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; |
7893d1d5 | 26 | static unsigned long surplus_huge_pages; |
1da177e4 LT |
27 | unsigned long max_huge_pages; |
28 | static struct list_head hugepage_freelists[MAX_NUMNODES]; | |
29 | static unsigned int nr_huge_pages_node[MAX_NUMNODES]; | |
30 | static unsigned int free_huge_pages_node[MAX_NUMNODES]; | |
7893d1d5 | 31 | static unsigned int surplus_huge_pages_node[MAX_NUMNODES]; |
396faf03 MG |
32 | static gfp_t htlb_alloc_mask = GFP_HIGHUSER; |
33 | unsigned long hugepages_treat_as_movable; | |
34 | ||
3935baa9 DG |
35 | /* |
36 | * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages | |
37 | */ | |
38 | static DEFINE_SPINLOCK(hugetlb_lock); | |
0bd0f9fb | 39 | |
79ac6ba4 DG |
40 | static void clear_huge_page(struct page *page, unsigned long addr) |
41 | { | |
42 | int i; | |
43 | ||
44 | might_sleep(); | |
45 | for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) { | |
46 | cond_resched(); | |
281e0e3b | 47 | clear_user_highpage(page + i, addr + i * PAGE_SIZE); |
79ac6ba4 DG |
48 | } |
49 | } | |
50 | ||
51 | static void copy_huge_page(struct page *dst, struct page *src, | |
9de455b2 | 52 | unsigned long addr, struct vm_area_struct *vma) |
79ac6ba4 DG |
53 | { |
54 | int i; | |
55 | ||
56 | might_sleep(); | |
57 | for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) { | |
58 | cond_resched(); | |
9de455b2 | 59 | copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); |
79ac6ba4 DG |
60 | } |
61 | } | |
62 | ||
1da177e4 LT |
63 | static void enqueue_huge_page(struct page *page) |
64 | { | |
65 | int nid = page_to_nid(page); | |
66 | list_add(&page->lru, &hugepage_freelists[nid]); | |
67 | free_huge_pages++; | |
68 | free_huge_pages_node[nid]++; | |
69 | } | |
70 | ||
5da7ca86 CL |
71 | static struct page *dequeue_huge_page(struct vm_area_struct *vma, |
72 | unsigned long address) | |
1da177e4 | 73 | { |
31a5c6e4 | 74 | int nid; |
1da177e4 | 75 | struct page *page = NULL; |
480eccf9 | 76 | struct mempolicy *mpol; |
396faf03 | 77 | struct zonelist *zonelist = huge_zonelist(vma, address, |
480eccf9 | 78 | htlb_alloc_mask, &mpol); |
96df9333 | 79 | struct zone **z; |
1da177e4 | 80 | |
96df9333 | 81 | for (z = zonelist->zones; *z; z++) { |
89fa3024 | 82 | nid = zone_to_nid(*z); |
396faf03 | 83 | if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) && |
3abf7afd AM |
84 | !list_empty(&hugepage_freelists[nid])) { |
85 | page = list_entry(hugepage_freelists[nid].next, | |
86 | struct page, lru); | |
87 | list_del(&page->lru); | |
88 | free_huge_pages--; | |
89 | free_huge_pages_node[nid]--; | |
5ab3ee7b | 90 | break; |
3abf7afd | 91 | } |
1da177e4 | 92 | } |
480eccf9 | 93 | mpol_free(mpol); /* unref if mpol !NULL */ |
1da177e4 LT |
94 | return page; |
95 | } | |
96 | ||
6af2acb6 AL |
97 | static void update_and_free_page(struct page *page) |
98 | { | |
99 | int i; | |
100 | nr_huge_pages--; | |
101 | nr_huge_pages_node[page_to_nid(page)]--; | |
102 | for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) { | |
103 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | | |
104 | 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | | |
105 | 1 << PG_private | 1<< PG_writeback); | |
106 | } | |
107 | set_compound_page_dtor(page, NULL); | |
108 | set_page_refcounted(page); | |
109 | __free_pages(page, HUGETLB_PAGE_ORDER); | |
110 | } | |
111 | ||
27a85ef1 DG |
112 | static void free_huge_page(struct page *page) |
113 | { | |
7893d1d5 | 114 | int nid = page_to_nid(page); |
27a85ef1 | 115 | |
7893d1d5 | 116 | BUG_ON(page_count(page)); |
27a85ef1 DG |
117 | INIT_LIST_HEAD(&page->lru); |
118 | ||
119 | spin_lock(&hugetlb_lock); | |
7893d1d5 AL |
120 | if (surplus_huge_pages_node[nid]) { |
121 | update_and_free_page(page); | |
122 | surplus_huge_pages--; | |
123 | surplus_huge_pages_node[nid]--; | |
124 | } else { | |
125 | enqueue_huge_page(page); | |
126 | } | |
27a85ef1 DG |
127 | spin_unlock(&hugetlb_lock); |
128 | } | |
129 | ||
7893d1d5 AL |
130 | /* |
131 | * Increment or decrement surplus_huge_pages. Keep node-specific counters | |
132 | * balanced by operating on them in a round-robin fashion. | |
133 | * Returns 1 if an adjustment was made. | |
134 | */ | |
135 | static int adjust_pool_surplus(int delta) | |
136 | { | |
137 | static int prev_nid; | |
138 | int nid = prev_nid; | |
139 | int ret = 0; | |
