(page, 0, mt);
} while (--to_free && --batch_free && !list_empty(list));
}
spin_unlock(&zone->lock);
}
static void free_one_page(struct zone *zone,
struct page *page, unsigned long pfn,
unsigned int order,
int migratetype)
{
unsigned long nr_scanned;
spin_lock(&zone->lock);
nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED);
if (nr_scanned)
__mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
if (unlikely(has_isolate_pageblock(zone) ||
is_migrate_isolate(migratetype))) {
migratetype = get_pfnblock_migratetype(page, pfn);
}
__free_one_page(page, pfn, zone, order, migratetype);
spin_unlock(&zone->lock);
}
static int free_tail_pages_check(struct page *head_page, struct page *page)
{
if (!IS_ENABLED(CONFIG_DEBUG_VM))
return 0;
if (unlikely(!PageTail(page))) {
bad_page(page, "PageTail not set", 0);
return 1;
}
if (unlikely(page->first_page != head_page)) {
bad_page(page, "first_page not consistent", 0);
return 1;
}
return 0;
}
static void __meminit __init_single_page(struct page *page, unsigned long pfn,
unsigned long zone, int nid)
{
set_page_links(page, zone, nid, pfn);
init_page_count(page);
page_mapcount_reset(page);
page_cpupid_reset_last(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
}
static void __meminit __init_single_pfn(unsigned long pfn, unsigned long zone,
int nid)
{
return __init_single_page(pfn_to_page(pfn), pfn, zone, nid);
}
#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
static void init_reserved_page(unsigned long pfn)
{
pg_data_t *pgdat;
int nid, zid;
if (!early_page_uninitialised(pfn))
return;
nid = early_pfn_to_nid(pfn);
pgdat = NODE_DATA(nid);
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
struct zone *zone = &pgdat->node_zones[zid];
if (pfn >= zone->zone_start_pfn && pfn < zone_end_pfn(zone))
break;
}
__init_single_pfn(pfn, zid, nid);
}
#else
static inline void init_reserved_page(unsigned long pfn)
{
}
#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
/*
* Initialised pages do not have PageReserved set. This function is
* called for each range allocated by the bootmem allocator and
* marks the pages PageReserved. The remaining valid pages are later
* sent to the buddy page allocator.
*/
void __meminit reserve_bootmem_region(unsigned long start, unsigned long end)
{
unsigned long start_pfn = PFN_DOWN(start);
unsigned long end_pfn = PFN_UP(end);
for (; start_pfn < end_pfn; start_pfn++) {
if (pfn_valid(start_pfn)) {
struct page *page = pfn_to_page(start_pfn);
init_reserved_page(start_pfn);
SetPageReserved(page);
}
}
}
static bool free_pages_prepare(struct page *page, unsigned int order)
{
bool compound = PageCompound(page);
int i, bad = 0;
VM_BUG_ON_PAGE(PageTail(page), page);
VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);
trace_mm_page_free(page, order);
kmemcheck_free_shadow(page, order);
kasan_free_pages(page, order);
if (PageAnon(page))
page->mapping = NULL;
bad += free_pages_check(page);
for (i = 1; i < (1 << order); i++) {
if (compound)
bad += free_tail_pages_check(page, page + i);
bad += free_pages_check(page + i);
}
if (bad)
return false;
reset_page_owner(page, order);
if (!PageHighMem(page)) {
debug_check_no_locks_freed(page_address(page),
PAGE_SIZE << order);
debug_check_no_obj_freed(page_address(page),
PAGE_SIZE << order);
}
arch_free_page(page, order);
kernel_map_pages(page, 1 << order, 0);
return true;
}
static void __free_pages_ok(struct page *page, unsigned int order)
{
unsigned long flags;
int migratetype;
unsigned long pfn = page_to_pfn(page);
if (!free_pages_prepare(page, order))
return;
migratetype = get_pfnblock_migratetype(page, pfn);
local_irq_save(flags);
__count_vm_events(PGFREE, 1 << order);
free_one_page(page_zone(page), page, pfn, order, migratetype);
local_irq_restore(flags);
}
static void __init __free_pages_boot_core(struct page *page,
unsigned long pfn, unsigned int order)
{
unsigned int nr_pages = 1 << order;
struct page *p = page;
unsigned int loop;
prefetchw(p);
for (loop = 0; loop < (nr_pages - 1); loop++, p++) {
prefetchw(p + 1);
__ClearPageReserved(p);
set_page_count(p, 0);
}
__ClearPageReserved(p);
set_page_count(p, 0);
page_zone(page)->managed_pages += nr_pages;
set_page_refcounted(page);
__free_pages(page, order);
}
#if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \
defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
int __meminit early_pfn_to_nid(unsigned long pfn)
{
static DEFINE_SPINLOCK(early_pfn_lock);
int nid;
spin_lock(&early_pfn_lock);
nid = __early_pfn_to_nid(pfn, &early_pfnnid_cache);
if (nid < 0)
nid = 0;
spin_unlock(&early_pfn_lock);
return nid;
}
#endif
#ifdef CONFIG_NODES_SPAN_OTHER_NODES
static inline bool __meminit meminit_pfn_in_nid(unsigned long pfn, int node,
struct mminit_pfnnid_cache *state)
{
int nid;
nid = __early_pfn_to_nid(pfn, state);
if (nid >= 0 && nid != node)
return false;
return true;
}
/* Only safe to use early in boot when initialisation is single-threaded */
static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
{
return meminit_pfn_in_nid(pfn, node, &early_pfnnid_cache);
}
#else
static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
{
return true;
}
static inline bool __meminit meminit_pfn_in_nid(unsigned long pfn, int node,
struct mminit_pfnnid_cache *state)
{
return true;
}
#endif
void __init __free_pages_bootmem(struct page *page, unsigned long pfn,
unsigned int order)
{
if (early_page_uninitialised(pfn))
return;
return __free_pages_boot_core(page, pfn, order);
}
#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
static void __init deferred_free_range(struct page *page,
unsigned long pfn, int nr_pages)
{
int i;
if (!page)
return;
/* Free a large naturally-aligned chunk if possible */
if (nr_pages == MAX_ORDER_NR_PAGES &&
(pfn & (MAX_ORDER_NR_PAGES-1)) == 0) {
set_pageblock_migratetype(page, MIGRATE_MOVABLE);
__free_pages_boot_core(page, pfn, MAX_ORDER-1);
return;
}
for (i = 0; i < nr_pages; i++, page++, pfn++)
__free_pages_boot_core(page, pfn, 0);
}
/* Completion tracking for deferred_init_memmap() threads */
static atomic_t pgdat_init_n_undone __initdata;
static __initdata DECLARE_COMPLETION(pgdat_init_all_done_comp);
static inline void __init pgdat_init_report_one_done(void)
{
if (atomic_dec_and_test(&pgdat_init_n_undone))
complete(&pgdat_init_all_done_comp);
}
/* Initialise remaining memory on a node */
static int __init deferred_init_memmap(void *data)
{
pg_data_t *pgdat = data;
int nid = pgdat->node_id;
struct mminit_pfnnid_cache nid_init_state = { };
unsigned long start = jiffies;
unsigned long nr_pages = 0;
unsigned long walk_start, walk_end;
int i, zid;
struct zone *zone;
unsigned long first_init_pfn = pgdat->first_deferred_pfn;
const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id);
if (first_init_pfn == ULONG_MAX) {
pgdat_init_report_one_done();
return 0;
}
/* Bind memory initialisation thread to a local node if possible */
if (!cpumask_empty(cpumask))
set_cpus_allowed_ptr(current, cpumask);
/* Sanity check boundaries */
BUG_ON(pgdat->first_deferred_pfn < pgdat->node_start_pfn);
BUG_ON(pgdat->first_deferred_pfn > pgdat_end_pfn(pgdat));
pgdat->first_deferred_pfn = ULONG_MAX;
/* Only the highest zone is deferred so find it */
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
zone = pgdat->node_zones + zid;
if (first_init_pfn < zone_end_pfn(zone))
break;
}
for_each_mem_pfn_range(i, nid, &walk_start, &walk_end, NULL) {
unsigned long pfn, end_pfn;
struct page *page = NULL;
struct page *free_base_page = NULL;
unsigned long free_base_pfn = 0;
int nr_to_free = 0;
end_pfn = min(walk_end, zone_end_pfn(zone));
pfn = first_init_pfn;
if (pfn < walk_start)
pfn = walk_start;
if (pfn < zone->zone_start_pfn)
pfn = zone->zone_start_pfn;
for (; pfn < end_pfn; pfn++) {
if (!pfn_valid_within(pfn))
goto free_range;
/*
* Ensure pfn_valid is checked every
* MAX_ORDER_NR_PAGES for memory holes
*/
if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) {
if (!pfn_valid(pfn)) {
page = NULL;
goto free_range;
}
}
if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state)) {
page = NULL;
goto free_range;
}
/* Minimise pfn page lookups and scheduler checks */
if (page && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) {
page++;
} else {
nr_pages += nr_to_free;
deferred_free_range(free_base_page,
free_base_pfn, nr_to_free);
free_base_page = NULL;
free_base_pfn = nr_to_free = 0;
page = pfn_to_page(pfn);
cond_resched();
}
if (page->flags) {
VM_BUG_ON(page_zone(page) != zone);
goto free_range;
}
__init_single_page(page, pfn, zid, nid);
if (!free_base_page) {
free_base_page = page;
free_base_pfn = pfn;
nr_to_free = 0;
}
nr_to_free++;
/* Where possible, batch up pages for a single free */
continue;
free_range:
/* Free the current block of pages to allocator */
nr_pages += nr_to_free;
deferred_free_range(free_base_page, free_base_pfn,
nr_to_free);
free_base_page = NULL;
free_base_pfn = nr_to_free = 0;
}
first_init_pfn = max(end_pfn, first_init_pfn);
}
/* Sanity check that the next zone really is unpopulated */
WARN_ON(++zid < MAX_NR_ZONES && populated_zone(++zone));
pr_info("node %d initialised, %lu pages in %ums\n", nid, nr_pages,
jiffies_to_msecs(jiffies - start));
pgdat_init_report_one_done();
return 0;
}
void __init page_alloc_init_late(void)
{
int nid;
/* There will be num_node_state(N_MEMORY) threads */
atomic_set(&pgdat_init_n_undone, num_node_state(N_MEMORY));
for_each_node_state(nid, N_MEMORY) {
kthread_run(deferred_init_memmap, NODE_DATA(nid), "pgdatinit%d", nid);
}
/* Block until all are initialised */
wait_for_completion(&pgdat_init_all_done_comp);
/* Reinit limits that are based on free pages after the kernel is up */
files_maxfiles_init();
}
#endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
#ifdef CONFIG_CMA
/* Free whole pageblock and set its migration type to MIGRATE_CMA. */
void __init init_cma_reserved_pageblock(struct page *page)
{
unsigned i = pageblock_nr_pages;
struct page *p = page;
do {
__ClearPageReserved(p);
set_page_count(p, 0);
} while (++p, --i);
set_pageblock_migratetype(page, MIGRATE_CMA);
if (pageblock_order >= MAX_ORDER) {
i = pageblock_nr_pages;
p = page;
do {
set_page_refcounted(p);
__free_pages(p, MAX_ORDER - 1);
p += MAX_ORDER_NR_PAGES;
} while (i -= MAX_ORDER_NR_PAGES);
} else {
set_page_refcounted(page);
__free_pages(page, pageblock_order);
}
adjust_managed_page_count(page, pageblock_nr_pages);
}
#endif
/*
* 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.
*
* -- nyc
*/
static inline void expand(struct zone *zone, struct page *page,
int low, int high, struct free_area *area,
int migratetype)
{
unsigned long size = 1 << high;
while (high > low) {
area--;
high--;
size >>= 1;
VM_BUG_ON_PAGE(bad_range(zone, &page[size]), &page[size]);
if (IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) &&
debug_guardpage_enabled() &&
high < debug_guardpage_minorder()) {
/*
* Mark as guard pages (or page), that will allow to
* merge back to allocator when buddy will be freed.
* Corresponding page table entries will not be touched,
* pages will stay not present in virtual address space
*/
set_page_guard(zone, &page[size], high, migratetype);
continue;
}
list_add(&page[size].lru, &area->free_list[migratetype]);
area->nr_free++;
set_page_order(&page[size], high);
}
}
/*
* This page is about to be returned from the page allocator
*/
static inline int check_new_page(struct page *page)
{
const char *bad_reason = NULL;
unsigned long bad_flags = 0;
if (unlikely(page_mapcount(page)))
bad_reason = "nonzero mapcount";
if (unlikely(page->mapping != NULL))
bad_reason = "non-NULL mapping";
if (unlikely(atomic_read(&page->_count) != 0))
bad_reason = "nonzero _count";
if (unlikely(page->flags & __PG_HWPOISON)) {
bad_reason = "HWPoisoned (hardware-corrupted)";
bad_flags = __PG_HWPOISON;
}
if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP)) {
bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
}
#ifdef CONFIG_MEMCG
if (unlikely(page->mem_cgroup))
bad_reason = "page still charged to cgroup";
#endif
if (unlikely(bad_reason)) {
bad_page(page, bad_reason, bad_flags);
return 1;
}
return 0;
}
static int prep_new_page(struct page *page, unsigned int order, gfp_t gfp_flags,
int alloc_flags)
{
int i;
for (i = 0; i < (1 << order); i++) {
struct page *p = page + i;
if (unlikely(check_new_page(p)))
return 1;
}
set_page_private(page, 0);
set_page_refcounted(page);
arch_alloc_page(page, order);
kernel_map_pages(page, 1 << order, 1);
kasan_alloc_pages(page, order);
if (gfp_flags & __GFP_ZERO)
for (i = 0; i < (1 << order); i++)
clear_highpage(page + i);
if (order && (gfp_flags & __GFP_COMP))
prep_compound_page(page, order);
set_page_owner(page, order, gfp_flags);
/*
* page is set pfmemalloc when ALLOC_NO_WATERMARKS was necessary to
* allocate the page. The expectation is that the caller is taking
* steps that will free more memory. The caller should avoid the page
* being used for !PFMEMALLOC purposes.
*/
if (alloc_flags & ALLOC_NO_WATERMARKS)
set_page_pfmemalloc(page);
else
clear_page_pfmemalloc(page);
return 0;
}
/*
* Go through the free lists for the given migratetype and remove
* the smallest available page from the freelists
*/
static inline
struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
int migratetype)
{
unsigned int current_order;
struct free_area *area;
struct page *page;
/* Find a page of the appropriate size in the preferred list */
for (current_order = order; current_order < MAX_ORDER; ++current_order) {
area = &(zone->free_area[current_order]);
if (list_empty(&area->free_list[migratetype]))
continue;
page = list_entry(area->free_list[migratetype].next,
struct page, lru);
list_del(&page->lru);
rmv_page_order(page);
area->nr_free--;
expand(zone, page, order, current_order, area, migratetype);
set_pcppage_migratetype(page, migratetype);
return page;
}
return NULL;
}
/*
* This array describes the order lists are fallen back to when
* the free lists for the desirable migrate type are depleted
*/
static int fallbacks[MIGRATE_TYPES][4] = {
[MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE, MIGRATE_TYPES },
[MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_TYPES },
#ifdef CONFIG_CMA
[MIGRATE_CMA] = { MIGRATE_TYPES }, /* Never used */
#endif
#ifdef CONFIG_MEMORY_ISOLATION
[MIGRATE_ISOLATE] = { MIGRATE_TYPES }, /* Never used */
#endif
};
#ifdef CONFIG_CMA
static struct page *__rmqueue_cma_fallback(struct zone *zone,
unsigned int order)
{
return __rmqueue_smallest(zone, order, MIGRATE_CMA);
}
#else
static inline struct page *__rmqueue_cma_fallback(struct zone *zone,
unsigned int order) { return NULL; }
#endif
/*
* Move the free pages in a range to the free lists of the requested type.
* Note that start_page and end_pages are not aligned on a pageblock
* boundary. If alignment is required, use move_freepages_block()
*/
int move_freepages(struct zone *zone,
struct page *start_page, struct page *end_page,
int migratetype)
{
struct page *page;
unsigned long order;
int pages_moved = 0;
#ifndef CONFIG_HOLES_IN_ZONE
/*
* page_zone is not safe to call in this context when
* CONFIG_HOLES_IN_ZONE is set. This bug check is probably redundant
* anyway as we check zone boundaries in move_freepages_block().
* Remove at a later date when no bug reports exist related to
* grouping pages by mobility
*/
VM_BUG_ON(page_zone(start_page) != page_zone(end_page));
#endif
for (page = start_page; page <= end_page;) {
/* Make sure we are not inadvertently changing nodes */
VM_BUG_ON_PAGE(page_to_nid(page) != zone_to_nid(zone), page);
if (!pfn_valid_within(page_to_pfn(page))) {
page++;
continue;
}
if (!PageBuddy(page)) {
page++;
continue;
}
order = page_order(page);
list_move(&page->lru,
&zone->free_area[order].free_list[migratetype]);
page += 1 << order;
pages_moved += 1 << order;
}
return pages_moved;
}
int move_freepages_block(struct zone *zone, struct page *page,
int migratetype)
{
unsigned long start_pfn, end_pfn;
struct page *start_page, *end_page;
start_pfn = page_to_pfn(page);
start_pfn = start_pfn & ~(pageblock_nr_pages-1);
start_page = pfn_to_page(start_pfn);
end_page = start_page + pageblock_nr_pages - 1;
end_pfn = start_pfn + pageblock_nr_pages - 1;
/* Do not cross zone boundaries */
if (!zone_spans_pfn(zone, start_pfn))
start_page = page;
if (!zone_spans_pfn(zone, end_pfn))
return 0;
return move_freepages(zone, start_page, end_page, migratetype);
}
static void change_pageblock_range(struct page *pageblock_page,
int start_order, int migratetype)
{
int nr_pageblocks = 1 << (start_order - pageblock_order);
while (nr_pageblocks--) {
set_pageblock_migratetype(pageblock_page, migratetype);
pageblock_page += pageblock_nr_pages;
}
}
/*
* When we are falling back to another migratetype during allocation, try to
* steal extra free pages from the same pageblocks to satisfy further
* allocations, instead of polluting multiple pageblocks.
*
* If we are stealing a relatively large buddy page, it is likely there will
* be more free pages in the pageblock, so try to steal them all. For
* reclaimable and unmovable allocations, we steal regardless of page size,
* as fragmentation caused by those allocations polluting movable pageblocks
* is worse than movable allocations stealing from unmovable and reclaimable
* pageblocks.
*/
static bool can_steal_fallback(unsigned int order, int start_mt)
{
/*
* Leaving this order check is intended, although there is
* relaxed order check in next check. The reason is that
* we can actually steal whole pageblock if this condition met,
* but, below check doesn't guarantee it and that is just heuristic
* so could be changed anytime.
*/
if (order >= pageblock_order)
return true;
if (order >= pageblock_order / 2 ||
start_mt == MIGRATE_RECLAIMABLE ||
start_mt == MIGRATE_UNMOVABLE ||
page_group_by_mobility_disabled)
return true;
return false;
}
/*
* This function implements actual steal behaviour. If order is large enough,
* we can steal whole pageblock. If not, we first move freepages in this
* pageblock and check whether half of pages are moved or not. If half of
* pages are moved, we can change migratetype of pageblock and permanently
* use it's pages as requested migratetype in the future.
