Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Generic hugetlb support. | |
3 | * (C) William Irwin, April 2004 | |
4 | */ | |
5 | #include <linux/gfp.h> | |
6 | #include <linux/list.h> | |
7 | #include <linux/init.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/mm.h> | |
1da177e4 LT |
10 | #include <linux/sysctl.h> |
11 | #include <linux/highmem.h> | |
12 | #include <linux/nodemask.h> | |
63551ae0 | 13 | #include <linux/pagemap.h> |
5da7ca86 | 14 | #include <linux/mempolicy.h> |
aea47ff3 | 15 | #include <linux/cpuset.h> |
3935baa9 | 16 | #include <linux/mutex.h> |
5da7ca86 | 17 | |
63551ae0 DG |
18 | #include <asm/page.h> |
19 | #include <asm/pgtable.h> | |
20 | ||
21 | #include <linux/hugetlb.h> | |
7835e98b | 22 | #include "internal.h" |
1da177e4 LT |
23 | |
24 | const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; | |
a43a8c39 | 25 | static unsigned long nr_huge_pages, free_huge_pages, resv_huge_pages; |
1da177e4 LT |
26 | unsigned long max_huge_pages; |
27 | static struct list_head hugepage_freelists[MAX_NUMNODES]; | |
28 | static unsigned int nr_huge_pages_node[MAX_NUMNODES]; | |
29 | static unsigned int free_huge_pages_node[MAX_NUMNODES]; | |
3935baa9 DG |
30 | /* |
31 | * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages | |
32 | */ | |
33 | static DEFINE_SPINLOCK(hugetlb_lock); | |
0bd0f9fb | 34 | |
79ac6ba4 DG |
35 | static void clear_huge_page(struct page *page, unsigned long addr) |
36 | { | |
37 | int i; | |
38 | ||
39 | might_sleep(); | |
40 | for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) { | |
41 | cond_resched(); | |
42 | clear_user_highpage(page + i, addr); | |
43 | } | |
44 | } | |
45 | ||
46 | static void copy_huge_page(struct page *dst, struct page *src, | |
9de455b2 | 47 | unsigned long addr, struct vm_area_struct *vma) |
79ac6ba4 DG |
48 | { |
49 | int i; | |
50 | ||
51 | might_sleep(); | |
52 | for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) { | |
53 | cond_resched(); | |
9de455b2 | 54 | copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); |
79ac6ba4 DG |
55 | } |
56 | } | |
57 | ||
1da177e4 LT |
58 | static void enqueue_huge_page(struct page *page) |
59 | { | |
60 | int nid = page_to_nid(page); | |
61 | list_add(&page->lru, &hugepage_freelists[nid]); | |
62 | free_huge_pages++; | |
63 | free_huge_pages_node[nid]++; | |
64 | } | |
65 | ||
5da7ca86 CL |
66 | static struct page *dequeue_huge_page(struct vm_area_struct *vma, |
67 | unsigned long address) | |
1da177e4 | 68 | { |
31a5c6e4 | 69 | int nid; |
1da177e4 | 70 | struct page *page = NULL; |
5da7ca86 | 71 | struct zonelist *zonelist = huge_zonelist(vma, address); |
96df9333 | 72 | struct zone **z; |
1da177e4 | 73 | |
96df9333 | 74 | for (z = zonelist->zones; *z; z++) { |
89fa3024 | 75 | nid = zone_to_nid(*z); |
02a0e53d | 76 | if (cpuset_zone_allowed_softwall(*z, GFP_HIGHUSER) && |
aea47ff3 | 77 | !list_empty(&hugepage_freelists[nid])) |
96df9333 | 78 | break; |
1da177e4 | 79 | } |
96df9333 CL |
80 | |
81 | if (*z) { | |
1da177e4 LT |
82 | page = list_entry(hugepage_freelists[nid].next, |
83 | struct page, lru); | |
84 | list_del(&page->lru); | |
85 | free_huge_pages--; | |
86 | free_huge_pages_node[nid]--; | |
87 | } | |
88 | return page; | |
89 | } | |
90 | ||
27a85ef1 DG |
91 | static void free_huge_page(struct page *page) |
92 | { | |
93 | BUG_ON(page_count(page)); | |
94 | ||
95 | INIT_LIST_HEAD(&page->lru); | |
96 | ||
97 | spin_lock(&hugetlb_lock); | |
98 | enqueue_huge_page(page); | |
99 | spin_unlock(&hugetlb_lock); | |
100 | } | |
101 | ||
a482289d | 102 | static int alloc_fresh_huge_page(void) |
1da177e4 | 103 | { |
f96efd58 | 104 | static int prev_nid; |
1da177e4 | 105 | struct page *page; |
f96efd58 JJ |
106 | static DEFINE_SPINLOCK(nid_lock); |
107 | int nid; | |
108 | ||
109 | spin_lock(&nid_lock); | |
