/*
* Generic hugetlb support.
* (C) William Irwin, April 2004
*/
#include <linux/gfp.h>
#include <linux/list.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/sysctl.h>
#include <linux/highmem.h>
#include <linux/nodemask.h>
const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
static unsigned long nr_huge_pages, free_huge_pages;
unsigned long max_huge_pages;
static struct list_head hugepage_freelists[MAX_NUMNODES];
static unsigned int nr_huge_pages_node[MAX_NUMNODES];
static unsigned int free_huge_pages_node[MAX_NUMNODES];
static DEFINE_SPINLOCK(hugetlb_lock);
static void enqueue_huge_page(struct page *page)
{
int nid = page_to_nid(page);
list_add(&page->lru, &hugepage_freelists[nid]);
free_huge_pages++;
free_huge_pages_node[nid]++;
}
static struct page *dequeue_huge_page(void)
{
int nid = numa_node_id();
struct page *page = NULL;
if (list_empty(&hugepage_freelists[nid])) {
for (nid = 0; nid < MAX_NUMNODES; ++nid)
if (!list_empty(&hugepage_freelists[nid]))
break;
}
if (nid >= 0 && nid < MAX_NUMNODES &&
!list_empty(&hugepage_freelists[nid])) {
page = list_entry(hugepage_freelists[nid].next,
struct page, lru);
list_del(&page->lru);
free_huge_pages--;
free_huge_pages_node[nid]--;
}
return page;
}
static struct page *alloc_fresh_huge_page(void)
{
static int nid = 0;
struct page *page;
page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
HUGETLB_PAGE_ORDER);
nid = (nid + 1) % num_online_nodes();
if (page) {
nr_huge_pages++;
nr_huge_pages_node[page_to_nid(page)]++;
}
return page;
}
void free_huge_page(struct page *page)
{
BUG_ON(page_count(page));
INIT_LIST_HEAD(&page->lru);
page[1].mapping = NULL;
spin_lock(&hugetlb_lock);
enqueue_huge_page(page);
spin_unlock(&hugetlb_lock);
}
struct page *alloc_huge_page(void)
{
struct page *page;
int i;
spin_lock(&hugetlb_lock);
page = dequeue_huge_page();
if (!page) {
spin_unlock(&hugetlb_lock);
return NULL;
}
spin_unlock(&hugetlb_lock);
set_page_count(page, 1);
page[1].mapping = (void *)free_huge_page;
for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i)
clear_highpage(&page[i]);
return page;
}
static int __init hugetlb_init(void)
{
unsigned long i;
struct page *page;
for (i = 0; i < MAX_NUMNODES; ++i)
INIT_LIST_HEAD(&hugepage_freelists[i]);
for (i = 0; i < max_huge_pages; ++i) {
page = alloc_fresh_huge_page();
if (!page)
break;
spin_lock(&hugetlb_lock);
enqueue_huge_page(page);
spin_unlock(&hugetlb_lock);
}
max_huge_pages = free_huge_pages = nr_huge_pages = i;
printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
return 0;
}
module_init(hugetlb_init);
static int __init hugetlb_setup(char *s)
{
if (sscanf(s, "%lu", &max_huge_pages) <= 0)
max_huge_pages = 0;
return 1;
}
__setup("hugepages=", hugetlb_setup);
#ifdef CONFIG_SYSCTL
static void update_and_free_page(struct page *page)
{
int i;
nr_huge_pages--;
nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--;
for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
1 << PG_private | 1<< PG_writeback);
set_page_count(&page[i], 0);
}
set_page_count(page, 1);
__free_pages(page, HUGETLB_PAGE_ORDER);
}
#ifdef CONFIG_HIGHMEM
static void try_to_free_low(unsigned long count)
{
int i, nid;
for (i = 0; i < MAX_NUMNODES; ++i) {
struct page *page, *next;
list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
if (PageHighMem(page))
continue;
list_del(&page->lru);
update_and_free_page(page);
nid = page_zone(page)->zone_pgdat->node_id;
free_huge_pages--;
free_huge_pages_node[nid]--;
if (count >= nr_huge_pages)
return;
}
}
}
#else
static inline void try_to_free_low(unsigned long count)
{
}
#endif
static unsigned long set_max_huge_pages(unsigned long count)
{
while (count > nr_huge_pages) {
struct page *page = alloc_fresh_huge_page();
if (!page)
return nr_huge_pages;
spin_lock(&hugetlb_lock);
enqueue_huge_page(page);
spin_unlock(&hugetlb_lock);
}
if (count >= nr_huge_pages)
return nr_huge_pages;
spin_lock(&hugetlb_lock);
try_to_free_low(count);
while (count < nr_huge_pages) {
struct page *page = dequeue_huge_page();
if (!page)
break;
update_and_free_page(page);
}
spin_unlock(&hugetlb_lock);
return nr_huge_pages;
}
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
struct file *file, void __user *buffer,
size_t *length, loff_t *ppos)
{
proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
max_huge_pages = set_max_huge_pages(max_huge_pages);
return 0;
}
#endif /* CONFIG_SYSCTL */
int hugetlb_report_meminfo(char *buf)
{
return sprintf(buf,
"HugePages_Total: %5lu\n"
"HugePages_Free: %5lu\n"
"Hugepagesize: %5lu kB\n",
nr_huge_pages,
free_huge_pages,
HPAGE_SIZE/1024);
}
int hugetlb_report_node_meminfo(int nid, char *buf)
{
return sprintf(buf,
"Node %d HugePages_Total: %5u\n"
"Node %d HugePages_Free: %5u\n",
nid, nr_huge_pages_node[nid],
nid, free_huge_pages_node[nid]);
}
int is_hugepage_mem_enough(size_t size)
{
return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages;
}
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
}
EXPORT_SYMBOL(hugetlb_total_pages);
/*
* We cannot handle pagefaults against hugetlb pages at all. They cause
* handle_mm_fault() to try to instantiate regular-sized pages in the
* hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
* this far.
*/
static struct page *hugetlb_nopage(struct vm_area_struct *vma,
unsigned long address, int *unused)
{
BUG();
return NULL;
}
struct vm_operations_struct hugetlb_vm_ops = {
.nopage = hugetlb_nopage,
};
void zap_hugepage_range(struct vm_area_struct *vma,
unsigned long start, unsigned long length)
{
struct mm_struct *mm = vma->vm_mm;
spin_lock(&mm->page_table_lock);
unmap_hugepage_range(vma, start, start + length);
spin_unlock(&mm->page_table_lock);
}