*/
static void steal_suitable_fallback(struct zone *zone, struct page *page,
int start_type)
{
int current_order = page_order(page);
int pages;
/* Take ownership for orders >= pageblock_order */
if (current_order >= pageblock_order) {
change_pageblock_range(page, current_order, start_type);
return;
}
pages = move_freepages_block(zone, page, start_type);
/* Claim the whole block if over half of it is free */
if (pages >= (1 << (pageblock_order-1)) ||
page_group_by_mobility_disabled)
set_pageblock_migratetype(page, start_type);
}
/*
* Check whether there is a suitable fallback freepage with requested order.
* If only_stealable is true, this function returns fallback_mt only if
* we can steal other freepages all together. This would help to reduce
* fragmentation due to mixed migratetype pages in one pageblock.
*/
int find_suitable_fallback(struct free_area *area, unsigned int order,
int migratetype, bool only_stealable, bool *can_steal)
{
int i;
int fallback_mt;
if (area->nr_free == 0)
return -1;
*can_steal = false;
for (i = 0;; i++) {
fallback_mt = fallbacks[migratetype][i];
if (fallback_mt == MIGRATE_TYPES)
break;
if (list_empty(&area->free_list[fallback_mt]))
continue;
if (can_steal_fallback(order, migratetype))
*can_steal = true;
if (!only_stealable)
return fallback_mt;
if (*can_steal)
return fallback_mt;
}
return -1;
}
/*
* Reserve a pageblock for exclusive use of high-order atomic allocations if
* there are no empty page blocks that contain a page with a suitable order
*/
static void reserve_highatomic_pageblock(struct page *page, struct zone *zone,
unsigned int alloc_order)
{
int mt;
unsigned long max_managed, flags;
/*
* Limit the number reserved to 1 pageblock or roughly 1% of a zone.
* Check is race-prone but harmless.
*/
max_managed = (zone->managed_pages / 100) + pageblock_nr_pages;
if (zone->nr_reserved_highatomic >= max_managed)
return;
spin_lock_irqsave(&zone->lock, flags);
/* Recheck the nr_reserved_highatomic limit under the lock */
if (zone->nr_reserved_highatomic >= max_managed)
goto out_unlock;
/* Yoink! */
mt = get_pageblock_migratetype(page);
if (mt != MIGRATE_HIGHATOMIC &&
!is_migrate_isolate(mt) && !is_migrate_cma(mt)) {
zone->nr_reserved_highatomic += pageblock_nr_pages;
set_pageblock_migratetype(page, MIGRATE_HIGHATOMIC);
move_freepages_block(zone, page, MIGRATE_HIGHATOMIC);
}
out_unlock:
spin_unlock_irqrestore(&zone->lock, flags);
}
/*
* Used when an allocation is about to fail under memory pressure. This
* potentially hurts the reliability of high-order allocations when under
* intense memory pressure but failed atomic allocations should be easier
* to recover from than an OOM.
*/
static void unreserve_highatomic_pageblock(const struct alloc_context *ac)
{
struct zonelist *zonelist = ac->zonelist;
unsigned long flags;
struct zoneref *z;
struct zone *zone;
struct page *page;
int order;
for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx,
ac->nodemask) {
/* Preserve at least one pageblock */
if (zone->nr_reserved_highatomic <= pageblock_nr_pages)
continue;
spin_lock_irqsave(&zone->lock, flags);
for (order = 0; order < MAX_ORDER; order++) {
struct free_area *area = &(zone->free_area[order]);
if (list_empty(&area->free_list[MIGRATE_HIGHATOMIC]))
continue;
page = list_entry(area->free_list[MIGRATE_HIGHATOMIC].next,
struct page, lru);
/*
* It should never happen but changes to locking could
* inadvertently allow a per-cpu drain to add pages
* to MIGRATE_HIGHATOMIC while unreserving so be safe
* and watch for underflows.
*/
zone->nr_reserved_highatomic -= min(pageblock_nr_pages,
zone->nr_reserved_highatomic);
/*
* Convert to ac->migratetype and avoid the normal
* pageblock stealing heuristics. Minimally, the caller
* is doing the work and needs the pages. More
* importantly, if the block was always converted to
* MIGRATE_UNMOVABLE or another type then the number
* of pageblocks that cannot be completely freed
* may increase.
*/
set_pageblock_migratetype(page, ac->migratetype);
move_freepages_block(zone, page, ac->migratetype);
spin_unlock_irqrestore(&zone->lock, flags);
return;
}
spin_unlock_irqrestore(&zone->lock, flags);
}
}
/* Remove an element from the buddy allocator from the fallback list */
static inline struct page *
__rmqueue_fallback(struct zone *zone, unsigned int order, int start_migratetype)
{
struct free_area *area;
unsigned int current_order;
struct page *page;
int fallback_mt;
bool can_steal;
/* Find the largest possible block of pages in the other list */
for (current_order = MAX_ORDER-1;
current_order >= order && current_order <= MAX_ORDER-1;
--current_order) {
area = &(zone->free_area[current_order]);
fallback_mt = find_suitable_fallback(area, current_order,
start_migratetype, false, &can_steal);
if (fallback_mt == -1)
continue;
page = list_entry(area->free_list[fallback_mt].next,
struct page, lru);
if (can_steal)
steal_suitable_fallback(zone, page, start_migratetype);
/* Remove the page from the freelists */
area->nr_free--;
list_del(&page->lru);
rmv_page_order(page);
expand(zone, page, order, current_order, area,
start_migratetype);
/*
* The pcppage_migratetype may differ from pageblock's
* migratetype depending on the decisions in
* find_suitable_fallback(). This is OK as long as it does not
* differ for MIGRATE_CMA pageblocks. Those can be used as
* fallback only via special __rmqueue_cma_fallback() function
*/
set_pcppage_migratetype(page, start_migratetype);
trace_mm_page_alloc_extfrag(page, order, current_order,
start_migratetype, fallback_mt);
return page;
}
return NULL;
}
/*
* 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,
int migratetype, gfp_t gfp_flags)
{
struct page *page;
page = __rmqueue_smallest(zone, order, migratetype);
if (unlikely(!page)) {
if (migratetype == MIGRATE_MOVABLE)
page = __rmqueue_cma_fallback(zone, order);
if (!page)
page = __rmqueue_fallback(zone, order, migratetype);
}
trace_mm_page_alloc_zone_locked(page, order, migratetype);
return page;
}
/*
* 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 migratetype, bool cold)
{
int i;
spin_lock(&zone->lock);
for (i = 0; i < count; ++i) {
struct page *page = __rmqueue(zone, order, migratetype, 0);
if (unlikely(page == NULL))
break;
/*
* Split buddy pages returned by expand() are received here
* in physical page order. The page is added to the callers and
* list and the list head then moves forward. From the callers
* perspective, the linked list is ordered by page number in
* some conditions. This is useful for IO devices that can
* merge IO requests if the physical pages are ordered
* properly.
*/
if (likely(!cold))
list_add(&page->lru, list);
else
list_add_tail(&page->lru, list);
list = &page->lru;
if (is_migrate_cma(get_pcppage_migratetype(page)))
__mod_zone_page_state(zone, NR_FREE_CMA_PAGES,
-(1 << order));
}
__mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
spin_unlock(&zone->lock);
return i;
}
#ifdef CONFIG_NUMA
/*
* Called from the vmstat counter updater to drain pagesets of this
* currently executing processor on remote nodes after they have
* expired.
*
* Note that this function must be called with the thread pinned to
* a single processor.
*/
void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
{
unsigned long flags;
int to_drain, batch;
local_irq_save(flags);
batch = READ_ONCE(pcp->batch);
to_drain = min(pcp->count, batch);
if (to_drain > 0) {
free_pcppages_bulk(zone, to_drain, pcp);
pcp->count -= to_drain;
}
local_irq_restore(flags);
}
#endif
/*
* Drain pcplists of the indicated processor and zone.
*
* The processor must either be the current processor and the
* thread pinned to the current processor or a processor that
* is not online.
*/
static void drain_pages_zone(unsigned int cpu, struct zone *zone)
{
unsigned long flags;
struct per_cpu_pageset *pset;
struct per_cpu_pages *pcp;
local_irq_save(flags);
pset = per_cpu_ptr(zone->pageset, cpu);
pcp = &pset->pcp;
if (pcp->count) {
free_pcppages_bulk(zone, pcp->count, pcp);
pcp->count = 0;
}
local_irq_restore(flags);
}
/*
* Drain pcplists of all zones on the indicated processor.
*
* The processor must either be the current processor and the
* thread pinned to the current processor or a processor that
* is not online.
*/
static void drain_pages(unsigned int cpu)
{
struct zone *zone;
for_each_populated_zone(zone) {
drain_pages_zone(cpu, zone);
}
}
/*
* Spill all of this CPU's per-cpu pages back into the buddy allocator.
*
* The CPU has to be pinned. When zone parameter is non-NULL, spill just
* the single zone's pages.
*/
void drain_local_pages(struct zone *zone)
{
int cpu = smp_processor_id();
if (zone)
drain_pages_zone(cpu, zone);
else
drain_pages(cpu);
}
/*
* Spill all the per-cpu pages from all CPUs back into the buddy allocator.
*
* When zone parameter is non-NULL, spill just the single zone's pages.
*
* Note that this code is protected against sending an IPI to an offline
* CPU but does not guarantee sending an IPI to newly hotplugged CPUs:
* on_each_cpu_mask() blocks hotplug and won't talk to offlined CPUs but
* nothing keeps CPUs from showing up after we populated the cpumask and
* before the call to on_each_cpu_mask().
*/
void drain_all_pages(struct zone *zone)
{
int cpu;
/*
* Allocate in the BSS so we wont require allocation in
* direct reclaim path for CONFIG_CPUMASK_OFFSTACK=y
*/
static cpumask_t cpus_with_pcps;
/*
* We don't care about racing with CPU hotplug event
* as offline notification will cause the notified
* cpu to drain that CPU pcps and on_each_cpu_mask
* disables preemption as part of its processing
*/
for_each_online_cpu(cpu) {
struct per_cpu_pageset *pcp;
struct zone *z;
bool has_pcps = false;
if (zone) {
pcp = per_cpu_ptr(zone->pageset, cpu);
if (pcp->pcp.count)
has_pcps = true;
} else {
for_each_populated_zone(z) {
pcp = per_cpu_ptr(z->pageset, cpu);
if (pcp->pcp.count) {
has_pcps = true;
break;
}
}
}
if (has_pcps)
cpumask_set_cpu(cpu, &cpus_with_pcps);
else
cpumask_clear_cpu(cpu, &cpus_with_pcps);
}
on_each_cpu_mask(&cpus_with_pcps, (smp_call_func_t) drain_local_pages,
zone, 1);
}
#ifdef CONFIG_HIBERNATION
void mark_free_pages(struct zone *zone)
{
unsigned long pfn, max_zone_pfn;
unsigned long flags;
unsigned int order, t;
struct list_head *curr;
if (zone_is_empty(zone))
return;
spin_lock_irqsave(&zone->lock, flags);
max_zone_pfn = zone_end_pfn(zone);
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
if (pfn_valid(pfn)) {
struct page *page = pfn_to_page(pfn);
if (!swsusp_page_is_forbidden(page))
swsusp_unset_page_free(page);
}
for_each_migratetype_order(order, t) {
list_for_each(curr, &zone->free_area[order].free_list[t]) {
unsigned long i;
pfn = page_to_pfn(list_entry(curr, struct page, lru));
for (i = 0; i < (1UL << order); i++)
swsusp_set_page_free(pfn_to_page(pfn + i));
}
}
spin_unlock_irqrestore(&zone->lock, flags);
}
#endif /* CONFIG_PM */
/*
* Free a 0-order page
* cold == true ? free a cold page : free a hot page
*/
void free_hot_cold_page(struct page *page, bool cold)
{
struct zone *zone = page_zone(page);
struct per_cpu_pages *pcp;
unsigned long flags;
unsigned long pfn = page_to_pfn(page);
int migratetype;
if (!free_pages_prepare(page, 0))
return;
migratetype = get_pfnblock_migratetype(page, pfn);
set_pcppage_migratetype(page, migratetype);
local_irq_save(flags);
__count_vm_event(PGFREE);
/*
* We only track unmovable, reclaimable and movable on pcp lists.
* Free ISOLATE pages back to the allocator because they are being
* offlined but treat RESERVE as movable pages so we can get those
* areas back if necessary. Otherwise, we may have to free
* excessively into the page allocator
*/
if (migratetype >= MIGRATE_PCPTYPES) {
if (unlikely(is_migrate_isolate(migratetype))) {
free_one_page(zone, page, pfn, 0, migratetype);
goto out;
}
migratetype = MIGRATE_MOVABLE;
}
pcp = &this_cpu_ptr(zone->pageset)->pcp;
if (!cold)
list_add(&page->lru, &pcp->lists[migratetype]);
else
list_add_tail(&page->lru, &pcp->lists[migratetype]);
pcp->count++;
if (pcp->count >= pcp->high) {
unsigned long batch = READ_ONCE(pcp->batch);
free_pcppages_bulk(zone, batch, pcp);
pcp->count -= batch;
}
out:
local_irq_restore(flags);
}
/*
* Free a list of 0-order pages
*/
void free_hot_cold_page_list(struct list_head *list, bool cold)
{
struct page *page, *next;
list_for_each_entry_safe(page, next, list, lru) {
trace_mm_page_free_batched(page, cold);
free_hot_cold_page(page, cold);
}
}
/*
* 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;
gfp_t gfp_mask;
VM_BUG_ON_PAGE(PageCompound(page), page);
VM_BUG_ON_PAGE(!page_count(page), page);
#ifdef CONFIG_KMEMCHECK
/*
* Split shadow pages too, because free(page[0]) would
* otherwise free the whole shadow.
*/
if (kmemcheck_page_is_tracked(page))
split_page(virt_to_page(page[0].shadow), order);
#endif
gfp_mask = get_page_owner_gfp(page);
set_page_owner(page, 0, gfp_mask);
for (i = 1; i < (1 << order); i++) {
set_page_refcounted(page + i);
set_page_owner(page + i, 0, gfp_mask);
}
}
EXPORT_SYMBOL_GPL(split_page);
int __isolate_free_page(struct page *page, unsigned int order)
{
unsigned long watermark;
struct zone *zone;
int mt;
BUG_ON(!PageBuddy(page));
zone = page_zone(page);
mt = get_pageblock_migratetype(page);
if (!is_migrate_isolate(mt)) {
/* Obey watermarks as if the page was being allocated */
watermark = low_wmark_pages(zone) + (1 << order);
if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
return 0;
__mod_zone_freepage_state(zone, -(1UL << order), mt);
}
/* Remove page from free list */
list_del(&page->lru);
zone->free_area[order].nr_free--;
rmv_page_order(page);
set_page_owner(page, order, __GFP_MOVABLE);
/* Set the pageblock if the isolated page is at least a pageblock */
if (order >= pageblock_order - 1) {
struct page *endpage = page + (1 << order) - 1;
for (; page < endpage; page += pageblock_nr_pages) {
int mt = get_pageblock_migratetype(page);
if (!is_migrate_isolate(mt) && !is_migrate_cma(mt))
set_pageblock_migratetype(page,
MIGRATE_MOVABLE);
}
}
return 1UL << order;
}
/*
* Similar to split_page except the page is already free. As this is only
* being used for migration, the migratetype of the block also changes.
* As this is called with interrupts disabled, the caller is responsible
* for calling arch_alloc_page() and kernel_map_page() after interrupts
* are enabled.
*
* Note: this is probably too low level an operation for use in drivers.
* Please consult with lkml before using this in your driver.
*/
int split_free_page(struct page *page)
{
unsigned int order;
int nr_pages;
order = page_order(page);
nr_pages = __isolate_free_page(page, order);
if (!nr_pages)
return 0;
/* Split into individual pages */
set_page_refcounted(page);
split_page(page, order);
return nr_pages;
}
/*
* Allocate a page from the given zone. Use pcplists for order-0 allocations.
*/
static inline
struct page *buffered_rmqueue(struct zone *preferred_zone,
struct zone *zone, unsigned int order,
gfp_t gfp_flags, int alloc_flags, int migratetype)
{
unsigned long flags;
struct page *page;
bool cold = ((gfp_flags & __GFP_COLD) != 0);
if (likely(order == 0)) {
struct per_cpu_pages *pcp;
struct list_head *list;
local_irq_save(flags);
pcp = &this_cpu_ptr(zone->pageset)->pcp;
list = &pcp->lists[migratetype];
if (list_empty(list)) {
pcp->count += rmqueue_bulk(zone, 0,
pcp->batch, list,
migratetype, cold);
if (unlikely(list_empty(list)))
goto failed;
}
if (cold)
page = list_entry(list->prev, struct page, lru);
else
page = list_entry(list->next, struct page, lru);
list_del(&page->lru);
pcp->count--;
} else {
if (unlikely(gfp_flags & __GFP_NOFAIL)) {
/*
* __GFP_NOFAIL is not to be used in new code.
*
* All __GFP_NOFAIL callers should be fixed so that they
* properly detect and handle allocation failures.
*
* We most definitely don't want callers attempting to
* allocate greater than order-1 page units with
* __GFP_NOFAIL.
*/
WARN_ON_ONCE(order > 1);
}
spin_lock_irqsave(&zone->lock, flags);
page = NULL;
if (alloc_flags & ALLOC_HARDER) {
page = __rmqueue_smallest(zone, order, MIGRATE_HIGHATOMIC);
if (page)
trace_mm_page_alloc_zone_locked(page, order, migratetype);
}
if (!page)
page = __rmqueue(zone, order, migratetype, gfp_flags);
spin_unlock(&zone->lock);
if (!page)
goto failed;
__mod_zone_freepage_state(zone, -(1 << order),
get_pcppage_migratetype(page));
}
__mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order));
if (atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]) <= 0 &&
!test_bit(ZONE_FAIR_DEPLETED, &zone->flags))
set_bit(ZONE_FAIR_DEPLETED, &zone->flags);
__count_zone_vm_events(PGALLOC, zone, 1 << order);
zone_statistics(preferred_zone, zone, gfp_flags);
local_irq_restore(flags);
VM_BUG_ON_PAGE(bad_range(zone, page), page);
return page;
failed:
local_irq_restore(flags);
return NULL;
}
#ifdef CONFIG_FAIL_PAGE_ALLOC
static struct {
struct fault_attr attr;
bool ignore_gfp_highmem;
bool ignore_gfp_reclaim;
u32 min_order;
} fail_page_alloc = {
.attr = FAULT_ATTR_INITIALIZER,
.ignore_gfp_reclaim = true,
.ignore_gfp_highmem = true,
.min_order = 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 bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
if (order < fail_page_alloc.min_order)
return false;
if (gfp_mask & __GFP_NOFAIL)
return false;
if (fail_page_alloc.ignore_gfp_highmem && (gfp_mask & __GFP_HIGHMEM))
return false;
if (fail_page_alloc.ignore_gfp_reclaim &&
(gfp_mask & __GFP_DIRECT_RECLAIM))
return false;
return should_fail(&fail_page_alloc.attr, 1 << order);
}
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
static int __init fail_page_alloc_debugfs(void)
{
umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
struct dentry *dir;
dir = fault_create_debugfs_attr("fail_page_alloc", NULL,
&fail_page_alloc.attr);
if (IS_ERR(dir))
return PTR_ERR(dir);
if (!debugfs_create_bool("ignore-gfp-wait", mode, dir,
&fail_page_alloc.ignore_gfp_reclaim))
goto fail;
if (!debugfs_create_bool("ignore-gfp-highmem", mode, dir,
&fail_page_alloc.ignore_gfp_highmem))
goto fail;
if (!debugfs_create_u32("min-order", mode, dir,
&fail_page_alloc.min_order))
goto fail;
return 0;
fail:
debugfs_remove_recursive(dir);
return -ENOMEM;
}
late_initcall(fail_page_alloc_debugfs);
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
#else /* CONFIG_FAIL_PAGE_ALLOC */
static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
return false;
}
#endif /* CONFIG_FAIL_PAGE_ALLOC */
/*
* Return true if free base pages are above 'mark'. For high-order checks it
* will return true of the order-0 watermark is reached and there is at least
* one free page of a suitable size. Checking now avoids taking the zone lock
* to check in the allocation paths if no pages are free.