110 | nid = next_node(prev_nid, node_online_map); | |
fdb7cc59 PJ |
111 | if (nid == MAX_NUMNODES) |
112 | nid = first_node(node_online_map); | |
f96efd58 JJ |
113 | prev_nid = nid; |
114 | spin_unlock(&nid_lock); | |
115 | ||
116 | page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN, | |
117 | HUGETLB_PAGE_ORDER); | |
1da177e4 | 118 | if (page) { |
33f2ef89 | 119 | set_compound_page_dtor(page, free_huge_page); |
0bd0f9fb | 120 | spin_lock(&hugetlb_lock); |
1da177e4 LT |
121 | nr_huge_pages++; |
122 | nr_huge_pages_node[page_to_nid(page)]++; | |
0bd0f9fb | 123 | spin_unlock(&hugetlb_lock); |
a482289d NP |
124 | put_page(page); /* free it into the hugepage allocator */ |
125 | return 1; | |
1da177e4 | 126 | } |
a482289d | 127 | return 0; |
1da177e4 LT |
128 | } |
129 | ||
27a85ef1 DG |
130 | static struct page *alloc_huge_page(struct vm_area_struct *vma, |
131 | unsigned long addr) | |
1da177e4 LT |
132 | { |
133 | struct page *page; | |
1da177e4 LT |
134 | |
135 | spin_lock(&hugetlb_lock); | |
a43a8c39 CK |
136 | if (vma->vm_flags & VM_MAYSHARE) |
137 | resv_huge_pages--; | |
138 | else if (free_huge_pages <= resv_huge_pages) | |
139 | goto fail; | |
b45b5bd6 DG |
140 | |
141 | page = dequeue_huge_page(vma, addr); | |
142 | if (!page) | |
143 | goto fail; | |
144 | ||
1da177e4 | 145 | spin_unlock(&hugetlb_lock); |
7835e98b | 146 | set_page_refcounted(page); |
1da177e4 | 147 | return page; |
b45b5bd6 | 148 | |
a43a8c39 | 149 | fail: |
ace4bd29 KC |
150 | if (vma->vm_flags & VM_MAYSHARE) |
151 | resv_huge_pages++; | |
b45b5bd6 DG |
152 | spin_unlock(&hugetlb_lock); |
153 | return NULL; | |
154 | } | |
155 | ||
1da177e4 LT |
156 | static int __init hugetlb_init(void) |
157 | { | |
158 | unsigned long i; | |
1da177e4 | 159 | |
3c726f8d BH |
160 | if (HPAGE_SHIFT == 0) |
161 | return 0; | |
162 | ||
1da177e4 LT |
163 | for (i = 0; i < MAX_NUMNODES; ++i) |
164 | INIT_LIST_HEAD(&hugepage_freelists[i]); | |
165 | ||
166 | for (i = 0; i < max_huge_pages; ++i) { | |
a482289d | 167 | if (!alloc_fresh_huge_page()) |
1da177e4 | 168 | break; |
1da177e4 LT |
169 | } |
170 | max_huge_pages = free_huge_pages = nr_huge_pages = i; | |
171 | printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); | |
172 | return 0; | |
173 | } | |
174 | module_init(hugetlb_init); | |
175 | ||
176 | static int __init hugetlb_setup(char *s) | |
177 | { | |
178 | if (sscanf(s, "%lu", &max_huge_pages) <= 0) | |
179 | max_huge_pages = 0; | |
180 | return 1; | |
181 | } | |
182 | __setup("hugepages=", hugetlb_setup); | |
183 | ||
8a630112 KC |
184 | static unsigned int cpuset_mems_nr(unsigned int *array) |
185 | { | |
186 | int node; | |
187 | unsigned int nr = 0; | |
188 | ||
189 | for_each_node_mask(node, cpuset_current_mems_allowed) | |
190 | nr += array[node]; | |
191 | ||
192 | return nr; | |
193 | } | |
194 | ||
1da177e4 LT |
195 | #ifdef CONFIG_SYSCTL |
196 | static void update_and_free_page(struct page *page) | |
197 | { | |
198 | int i; | |
199 | nr_huge_pages--; | |
4415cc8d | 200 | nr_huge_pages_node[page_to_nid(page)]--; |
1da177e4 LT |
201 | for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) { |
202 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | | |
203 | 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | | |
204 | 1 << PG_private | 1<< PG_writeback); | |
1da177e4 | 205 | } |
a482289d | 206 | page[1].lru.next = NULL; |
7835e98b | 207 | set_page_refcounted(page); |
1da177e4 LT |
208 | __free_pages(page, HUGETLB_PAGE_ORDER); |
209 | } | |
210 | ||
211 | #ifdef CONFIG_HIGHMEM | |
212 | static void try_to_free_low(unsigned long count) | |
213 | { | |
4415cc8d CL |
214 | int i; |
215 | ||
1da177e4 LT |
216 | for (i = 0; i < MAX_NUMNODES; ++i) { |
217 | struct page *page, *next; | |
218 | list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) { | |
