Commit | Line | Data |
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71e3aac0 AA |
1 | /* |
2 | * Copyright (C) 2009 Red Hat, Inc. | |
3 | * | |
4 | * This work is licensed under the terms of the GNU GPL, version 2. See | |
5 | * the COPYING file in the top-level directory. | |
6 | */ | |
7 | ||
8 | #include <linux/mm.h> | |
9 | #include <linux/sched.h> | |
10 | #include <linux/highmem.h> | |
11 | #include <linux/hugetlb.h> | |
12 | #include <linux/mmu_notifier.h> | |
13 | #include <linux/rmap.h> | |
14 | #include <linux/swap.h> | |
ba76149f AA |
15 | #include <linux/mm_inline.h> |
16 | #include <linux/kthread.h> | |
17 | #include <linux/khugepaged.h> | |
878aee7d | 18 | #include <linux/freezer.h> |
a664b2d8 | 19 | #include <linux/mman.h> |
325adeb5 | 20 | #include <linux/pagemap.h> |
71e3aac0 AA |
21 | #include <asm/tlb.h> |
22 | #include <asm/pgalloc.h> | |
23 | #include "internal.h" | |
24 | ||
ba76149f AA |
25 | /* |
26 | * By default transparent hugepage support is enabled for all mappings | |
27 | * and khugepaged scans all mappings. Defrag is only invoked by | |
28 | * khugepaged hugepage allocations and by page faults inside | |
29 | * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived | |
30 | * allocations. | |
31 | */ | |
71e3aac0 | 32 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 33 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 34 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
35 | #endif |
36 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
37 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
38 | #endif | |
d39d33c3 | 39 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| |
ba76149f AA |
40 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); |
41 | ||
42 | /* default scan 8*512 pte (or vmas) every 30 second */ | |
43 | static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; | |
44 | static unsigned int khugepaged_pages_collapsed; | |
45 | static unsigned int khugepaged_full_scans; | |
46 | static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; | |
47 | /* during fragmentation poll the hugepage allocator once every minute */ | |
48 | static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; | |
49 | static struct task_struct *khugepaged_thread __read_mostly; | |
4a6c1297 | 50 | static unsigned long huge_zero_pfn __read_mostly; |
ba76149f AA |
51 | static DEFINE_MUTEX(khugepaged_mutex); |
52 | static DEFINE_SPINLOCK(khugepaged_mm_lock); | |
53 | static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait); | |
54 | /* | |
55 | * default collapse hugepages if there is at least one pte mapped like | |
56 | * it would have happened if the vma was large enough during page | |
57 | * fault. | |
58 | */ | |
59 | static unsigned int khugepaged_max_ptes_none __read_mostly = HPAGE_PMD_NR-1; | |
60 | ||
61 | static int khugepaged(void *none); | |
62 | static int mm_slots_hash_init(void); | |
63 | static int khugepaged_slab_init(void); | |
64 | static void khugepaged_slab_free(void); | |
65 | ||
66 | #define MM_SLOTS_HASH_HEADS 1024 | |
67 | static struct hlist_head *mm_slots_hash __read_mostly; | |
68 | static struct kmem_cache *mm_slot_cache __read_mostly; | |
69 | ||
70 | /** | |
71 | * struct mm_slot - hash lookup from mm to mm_slot | |
72 | * @hash: hash collision list | |
73 | * @mm_node: khugepaged scan list headed in khugepaged_scan.mm_head | |
74 | * @mm: the mm that this information is valid for | |
75 | */ | |
76 | struct mm_slot { | |
77 | struct hlist_node hash; | |
78 | struct list_head mm_node; | |
79 | struct mm_struct *mm; | |
80 | }; | |
81 | ||
82 | /** | |
83 | * struct khugepaged_scan - cursor for scanning | |
84 | * @mm_head: the head of the mm list to scan | |
85 | * @mm_slot: the current mm_slot we are scanning | |
86 | * @address: the next address inside that to be scanned | |
87 | * | |
88 | * There is only the one khugepaged_scan instance of this cursor structure. | |
89 | */ | |
90 | struct khugepaged_scan { | |
91 | struct list_head mm_head; | |
92 | struct mm_slot *mm_slot; | |
93 | unsigned long address; | |
2f1da642 HS |
94 | }; |
95 | static struct khugepaged_scan khugepaged_scan = { | |
ba76149f AA |
96 | .mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head), |
97 | }; | |
98 | ||
f000565a AA |
99 | |
100 | static int set_recommended_min_free_kbytes(void) | |
101 | { | |
102 | struct zone *zone; | |
103 | int nr_zones = 0; | |
104 | unsigned long recommended_min; | |
105 | extern int min_free_kbytes; | |
106 | ||
17c230af | 107 | if (!khugepaged_enabled()) |
f000565a AA |
108 | return 0; |
109 | ||
110 | for_each_populated_zone(zone) | |
111 | nr_zones++; | |
112 | ||
113 | /* Make sure at least 2 hugepages are free for MIGRATE_RESERVE */ | |
114 | recommended_min = pageblock_nr_pages * nr_zones * 2; | |
115 | ||
116 | /* | |
117 | * Make sure that on average at least two pageblocks are almost free | |
118 | * of another type, one for a migratetype to fall back to and a | |
119 | * second to avoid subsequent fallbacks of other types There are 3 | |
120 | * MIGRATE_TYPES we care about. | |
121 | */ | |
122 | recommended_min += pageblock_nr_pages * nr_zones * | |
123 | MIGRATE_PCPTYPES * MIGRATE_PCPTYPES; | |
124 | ||
125 | /* don't ever allow to reserve more than 5% of the lowmem */ | |
126 | recommended_min = min(recommended_min, | |
127 | (unsigned long) nr_free_buffer_pages() / 20); | |
128 | recommended_min <<= (PAGE_SHIFT-10); | |
129 | ||
130 | if (recommended_min > min_free_kbytes) | |
131 | min_free_kbytes = recommended_min; | |
132 | setup_per_zone_wmarks(); | |
133 | return 0; | |
134 | } | |
135 | late_initcall(set_recommended_min_free_kbytes); | |
136 | ||
ba76149f AA |
137 | static int start_khugepaged(void) |
138 | { | |
139 | int err = 0; | |
140 | if (khugepaged_enabled()) { | |
ba76149f AA |
141 | if (!khugepaged_thread) |
142 | khugepaged_thread = kthread_run(khugepaged, NULL, | |
143 | "khugepaged"); | |
144 | if (unlikely(IS_ERR(khugepaged_thread))) { | |
145 | printk(KERN_ERR | |
146 | "khugepaged: kthread_run(khugepaged) failed\n"); | |
147 | err = PTR_ERR(khugepaged_thread); | |
148 | khugepaged_thread = NULL; | |
149 | } | |
911891af XG |
150 | |
151 | if (!list_empty(&khugepaged_scan.mm_head)) | |
ba76149f | 152 | wake_up_interruptible(&khugepaged_wait); |
f000565a AA |
153 | |
154 | set_recommended_min_free_kbytes(); | |
911891af | 155 | } else if (khugepaged_thread) { |
911891af XG |
156 | kthread_stop(khugepaged_thread); |
157 | khugepaged_thread = NULL; | |
158 | } | |
637e3a27 | 159 | |
ba76149f AA |
160 | return err; |
161 | } | |
71e3aac0 | 162 | |
4a6c1297 KS |
163 | static int __init init_huge_zero_page(void) |
164 | { | |
165 | struct page *hpage; | |
166 | ||
167 | hpage = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE, | |
168 | HPAGE_PMD_ORDER); | |
169 | if (!hpage) | |
170 | return -ENOMEM; | |
171 | ||
172 | huge_zero_pfn = page_to_pfn(hpage); | |
173 | return 0; | |
174 | } | |
175 | ||
176 | static inline bool is_huge_zero_pfn(unsigned long pfn) | |
177 | { | |
178 | return pfn == huge_zero_pfn; | |
179 | } | |
180 | ||
181 | static inline bool is_huge_zero_pmd(pmd_t pmd) | |
182 | { | |
183 | return is_huge_zero_pfn(pmd_pfn(pmd)); | |
184 | } | |
185 | ||
71e3aac0 | 186 | #ifdef CONFIG_SYSFS |
ba76149f | 187 | |
71e3aac0 AA |
188 | static ssize_t double_flag_show(struct kobject *kobj, |
189 | struct kobj_attribute *attr, char *buf, | |
190 | enum transparent_hugepage_flag enabled, | |
191 | enum transparent_hugepage_flag req_madv) | |
192 | { | |
193 | if (test_bit(enabled, &transparent_hugepage_flags)) { | |
194 | VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); | |
195 | return sprintf(buf, "[always] madvise never\n"); | |
196 | } else if (test_bit(req_madv, &transparent_hugepage_flags)) | |
197 | return sprintf(buf, "always [madvise] never\n"); | |
198 | else | |
199 | return sprintf(buf, "always madvise [never]\n"); | |
200 | } | |
201 | static ssize_t double_flag_store(struct kobject *kobj, | |
202 | struct kobj_attribute *attr, | |
203 | const char *buf, size_t count, | |
204 | enum transparent_hugepage_flag enabled, | |
205 | enum transparent_hugepage_flag req_madv) | |
206 | { | |
207 | if (!memcmp("always", buf, | |
208 | min(sizeof("always")-1, count))) { | |
209 | set_bit(enabled, &transparent_hugepage_flags); | |
210 | clear_bit(req_madv, &transparent_hugepage_flags); | |
211 | } else if (!memcmp("madvise", buf, | |
212 | min(sizeof("madvise")-1, count))) { | |
213 | clear_bit(enabled, &transparent_hugepage_flags); | |
214 | set_bit(req_madv, &transparent_hugepage_flags); | |
215 | } else if (!memcmp("never", buf, | |
