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Commit | Line | Data |
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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 DG |
13 | #include <linux/pagemap.h> |
14 | #include <asm/page.h> | |
15 | #include <asm/pgtable.h> | |
16 | ||
17 | #include <linux/hugetlb.h> | |
1da177e4 LT |
18 | |
19 | const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; | |
20 | static unsigned long nr_huge_pages, free_huge_pages; | |
21 | unsigned long max_huge_pages; | |
22 | static struct list_head hugepage_freelists[MAX_NUMNODES]; | |
23 | static unsigned int nr_huge_pages_node[MAX_NUMNODES]; | |
24 | static unsigned int free_huge_pages_node[MAX_NUMNODES]; | |
0bd0f9fb EP |
25 | |
26 | /* | |
27 | * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages | |
28 | */ | |
1da177e4 LT |
29 | static DEFINE_SPINLOCK(hugetlb_lock); |
30 | ||
31 | static void enqueue_huge_page(struct page *page) | |
32 | { | |
33 | int nid = page_to_nid(page); | |
34 | list_add(&page->lru, &hugepage_freelists[nid]); | |
35 | free_huge_pages++; | |
36 | free_huge_pages_node[nid]++; | |
37 | } | |
38 | ||
39 | static struct page *dequeue_huge_page(void) | |
40 | { | |
41 | int nid = numa_node_id(); | |
42 | struct page *page = NULL; | |
43 | ||
44 | if (list_empty(&hugepage_freelists[nid])) { | |
45 | for (nid = 0; nid < MAX_NUMNODES; ++nid) | |
46 | if (!list_empty(&hugepage_freelists[nid])) | |
47 | break; | |
48 | } | |
49 | if (nid >= 0 && nid < MAX_NUMNODES && | |
50 | !list_empty(&hugepage_freelists[nid])) { | |
51 | page = list_entry(hugepage_freelists[nid].next, | |
52 | struct page, lru); | |
53 | list_del(&page->lru); | |
54 | free_huge_pages--; | |
55 | free_huge_pages_node[nid]--; | |
56 | } | |
57 | return page; | |
58 | } | |
59 | ||
60 | static struct page *alloc_fresh_huge_page(void) | |
61 | { | |
62 | static int nid = 0; | |
63 | struct page *page; | |
64 | page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN, | |
65 | HUGETLB_PAGE_ORDER); | |
66 | nid = (nid + 1) % num_online_nodes(); | |
67 | if (page) { | |
0bd0f9fb | 68 | spin_lock(&hugetlb_lock); |
1da177e4 LT |
69 | nr_huge_pages++; |
70 | nr_huge_pages_node[page_to_nid(page)]++; | |
0bd0f9fb | 71 | spin_unlock(&hugetlb_lock); |
1da177e4 LT |
72 | } |
73 | return page; | |
74 | } | |
75 | ||
76 | void free_huge_page(struct page *page) | |
77 | { | |
78 | BUG_ON(page_count(page)); | |
79 | ||
80 | INIT_LIST_HEAD(&page->lru); | |
81 | page[1].mapping = NULL; | |
82 | ||
83 | spin_lock(&hugetlb_lock); | |
84 | enqueue_huge_page(page); | |
85 | spin_unlock(&hugetlb_lock); | |
86 | } | |
87 | ||
88 | struct page *alloc_huge_page(void) | |
89 | { | |
90 | struct page *page; | |
91 | int i; | |
92 | ||
93 | spin_lock(&hugetlb_lock); | |
94 | page = dequeue_huge_page(); | |
95 | if (!page) { | |
96 | spin_unlock(&hugetlb_lock); | |
97 | return NULL; | |
98 | } | |
99 | spin_unlock(&hugetlb_lock); | |
100 | set_page_count(page, 1); | |
101 | page[1].mapping = (void *)free_huge_page; | |
102 | for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i) | |
103 | clear_highpage(&page[i]); | |
104 | return page; | |
105 | } | |
106 | ||
107 | static int __init hugetlb_init(void) | |
108 | { | |
109 | unsigned long i; | |
110 | struct page *page; | |
111 | ||
3c726f8d BH |
112 | if (HPAGE_SHIFT == 0) |
113 | return 0; | |
114 | ||
1da177e4 LT |
115 | for (i = 0; i < MAX_NUMNODES; ++i) |
116 | INIT_LIST_HEAD(&hugepage_freelists[i]); | |
117 | ||
118 | for (i = 0; i < max_huge_pages; ++i) { | |
119 | page = alloc_fresh_huge_page(); | |
120 | if (!page) | |
121 | break; | |
122 | spin_lock(&hugetlb_lock); | |
123 | enqueue_huge_page(page); | |
124 | spin_unlock(&hugetlb_lock); | |
125 | } | |
126 | max_huge_pages = free_huge_pages = nr_huge_pages = i; | |