*/
static bool __zone_watermark_ok(struct zone *z, unsigned int order,
unsigned long mark, int classzone_idx, int alloc_flags,
long free_pages)
{
long min = mark;
int o;
const int alloc_harder = (alloc_flags & ALLOC_HARDER);
/* free_pages may go negative - that's OK */
free_pages -= (1 << order) - 1;
if (alloc_flags & ALLOC_HIGH)
min -= min / 2;
/*
* If the caller does not have rights to ALLOC_HARDER then subtract
* the high-atomic reserves. This will over-estimate the size of the
* atomic reserve but it avoids a search.
*/
if (likely(!alloc_harder))
free_pages -= z->nr_reserved_highatomic;
else
min -= min / 4;
#ifdef CONFIG_CMA
/* If allocation can't use CMA areas don't use free CMA pages */
if (!(alloc_flags & ALLOC_CMA))
free_pages -= zone_page_state(z, NR_FREE_CMA_PAGES);
#endif
/*
* Check watermarks for an order-0 allocation request. If these
* are not met, then a high-order request also cannot go ahead
* even if a suitable page happened to be free.
*/
if (free_pages <= min + z->lowmem_reserve[classzone_idx])
return false;
/* If this is an order-0 request then the watermark is fine */
if (!order)
return true;
/* For a high-order request, check at least one suitable page is free */
for (o = order; o < MAX_ORDER; o++) {
struct free_area *area = &z->free_area[o];
int mt;
if (!area->nr_free)
continue;
if (alloc_harder)
return true;
for (mt = 0; mt < MIGRATE_PCPTYPES; mt++) {
if (!list_empty(&area->free_list[mt]))
return true;
}
#ifdef CONFIG_CMA
if ((alloc_flags & ALLOC_CMA) &&
!list_empty(&area->free_list[MIGRATE_CMA])) {
return true;
}
#endif
}
return false;
}
bool zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
int classzone_idx, int alloc_flags)
{
return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags,
zone_page_state(z, NR_FREE_PAGES));
}
bool zone_watermark_ok_safe(struct zone *z, unsigned int order,
unsigned long mark, int classzone_idx)
{
long free_pages = zone_page_state(z, NR_FREE_PAGES);
if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark)
free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES);
return __zone_watermark_ok(z, order, mark, classzone_idx, 0,
free_pages);
}
#ifdef CONFIG_NUMA
static bool zone_local(struct zone *local_zone, struct zone *zone)
{
return local_zone->node == zone->node;
}
static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
{
return node_distance(zone_to_nid(local_zone), zone_to_nid(zone)) <
RECLAIM_DISTANCE;
}
#else /* CONFIG_NUMA */
static bool zone_local(struct zone *local_zone, struct zone *zone)
{
return true;
}
static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone)
{
return true;
}
#endif /* CONFIG_NUMA */
static void reset_alloc_batches(struct zone *preferred_zone)
{
struct zone *zone = preferred_zone->zone_pgdat->node_zones;
do {
mod_zone_page_state(zone, NR_ALLOC_BATCH,
high_wmark_pages(zone) - low_wmark_pages(zone) -
atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]));
clear_bit(ZONE_FAIR_DEPLETED, &zone->flags);
} while (zone++ != preferred_zone);
}
/*
* 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, int alloc_flags,
const struct alloc_context *ac)
{
struct zonelist *zonelist = ac->zonelist;
struct zoneref *z;
struct page *page = NULL;
struct zone *zone;
int nr_fair_skipped = 0;
bool zonelist_rescan;
zonelist_scan:
zonelist_rescan = false;
/*
* Scan zonelist, looking for a zone with enough free.
* See also __cpuset_node_allowed() comment in kernel/cpuset.c.
*/
for_each_zone_zonelist_nodemask(zone, z, zonelist, ac->high_zoneidx,
ac->nodemask) {
unsigned long mark;
if (cpusets_enabled() &&
(alloc_flags & ALLOC_CPUSET) &&
!cpuset_zone_allowed(zone, gfp_mask))
continue;
/*
* Distribute pages in proportion to the individual
* zone size to ensure fair page aging. The zone a
* page was allocated in should have no effect on the
* time the page has in memory before being reclaimed.
*/
if (alloc_flags & ALLOC_FAIR) {
if (!zone_local(ac->preferred_zone, zone))
break;
if (test_bit(ZONE_FAIR_DEPLETED, &zone->flags)) {
nr_fair_skipped++;
continue;
}
}
/*
* When allocating a page cache page for writing, we
* want to get it from a zone that is within its dirty
* limit, such that no single zone holds more than its
* proportional share of globally allowed dirty pages.
* The dirty limits take into account the zone's
* lowmem reserves and high watermark so that kswapd
* should be able to balance it without having to
* write pages from its LRU list.
*
* This may look like it could increase pressure on
* lower zones by failing allocations in higher zones
* before they are full. But the pages that do spill
* over are limited as the lower zones are protected
* by this very same mechanism. It should not become
* a practical burden to them.
*
* XXX: For now, allow allocations to potentially
* exceed the per-zone dirty limit in the slowpath
* (spread_dirty_pages unset) before going into reclaim,
* which is important when on a NUMA setup the allowed
* zones are together not big enough to reach the
* global limit. The proper fix for these situations
* will require awareness of zones in the
* dirty-throttling and the flusher threads.
*/
if (ac->spread_dirty_pages && !zone_dirty_ok(zone))
continue;
mark = zone->watermark[alloc_flags & ALLOC_WMARK_MASK];
if (!zone_watermark_ok(zone, order, mark,
ac->classzone_idx, alloc_flags)) {
int ret;
/* Checked here to keep the fast path fast */
BUILD_BUG_ON(ALLOC_NO_WATERMARKS < NR_WMARK);
if (alloc_flags & ALLOC_NO_WATERMARKS)
goto try_this_zone;
if (zone_reclaim_mode == 0 ||
!zone_allows_reclaim(ac->preferred_zone, zone))
continue;
ret = zone_reclaim(zone, gfp_mask, order);
switch (ret) {
case ZONE_RECLAIM_NOSCAN:
/* did not scan */
continue;
case ZONE_RECLAIM_FULL:
/* scanned but unreclaimable */
continue;
default:
/* did we reclaim enough */
if (zone_watermark_ok(zone, order, mark,
ac->classzone_idx, alloc_flags))
goto try_this_zone;
continue;
}
}
try_this_zone:
page = buffered_rmqueue(ac->preferred_zone, zone, order,
gfp_mask, alloc_flags, ac->migratetype);
if (page) {
if (prep_new_page(page, order, gfp_mask, alloc_flags))
goto try_this_zone;
/*
* If this is a high-order atomic allocation then check
* if the pageblock should be reserved for the future
*/
if (unlikely(order && (alloc_flags & ALLOC_HARDER)))
reserve_highatomic_pageblock(page, zone, order);
return page;
}
}
/*
* The first pass makes sure allocations are spread fairly within the
* local node. However, the local node might have free pages left
* after the fairness batches are exhausted, and remote zones haven't
* even been considered yet. Try once more without fairness, and
* include remote zones now, before entering the slowpath and waking
* kswapd: prefer spilling to a remote zone over swapping locally.
*/
if (alloc_flags & ALLOC_FAIR) {
alloc_flags &= ~ALLOC_FAIR;
if (nr_fair_skipped) {
zonelist_rescan = true;
reset_alloc_batches(ac->preferred_zone);
}
if (nr_online_nodes > 1)
zonelist_rescan = true;
}
if (zonelist_rescan)
goto zonelist_scan;
return NULL;
}
/*
* Large machines with many possible nodes should not always dump per-node
* meminfo in irq context.
*/
static inline bool should_suppress_show_mem(void)
{
bool ret = false;
#if NODES_SHIFT > 8
ret = in_interrupt();
#endif
return ret;
}
static DEFINE_RATELIMIT_STATE(nopage_rs,
DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);
void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...)
{
unsigned int filter = SHOW_MEM_FILTER_NODES;
if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs) ||
debug_guardpage_minorder() > 0)
return;
/*
* This documents exceptions given to allocations in certain
* contexts that are allowed to allocate outside current's set
* of allowed nodes.
*/
if (!(gfp_mask & __GFP_NOMEMALLOC))
if (test_thread_flag(TIF_MEMDIE) ||
(current->flags & (PF_MEMALLOC | PF_EXITING)))
filter &= ~SHOW_MEM_FILTER_NODES;
if (in_interrupt() || !(gfp_mask & __GFP_DIRECT_RECLAIM))
filter &= ~SHOW_MEM_FILTER_NODES;
if (fmt) {
struct va_format vaf;
va_list args;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
pr_warn("%pV", &vaf);
va_end(args);
}
pr_warn("%s: page allocation failure: order:%d, mode:0x%x\n",
current->comm, order, gfp_mask);
dump_stack();
if (!should_suppress_show_mem())
show_mem(filter);
}
static inline struct page *
__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
const struct alloc_context *ac, unsigned long *did_some_progress)
{
struct oom_control oc = {
.zonelist = ac->zonelist,
.nodemask = ac->nodemask,
.gfp_mask = gfp_mask,
.order = order,
};
struct page *page;
*did_some_progress = 0;
/*
* Acquire the oom lock. If that fails, somebody else is
* making progress for us.
*/
if (!mutex_trylock(&oom_lock)) {
*did_some_progress = 1;
schedule_timeout_uninterruptible(1);
return NULL;
}
/*
* 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,
ALLOC_WMARK_HIGH|ALLOC_CPUSET, ac);
if (page)
goto out;
if (!(gfp_mask & __GFP_NOFAIL)) {
/* Coredumps can quickly deplete all memory reserves */
if (current->flags & PF_DUMPCORE)
goto out;
/* The OOM killer will not help higher order allocs */
if (order > PAGE_ALLOC_COSTLY_ORDER)
goto out;
/* The OOM killer does not needlessly kill tasks for lowmem */
if (ac->high_zoneidx < ZONE_NORMAL)
goto out;
/* The OOM killer does not compensate for IO-less reclaim */
if (!(gfp_mask & __GFP_FS)) {
/*
* XXX: Page reclaim didn't yield anything,
* and the OOM killer can't be invoked, but
* keep looping as per tradition.
*/
*did_some_progress = 1;
goto out;
}
if (pm_suspended_storage())
goto out;
/* The OOM killer may not free memory on a specific node */
if (gfp_mask & __GFP_THISNODE)
goto out;
}
/* Exhausted what can be done so it's blamo time */
if (out_of_memory(&oc) || WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL))
*did_some_progress = 1;
out:
mutex_unlock(&oom_lock);
return page;
}
#ifdef CONFIG_COMPACTION
/* Try memory compaction for high-order allocations before reclaim */
static struct page *
__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
int alloc_flags, const struct alloc_context *ac,
enum migrate_mode mode, int *contended_compaction,
bool *deferred_compaction)
{
unsigned long compact_result;
struct page *page;
if (!order)
return NULL;
current->flags |= PF_MEMALLOC;
compact_result = try_to_compact_pages(gfp_mask, order, alloc_flags, ac,
mode, contended_compaction);
current->flags &= ~PF_MEMALLOC;
switch (compact_result) {
case COMPACT_DEFERRED:
*deferred_compaction = true;
/* fall-through */
case COMPACT_SKIPPED:
return NULL;
default:
break;
}
/*
* At least in one zone compaction wasn't deferred or skipped, so let's
* count a compaction stall
*/
count_vm_event(COMPACTSTALL);
page = get_page_from_freelist(gfp_mask, order,
alloc_flags & ~ALLOC_NO_WATERMARKS, ac);
if (page) {
struct zone *zone = page_zone(page);
zone->compact_blockskip_flush = false;
compaction_defer_reset(zone, order, true);
count_vm_event(COMPACTSUCCESS);
return page;
}
/*
* It's bad if compaction run occurs and fails. The most likely reason
* is that pages exist, but not enough to satisfy watermarks.
*/
count_vm_event(COMPACTFAIL);
cond_resched();
return NULL;
}
#else
static inline struct page *
__alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
int alloc_flags, const struct alloc_context *ac,
enum migrate_mode mode, int *contended_compaction,
bool *deferred_compaction)
{
return NULL;
}
#endif /* CONFIG_COMPACTION */
/* Perform direct synchronous page reclaim */
static int
__perform_reclaim(gfp_t gfp_mask, unsigned int order,
const struct alloc_context *ac)
{
struct reclaim_state reclaim_state;
int progress;
cond_resched();
/* We now go into synchronous reclaim */
cpuset_memory_pressure_bump();
current->flags |= PF_MEMALLOC;
lockdep_set_current_reclaim_state(gfp_mask);
reclaim_state.reclaimed_slab = 0;
current->reclaim_state = &reclaim_state;
progress = try_to_free_pages(ac->zonelist, order, gfp_mask,
ac->nodemask);
current->reclaim_state = NULL;
lockdep_clear_current_reclaim_state();
current->flags &= ~PF_MEMALLOC;
cond_resched();
return progress;
}
/* The really slow allocator path where we enter direct reclaim */
static inline struct page *
__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
int alloc_flags, const struct alloc_context *ac,
unsigned long *did_some_progress)
{
struct page *page = NULL;
bool drained = false;
*did_some_progress = __perform_reclaim(gfp_mask, order, ac);
if (unlikely(!(*did_some_progress)))
return NULL;
retry:
page = get_page_from_freelist(gfp_mask, order,
alloc_flags & ~ALLOC_NO_WATERMARKS, ac);
/*
* If an allocation failed after direct reclaim, it could be because
* pages are pinned on the per-cpu lists or in high alloc reserves.
* Shrink them them and try again
*/
if (!page && !drained) {
unreserve_highatomic_pageblock(ac);
drain_all_pages(NULL);
drained = true;
goto retry;
}
return page;
}
/*
* This is called in the allocator slow-path if the allocation request is of
* sufficient urgency to ignore watermarks and take other desperate measures
*/
static inline struct page *
__alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
const struct alloc_context *ac)
{
struct page *page;
do {
page = get_page_from_freelist(gfp_mask, order,
ALLOC_NO_WATERMARKS, ac);
if (!page && gfp_mask & __GFP_NOFAIL)
wait_iff_congested(ac->preferred_zone, BLK_RW_ASYNC,
HZ/50);
} while (!page && (gfp_mask & __GFP_NOFAIL));
return page;
}
static void wake_all_kswapds(unsigned int order, const struct alloc_context *ac)
{
struct zoneref *z;
struct zone *zone;
for_each_zone_zonelist_nodemask(zone, z, ac->zonelist,
ac->high_zoneidx, ac->nodemask)
wakeup_kswapd(zone, order, zone_idx(ac->preferred_zone));
}
static inline int
gfp_to_alloc_flags(gfp_t gfp_mask)
{
int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
/* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
/*
* 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 (__GFP_ATOMIC) and ALLOC_HIGH (__GFP_HIGH).
*/
alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
if (gfp_mask & __GFP_ATOMIC) {
/*
* Not worth trying to allocate harder for __GFP_NOMEMALLOC even
* if it can't schedule.
*/
if (!(gfp_mask & __GFP_NOMEMALLOC))
alloc_flags |= ALLOC_HARDER;
/*
* Ignore cpuset mems for GFP_ATOMIC rather than fail, see the
* comment for __cpuset_node_allowed().
*/
alloc_flags &= ~ALLOC_CPUSET;
} else if (unlikely(rt_task(current)) && !in_interrupt())
alloc_flags |= ALLOC_HARDER;
if (likely(!(gfp_mask & __GFP_NOMEMALLOC))) {
if (gfp_mask & __GFP_MEMALLOC)
alloc_flags |= ALLOC_NO_WATERMARKS;
else if (in_serving_softirq() && (current->flags & PF_MEMALLOC))
alloc_flags |= ALLOC_NO_WATERMARKS;
else if (!in_interrupt() &&
((current->flags & PF_MEMALLOC) ||
unlikely(test_thread_flag(TIF_MEMDIE))))
alloc_flags |= ALLOC_NO_WATERMARKS;
}
#ifdef CONFIG_CMA
if (gfpflags_to_migratetype(gfp_mask) == MIGRATE_MOVABLE)
alloc_flags |= ALLOC_CMA;
#endif
return alloc_flags;
}
bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
{
return !!(gfp_to_alloc_flags(gfp_mask) & ALLOC_NO_WATERMARKS);
}
static inline bool is_thp_gfp_mask(gfp_t gfp_mask)
{
return (gfp_mask & (GFP_TRANSHUGE | __GFP_KSWAPD_RECLAIM)) == GFP_TRANSHUGE;
}
static inline struct page *
__alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
struct alloc_context *ac)
{
bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM;
struct page *page = NULL;
int alloc_flags;
unsigned long pages_reclaimed = 0;
unsigned long did_some_progress;
enum migrate_mode migration_mode = MIGRATE_ASYNC;
bool deferred_compaction = false;
int contended_compaction = COMPACT_CONTENDED_NONE;
/*
* In the slowpath, we sanity check order to avoid ever trying to
* reclaim >= MAX_ORDER areas which will never succeed. Callers may
* be using allocators in order of preference for an area that is
* too large.
*/
if (order >= MAX_ORDER) {
WARN_ON_ONCE(!(gfp_mask & __GFP_NOWARN));
return NULL;
}
/*
* We also sanity check to catch abuse of atomic reserves being used by
* callers that are not in atomic context.
*/
if (WARN_ON_ONCE((gfp_mask & (__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)) ==
(__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
gfp_mask &= ~__GFP_ATOMIC;
/*
* If this allocation cannot block and it is for a specific node, then
* fail early. There's no need to wakeup kswapd or retry for a
* speculative node-specific allocation.
*/
if (IS_ENABLED(CONFIG_NUMA) && (gfp_mask & __GFP_THISNODE) && !can_direct_reclaim)
goto nopage;
retry:
if (gfp_mask & __GFP_KSWAPD_RECLAIM)
wake_all_kswapds(order, ac);
/*
* 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.
*/
alloc_flags = gfp_to_alloc_flags(gfp_mask);
/*
* Find the true preferred zone if the allocation is unconstrained by
* cpusets.
*/
if (!(alloc_flags & ALLOC_CPUSET) && !ac->nodemask) {
struct zoneref *preferred_zoneref;
preferred_zoneref = first_zones_zonelist(ac->zonelist,
ac->high_zoneidx, NULL, &ac->preferred_zone);
ac->classzone_idx = zonelist_zone_idx(preferred_zoneref);
}
/* This is the last chance, in general, before the goto nopage. */
page = get_page_from_freelist(gfp_mask, order,
alloc_flags & ~ALLOC_NO_WATERMARKS, ac);
if (page)
goto got_pg;
/* Allocate without watermarks if the context allows */
if (alloc_flags & ALLOC_NO_WATERMARKS) {
/*
* Ignore mempolicies if ALLOC_NO_WATERMARKS on the grounds
* the allocation is high priority and these type of
* allocations are system rather than user orientated
*/
ac->zonelist = node_zonelist(numa_node_id(), gfp_mask);
page = __alloc_pages_high_priority(gfp_mask, order, ac);
if (page) {
goto got_pg;
}
}
/* Caller is not willing to reclaim, we can't balance anything */
if (!can_direct_reclaim) {
/*
* All existing users of the deprecated __GFP_NOFAIL are
* blockable, so warn of any new users that actually allow this
* type of allocation to fail.