216 | min(sizeof("never")-1, count))) { | |
217 | clear_bit(enabled, &transparent_hugepage_flags); | |
218 | clear_bit(req_madv, &transparent_hugepage_flags); | |
219 | } else | |
220 | return -EINVAL; | |
221 | ||
222 | return count; | |
223 | } | |
224 | ||
225 | static ssize_t enabled_show(struct kobject *kobj, | |
226 | struct kobj_attribute *attr, char *buf) | |
227 | { | |
228 | return double_flag_show(kobj, attr, buf, | |
229 | TRANSPARENT_HUGEPAGE_FLAG, | |
230 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
231 | } | |
232 | static ssize_t enabled_store(struct kobject *kobj, | |
233 | struct kobj_attribute *attr, | |
234 | const char *buf, size_t count) | |
235 | { | |
ba76149f AA |
236 | ssize_t ret; |
237 | ||
238 | ret = double_flag_store(kobj, attr, buf, count, | |
239 | TRANSPARENT_HUGEPAGE_FLAG, | |
240 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
241 | ||
242 | if (ret > 0) { | |
911891af XG |
243 | int err; |
244 | ||
245 | mutex_lock(&khugepaged_mutex); | |
246 | err = start_khugepaged(); | |
247 | mutex_unlock(&khugepaged_mutex); | |
248 | ||
ba76149f AA |
249 | if (err) |
250 | ret = err; | |
251 | } | |
252 | ||
253 | return ret; | |
71e3aac0 AA |
254 | } |
255 | static struct kobj_attribute enabled_attr = | |
256 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
257 | ||
258 | static ssize_t single_flag_show(struct kobject *kobj, | |
259 | struct kobj_attribute *attr, char *buf, | |
260 | enum transparent_hugepage_flag flag) | |
261 | { | |
e27e6151 BH |
262 | return sprintf(buf, "%d\n", |
263 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 264 | } |
e27e6151 | 265 | |
71e3aac0 AA |
266 | static ssize_t single_flag_store(struct kobject *kobj, |
267 | struct kobj_attribute *attr, | |
268 | const char *buf, size_t count, | |
269 | enum transparent_hugepage_flag flag) | |
270 | { | |
e27e6151 BH |
271 | unsigned long value; |
272 | int ret; | |
273 | ||
274 | ret = kstrtoul(buf, 10, &value); | |
275 | if (ret < 0) | |
276 | return ret; | |
277 | if (value > 1) | |
278 | return -EINVAL; | |
279 | ||
280 | if (value) | |
71e3aac0 | 281 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 282 | else |
71e3aac0 | 283 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
284 | |
285 | return count; | |
286 | } | |
287 | ||
288 | /* | |
289 | * Currently defrag only disables __GFP_NOWAIT for allocation. A blind | |
290 | * __GFP_REPEAT is too aggressive, it's never worth swapping tons of | |
291 | * memory just to allocate one more hugepage. | |
292 | */ | |
293 | static ssize_t defrag_show(struct kobject *kobj, | |
294 | struct kobj_attribute *attr, char *buf) | |
295 | { | |
296 | return double_flag_show(kobj, attr, buf, | |
297 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
298 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
299 | } | |
300 | static ssize_t defrag_store(struct kobject *kobj, | |
301 | struct kobj_attribute *attr, | |
302 | const char *buf, size_t count) | |
303 | { | |
304 | return double_flag_store(kobj, attr, buf, count, | |
305 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
306 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
307 | } | |
308 | static struct kobj_attribute defrag_attr = | |
309 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
310 | ||
311 | #ifdef CONFIG_DEBUG_VM | |
312 | static ssize_t debug_cow_show(struct kobject *kobj, | |
313 | struct kobj_attribute *attr, char *buf) | |
314 | { | |
315 | return single_flag_show(kobj, attr, buf, | |
316 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
317 | } | |
318 | static ssize_t debug_cow_store(struct kobject *kobj, | |
319 | struct kobj_attribute *attr, | |
320 | const char *buf, size_t count) | |
321 | { | |
322 | return single_flag_store(kobj, attr, buf, count, | |
323 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
324 | } | |
325 | static struct kobj_attribute debug_cow_attr = | |
326 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
327 | #endif /* CONFIG_DEBUG_VM */ | |
328 | ||
329 | static struct attribute *hugepage_attr[] = { | |
330 | &enabled_attr.attr, | |
331 | &defrag_attr.attr, | |
332 | #ifdef CONFIG_DEBUG_VM | |
333 | &debug_cow_attr.attr, | |
334 | #endif | |
335 | NULL, | |
336 | }; | |
337 | ||
338 | static struct attribute_group hugepage_attr_group = { | |
339 | .attrs = hugepage_attr, | |
ba76149f AA |
340 | }; |
341 | ||
342 | static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, | |
343 | struct kobj_attribute *attr, | |
344 | char *buf) | |
345 | { | |
346 | return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); | |
347 | } | |
348 | ||
349 | static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, | |
350 | struct kobj_attribute *attr, | |
351 | const char *buf, size_t count) | |
352 | { | |
353 | unsigned long msecs; | |
354 | int err; | |
355 | ||
356 | err = strict_strtoul(buf, 10, &msecs); | |
357 | if (err || msecs > UINT_MAX) | |
358 | return -EINVAL; | |
359 | ||
360 | khugepaged_scan_sleep_millisecs = msecs; | |
361 | wake_up_interruptible(&khugepaged_wait); | |
362 | ||
363 | return count; | |
364 | } | |
365 | static struct kobj_attribute scan_sleep_millisecs_attr = | |
366 | __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, | |
367 | scan_sleep_millisecs_store); | |
368 | ||
369 | static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, | |
370 | struct kobj_attribute *attr, | |
371 | char *buf) | |
372 | { | |
373 | return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); | |
374 | } | |
375 | ||
376 | static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, | |
377 | struct kobj_attribute *attr, | |
378 | const char *buf, size_t count) | |
379 | { | |
380 | unsigned long msecs; | |
381 | int err; | |
382 | ||
383 | err = strict_strtoul(buf, 10, &msecs); | |
384 | if (err || msecs > UINT_MAX) | |
385 | return -EINVAL; | |
386 | ||
387 | khugepaged_alloc_sleep_millisecs = msecs; | |
388 | wake_up_interruptible(&khugepaged_wait); | |
389 | ||
390 | return count; | |
391 | } | |
392 | static struct kobj_attribute alloc_sleep_millisecs_attr = | |
393 | __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, | |
394 | alloc_sleep_millisecs_store); | |
395 | ||
396 | static ssize_t pages_to_scan_show(struct kobject *kobj, | |
397 | struct kobj_attribute *attr, | |
398 | char *buf) | |
399 | { | |
400 | return sprintf(buf, "%u\n", khugepaged_pages_to_scan); | |
401 | } | |
402 | static ssize_t pages_to_scan_store(struct kobject *kobj, | |
403 | struct kobj_attribute *attr, | |
404 | const char *buf, size_t count) | |
405 | { | |
406 | int err; | |
407 | unsigned long pages; | |
408 | ||
409 | err = strict_strtoul(buf, 10, &pages); | |
410 | if (err || !pages || pages > UINT_MAX) | |
411 | return -EINVAL; | |
412 | ||
413 | khugepaged_pages_to_scan = pages; | |
414 | ||
415 | return count; | |
416 | } | |
417 | static struct kobj_attribute pages_to_scan_attr = | |
418 | __ATTR(pages_to_scan, 0644, pages_to_scan_show, | |
419 | pages_to_scan_store); | |
420 | ||
421 | static ssize_t pages_collapsed_show(struct kobject *kobj, | |
422 | struct kobj_attribute *attr, | |
423 | char *buf) | |
424 | { | |
425 | return sprintf(buf, "%u\n", khugepaged_pages_collapsed); | |
426 | } | |
427 | static struct kobj_attribute pages_collapsed_attr = | |
428 | __ATTR_RO(pages_collapsed); | |
429 | ||
430 | static ssize_t full_scans_show(struct kobject *kobj, | |
431 | struct kobj_attribute *attr, | |
432 | char *buf) | |
433 | { | |
434 | return sprintf(buf, "%u\n", khugepaged_full_scans); | |
435 | } | |
436 | static struct kobj_attribute full_scans_attr = | |
437 | __ATTR_RO(full_scans); | |
438 | ||
439 | static ssize_t khugepaged_defrag_show(struct kobject *kobj, | |
440 | struct kobj_attribute *attr, char *buf) | |
441 | { | |
442 | return single_flag_show(kobj, attr, buf, | |
443 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
444 | } | |
445 | static ssize_t khugepaged_defrag_store(struct kobject *kobj, | |
446 | struct kobj_attribute *attr, | |
447 | const char *buf, size_t count) | |
448 | { | |
449 | return single_flag_store(kobj, attr, buf, count, | |
450 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
451 | } | |
452 | static struct kobj_attribute khugepaged_defrag_attr = | |
453 | __ATTR(defrag, 0644, khugepaged_defrag_show, | |
454 | khugepaged_defrag_store); | |
455 | ||
456 | /* | |
457 | * max_ptes_none controls if khugepaged should collapse hugepages over | |
458 | * any unmapped ptes in turn potentially increasing the memory | |
459 | * footprint of the vmas. When max_ptes_none is 0 khugepaged will not | |
460 | * reduce the available free memory in the system as it | |