219 | if (PageHighMem(page)) | |
220 | continue; | |
221 | list_del(&page->lru); | |
222 | update_and_free_page(page); | |
1da177e4 | 223 | free_huge_pages--; |
4415cc8d | 224 | free_huge_pages_node[page_to_nid(page)]--; |
1da177e4 LT |
225 | if (count >= nr_huge_pages) |
226 | return; | |
227 | } | |
228 | } | |
229 | } | |
230 | #else | |
231 | static inline void try_to_free_low(unsigned long count) | |
232 | { | |
233 | } | |
234 | #endif | |
235 | ||
236 | static unsigned long set_max_huge_pages(unsigned long count) | |
237 | { | |
238 | while (count > nr_huge_pages) { | |
a482289d | 239 | if (!alloc_fresh_huge_page()) |
1da177e4 | 240 | return nr_huge_pages; |
1da177e4 LT |
241 | } |
242 | if (count >= nr_huge_pages) | |
243 | return nr_huge_pages; | |
244 | ||
245 | spin_lock(&hugetlb_lock); | |
a43a8c39 | 246 | count = max(count, resv_huge_pages); |
1da177e4 LT |
247 | try_to_free_low(count); |
248 | while (count < nr_huge_pages) { | |
5da7ca86 | 249 | struct page *page = dequeue_huge_page(NULL, 0); |
1da177e4 LT |
250 | if (!page) |
251 | break; | |
252 | update_and_free_page(page); | |
253 | } | |
254 | spin_unlock(&hugetlb_lock); | |
255 | return nr_huge_pages; | |
256 | } | |
257 | ||
258 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, | |
259 | struct file *file, void __user *buffer, | |
260 | size_t *length, loff_t *ppos) | |
261 | { | |
262 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); | |
263 | max_huge_pages = set_max_huge_pages(max_huge_pages); | |
264 | return 0; | |
265 | } | |
266 | #endif /* CONFIG_SYSCTL */ | |
267 | ||
268 | int hugetlb_report_meminfo(char *buf) | |
269 | { | |
270 | return sprintf(buf, | |
271 | "HugePages_Total: %5lu\n" | |
272 | "HugePages_Free: %5lu\n" | |
a43a8c39 | 273 | "HugePages_Rsvd: %5lu\n" |
1da177e4 LT |
274 | "Hugepagesize: %5lu kB\n", |
275 | nr_huge_pages, | |
276 | free_huge_pages, | |
a43a8c39 | 277 | resv_huge_pages, |
1da177e4 LT |
278 | HPAGE_SIZE/1024); |
279 | } | |
280 | ||
281 | int hugetlb_report_node_meminfo(int nid, char *buf) | |
282 | { | |
283 | return sprintf(buf, | |
284 | "Node %d HugePages_Total: %5u\n" | |
285 | "Node %d HugePages_Free: %5u\n", | |
286 | nid, nr_huge_pages_node[nid], | |
287 | nid, free_huge_pages_node[nid]); | |
288 | } | |
289 | ||
1da177e4 LT |
290 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
291 | unsigned long hugetlb_total_pages(void) | |
292 | { | |
293 | return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE); | |
294 | } | |
1da177e4 LT |
295 | |
296 | /* | |
297 | * We cannot handle pagefaults against hugetlb pages at all. They cause | |
298 | * handle_mm_fault() to try to instantiate regular-sized pages in the | |
299 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get | |
300 | * this far. | |
301 | */ | |
302 | static struct page *hugetlb_nopage(struct vm_area_struct *vma, | |
303 | unsigned long address, int *unused) | |
304 | { | |
305 | BUG(); | |
306 | return NULL; | |
307 | } | |
308 | ||
309 | struct vm_operations_struct hugetlb_vm_ops = { | |
310 | .nopage = hugetlb_nopage, | |
311 | }; | |
312 | ||
1e8f889b DG |
313 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
314 | int writable) | |
63551ae0 DG |
315 | { |
316 | pte_t entry; | |
317 | ||
1e8f889b | 318 | if (writable) { |
63551ae0 DG |
319 | entry = |
320 | pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); | |
321 | } else { | |
322 | entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot)); | |
323 | } | |
324 | entry = pte_mkyoung(entry); | |
325 | entry = pte_mkhuge(entry); | |
326 | ||
327 | return entry; | |
328 | } | |
329 | ||
1e8f889b DG |
330 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
331 | unsigned long address, pte_t *ptep) | |
332 | { | |
333 | pte_t entry; | |
334 | ||
335 | entry = pte_mkwrite(pte_mkdirty(*ptep)); | |