*/
WARN_ON_ONCE(gfp_mask & __GFP_NOFAIL);
goto nopage;
}
/* Avoid recursion of direct reclaim */
if (current->flags & PF_MEMALLOC)
goto nopage;
/* Avoid allocations with no watermarks from looping endlessly */
if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL))
goto nopage;
/*
* Try direct compaction. The first pass is asynchronous. Subsequent
* attempts after direct reclaim are synchronous
*/
page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags, ac,
migration_mode,
&contended_compaction,
&deferred_compaction);
if (page)
goto got_pg;
/* Checks for THP-specific high-order allocations */
if (is_thp_gfp_mask(gfp_mask)) {
/*
* If compaction is deferred for high-order allocations, it is
* because sync compaction recently failed. If this is the case
* and the caller requested a THP allocation, we do not want
* to heavily disrupt the system, so we fail the allocation
* instead of entering direct reclaim.
*/
if (deferred_compaction)
goto nopage;
/*
* In all zones where compaction was attempted (and not
* deferred or skipped), lock contention has been detected.
* For THP allocation we do not want to disrupt the others
* so we fallback to base pages instead.
*/
if (contended_compaction == COMPACT_CONTENDED_LOCK)
goto nopage;
/*
* If compaction was aborted due to need_resched(), we do not
* want to further increase allocation latency, unless it is
* khugepaged trying to collapse.
*/
if (contended_compaction == COMPACT_CONTENDED_SCHED
&& !(current->flags & PF_KTHREAD))
goto nopage;
}
/*
* It can become very expensive to allocate transparent hugepages at
* fault, so use asynchronous memory compaction for THP unless it is
* khugepaged trying to collapse.
*/
if (!is_thp_gfp_mask(gfp_mask) || (current->flags & PF_KTHREAD))
migration_mode = MIGRATE_SYNC_LIGHT;
/* Try direct reclaim and then allocating */
page = __alloc_pages_direct_reclaim(gfp_mask, order, alloc_flags, ac,
&did_some_progress);
if (page)
goto got_pg;
/* Do not loop if specifically requested */
if (gfp_mask & __GFP_NORETRY)
goto noretry;
/* Keep reclaiming pages as long as there is reasonable progress */
pages_reclaimed += did_some_progress;
if ((did_some_progress && order <= PAGE_ALLOC_COSTLY_ORDER) ||
((gfp_mask & __GFP_REPEAT) && pages_reclaimed < (1 << order))) {
/* Wait for some write requests to complete then retry */
wait_iff_congested(ac->preferred_zone, BLK_RW_ASYNC, HZ/50);
goto retry;
}
/* Reclaim has failed us, start killing things */
page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
if (page)
goto got_pg;
/* Retry as long as the OOM killer is making progress */
if (did_some_progress)
goto retry;
noretry:
/*
* High-order allocations do not necessarily loop after
* direct reclaim and reclaim/compaction depends on compaction
* being called after reclaim so call directly if necessary
*/
page = __alloc_pages_direct_compact(gfp_mask, order, alloc_flags,
ac, migration_mode,
&contended_compaction,
&deferred_compaction);
if (page)
goto got_pg;
nopage:
warn_alloc_failed(gfp_mask, order, NULL);
got_pg:
return page;
}
/*
* This is the 'heart' of the zoned buddy allocator.
*/
struct page *
__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, nodemask_t *nodemask)
{
struct zoneref *preferred_zoneref;
struct page *page = NULL;
unsigned int cpuset_mems_cookie;
int alloc_flags = ALLOC_WMARK_LOW|ALLOC_CPUSET|ALLOC_FAIR;
gfp_t alloc_mask; /* The gfp_t that was actually used for allocation */
struct alloc_context ac = {
.high_zoneidx = gfp_zone(gfp_mask),
.nodemask = nodemask,
.migratetype = gfpflags_to_migratetype(gfp_mask),
};
gfp_mask &= gfp_allowed_mask;
lockdep_trace_alloc(gfp_mask);
might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
if (should_fail_alloc_page(gfp_mask, order))
return NULL;
/*
* Check the zones suitable for the gfp_mask contain at least one
* valid zone. It's possible to have an empty zonelist as a result
* of __GFP_THISNODE and a memoryless node
*/
if (unlikely(!zonelist->_zonerefs->zone))
return NULL;
if (IS_ENABLED(CONFIG_CMA) && ac.migratetype == MIGRATE_MOVABLE)
alloc_flags |= ALLOC_CMA;
retry_cpuset:
cpuset_mems_cookie = read_mems_allowed_begin();
/* We set it here, as __alloc_pages_slowpath might have changed it */
ac.zonelist = zonelist;
/* Dirty zone balancing only done in the fast path */
ac.spread_dirty_pages = (gfp_mask & __GFP_WRITE);
/* The preferred zone is used for statistics later */
preferred_zoneref = first_zones_zonelist(ac.zonelist, ac.high_zoneidx,
ac.nodemask ? : &cpuset_current_mems_allowed,
&ac.preferred_zone);
if (!ac.preferred_zone)
goto out;
ac.classzone_idx = zonelist_zone_idx(preferred_zoneref);
/* First allocation attempt */
alloc_mask = gfp_mask|__GFP_HARDWALL;
page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac);
if (unlikely(!page)) {
/*
* Runtime PM, block IO and its error handling path
* can deadlock because I/O on the device might not
* complete.
*/
alloc_mask = memalloc_noio_flags(gfp_mask);
ac.spread_dirty_pages = false;
page = __alloc_pages_slowpath(alloc_mask, order, &ac);
}
if (kmemcheck_enabled && page)
kmemcheck_pagealloc_alloc(page, order, gfp_mask);
trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype);
out:
/*
* When updating a task's mems_allowed, it is possible to race with
* parallel threads in such a way that an allocation can fail while
* the mask is being updated. If a page allocation is about to fail,
* check if the cpuset changed during allocation and if so, retry.
*/
if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
goto retry_cpuset;
return page;
}
EXPORT_SYMBOL(__alloc_pages_nodemask);
/*
* Common helper functions.
*/
unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order)
{
struct page *page;
/*
* __get_free_pages() returns a 32-bit address, which cannot represent
* a highmem page
*/
VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0);
page = alloc_pages(gfp_mask, order);
if (!page)
return 0;
return (unsigned long) page_address(page);
}
EXPORT_SYMBOL(__get_free_pages);
unsigned long get_zeroed_page(gfp_t gfp_mask)
{
return __get_free_pages(gfp_mask | __GFP_ZERO, 0);
}
EXPORT_SYMBOL(get_zeroed_page);
void __free_pages(struct page *page, unsigned int order)
{
if (put_page_testzero(page)) {
if (order == 0)
free_hot_cold_page(page, false);
else
__free_pages_ok(page, order);
}
}
EXPORT_SYMBOL(__free_pages);
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);
/*
* Page Fragment:
* An arbitrary-length arbitrary-offset area of memory which resides
* within a 0 or higher order page. Multiple fragments within that page
* are individually refcounted, in the page's reference counter.
*
* The page_frag functions below provide a simple allocation framework for
* page fragments. This is used by the network stack and network device
* drivers to provide a backing region of memory for use as either an
* sk_buff->head, or to be used in the "frags" portion of skb_shared_info.
*/
static struct page *__page_frag_refill(struct page_frag_cache *nc,
gfp_t gfp_mask)
{
struct page *page = NULL;
gfp_t gfp = gfp_mask;
#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
gfp_mask |= __GFP_COMP | __GFP_NOWARN | __GFP_NORETRY |
__GFP_NOMEMALLOC;
page = alloc_pages_node(NUMA_NO_NODE, gfp_mask,
PAGE_FRAG_CACHE_MAX_ORDER);
nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE;
#endif
if (unlikely(!page))
page = alloc_pages_node(NUMA_NO_NODE, gfp, 0);
nc->va = page ? page_address(page) : NULL;
return page;
}
void *__alloc_page_frag(struct page_frag_cache *nc,
unsigned int fragsz, gfp_t gfp_mask)
{
unsigned int size = PAGE_SIZE;
struct page *page;
int offset;
if (unlikely(!nc->va)) {
refill:
page = __page_frag_refill(nc, gfp_mask);
if (!page)
return NULL;
#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
/* if size can vary use size else just use PAGE_SIZE */
size = nc->size;
#endif
/* Even if we own the page, we do not use atomic_set().
* This would break get_page_unless_zero() users.
*/
atomic_add(size - 1, &page->_count);
/* reset page count bias and offset to start of new frag */
nc->pfmemalloc = page_is_pfmemalloc(page);
nc->pagecnt_bias = size;
nc->offset = size;
}
offset = nc->offset - fragsz;
if (unlikely(offset < 0)) {
page = virt_to_page(nc->va);
if (!atomic_sub_and_test(nc->pagecnt_bias, &page->_count))
goto refill;
#if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
/* if size can vary use size else just use PAGE_SIZE */
size = nc->size;
#endif
/* OK, page count is 0, we can safely set it */
atomic_set(&page->_count, size);
/* reset page count bias and offset to start of new frag */
nc->pagecnt_bias = size;
offset = size - fragsz;
}
nc->pagecnt_bias--;
nc->offset = offset;
return nc->va + offset;
}
EXPORT_SYMBOL(__alloc_page_frag);
/*
* Frees a page fragment allocated out of either a compound or order 0 page.
*/
void __free_page_frag(void *addr)
{
struct page *page = virt_to_head_page(addr);
if (unlikely(put_page_testzero(page)))
__free_pages_ok(page, compound_order(page));
}
EXPORT_SYMBOL(__free_page_frag);
/*
* alloc_kmem_pages charges newly allocated pages to the kmem resource counter
* of the current memory cgroup.
*
* It should be used when the caller would like to use kmalloc, but since the
* allocation is large, it has to fall back to the page allocator.
*/
struct page *alloc_kmem_pages(gfp_t gfp_mask, unsigned int order)
{
struct page *page;
page = alloc_pages(gfp_mask, order);
if (page && memcg_kmem_charge(page, gfp_mask, order) != 0) {
__free_pages(page, order);
page = NULL;
}
return page;
}
struct page *alloc_kmem_pages_node(int nid, gfp_t gfp_mask, unsigned int order)
{
struct page *page;
page = alloc_pages_node(nid, gfp_mask, order);
if (page && memcg_kmem_charge(page, gfp_mask, order) != 0) {
__free_pages(page, order);
page = NULL;
}
return page;
}
/*
* __free_kmem_pages and free_kmem_pages will free pages allocated with
* alloc_kmem_pages.
*/
void __free_kmem_pages(struct page *page, unsigned int order)
{
memcg_kmem_uncharge(page, order);
__free_pages(page, order);
}
void free_kmem_pages(unsigned long addr, unsigned int order)
{
if (addr != 0) {
VM_BUG_ON(!virt_addr_valid((void *)addr));
__free_kmem_pages(virt_to_page((void *)addr), order);
}
}
static void *make_alloc_exact(unsigned long addr, unsigned order, size_t size)
{
if (addr) {
unsigned long alloc_end = addr + (PAGE_SIZE << order);
unsigned long used = addr + PAGE_ALIGN(size);
split_page(virt_to_page((void *)addr), order);
while (used < alloc_end) {
free_page(used);
used += PAGE_SIZE;
}
}
return (void *)addr;
}
/**
* alloc_pages_exact - allocate an exact number physically-contiguous pages.
* @size: the number of bytes to allocate
* @gfp_mask: GFP flags for the allocation
*
* This function is similar to alloc_pages(), except that it allocates the
* minimum number of pages to satisfy the request. alloc_pages() can only
* allocate memory in power-of-two pages.
*
* This function is also limited by MAX_ORDER.
*
* Memory allocated by this function must be released by free_pages_exact().
*/
void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
{
unsigned int order = get_order(size);
unsigned long addr;
addr = __get_free_pages(gfp_mask, order);
return make_alloc_exact(addr, order, size);
}
EXPORT_SYMBOL(alloc_pages_exact);
/**
* alloc_pages_exact_nid - allocate an exact number of physically-contiguous
* pages on a node.
* @nid: the preferred node ID where memory should be allocated
* @size: the number of bytes to allocate
* @gfp_mask: GFP flags for the allocation
*
* Like alloc_pages_exact(), but try to allocate on node nid first before falling
* back.
*/
void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
{
unsigned order = get_order(size);
struct page *p = alloc_pages_node(nid, gfp_mask, order);
if (!p)
return NULL;
return make_alloc_exact((unsigned long)page_address(p), order, size);
}
/**
* free_pages_exact - release memory allocated via alloc_pages_exact()
* @virt: the value returned by alloc_pages_exact.
* @size: size of allocation, same value as passed to alloc_pages_exact().
*
* Release the memory allocated by a previous call to alloc_pages_exact.
*/
void free_pages_exact(void *virt, size_t size)
{
unsigned long addr = (unsigned long)virt;
unsigned long end = addr + PAGE_ALIGN(size);
while (addr < end) {
free_page(addr);
addr += PAGE_SIZE;
}
}
EXPORT_SYMBOL(free_pages_exact);
/**
* nr_free_zone_pages - count number of pages beyond high watermark
* @offset: The zone index of the highest zone
*
* nr_free_zone_pages() counts the number of counts pages which are beyond the
* high watermark within all zones at or below a given zone index. For each
* zone, the number of pages is calculated as:
* managed_pages - high_pages
*/
static unsigned long nr_free_zone_pages(int offset)
{
struct zoneref *z;
struct zone *zone;
/* Just pick one node, since fallback list is circular */
unsigned long sum = 0;
struct zonelist *zonelist = node_zonelist(numa_node_id(), GFP_KERNEL);
for_each_zone_zonelist(zone, z, zonelist, offset) {
unsigned long size = zone->managed_pages;
unsigned long high = high_wmark_pages(zone);
if (size > high)
sum += size - high;
}
return sum;
}
/**
* nr_free_buffer_pages - count number of pages beyond high watermark
*
* nr_free_buffer_pages() counts the number of pages which are beyond the high
* watermark within ZONE_DMA and ZONE_NORMAL.
*/
unsigned long nr_free_buffer_pages(void)
{
return nr_free_zone_pages(gfp_zone(GFP_USER));
}
EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
/**
* nr_free_pagecache_pages - count number of pages beyond high watermark
*
* nr_free_pagecache_pages() counts the number of pages which are beyond the
* high watermark within all zones.
*/
unsigned long nr_free_pagecache_pages(void)
{
return nr_free_zone_pages(gfp_zone(GFP_HIGHUSER_MOVABLE));
}
static inline void show_node(struct zone *zone)
{
if (IS_ENABLED(CONFIG_NUMA))
printk("Node %d ", zone_to_nid(zone));
}
void si_meminfo(struct sysinfo *val)
{
val->totalram = totalram_pages;
val->sharedram = global_page_state(NR_SHMEM);
val->freeram = global_page_state(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)
{
int zone_type; /* needs to be signed */
unsigned long managed_pages = 0;
pg_data_t *pgdat = NODE_DATA(nid);
for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++)
managed_pages += pgdat->node_zones[zone_type].managed_pages;
val->totalram = managed_pages;
val->sharedram = node_page_state(nid, NR_SHMEM);
val->freeram = node_page_state(nid, NR_FREE_PAGES);
#ifdef CONFIG_HIGHMEM
val->totalhigh = pgdat->node_zones[ZONE_HIGHMEM].managed_pages;
val->freehigh = zone_page_state(&pgdat->node_zones[ZONE_HIGHMEM],
NR_FREE_PAGES);
#else
val->totalhigh = 0;
val->freehigh = 0;
#endif
val->mem_unit = PAGE_SIZE;
}
#endif
/*
* Determine whether the node should be displayed or not, depending on whether
* SHOW_MEM_FILTER_NODES was passed to show_free_areas().
*/
bool skip_free_areas_node(unsigned int flags, int nid)
{
bool ret = false;
unsigned int cpuset_mems_cookie;
if (!(flags & SHOW_MEM_FILTER_NODES))
goto out;
do {
cpuset_mems_cookie = read_mems_allowed_begin();
ret = !node_isset(nid, cpuset_current_mems_allowed);
} while (read_mems_allowed_retry(cpuset_mems_cookie));
out:
return ret;
}
#define K(x) ((x) << (PAGE_SHIFT-10))
static void show_migration_types(unsigned char type)
{
static const char types[MIGRATE_TYPES] = {
[MIGRATE_UNMOVABLE] = 'U',
[MIGRATE_RECLAIMABLE] = 'E',
[MIGRATE_MOVABLE] = 'M',
#ifdef CONFIG_CMA
[MIGRATE_CMA] = 'C',
#endif
#ifdef CONFIG_MEMORY_ISOLATION
[MIGRATE_ISOLATE] = 'I',
#endif
};
char tmp[MIGRATE_TYPES + 1];
char *p = tmp;
int i;
for (i = 0; i < MIGRATE_TYPES; i++) {
if (type & (1 << i))
*p++ = types[i];
}
*p = '\0';
printk("(%s) ", tmp);
}
/*
* 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.
*
* Bits in @filter:
* SHOW_MEM_FILTER_NODES: suppress nodes that are not allowed by current's
* cpuset.
