android_kernel_xiaomi_sm8350/mm/hugetlb.c
Adam Litke 4c88726597 [PATCH] hugetlb: demand fault handler
Below is a patch to implement demand faulting for huge pages.  The main
motivation for changing from prefaulting to demand faulting is so that huge
page memory areas can be allocated according to NUMA policy.

Thanks to consolidated hugetlb code, switching the behavior requires changing
only one fault handler.  The bulk of the patch just moves the logic from
hugelb_prefault() to hugetlb_pte_fault() and find_get_huge_page().

Signed-off-by: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 21:40:43 -07:00

483 lines
11 KiB
C

/*
* 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/sysctl.h>
#include <linux/highmem.h>
#include <linux/nodemask.h>
#include <linux/pagemap.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <linux/hugetlb.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,
};
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page)
{
pte_t entry;
if (vma->vm_flags & VM_WRITE) {
entry =
pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
} else {
entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
}
entry = pte_mkyoung(entry);
entry = pte_mkhuge(entry);
return entry;
}
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
struct vm_area_struct *vma)
{
pte_t *src_pte, *dst_pte, entry;
struct page *ptepage;
unsigned long addr;
for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
src_pte = huge_pte_offset(src, addr);
if (!src_pte)
continue;
dst_pte = huge_pte_alloc(dst, addr);
if (!dst_pte)
goto nomem;
spin_lock(&dst->page_table_lock);
spin_lock(&src->page_table_lock);
if (!pte_none(*src_pte)) {
entry = *src_pte;
ptepage = pte_page(entry);
get_page(ptepage);
add_mm_counter(dst, file_rss, HPAGE_SIZE / PAGE_SIZE);
set_huge_pte_at(dst, addr, dst_pte, entry);
}
spin_unlock(&src->page_table_lock);
spin_unlock(&dst->page_table_lock);
}
return 0;
nomem:
return -ENOMEM;
}
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
pte_t *ptep;
pte_t pte;
struct page *page;
WARN_ON(!is_vm_hugetlb_page(vma));
BUG_ON(start & ~HPAGE_MASK);
BUG_ON(end & ~HPAGE_MASK);
spin_lock(&mm->page_table_lock);
/* Update high watermark before we lower rss */
update_hiwater_rss(mm);
for (address = start; address < end; address += HPAGE_SIZE) {
ptep = huge_pte_offset(mm, address);
if (!ptep)
continue;
pte = huge_ptep_get_and_clear(mm, address, ptep);
if (pte_none(pte))
continue;
page = pte_page(pte);
put_page(page);
add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE));
}
spin_unlock(&mm->page_table_lock);
flush_tlb_range(vma, start, end);
}
static struct page *find_lock_huge_page(struct address_space *mapping,
unsigned long idx)
{
struct page *page;
int err;
struct inode *inode = mapping->host;
unsigned long size;
retry:
page = find_lock_page(mapping, idx);
if (page)
goto out;
/* Check to make sure the mapping hasn't been truncated */
size = i_size_read(inode) >> HPAGE_SHIFT;
if (idx >= size)
goto out;
if (hugetlb_get_quota(mapping))
goto out;
page = alloc_huge_page();
if (!page) {
hugetlb_put_quota(mapping);
goto out;
}
err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
if (err) {
put_page(page);
hugetlb_put_quota(mapping);
if (err == -EEXIST)
goto retry;
page = NULL;
}
out:
return page;
}
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, int write_access)
{
int ret = VM_FAULT_SIGBUS;
unsigned long idx;
unsigned long size;
pte_t *pte;
struct page *page;
struct address_space *mapping;
pte = huge_pte_alloc(mm, address);
if (!pte)
goto out;
mapping = vma->vm_file->f_mapping;
idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
+ (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
/*
* Use page lock to guard against racing truncation
* before we get page_table_lock.
*/
page = find_lock_huge_page(mapping, idx);
if (!page)
goto out;
spin_lock(&mm->page_table_lock);
size = i_size_read(mapping->host) >> HPAGE_SHIFT;
if (idx >= size)
goto backout;
ret = VM_FAULT_MINOR;
if (!pte_none(*pte))
goto backout;
add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE);
set_huge_pte_at(mm, address, pte, make_huge_pte(vma, page));
spin_unlock(&mm->page_table_lock);
unlock_page(page);
out:
return ret;
backout:
spin_unlock(&mm->page_table_lock);
hugetlb_put_quota(mapping);
unlock_page(page);
put_page(page);
goto out;
}
int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page **pages, struct vm_area_struct **vmas,
unsigned long *position, int *length, int i)
{
unsigned long vpfn, vaddr = *position;
int remainder = *length;
vpfn = vaddr/PAGE_SIZE;
spin_lock(&mm->page_table_lock);
while (vaddr < vma->vm_end && remainder) {
pte_t *pte;
struct page *page;
/*
* Some archs (sparc64, sh*) have multiple pte_ts to
* each hugepage. We have to make * sure we get the
* first, for the page indexing below to work.
*/
pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
if (!pte || pte_none(*pte)) {
int ret;
spin_unlock(&mm->page_table_lock);
ret = hugetlb_fault(mm, vma, vaddr, 0);
spin_lock(&mm->page_table_lock);
if (ret == VM_FAULT_MINOR)
continue;
remainder = 0;
if (!i)
i = -EFAULT;
break;
}
if (pages) {
page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
get_page(page);
pages[i] = page;
}
if (vmas)
vmas[i] = vma;
vaddr += PAGE_SIZE;
++vpfn;
--remainder;
++i;
}
spin_unlock(&mm->page_table_lock);
*length = remainder;
*position = vaddr;
return i;
}