8dab5241 BH |
336 | if (ptep_set_access_flags(vma, address, ptep, entry, 1)) { |
337 | update_mmu_cache(vma, address, entry); | |
338 | lazy_mmu_prot_update(entry); | |
339 | } | |
1e8f889b DG |
340 | } |
341 | ||
342 | ||
63551ae0 DG |
343 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
344 | struct vm_area_struct *vma) | |
345 | { | |
346 | pte_t *src_pte, *dst_pte, entry; | |
347 | struct page *ptepage; | |
1c59827d | 348 | unsigned long addr; |
1e8f889b DG |
349 | int cow; |
350 | ||
351 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
63551ae0 | 352 | |
1c59827d | 353 | for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
c74df32c HD |
354 | src_pte = huge_pte_offset(src, addr); |
355 | if (!src_pte) | |
356 | continue; | |
63551ae0 DG |
357 | dst_pte = huge_pte_alloc(dst, addr); |
358 | if (!dst_pte) | |
359 | goto nomem; | |
c74df32c | 360 | spin_lock(&dst->page_table_lock); |
1c59827d | 361 | spin_lock(&src->page_table_lock); |
c74df32c | 362 | if (!pte_none(*src_pte)) { |
1e8f889b DG |
363 | if (cow) |
364 | ptep_set_wrprotect(src, addr, src_pte); | |
1c59827d HD |
365 | entry = *src_pte; |
366 | ptepage = pte_page(entry); | |
367 | get_page(ptepage); | |
1c59827d HD |
368 | set_huge_pte_at(dst, addr, dst_pte, entry); |
369 | } | |
370 | spin_unlock(&src->page_table_lock); | |
c74df32c | 371 | spin_unlock(&dst->page_table_lock); |
63551ae0 DG |
372 | } |
373 | return 0; | |
374 | ||
375 | nomem: | |
376 | return -ENOMEM; | |
377 | } | |
378 | ||
502717f4 CK |
379 | void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
380 | unsigned long end) | |
63551ae0 DG |
381 | { |
382 | struct mm_struct *mm = vma->vm_mm; | |
383 | unsigned long address; | |
c7546f8f | 384 | pte_t *ptep; |
63551ae0 DG |
385 | pte_t pte; |
386 | struct page *page; | |
fe1668ae | 387 | struct page *tmp; |
c0a499c2 CK |
388 | /* |
389 | * A page gathering list, protected by per file i_mmap_lock. The | |
390 | * lock is used to avoid list corruption from multiple unmapping | |
391 | * of the same page since we are using page->lru. | |
392 | */ | |
fe1668ae | 393 | LIST_HEAD(page_list); |
63551ae0 DG |
394 | |
395 | WARN_ON(!is_vm_hugetlb_page(vma)); | |
396 | BUG_ON(start & ~HPAGE_MASK); | |
397 | BUG_ON(end & ~HPAGE_MASK); | |
398 | ||
508034a3 | 399 | spin_lock(&mm->page_table_lock); |
63551ae0 | 400 | for (address = start; address < end; address += HPAGE_SIZE) { |
c7546f8f | 401 | ptep = huge_pte_offset(mm, address); |
4c887265 | 402 | if (!ptep) |
c7546f8f DG |
403 | continue; |
404 | ||
39dde65c CK |
405 | if (huge_pmd_unshare(mm, &address, ptep)) |
406 | continue; | |
407 | ||
c7546f8f | 408 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
63551ae0 DG |
409 | if (pte_none(pte)) |
410 | continue; | |
c7546f8f | 411 | |
63551ae0 | 412 | page = pte_page(pte); |
6649a386 KC |
413 | if (pte_dirty(pte)) |
414 | set_page_dirty(page); | |
fe1668ae | 415 | list_add(&page->lru, &page_list); |
63551ae0 | 416 | } |
1da177e4 | 417 | spin_unlock(&mm->page_table_lock); |
508034a3 | 418 | flush_tlb_range(vma, start, end); |
fe1668ae CK |
419 | list_for_each_entry_safe(page, tmp, &page_list, lru) { |
420 | list_del(&page->lru); | |
421 | put_page(page); | |
422 | } | |
1da177e4 | 423 | } |
63551ae0 | 424 | |
502717f4 CK |
425 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
426 | unsigned long end) | |
427 | { | |
428 | /* | |
429 | * It is undesirable to test vma->vm_file as it should be non-null | |
430 | * for valid hugetlb area. However, vm_file will be NULL in the error | |
431 | * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails, | |
432 | * do_mmap_pgoff() nullifies vma->vm_file before calling this function | |
433 | * to clean up. Since no pte has actually been setup, it is safe to | |
434 | * do nothing in this case. | |