*/
void show_free_areas(unsigned int filter)
{
unsigned long free_pcp = 0;
int cpu;
struct zone *zone;
for_each_populated_zone(zone) {
if (skip_free_areas_node(filter, zone_to_nid(zone)))
continue;
for_each_online_cpu(cpu)
free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
}
printk("active_anon:%lu inactive_anon:%lu isolated_anon:%lu\n"
" active_file:%lu inactive_file:%lu isolated_file:%lu\n"
" unevictable:%lu dirty:%lu writeback:%lu unstable:%lu\n"
" slab_reclaimable:%lu slab_unreclaimable:%lu\n"
" mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
" free:%lu free_pcp:%lu free_cma:%lu\n",
global_page_state(NR_ACTIVE_ANON),
global_page_state(NR_INACTIVE_ANON),
global_page_state(NR_ISOLATED_ANON),
global_page_state(NR_ACTIVE_FILE),
global_page_state(NR_INACTIVE_FILE),
global_page_state(NR_ISOLATED_FILE),
global_page_state(NR_UNEVICTABLE),
global_page_state(NR_FILE_DIRTY),
global_page_state(NR_WRITEBACK),
global_page_state(NR_UNSTABLE_NFS),
global_page_state(NR_SLAB_RECLAIMABLE),
global_page_state(NR_SLAB_UNRECLAIMABLE),
global_page_state(NR_FILE_MAPPED),
global_page_state(NR_SHMEM),
global_page_state(NR_PAGETABLE),
global_page_state(NR_BOUNCE),
global_page_state(NR_FREE_PAGES),
free_pcp,
global_page_state(NR_FREE_CMA_PAGES));
for_each_populated_zone(zone) {
int i;
if (skip_free_areas_node(filter, zone_to_nid(zone)))
continue;
free_pcp = 0;
for_each_online_cpu(cpu)
free_pcp += per_cpu_ptr(zone->pageset, cpu)->pcp.count;
show_node(zone);
printk("%s"
" free:%lukB"
" min:%lukB"
" low:%lukB"
" high:%lukB"
" active_anon:%lukB"
" inactive_anon:%lukB"
" active_file:%lukB"
" inactive_file:%lukB"
" unevictable:%lukB"
" isolated(anon):%lukB"
" isolated(file):%lukB"
" present:%lukB"
" managed:%lukB"
" mlocked:%lukB"
" dirty:%lukB"
" writeback:%lukB"
" mapped:%lukB"
" shmem:%lukB"
" slab_reclaimable:%lukB"
" slab_unreclaimable:%lukB"
" kernel_stack:%lukB"
" pagetables:%lukB"
" unstable:%lukB"
" bounce:%lukB"
" free_pcp:%lukB"
" local_pcp:%ukB"
" free_cma:%lukB"
" writeback_tmp:%lukB"
" pages_scanned:%lu"
" all_unreclaimable? %s"
"\n",
zone->name,
K(zone_page_state(zone, NR_FREE_PAGES)),
K(min_wmark_pages(zone)),
K(low_wmark_pages(zone)),
K(high_wmark_pages(zone)),
K(zone_page_state(zone, NR_ACTIVE_ANON)),
K(zone_page_state(zone, NR_INACTIVE_ANON)),
K(zone_page_state(zone, NR_ACTIVE_FILE)),
K(zone_page_state(zone, NR_INACTIVE_FILE)),
K(zone_page_state(zone, NR_UNEVICTABLE)),
K(zone_page_state(zone, NR_ISOLATED_ANON)),
K(zone_page_state(zone, NR_ISOLATED_FILE)),
K(zone->present_pages),
K(zone->managed_pages),
K(zone_page_state(zone, NR_MLOCK)),
K(zone_page_state(zone, NR_FILE_DIRTY)),
K(zone_page_state(zone, NR_WRITEBACK)),
K(zone_page_state(zone, NR_FILE_MAPPED)),
K(zone_page_state(zone, NR_SHMEM)),
K(zone_page_state(zone, NR_SLAB_RECLAIMABLE)),
K(zone_page_state(zone, NR_SLAB_UNRECLAIMABLE)),
zone_page_state(zone, NR_KERNEL_STACK) *
THREAD_SIZE / 1024,
K(zone_page_state(zone, NR_PAGETABLE)),
K(zone_page_state(zone, NR_UNSTABLE_NFS)),
K(zone_page_state(zone, NR_BOUNCE)),
K(free_pcp),
K(this_cpu_read(zone->pageset->pcp.count)),
K(zone_page_state(zone, NR_FREE_CMA_PAGES)),
K(zone_page_state(zone, NR_WRITEBACK_TEMP)),
K(zone_page_state(zone, NR_PAGES_SCANNED)),
(!zone_reclaimable(zone) ? "yes" : "no")
);
printk("lowmem_reserve[]:");
for (i = 0; i < MAX_NR_ZONES; i++)
printk(" %ld", zone->lowmem_reserve[i]);
printk("\n");
}
for_each_populated_zone(zone) {
unsigned long nr[MAX_ORDER], flags, order, total = 0;
unsigned char types[MAX_ORDER];
if (skip_free_areas_node(filter, zone_to_nid(zone)))
continue;
show_node(zone);
printk("%s: ", zone->name);
spin_lock_irqsave(&zone->lock, flags);
for (order = 0; order < MAX_ORDER; order++) {
struct free_area *area = &zone->free_area[order];
int type;
nr[order] = area->nr_free;
total += nr[order] << order;
types[order] = 0;
for (type = 0; type < MIGRATE_TYPES; type++) {
if (!list_empty(&area->free_list[type]))
types[order] |= 1 << type;
}
}
spin_unlock_irqrestore(&zone->lock, flags);
for (order = 0; order < MAX_ORDER; order++) {
printk("%lu*%lukB ", nr[order], K(1UL) << order);
if (nr[order])
show_migration_types(types[order]);
}
printk("= %lukB\n", K(total));
}
hugetlb_show_meminfo();
printk("%ld total pagecache pages\n", global_page_state(NR_FILE_PAGES));
show_swap_cache_info();
}
static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
{
zoneref->zone = zone;
zoneref->zone_idx = zone_idx(zone);
}
/*
* Builds allocation fallback zone lists.
*
* Add all populated zones of a node to the zonelist.
*/
static int build_zonelists_node(pg_data_t *pgdat, struct zonelist *zonelist,
int nr_zones)
{
struct zone *zone;
enum zone_type zone_type = MAX_NR_ZONES;
do {
zone_type--;
zone = pgdat->node_zones + zone_type;
if (populated_zone(zone)) {
zoneref_set_zone(zone,
&zonelist->_zonerefs[nr_zones++]);
check_highest_zone(zone_type);
}
} while (zone_type);
return nr_zones;
}
/*
* zonelist_order:
* 0 = automatic detection of better ordering.
* 1 = order by ([node] distance, -zonetype)
* 2 = order by (-zonetype, [node] distance)
*
* If not NUMA, ZONELIST_ORDER_ZONE and ZONELIST_ORDER_NODE will create
* the same zonelist. So only NUMA can configure this param.
*/
#define ZONELIST_ORDER_DEFAULT 0
#define ZONELIST_ORDER_NODE 1
#define ZONELIST_ORDER_ZONE 2
/* zonelist order in the kernel.
* set_zonelist_order() will set this to NODE or ZONE.
*/
static int current_zonelist_order = ZONELIST_ORDER_DEFAULT;
static char zonelist_order_name[3][8] = {"Default", "Node", "Zone"};
#ifdef CONFIG_NUMA
/* The value user specified ....changed by config */
static int user_zonelist_order = ZONELIST_ORDER_DEFAULT;
/* string for sysctl */
#define NUMA_ZONELIST_ORDER_LEN 16
char numa_zonelist_order[16] = "default";
/*
* interface for configure zonelist ordering.
* command line option "numa_zonelist_order"
* = "[dD]efault - default, automatic configuration.
* = "[nN]ode - order by node locality, then by zone within node
* = "[zZ]one - order by zone, then by locality within zone
*/
static int __parse_numa_zonelist_order(char *s)
{
if (*s == 'd' || *s == 'D') {
user_zonelist_order = ZONELIST_ORDER_DEFAULT;
} else if (*s == 'n' || *s == 'N') {
user_zonelist_order = ZONELIST_ORDER_NODE;
} else if (*s == 'z' || *s == 'Z') {
user_zonelist_order = ZONELIST_ORDER_ZONE;
} else {
printk(KERN_WARNING
"Ignoring invalid numa_zonelist_order value: "
"%s\n", s);
return -EINVAL;
}
return 0;
}
static __init int setup_numa_zonelist_order(char *s)
{
int ret;
if (!s)
return 0;
ret = __parse_numa_zonelist_order(s);
if (ret == 0)
strlcpy(numa_zonelist_order, s, NUMA_ZONELIST_ORDER_LEN);
return ret;
}
early_param("numa_zonelist_order", setup_numa_zonelist_order);
/*
* sysctl handler for numa_zonelist_order
*/
int numa_zonelist_order_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length,
loff_t *ppos)
{
char saved_string[NUMA_ZONELIST_ORDER_LEN];
int ret;
static DEFINE_MUTEX(zl_order_mutex);
mutex_lock(&zl_order_mutex);
if (write) {
if (strlen((char *)table->data) >= NUMA_ZONELIST_ORDER_LEN) {
ret = -EINVAL;
goto out;
}
strcpy(saved_string, (char *)table->data);
}
ret = proc_dostring(table, write, buffer, length, ppos);
if (ret)
goto out;
if (write) {
int oldval = user_zonelist_order;
ret = __parse_numa_zonelist_order((char *)table->data);
if (ret) {
/*
* bogus value. restore saved string
*/
strncpy((char *)table->data, saved_string,
NUMA_ZONELIST_ORDER_LEN);
user_zonelist_order = oldval;
} else if (oldval != user_zonelist_order) {
mutex_lock(&zonelists_mutex);
build_all_zonelists(NULL, NULL);
mutex_unlock(&zonelists_mutex);
}
}
out:
mutex_unlock(&zl_order_mutex);
return ret;
}
#define MAX_NODE_LOAD (nr_online_nodes)
static int 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 find_next_best_node(int node, nodemask_t *used_node_mask)
{
int n, val;
int min_val = INT_MAX;
int best_node = NUMA_NO_NODE;
const struct cpumask *tmp = cpumask_of_node(0);
/* 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_node_state(n, N_MEMORY) {
/* 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 = cpumask_of_node(n);
if (!cpumask_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;
}
/*
* Build zonelists ordered by node and zones within node.
* This results in maximum locality--normal zone overflows into local
* DMA zone, if any--but risks exhausting DMA zone.
*/
static void build_zonelists_in_node_order(pg_data_t *pgdat, int node)
{
int j;
struct zonelist *zonelist;
zonelist = &pgdat->node_zonelists[0];
for (j = 0; zonelist->_zonerefs[j].zone != NULL; j++)
;
j = build_zonelists_node(NODE_DATA(node), zonelist, j);
zonelist->_zonerefs[j].zone = NULL;
zonelist->_zonerefs[j].zone_idx = 0;
}
/*
* Build gfp_thisnode zonelists
*/
static void build_thisnode_zonelists(pg_data_t *pgdat)
{
int j;
struct zonelist *zonelist;
zonelist = &pgdat->node_zonelists[1];
j = build_zonelists_node(pgdat, zonelist, 0);
zonelist->_zonerefs[j].zone = NULL;
zonelist->_zonerefs[j].zone_idx = 0;
}
/*
* Build zonelists ordered by zone and nodes within zones.
* This results in conserving DMA zone[s] until all Normal memory is
* exhausted, but results in overflowing to remote node while memory
* may still exist in local DMA zone.
*/
static int node_order[MAX_NUMNODES];
static void build_zonelists_in_zone_order(pg_data_t *pgdat, int nr_nodes)
{
int pos, j, node;
int zone_type; /* needs to be signed */
struct zone *z;
struct zonelist *zonelist;
zonelist = &pgdat->node_zonelists[0];
pos = 0;
for (zone_type = MAX_NR_ZONES - 1; zone_type >= 0; zone_type--) {
for (j = 0; j < nr_nodes; j++) {
node = node_order[j];
z = &NODE_DATA(node)->node_zones[zone_type];
if (populated_zone(z)) {
zoneref_set_zone(z,
&zonelist->_zonerefs[pos++]);
check_highest_zone(zone_type);
}
}
}
zonelist->_zonerefs[pos].zone = NULL;
zonelist->_zonerefs[pos].zone_idx = 0;
}
#if defined(CONFIG_64BIT)
/*
* Devices that require DMA32/DMA are relatively rare and do not justify a
* penalty to every machine in case the specialised case applies. Default
* to Node-ordering on 64-bit NUMA machines
*/
static int default_zonelist_order(void)
{
return ZONELIST_ORDER_NODE;
}
#else
/*
* On 32-bit, the Normal zone needs to be preserved for allocations accessible
* by the kernel. If processes running on node 0 deplete the low memory zone
* then reclaim will occur more frequency increasing stalls and potentially
* be easier to OOM if a large percentage of the zone is under writeback or
* dirty. The problem is significantly worse if CONFIG_HIGHPTE is not set.
* Hence, default to zone ordering on 32-bit.
*/
static int default_zonelist_order(void)
{
return ZONELIST_ORDER_ZONE;
}
#endif /* CONFIG_64BIT */
static void set_zonelist_order(void)
{
if (user_zonelist_order == ZONELIST_ORDER_DEFAULT)
current_zonelist_order = default_zonelist_order();
else
current_zonelist_order = user_zonelist_order;
}
static void build_zonelists(pg_data_t *pgdat)
{
int j, node, load;
enum zone_type i;
nodemask_t used_mask;
int local_node, prev_node;
struct zonelist *zonelist;
int order = current_zonelist_order;
/* initialize zonelists */
for (i = 0; i < MAX_ZONELISTS; i++) {
zonelist = pgdat->node_zonelists + i;
zonelist->_zonerefs[0].zone = NULL;
zonelist->_zonerefs[0].zone_idx = 0;
}
/* NUMA-aware ordering of nodes */
local_node = pgdat->node_id;
load = nr_online_nodes;
prev_node = local_node;
nodes_clear(used_mask);
memset(node_order, 0, sizeof(node_order));
j = 0;
while ((node = find_next_best_node(local_node, &used_mask)) >= 0) {
/*
* 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 (node_distance(local_node, node) !=
node_distance(local_node, prev_node))
node_load[node] = load;
prev_node = node;
load--;
if (order == ZONELIST_ORDER_NODE)
build_zonelists_in_node_order(pgdat, node);
else
node_order[j++] = node; /* remember order */
}
if (order == ZONELIST_ORDER_ZONE) {
/* calculate node order -- i.e., DMA last! */
build_zonelists_in_zone_order(pgdat, j);
}
build_thisnode_zonelists(pgdat);
}
#ifdef CONFIG_HAVE_MEMORYLESS_NODES
/*
* Return node id of node used for "local" allocations.
* I.e., first node id of first zone in arg node's generic zonelist.
* Used for initializing percpu 'numa_mem', which is used primarily
* for kernel allocations, so use GFP_KERNEL flags to locate zonelist.
*/
int local_memory_node(int node)
{
struct zone *zone;
(void)first_zones_zonelist(node_zonelist(node, GFP_KERNEL),
gfp_zone(GFP_KERNEL),
NULL,
&zone);
return zone->node;
}
#endif
#else /* CONFIG_NUMA */
static void set_zonelist_order(void)
{
current_zonelist_order = ZONELIST_ORDER_ZONE;
}
static void build_zonelists(pg_data_t *pgdat)
{
int node, local_node;
enum zone_type j;
struct zonelist *zonelist;
local_node = pgdat->node_id;
zonelist = &pgdat->node_zonelists[0];
j = build_zonelists_node(pgdat, zonelist, 0);
/*
* 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);
}
for (node = 0; node < local_node; node++) {
if (!node_online(node))
continue;
j = build_zonelists_node(NODE_DATA(node), zonelist, j);
}
zonelist->_zonerefs[j].zone = NULL;
zonelist->_zonerefs[j].zone_idx = 0;
}
#endif /* 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.
*
* 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 void setup_pageset(struct per_cpu_pageset *p, unsigned long batch);
static DEFINE_PER_CPU(struct per_cpu_pageset, boot_pageset);
static void setup_zone_pageset(struct zone *zone);
/*
* Global mutex to protect against size modification of zonelists
* as well as to serialize pageset setup for the new populated zone.
*/
DEFINE_MUTEX(zonelists_mutex);
/* return values int ....just for stop_machine() */
static int __build_all_zonelists(void *data)
{
int nid;
int cpu;
pg_data_t *self = data;
#ifdef CONFIG_NUMA
memset(node_load, 0, sizeof(node_load));
#endif
if (self && !node_online(self->node_id)) {
build_zonelists(self);
}
for_each_online_node(nid) {
pg_data_t *pgdat = NODE_DATA(nid);
build_zonelists(pgdat);
}
/*
* Initialize the boot_pagesets that are going to be used
* for bootstrapping processors. The real pagesets for
* each zone will be allocated later when the per cpu
* allocator is available.
*
* boot_pagesets are used also for bootstrapping offline
* cpus if the system is already booted because the pagesets
* are needed to initialize allocators on a specific cpu too.
* F.e. the percpu allocator needs the page allocator which
* needs the percpu allocator in order to allocate its pagesets
* (a chicken-egg dilemma).
*/
for_each_possible_cpu(cpu) {
setup_pageset(&per_cpu(boot_pageset, cpu), 0);
#ifdef CONFIG_HAVE_MEMORYLESS_NODES
/*
* We now know the "local memory node" for each node--
* i.e., the node of the first zone in the generic zonelist.
* Set up numa_mem percpu variable for on-line cpus. During
* boot, only the boot cpu should be on-line; we'll init the
* secondary cpus' numa_mem as they come on-line. During
* node/memory hotplug, we'll fixup all on-line cpus.
*/
if (cpu_online(cpu))
set_cpu_numa_mem(cpu, local_memory_node(cpu_to_node(cpu)));
#endif
}
return 0;
}
static noinline void __init
build_all_zonelists_init(void)
{
__build_all_zonelists(NULL);
mminit_verify_zonelist();
cpuset_init_current_mems_allowed();
}
/*
* Called with zonelists_mutex held always
* unless system_state == SYSTEM_BOOTING.
*
* __ref due to (1) call of __meminit annotated setup_zone_pageset
* [we're only called with non-NULL zone through __meminit paths] and
* (2) call of __init annotated helper build_all_zonelists_init
* [protected by SYSTEM_BOOTING].
*/
void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
{
set_zonelist_order();
if (system_state == SYSTEM_BOOTING) {
build_all_zonelists_init();
} else {
#ifdef CONFIG_MEMORY_HOTPLUG
if (zone)
setup_zone_pageset(zone);
#endif
/* we have to stop all cpus to guarantee there is no user
of zonelist */
stop_machine(__build_all_zonelists, pgdat, NULL);
/* cpuset refresh routine should be here */
}
vm_total_pages = nr_free_pagecache_pages();
/*
* Disable grouping by mobility if the number of pages in the
* system is too low to allow the mechanism to work. It would be
* more accurate, but expensive to check per-zone. This check is
* made on memory-hotadd so a system can start with mobility
* disabled and enable it later
*/
if (vm_total_pages < (pageblock_nr_pages * MIGRATE_TYPES))
page_group_by_mobility_disabled = 1;
else
page_group_by_mobility_disabled = 0;
pr_info("Built %i zonelists in %s order, mobility grouping %s. "
"Total pages: %ld\n",
nr_online_nodes,
zonelist_order_name[current_zonelist_order],
page_group_by_mobility_disabled ? "off" : "on",
vm_total_pages);
#ifdef CONFIG_NUMA
pr_info("Policy zone: %s\n", zone_names[policy_zone]);
#endif
}
/*
* 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);
}
/*
* 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)
{
pg_data_t *pgdat = NODE_DATA(nid);
unsigned long end_pfn = start_pfn + size;
unsigned long pfn;
struct zone *z;
unsigned long nr_initialised = 0;
if (highest_memmap_pfn < end_pfn - 1)
highest_memmap_pfn = end_pfn - 1;
z = &pgdat->node_zones[zone];
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;
if (!update_defer_init(pgdat, pfn, end_pfn,
&nr_initialised))
break;
}
/*
* Mark the block movable so that blocks are reserved for
* movable at startup. This will force kernel allocations
* to reserve their blocks rather than leaking throughout
* the address space during boot when many long-lived
* kernel allocations are made.
*
* bitmap is created for zone's valid pfn range. but memmap
* can be created for invalid pages (for alignment)
* check here not to call set_pageblock_migratetype() against
* pfn out of zone.
*/
if (!(pfn & (pageblock_nr_pages - 1))) {
struct page *page = pfn_to_page(pfn);
__init_single_page(page, pfn, zone, nid);
set_pageblock_migratetype(page, MIGRATE_MOVABLE);
} else {
__init_single_pfn(pfn, zone, nid);
}
}
}
static void __meminit zone_init_free_lists(struct zone *zone)
{
unsigned int order, t;
for_each_migratetype_order(order, t) {
INIT_LIST_HEAD(&zone->free_area[order].free_list[t]);
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 zone_batchsize(struct zone *zone)
{
#ifdef CONFIG_MMU
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->managed_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 = rounddown_pow_of_two(batch + batch/2) - 1;
return batch;
#else
/* The deferral and batching of frees should be suppressed under NOMMU
* conditions.
