2 * Generic hugetlb support.
3 * (C) William Irwin, April 2004
6 #include <linux/list.h>
7 #include <linux/init.h>
8 #include <linux/module.h>
10 #include <linux/sysctl.h>
11 #include <linux/highmem.h>
12 #include <linux/nodemask.h>
13 #include <linux/pagemap.h>
14 #include <linux/mempolicy.h>
15 #include <linux/cpuset.h>
18 #include <asm/pgtable.h>
20 #include <linux/hugetlb.h>
23 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
24 static unsigned long nr_huge_pages, free_huge_pages;
25 unsigned long max_huge_pages;
26 static struct list_head hugepage_freelists[MAX_NUMNODES];
27 static unsigned int nr_huge_pages_node[MAX_NUMNODES];
28 static unsigned int free_huge_pages_node[MAX_NUMNODES];
31 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
33 static DEFINE_SPINLOCK(hugetlb_lock);
35 static void enqueue_huge_page(struct page *page)
37 int nid = page_to_nid(page);
38 list_add(&page->lru, &hugepage_freelists[nid]);
40 free_huge_pages_node[nid]++;
43 static struct page *dequeue_huge_page(struct vm_area_struct *vma,
44 unsigned long address)
46 int nid = numa_node_id();
47 struct page *page = NULL;
48 struct zonelist *zonelist = huge_zonelist(vma, address);
51 for (z = zonelist->zones; *z; z++) {
52 nid = (*z)->zone_pgdat->node_id;
53 if (cpuset_zone_allowed(*z, GFP_HIGHUSER) &&
54 !list_empty(&hugepage_freelists[nid]))
59 page = list_entry(hugepage_freelists[nid].next,
63 free_huge_pages_node[nid]--;
68 static int alloc_fresh_huge_page(void)
72 page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
74 nid = (nid + 1) % num_online_nodes();
76 page[1].lru.next = (void *)free_huge_page; /* dtor */
77 spin_lock(&hugetlb_lock);
79 nr_huge_pages_node[page_to_nid(page)]++;
80 spin_unlock(&hugetlb_lock);
81 put_page(page); /* free it into the hugepage allocator */
87 void free_huge_page(struct page *page)
89 BUG_ON(page_count(page));
91 INIT_LIST_HEAD(&page->lru);
93 spin_lock(&hugetlb_lock);
94 enqueue_huge_page(page);
95 spin_unlock(&hugetlb_lock);
98 struct page *alloc_huge_page(struct vm_area_struct *vma, unsigned long addr)
103 spin_lock(&hugetlb_lock);
104 page = dequeue_huge_page(vma, addr);
106 spin_unlock(&hugetlb_lock);
109 spin_unlock(&hugetlb_lock);
110 set_page_refcounted(page);
111 for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i)
112 clear_user_highpage(&page[i], addr);
116 static int __init hugetlb_init(void)
120 if (HPAGE_SHIFT == 0)
123 for (i = 0; i < MAX_NUMNODES; ++i)
124 INIT_LIST_HEAD(&hugepage_freelists[i]);
126 for (i = 0; i < max_huge_pages; ++i) {
127 if (!alloc_fresh_huge_page())
130 max_huge_pages = free_huge_pages = nr_huge_pages = i;
131 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
134 module_init(hugetlb_init);
136 static int __init hugetlb_setup(char *s)
138 if (sscanf(s, "%lu", &max_huge_pages) <= 0)
142 __setup("hugepages=", hugetlb_setup);
145 static void update_and_free_page(struct page *page)
149 nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--;
150 for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
151 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
152 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
153 1 << PG_private | 1<< PG_writeback);
155 page[1].lru.next = NULL;
156 set_page_refcounted(page);
157 __free_pages(page, HUGETLB_PAGE_ORDER);
160 #ifdef CONFIG_HIGHMEM
161 static void try_to_free_low(unsigned long count)
164 for (i = 0; i < MAX_NUMNODES; ++i) {
165 struct page *page, *next;
166 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
167 if (PageHighMem(page))
169 list_del(&page->lru);
170 update_and_free_page(page);
171 nid = page_zone(page)->zone_pgdat->node_id;
173 free_huge_pages_node[nid]--;
174 if (count >= nr_huge_pages)
180 static inline void try_to_free_low(unsigned long count)
185 static unsigned long set_max_huge_pages(unsigned long count)
187 while (count > nr_huge_pages) {
188 if (!alloc_fresh_huge_page())
189 return nr_huge_pages;
191 if (count >= nr_huge_pages)
192 return nr_huge_pages;
194 spin_lock(&hugetlb_lock);
195 try_to_free_low(count);
196 while (count < nr_huge_pages) {
197 struct page *page = dequeue_huge_page(NULL, 0);
200 update_and_free_page(page);
202 spin_unlock(&hugetlb_lock);
203 return nr_huge_pages;
206 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
207 struct file *file, void __user *buffer,
208 size_t *length, loff_t *ppos)
210 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
211 max_huge_pages = set_max_huge_pages(max_huge_pages);