435 | */ | |
436 | if (vma->vm_file) { | |
437 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); | |
438 | __unmap_hugepage_range(vma, start, end); | |
439 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); | |
440 | } | |
441 | } | |
442 | ||
1e8f889b DG |
443 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
444 | unsigned long address, pte_t *ptep, pte_t pte) | |
445 | { | |
446 | struct page *old_page, *new_page; | |
79ac6ba4 | 447 | int avoidcopy; |
1e8f889b DG |
448 | |
449 | old_page = pte_page(pte); | |
450 | ||
451 | /* If no-one else is actually using this page, avoid the copy | |
452 | * and just make the page writable */ | |
453 | avoidcopy = (page_count(old_page) == 1); | |
454 | if (avoidcopy) { | |
455 | set_huge_ptep_writable(vma, address, ptep); | |
456 | return VM_FAULT_MINOR; | |
457 | } | |
458 | ||
459 | page_cache_get(old_page); | |
5da7ca86 | 460 | new_page = alloc_huge_page(vma, address); |
1e8f889b DG |
461 | |
462 | if (!new_page) { | |
463 | page_cache_release(old_page); | |
0df420d8 | 464 | return VM_FAULT_OOM; |
1e8f889b DG |
465 | } |
466 | ||
467 | spin_unlock(&mm->page_table_lock); | |
9de455b2 | 468 | copy_huge_page(new_page, old_page, address, vma); |
1e8f889b DG |
469 | spin_lock(&mm->page_table_lock); |
470 | ||
471 | ptep = huge_pte_offset(mm, address & HPAGE_MASK); | |
472 | if (likely(pte_same(*ptep, pte))) { | |
473 | /* Break COW */ | |
474 | set_huge_pte_at(mm, address, ptep, | |
475 | make_huge_pte(vma, new_page, 1)); | |
476 | /* Make the old page be freed below */ | |
477 | new_page = old_page; | |
478 | } | |
479 | page_cache_release(new_page); | |
480 | page_cache_release(old_page); | |
481 | return VM_FAULT_MINOR; | |
482 | } | |
483 | ||
86e5216f | 484 | int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1e8f889b | 485 | unsigned long address, pte_t *ptep, int write_access) |
ac9b9c66 HD |
486 | { |
487 | int ret = VM_FAULT_SIGBUS; | |
4c887265 AL |
488 | unsigned long idx; |
489 | unsigned long size; | |
4c887265 AL |
490 | struct page *page; |
491 | struct address_space *mapping; | |
1e8f889b | 492 | pte_t new_pte; |
4c887265 | 493 | |
4c887265 AL |
494 | mapping = vma->vm_file->f_mapping; |
495 | idx = ((address - vma->vm_start) >> HPAGE_SHIFT) | |
496 | + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); | |
497 | ||
498 | /* | |
499 | * Use page lock to guard against racing truncation | |
500 | * before we get page_table_lock. | |
501 | */ | |
6bda666a CL |
502 | retry: |
503 | page = find_lock_page(mapping, idx); | |
504 | if (!page) { | |
ebed4bfc HD |
505 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
506 | if (idx >= size) | |
507 | goto out; | |
6bda666a CL |
508 | if (hugetlb_get_quota(mapping)) |
509 | goto out; | |
510 | page = alloc_huge_page(vma, address); | |
511 | if (!page) { | |
512 | hugetlb_put_quota(mapping); | |
0df420d8 | 513 | ret = VM_FAULT_OOM; |
6bda666a CL |
514 | goto out; |
515 | } | |
79ac6ba4 | 516 | clear_huge_page(page, address); |
ac9b9c66 | 517 | |
6bda666a CL |
518 | if (vma->vm_flags & VM_SHARED) { |
519 | int err; | |
520 | ||
521 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); | |
522 | if (err) { | |
523 | put_page(page); | |
524 | hugetlb_put_quota(mapping); | |
525 | if (err == -EEXIST) | |
526 | goto retry; | |
527 | goto out; | |
528 | } | |
529 | } else | |
530 | lock_page(page); | |
531 | } | |
1e8f889b | 532 | |
ac9b9c66 | 533 | spin_lock(&mm->page_table_lock); |
4c887265 AL |
534 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
535 | if (idx >= size) | |
536 | goto backout; | |
537 | ||
538 | ret = VM_FAULT_MINOR; | |
86e5216f | 539 | if (!pte_none(*ptep)) |
4c887265 AL |
540 | goto backout; |
541 | ||
1e8f889b DG |
542 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
543 | && (vma->vm_flags & VM_SHARED))); | |