140 | ||
141 | VM_BUG_ON(delta != -1 && delta != 1); | |
142 | do { | |
143 | nid = next_node(nid, node_online_map); | |
144 | if (nid == MAX_NUMNODES) | |
145 | nid = first_node(node_online_map); | |
146 | ||
147 | /* To shrink on this node, there must be a surplus page */ | |
148 | if (delta < 0 && !surplus_huge_pages_node[nid]) | |
149 | continue; | |
150 | /* Surplus cannot exceed the total number of pages */ | |
151 | if (delta > 0 && surplus_huge_pages_node[nid] >= | |
152 | nr_huge_pages_node[nid]) | |
153 | continue; | |
154 | ||
155 | surplus_huge_pages += delta; | |
156 | surplus_huge_pages_node[nid] += delta; | |
157 | ret = 1; | |
158 | break; | |
159 | } while (nid != prev_nid); | |
160 | ||
161 | prev_nid = nid; | |
162 | return ret; | |
163 | } | |
164 | ||
a482289d | 165 | static int alloc_fresh_huge_page(void) |
1da177e4 | 166 | { |
f96efd58 | 167 | static int prev_nid; |
1da177e4 | 168 | struct page *page; |
f96efd58 JJ |
169 | int nid; |
170 | ||
7ed5cb2b HD |
171 | /* |
172 | * Copy static prev_nid to local nid, work on that, then copy it | |
173 | * back to prev_nid afterwards: otherwise there's a window in which | |
174 | * a racer might pass invalid nid MAX_NUMNODES to alloc_pages_node. | |
175 | * But we don't need to use a spin_lock here: it really doesn't | |
176 | * matter if occasionally a racer chooses the same nid as we do. | |
177 | */ | |
f96efd58 | 178 | nid = next_node(prev_nid, node_online_map); |
fdb7cc59 PJ |
179 | if (nid == MAX_NUMNODES) |
180 | nid = first_node(node_online_map); | |
f96efd58 | 181 | prev_nid = nid; |
f96efd58 | 182 | |
396faf03 | 183 | page = alloc_pages_node(nid, htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN, |
f96efd58 | 184 | HUGETLB_PAGE_ORDER); |
1da177e4 | 185 | if (page) { |
33f2ef89 | 186 | set_compound_page_dtor(page, free_huge_page); |
0bd0f9fb | 187 | spin_lock(&hugetlb_lock); |
1da177e4 LT |
188 | nr_huge_pages++; |
189 | nr_huge_pages_node[page_to_nid(page)]++; | |
0bd0f9fb | 190 | spin_unlock(&hugetlb_lock); |
a482289d NP |
191 | put_page(page); /* free it into the hugepage allocator */ |
192 | return 1; | |
1da177e4 | 193 | } |
a482289d | 194 | return 0; |
1da177e4 LT |
195 | } |
196 | ||
7893d1d5 AL |
197 | static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, |
198 | unsigned long address) | |
199 | { | |
200 | struct page *page; | |
201 | ||
202 | page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN, | |
203 | HUGETLB_PAGE_ORDER); | |
204 | if (page) { | |
205 | set_compound_page_dtor(page, free_huge_page); | |
206 | spin_lock(&hugetlb_lock); | |
207 | nr_huge_pages++; | |
208 | nr_huge_pages_node[page_to_nid(page)]++; | |
209 | surplus_huge_pages++; | |
210 | surplus_huge_pages_node[page_to_nid(page)]++; | |
211 | spin_unlock(&hugetlb_lock); | |
212 | } | |
213 | ||
214 | return page; | |
215 | } | |
216 | ||
27a85ef1 DG |
217 | static struct page *alloc_huge_page(struct vm_area_struct *vma, |
218 | unsigned long addr) | |
1da177e4 | 219 | { |
7893d1d5 | 220 | struct page *page = NULL; |
1da177e4 LT |
221 | |
222 | spin_lock(&hugetlb_lock); | |
a43a8c39 CK |
223 | if (vma->vm_flags & VM_MAYSHARE) |
224 | resv_huge_pages--; | |
225 | else if (free_huge_pages <= resv_huge_pages) | |
226 | goto fail; | |
b45b5bd6 DG |
227 | |
228 | page = dequeue_huge_page(vma, addr); | |
229 | if (!page) | |
230 | goto fail; | |
231 | ||
1da177e4 | 232 | spin_unlock(&hugetlb_lock); |
7835e98b | 233 | set_page_refcounted(page); |
1da177e4 | 234 | return page; |
b45b5bd6 | 235 | |
a43a8c39 | 236 | fail: |
ace4bd29 KC |
237 | if (vma->vm_flags & VM_MAYSHARE) |
238 | resv_huge_pages++; | |
b45b5bd6 | 239 | spin_unlock(&hugetlb_lock); |
7893d1d5 AL |
240 | |
241 | /* | |
242 | * Private mappings do not use reserved huge pages so the allocation | |
243 | * may have failed due to an undersized hugetlb pool. Try to grab a | |
244 | * surplus huge page from the buddy allocator. | |
245 | */ | |
246 | if (!(vma->vm_flags & VM_MAYSHARE)) | |
247 | page = alloc_buddy_huge_page(vma, addr); | |
248 | ||
249 | return page; | |
b45b5bd6 DG |
250 | } |
251 | ||
1da177e4 LT |
252 | static int __init hugetlb_init(void) |
253 | { | |
254 | unsigned long i; | |
1da177e4 | 255 | |
3c726f8d BH |
256 | if (HPAGE_SHIFT == 0) |
257 | return 0; | |
258 | ||
1da177e4 LT |
259 | for (i = 0; i < MAX_NUMNODES; ++i) |