127 | printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); | |
128 | return 0; | |
129 | } | |
130 | module_init(hugetlb_init); | |
131 | ||
132 | static int __init hugetlb_setup(char *s) | |
133 | { | |
134 | if (sscanf(s, "%lu", &max_huge_pages) <= 0) | |
135 | max_huge_pages = 0; | |
136 | return 1; | |
137 | } | |
138 | __setup("hugepages=", hugetlb_setup); | |
139 | ||
140 | #ifdef CONFIG_SYSCTL | |
141 | static void update_and_free_page(struct page *page) | |
142 | { | |
143 | int i; | |
144 | nr_huge_pages--; | |
145 | nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--; | |
146 | for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) { | |
147 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | | |
148 | 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | | |
149 | 1 << PG_private | 1<< PG_writeback); | |
150 | set_page_count(&page[i], 0); | |
151 | } | |
152 | set_page_count(page, 1); | |
153 | __free_pages(page, HUGETLB_PAGE_ORDER); | |
154 | } | |
155 | ||
156 | #ifdef CONFIG_HIGHMEM | |
157 | static void try_to_free_low(unsigned long count) | |
158 | { | |
159 | int i, nid; | |
160 | for (i = 0; i < MAX_NUMNODES; ++i) { | |
161 | struct page *page, *next; | |
162 | list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) { | |
163 | if (PageHighMem(page)) | |
164 | continue; | |
165 | list_del(&page->lru); | |
166 | update_and_free_page(page); | |
167 | nid = page_zone(page)->zone_pgdat->node_id; | |
168 | free_huge_pages--; | |
169 | free_huge_pages_node[nid]--; | |
170 | if (count >= nr_huge_pages) | |
171 | return; | |
172 | } | |
173 | } | |
174 | } | |
175 | #else | |
176 | static inline void try_to_free_low(unsigned long count) | |
177 | { | |
178 | } | |
179 | #endif | |
180 | ||
181 | static unsigned long set_max_huge_pages(unsigned long count) | |
182 | { | |
183 | while (count > nr_huge_pages) { | |
184 | struct page *page = alloc_fresh_huge_page(); | |
185 | if (!page) | |
186 | return nr_huge_pages; | |
187 | spin_lock(&hugetlb_lock); | |
188 | enqueue_huge_page(page); | |
189 | spin_unlock(&hugetlb_lock); | |
190 | } | |
191 | if (count >= nr_huge_pages) | |
192 | return nr_huge_pages; | |
193 | ||
194 | spin_lock(&hugetlb_lock); | |
195 | try_to_free_low(count); | |
196 | while (count < nr_huge_pages) { | |
197 | struct page *page = dequeue_huge_page(); | |
198 | if (!page) | |
199 | break; | |
200 | update_and_free_page(page); | |
201 | } | |
202 | spin_unlock(&hugetlb_lock); | |
203 | return nr_huge_pages; | |
204 | } | |
205 | ||
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) | |
209 | { | |
210 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); | |
211 | max_huge_pages = set_max_huge_pages(max_huge_pages); | |
212 | return 0; | |
213 | } | |
214 | #endif /* CONFIG_SYSCTL */ | |
215 | ||
216 | int hugetlb_report_meminfo(char *buf) | |
217 | { | |
218 | return sprintf(buf, | |
219 | "HugePages_Total: %5lu\n" | |
220 | "HugePages_Free: %5lu\n" | |
221 | "Hugepagesize: %5lu kB\n", | |
222 | nr_huge_pages, | |
223 | free_huge_pages, | |
224 | HPAGE_SIZE/1024); | |
225 | } | |
226 | ||
227 | int hugetlb_report_node_meminfo(int nid, char *buf) | |
228 | { | |
229 | return sprintf(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]); | |
234 | } | |
235 | ||
236 | int is_hugepage_mem_enough(size_t size) | |
237 | { | |
238 | return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages; | |
239 | } | |
240 | ||
241 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ | |
242 | unsigned long hugetlb_total_pages(void) | |
243 | { | |
244 | return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE); | |
245 | } | |
1da177e4 LT |
246 | |
247 | /* | |
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 | |
251 | * this far. | |