*
* The problem is that NOMMU needs to be able to allocate large chunks
* of contiguous memory as there's no hardware page translation to
* assemble apparent contiguous memory from discontiguous pages.
*
* Queueing large contiguous runs of pages for batching, however,
* causes the pages to actually be freed in smaller chunks. As there
* can be a significant delay between the individual batches being
* recycled, this leads to the once large chunks of space being
* fragmented and becoming unavailable for high-order allocations.
*/
return 0;
#endif
}
/*
* pcp->high and pcp->batch values are related and dependent on one another:
* ->batch must never be higher then ->high.
* The following function updates them in a safe manner without read side
* locking.
*
* Any new users of pcp->batch and pcp->high should ensure they can cope with
* those fields changing asynchronously (acording the the above rule).
*
* mutex_is_locked(&pcp_batch_high_lock) required when calling this function
* outside of boot time (or some other assurance that no concurrent updaters
* exist).
*/
static void pageset_update(struct per_cpu_pages *pcp, unsigned long high,
unsigned long batch)
{
/* start with a fail safe value for batch */
pcp->batch = 1;
smp_wmb();
/* Update high, then batch, in order */
pcp->high = high;
smp_wmb();
pcp->batch = batch;
}
/* a companion to pageset_set_high() */
static void pageset_set_batch(struct per_cpu_pageset *p, unsigned long batch)
{
pageset_update(&p->pcp, 6 * batch, max(1UL, 1 * batch));
}
static void pageset_init(struct per_cpu_pageset *p)
{
struct per_cpu_pages *pcp;
int migratetype;
memset(p, 0, sizeof(*p));
pcp = &p->pcp;
pcp->count = 0;
for (migratetype = 0; migratetype < MIGRATE_PCPTYPES; migratetype++)
INIT_LIST_HEAD(&pcp->lists[migratetype]);
}
static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
{
pageset_init(p);
pageset_set_batch(p, batch);
}
/*
* pageset_set_high() sets the high water mark for hot per_cpu_pagelist
* to the value high for the pageset p.
*/
static void pageset_set_high(struct per_cpu_pageset *p,
unsigned long high)
{
unsigned long batch = max(1UL, high / 4);
if ((high / 4) > (PAGE_SHIFT * 8))
batch = PAGE_SHIFT * 8;
pageset_update(&p->pcp, high, batch);
}
static void pageset_set_high_and_batch(struct zone *zone,
struct per_cpu_pageset *pcp)
{
if (percpu_pagelist_fraction)
pageset_set_high(pcp,
(zone->managed_pages /
percpu_pagelist_fraction));
else
pageset_set_batch(pcp, zone_batchsize(zone));
}
static void __meminit zone_pageset_init(struct zone *zone, int cpu)
{
struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
pageset_init(pcp);
pageset_set_high_and_batch(zone, pcp);
}
static void __meminit setup_zone_pageset(struct zone *zone)
{
int cpu;
zone->pageset = alloc_percpu(struct per_cpu_pageset);
for_each_possible_cpu(cpu)
zone_pageset_init(zone, cpu);
}
/*
* Allocate per cpu pagesets and initialize them.
* Before this call only boot pagesets were available.
*/
void __init setup_per_cpu_pageset(void)
{
struct zone *zone;
for_each_populated_zone(zone)
setup_zone_pageset(zone);
}
static noinline __init_refok
int zone_wait_table_init(struct zone *zone, unsigned long zone_size_pages)
{
int i;
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 (!slab_is_available()) {
zone->wait_table = (wait_queue_head_t *)
memblock_virt_alloc_node_nopanic(
alloc_size, zone->zone_pgdat->node_id);
} 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 = 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)
{
/*
* per cpu subsystem is not up at this point. The following code
* relies on the ability of the linker to provide the
* offset of a (static) per cpu variable into the per cpu area.
*/
zone->pageset = &boot_pageset;
if (populated_zone(zone))
printk(KERN_DEBUG " %s zone: %lu pages, LIFO batch:%u\n",
zone->name, zone->present_pages,
zone_batchsize(zone));
}
int __meminit 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;
mminit_dprintk(MMINIT_TRACE, "memmap_init",
"Initialising map node %d zone %lu pfns %lu -> %lu\n",
pgdat->node_id,
(unsigned long)zone_idx(zone),
zone_start_pfn, (zone_start_pfn + size));
zone_init_free_lists(zone);
return 0;
}
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
#ifndef CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID
/*
* Required by SPARSEMEM. Given a PFN, return what node the PFN is on.
*/
int __meminit __early_pfn_to_nid(unsigned long pfn,
struct mminit_pfnnid_cache *state)
{
unsigned long start_pfn, end_pfn;
int nid;
if (state->last_start <= pfn && pfn < state->last_end)
return state->last_nid;
nid = memblock_search_pfn_nid(pfn, &start_pfn, &end_pfn);
if (nid != -1) {
state->last_start = start_pfn;
state->last_end = end_pfn;
state->last_nid = nid;
}
return nid;
}
#endif /* CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID */
/**
* free_bootmem_with_active_regions - Call memblock_free_early_nid 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 memblock_free_early_nid
*
* If an architecture guarantees that all ranges registered contain no holes
* and may be freed, this this function may be used instead of calling
* memblock_free_early_nid() manually.
*/
void __init free_bootmem_with_active_regions(int nid, unsigned long max_low_pfn)
{
unsigned long start_pfn, end_pfn;
int i, this_nid;
for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid) {
start_pfn = min(start_pfn, max_low_pfn);
end_pfn = min(end_pfn, max_low_pfn);
if (start_pfn < end_pfn)
memblock_free_early_nid(PFN_PHYS(start_pfn),
(end_pfn - start_pfn) << PAGE_SHIFT,
this_nid);
}
}
/**
* 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 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)
{
unsigned long start_pfn, end_pfn;
int i, this_nid;
for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, &this_nid)
memory_present(this_nid, start_pfn, end_pfn);
}
/**
* 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 memblock_set_node(). If called for a node
* with no available memory, a warning is printed and the start and end
* PFNs will be 0.
*/
void __meminit get_pfn_range_for_nid(unsigned int nid,
unsigned long *start_pfn, unsigned long *end_pfn)
{
unsigned long this_start_pfn, this_end_pfn;
int i;
*start_pfn = -1UL;
*end_pfn = 0;
for_each_mem_pfn_range(i, nid, &this_start_pfn, &this_end_pfn, NULL) {
*start_pfn = min(*start_pfn, this_start_pfn);
*end_pfn = max(*end_pfn, this_end_pfn);
}
if (*start_pfn == -1UL)
*start_pfn = 0;
}
/*
* This finds a zone that can be used for ZONE_MOVABLE pages. The
* assumption is made that zones within a node are ordered in monotonic
* increasing memory addresses so that the "highest" populated zone is used
*/
static void __init find_usable_zone_for_movable(void)
{
int zone_index;
for (zone_index = MAX_NR_ZONES - 1; zone_index >= 0; zone_index--) {
if (zone_index == ZONE_MOVABLE)
continue;
if (arch_zone_highest_possible_pfn[zone_index] >
arch_zone_lowest_possible_pfn[zone_index])
break;
}
VM_BUG_ON(zone_index == -1);
movable_zone = zone_index;
}
/*
* The zone ranges provided by the architecture do not include ZONE_MOVABLE
* because it is sized independent of architecture. Unlike the other zones,
* the starting point for ZONE_MOVABLE is not fixed. It may be different
* in each node depending on the size of each node and how evenly kernelcore
* is distributed. This helper function adjusts the zone ranges
* provided by the architecture for a given node by using the end of the
* highest usable zone for ZONE_MOVABLE. This preserves the assumption that
* zones within a node are in order of monotonic increases memory addresses
*/
static void __meminit adjust_zone_range_for_zone_movable(int nid,
unsigned long zone_type,
unsigned long node_start_pfn,
unsigned long node_end_pfn,
unsigned long *zone_start_pfn,
unsigned long *zone_end_pfn)
{
/* Only adjust if ZONE_MOVABLE is on this node */
if (zone_movable_pfn[nid]) {
/* Size ZONE_MOVABLE */
if (zone_type == ZONE_MOVABLE) {
*zone_start_pfn = zone_movable_pfn[nid];
*zone_end_pfn = min(node_end_pfn,
arch_zone_highest_possible_pfn[movable_zone]);
/* Adjust for ZONE_MOVABLE starting within this range */
} else if (*zone_start_pfn < zone_movable_pfn[nid] &&
*zone_end_pfn > zone_movable_pfn[nid]) {
*zone_end_pfn = zone_movable_pfn[nid];
/* Check if this whole range is within ZONE_MOVABLE */
} else if (*zone_start_pfn >= zone_movable_pfn[nid])
*zone_start_pfn = *zone_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()
*/
static unsigned long __meminit zone_spanned_pages_in_node(int nid,
unsigned long zone_type,
unsigned long node_start_pfn,
unsigned long node_end_pfn,
unsigned long *ignored)
{
unsigned long zone_start_pfn, zone_end_pfn;
/* When hotadd a new node from cpu_up(), the node should be empty */
if (!node_start_pfn && !node_end_pfn)
return 0;
/* Get the start and end of the zone */
zone_start_pfn = arch_zone_lowest_possible_pfn[zone_type];
zone_end_pfn = arch_zone_highest_possible_pfn[zone_type];
adjust_zone_range_for_zone_movable(nid, zone_type,
node_start_pfn, node_end_pfn,
&zone_start_pfn, &zone_end_pfn);
/* 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 __meminit __absent_pages_in_range(int nid,
unsigned long range_start_pfn,
unsigned long range_end_pfn)
{
unsigned long nr_absent = range_end_pfn - range_start_pfn;
unsigned long start_pfn, end_pfn;
int i;
for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
start_pfn = clamp(start_pfn, range_start_pfn, range_end_pfn);
end_pfn = clamp(end_pfn, range_start_pfn, range_end_pfn);
nr_absent -= end_pfn - start_pfn;
}
return nr_absent;
}
/**
* 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 */
static unsigned long __meminit zone_absent_pages_in_node(int nid,
unsigned long zone_type,
unsigned long node_start_pfn,
unsigned long node_end_pfn,
unsigned long *ignored)
{
unsigned long zone_low = arch_zone_lowest_possible_pfn[zone_type];
unsigned long zone_high = arch_zone_highest_possible_pfn[zone_type];
unsigned long zone_start_pfn, zone_end_pfn;
/* When hotadd a new node from cpu_up(), the node should be empty */
if (!node_start_pfn && !node_end_pfn)
return 0;
zone_start_pfn = clamp(node_start_pfn, zone_low, zone_high);
zone_end_pfn = clamp(node_end_pfn, zone_low, zone_high);
adjust_zone_range_for_zone_movable(nid, zone_type,
node_start_pfn, node_end_pfn,
&zone_start_pfn, &zone_end_pfn);
return __absent_pages_in_range(nid, zone_start_pfn, zone_end_pfn);
}
#else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
static inline unsigned long __meminit zone_spanned_pages_in_node(int nid,
unsigned long zone_type,
unsigned long node_start_pfn,
unsigned long node_end_pfn,
unsigned long *zones_size)
{
return zones_size[zone_type];
}
static inline unsigned long __meminit zone_absent_pages_in_node(int nid,
unsigned long zone_type,
unsigned long node_start_pfn,
unsigned long node_end_pfn,
unsigned long *zholes_size)
{
if (!zholes_size)
return 0;
return zholes_size[zone_type];
}
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
static void __meminit calculate_node_totalpages(struct pglist_data *pgdat,
unsigned long node_start_pfn,
unsigned long node_end_pfn,
unsigned long *zones_size,
unsigned long *zholes_size)
{
unsigned long realtotalpages = 0, totalpages = 0;
enum zone_type i;
for (i = 0; i < MAX_NR_ZONES; i++) {
struct zone *zone = pgdat->node_zones + i;
unsigned long size, real_size;
size = zone_spanned_pages_in_node(pgdat->node_id, i,
node_start_pfn,
node_end_pfn,
zones_size);
real_size = size - zone_absent_pages_in_node(pgdat->node_id, i,
node_start_pfn, node_end_pfn,
zholes_size);
zone->spanned_pages = size;
zone->present_pages = real_size;
totalpages += size;
realtotalpages += real_size;
}
pgdat->node_spanned_pages = totalpages;
pgdat->node_present_pages = realtotalpages;
printk(KERN_DEBUG "On node %d totalpages: %lu\n", pgdat->node_id,
realtotalpages);
}
#ifndef CONFIG_SPARSEMEM
/*
* Calculate the size of the zone->blockflags rounded to an unsigned long
* Start by making sure zonesize is a multiple of pageblock_order by rounding
* up. Then use 1 NR_PAGEBLOCK_BITS worth of bits per pageblock, finally
* round what is now in bits to nearest long in bits, then return it in
* bytes.
*/
static unsigned long __init usemap_size(unsigned long zone_start_pfn, unsigned long zonesize)
{
unsigned long usemapsize;
zonesize += zone_start_pfn & (pageblock_nr_pages-1);
usemapsize = roundup(zonesize, pageblock_nr_pages);
usemapsize = usemapsize >> pageblock_order;
usemapsize *= NR_PAGEBLOCK_BITS;
usemapsize = roundup(usemapsize, 8 * sizeof(unsigned long));
return usemapsize / 8;
}
static void __init setup_usemap(struct pglist_data *pgdat,
struct zone *zone,
unsigned long zone_start_pfn,
unsigned long zonesize)
{
unsigned long usemapsize = usemap_size(zone_start_pfn, zonesize);
zone->pageblock_flags = NULL;
if (usemapsize)
zone->pageblock_flags =
memblock_virt_alloc_node_nopanic(usemapsize,
pgdat->node_id);
}
#else
static inline void setup_usemap(struct pglist_data *pgdat, struct zone *zone,
unsigned long zone_start_pfn, unsigned long zonesize) {}
#endif /* CONFIG_SPARSEMEM */
#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
void __paginginit set_pageblock_order(void)
{
unsigned int order;
/* Check that pageblock_nr_pages has not already been setup */
if (pageblock_order)
return;
if (HPAGE_SHIFT > PAGE_SHIFT)
order = HUGETLB_PAGE_ORDER;
else
order = MAX_ORDER - 1;
/*
* Assume the largest contiguous order of interest is a huge page.
* This value may be variable depending on boot parameters on IA64 and
* powerpc.
*/
pageblock_order = order;
}
#else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
/*
* When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order()
* is unused as pageblock_order is set at compile-time. See
* include/linux/pageblock-flags.h for the values of pageblock_order based on
* the kernel config
*/
void __paginginit set_pageblock_order(void)
{
}
#endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
static unsigned long __paginginit calc_memmap_size(unsigned long spanned_pages,
unsigned long present_pages)
{
unsigned long pages = spanned_pages;
/*
* Provide a more accurate estimation if there are holes within
* the zone and SPARSEMEM is in use. If there are holes within the
* zone, each populated memory region may cost us one or two extra
* memmap pages due to alignment because memmap pages for each
* populated regions may not naturally algined on page boundary.
* So the (present_pages >> 4) heuristic is a tradeoff for that.
*/
if (spanned_pages > present_pages + (present_pages >> 4) &&
IS_ENABLED(CONFIG_SPARSEMEM))
pages = present_pages;
return PAGE_ALIGN(pages * sizeof(struct page)) >> PAGE_SHIFT;
}
/*
* Set up the zone data structures:
* - mark all pages reserved
* - mark all memory queues empty
* - clear the memory bitmaps
*
* NOTE: pgdat should get zeroed by caller.
*/
static void __paginginit free_area_init_core(struct pglist_data *pgdat)
{
enum zone_type j;
int nid = pgdat->node_id;
unsigned long zone_start_pfn = pgdat->node_start_pfn;
int ret;
pgdat_resize_init(pgdat);
#ifdef CONFIG_NUMA_BALANCING
spin_lock_init(&pgdat->numabalancing_migrate_lock);
pgdat->numabalancing_migrate_nr_pages = 0;
pgdat->numabalancing_migrate_next_window = jiffies;
#endif
init_waitqueue_head(&pgdat->kswapd_wait);
init_waitqueue_head(&pgdat->pfmemalloc_wait);
pgdat_page_ext_init(pgdat);
for (j = 0; j < MAX_NR_ZONES; j++) {
struct zone *zone = pgdat->node_zones + j;
unsigned long size, realsize, freesize, memmap_pages;
size = zone->spanned_pages;
realsize = freesize = zone->present_pages;
/*
* Adjust freesize 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 = calc_memmap_size(size, realsize);
if (!is_highmem_idx(j)) {
if (freesize >= memmap_pages) {
freesize -= memmap_pages;
if (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 freesize %lu\n",
zone_names[j], memmap_pages, freesize);
}
/* Account for reserved pages */
if (j == 0 && freesize > dma_reserve) {
freesize -= dma_reserve;
printk(KERN_DEBUG " %s zone: %lu pages reserved\n",
zone_names[0], dma_reserve);
}
if (!is_highmem_idx(j))
nr_kernel_pages += freesize;
/* Charge for highmem memmap if there are enough kernel pages */
else if (nr_kernel_pages > memmap_pages * 2)
nr_kernel_pages -= memmap_pages;
nr_all_pages += freesize;
/*
* Set an approximate value for lowmem here, it will be adjusted
* when the bootmem allocator frees pages into the buddy system.
* And all highmem pages will be managed by the buddy system.
*/
zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
#ifdef CONFIG_NUMA
zone->node = nid;
zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio)
/ 100;
zone->min_slab_pages = (freesize * 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_pcp_init(zone);
/* For bootup, initialized properly in watermark setup */
mod_zone_page_state(zone, NR_ALLOC_BATCH, zone->managed_pages);
lruvec_init(&zone->lruvec);
if (!size)
continue;
set_pageblock_order();
setup_usemap(pgdat, zone, zone_start_pfn, size);
ret = init_currently_empty_zone(zone, zone_start_pfn, size);
BUG_ON(ret);
memmap_init(size, nid, j, zone_start_pfn);
zone_start_pfn += size;
}
}
static void __init_refok alloc_node_mem_map(struct pglist_data *pgdat)
{
unsigned long __maybe_unused offset = 0;
/* 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);
offset = pgdat->node_start_pfn - start;
end = pgdat_end_pfn(pgdat);
end = ALIGN(end, MAX_ORDER_NR_PAGES);
size = (end - start) * sizeof(struct page);
map = alloc_remap(pgdat->node_id, size);
if (!map)
map = memblock_virt_alloc_node_nopanic(size,
pgdat->node_id);
pgdat->node_mem_map = map + offset;
}
#ifndef CONFIG_NEED_MULTIPLE_NODES
/*
* 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;
#if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM)
if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
mem_map -= offset;
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
}
#endif
#endif /* CONFIG_FLAT_NODE_MEM_MAP */
}
void __paginginit free_area_init_node(int nid, unsigned long *zones_size,
unsigned long node_start_pfn, unsigned long *zholes_size)
{
pg_data_t *pgdat = NODE_DATA(nid);
unsigned long start_pfn = 0;
unsigned long end_pfn = 0;
/* pg_data_t should be reset to zero when it's allocated */
WARN_ON(pgdat->nr_zones || pgdat->classzone_idx);
reset_deferred_meminit(pgdat);
pgdat->node_id = nid;
pgdat->node_start_pfn = node_start_pfn;
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
(u64)start_pfn << PAGE_SHIFT,
end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
#endif
calculate_node_totalpages(pgdat, start_pfn, end_pfn,
zones_size, zholes_size);
alloc_node_mem_map(pgdat);
#ifdef CONFIG_FLAT_NODE_MEM_MAP
printk(KERN_DEBUG "free_area_init_node: node %d, pgdat %08lx, node_mem_map %08lx\n",
nid, (unsigned long)pgdat,
(unsigned long)pgdat->node_mem_map);
#endif
free_area_init_core(pgdat);
}
#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
#if MAX_NUMNODES > 1
/*
* Figure out the number of possible node ids.