461 | * runs. Increasing max_ptes_none will instead potentially reduce the | |
462 | * free memory in the system during the khugepaged scan. | |
463 | */ | |
464 | static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, | |
465 | struct kobj_attribute *attr, | |
466 | char *buf) | |
467 | { | |
468 | return sprintf(buf, "%u\n", khugepaged_max_ptes_none); | |
469 | } | |
470 | static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, | |
471 | struct kobj_attribute *attr, | |
472 | const char *buf, size_t count) | |
473 | { | |
474 | int err; | |
475 | unsigned long max_ptes_none; | |
476 | ||
477 | err = strict_strtoul(buf, 10, &max_ptes_none); | |
478 | if (err || max_ptes_none > HPAGE_PMD_NR-1) | |
479 | return -EINVAL; | |
480 | ||
481 | khugepaged_max_ptes_none = max_ptes_none; | |
482 | ||
483 | return count; | |
484 | } | |
485 | static struct kobj_attribute khugepaged_max_ptes_none_attr = | |
486 | __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, | |
487 | khugepaged_max_ptes_none_store); | |
488 | ||
489 | static struct attribute *khugepaged_attr[] = { | |
490 | &khugepaged_defrag_attr.attr, | |
491 | &khugepaged_max_ptes_none_attr.attr, | |
492 | &pages_to_scan_attr.attr, | |
493 | &pages_collapsed_attr.attr, | |
494 | &full_scans_attr.attr, | |
495 | &scan_sleep_millisecs_attr.attr, | |
496 | &alloc_sleep_millisecs_attr.attr, | |
497 | NULL, | |
498 | }; | |
499 | ||
500 | static struct attribute_group khugepaged_attr_group = { | |
501 | .attrs = khugepaged_attr, | |
502 | .name = "khugepaged", | |
71e3aac0 | 503 | }; |
71e3aac0 | 504 | |
569e5590 | 505 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 506 | { |
71e3aac0 AA |
507 | int err; |
508 | ||
569e5590 SL |
509 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
510 | if (unlikely(!*hugepage_kobj)) { | |
ba76149f | 511 | printk(KERN_ERR "hugepage: failed kobject create\n"); |
569e5590 | 512 | return -ENOMEM; |
ba76149f AA |
513 | } |
514 | ||
569e5590 | 515 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f AA |
516 | if (err) { |
517 | printk(KERN_ERR "hugepage: failed register hugeage group\n"); | |
569e5590 | 518 | goto delete_obj; |
ba76149f AA |
519 | } |
520 | ||
569e5590 | 521 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f AA |
522 | if (err) { |
523 | printk(KERN_ERR "hugepage: failed register hugeage group\n"); | |
569e5590 | 524 | goto remove_hp_group; |
ba76149f | 525 | } |
569e5590 SL |
526 | |
527 | return 0; | |
528 | ||
529 | remove_hp_group: | |
530 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
531 | delete_obj: | |
532 | kobject_put(*hugepage_kobj); | |
533 | return err; | |
534 | } | |
535 | ||
536 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
537 | { | |
538 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
539 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
540 | kobject_put(hugepage_kobj); | |
541 | } | |
542 | #else | |
543 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
544 | { | |
545 | return 0; | |
546 | } | |
547 | ||
548 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
549 | { | |
550 | } | |
551 | #endif /* CONFIG_SYSFS */ | |
552 | ||
553 | static int __init hugepage_init(void) | |
554 | { | |
555 | int err; | |
556 | struct kobject *hugepage_kobj; | |
557 | ||
558 | if (!has_transparent_hugepage()) { | |
559 | transparent_hugepage_flags = 0; | |
560 | return -EINVAL; | |
561 | } | |
562 | ||
563 | err = hugepage_init_sysfs(&hugepage_kobj); | |
564 | if (err) | |
565 | return err; | |
ba76149f | 566 | |
4a6c1297 KS |
567 | err = init_huge_zero_page(); |
568 | if (err) | |
569 | goto out; | |
570 | ||
ba76149f AA |
571 | err = khugepaged_slab_init(); |
572 | if (err) | |
573 | goto out; | |
574 | ||
575 | err = mm_slots_hash_init(); | |
576 | if (err) { | |
577 | khugepaged_slab_free(); | |
578 | goto out; | |
579 | } | |
580 | ||
97562cd2 RR |
581 | /* |
582 | * By default disable transparent hugepages on smaller systems, | |
583 | * where the extra memory used could hurt more than TLB overhead | |
584 | * is likely to save. The admin can still enable it through /sys. | |
585 | */ | |
586 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) | |
587 | transparent_hugepage_flags = 0; | |
588 | ||
ba76149f AA |
589 | start_khugepaged(); |
590 | ||
569e5590 | 591 | return 0; |
ba76149f | 592 | out: |
4a6c1297 KS |
593 | if (huge_zero_pfn) |
594 | __free_page(pfn_to_page(huge_zero_pfn)); | |
569e5590 | 595 | hugepage_exit_sysfs(hugepage_kobj); |
ba76149f | 596 | return err; |
71e3aac0 AA |
597 | } |
598 | module_init(hugepage_init) | |
599 | ||
600 | static int __init setup_transparent_hugepage(char *str) | |
601 | { | |
602 | int ret = 0; | |
603 | if (!str) | |
604 | goto out; | |
605 | if (!strcmp(str, "always")) { | |
606 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
607 | &transparent_hugepage_flags); | |
608 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
609 | &transparent_hugepage_flags); | |
610 | ret = 1; | |
611 | } else if (!strcmp(str, "madvise")) { | |
612 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
613 | &transparent_hugepage_flags); | |
614 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
615 | &transparent_hugepage_flags); | |
616 | ret = 1; | |
617 | } else if (!strcmp(str, "never")) { | |
618 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
619 | &transparent_hugepage_flags); | |
620 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
621 | &transparent_hugepage_flags); | |
622 | ret = 1; | |
623 | } | |
624 | out: | |
625 | if (!ret) | |
626 | printk(KERN_WARNING | |
627 | "transparent_hugepage= cannot parse, ignored\n"); | |
628 | return ret; | |
629 | } | |
630 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
631 | ||
71e3aac0 AA |
632 | static inline pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
633 | { | |
634 | if (likely(vma->vm_flags & VM_WRITE)) | |
635 | pmd = pmd_mkwrite(pmd); | |
636 | return pmd; | |
637 | } | |
638 | ||
b3092b3b BL |
639 | static inline pmd_t mk_huge_pmd(struct page *page, struct vm_area_struct *vma) |
640 | { | |
641 | pmd_t entry; | |
642 | entry = mk_pmd(page, vma->vm_page_prot); | |
643 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
644 | entry = pmd_mkhuge(entry); | |
645 | return entry; | |
646 | } | |
647 | ||
71e3aac0 AA |
648 | static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, |
649 | struct vm_area_struct *vma, | |
650 | unsigned long haddr, pmd_t *pmd, | |
651 | struct page *page) | |
652 | { | |
71e3aac0 AA |
653 | pgtable_t pgtable; |
654 | ||
655 | VM_BUG_ON(!PageCompound(page)); | |
656 | pgtable = pte_alloc_one(mm, haddr); | |
edad9d2c | 657 | if (unlikely(!pgtable)) |
71e3aac0 | 658 | return VM_FAULT_OOM; |
71e3aac0 AA |
659 | |
660 | clear_huge_page(page, haddr, HPAGE_PMD_NR); | |
661 | __SetPageUptodate(page); | |
662 | ||
663 | spin_lock(&mm->page_table_lock); | |
664 | if (unlikely(!pmd_none(*pmd))) { | |
665 | spin_unlock(&mm->page_table_lock); | |
b9bbfbe3 | 666 | mem_cgroup_uncharge_page(page); |
71e3aac0 AA |
667 | put_page(page); |
668 | pte_free(mm, pgtable); | |
669 | } else { | |
670 | pmd_t entry; | |
b3092b3b | 671 | entry = mk_huge_pmd(page, vma); |
71e3aac0 AA |
672 | /* |
673 | * The spinlocking to take the lru_lock inside | |
674 | * page_add_new_anon_rmap() acts as a full memory | |
675 | * barrier to be sure clear_huge_page writes become | |
676 | * visible after the set_pmd_at() write. | |
677 | */ | |
678 | page_add_new_anon_rmap(page, vma, haddr); | |
679 | set_pmd_at(mm, haddr, pmd, entry); | |
e3ebcf64 | 680 | pgtable_trans_huge_deposit(mm, pgtable); |
71e3aac0 | 681 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
1c641e84 | 682 | mm->nr_ptes++; |
71e3aac0 AA |
683 | spin_unlock(&mm->page_table_lock); |
684 | } | |
685 | ||
aa2e878e | 686 | return 0; |
71e3aac0 AA |
687 | } |
688 | ||
cc5d462f | 689 | static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) |
0bbbc0b3 | 690 | { |
cc5d462f | 691 | return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; |
0bbbc0b3 AA |
692 | } |
693 | ||
694 | static inline struct page *alloc_hugepage_vma(int defrag, | |
695 | struct vm_area_struct *vma, | |
cc5d462f AK |
696 | unsigned long haddr, int nd, |
697 | gfp_t extra_gfp) | |
0bbbc0b3 | 698 | { |
cc5d462f | 699 | return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), |
5c4b4be3 | 700 | HPAGE_PMD_ORDER, vma, haddr, nd); |
0bbbc0b3 AA |
701 | } |
702 | ||
703 | #ifndef CONFIG_NUMA | |
71e3aac0 AA |
704 | static inline struct page *alloc_hugepage(int defrag) |
705 | { | |
cc5d462f | 706 | return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), |
71e3aac0 AA |
707 | HPAGE_PMD_ORDER); |