260 | INIT_LIST_HEAD(&hugepage_freelists[i]); | |
261 | ||
262 | for (i = 0; i < max_huge_pages; ++i) { | |
a482289d | 263 | if (!alloc_fresh_huge_page()) |
1da177e4 | 264 | break; |
1da177e4 LT |
265 | } |
266 | max_huge_pages = free_huge_pages = nr_huge_pages = i; | |
267 | printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); | |
268 | return 0; | |
269 | } | |
270 | module_init(hugetlb_init); | |
271 | ||
272 | static int __init hugetlb_setup(char *s) | |
273 | { | |
274 | if (sscanf(s, "%lu", &max_huge_pages) <= 0) | |
275 | max_huge_pages = 0; | |
276 | return 1; | |
277 | } | |
278 | __setup("hugepages=", hugetlb_setup); | |
279 | ||
8a630112 KC |
280 | static unsigned int cpuset_mems_nr(unsigned int *array) |
281 | { | |
282 | int node; | |
283 | unsigned int nr = 0; | |
284 | ||
285 | for_each_node_mask(node, cpuset_current_mems_allowed) | |
286 | nr += array[node]; | |
287 | ||
288 | return nr; | |
289 | } | |
290 | ||
1da177e4 | 291 | #ifdef CONFIG_SYSCTL |
1da177e4 LT |
292 | #ifdef CONFIG_HIGHMEM |
293 | static void try_to_free_low(unsigned long count) | |
294 | { | |
4415cc8d CL |
295 | int i; |
296 | ||
1da177e4 LT |
297 | for (i = 0; i < MAX_NUMNODES; ++i) { |
298 | struct page *page, *next; | |
299 | list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) { | |
300 | if (PageHighMem(page)) | |
301 | continue; | |
302 | list_del(&page->lru); | |
303 | update_and_free_page(page); | |
1da177e4 | 304 | free_huge_pages--; |
4415cc8d | 305 | free_huge_pages_node[page_to_nid(page)]--; |
1da177e4 LT |
306 | if (count >= nr_huge_pages) |
307 | return; | |
308 | } | |
309 | } | |
310 | } | |
311 | #else | |
312 | static inline void try_to_free_low(unsigned long count) | |
313 | { | |
314 | } | |
315 | #endif | |
316 | ||
7893d1d5 | 317 | #define persistent_huge_pages (nr_huge_pages - surplus_huge_pages) |
1da177e4 LT |
318 | static unsigned long set_max_huge_pages(unsigned long count) |
319 | { | |
7893d1d5 | 320 | unsigned long min_count, ret; |
1da177e4 | 321 | |
7893d1d5 AL |
322 | /* |
323 | * Increase the pool size | |
324 | * First take pages out of surplus state. Then make up the | |
325 | * remaining difference by allocating fresh huge pages. | |
326 | */ | |
1da177e4 | 327 | spin_lock(&hugetlb_lock); |
7893d1d5 AL |
328 | while (surplus_huge_pages && count > persistent_huge_pages) { |
329 | if (!adjust_pool_surplus(-1)) | |
330 | break; | |
331 | } | |
332 | ||
333 | while (count > persistent_huge_pages) { | |
334 | int ret; | |
335 | /* | |
336 | * If this allocation races such that we no longer need the | |
337 | * page, free_huge_page will handle it by freeing the page | |
338 | * and reducing the surplus. | |
339 | */ | |
340 | spin_unlock(&hugetlb_lock); | |
341 | ret = alloc_fresh_huge_page(); | |
342 | spin_lock(&hugetlb_lock); | |
343 | if (!ret) | |
344 | goto out; | |
345 | ||
346 | } | |
347 | if (count >= persistent_huge_pages) | |
348 | goto out; | |
349 | ||
350 | /* | |
351 | * Decrease the pool size | |
352 | * First return free pages to the buddy allocator (being careful | |
353 | * to keep enough around to satisfy reservations). Then place | |
354 | * pages into surplus state as needed so the pool will shrink | |
355 | * to the desired size as pages become free. | |
356 | */ | |
357 | min_count = max(count, resv_huge_pages); | |
358 | try_to_free_low(min_count); | |
359 | while (min_count < persistent_huge_pages) { | |
5da7ca86 | 360 | struct page *page = dequeue_huge_page(NULL, 0); |
1da177e4 LT |
361 | if (!page) |
362 | break; | |
363 | update_and_free_page(page); | |
364 | } | |
7893d1d5 AL |
365 | while (count < persistent_huge_pages) { |
366 | if (!adjust_pool_surplus(1)) | |
367 | break; | |
368 | } | |
369 | out: | |
370 | ret = persistent_huge_pages; | |
1da177e4 | 371 | spin_unlock(&hugetlb_lock); |
7893d1d5 | 372 | return ret; |
1da177e4 LT |
373 | } |
374 | ||
375 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, | |
376 | struct file *file, void __user *buffer, | |
377 | size_t *length, loff_t *ppos) | |
378 | { | |
379 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); | |
380 | max_huge_pages = set_max_huge_pages(max_huge_pages); | |
381 | return 0; | |
382 | } | |
396faf03 MG |
383 | |
384 | int hugetlb_treat_movable_handler(struct ctl_table *table, int write, | |
385 | struct file *file, void __user *buffer, | |