544 | set_huge_pte_at(mm, address, ptep, new_pte); | |
545 | ||
546 | if (write_access && !(vma->vm_flags & VM_SHARED)) { | |
547 | /* Optimization, do the COW without a second fault */ | |
548 | ret = hugetlb_cow(mm, vma, address, ptep, new_pte); | |
549 | } | |
550 | ||
ac9b9c66 | 551 | spin_unlock(&mm->page_table_lock); |
4c887265 AL |
552 | unlock_page(page); |
553 | out: | |
ac9b9c66 | 554 | return ret; |
4c887265 AL |
555 | |
556 | backout: | |
557 | spin_unlock(&mm->page_table_lock); | |
558 | hugetlb_put_quota(mapping); | |
559 | unlock_page(page); | |
560 | put_page(page); | |
561 | goto out; | |
ac9b9c66 HD |
562 | } |
563 | ||
86e5216f AL |
564 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
565 | unsigned long address, int write_access) | |
566 | { | |
567 | pte_t *ptep; | |
568 | pte_t entry; | |
1e8f889b | 569 | int ret; |
3935baa9 | 570 | static DEFINE_MUTEX(hugetlb_instantiation_mutex); |
86e5216f AL |
571 | |
572 | ptep = huge_pte_alloc(mm, address); | |
573 | if (!ptep) | |
574 | return VM_FAULT_OOM; | |
575 | ||
3935baa9 DG |
576 | /* |
577 | * Serialize hugepage allocation and instantiation, so that we don't | |
578 | * get spurious allocation failures if two CPUs race to instantiate | |
579 | * the same page in the page cache. | |
580 | */ | |
581 | mutex_lock(&hugetlb_instantiation_mutex); | |
86e5216f | 582 | entry = *ptep; |
3935baa9 DG |
583 | if (pte_none(entry)) { |
584 | ret = hugetlb_no_page(mm, vma, address, ptep, write_access); | |
585 | mutex_unlock(&hugetlb_instantiation_mutex); | |
586 | return ret; | |
587 | } | |
86e5216f | 588 | |
1e8f889b DG |
589 | ret = VM_FAULT_MINOR; |
590 | ||
591 | spin_lock(&mm->page_table_lock); | |
592 | /* Check for a racing update before calling hugetlb_cow */ | |
593 | if (likely(pte_same(entry, *ptep))) | |
594 | if (write_access && !pte_write(entry)) | |
595 | ret = hugetlb_cow(mm, vma, address, ptep, entry); | |
596 | spin_unlock(&mm->page_table_lock); | |
3935baa9 | 597 | mutex_unlock(&hugetlb_instantiation_mutex); |
1e8f889b DG |
598 | |
599 | return ret; | |
86e5216f AL |
600 | } |
601 | ||
63551ae0 DG |
602 | int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
603 | struct page **pages, struct vm_area_struct **vmas, | |
604 | unsigned long *position, int *length, int i) | |
605 | { | |
d5d4b0aa CK |
606 | unsigned long pfn_offset; |
607 | unsigned long vaddr = *position; | |
63551ae0 DG |
608 | int remainder = *length; |
609 | ||
1c59827d | 610 | spin_lock(&mm->page_table_lock); |
63551ae0 | 611 | while (vaddr < vma->vm_end && remainder) { |
4c887265 AL |
612 | pte_t *pte; |
613 | struct page *page; | |
63551ae0 | 614 | |
4c887265 AL |
615 | /* |
616 | * Some archs (sparc64, sh*) have multiple pte_ts to | |
617 | * each hugepage. We have to make * sure we get the | |
618 | * first, for the page indexing below to work. | |
619 | */ | |
620 | pte = huge_pte_offset(mm, vaddr & HPAGE_MASK); | |
63551ae0 | 621 | |
4c887265 AL |
622 | if (!pte || pte_none(*pte)) { |
623 | int ret; | |
63551ae0 | 624 | |
4c887265 AL |
625 | spin_unlock(&mm->page_table_lock); |
626 | ret = hugetlb_fault(mm, vma, vaddr, 0); | |
627 | spin_lock(&mm->page_table_lock); | |
628 | if (ret == VM_FAULT_MINOR) | |
629 | continue; | |
63551ae0 | 630 | |
4c887265 AL |
631 | remainder = 0; |
632 | if (!i) | |
633 | i = -EFAULT; | |
634 | break; | |
635 | } | |
636 | ||
d5d4b0aa CK |
637 | pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT; |
638 | page = pte_page(*pte); | |
639 | same_page: | |
d6692183 CK |
640 | if (pages) { |
641 | get_page(page); | |
d5d4b0aa | 642 | pages[i] = page + pfn_offset; |
d6692183 | 643 | } |
63551ae0 DG |
644 | |
645 | if (vmas) | |
646 | vmas[i] = vma; | |
647 | ||
648 | vaddr += PAGE_SIZE; | |
d5d4b0aa | 649 | ++pfn_offset; |
63551ae0 DG |
650 | --remainder; |