*/
void __init setup_nr_node_ids(void)
{
unsigned int highest;
highest = find_last_bit(node_possible_map.bits, MAX_NUMNODES);
nr_node_ids = highest + 1;
}
#endif
/**
* node_map_pfn_alignment - determine the maximum internode alignment
*
* This function should be called after node map is populated and sorted.
* It calculates the maximum power of two alignment which can distinguish
* all the nodes.
*
* For example, if all nodes are 1GiB and aligned to 1GiB, the return value
* would indicate 1GiB alignment with (1 << (30 - PAGE_SHIFT)). If the
* nodes are shifted by 256MiB, 256MiB. Note that if only the last node is
* shifted, 1GiB is enough and this function will indicate so.
*
* This is used to test whether pfn -> nid mapping of the chosen memory
* model has fine enough granularity to avoid incorrect mapping for the
* populated node map.
*
* Returns the determined alignment in pfn's. 0 if there is no alignment
* requirement (single node).
*/
unsigned long __init node_map_pfn_alignment(void)
{
unsigned long accl_mask = 0, last_end = 0;
unsigned long start, end, mask;
int last_nid = -1;
int i, nid;
for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, &nid) {
if (!start || last_nid < 0 || last_nid == nid) {
last_nid = nid;
last_end = end;
continue;
}
/*
* Start with a mask granular enough to pin-point to the
* start pfn and tick off bits one-by-one until it becomes
* too coarse to separate the current node from the last.
*/
mask = ~((1 << __ffs(start)) - 1);
while (mask && last_end <= (start & (mask << 1)))
mask <<= 1;
/* accumulate all internode masks */
accl_mask |= mask;
}
/* convert mask to number of pages */
return ~accl_mask + 1;
}
/* Find the lowest pfn for a node */
static unsigned long __init find_min_pfn_for_node(int nid)
{
unsigned long min_pfn = ULONG_MAX;
unsigned long start_pfn;
int i;
for_each_mem_pfn_range(i, nid, &start_pfn, NULL, NULL)
min_pfn = min(min_pfn, start_pfn);
if (min_pfn == ULONG_MAX) {
printk(KERN_WARNING
"Could not find start_pfn for node %d\n", nid);
return 0;
}
return min_pfn;
}
/**
* find_min_pfn_with_active_regions - Find the minimum PFN registered
*
* It returns the minimum PFN based on information provided via
* memblock_set_node().
*/
unsigned long __init find_min_pfn_with_active_regions(void)
{
return find_min_pfn_for_node(MAX_NUMNODES);
}
/*
* early_calculate_totalpages()
* Sum pages in active regions for movable zone.
* Populate N_MEMORY for calculating usable_nodes.
*/
static unsigned long __init early_calculate_totalpages(void)
{
unsigned long totalpages = 0;
unsigned long start_pfn, end_pfn;
int i, nid;
for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
unsigned long pages = end_pfn - start_pfn;
totalpages += pages;
if (pages)
node_set_state(nid, N_MEMORY);
}
return totalpages;
}
/*
* Find the PFN the Movable zone begins in each node. Kernel memory
* is spread evenly between nodes as long as the nodes have enough
* memory. When they don't, some nodes will have more kernelcore than
* others
*/
static void __init find_zone_movable_pfns_for_nodes(void)
{
int i, nid;
unsigned long usable_startpfn;
unsigned long kernelcore_node, kernelcore_remaining;
/* save the state before borrow the nodemask */
nodemask_t saved_node_state = node_states[N_MEMORY];
unsigned long totalpages = early_calculate_totalpages();
int usable_nodes = nodes_weight(node_states[N_MEMORY]);
struct memblock_region *r;
/* Need to find movable_zone earlier when movable_node is specified. */
find_usable_zone_for_movable();
/*
* If movable_node is specified, ignore kernelcore and movablecore
* options.
*/
if (movable_node_is_enabled()) {
for_each_memblock(memory, r) {
if (!memblock_is_hotpluggable(r))
continue;
nid = r->nid;
usable_startpfn = PFN_DOWN(r->base);
zone_movable_pfn[nid] = zone_movable_pfn[nid] ?
min(usable_startpfn, zone_movable_pfn[nid]) :
usable_startpfn;
}
goto out2;
}
/*
* If movablecore=nn[KMG] was specified, calculate what size of
* kernelcore that corresponds so that memory usable for
* any allocation type is evenly spread. If both kernelcore
* and movablecore are specified, then the value of kernelcore
* will be used for required_kernelcore if it's greater than
* what movablecore would have allowed.
*/
if (required_movablecore) {
unsigned long corepages;
/*
* Round-up so that ZONE_MOVABLE is at least as large as what
* was requested by the user
*/
required_movablecore =
roundup(required_movablecore, MAX_ORDER_NR_PAGES);
required_movablecore = min(totalpages, required_movablecore);
corepages = totalpages - required_movablecore;
required_kernelcore = max(required_kernelcore, corepages);
}
/*
* If kernelcore was not specified or kernelcore size is larger
* than totalpages, there is no ZONE_MOVABLE.
*/
if (!required_kernelcore || required_kernelcore >= totalpages)
goto out;
/* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
usable_startpfn = arch_zone_lowest_possible_pfn[movable_zone];
restart:
/* Spread kernelcore memory as evenly as possible throughout nodes */
kernelcore_node = required_kernelcore / usable_nodes;
for_each_node_state(nid, N_MEMORY) {
unsigned long start_pfn, end_pfn;
/*
* Recalculate kernelcore_node if the division per node
* now exceeds what is necessary to satisfy the requested
* amount of memory for the kernel
*/
if (required_kernelcore < kernelcore_node)
kernelcore_node = required_kernelcore / usable_nodes;
/*
* As the map is walked, we track how much memory is usable
* by the kernel using kernelcore_remaining. When it is
* 0, the rest of the node is usable by ZONE_MOVABLE
*/
kernelcore_remaining = kernelcore_node;
/* Go through each range of PFNs within this node */
for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
unsigned long size_pages;
start_pfn = max(start_pfn, zone_movable_pfn[nid]);
if (start_pfn >= end_pfn)
continue;
/* Account for what is only usable for kernelcore */
if (start_pfn < usable_startpfn) {
unsigned long kernel_pages;
kernel_pages = min(end_pfn, usable_startpfn)
- start_pfn;
kernelcore_remaining -= min(kernel_pages,
kernelcore_remaining);
required_kernelcore -= min(kernel_pages,
required_kernelcore);
/* Continue if range is now fully accounted */
if (end_pfn <= usable_startpfn) {
/*
* Push zone_movable_pfn to the end so
* that if we have to rebalance
* kernelcore across nodes, we will
* not double account here
*/
zone_movable_pfn[nid] = end_pfn;
continue;
}
start_pfn = usable_startpfn;
}
/*
* The usable PFN range for ZONE_MOVABLE is from
* start_pfn->end_pfn. Calculate size_pages as the
* number of pages used as kernelcore
*/
size_pages = end_pfn - start_pfn;
if (size_pages > kernelcore_remaining)
size_pages = kernelcore_remaining;
zone_movable_pfn[nid] = start_pfn + size_pages;
/*
* Some kernelcore has been met, update counts and
* break if the kernelcore for this node has been
* satisfied
*/
required_kernelcore -= min(required_kernelcore,
size_pages);
kernelcore_remaining -= size_pages;
if (!kernelcore_remaining)
break;
}
}
/*
* If there is still required_kernelcore, we do another pass with one
* less node in the count. This will push zone_movable_pfn[nid] further
* along on the nodes that still have memory until kernelcore is
* satisfied
*/
usable_nodes--;
if (usable_nodes && required_kernelcore > usable_nodes)
goto restart;
out2:
/* Align start of ZONE_MOVABLE on all nids to MAX_ORDER_NR_PAGES */
for (nid = 0; nid < MAX_NUMNODES; nid++)
zone_movable_pfn[nid] =
roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
out:
/* restore the node_state */
node_states[N_MEMORY] = saved_node_state;
}
/* Any regular or high memory on that node ? */
static void check_for_memory(pg_data_t *pgdat, int nid)
{
enum zone_type zone_type;
if (N_MEMORY == N_NORMAL_MEMORY)
return;
for (zone_type = 0; zone_type <= ZONE_MOVABLE - 1; zone_type++) {
struct zone *zone = &pgdat->node_zones[zone_type];
if (populated_zone(zone)) {
node_set_state(nid, N_HIGH_MEMORY);
if (N_NORMAL_MEMORY != N_HIGH_MEMORY &&
zone_type <= ZONE_NORMAL)
node_set_state(nid, N_NORMAL_MEMORY);
break;
}
}
}
/**
* 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 memblock_set_node(), 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 start_pfn, end_pfn;
int i, nid;
/* 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++) {
if (i == ZONE_MOVABLE)
continue;
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]);
}
arch_zone_lowest_possible_pfn[ZONE_MOVABLE] = 0;
arch_zone_highest_possible_pfn[ZONE_MOVABLE] = 0;
/* Find the PFNs that ZONE_MOVABLE begins at in each node */
memset(zone_movable_pfn, 0, sizeof(zone_movable_pfn));
find_zone_movable_pfns_for_nodes();
/* Print out the zone ranges */
pr_info("Zone ranges:\n");
for (i = 0; i < MAX_NR_ZONES; i++) {
if (i == ZONE_MOVABLE)
continue;
pr_info(" %-8s ", zone_names[i]);
if (arch_zone_lowest_possible_pfn[i] ==
arch_zone_highest_possible_pfn[i])
pr_cont("empty\n");
else
pr_cont("[mem %#018Lx-%#018Lx]\n",
(u64)arch_zone_lowest_possible_pfn[i]
<< PAGE_SHIFT,
((u64)arch_zone_highest_possible_pfn[i]
<< PAGE_SHIFT) - 1);
}
/* Print out the PFNs ZONE_MOVABLE begins at in each node */
pr_info("Movable zone start for each node\n");
for (i = 0; i < MAX_NUMNODES; i++) {
if (zone_movable_pfn[i])
pr_info(" Node %d: %#018Lx\n", i,
(u64)zone_movable_pfn[i] << PAGE_SHIFT);
}
/* Print out the early node map */
pr_info("Early memory node ranges\n");
for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid)
pr_info(" node %3d: [mem %#018Lx-%#018Lx]\n", nid,
(u64)start_pfn << PAGE_SHIFT,
((u64)end_pfn << PAGE_SHIFT) - 1);
/* Initialise every node */
mminit_verify_pageflags_layout();
setup_nr_node_ids();
for_each_online_node(nid) {
pg_data_t *pgdat = NODE_DATA(nid);
free_area_init_node(nid, NULL,
find_min_pfn_for_node(nid), NULL);
/* Any memory on that node */
if (pgdat->node_present_pages)
node_set_state(nid, N_MEMORY);
check_for_memory(pgdat, nid);
}
}
static int __init cmdline_parse_core(char *p, unsigned long *core)
{
unsigned long long coremem;
if (!p)
return -EINVAL;
coremem = memparse(p, &p);
*core = coremem >> PAGE_SHIFT;
/* Paranoid check that UL is enough for the coremem value */
WARN_ON((coremem >> PAGE_SHIFT) > ULONG_MAX);
return 0;
}
/*
* kernelcore=size sets the amount of memory for use for allocations that
* cannot be reclaimed or migrated.
*/
static int __init cmdline_parse_kernelcore(char *p)
{
return cmdline_parse_core(p, &required_kernelcore);
}
/*
* movablecore=size sets the amount of memory for use for allocations that
* can be reclaimed or migrated.
*/
static int __init cmdline_parse_movablecore(char *p)
{
return cmdline_parse_core(p, &required_movablecore);
}
early_param("kernelcore", cmdline_parse_kernelcore);
early_param("movablecore", cmdline_parse_movablecore);
#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
void adjust_managed_page_count(struct page *page, long count)
{
spin_lock(&managed_page_count_lock);
page_zone(page)->managed_pages += count;
totalram_pages += count;
#ifdef CONFIG_HIGHMEM
if (PageHighMem(page))
totalhigh_pages += count;
#endif
spin_unlock(&managed_page_count_lock);
}
EXPORT_SYMBOL(adjust_managed_page_count);
unsigned long free_reserved_area(void *start, void *end, int poison, char *s)
{
void *pos;
unsigned long pages = 0;
start = (void *)PAGE_ALIGN((unsigned long)start);
end = (void *)((unsigned long)end & PAGE_MASK);
for (pos = start; pos < end; pos += PAGE_SIZE, pages++) {
if ((unsigned int)poison <= 0xFF)
memset(pos, poison, PAGE_SIZE);
free_reserved_page(virt_to_page(pos));
}
if (pages && s)
pr_info("Freeing %s memory: %ldK (%p - %p)\n",
s, pages << (PAGE_SHIFT - 10), start, end);
return pages;
}
EXPORT_SYMBOL(free_reserved_area);
#ifdef CONFIG_HIGHMEM
void free_highmem_page(struct page *page)
{
__free_reserved_page(page);
totalram_pages++;
page_zone(page)->managed_pages++;
totalhigh_pages++;
}
#endif
void __init mem_init_print_info(const char *str)
{
unsigned long physpages, codesize, datasize, rosize, bss_size;
unsigned long init_code_size, init_data_size;
physpages = get_num_physpages();
codesize = _etext - _stext;
datasize = _edata - _sdata;
rosize = __end_rodata - __start_rodata;
bss_size = __bss_stop - __bss_start;
init_data_size = __init_end - __init_begin;
init_code_size = _einittext - _sinittext;
/*
* Detect special cases and adjust section sizes accordingly:
* 1) .init.* may be embedded into .data sections
* 2) .init.text.* may be out of [__init_begin, __init_end],
* please refer to arch/tile/kernel/vmlinux.lds.S.
* 3) .rodata.* may be embedded into .text or .data sections.
*/
#define adj_init_size(start, end, size, pos, adj) \
do { \
if (start <= pos && pos < end && size > adj) \
size -= adj; \
} while (0)
adj_init_size(__init_begin, __init_end, init_data_size,
_sinittext, init_code_size);
adj_init_size(_stext, _etext, codesize, _sinittext, init_code_size);
adj_init_size(_sdata, _edata, datasize, __init_begin, init_data_size);
adj_init_size(_stext, _etext, codesize, __start_rodata, rosize);
adj_init_size(_sdata, _edata, datasize, __start_rodata, rosize);
#undef adj_init_size
pr_info("Memory: %luK/%luK available "
"(%luK kernel code, %luK rwdata, %luK rodata, "
"%luK init, %luK bss, %luK reserved, %luK cma-reserved"
#ifdef CONFIG_HIGHMEM
", %luK highmem"
#endif
"%s%s)\n",
nr_free_pages() << (PAGE_SHIFT-10), physpages << (PAGE_SHIFT-10),
codesize >> 10, datasize >> 10, rosize >> 10,
(init_data_size + init_code_size) >> 10, bss_size >> 10,
(physpages - totalram_pages - totalcma_pages) << (PAGE_SHIFT-10),
totalcma_pages << (PAGE_SHIFT-10),
#ifdef CONFIG_HIGHMEM
totalhigh_pages << (PAGE_SHIFT-10),
#endif
str ? ", " : "", str ? str : "");
}
/**
* 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 managed_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;
}
void __init free_area_init(unsigned long *zones_size)
{
free_area_init_node(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 || action == CPU_DEAD_FROZEN) {
lru_add_drain_cpu(cpu);
drain_pages(cpu);
/*
* Spill the event counters of the dead processor
* into the current processors event counters.
* This artificially elevates the count of the current
* processor.
*/
vm_events_fold_cpu(cpu);
/*
* Zero the differential counters of the dead processor
* so that the vm statistics are consistent.
*
* This is only okay since the processor is dead and cannot
* race with what we are doing.
*/
cpu_vm_stats_fold(cpu);
}
return NOTIFY_OK;
}
void __init page_alloc_init(void)
{
hotcpu_notifier(page_alloc_cpu_notify, 0);
}
/*
* calculate_totalreserve_pages - called when sysctl_lowmem_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;
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 the high watermark as reserved pages. */
max += high_wmark_pages(zone);
if (max > zone->managed_pages)
max = zone->managed_pages;
reserve_pages += max;
/*
* Lowmem reserves are not available to
* GFP_HIGHUSER page cache allocations and
* kswapd tries to balance zones to their high
* watermark. As a result, neither should be
* regarded as dirtyable memory, to prevent a
* situation where reclaim has to clean pages
* in order to balance the zones.
*/
zone->dirty_balance_reserve = max;
}
}
dirty_balance_reserve = reserve_pages;
totalreserve_pages = reserve_pages;
}
/*
* setup_per_zone_lowmem_reserve - called whenever
* sysctl_lowmem_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 managed_pages = zone->managed_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] = managed_pages /
sysctl_lowmem_reserve_ratio[idx];
managed_pages += lower_zone->managed_pages;
}
}
}
/* update totalreserve_pages */
calculate_totalreserve_pages();
}
static void __setup_per_zone_wmarks(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->managed_pages;
}
for_each_zone(zone) {
u64 tmp;
spin_lock_irqsave(&zone->lock, flags);
tmp = (u64)pages_min * zone->managed_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 WMARK_HIGH-WMARK_LOW and (WMARK_LOW-WMARK_MIN)
* deltas control asynch page reclaim, and so should
* not be capped for highmem.
*/
unsigned long min_pages;
min_pages = zone->managed_pages / 1024;
min_pages = clamp(min_pages, SWAP_CLUSTER_MAX, 128UL);
zone->watermark[WMARK_MIN] = min_pages;
} else {
/*
* If it's a lowmem zone, reserve a number of pages
* proportionate to the zone's size.
*/
zone->watermark[WMARK_MIN] = tmp;
}
zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + (tmp >> 2);
zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1);
__mod_zone_page_state(zone, NR_ALLOC_BATCH,
high_wmark_pages(zone) - low_wmark_pages(zone) -
atomic_long_read(&zone->vm_stat[NR_ALLOC_BATCH]));
spin_unlock_irqrestore(&zone->lock, flags);
}
/* update totalreserve_pages */
calculate_totalreserve_pages();
}
/**
* setup_per_zone_wmarks - called when min_free_kbytes changes
* or when memory is hot-{added|removed}
*
* Ensures that the watermark[min,low,high] values for each zone are set
* correctly with respect to min_free_kbytes.
*/
void setup_per_zone_wmarks(void)
{
mutex_lock(&zonelists_mutex);
__setup_per_zone_wmarks();
mutex_unlock(&zonelists_mutex);
}
/*
* The inactive anon list should be small enough that the VM never has to
* do too much work, but large enough that each inactive page has a chance
* to be referenced again before it is swapped out.