386 | size_t *length, loff_t *ppos) | |
387 | { | |
388 | proc_dointvec(table, write, file, buffer, length, ppos); | |
389 | if (hugepages_treat_as_movable) | |
390 | htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; | |
391 | else | |
392 | htlb_alloc_mask = GFP_HIGHUSER; | |
393 | return 0; | |
394 | } | |
395 | ||
1da177e4 LT |
396 | #endif /* CONFIG_SYSCTL */ |
397 | ||
398 | int hugetlb_report_meminfo(char *buf) | |
399 | { | |
400 | return sprintf(buf, | |
401 | "HugePages_Total: %5lu\n" | |
402 | "HugePages_Free: %5lu\n" | |
a43a8c39 | 403 | "HugePages_Rsvd: %5lu\n" |
7893d1d5 | 404 | "HugePages_Surp: %5lu\n" |
1da177e4 LT |
405 | "Hugepagesize: %5lu kB\n", |
406 | nr_huge_pages, | |
407 | free_huge_pages, | |
a43a8c39 | 408 | resv_huge_pages, |
7893d1d5 | 409 | surplus_huge_pages, |
1da177e4 LT |
410 | HPAGE_SIZE/1024); |
411 | } | |
412 | ||
413 | int hugetlb_report_node_meminfo(int nid, char *buf) | |
414 | { | |
415 | return sprintf(buf, | |
416 | "Node %d HugePages_Total: %5u\n" | |
417 | "Node %d HugePages_Free: %5u\n", | |
418 | nid, nr_huge_pages_node[nid], | |
419 | nid, free_huge_pages_node[nid]); | |
420 | } | |
421 | ||
1da177e4 LT |
422 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
423 | unsigned long hugetlb_total_pages(void) | |
424 | { | |
425 | return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE); | |
426 | } | |
1da177e4 LT |
427 | |
428 | /* | |
429 | * We cannot handle pagefaults against hugetlb pages at all. They cause | |
430 | * handle_mm_fault() to try to instantiate regular-sized pages in the | |
431 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get | |
432 | * this far. | |
433 | */ | |
d0217ac0 | 434 | static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 LT |
435 | { |
436 | BUG(); | |
d0217ac0 | 437 | return 0; |
1da177e4 LT |
438 | } |
439 | ||
440 | struct vm_operations_struct hugetlb_vm_ops = { | |
d0217ac0 | 441 | .fault = hugetlb_vm_op_fault, |
1da177e4 LT |
442 | }; |
443 | ||
1e8f889b DG |
444 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
445 | int writable) | |
63551ae0 DG |
446 | { |
447 | pte_t entry; | |
448 | ||
1e8f889b | 449 | if (writable) { |
63551ae0 DG |
450 | entry = |
451 | pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); | |
452 | } else { | |
453 | entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot)); | |
454 | } | |
455 | entry = pte_mkyoung(entry); | |
456 | entry = pte_mkhuge(entry); | |
457 | ||
458 | return entry; | |
459 | } | |
460 | ||
1e8f889b DG |
461 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
462 | unsigned long address, pte_t *ptep) | |
463 | { | |
464 | pte_t entry; | |
465 | ||
466 | entry = pte_mkwrite(pte_mkdirty(*ptep)); | |
8dab5241 BH |
467 | if (ptep_set_access_flags(vma, address, ptep, entry, 1)) { |
468 | update_mmu_cache(vma, address, entry); | |
8dab5241 | 469 | } |
1e8f889b DG |
470 | } |
471 | ||
472 | ||
63551ae0 DG |
473 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
474 | struct vm_area_struct *vma) | |
475 | { | |
476 | pte_t *src_pte, *dst_pte, entry; | |
477 | struct page *ptepage; | |
1c59827d | 478 | unsigned long addr; |
1e8f889b DG |
479 | int cow; |
480 | ||
481 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
63551ae0 | 482 | |
1c59827d | 483 | for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
c74df32c HD |
484 | src_pte = huge_pte_offset(src, addr); |
485 | if (!src_pte) | |
486 | continue; | |
63551ae0 DG |
487 | dst_pte = huge_pte_alloc(dst, addr); |
488 | if (!dst_pte) | |
489 | goto nomem; | |
c74df32c | 490 | spin_lock(&dst->page_table_lock); |
1c59827d | 491 | spin_lock(&src->page_table_lock); |
c74df32c | 492 | if (!pte_none(*src_pte)) { |
1e8f889b DG |
493 | if (cow) |
494 | ptep_set_wrprotect(src, addr, src_pte); | |
1c59827d HD |
495 | entry = *src_pte; |
496 | ptepage = pte_page(entry); | |
497 | get_page(ptepage); | |
1c59827d HD |
498 | set_huge_pte_at(dst, addr, dst_pte, entry); |
499 | } | |
500 | spin_unlock(&src->page_table_lock); | |
c74df32c | 501 | spin_unlock(&dst->page_table_lock); |
63551ae0 DG |
502 | } |
503 | return 0; | |
504 | ||
505 | nomem: | |
506 | return -ENOMEM; | |
507 | } | |
508 | ||
502717f4 CK |
509 | void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
510 | unsigned long end) | |
63551ae0 DG |
511 | { |
512 | struct mm_struct *mm = vma->vm_mm; | |