651 | ++i; | |
d5d4b0aa CK |
652 | if (vaddr < vma->vm_end && remainder && |
653 | pfn_offset < HPAGE_SIZE/PAGE_SIZE) { | |
654 | /* | |
655 | * We use pfn_offset to avoid touching the pageframes | |
656 | * of this compound page. | |
657 | */ | |
658 | goto same_page; | |
659 | } | |
63551ae0 | 660 | } |
1c59827d | 661 | spin_unlock(&mm->page_table_lock); |
63551ae0 DG |
662 | *length = remainder; |
663 | *position = vaddr; | |
664 | ||
665 | return i; | |
666 | } | |
8f860591 ZY |
667 | |
668 | void hugetlb_change_protection(struct vm_area_struct *vma, | |
669 | unsigned long address, unsigned long end, pgprot_t newprot) | |
670 | { | |
671 | struct mm_struct *mm = vma->vm_mm; | |
672 | unsigned long start = address; | |
673 | pte_t *ptep; | |
674 | pte_t pte; | |
675 | ||
676 | BUG_ON(address >= end); | |
677 | flush_cache_range(vma, address, end); | |
678 | ||
39dde65c | 679 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
680 | spin_lock(&mm->page_table_lock); |
681 | for (; address < end; address += HPAGE_SIZE) { | |
682 | ptep = huge_pte_offset(mm, address); | |
683 | if (!ptep) | |
684 | continue; | |
39dde65c CK |
685 | if (huge_pmd_unshare(mm, &address, ptep)) |
686 | continue; | |
8f860591 ZY |
687 | if (!pte_none(*ptep)) { |
688 | pte = huge_ptep_get_and_clear(mm, address, ptep); | |
689 | pte = pte_mkhuge(pte_modify(pte, newprot)); | |
690 | set_huge_pte_at(mm, address, ptep, pte); | |
691 | lazy_mmu_prot_update(pte); | |
692 | } | |
693 | } | |
694 | spin_unlock(&mm->page_table_lock); | |
39dde65c | 695 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
696 | |
697 | flush_tlb_range(vma, start, end); | |
698 | } | |
699 | ||
a43a8c39 CK |
700 | struct file_region { |
701 | struct list_head link; | |
702 | long from; | |
703 | long to; | |
704 | }; | |
705 | ||
706 | static long region_add(struct list_head *head, long f, long t) | |
707 | { | |
708 | struct file_region *rg, *nrg, *trg; | |
709 | ||
710 | /* Locate the region we are either in or before. */ | |
711 | list_for_each_entry(rg, head, link) | |
712 | if (f <= rg->to) | |
713 | break; | |
714 | ||
715 | /* Round our left edge to the current segment if it encloses us. */ | |
716 | if (f > rg->from) | |
717 | f = rg->from; | |
718 | ||
719 | /* Check for and consume any regions we now overlap with. */ | |
720 | nrg = rg; | |
721 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
722 | if (&rg->link == head) | |
723 | break; | |
724 | if (rg->from > t) | |
725 | break; | |
726 | ||
727 | /* If this area reaches higher then extend our area to | |
728 | * include it completely. If this is not the first area | |
729 | * which we intend to reuse, free it. */ | |
730 | if (rg->to > t) | |
731 | t = rg->to; | |
732 | if (rg != nrg) { | |
733 | list_del(&rg->link); | |
734 | kfree(rg); | |
735 | } | |
736 | } | |
737 | nrg->from = f; | |
738 | nrg->to = t; | |
739 | return 0; | |
740 | } | |
741 | ||
742 | static long region_chg(struct list_head *head, long f, long t) | |
743 | { | |
744 | struct file_region *rg, *nrg; | |
745 | long chg = 0; | |
746 | ||
747 | /* Locate the region we are before or in. */ | |
748 | list_for_each_entry(rg, head, link) | |
749 | if (f <= rg->to) | |
750 | break; | |
751 | ||
752 | /* If we are below the current region then a new region is required. | |
753 | * Subtle, allocate a new region at the position but make it zero | |
754 | * size such that we can guarentee to record the reservation. */ | |
755 | if (&rg->link == head || t < rg->from) { | |
756 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); | |
757 | if (nrg == 0) | |
758 | return -ENOMEM; | |
759 | nrg->from = f; | |
760 | nrg->to = f; | |
761 | INIT_LIST_HEAD(&nrg->link); | |
762 | list_add(&nrg->link, rg->link.prev); | |
763 | ||
764 | return t - f; | |
765 | } | |