214 #endif /* CONFIG_SYSCTL */
216 int hugetlb_report_meminfo(char *buf)
219 "HugePages_Total: %5lu\n"
220 "HugePages_Free: %5lu\n"
221 "Hugepagesize: %5lu kB\n",
227 int hugetlb_report_node_meminfo(int nid, char *buf)
230 "Node %d HugePages_Total: %5u\n"
231 "Node %d HugePages_Free: %5u\n",
232 nid, nr_huge_pages_node[nid],
233 nid, free_huge_pages_node[nid]);
236 int is_hugepage_mem_enough(size_t size)
238 return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages;
241 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
242 unsigned long hugetlb_total_pages(void)
244 return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
248 * We cannot handle pagefaults against hugetlb pages at all. They cause
249 * handle_mm_fault() to try to instantiate regular-sized pages in the
250 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
253 static struct page *hugetlb_nopage(struct vm_area_struct *vma,
254 unsigned long address, int *unused)
260 struct vm_operations_struct hugetlb_vm_ops = {
261 .nopage = hugetlb_nopage,
264 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
271 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
273 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
275 entry = pte_mkyoung(entry);
276 entry = pte_mkhuge(entry);
281 static void set_huge_ptep_writable(struct vm_area_struct *vma,
282 unsigned long address, pte_t *ptep)
286 entry = pte_mkwrite(pte_mkdirty(*ptep));
287 ptep_set_access_flags(vma, address, ptep, entry, 1);
288 update_mmu_cache(vma, address, entry);
289 lazy_mmu_prot_update(entry);
293 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
294 struct vm_area_struct *vma)
296 pte_t *src_pte, *dst_pte, entry;
297 struct page *ptepage;
301 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
303 for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
304 src_pte = huge_pte_offset(src, addr);
307 dst_pte = huge_pte_alloc(dst, addr);
310 spin_lock(&dst->page_table_lock);
311 spin_lock(&src->page_table_lock);
312 if (!pte_none(*src_pte)) {
314 ptep_set_wrprotect(src, addr, src_pte);
316 ptepage = pte_page(entry);
318 add_mm_counter(dst, file_rss, HPAGE_SIZE / PAGE_SIZE);
319 set_huge_pte_at(dst, addr, dst_pte, entry);
321 spin_unlock(&src->page_table_lock);
322 spin_unlock(&dst->page_table_lock);
330 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
333 struct mm_struct *mm = vma->vm_mm;
334 unsigned long address;
339 WARN_ON(!is_vm_hugetlb_page(vma));
340 BUG_ON(start & ~HPAGE_MASK);
341 BUG_ON(end & ~HPAGE_MASK);
343 spin_lock(&mm->page_table_lock);
345 /* Update high watermark before we lower rss */
346 update_hiwater_rss(mm);
348 for (address = start; address < end; address += HPAGE_SIZE) {
349 ptep = huge_pte_offset(mm, address);
353 pte = huge_ptep_get_and_clear(mm, address, ptep);
357 page = pte_page(pte);
359 add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE));
362 spin_unlock(&mm->page_table_lock);
363 flush_tlb_range(vma, start, end);
366 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
367 unsigned long address, pte_t *ptep, pte_t pte)
369 struct page *old_page, *new_page;
372 old_page = pte_page(pte);
374 /* If no-one else is actually using this page, avoid the copy
375 * and just make the page writable */
376 avoidcopy = (page_count(old_page) == 1);
378 set_huge_ptep_writable(vma, address, ptep);
379 return VM_FAULT_MINOR;
382 page_cache_get(old_page);
383 new_page = alloc_huge_page(vma, address);
386 page_cache_release(old_page);
390 spin_unlock(&mm->page_table_lock);
391 for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++)
392 copy_user_highpage(new_page + i, old_page + i,
393 address + i*PAGE_SIZE);
394 spin_lock(&mm->page_table_lock);
396 ptep = huge_pte_offset(mm, address & HPAGE_MASK);
397 if (likely(pte_same(*ptep, pte))) {
399 set_huge_pte_at(mm, address, ptep,
400 make_huge_pte(vma, new_page, 1));
401 /* Make the old page be freed below */
404 page_cache_release(new_page);
405 page_cache_release(old_page);
406 return VM_FAULT_MINOR;
409 int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
410 unsigned long address, pte_t *ptep, int write_access)
412 int ret = VM_FAULT_SIGBUS;
416 struct address_space *mapping;
419 mapping = vma->vm_file->f_mapping;
420 idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
421 + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
424 * Use page lock to guard against racing truncation
425 * before we get page_table_lock.