513 | unsigned long address; | |
c7546f8f | 514 | pte_t *ptep; |
63551ae0 DG |
515 | pte_t pte; |
516 | struct page *page; | |
fe1668ae | 517 | struct page *tmp; |
c0a499c2 CK |
518 | /* |
519 | * A page gathering list, protected by per file i_mmap_lock. The | |
520 | * lock is used to avoid list corruption from multiple unmapping | |
521 | * of the same page since we are using page->lru. | |
522 | */ | |
fe1668ae | 523 | LIST_HEAD(page_list); |
63551ae0 DG |
524 | |
525 | WARN_ON(!is_vm_hugetlb_page(vma)); | |
526 | BUG_ON(start & ~HPAGE_MASK); | |
527 | BUG_ON(end & ~HPAGE_MASK); | |
528 | ||
508034a3 | 529 | spin_lock(&mm->page_table_lock); |
63551ae0 | 530 | for (address = start; address < end; address += HPAGE_SIZE) { |
c7546f8f | 531 | ptep = huge_pte_offset(mm, address); |
4c887265 | 532 | if (!ptep) |
c7546f8f DG |
533 | continue; |
534 | ||
39dde65c CK |
535 | if (huge_pmd_unshare(mm, &address, ptep)) |
536 | continue; | |
537 | ||
c7546f8f | 538 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
63551ae0 DG |
539 | if (pte_none(pte)) |
540 | continue; | |
c7546f8f | 541 | |
63551ae0 | 542 | page = pte_page(pte); |
6649a386 KC |
543 | if (pte_dirty(pte)) |
544 | set_page_dirty(page); | |
fe1668ae | 545 | list_add(&page->lru, &page_list); |
63551ae0 | 546 | } |
1da177e4 | 547 | spin_unlock(&mm->page_table_lock); |
508034a3 | 548 | flush_tlb_range(vma, start, end); |
fe1668ae CK |
549 | list_for_each_entry_safe(page, tmp, &page_list, lru) { |
550 | list_del(&page->lru); | |
551 | put_page(page); | |
552 | } | |
1da177e4 | 553 | } |
63551ae0 | 554 | |
502717f4 CK |
555 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
556 | unsigned long end) | |
557 | { | |
558 | /* | |
559 | * It is undesirable to test vma->vm_file as it should be non-null | |
560 | * for valid hugetlb area. However, vm_file will be NULL in the error | |
561 | * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails, | |
562 | * do_mmap_pgoff() nullifies vma->vm_file before calling this function | |
563 | * to clean up. Since no pte has actually been setup, it is safe to | |
564 | * do nothing in this case. | |
565 | */ | |
566 | if (vma->vm_file) { | |
567 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); | |
568 | __unmap_hugepage_range(vma, start, end); | |
569 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); | |
570 | } | |
571 | } | |
572 | ||
1e8f889b DG |
573 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
574 | unsigned long address, pte_t *ptep, pte_t pte) | |
575 | { | |
576 | struct page *old_page, *new_page; | |
79ac6ba4 | 577 | int avoidcopy; |
1e8f889b DG |
578 | |
579 | old_page = pte_page(pte); | |
580 | ||
581 | /* If no-one else is actually using this page, avoid the copy | |
582 | * and just make the page writable */ | |
583 | avoidcopy = (page_count(old_page) == 1); | |
584 | if (avoidcopy) { | |
585 | set_huge_ptep_writable(vma, address, ptep); | |
83c54070 | 586 | return 0; |
1e8f889b DG |
587 | } |
588 | ||
589 | page_cache_get(old_page); | |
5da7ca86 | 590 | new_page = alloc_huge_page(vma, address); |
1e8f889b DG |
591 | |
592 | if (!new_page) { | |
593 | page_cache_release(old_page); | |
0df420d8 | 594 | return VM_FAULT_OOM; |
1e8f889b DG |
595 | } |
596 | ||
597 | spin_unlock(&mm->page_table_lock); | |
9de455b2 | 598 | copy_huge_page(new_page, old_page, address, vma); |
1e8f889b DG |
599 | spin_lock(&mm->page_table_lock); |
600 | ||
601 | ptep = huge_pte_offset(mm, address & HPAGE_MASK); | |
602 | if (likely(pte_same(*ptep, pte))) { | |
603 | /* Break COW */ | |
604 | set_huge_pte_at(mm, address, ptep, | |
605 | make_huge_pte(vma, new_page, 1)); | |
606 | /* Make the old page be freed below */ | |
607 | new_page = old_page; | |
608 | } | |
609 | page_cache_release(new_page); | |
610 | page_cache_release(old_page); | |
83c54070 | 611 | return 0; |
1e8f889b DG |
612 | } |
613 | ||
a1ed3dda | 614 | static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1e8f889b | 615 | unsigned long address, pte_t *ptep, int write_access) |
ac9b9c66 HD |
616 | { |
617 | int ret = VM_FAULT_SIGBUS; | |
4c887265 AL |
618 | unsigned long idx; |
619 | unsigned long size; | |
4c887265 AL |
620 | struct page *page; |
621 | struct address_space *mapping; | |
1e8f889b | 622 | pte_t new_pte; |
4c887265 | 623 | |
4c887265 AL |
624 | mapping = vma->vm_file->f_mapping; |