708 | } | |
0bbbc0b3 | 709 | #endif |
71e3aac0 | 710 | |
fc9fe822 KS |
711 | static void set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm, |
712 | struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd) | |
713 | { | |
714 | pmd_t entry; | |
715 | entry = pfn_pmd(huge_zero_pfn, vma->vm_page_prot); | |
716 | entry = pmd_wrprotect(entry); | |
717 | entry = pmd_mkhuge(entry); | |
718 | set_pmd_at(mm, haddr, pmd, entry); | |
719 | pgtable_trans_huge_deposit(mm, pgtable); | |
720 | mm->nr_ptes++; | |
721 | } | |
722 | ||
71e3aac0 AA |
723 | int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
724 | unsigned long address, pmd_t *pmd, | |
725 | unsigned int flags) | |
726 | { | |
727 | struct page *page; | |
728 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
729 | pte_t *pte; | |
730 | ||
731 | if (haddr >= vma->vm_start && haddr + HPAGE_PMD_SIZE <= vma->vm_end) { | |
732 | if (unlikely(anon_vma_prepare(vma))) | |
733 | return VM_FAULT_OOM; | |
ba76149f AA |
734 | if (unlikely(khugepaged_enter(vma))) |
735 | return VM_FAULT_OOM; | |
0bbbc0b3 | 736 | page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 737 | vma, haddr, numa_node_id(), 0); |
81ab4201 AK |
738 | if (unlikely(!page)) { |
739 | count_vm_event(THP_FAULT_FALLBACK); | |
71e3aac0 | 740 | goto out; |
81ab4201 AK |
741 | } |
742 | count_vm_event(THP_FAULT_ALLOC); | |
b9bbfbe3 AA |
743 | if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { |
744 | put_page(page); | |
745 | goto out; | |
746 | } | |
edad9d2c DR |
747 | if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, |
748 | page))) { | |
749 | mem_cgroup_uncharge_page(page); | |
750 | put_page(page); | |
751 | goto out; | |
752 | } | |
71e3aac0 | 753 | |
edad9d2c | 754 | return 0; |
71e3aac0 AA |
755 | } |
756 | out: | |
757 | /* | |
758 | * Use __pte_alloc instead of pte_alloc_map, because we can't | |
759 | * run pte_offset_map on the pmd, if an huge pmd could | |
760 | * materialize from under us from a different thread. | |
761 | */ | |
762 | if (unlikely(__pte_alloc(mm, vma, pmd, address))) | |
763 | return VM_FAULT_OOM; | |
764 | /* if an huge pmd materialized from under us just retry later */ | |
765 | if (unlikely(pmd_trans_huge(*pmd))) | |
766 | return 0; | |
767 | /* | |
768 | * A regular pmd is established and it can't morph into a huge pmd | |
769 | * from under us anymore at this point because we hold the mmap_sem | |
770 | * read mode and khugepaged takes it in write mode. So now it's | |
771 | * safe to run pte_offset_map(). | |
772 | */ | |
773 | pte = pte_offset_map(pmd, address); | |
774 | return handle_pte_fault(mm, vma, address, pte, pmd, flags); | |
775 | } | |
776 | ||
777 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
778 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
779 | struct vm_area_struct *vma) | |
780 | { | |
781 | struct page *src_page; | |
782 | pmd_t pmd; | |
783 | pgtable_t pgtable; | |
784 | int ret; | |
785 | ||
786 | ret = -ENOMEM; | |
787 | pgtable = pte_alloc_one(dst_mm, addr); | |
788 | if (unlikely(!pgtable)) | |
789 | goto out; | |
790 | ||
791 | spin_lock(&dst_mm->page_table_lock); | |
792 | spin_lock_nested(&src_mm->page_table_lock, SINGLE_DEPTH_NESTING); | |
793 | ||
794 | ret = -EAGAIN; | |
795 | pmd = *src_pmd; | |
796 | if (unlikely(!pmd_trans_huge(pmd))) { | |
797 | pte_free(dst_mm, pgtable); | |
798 | goto out_unlock; | |
799 | } | |
fc9fe822 KS |
800 | /* |
801 | * mm->page_table_lock is enough to be sure that huge zero pmd is not | |
802 | * under splitting since we don't split the page itself, only pmd to | |
803 | * a page table. | |
804 | */ | |
805 | if (is_huge_zero_pmd(pmd)) { | |
806 | set_huge_zero_page(pgtable, dst_mm, vma, addr, dst_pmd); | |
807 | ret = 0; | |
808 | goto out_unlock; | |
809 | } | |
71e3aac0 AA |
810 | if (unlikely(pmd_trans_splitting(pmd))) { |
811 | /* split huge page running from under us */ | |
812 | spin_unlock(&src_mm->page_table_lock); | |
813 | spin_unlock(&dst_mm->page_table_lock); | |
814 | pte_free(dst_mm, pgtable); | |
815 | ||
816 | wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ | |
817 | goto out; | |
818 | } | |
819 | src_page = pmd_page(pmd); | |
820 | VM_BUG_ON(!PageHead(src_page)); | |
821 | get_page(src_page); | |
822 | page_dup_rmap(src_page); | |
823 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
824 | ||
825 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
826 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
827 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
e3ebcf64 | 828 | pgtable_trans_huge_deposit(dst_mm, pgtable); |
1c641e84 | 829 | dst_mm->nr_ptes++; |
71e3aac0 AA |
830 | |
831 | ret = 0; | |
832 | out_unlock: | |
833 | spin_unlock(&src_mm->page_table_lock); | |
834 | spin_unlock(&dst_mm->page_table_lock); | |
835 | out: | |
836 | return ret; | |
837 | } | |
838 | ||
a1dd450b WD |
839 | void huge_pmd_set_accessed(struct mm_struct *mm, |
840 | struct vm_area_struct *vma, | |
841 | unsigned long address, | |
842 | pmd_t *pmd, pmd_t orig_pmd, | |
843 | int dirty) | |
844 | { | |
845 | pmd_t entry; | |
846 | unsigned long haddr; | |
847 | ||
848 | spin_lock(&mm->page_table_lock); | |
849 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
850 | goto unlock; | |
851 | ||
852 | entry = pmd_mkyoung(orig_pmd); | |
853 | haddr = address & HPAGE_PMD_MASK; | |
854 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, dirty)) | |
855 | update_mmu_cache_pmd(vma, address, pmd); | |
856 | ||
857 | unlock: | |
858 | spin_unlock(&mm->page_table_lock); | |
859 | } | |
860 | ||
93b4796d KS |
861 | static int do_huge_pmd_wp_zero_page_fallback(struct mm_struct *mm, |
862 | struct vm_area_struct *vma, unsigned long address, | |
863 | pmd_t *pmd, unsigned long haddr) | |
864 | { | |
865 | pgtable_t pgtable; | |
866 | pmd_t _pmd; | |
867 | struct page *page; | |
868 | int i, ret = 0; | |
869 | unsigned long mmun_start; /* For mmu_notifiers */ | |
870 | unsigned long mmun_end; /* For mmu_notifiers */ | |
871 | ||
872 | page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
873 | if (!page) { | |
874 | ret |= VM_FAULT_OOM; | |
875 | goto out; | |
876 | } | |
877 | ||
878 | if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) { | |
879 | put_page(page); | |
880 | ret |= VM_FAULT_OOM; | |
881 | goto out; | |
882 | } | |
883 | ||
884 | clear_user_highpage(page, address); | |
885 | __SetPageUptodate(page); | |
886 | ||
887 | mmun_start = haddr; | |
888 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
889 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
890 | ||
891 | spin_lock(&mm->page_table_lock); | |
892 | pmdp_clear_flush(vma, haddr, pmd); | |
893 | /* leave pmd empty until pte is filled */ | |
894 | ||
895 | pgtable = pgtable_trans_huge_withdraw(mm); | |
896 | pmd_populate(mm, &_pmd, pgtable); | |
897 | ||
898 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
899 | pte_t *pte, entry; | |
900 | if (haddr == (address & PAGE_MASK)) { | |
901 | entry = mk_pte(page, vma->vm_page_prot); | |
902 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
903 | page_add_new_anon_rmap(page, vma, haddr); | |
904 | } else { | |
905 | entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); | |
906 | entry = pte_mkspecial(entry); | |
907 | } | |
908 | pte = pte_offset_map(&_pmd, haddr); | |
909 | VM_BUG_ON(!pte_none(*pte)); | |
910 | set_pte_at(mm, haddr, pte, entry); | |
911 | pte_unmap(pte); | |
912 | } | |
913 | smp_wmb(); /* make pte visible before pmd */ | |
914 | pmd_populate(mm, pmd, pgtable); | |
915 | spin_unlock(&mm->page_table_lock); | |
916 | inc_mm_counter(mm, MM_ANONPAGES); | |
917 | ||
918 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
919 | ||
920 | ret |= VM_FAULT_WRITE; | |
921 | out: | |
922 | return ret; | |
923 | } | |
924 | ||
71e3aac0 AA |
925 | static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, |
926 | struct vm_area_struct *vma, | |
927 | unsigned long address, | |
928 | pmd_t *pmd, pmd_t orig_pmd, | |
929 | struct page *page, | |
930 | unsigned long haddr) | |
931 | { | |
932 | pgtable_t pgtable; | |
933 | pmd_t _pmd; | |
934 | int ret = 0, i; | |
935 | struct page **pages; | |
2ec74c3e SG |
936 | unsigned long mmun_start; /* For mmu_notifiers */ |
937 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
938 | |
939 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
940 | GFP_KERNEL); | |
941 | if (unlikely(!pages)) { | |
942 | ret |= VM_FAULT_OOM; | |
943 | goto out; | |
944 | } | |
945 | ||
946 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
cc5d462f AK |
947 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | |
948 | __GFP_OTHER_NODE, | |
19ee151e | 949 | vma, address, page_to_nid(page)); |