766 | ||
767 | /* Round our left edge to the current segment if it encloses us. */ | |
768 | if (f > rg->from) | |
769 | f = rg->from; | |
770 | chg = t - f; | |
771 | ||
772 | /* Check for and consume any regions we now overlap with. */ | |
773 | list_for_each_entry(rg, rg->link.prev, link) { | |
774 | if (&rg->link == head) | |
775 | break; | |
776 | if (rg->from > t) | |
777 | return chg; | |
778 | ||
779 | /* We overlap with this area, if it extends futher than | |
780 | * us then we must extend ourselves. Account for its | |
781 | * existing reservation. */ | |
782 | if (rg->to > t) { | |
783 | chg += rg->to - t; | |
784 | t = rg->to; | |
785 | } | |
786 | chg -= rg->to - rg->from; | |
787 | } | |
788 | return chg; | |
789 | } | |
790 | ||
791 | static long region_truncate(struct list_head *head, long end) | |
792 | { | |
793 | struct file_region *rg, *trg; | |
794 | long chg = 0; | |
795 | ||
796 | /* Locate the region we are either in or before. */ | |
797 | list_for_each_entry(rg, head, link) | |
798 | if (end <= rg->to) | |
799 | break; | |
800 | if (&rg->link == head) | |
801 | return 0; | |
802 | ||
803 | /* If we are in the middle of a region then adjust it. */ | |
804 | if (end > rg->from) { | |
805 | chg = rg->to - end; | |
806 | rg->to = end; | |
807 | rg = list_entry(rg->link.next, typeof(*rg), link); | |
808 | } | |
809 | ||
810 | /* Drop any remaining regions. */ | |
811 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
812 | if (&rg->link == head) | |
813 | break; | |
814 | chg += rg->to - rg->from; | |
815 | list_del(&rg->link); | |
816 | kfree(rg); | |
817 | } | |
818 | return chg; | |
819 | } | |
820 | ||
821 | static int hugetlb_acct_memory(long delta) | |
822 | { | |
823 | int ret = -ENOMEM; | |
824 | ||
825 | spin_lock(&hugetlb_lock); | |
826 | if ((delta + resv_huge_pages) <= free_huge_pages) { | |
827 | resv_huge_pages += delta; | |
828 | ret = 0; | |
829 | } | |
830 | spin_unlock(&hugetlb_lock); | |
831 | return ret; | |
832 | } | |
833 | ||
834 | int hugetlb_reserve_pages(struct inode *inode, long from, long to) | |
835 | { | |
836 | long ret, chg; | |
837 | ||
838 | chg = region_chg(&inode->i_mapping->private_list, from, to); | |
839 | if (chg < 0) | |
840 | return chg; | |
8a630112 KC |
841 | /* |
842 | * When cpuset is configured, it breaks the strict hugetlb page | |
843 | * reservation as the accounting is done on a global variable. Such | |
844 | * reservation is completely rubbish in the presence of cpuset because | |
845 | * the reservation is not checked against page availability for the | |
846 | * current cpuset. Application can still potentially OOM'ed by kernel | |
847 | * with lack of free htlb page in cpuset that the task is in. | |
848 | * Attempt to enforce strict accounting with cpuset is almost | |
849 | * impossible (or too ugly) because cpuset is too fluid that | |
850 | * task or memory node can be dynamically moved between cpusets. | |
851 | * | |
852 | * The change of semantics for shared hugetlb mapping with cpuset is | |
853 | * undesirable. However, in order to preserve some of the semantics, | |
854 | * we fall back to check against current free page availability as | |
855 | * a best attempt and hopefully to minimize the impact of changing | |
856 | * semantics that cpuset has. | |
857 | */ | |
858 | if (chg > cpuset_mems_nr(free_huge_pages_node)) | |
859 | return -ENOMEM; | |
860 | ||
a43a8c39 CK |
861 | ret = hugetlb_acct_memory(chg); |
862 | if (ret < 0) | |
863 | return ret; | |
864 | region_add(&inode->i_mapping->private_list, from, to); | |
865 | return 0; | |
866 | } | |
867 | ||
868 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) | |
869 | { | |
870 | long chg = region_truncate(&inode->i_mapping->private_list, offset); | |
871 | hugetlb_acct_memory(freed - chg); | |
872 | } |