625 | idx = ((address - vma->vm_start) >> HPAGE_SHIFT) | |
626 | + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); | |
627 | ||
628 | /* | |
629 | * Use page lock to guard against racing truncation | |
630 | * before we get page_table_lock. | |
631 | */ | |
6bda666a CL |
632 | retry: |
633 | page = find_lock_page(mapping, idx); | |
634 | if (!page) { | |
ebed4bfc HD |
635 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
636 | if (idx >= size) | |
637 | goto out; | |
6bda666a CL |
638 | if (hugetlb_get_quota(mapping)) |
639 | goto out; | |
640 | page = alloc_huge_page(vma, address); | |
641 | if (!page) { | |
642 | hugetlb_put_quota(mapping); | |
0df420d8 | 643 | ret = VM_FAULT_OOM; |
6bda666a CL |
644 | goto out; |
645 | } | |
79ac6ba4 | 646 | clear_huge_page(page, address); |
ac9b9c66 | 647 | |
6bda666a CL |
648 | if (vma->vm_flags & VM_SHARED) { |
649 | int err; | |
650 | ||
651 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); | |
652 | if (err) { | |
653 | put_page(page); | |
654 | hugetlb_put_quota(mapping); | |
655 | if (err == -EEXIST) | |
656 | goto retry; | |
657 | goto out; | |
658 | } | |
659 | } else | |
660 | lock_page(page); | |
661 | } | |
1e8f889b | 662 | |
ac9b9c66 | 663 | spin_lock(&mm->page_table_lock); |
4c887265 AL |
664 | size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
665 | if (idx >= size) | |
666 | goto backout; | |
667 | ||
83c54070 | 668 | ret = 0; |
86e5216f | 669 | if (!pte_none(*ptep)) |
4c887265 AL |
670 | goto backout; |
671 | ||
1e8f889b DG |
672 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
673 | && (vma->vm_flags & VM_SHARED))); | |
674 | set_huge_pte_at(mm, address, ptep, new_pte); | |
675 | ||
676 | if (write_access && !(vma->vm_flags & VM_SHARED)) { | |
677 | /* Optimization, do the COW without a second fault */ | |
678 | ret = hugetlb_cow(mm, vma, address, ptep, new_pte); | |
679 | } | |
680 | ||
ac9b9c66 | 681 | spin_unlock(&mm->page_table_lock); |
4c887265 AL |
682 | unlock_page(page); |
683 | out: | |
ac9b9c66 | 684 | return ret; |
4c887265 AL |
685 | |
686 | backout: | |
687 | spin_unlock(&mm->page_table_lock); | |
688 | hugetlb_put_quota(mapping); | |
689 | unlock_page(page); | |
690 | put_page(page); | |
691 | goto out; | |
ac9b9c66 HD |
692 | } |
693 | ||
86e5216f AL |
694 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
695 | unsigned long address, int write_access) | |
696 | { | |
697 | pte_t *ptep; | |
698 | pte_t entry; | |
1e8f889b | 699 | int ret; |
3935baa9 | 700 | static DEFINE_MUTEX(hugetlb_instantiation_mutex); |
86e5216f AL |
701 | |
702 | ptep = huge_pte_alloc(mm, address); | |
703 | if (!ptep) | |
704 | return VM_FAULT_OOM; | |
705 | ||
3935baa9 DG |
706 | /* |
707 | * Serialize hugepage allocation and instantiation, so that we don't | |
708 | * get spurious allocation failures if two CPUs race to instantiate | |
709 | * the same page in the page cache. | |
710 | */ | |
711 | mutex_lock(&hugetlb_instantiation_mutex); | |
86e5216f | 712 | entry = *ptep; |
3935baa9 DG |
713 | if (pte_none(entry)) { |
714 | ret = hugetlb_no_page(mm, vma, address, ptep, write_access); | |
715 | mutex_unlock(&hugetlb_instantiation_mutex); | |
716 | return ret; | |
717 | } | |
86e5216f | 718 | |
83c54070 | 719 | ret = 0; |
1e8f889b DG |
720 | |
721 | spin_lock(&mm->page_table_lock); | |
722 | /* Check for a racing update before calling hugetlb_cow */ | |
723 | if (likely(pte_same(entry, *ptep))) | |
724 | if (write_access && !pte_write(entry)) | |
725 | ret = hugetlb_cow(mm, vma, address, ptep, entry); | |
726 | spin_unlock(&mm->page_table_lock); | |
3935baa9 | 727 | mutex_unlock(&hugetlb_instantiation_mutex); |
1e8f889b DG |
728 | |
729 | return ret; | |
86e5216f AL |
730 | } |
731 | ||
63551ae0 DG |
732 | int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
733 | struct page **pages, struct vm_area_struct **vmas, | |
734 | unsigned long *position, int *length, int i) | |
735 | { | |
d5d4b0aa CK |
736 | unsigned long pfn_offset; |
737 | unsigned long vaddr = *position; | |
63551ae0 DG |
738 | int remainder = *length; |
739 | ||
1c59827d | 740 | spin_lock(&mm->page_table_lock); |
63551ae0 | 741 | while (vaddr < vma->vm_end && remainder) { |
4c887265 AL |
742 | pte_t *pte; |
743 | struct page *page; | |
63551ae0 | 744 | |
4c887265 AL |
745 | /* |
746 | * Some archs (sparc64, sh*) have multiple pte_ts to | |