b9bbfbe3 AA |
950 | if (unlikely(!pages[i] || |
951 | mem_cgroup_newpage_charge(pages[i], mm, | |
952 | GFP_KERNEL))) { | |
953 | if (pages[i]) | |
71e3aac0 | 954 | put_page(pages[i]); |
b9bbfbe3 AA |
955 | mem_cgroup_uncharge_start(); |
956 | while (--i >= 0) { | |
957 | mem_cgroup_uncharge_page(pages[i]); | |
958 | put_page(pages[i]); | |
959 | } | |
960 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
961 | kfree(pages); |
962 | ret |= VM_FAULT_OOM; | |
963 | goto out; | |
964 | } | |
965 | } | |
966 | ||
967 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
968 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 969 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
970 | __SetPageUptodate(pages[i]); |
971 | cond_resched(); | |
972 | } | |
973 | ||
2ec74c3e SG |
974 | mmun_start = haddr; |
975 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
976 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
977 | ||
71e3aac0 AA |
978 | spin_lock(&mm->page_table_lock); |
979 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
980 | goto out_free_pages; | |
981 | VM_BUG_ON(!PageHead(page)); | |
982 | ||
2ec74c3e | 983 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
984 | /* leave pmd empty until pte is filled */ |
985 | ||
e3ebcf64 | 986 | pgtable = pgtable_trans_huge_withdraw(mm); |
71e3aac0 AA |
987 | pmd_populate(mm, &_pmd, pgtable); |
988 | ||
989 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
990 | pte_t *pte, entry; | |
991 | entry = mk_pte(pages[i], vma->vm_page_prot); | |
992 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
993 | page_add_new_anon_rmap(pages[i], vma, haddr); | |
994 | pte = pte_offset_map(&_pmd, haddr); | |
995 | VM_BUG_ON(!pte_none(*pte)); | |
996 | set_pte_at(mm, haddr, pte, entry); | |
997 | pte_unmap(pte); | |
998 | } | |
999 | kfree(pages); | |
1000 | ||
71e3aac0 AA |
1001 | smp_wmb(); /* make pte visible before pmd */ |
1002 | pmd_populate(mm, pmd, pgtable); | |
1003 | page_remove_rmap(page); | |
1004 | spin_unlock(&mm->page_table_lock); | |
1005 | ||
2ec74c3e SG |
1006 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
1007 | ||
71e3aac0 AA |
1008 | ret |= VM_FAULT_WRITE; |
1009 | put_page(page); | |
1010 | ||
1011 | out: | |
1012 | return ret; | |
1013 | ||
1014 | out_free_pages: | |
1015 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 1016 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
b9bbfbe3 AA |
1017 | mem_cgroup_uncharge_start(); |
1018 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
1019 | mem_cgroup_uncharge_page(pages[i]); | |
71e3aac0 | 1020 | put_page(pages[i]); |
b9bbfbe3 AA |
1021 | } |
1022 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
1023 | kfree(pages); |
1024 | goto out; | |
1025 | } | |
1026 | ||
1027 | int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
1028 | unsigned long address, pmd_t *pmd, pmd_t orig_pmd) | |
1029 | { | |
1030 | int ret = 0; | |
93b4796d | 1031 | struct page *page = NULL, *new_page; |
71e3aac0 | 1032 | unsigned long haddr; |
2ec74c3e SG |
1033 | unsigned long mmun_start; /* For mmu_notifiers */ |
1034 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
1035 | |
1036 | VM_BUG_ON(!vma->anon_vma); | |
93b4796d KS |
1037 | haddr = address & HPAGE_PMD_MASK; |
1038 | if (is_huge_zero_pmd(orig_pmd)) | |
1039 | goto alloc; | |
71e3aac0 AA |
1040 | spin_lock(&mm->page_table_lock); |
1041 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
1042 | goto out_unlock; | |
1043 | ||
1044 | page = pmd_page(orig_pmd); | |
1045 | VM_BUG_ON(!PageCompound(page) || !PageHead(page)); | |
71e3aac0 AA |
1046 | if (page_mapcount(page) == 1) { |
1047 | pmd_t entry; | |
1048 | entry = pmd_mkyoung(orig_pmd); | |
1049 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
1050 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) | |
b113da65 | 1051 | update_mmu_cache_pmd(vma, address, pmd); |
71e3aac0 AA |
1052 | ret |= VM_FAULT_WRITE; |
1053 | goto out_unlock; | |
1054 | } | |
1055 | get_page(page); | |
1056 | spin_unlock(&mm->page_table_lock); | |
93b4796d | 1057 | alloc: |
71e3aac0 AA |
1058 | if (transparent_hugepage_enabled(vma) && |
1059 | !transparent_hugepage_debug_cow()) | |
0bbbc0b3 | 1060 | new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 1061 | vma, haddr, numa_node_id(), 0); |
71e3aac0 AA |
1062 | else |
1063 | new_page = NULL; | |
1064 | ||
1065 | if (unlikely(!new_page)) { | |
81ab4201 | 1066 | count_vm_event(THP_FAULT_FALLBACK); |
93b4796d KS |
1067 | if (is_huge_zero_pmd(orig_pmd)) { |
1068 | ret = do_huge_pmd_wp_zero_page_fallback(mm, vma, | |
1069 | address, pmd, haddr); | |
1070 | } else { | |
1071 | ret = do_huge_pmd_wp_page_fallback(mm, vma, address, | |
1072 | pmd, orig_pmd, page, haddr); | |
1073 | if (ret & VM_FAULT_OOM) | |
1074 | split_huge_page(page); | |
1075 | put_page(page); | |
1076 | } | |
71e3aac0 AA |
1077 | goto out; |
1078 | } | |
81ab4201 | 1079 | count_vm_event(THP_FAULT_ALLOC); |
71e3aac0 | 1080 | |
b9bbfbe3 AA |
1081 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { |
1082 | put_page(new_page); | |
93b4796d KS |
1083 | if (page) { |
1084 | split_huge_page(page); | |
1085 | put_page(page); | |
1086 | } | |
b9bbfbe3 AA |
1087 | ret |= VM_FAULT_OOM; |
1088 | goto out; | |
1089 | } | |
1090 | ||
93b4796d KS |
1091 | if (is_huge_zero_pmd(orig_pmd)) |
1092 | clear_huge_page(new_page, haddr, HPAGE_PMD_NR); | |
1093 | else | |
1094 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); | |
71e3aac0 AA |
1095 | __SetPageUptodate(new_page); |
1096 | ||
2ec74c3e SG |
1097 | mmun_start = haddr; |
1098 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
1099 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
1100 | ||
71e3aac0 | 1101 | spin_lock(&mm->page_table_lock); |
93b4796d KS |
1102 | if (page) |
1103 | put_page(page); | |
b9bbfbe3 | 1104 | if (unlikely(!pmd_same(*pmd, orig_pmd))) { |
6f60b69d | 1105 | spin_unlock(&mm->page_table_lock); |
b9bbfbe3 | 1106 | mem_cgroup_uncharge_page(new_page); |
71e3aac0 | 1107 | put_page(new_page); |
2ec74c3e | 1108 | goto out_mn; |
b9bbfbe3 | 1109 | } else { |
71e3aac0 | 1110 | pmd_t entry; |
b3092b3b | 1111 | entry = mk_huge_pmd(new_page, vma); |
2ec74c3e | 1112 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
1113 | page_add_new_anon_rmap(new_page, vma, haddr); |
1114 | set_pmd_at(mm, haddr, pmd, entry); | |
b113da65 | 1115 | update_mmu_cache_pmd(vma, address, pmd); |
93b4796d KS |
1116 | if (is_huge_zero_pmd(orig_pmd)) |
1117 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
1118 | else { | |
1119 | VM_BUG_ON(!PageHead(page)); | |
1120 | page_remove_rmap(page); | |
1121 | put_page(page); | |
1122 | } | |
71e3aac0 AA |
1123 | ret |= VM_FAULT_WRITE; |
1124 | } | |
71e3aac0 | 1125 | spin_unlock(&mm->page_table_lock); |
2ec74c3e SG |
1126 | out_mn: |
1127 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
1128 | out: |
1129 | return ret; | |
2ec74c3e SG |
1130 | out_unlock: |
1131 | spin_unlock(&mm->page_table_lock); | |
1132 | return ret; | |
71e3aac0 AA |
1133 | } |
1134 | ||
b676b293 | 1135 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
1136 | unsigned long addr, |
1137 | pmd_t *pmd, | |
1138 | unsigned int flags) | |
1139 | { | |
b676b293 | 1140 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
1141 | struct page *page = NULL; |
1142 | ||
1143 | assert_spin_locked(&mm->page_table_lock); | |
1144 | ||
1145 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) | |
1146 | goto out; | |
1147 | ||
1148 | page = pmd_page(*pmd); | |
1149 | VM_BUG_ON(!PageHead(page)); | |
1150 | if (flags & FOLL_TOUCH) { | |
1151 | pmd_t _pmd; | |
1152 | /* | |
1153 | * We should set the dirty bit only for FOLL_WRITE but | |
1154 | * for now the dirty bit in the pmd is meaningless. | |
1155 | * And if the dirty bit will become meaningful and | |
1156 | * we'll only set it with FOLL_WRITE, an atomic | |
1157 | * set_bit will be required on the pmd to set the | |
1158 | * young bit, instead of the current set_pmd_at. | |
1159 | */ | |
1160 | _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); | |
1161 | set_pmd_at(mm, addr & HPAGE_PMD_MASK, pmd, _pmd); | |
1162 | } | |
b676b293 DR |
1163 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
1164 | if (page->mapping && trylock_page(page)) { | |
1165 | lru_add_drain(); | |
1166 | if (page->mapping) | |
1167 | mlock_vma_page(page); | |
1168 | unlock_page(page); | |
1169 | } | |
1170 | } | |
71e3aac0 AA |
1171 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
1172 | VM_BUG_ON(!PageCompound(page)); | |
1173 | if (flags & FOLL_GET) | |
70b50f94 | 1174 | get_page_foll(page); |
71e3aac0 AA |
1175 | |
1176 | out: | |
1177 | return page; | |
1178 | } | |