252 | */ | |
253 | static struct page *hugetlb_nopage(struct vm_area_struct *vma, | |
254 | unsigned long address, int *unused) | |
255 | { | |
256 | BUG(); | |
257 | return NULL; | |
258 | } | |
259 | ||
260 | struct vm_operations_struct hugetlb_vm_ops = { | |
261 | .nopage = hugetlb_nopage, | |
262 | }; | |
263 | ||
63551ae0 DG |
264 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page) |
265 | { | |
266 | pte_t entry; | |
267 | ||
268 | if (vma->vm_flags & VM_WRITE) { | |
269 | entry = | |
270 | pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); | |
271 | } else { | |
272 | entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot)); | |
273 | } | |
274 | entry = pte_mkyoung(entry); | |
275 | entry = pte_mkhuge(entry); | |
276 | ||
277 | return entry; | |
278 | } | |
279 | ||
280 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, | |
281 | struct vm_area_struct *vma) | |
282 | { | |
283 | pte_t *src_pte, *dst_pte, entry; | |
284 | struct page *ptepage; | |
1c59827d | 285 | unsigned long addr; |
63551ae0 | 286 | |
1c59827d | 287 | for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
c74df32c HD |
288 | src_pte = huge_pte_offset(src, addr); |
289 | if (!src_pte) | |
290 | continue; | |
63551ae0 DG |
291 | dst_pte = huge_pte_alloc(dst, addr); |
292 | if (!dst_pte) | |
293 | goto nomem; | |
c74df32c | 294 | spin_lock(&dst->page_table_lock); |
1c59827d | 295 | spin_lock(&src->page_table_lock); |
c74df32c | 296 | if (!pte_none(*src_pte)) { |
1c59827d HD |
297 | entry = *src_pte; |
298 | ptepage = pte_page(entry); | |
299 | get_page(ptepage); | |
4294621f | 300 | add_mm_counter(dst, file_rss, HPAGE_SIZE / PAGE_SIZE); |
1c59827d HD |
301 | set_huge_pte_at(dst, addr, dst_pte, entry); |
302 | } | |
303 | spin_unlock(&src->page_table_lock); | |
c74df32c | 304 | spin_unlock(&dst->page_table_lock); |
63551ae0 DG |
305 | } |
306 | return 0; | |
307 | ||
308 | nomem: | |
309 | return -ENOMEM; | |
310 | } | |
311 | ||
312 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, | |
313 | unsigned long end) | |
314 | { | |
315 | struct mm_struct *mm = vma->vm_mm; | |
316 | unsigned long address; | |
c7546f8f | 317 | pte_t *ptep; |
63551ae0 DG |
318 | pte_t pte; |
319 | struct page *page; | |
320 | ||
321 | WARN_ON(!is_vm_hugetlb_page(vma)); | |
322 | BUG_ON(start & ~HPAGE_MASK); | |
323 | BUG_ON(end & ~HPAGE_MASK); | |
324 | ||
508034a3 HD |
325 | spin_lock(&mm->page_table_lock); |
326 | ||
365e9c87 HD |
327 | /* Update high watermark before we lower rss */ |
328 | update_hiwater_rss(mm); | |
329 | ||
63551ae0 | 330 | for (address = start; address < end; address += HPAGE_SIZE) { |
c7546f8f | 331 | ptep = huge_pte_offset(mm, address); |
4c887265 | 332 | if (!ptep) |
c7546f8f DG |
333 | continue; |
334 | ||
335 | pte = huge_ptep_get_and_clear(mm, address, ptep); | |
63551ae0 DG |
336 | if (pte_none(pte)) |
337 | continue; | |
c7546f8f | 338 | |
63551ae0 DG |
339 | page = pte_page(pte); |
340 | put_page(page); | |
4294621f | 341 | add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE)); |
63551ae0 | 342 | } |
63551ae0 | 343 | |
1da177e4 | 344 | spin_unlock(&mm->page_table_lock); |
508034a3 | 345 | flush_tlb_range(vma, start, end); |
1da177e4 | 346 | } |
63551ae0 | 347 | |
4c887265 AL |
348 | static struct page *find_lock_huge_page(struct address_space *mapping, |
349 | unsigned long idx) | |
63551ae0 | 350 | { |
4c887265 AL |
351 | struct page *page; |
352 | int err; | |
4c887265 AL |
353 | |
354 | retry: | |
355 | page = find_lock_page(mapping, idx); | |
356 | if (page) | |
357 | goto out; | |
358 | ||
4c887265 AL |
359 | if (hugetlb_get_quota(mapping)) |
360 | goto out; | |
361 | page = alloc_huge_page(); | |
362 | if (!page) { | |
363 | hugetlb_put_quota(mapping); | |
364 | goto out; | |
365 | } | |