747 | * each hugepage. We have to make * sure we get the | |
748 | * first, for the page indexing below to work. | |
749 | */ | |
750 | pte = huge_pte_offset(mm, vaddr & HPAGE_MASK); | |
63551ae0 | 751 | |
4c887265 AL |
752 | if (!pte || pte_none(*pte)) { |
753 | int ret; | |
63551ae0 | 754 | |
4c887265 AL |
755 | spin_unlock(&mm->page_table_lock); |
756 | ret = hugetlb_fault(mm, vma, vaddr, 0); | |
757 | spin_lock(&mm->page_table_lock); | |
a89182c7 | 758 | if (!(ret & VM_FAULT_ERROR)) |
4c887265 | 759 | continue; |
63551ae0 | 760 | |
4c887265 AL |
761 | remainder = 0; |
762 | if (!i) | |
763 | i = -EFAULT; | |
764 | break; | |
765 | } | |
766 | ||
d5d4b0aa CK |
767 | pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT; |
768 | page = pte_page(*pte); | |
769 | same_page: | |
d6692183 CK |
770 | if (pages) { |
771 | get_page(page); | |
d5d4b0aa | 772 | pages[i] = page + pfn_offset; |
d6692183 | 773 | } |
63551ae0 DG |
774 | |
775 | if (vmas) | |
776 | vmas[i] = vma; | |
777 | ||
778 | vaddr += PAGE_SIZE; | |
d5d4b0aa | 779 | ++pfn_offset; |
63551ae0 DG |
780 | --remainder; |
781 | ++i; | |
d5d4b0aa CK |
782 | if (vaddr < vma->vm_end && remainder && |
783 | pfn_offset < HPAGE_SIZE/PAGE_SIZE) { | |
784 | /* | |
785 | * We use pfn_offset to avoid touching the pageframes | |
786 | * of this compound page. | |
787 | */ | |
788 | goto same_page; | |
789 | } | |
63551ae0 | 790 | } |
1c59827d | 791 | spin_unlock(&mm->page_table_lock); |
63551ae0 DG |
792 | *length = remainder; |
793 | *position = vaddr; | |
794 | ||
795 | return i; | |
796 | } | |
8f860591 ZY |
797 | |
798 | void hugetlb_change_protection(struct vm_area_struct *vma, | |
799 | unsigned long address, unsigned long end, pgprot_t newprot) | |
800 | { | |
801 | struct mm_struct *mm = vma->vm_mm; | |
802 | unsigned long start = address; | |
803 | pte_t *ptep; | |
804 | pte_t pte; | |
805 | ||
806 | BUG_ON(address >= end); | |
807 | flush_cache_range(vma, address, end); | |
808 | ||
39dde65c | 809 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
810 | spin_lock(&mm->page_table_lock); |
811 | for (; address < end; address += HPAGE_SIZE) { | |
812 | ptep = huge_pte_offset(mm, address); | |
813 | if (!ptep) | |
814 | continue; | |
39dde65c CK |
815 | if (huge_pmd_unshare(mm, &address, ptep)) |
816 | continue; | |
8f860591 ZY |
817 | if (!pte_none(*ptep)) { |
818 | pte = huge_ptep_get_and_clear(mm, address, ptep); | |
819 | pte = pte_mkhuge(pte_modify(pte, newprot)); | |
820 | set_huge_pte_at(mm, address, ptep, pte); | |
8f860591 ZY |
821 | } |
822 | } | |
823 | spin_unlock(&mm->page_table_lock); | |
39dde65c | 824 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
8f860591 ZY |
825 | |
826 | flush_tlb_range(vma, start, end); | |
827 | } | |
828 | ||
a43a8c39 CK |
829 | struct file_region { |
830 | struct list_head link; | |
831 | long from; | |
832 | long to; | |
833 | }; | |
834 | ||
835 | static long region_add(struct list_head *head, long f, long t) | |
836 | { | |
837 | struct file_region *rg, *nrg, *trg; | |
838 | ||
839 | /* Locate the region we are either in or before. */ | |
840 | list_for_each_entry(rg, head, link) | |
841 | if (f <= rg->to) | |
842 | break; | |
843 | ||
844 | /* Round our left edge to the current segment if it encloses us. */ | |
845 | if (f > rg->from) | |
846 | f = rg->from; | |
847 | ||
848 | /* Check for and consume any regions we now overlap with. */ | |
849 | nrg = rg; | |
850 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
851 | if (&rg->link == head) | |
852 | break; | |
853 | if (rg->from > t) | |
854 | break; | |
855 | ||
856 | /* If this area reaches higher then extend our area to | |
857 | * include it completely. If this is not the first area | |
858 | * which we intend to reuse, free it. */ | |
859 | if (rg->to > t) | |
860 | t = rg->to; | |
861 | if (rg != nrg) { | |
862 | list_del(&rg->link); | |
863 | kfree(rg); | |
864 | } | |
865 | } | |
866 | nrg->from = f; | |
867 | nrg->to = t; | |
868 | return 0; | |
869 | } | |
870 | ||
871 | static long region_chg(struct list_head *head, long f, long t) | |
872 | { | |
873 | struct file_region *rg, *nrg; | |
874 | long chg = 0; | |
875 | ||
876 | /* Locate the region we are before or in. */ | |
877 | list_for_each_entry(rg, head, link) | |
878 | if (f <= rg->to) | |
879 | break; | |
880 | ||
881 | /* If we are below the current region then a new region is required. | |