1179 | ||
1180 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, | |
f21760b1 | 1181 | pmd_t *pmd, unsigned long addr) |
71e3aac0 AA |
1182 | { |
1183 | int ret = 0; | |
1184 | ||
025c5b24 NH |
1185 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1186 | struct page *page; | |
1187 | pgtable_t pgtable; | |
f5c8ad47 | 1188 | pmd_t orig_pmd; |
e3ebcf64 | 1189 | pgtable = pgtable_trans_huge_withdraw(tlb->mm); |
f5c8ad47 | 1190 | orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); |
025c5b24 | 1191 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
479f0abb KS |
1192 | if (is_huge_zero_pmd(orig_pmd)) { |
1193 | tlb->mm->nr_ptes--; | |
1194 | spin_unlock(&tlb->mm->page_table_lock); | |
1195 | } else { | |
1196 | page = pmd_page(orig_pmd); | |
1197 | page_remove_rmap(page); | |
1198 | VM_BUG_ON(page_mapcount(page) < 0); | |
1199 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); | |
1200 | VM_BUG_ON(!PageHead(page)); | |
1201 | tlb->mm->nr_ptes--; | |
1202 | spin_unlock(&tlb->mm->page_table_lock); | |
1203 | tlb_remove_page(tlb, page); | |
1204 | } | |
025c5b24 NH |
1205 | pte_free(tlb->mm, pgtable); |
1206 | ret = 1; | |
1207 | } | |
71e3aac0 AA |
1208 | return ret; |
1209 | } | |
1210 | ||
0ca1634d JW |
1211 | int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
1212 | unsigned long addr, unsigned long end, | |
1213 | unsigned char *vec) | |
1214 | { | |
1215 | int ret = 0; | |
1216 | ||
025c5b24 NH |
1217 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1218 | /* | |
1219 | * All logical pages in the range are present | |
1220 | * if backed by a huge page. | |
1221 | */ | |
0ca1634d | 1222 | spin_unlock(&vma->vm_mm->page_table_lock); |
025c5b24 NH |
1223 | memset(vec, 1, (end - addr) >> PAGE_SHIFT); |
1224 | ret = 1; | |
1225 | } | |
0ca1634d JW |
1226 | |
1227 | return ret; | |
1228 | } | |
1229 | ||
37a1c49a AA |
1230 | int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, |
1231 | unsigned long old_addr, | |
1232 | unsigned long new_addr, unsigned long old_end, | |
1233 | pmd_t *old_pmd, pmd_t *new_pmd) | |
1234 | { | |
1235 | int ret = 0; | |
1236 | pmd_t pmd; | |
1237 | ||
1238 | struct mm_struct *mm = vma->vm_mm; | |
1239 | ||
1240 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1241 | (new_addr & ~HPAGE_PMD_MASK) || | |
1242 | old_end - old_addr < HPAGE_PMD_SIZE || | |
1243 | (new_vma->vm_flags & VM_NOHUGEPAGE)) | |
1244 | goto out; | |
1245 | ||
1246 | /* | |
1247 | * The destination pmd shouldn't be established, free_pgtables() | |
1248 | * should have release it. | |
1249 | */ | |
1250 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1251 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
1252 | goto out; | |
1253 | } | |
1254 | ||
025c5b24 NH |
1255 | ret = __pmd_trans_huge_lock(old_pmd, vma); |
1256 | if (ret == 1) { | |
1257 | pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); | |
1258 | VM_BUG_ON(!pmd_none(*new_pmd)); | |
1259 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
37a1c49a AA |
1260 | spin_unlock(&mm->page_table_lock); |
1261 | } | |
1262 | out: | |
1263 | return ret; | |
1264 | } | |
1265 | ||
cd7548ab JW |
1266 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
1267 | unsigned long addr, pgprot_t newprot) | |
1268 | { | |
1269 | struct mm_struct *mm = vma->vm_mm; | |
1270 | int ret = 0; | |
1271 | ||
025c5b24 NH |
1272 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1273 | pmd_t entry; | |
1274 | entry = pmdp_get_and_clear(mm, addr, pmd); | |
1275 | entry = pmd_modify(entry, newprot); | |
cad7f613 | 1276 | BUG_ON(pmd_write(entry)); |
025c5b24 NH |
1277 | set_pmd_at(mm, addr, pmd, entry); |
1278 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1279 | ret = 1; | |
1280 | } | |
1281 | ||
1282 | return ret; | |
1283 | } | |
1284 | ||
1285 | /* | |
1286 | * Returns 1 if a given pmd maps a stable (not under splitting) thp. | |
1287 | * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. | |
1288 | * | |
1289 | * Note that if it returns 1, this routine returns without unlocking page | |
1290 | * table locks. So callers must unlock them. | |
1291 | */ | |
1292 | int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) | |
1293 | { | |
1294 | spin_lock(&vma->vm_mm->page_table_lock); | |
cd7548ab JW |
1295 | if (likely(pmd_trans_huge(*pmd))) { |
1296 | if (unlikely(pmd_trans_splitting(*pmd))) { | |
025c5b24 | 1297 | spin_unlock(&vma->vm_mm->page_table_lock); |
cd7548ab | 1298 | wait_split_huge_page(vma->anon_vma, pmd); |
025c5b24 | 1299 | return -1; |
cd7548ab | 1300 | } else { |
025c5b24 NH |
1301 | /* Thp mapped by 'pmd' is stable, so we can |
1302 | * handle it as it is. */ | |
1303 | return 1; | |
cd7548ab | 1304 | } |
025c5b24 NH |
1305 | } |
1306 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1307 | return 0; | |
cd7548ab JW |
1308 | } |
1309 | ||
71e3aac0 AA |
1310 | pmd_t *page_check_address_pmd(struct page *page, |
1311 | struct mm_struct *mm, | |
1312 | unsigned long address, | |
1313 | enum page_check_address_pmd_flag flag) | |
1314 | { | |
71e3aac0 AA |
1315 | pmd_t *pmd, *ret = NULL; |
1316 | ||
1317 | if (address & ~HPAGE_PMD_MASK) | |
1318 | goto out; | |
1319 | ||
6219049a BL |
1320 | pmd = mm_find_pmd(mm, address); |
1321 | if (!pmd) | |
71e3aac0 | 1322 | goto out; |
71e3aac0 AA |
1323 | if (pmd_none(*pmd)) |
1324 | goto out; | |
1325 | if (pmd_page(*pmd) != page) | |
1326 | goto out; | |
94fcc585 AA |
1327 | /* |
1328 | * split_vma() may create temporary aliased mappings. There is | |
1329 | * no risk as long as all huge pmd are found and have their | |
1330 | * splitting bit set before __split_huge_page_refcount | |
1331 | * runs. Finding the same huge pmd more than once during the | |
1332 | * same rmap walk is not a problem. | |
1333 | */ | |
1334 | if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && | |
1335 | pmd_trans_splitting(*pmd)) | |
1336 | goto out; | |
71e3aac0 AA |
1337 | if (pmd_trans_huge(*pmd)) { |
1338 | VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && | |
1339 | !pmd_trans_splitting(*pmd)); | |
1340 | ret = pmd; | |
1341 | } | |
1342 | out: | |
1343 | return ret; | |
1344 | } | |
1345 | ||
1346 | static int __split_huge_page_splitting(struct page *page, | |
1347 | struct vm_area_struct *vma, | |
1348 | unsigned long address) | |
1349 | { | |
1350 | struct mm_struct *mm = vma->vm_mm; | |
1351 | pmd_t *pmd; | |
1352 | int ret = 0; | |
2ec74c3e SG |
1353 | /* For mmu_notifiers */ |
1354 | const unsigned long mmun_start = address; | |
1355 | const unsigned long mmun_end = address + HPAGE_PMD_SIZE; | |
71e3aac0 | 1356 | |
2ec74c3e | 1357 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1358 | spin_lock(&mm->page_table_lock); |
1359 | pmd = page_check_address_pmd(page, mm, address, | |
1360 | PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG); | |
1361 | if (pmd) { | |
1362 | /* | |
1363 | * We can't temporarily set the pmd to null in order | |
1364 | * to split it, the pmd must remain marked huge at all | |
1365 | * times or the VM won't take the pmd_trans_huge paths | |
2b575eb6 | 1366 | * and it won't wait on the anon_vma->root->mutex to |
71e3aac0 AA |
1367 | * serialize against split_huge_page*. |
1368 | */ | |
2ec74c3e | 1369 | pmdp_splitting_flush(vma, address, pmd); |
71e3aac0 AA |
1370 | ret = 1; |
1371 | } | |
1372 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 1373 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1374 | |
1375 | return ret; | |
1376 | } | |
1377 | ||
1378 | static void __split_huge_page_refcount(struct page *page) | |
1379 | { | |
1380 | int i; | |
71e3aac0 | 1381 | struct zone *zone = page_zone(page); |
fa9add64 | 1382 | struct lruvec *lruvec; |
70b50f94 | 1383 | int tail_count = 0; |
71e3aac0 AA |
1384 | |
1385 | /* prevent PageLRU to go away from under us, and freeze lru stats */ | |
1386 | spin_lock_irq(&zone->lru_lock); | |
fa9add64 HD |
1387 | lruvec = mem_cgroup_page_lruvec(page, zone); |
1388 | ||
71e3aac0 | 1389 | compound_lock(page); |
e94c8a9c KH |
1390 | /* complete memcg works before add pages to LRU */ |
1391 | mem_cgroup_split_huge_fixup(page); | |
71e3aac0 | 1392 | |
45676885 | 1393 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
71e3aac0 AA |
1394 | struct page *page_tail = page + i; |
1395 | ||
70b50f94 AA |
1396 | /* tail_page->_mapcount cannot change */ |
1397 | BUG_ON(page_mapcount(page_tail) < 0); | |
1398 | tail_count += page_mapcount(page_tail); | |
1399 | /* check for overflow */ | |
1400 | BUG_ON(tail_count < 0); | |
1401 | BUG_ON(atomic_read(&page_tail->_count) != 0); | |
1402 | /* | |
1403 | * tail_page->_count is zero and not changing from | |
1404 | * under us. But get_page_unless_zero() may be running | |