*
* The inactive_anon ratio is the target ratio of ACTIVE_ANON to
* INACTIVE_ANON pages on this zone's LRU, maintained by the
* pageout code. A zone->inactive_ratio of 3 means 3:1 or 25% of
* the anonymous pages are kept on the inactive list.
*
* total target max
* memory ratio inactive anon
* -------------------------------------
* 10MB 1 5MB
* 100MB 1 50MB
* 1GB 3 250MB
* 10GB 10 0.9GB
* 100GB 31 3GB
* 1TB 101 10GB
* 10TB 320 32GB
*/
static void __meminit calculate_zone_inactive_ratio(struct zone *zone)
{
unsigned int gb, ratio;
/* Zone size in gigabytes */
gb = zone->managed_pages >> (30 - PAGE_SHIFT);
if (gb)
ratio = int_sqrt(10 * gb);
else
ratio = 1;
zone->inactive_ratio = ratio;
}
static void __meminit setup_per_zone_inactive_ratio(void)
{
struct zone *zone;
for_each_zone(zone)
calculate_zone_inactive_ratio(zone);
}
/*
* 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
*/
int __meminit init_per_zone_wmark_min(void)
{
unsigned long lowmem_kbytes;
int new_min_free_kbytes;
lowmem_kbytes = nr_free_buffer_pages() * (PAGE_SIZE >> 10);
new_min_free_kbytes = int_sqrt(lowmem_kbytes * 16);
if (new_min_free_kbytes > user_min_free_kbytes) {
min_free_kbytes = new_min_free_kbytes;
if (min_free_kbytes < 128)
min_free_kbytes = 128;
if (min_free_kbytes > 65536)
min_free_kbytes = 65536;
} else {
pr_warn("min_free_kbytes is not updated to %d because user defined value %d is preferred\n",
new_min_free_kbytes, user_min_free_kbytes);
}
setup_per_zone_wmarks();
refresh_zone_stat_thresholds();
setup_per_zone_lowmem_reserve();
setup_per_zone_inactive_ratio();
return 0;
}
module_init(init_per_zone_wmark_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(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
int rc;
rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (rc)
return rc;
if (write) {
user_min_free_kbytes = min_free_kbytes;
setup_per_zone_wmarks();
}
return 0;
}
#ifdef CONFIG_NUMA
int sysctl_min_unmapped_ratio_sysctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
struct zone *zone;
int rc;
rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (rc)
return rc;
for_each_zone(zone)
zone->min_unmapped_pages = (zone->managed_pages *
sysctl_min_unmapped_ratio) / 100;
return 0;
}
int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
struct zone *zone;
int rc;
rc = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (rc)
return rc;
for_each_zone(zone)
zone->min_slab_pages = (zone->managed_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
* minimum watermarks. The lowmem reserve ratio can only make sense
* if in function of the boot time zone sizes.
*/
int lowmem_reserve_ratio_sysctl_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
proc_dointvec_minmax(table, write, 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(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos)
{
struct zone *zone;
int old_percpu_pagelist_fraction;
int ret;
mutex_lock(&pcp_batch_high_lock);
old_percpu_pagelist_fraction = percpu_pagelist_fraction;
ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
if (!write || ret < 0)
goto out;
/* Sanity checking to avoid pcp imbalance */
if (percpu_pagelist_fraction &&
percpu_pagelist_fraction < MIN_PERCPU_PAGELIST_FRACTION) {
percpu_pagelist_fraction = old_percpu_pagelist_fraction;
ret = -EINVAL;
goto out;
}
/* No change? */
if (percpu_pagelist_fraction == old_percpu_pagelist_fraction)
goto out;
for_each_populated_zone(zone) {
unsigned int cpu;
for_each_possible_cpu(cpu)
pageset_set_high_and_batch(zone,
per_cpu_ptr(zone->pageset, cpu));
}
out:
mutex_unlock(&pcp_batch_high_lock);
return ret;
}
#ifdef CONFIG_NUMA
int hashdist = HASHDIST_DEFAULT;
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 low_limit,
unsigned long high_limit)
{
unsigned long long max = high_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;
/* It isn't necessary when PAGE_SIZE >= 1MB */
if (PAGE_SHIFT < 20)
numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
/* 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(flags & HASH_SMALL)) {
/* Makes no sense without HASH_EARLY */
WARN_ON(!(flags & HASH_EARLY));
if (!(numentries >> *_hash_shift)) {
numentries = 1UL << *_hash_shift;
BUG_ON(!numentries);
}
} else 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);
}
max = min(max, 0x80000000ULL);
if (numentries < low_limit)
numentries = low_limit;
if (numentries > max)
numentries = max;
log2qty = ilog2(numentries);
do {
size = bucketsize << log2qty;
if (flags & HASH_EARLY)
table = memblock_virt_alloc_nopanic(size, 0);
else if (hashdist)
table = __vmalloc(size, GFP_ATOMIC, PAGE_KERNEL);
else {
/*
* If bucketsize is not a power-of-two, we may free
* some pages at the end of hash table which
* alloc_pages_exact() automatically does
*/
if (get_order(size) < MAX_ORDER) {
table = alloc_pages_exact(size, GFP_ATOMIC);
kmemleak_alloc(table, size, 1, GFP_ATOMIC);
}
}
} while (!table && size > PAGE_SIZE && --log2qty);
if (!table)
panic("Failed to allocate %s hash table\n", tablename);
printk(KERN_INFO "%s hash table entries: %ld (order: %d, %lu bytes)\n",
tablename,
(1UL << log2qty),
ilog2(size) - PAGE_SHIFT,
size);
if (_hash_shift)
*_hash_shift = log2qty;
if (_hash_mask)
*_hash_mask = (1 << log2qty) - 1;
return table;
}
/* Return a pointer to the bitmap storing bits affecting a block of pages */
static inline unsigned long *get_pageblock_bitmap(struct zone *zone,
unsigned long pfn)
{
#ifdef CONFIG_SPARSEMEM
return __pfn_to_section(pfn)->pageblock_flags;
#else
return zone->pageblock_flags;
#endif /* CONFIG_SPARSEMEM */
}
static inline int pfn_to_bitidx(struct zone *zone, unsigned long pfn)
{
#ifdef CONFIG_SPARSEMEM
pfn &= (PAGES_PER_SECTION-1);
return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
#else
pfn = pfn - round_down(zone->zone_start_pfn, pageblock_nr_pages);
return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
#endif /* CONFIG_SPARSEMEM */
}
/**
* get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
* @page: The page within the block of interest
* @pfn: The target page frame number
* @end_bitidx: The last bit of interest to retrieve
* @mask: mask of bits that the caller is interested in
*
* Return: pageblock_bits flags
*/
unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
unsigned long end_bitidx,
unsigned long mask)
{
struct zone *zone;
unsigned long *bitmap;
unsigned long bitidx, word_bitidx;
unsigned long word;
zone = page_zone(page);
bitmap = get_pageblock_bitmap(zone, pfn);
bitidx = pfn_to_bitidx(zone, pfn);
word_bitidx = bitidx / BITS_PER_LONG;
bitidx &= (BITS_PER_LONG-1);
word = bitmap[word_bitidx];
bitidx += end_bitidx;
return (word >> (BITS_PER_LONG - bitidx - 1)) & mask;
}
/**
* set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
* @page: The page within the block of interest
* @flags: The flags to set
* @pfn: The target page frame number
* @end_bitidx: The last bit of interest
* @mask: mask of bits that the caller is interested in
*/
void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
unsigned long pfn,
unsigned long end_bitidx,
unsigned long mask)
{
struct zone *zone;
unsigned long *bitmap;
unsigned long bitidx, word_bitidx;
unsigned long old_word, word;
BUILD_BUG_ON(NR_PAGEBLOCK_BITS != 4);
zone = page_zone(page);
bitmap = get_pageblock_bitmap(zone, pfn);
bitidx = pfn_to_bitidx(zone, pfn);
word_bitidx = bitidx / BITS_PER_LONG;
bitidx &= (BITS_PER_LONG-1);
VM_BUG_ON_PAGE(!zone_spans_pfn(zone, pfn), page);
bitidx += end_bitidx;
mask <<= (BITS_PER_LONG - bitidx - 1);
flags <<= (BITS_PER_LONG - bitidx - 1);
word = READ_ONCE(bitmap[word_bitidx]);
for (;;) {
old_word = cmpxchg(&bitmap[word_bitidx], word, (word & ~mask) | flags);
if (word == old_word)
break;
word = old_word;
}
}
/*
* This function checks whether pageblock includes unmovable pages or not.
* If @count is not zero, it is okay to include less @count unmovable pages
*
* PageLRU check without isolation or lru_lock could race so that
* MIGRATE_MOVABLE block might include unmovable pages. It means you can't
* expect this function should be exact.
*/
bool has_unmovable_pages(struct zone *zone, struct page *page, int count,
bool skip_hwpoisoned_pages)
{
unsigned long pfn, iter, found;
int mt;
/*
* For avoiding noise data, lru_add_drain_all() should be called
* If ZONE_MOVABLE, the zone never contains unmovable pages
*/
if (zone_idx(zone) == ZONE_MOVABLE)
return false;
mt = get_pageblock_migratetype(page);
if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
return false;
pfn = page_to_pfn(page);
for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {
unsigned long check = pfn + iter;
if (!pfn_valid_within(check))
continue;
page = pfn_to_page(check);
/*
* Hugepages are not in LRU lists, but they're movable.
* We need not scan over tail pages bacause we don't
* handle each tail page individually in migration.
*/
if (PageHuge(page)) {
iter = round_up(iter + 1, 1<<compound_order(page)) - 1;
continue;
}
/*
* We can't use page_count without pin a page
* because another CPU can free compound page.
* This check already skips compound tails of THP
* because their page->_count is zero at all time.
*/
if (!atomic_read(&page->_count)) {
if (PageBuddy(page))
iter += (1 << page_order(page)) - 1;
continue;
}
/*
* The HWPoisoned page may be not in buddy system, and
* page_count() is not 0.
*/
if (skip_hwpoisoned_pages && PageHWPoison(page))
continue;
if (!PageLRU(page))
found++;
/*
* If there are RECLAIMABLE pages, we need to check
* it. But now, memory offline itself doesn't call
* shrink_node_slabs() and it still to be fixed.
*/
/*
* If the page is not RAM, page_count()should be 0.
* we don't need more check. This is an _used_ not-movable page.
*
* The problematic thing here is PG_reserved pages. PG_reserved
* is set to both of a memory hole page and a _used_ kernel
* page at boot.
*/
if (found > count)
return true;
}
return false;
}
bool is_pageblock_removable_nolock(struct page *page)
{
struct zone *zone;
unsigned long pfn;
/*
* We have to be careful here because we are iterating over memory
* sections which are not zone aware so we might end up outside of
* the zone but still within the section.
* We have to take care about the node as well. If the node is offline
* its NODE_DATA will be NULL - see page_zone.
*/
if (!node_online(page_to_nid(page)))
return false;
zone = page_zone(page);
pfn = page_to_pfn(page);
if (!zone_spans_pfn(zone, pfn))
return false;
return !has_unmovable_pages(zone, page, 0, true);
}
#ifdef CONFIG_CMA
static unsigned long pfn_max_align_down(unsigned long pfn)
{
return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
pageblock_nr_pages) - 1);
}
static unsigned long pfn_max_align_up(unsigned long pfn)
{
return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
pageblock_nr_pages));
}
/* [start, end) must belong to a single zone. */
static int __alloc_contig_migrate_range(struct compact_control *cc,
unsigned long start, unsigned long end)
{
/* This function is based on compact_zone() from compaction.c. */
unsigned long nr_reclaimed;
unsigned long pfn = start;
unsigned int tries = 0;
int ret = 0;
migrate_prep();
while (pfn < end || !list_empty(&cc->migratepages)) {
if (fatal_signal_pending(current)) {
ret = -EINTR;
break;
}
if (list_empty(&cc->migratepages)) {
cc->nr_migratepages = 0;
pfn = isolate_migratepages_range(cc, pfn, end);
if (!pfn) {
ret = -EINTR;
break;
}
tries = 0;
} else if (++tries == 5) {
ret = ret < 0 ? ret : -EBUSY;
break;
}
nr_reclaimed = reclaim_clean_pages_from_list(cc->zone,
&cc->migratepages);
cc->nr_migratepages -= nr_reclaimed;
ret = migrate_pages(&cc->migratepages, alloc_migrate_target,
NULL, 0, cc->mode, MR_CMA);
}
if (ret < 0) {
putback_movable_pages(&cc->migratepages);
return ret;
}
return 0;
}
/**
* alloc_contig_range() -- tries to allocate given range of pages
* @start: start PFN to allocate
* @end: one-past-the-last PFN to allocate
* @migratetype: migratetype of the underlaying pageblocks (either
* #MIGRATE_MOVABLE or #MIGRATE_CMA). All pageblocks
* in range must have the same migratetype and it must
* be either of the two.
*
* The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
* aligned, however it's the caller's responsibility to guarantee that
* we are the only thread that changes migrate type of pageblocks the
* pages fall in.
*
* The PFN range must belong to a single zone.
*
* Returns zero on success or negative error code. On success all
* pages which PFN is in [start, end) are allocated for the caller and
* need to be freed with free_contig_range().
*/
int alloc_contig_range(unsigned long start, unsigned long end,
unsigned migratetype)
{
unsigned long outer_start, outer_end;
int ret = 0, order;
struct compact_control cc = {
.nr_migratepages = 0,
.order = -1,
.zone = page_zone(pfn_to_page(start)),
.mode = MIGRATE_SYNC,
.ignore_skip_hint = true,
};
INIT_LIST_HEAD(&cc.migratepages);
/*
* What we do here is we mark all pageblocks in range as
* MIGRATE_ISOLATE. Because pageblock and max order pages may
* have different sizes, and due to the way page allocator
* work, we align the range to biggest of the two pages so
* that page allocator won't try to merge buddies from
* different pageblocks and change MIGRATE_ISOLATE to some
* other migration type.
*
* Once the pageblocks are marked as MIGRATE_ISOLATE, we
* migrate the pages from an unaligned range (ie. pages that
* we are interested in). This will put all the pages in
* range back to page allocator as MIGRATE_ISOLATE.
*
* When this is done, we take the pages in range from page
* allocator removing them from the buddy system. This way
* page allocator will never consider using them.
*
* This lets us mark the pageblocks back as
* MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
* aligned range but not in the unaligned, original range are
* put back to page allocator so that buddy can use them.
*/
ret = start_isolate_page_range(pfn_max_align_down(start),
pfn_max_align_up(end), migratetype,
false);
if (ret)
return ret;
ret = __alloc_contig_migrate_range(&cc, start, end);
if (ret)
goto done;
/*
* Pages from [start, end) are within a MAX_ORDER_NR_PAGES
* aligned blocks that are marked as MIGRATE_ISOLATE. What's
* more, all pages in [start, end) are free in page allocator.
* What we are going to do is to allocate all pages from
* [start, end) (that is remove them from page allocator).
*
* The only problem is that pages at the beginning and at the
* end of interesting range may be not aligned with pages that
* page allocator holds, ie. they can be part of higher order
* pages. Because of this, we reserve the bigger range and
* once this is done free the pages we are not interested in.
*
* We don't have to hold zone->lock here because the pages are
* isolated thus they won't get removed from buddy.
*/
lru_add_drain_all();
drain_all_pages(cc.zone);
order = 0;
outer_start = start;
while (!PageBuddy(pfn_to_page(outer_start))) {
if (++order >= MAX_ORDER) {
ret = -EBUSY;
goto done;
}
outer_start &= ~0UL << order;
}
/* Make sure the range is really isolated. */
if (test_pages_isolated(outer_start, end, false)) {
pr_info("%s: [%lx, %lx) PFNs busy\n",
__func__, outer_start, end);
ret = -EBUSY;
goto done;
}
/* Grab isolated pages from freelists. */
outer_end = isolate_freepages_range(&cc, outer_start, end);
if (!outer_end) {
ret = -EBUSY;
goto done;
}
/* Free head and tail (if any) */
if (start != outer_start)
free_contig_range(outer_start, start - outer_start);
if (end != outer_end)
free_contig_range(end, outer_end - end);
done:
undo_isolate_page_range(pfn_max_align_down(start),
pfn_max_align_up(end), migratetype);
return ret;
}
void free_contig_range(unsigned long pfn, unsigned nr_pages)
{
unsigned int count = 0;
for (; nr_pages--; pfn++) {
struct page *page = pfn_to_page(pfn);
count += page_count(page) != 1;
__free_page(page);
}
WARN(count != 0, "%d pages are still in use!\n", count);
}
#endif
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* The zone indicated has a new number of managed_pages; batch sizes and percpu
* page high values need to be recalulated.
*/
void __meminit zone_pcp_update(struct zone *zone)
{
unsigned cpu;
mutex_lock(&pcp_batch_high_lock);
for_each_possible_cpu(cpu)
pageset_set_high_and_batch(zone,
per_cpu_ptr(zone->pageset, cpu));
mutex_unlock(&pcp_batch_high_lock);
}
#endif
void zone_pcp_reset(struct zone *zone)
{
unsigned long flags;
int cpu;
struct per_cpu_pageset *pset;
/* avoid races with drain_pages() */
local_irq_save(flags);
if (zone->pageset != &boot_pageset) {
for_each_online_cpu(cpu) {
pset = per_cpu_ptr(zone->pageset, cpu);
drain_zonestat(zone, pset);
}
free_percpu(zone->pageset);
zone->pageset = &boot_pageset;
}
local_irq_restore(flags);
}
#ifdef CONFIG_MEMORY_HOTREMOVE
/*
* All pages in the range must be isolated before calling this.
*/
void
__offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
{
struct page *page;
struct zone *zone;
unsigned int order, i;
unsigned long pfn;
unsigned long flags;
/* find the first valid pfn */
for (pfn = start_pfn; pfn < end_pfn; pfn++)
if (pfn_valid(pfn))
break;
if (pfn == end_pfn)
return;
zone = page_zone(pfn_to_page(pfn));
spin_lock_irqsave(&zone->lock, flags);
pfn = start_pfn;
while (pfn < end_pfn) {
if (!pfn_valid(pfn)) {
pfn++;
continue;
}
page = pfn_to_page(pfn);
/*
* The HWPoisoned page may be not in buddy system, and
* page_count() is not 0.
*/
if (unlikely(!PageBuddy(page) && PageHWPoison(page))) {
pfn++;
SetPageReserved(page);
continue;
}
BUG_ON(page_count(page));
BUG_ON(!PageBuddy(page));
order = page_order(page);
#ifdef CONFIG_DEBUG_VM
printk(KERN_INFO "remove from free list %lx %d %lx\n",
pfn, 1 << order, end_pfn);
#endif
list_del(&page->lru);
rmv_page_order(page);
zone->free_area[order].nr_free--;
for (i = 0; i < (1 << order); i++)
SetPageReserved((page+i));
pfn += (1 << order);
}
spin_unlock_irqrestore(&zone->lock, flags);
}
#endif
#ifdef CONFIG_MEMORY_FAILURE
bool is_free_buddy_page(struct page *page)
{
struct zone *zone = page_zone(page);
unsigned long pfn = page_to_pfn(page);
unsigned long flags;
unsigned int order;
spin_lock_irqsave(&zone->lock, flags);
for (order = 0; order < MAX_ORDER; order++) {
struct page *page_head = page - (pfn & ((1 << order) - 1));
if (PageBuddy(page_head) && page_order(page_head) >= order)
break;
}
spin_unlock_irqrestore(&zone->lock, flags);
return order < MAX_ORDER;
}
#endif
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