882 | * Subtle, allocate a new region at the position but make it zero | |
883 | * size such that we can guarentee to record the reservation. */ | |
884 | if (&rg->link == head || t < rg->from) { | |
885 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); | |
886 | if (nrg == 0) | |
887 | return -ENOMEM; | |
888 | nrg->from = f; | |
889 | nrg->to = f; | |
890 | INIT_LIST_HEAD(&nrg->link); | |
891 | list_add(&nrg->link, rg->link.prev); | |
892 | ||
893 | return t - f; | |
894 | } | |
895 | ||
896 | /* Round our left edge to the current segment if it encloses us. */ | |
897 | if (f > rg->from) | |
898 | f = rg->from; | |
899 | chg = t - f; | |
900 | ||
901 | /* Check for and consume any regions we now overlap with. */ | |
902 | list_for_each_entry(rg, rg->link.prev, link) { | |
903 | if (&rg->link == head) | |
904 | break; | |
905 | if (rg->from > t) | |
906 | return chg; | |
907 | ||
908 | /* We overlap with this area, if it extends futher than | |
909 | * us then we must extend ourselves. Account for its | |
910 | * existing reservation. */ | |
911 | if (rg->to > t) { | |
912 | chg += rg->to - t; | |
913 | t = rg->to; | |
914 | } | |
915 | chg -= rg->to - rg->from; | |
916 | } | |
917 | return chg; | |
918 | } | |
919 | ||
920 | static long region_truncate(struct list_head *head, long end) | |
921 | { | |
922 | struct file_region *rg, *trg; | |
923 | long chg = 0; | |
924 | ||
925 | /* Locate the region we are either in or before. */ | |
926 | list_for_each_entry(rg, head, link) | |
927 | if (end <= rg->to) | |
928 | break; | |
929 | if (&rg->link == head) | |
930 | return 0; | |
931 | ||
932 | /* If we are in the middle of a region then adjust it. */ | |
933 | if (end > rg->from) { | |
934 | chg = rg->to - end; | |
935 | rg->to = end; | |
936 | rg = list_entry(rg->link.next, typeof(*rg), link); | |
937 | } | |
938 | ||
939 | /* Drop any remaining regions. */ | |
940 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { | |
941 | if (&rg->link == head) | |
942 | break; | |
943 | chg += rg->to - rg->from; | |
944 | list_del(&rg->link); | |
945 | kfree(rg); | |
946 | } | |
947 | return chg; | |
948 | } | |
949 | ||
950 | static int hugetlb_acct_memory(long delta) | |
951 | { | |
952 | int ret = -ENOMEM; | |
953 | ||
954 | spin_lock(&hugetlb_lock); | |
955 | if ((delta + resv_huge_pages) <= free_huge_pages) { | |
956 | resv_huge_pages += delta; | |
957 | ret = 0; | |
958 | } | |
959 | spin_unlock(&hugetlb_lock); | |
960 | return ret; | |
961 | } | |
962 | ||
963 | int hugetlb_reserve_pages(struct inode *inode, long from, long to) | |
964 | { | |
965 | long ret, chg; | |
966 | ||
967 | chg = region_chg(&inode->i_mapping->private_list, from, to); | |
968 | if (chg < 0) | |
969 | return chg; | |
8a630112 KC |
970 | /* |
971 | * When cpuset is configured, it breaks the strict hugetlb page | |
972 | * reservation as the accounting is done on a global variable. Such | |
973 | * reservation is completely rubbish in the presence of cpuset because | |
974 | * the reservation is not checked against page availability for the | |
975 | * current cpuset. Application can still potentially OOM'ed by kernel | |
976 | * with lack of free htlb page in cpuset that the task is in. | |
977 | * Attempt to enforce strict accounting with cpuset is almost | |
978 | * impossible (or too ugly) because cpuset is too fluid that | |
979 | * task or memory node can be dynamically moved between cpusets. | |
980 | * | |
981 | * The change of semantics for shared hugetlb mapping with cpuset is | |
982 | * undesirable. However, in order to preserve some of the semantics, | |
983 | * we fall back to check against current free page availability as | |
984 | * a best attempt and hopefully to minimize the impact of changing | |
985 | * semantics that cpuset has. | |
986 | */ | |
987 | if (chg > cpuset_mems_nr(free_huge_pages_node)) | |
988 | return -ENOMEM; | |
989 | ||
a43a8c39 CK |
990 | ret = hugetlb_acct_memory(chg); |
991 | if (ret < 0) | |
992 | return ret; | |
993 | region_add(&inode->i_mapping->private_list, from, to); | |
994 | return 0; | |
995 | } | |
996 | ||
997 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) | |
998 | { | |
999 | long chg = region_truncate(&inode->i_mapping->private_list, offset); | |
1000 | hugetlb_acct_memory(freed - chg); | |
1001 | } |