1405 | * from under us on the tail_page. If we used | |
1406 | * atomic_set() below instead of atomic_add(), we | |
1407 | * would then run atomic_set() concurrently with | |
1408 | * get_page_unless_zero(), and atomic_set() is | |
1409 | * implemented in C not using locked ops. spin_unlock | |
1410 | * on x86 sometime uses locked ops because of PPro | |
1411 | * errata 66, 92, so unless somebody can guarantee | |
1412 | * atomic_set() here would be safe on all archs (and | |
1413 | * not only on x86), it's safer to use atomic_add(). | |
1414 | */ | |
1415 | atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, | |
1416 | &page_tail->_count); | |
71e3aac0 AA |
1417 | |
1418 | /* after clearing PageTail the gup refcount can be released */ | |
1419 | smp_mb(); | |
1420 | ||
a6d30ddd JD |
1421 | /* |
1422 | * retain hwpoison flag of the poisoned tail page: | |
1423 | * fix for the unsuitable process killed on Guest Machine(KVM) | |
1424 | * by the memory-failure. | |
1425 | */ | |
1426 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; | |
71e3aac0 AA |
1427 | page_tail->flags |= (page->flags & |
1428 | ((1L << PG_referenced) | | |
1429 | (1L << PG_swapbacked) | | |
1430 | (1L << PG_mlocked) | | |
1431 | (1L << PG_uptodate))); | |
1432 | page_tail->flags |= (1L << PG_dirty); | |
1433 | ||
70b50f94 | 1434 | /* clear PageTail before overwriting first_page */ |
71e3aac0 AA |
1435 | smp_wmb(); |
1436 | ||
1437 | /* | |
1438 | * __split_huge_page_splitting() already set the | |
1439 | * splitting bit in all pmd that could map this | |
1440 | * hugepage, that will ensure no CPU can alter the | |
1441 | * mapcount on the head page. The mapcount is only | |
1442 | * accounted in the head page and it has to be | |
1443 | * transferred to all tail pages in the below code. So | |
1444 | * for this code to be safe, the split the mapcount | |
1445 | * can't change. But that doesn't mean userland can't | |
1446 | * keep changing and reading the page contents while | |
1447 | * we transfer the mapcount, so the pmd splitting | |
1448 | * status is achieved setting a reserved bit in the | |
1449 | * pmd, not by clearing the present bit. | |
1450 | */ | |
71e3aac0 AA |
1451 | page_tail->_mapcount = page->_mapcount; |
1452 | ||
1453 | BUG_ON(page_tail->mapping); | |
1454 | page_tail->mapping = page->mapping; | |
1455 | ||
45676885 | 1456 | page_tail->index = page->index + i; |
71e3aac0 AA |
1457 | |
1458 | BUG_ON(!PageAnon(page_tail)); | |
1459 | BUG_ON(!PageUptodate(page_tail)); | |
1460 | BUG_ON(!PageDirty(page_tail)); | |
1461 | BUG_ON(!PageSwapBacked(page_tail)); | |
1462 | ||
fa9add64 | 1463 | lru_add_page_tail(page, page_tail, lruvec); |
71e3aac0 | 1464 | } |
70b50f94 AA |
1465 | atomic_sub(tail_count, &page->_count); |
1466 | BUG_ON(atomic_read(&page->_count) <= 0); | |
71e3aac0 | 1467 | |
fa9add64 | 1468 | __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); |
79134171 AA |
1469 | __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR); |
1470 | ||
71e3aac0 AA |
1471 | ClearPageCompound(page); |
1472 | compound_unlock(page); | |
1473 | spin_unlock_irq(&zone->lru_lock); | |
1474 | ||
1475 | for (i = 1; i < HPAGE_PMD_NR; i++) { | |
1476 | struct page *page_tail = page + i; | |
1477 | BUG_ON(page_count(page_tail) <= 0); | |
1478 | /* | |
1479 | * Tail pages may be freed if there wasn't any mapping | |
1480 | * like if add_to_swap() is running on a lru page that | |
1481 | * had its mapping zapped. And freeing these pages | |
1482 | * requires taking the lru_lock so we do the put_page | |
1483 | * of the tail pages after the split is complete. | |
1484 | */ | |
1485 | put_page(page_tail); | |
1486 | } | |
1487 | ||
1488 | /* | |
1489 | * Only the head page (now become a regular page) is required | |
1490 | * to be pinned by the caller. | |
1491 | */ | |
1492 | BUG_ON(page_count(page) <= 0); | |
1493 | } | |
1494 | ||
1495 | static int __split_huge_page_map(struct page *page, | |
1496 | struct vm_area_struct *vma, | |
1497 | unsigned long address) | |
1498 | { | |
1499 | struct mm_struct *mm = vma->vm_mm; | |
1500 | pmd_t *pmd, _pmd; | |
1501 | int ret = 0, i; | |
1502 | pgtable_t pgtable; | |
1503 | unsigned long haddr; | |
1504 | ||
1505 | spin_lock(&mm->page_table_lock); | |
1506 | pmd = page_check_address_pmd(page, mm, address, | |
1507 | PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); | |
1508 | if (pmd) { | |
e3ebcf64 | 1509 | pgtable = pgtable_trans_huge_withdraw(mm); |
71e3aac0 AA |
1510 | pmd_populate(mm, &_pmd, pgtable); |
1511 | ||
e3ebcf64 GS |
1512 | haddr = address; |
1513 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
71e3aac0 AA |
1514 | pte_t *pte, entry; |
1515 | BUG_ON(PageCompound(page+i)); | |
1516 | entry = mk_pte(page + i, vma->vm_page_prot); | |
1517 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1518 | if (!pmd_write(*pmd)) | |
1519 | entry = pte_wrprotect(entry); | |
1520 | else | |
1521 | BUG_ON(page_mapcount(page) != 1); | |
1522 | if (!pmd_young(*pmd)) | |
1523 | entry = pte_mkold(entry); | |
1524 | pte = pte_offset_map(&_pmd, haddr); | |
1525 | BUG_ON(!pte_none(*pte)); | |
1526 | set_pte_at(mm, haddr, pte, entry); | |
1527 | pte_unmap(pte); | |
1528 | } | |
1529 | ||
71e3aac0 AA |
1530 | smp_wmb(); /* make pte visible before pmd */ |
1531 | /* | |
1532 | * Up to this point the pmd is present and huge and | |
1533 | * userland has the whole access to the hugepage | |
1534 | * during the split (which happens in place). If we | |
1535 | * overwrite the pmd with the not-huge version | |
1536 | * pointing to the pte here (which of course we could | |
1537 | * if all CPUs were bug free), userland could trigger | |
1538 | * a small page size TLB miss on the small sized TLB | |
1539 | * while the hugepage TLB entry is still established | |
1540 | * in the huge TLB. Some CPU doesn't like that. See | |
1541 | * http://support.amd.com/us/Processor_TechDocs/41322.pdf, | |
1542 | * Erratum 383 on page 93. Intel should be safe but is | |
1543 | * also warns that it's only safe if the permission | |
1544 | * and cache attributes of the two entries loaded in | |
1545 | * the two TLB is identical (which should be the case | |
1546 | * here). But it is generally safer to never allow | |
1547 | * small and huge TLB entries for the same virtual | |
1548 | * address to be loaded simultaneously. So instead of | |
1549 | * doing "pmd_populate(); flush_tlb_range();" we first | |
1550 | * mark the current pmd notpresent (atomically because | |
1551 | * here the pmd_trans_huge and pmd_trans_splitting | |
1552 | * must remain set at all times on the pmd until the | |
1553 | * split is complete for this pmd), then we flush the | |
1554 | * SMP TLB and finally we write the non-huge version | |
1555 | * of the pmd entry with pmd_populate. | |
1556 | */ | |
46dcde73 | 1557 | pmdp_invalidate(vma, address, pmd); |
71e3aac0 AA |
1558 | pmd_populate(mm, pmd, pgtable); |
1559 | ret = 1; | |
1560 | } | |
1561 | spin_unlock(&mm->page_table_lock); | |
1562 | ||
1563 | return ret; | |
1564 | } | |
1565 | ||
2b575eb6 | 1566 | /* must be called with anon_vma->root->mutex hold */ |
71e3aac0 AA |
1567 | static void __split_huge_page(struct page *page, |
1568 | struct anon_vma *anon_vma) | |
1569 | { | |
1570 | int mapcount, mapcount2; | |
bf181b9f | 1571 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); |
71e3aac0 AA |
1572 | struct anon_vma_chain *avc; |
1573 | ||
1574 | BUG_ON(!PageHead(page)); | |
1575 | BUG_ON(PageTail(page)); | |
1576 | ||
1577 | mapcount = 0; | |
bf181b9f | 1578 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1579 | struct vm_area_struct *vma = avc->vma; |
1580 | unsigned long addr = vma_address(page, vma); | |
1581 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1582 | mapcount += __split_huge_page_splitting(page, vma, addr); |
1583 | } | |
05759d38 AA |
1584 | /* |
1585 | * It is critical that new vmas are added to the tail of the | |
1586 | * anon_vma list. This guarantes that if copy_huge_pmd() runs | |
1587 | * and establishes a child pmd before | |
1588 | * __split_huge_page_splitting() freezes the parent pmd (so if | |
1589 | * we fail to prevent copy_huge_pmd() from running until the | |
1590 | * whole __split_huge_page() is complete), we will still see | |
1591 | * the newly established pmd of the child later during the | |
1592 | * walk, to be able to set it as pmd_trans_splitting too. | |
1593 | */ | |
1594 | if (mapcount != page_mapcount(page)) | |
1595 | printk(KERN_ERR "mapcount %d page_mapcount %d\n", | |
1596 | mapcount, page_mapcount(page)); | |
71e3aac0 AA |
1597 | BUG_ON(mapcount != page_mapcount(page)); |
1598 | ||
1599 | __split_huge_page_refcount(page); | |
