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>
21 #include <linux/vs_memory.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 struct page *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 spin_lock(&hugetlb_lock);
78 nr_huge_pages_node[page_to_nid(page)]++;
79 spin_unlock(&hugetlb_lock);
84 void free_huge_page(struct page *page)
86 BUG_ON(page_count(page));
88 INIT_LIST_HEAD(&page->lru);
89 page[1].lru.next = NULL; /* reset dtor */
91 spin_lock(&hugetlb_lock);
92 enqueue_huge_page(page);
93 spin_unlock(&hugetlb_lock);
96 struct page *alloc_huge_page(struct vm_area_struct *vma, unsigned long addr)
101 spin_lock(&hugetlb_lock);
102 page = dequeue_huge_page(vma, addr);
104 spin_unlock(&hugetlb_lock);
107 spin_unlock(&hugetlb_lock);
108 set_page_count(page, 1);
109 page[1].lru.next = (void *)free_huge_page; /* set dtor */
110 for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i)
111 clear_user_highpage(&page[i], addr);
115 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 page = alloc_fresh_huge_page();
130 spin_lock(&hugetlb_lock);
131 enqueue_huge_page(page);
132 spin_unlock(&hugetlb_lock);
134 max_huge_pages = free_huge_pages = nr_huge_pages = i;
135 printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
138 module_init(hugetlb_init);
140 static int __init hugetlb_setup(char *s)
142 if (sscanf(s, "%lu", &max_huge_pages) <= 0)
146 __setup("hugepages=", hugetlb_setup);
149 static void update_and_free_page(struct page *page)
153 nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--;
154 for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
155 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
156 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
157 1 << PG_private | 1<< PG_writeback);
158 set_page_count(&page[i], 0);
160 set_page_count(page, 1);
161 __free_pages(page, HUGETLB_PAGE_ORDER);
164 #ifdef CONFIG_HIGHMEM
165 static void try_to_free_low(unsigned long count)
168 for (i = 0; i < MAX_NUMNODES; ++i) {
169 struct page *page, *next;
170 list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
171 if (PageHighMem(page))
173 list_del(&page->lru);
174 update_and_free_page(page);
175 nid = page_zone(page)->zone_pgdat->node_id;
177 free_huge_pages_node[nid]--;
178 if (count >= nr_huge_pages)
184 static inline void try_to_free_low(unsigned long count)
189 static unsigned long set_max_huge_pages(unsigned long count)
191 while (count > nr_huge_pages) {
192 struct page *page = alloc_fresh_huge_page();
194 return nr_huge_pages;
195 spin_lock(&hugetlb_lock);
196 enqueue_huge_page(page);
197 spin_unlock(&hugetlb_lock);
199 if (count >= nr_huge_pages)
200 return nr_huge_pages;
202 spin_lock(&hugetlb_lock);
203 try_to_free_low(count);
204 while (count < nr_huge_pages) {
205 struct page *page = dequeue_huge_page(NULL, 0);
208 update_and_free_page(page);
210 spin_unlock(&hugetlb_lock);
211 return nr_huge_pages;
214 int hugetlb_sysctl_handler(struct ctl_table *table, int write,
215 struct file *file, void __user *buffer,
216 size_t *length, loff_t *ppos)
218 proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
219 max_huge_pages = set_max_huge_pages(max_huge_pages);
222 #endif /* CONFIG_SYSCTL */
224 int hugetlb_report_meminfo(char *buf)
227 "HugePages_Total: %5lu\n"
228 "HugePages_Free: %5lu\n"
229 "Hugepagesize: %5lu kB\n",
235 int hugetlb_report_node_meminfo(int nid, char *buf)
238 "Node %d HugePages_Total: %5u\n"
239 "Node %d HugePages_Free: %5u\n",
240 nid, nr_huge_pages_node[nid],
241 nid, free_huge_pages_node[nid]);
244 int is_hugepage_mem_enough(size_t size)
246 return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages;
249 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
250 unsigned long hugetlb_total_pages(void)
252 return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
256 * We cannot handle pagefaults against hugetlb pages at all. They cause
257 * handle_mm_fault() to try to instantiate regular-sized pages in the
258 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
261 static struct page *hugetlb_nopage(struct vm_area_struct *vma,
262 unsigned long address, int *unused)
268 struct vm_operations_struct hugetlb_vm_ops = {
269 .nopage = hugetlb_nopage,
272 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
279 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
281 entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
283 entry = pte_mkyoung(entry);
284 entry = pte_mkhuge(entry);
289 static void set_huge_ptep_writable(struct vm_area_struct *vma,
290 unsigned long address, pte_t *ptep)
294 entry = pte_mkwrite(pte_mkdirty(*ptep));
295 ptep_set_access_flags(vma, address, ptep, entry, 1);
296 update_mmu_cache(vma, address, entry);
297 lazy_mmu_prot_update(entry);
301 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
302 struct vm_area_struct *vma)
304 pte_t *src_pte, *dst_pte, entry;
305 struct page *ptepage;
309 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