63551ae0 | 366 | |
4c887265 AL |
367 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); |
368 | if (err) { | |
369 | put_page(page); | |
370 | hugetlb_put_quota(mapping); | |
371 | if (err == -EEXIST) | |
372 | goto retry; | |
373 | page = NULL; | |
63551ae0 DG |
374 | } |
375 | out: | |
4c887265 | 376 | return page; |
63551ae0 DG |
377 | } |
378 | ||
ac9b9c66 HD |
379 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
380 | unsigned long address, int write_access) | |
381 | { | |
382 | int ret = VM_FAULT_SIGBUS; | |
4c887265 AL |
383 | unsigned long idx; |
384 | unsigned long size; | |
ac9b9c66 | 385 | pte_t *pte; |
4c887265 AL |
386 | struct page *page; |
387 | struct address_space *mapping; | |
388 | ||
389 | pte = huge_pte_alloc(mm, address); | |
390 | if (!pte) | |
391 | goto out; | |
392 | ||
393 | mapping = vma->vm_file->f_mapping; | |
394 | idx = ((address - vma->vm_start) >> HPAGE_SHIFT) | |
395 | + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); | |
396 | ||
397 | /* | |
398 | * Use page lock to guard against racing truncation | |
399 | * before we get page_table_lock. | |
400 | */ | |
401 | page = find_lock_huge_page(mapping, idx); | |
402 | if (!page) | |
403 | goto out; | |
ac9b9c66 HD |
404 | |
405 | spin_lock(&mm->page_table_lock); | |
4c887265 AL |
406 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
407 | if (idx >= size) | |
408 | goto backout; | |
409 | ||
410 | ret = VM_FAULT_MINOR; | |
411 | if (!pte_none(*pte)) | |
412 | goto backout; | |
413 | ||
414 | add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE); | |
415 | set_huge_pte_at(mm, address, pte, make_huge_pte(vma, page)); | |
ac9b9c66 | 416 | spin_unlock(&mm->page_table_lock); |
4c887265 AL |
417 | unlock_page(page); |
418 | out: | |
ac9b9c66 | 419 | return ret; |
4c887265 AL |
420 | |
421 | backout: | |
422 | spin_unlock(&mm->page_table_lock); | |
423 | hugetlb_put_quota(mapping); | |
424 | unlock_page(page); | |
425 | put_page(page); | |
426 | goto out; | |
ac9b9c66 HD |
427 | } |
428 | ||
63551ae0 DG |
429 | int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
430 | struct page **pages, struct vm_area_struct **vmas, | |
431 | unsigned long *position, int *length, int i) | |
432 | { | |
433 | unsigned long vpfn, vaddr = *position; | |
434 | int remainder = *length; | |
435 | ||
63551ae0 | 436 | vpfn = vaddr/PAGE_SIZE; |
1c59827d | 437 | spin_lock(&mm->page_table_lock); |
63551ae0 | 438 | while (vaddr < vma->vm_end && remainder) { |
4c887265 AL |
439 | pte_t *pte; |
440 | struct page *page; | |
63551ae0 | 441 | |
4c887265 AL |
442 | /* |
443 | * Some archs (sparc64, sh*) have multiple pte_ts to | |
444 | * each hugepage. We have to make * sure we get the | |
445 | * first, for the page indexing below to work. | |
446 | */ | |
447 | pte = huge_pte_offset(mm, vaddr & HPAGE_MASK); | |
63551ae0 | 448 | |
4c887265 AL |
449 | if (!pte || pte_none(*pte)) { |
450 | int ret; | |
63551ae0 | 451 | |
4c887265 AL |
452 | spin_unlock(&mm->page_table_lock); |
453 | ret = hugetlb_fault(mm, vma, vaddr, 0); | |
454 | spin_lock(&mm->page_table_lock); | |
455 | if (ret == VM_FAULT_MINOR) | |
456 | continue; | |
63551ae0 | 457 | |
4c887265 AL |
458 | remainder = 0; |
459 | if (!i) | |
460 | i = -EFAULT; | |
461 | break; | |
462 | } | |
463 | ||
464 | if (pages) { | |
465 | page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)]; | |
63551ae0 DG |
466 | get_page(page); |
467 | pages[i] = page; | |
468 | } | |
469 | ||
470 | if (vmas) | |
471 | vmas[i] = vma; | |
472 | ||
473 | vaddr += PAGE_SIZE; | |
474 | ++vpfn; | |
475 | --remainder; | |
476 | ++i; | |
477 | } | |
1c59827d | 478 | spin_unlock(&mm->page_table_lock); |
63551ae0 DG |
479 | *length = remainder; |
480 | *position = vaddr; | |
481 | ||
482 | return i; | |
483 | } |