428 page = find_lock_page(mapping, idx);
430 if (hugetlb_get_quota(mapping))
432 page = alloc_huge_page(vma, address);
434 hugetlb_put_quota(mapping);
439 if (vma->vm_flags & VM_SHARED) {
442 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
445 hugetlb_put_quota(mapping);
454 spin_lock(&mm->page_table_lock);
455 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
459 ret = VM_FAULT_MINOR;
460 if (!pte_none(*ptep))
463 add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE);
464 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
465 && (vma->vm_flags & VM_SHARED)));
466 set_huge_pte_at(mm, address, ptep, new_pte);
468 if (write_access && !(vma->vm_flags & VM_SHARED)) {
469 /* Optimization, do the COW without a second fault */
470 ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
473 spin_unlock(&mm->page_table_lock);
479 spin_unlock(&mm->page_table_lock);
480 hugetlb_put_quota(mapping);
486 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
487 unsigned long address, int write_access)
493 ptep = huge_pte_alloc(mm, address);
499 return hugetlb_no_page(mm, vma, address, ptep, write_access);
501 ret = VM_FAULT_MINOR;
503 spin_lock(&mm->page_table_lock);
504 /* Check for a racing update before calling hugetlb_cow */
505 if (likely(pte_same(entry, *ptep)))
506 if (write_access && !pte_write(entry))
507 ret = hugetlb_cow(mm, vma, address, ptep, entry);
508 spin_unlock(&mm->page_table_lock);
513 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
514 struct page **pages, struct vm_area_struct **vmas,
515 unsigned long *position, int *length, int i)
517 unsigned long vpfn, vaddr = *position;
518 int remainder = *length;
520 vpfn = vaddr/PAGE_SIZE;
521 spin_lock(&mm->page_table_lock);
522 while (vaddr < vma->vm_end && remainder) {
527 * Some archs (sparc64, sh*) have multiple pte_ts to
528 * each hugepage. We have to make * sure we get the
529 * first, for the page indexing below to work.
531 pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
533 if (!pte || pte_none(*pte)) {
536 spin_unlock(&mm->page_table_lock);
537 ret = hugetlb_fault(mm, vma, vaddr, 0);
538 spin_lock(&mm->page_table_lock);
539 if (ret == VM_FAULT_MINOR)
549 page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
562 spin_unlock(&mm->page_table_lock);
569 void hugetlb_change_protection(struct vm_area_struct *vma,
570 unsigned long address, unsigned long end, pgprot_t newprot)
572 struct mm_struct *mm = vma->vm_mm;
573 unsigned long start = address;
577 BUG_ON(address >= end);
578 flush_cache_range(vma, address, end);
580 spin_lock(&mm->page_table_lock);
581 for (; address < end; address += HPAGE_SIZE) {
582 ptep = huge_pte_offset(mm, address);
585 if (!pte_none(*ptep)) {
586 pte = huge_ptep_get_and_clear(mm, address, ptep);
587 pte = pte_mkhuge(pte_modify(pte, newprot));
588 set_huge_pte_at(mm, address, ptep, pte);
589 lazy_mmu_prot_update(pte);
592 spin_unlock(&mm->page_table_lock);
594 flush_tlb_range(vma, start, end);