311 for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) {
312 src_pte = huge_pte_offset(src, addr);
315 dst_pte = huge_pte_alloc(dst, addr);
318 spin_lock(&dst->page_table_lock);
319 spin_lock(&src->page_table_lock);
320 if (!pte_none(*src_pte)) {
322 ptep_set_wrprotect(src, addr, src_pte);
324 ptepage = pte_page(entry);
326 add_mm_counter(dst, file_rss, HPAGE_SIZE / PAGE_SIZE);
327 set_huge_pte_at(dst, addr, dst_pte, entry);
329 spin_unlock(&src->page_table_lock);
330 spin_unlock(&dst->page_table_lock);
338 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
341 struct mm_struct *mm = vma->vm_mm;
342 unsigned long address;
347 WARN_ON(!is_vm_hugetlb_page(vma));
348 BUG_ON(start & ~HPAGE_MASK);
349 BUG_ON(end & ~HPAGE_MASK);
351 spin_lock(&mm->page_table_lock);
353 /* Update high watermark before we lower rss */
354 update_hiwater_rss(mm);
356 for (address = start; address < end; address += HPAGE_SIZE) {
357 ptep = huge_pte_offset(mm, address);
361 pte = huge_ptep_get_and_clear(mm, address, ptep);
365 page = pte_page(pte);
367 add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE));
370 spin_unlock(&mm->page_table_lock);
371 flush_tlb_range(vma, start, end);
374 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
375 unsigned long address, pte_t *ptep, pte_t pte)
377 struct page *old_page, *new_page;
380 old_page = pte_page(pte);
382 /* If no-one else is actually using this page, avoid the copy
383 * and just make the page writable */
384 avoidcopy = (page_count(old_page) == 1);
386 set_huge_ptep_writable(vma, address, ptep);
387 return VM_FAULT_MINOR;
390 page_cache_get(old_page);
391 new_page = alloc_huge_page(vma, address);
394 page_cache_release(old_page);
398 spin_unlock(&mm->page_table_lock);
399 for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++)
400 copy_user_highpage(new_page + i, old_page + i,
401 address + i*PAGE_SIZE);
402 spin_lock(&mm->page_table_lock);
404 ptep = huge_pte_offset(mm, address & HPAGE_MASK);
405 if (likely(pte_same(*ptep, pte))) {
407 set_huge_pte_at(mm, address, ptep,
408 make_huge_pte(vma, new_page, 1));
409 /* Make the old page be freed below */
412 page_cache_release(new_page);
413 page_cache_release(old_page);
414 return VM_FAULT_MINOR;
417 int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
418 unsigned long address, pte_t *ptep, int write_access)
420 int ret = VM_FAULT_SIGBUS;
424 struct address_space *mapping;
427 mapping = vma->vm_file->f_mapping;
428 idx = ((address - vma->vm_start) >> HPAGE_SHIFT)
429 + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));
432 * Use page lock to guard against racing truncation
433 * before we get page_table_lock.
436 page = find_lock_page(mapping, idx);
438 if (hugetlb_get_quota(mapping))
440 page = alloc_huge_page(vma, address);
442 hugetlb_put_quota(mapping);
447 if (vma->vm_flags & VM_SHARED) {
450 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
453 hugetlb_put_quota(mapping);
462 spin_lock(&mm->page_table_lock);
463 size = i_size_read(mapping->host) >> HPAGE_SHIFT;
467 ret = VM_FAULT_MINOR;
468 if (!pte_none(*ptep))
471 add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE);
472 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
473 && (vma->vm_flags & VM_SHARED)));
474 set_huge_pte_at(mm, address, ptep, new_pte);
476 if (write_access && !(vma->vm_flags & VM_SHARED)) {
477 /* Optimization, do the COW without a second fault */
478 ret = hugetlb_cow(mm, vma, address, ptep, new_pte);
481 spin_unlock(&mm->page_table_lock);
487 spin_unlock(&mm->page_table_lock);
488 hugetlb_put_quota(mapping);
494 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
495 unsigned long address, int write_access)
501 ptep = huge_pte_alloc(mm, address);
507 return hugetlb_no_page(mm, vma, address, ptep, write_access);
509 ret = VM_FAULT_MINOR;
511 spin_lock(&mm->page_table_lock);
512 /* Check for a racing update before calling hugetlb_cow */
513 if (likely(pte_same(entry, *ptep)))
514 if (write_access && !pte_write(entry))
515 ret = hugetlb_cow(mm, vma, address, ptep, entry);
516 spin_unlock(&mm->page_table_lock);
521 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
522 struct page **pages, struct vm_area_struct **vmas,
523 unsigned long *position, int *length, int i)
525 unsigned long vpfn, vaddr = *position;
526 int remainder = *length;
528 vpfn = vaddr/PAGE_SIZE;
529 spin_lock(&mm->page_table_lock);
530 while (vaddr < vma->vm_end && remainder) {
535 * Some archs (sparc64, sh*) have multiple pte_ts to
536 * each hugepage. We have to make * sure we get the
537 * first, for the page indexing below to work.
539 pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);
541 if (!pte || pte_none(*pte)) {
544 spin_unlock(&mm->page_table_lock);
545 ret = hugetlb_fault(mm, vma, vaddr, 0);
546 spin_lock(&mm->page_table_lock);
547 if (ret == VM_FAULT_MINOR)
557 page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)];
570 spin_unlock(&mm->page_table_lock);