1600 | ||
1601 | mapcount2 = 0; | |
bf181b9f | 1602 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1603 | struct vm_area_struct *vma = avc->vma; |
1604 | unsigned long addr = vma_address(page, vma); | |
1605 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1606 | mapcount2 += __split_huge_page_map(page, vma, addr); |
1607 | } | |
05759d38 AA |
1608 | if (mapcount != mapcount2) |
1609 | printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", | |
1610 | mapcount, mapcount2, page_mapcount(page)); | |
71e3aac0 AA |
1611 | BUG_ON(mapcount != mapcount2); |
1612 | } | |
1613 | ||
1614 | int split_huge_page(struct page *page) | |
1615 | { | |
1616 | struct anon_vma *anon_vma; | |
1617 | int ret = 1; | |
1618 | ||
1619 | BUG_ON(!PageAnon(page)); | |
1620 | anon_vma = page_lock_anon_vma(page); | |
1621 | if (!anon_vma) | |
1622 | goto out; | |
1623 | ret = 0; | |
1624 | if (!PageCompound(page)) | |
1625 | goto out_unlock; | |
1626 | ||
1627 | BUG_ON(!PageSwapBacked(page)); | |
1628 | __split_huge_page(page, anon_vma); | |
81ab4201 | 1629 | count_vm_event(THP_SPLIT); |
71e3aac0 AA |
1630 | |
1631 | BUG_ON(PageCompound(page)); | |
1632 | out_unlock: | |
1633 | page_unlock_anon_vma(anon_vma); | |
1634 | out: | |
1635 | return ret; | |
1636 | } | |
1637 | ||
4b6e1e37 | 1638 | #define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE) |
78f11a25 | 1639 | |
60ab3244 AA |
1640 | int hugepage_madvise(struct vm_area_struct *vma, |
1641 | unsigned long *vm_flags, int advice) | |
0af4e98b | 1642 | { |
8e72033f GS |
1643 | struct mm_struct *mm = vma->vm_mm; |
1644 | ||
a664b2d8 AA |
1645 | switch (advice) { |
1646 | case MADV_HUGEPAGE: | |
1647 | /* | |
1648 | * Be somewhat over-protective like KSM for now! | |
1649 | */ | |
78f11a25 | 1650 | if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) |
a664b2d8 | 1651 | return -EINVAL; |
8e72033f GS |
1652 | if (mm->def_flags & VM_NOHUGEPAGE) |
1653 | return -EINVAL; | |
a664b2d8 AA |
1654 | *vm_flags &= ~VM_NOHUGEPAGE; |
1655 | *vm_flags |= VM_HUGEPAGE; | |
60ab3244 AA |
1656 | /* |
1657 | * If the vma become good for khugepaged to scan, | |
1658 | * register it here without waiting a page fault that | |
1659 | * may not happen any time soon. | |
1660 | */ | |
1661 | if (unlikely(khugepaged_enter_vma_merge(vma))) | |
1662 | return -ENOMEM; | |
a664b2d8 AA |
1663 | break; |
1664 | case MADV_NOHUGEPAGE: | |
1665 | /* | |
1666 | * Be somewhat over-protective like KSM for now! | |
1667 | */ | |
78f11a25 | 1668 | if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) |
a664b2d8 AA |
1669 | return -EINVAL; |
1670 | *vm_flags &= ~VM_HUGEPAGE; | |
1671 | *vm_flags |= VM_NOHUGEPAGE; | |
60ab3244 AA |
1672 | /* |
1673 | * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning | |
1674 | * this vma even if we leave the mm registered in khugepaged if | |
1675 | * it got registered before VM_NOHUGEPAGE was set. | |
1676 | */ | |
a664b2d8 AA |
1677 | break; |
1678 | } | |
0af4e98b AA |
1679 | |
1680 | return 0; | |
1681 | } | |
1682 | ||
ba76149f AA |
1683 | static int __init khugepaged_slab_init(void) |
1684 | { | |
1685 | mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", | |
1686 | sizeof(struct mm_slot), | |
1687 | __alignof__(struct mm_slot), 0, NULL); | |
1688 | if (!mm_slot_cache) | |
1689 | return -ENOMEM; | |
1690 | ||
1691 | return 0; | |
1692 | } | |
1693 | ||
1694 | static void __init khugepaged_slab_free(void) | |
1695 | { | |
1696 | kmem_cache_destroy(mm_slot_cache); | |
1697 | mm_slot_cache = NULL; | |
1698 | } | |
1699 | ||
1700 | static inline struct mm_slot *alloc_mm_slot(void) | |
1701 | { | |
1702 | if (!mm_slot_cache) /* initialization failed */ | |
1703 | return NULL; | |
1704 | return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); | |
1705 | } | |
1706 | ||
1707 | static inline void free_mm_slot(struct mm_slot *mm_slot) | |
1708 | { | |
1709 | kmem_cache_free(mm_slot_cache, mm_slot); | |
1710 | } | |
1711 | ||
1712 | static int __init mm_slots_hash_init(void) | |
1713 | { | |
1714 | mm_slots_hash = kzalloc(MM_SLOTS_HASH_HEADS * sizeof(struct hlist_head), | |
1715 | GFP_KERNEL); | |
1716 | if (!mm_slots_hash) | |
1717 | return -ENOMEM; | |
1718 | return 0; | |
1719 | } | |
1720 | ||
1721 | #if 0 | |
1722 | static void __init mm_slots_hash_free(void) | |
1723 | { | |
1724 | kfree(mm_slots_hash); | |
1725 | mm_slots_hash = NULL; | |
1726 | } | |
1727 | #endif | |
1728 | ||
1729 | static struct mm_slot *get_mm_slot(struct mm_struct *mm) | |
1730 | { | |
1731 | struct mm_slot *mm_slot; | |
1732 | struct hlist_head *bucket; | |
1733 | struct hlist_node *node; | |
1734 | ||
1735 | bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) | |
1736 | % MM_SLOTS_HASH_HEADS]; | |
1737 | hlist_for_each_entry(mm_slot, node, bucket, hash) { | |
1738 | if (mm == mm_slot->mm) | |
1739 | return mm_slot; | |
1740 | } | |
1741 | return NULL; | |
1742 | } | |
1743 | ||
1744 | static void insert_to_mm_slots_hash(struct mm_struct *mm, | |
1745 | struct mm_slot *mm_slot) | |
1746 | { | |
1747 | struct hlist_head *bucket; | |
1748 | ||
1749 | bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) | |
1750 | % MM_SLOTS_HASH_HEADS]; | |
1751 | mm_slot->mm = mm; | |
1752 | hlist_add_head(&mm_slot->hash, bucket); | |
1753 | } | |
1754 | ||
1755 | static inline int khugepaged_test_exit(struct mm_struct *mm) | |
1756 | { | |
1757 | return atomic_read(&mm->mm_users) == 0; | |
1758 | } | |
1759 | ||
1760 | int __khugepaged_enter(struct mm_struct *mm) | |
1761 | { | |
1762 | struct mm_slot *mm_slot; | |
1763 | int wakeup; | |
1764 | ||
1765 | mm_slot = alloc_mm_slot(); | |
1766 | if (!mm_slot) | |
1767 | return -ENOMEM; | |
1768 | ||
1769 | /* __khugepaged_exit() must not run from under us */ | |
1770 | VM_BUG_ON(khugepaged_test_exit(mm)); | |
1771 | if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { | |
1772 | free_mm_slot(mm_slot); | |
1773 | return 0; | |
1774 | } | |
1775 | ||
1776 | spin_lock(&khugepaged_mm_lock); | |
1777 | insert_to_mm_slots_hash(mm, mm_slot); | |
1778 | /* | |
1779 | * Insert just behind the scanning cursor, to let the area settle | |
1780 | * down a little. | |
1781 | */ | |
1782 | wakeup = list_empty(&khugepaged_scan.mm_head); | |
1783 | list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); | |
1784 | spin_unlock(&khugepaged_mm_lock); | |
1785 | ||
1786 | atomic_inc(&mm->mm_count); | |
1787 | if (wakeup) | |
1788 | wake_up_interruptible(&khugepaged_wait); | |
1789 | ||
1790 | return 0; | |
1791 | } | |
1792 | ||
1793 | int khugepaged_enter_vma_merge(struct vm_area_struct *vma) | |
1794 | { | |
1795 | unsigned long hstart, hend; | |
1796 | if (!vma->anon_vma) | |
1797 | /* | |
1798 | * Not yet faulted in so we will register later in the | |
1799 | * page fault if needed. | |
1800 | */ | |
1801 | return 0; | |
78f11a25 | 1802 | if (vma->vm_ops) |
ba76149f AA |
1803 | /* khugepaged not yet working on file or special mappings */ |
1804 | return 0; | |
b3b9c293 | 1805 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); |
ba76149f AA |
1806 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
1807 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
1808 | if (hstart < hend) | |
1809 | return khugepaged_enter(vma); | |
1810 | return 0; | |
1811 | } | |
1812 | ||
1813 | void __khugepaged_exit(struct mm_struct *mm) | |
1814 | { | |
1815 | struct mm_slot *mm_slot; | |
1816 | int free = 0; | |
1817 | ||
1818 | spin_lock(&khugepaged_mm_lock); | |
1819 | mm_slot = get_mm_slot(mm); | |
1820 | if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { | |
1821 | hlist_del(&mm_slot->hash); | |
1822 | list_del(&mm_slot->mm_node); | |
1823 | free = 1; | |
1824 | } | |
d788e80a | 1825 | spin_unlock(&khugepaged_mm_lock); |
ba76149f AA |
1826 | |
1827 | if (free) { | |
ba76149f AA |
1828 | clear_bit(MMF_VM_HUGEPAGE, &mm->flags); |
1829 | free_mm_slot(mm_slot); | |
1830 | mmdrop(mm); | |
1831 | } else if (mm_slot) { | |
ba76149f AA |
1832 | /* |
1833 | * This is required to serialize against | |
1834 | * khugepaged_test_exit() (which is guaranteed to run | |
1835 | * under mmap sem read mode). Stop here (after we | |
1836 | * return all pagetables will be destroyed) until | |
1837 | * khugepaged has finished working on the pagetables | |
1838 | * under the mmap_sem. | |
1839 | */ | |
1840 | down_write(&mm->mmap_sem); | |
1841 | up_write(&mm->mmap_sem); | |
d788e80a | 1842 | } |
ba76149f AA |
1843 | } |
1844 | ||
1845 | static void release_pte_page(struct page *page) | |
1846 | { | |
1847 | /* 0 stands for page_is_file_cache(page) == false */ | |
1848 | dec_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
1849 | unlock_page(page); | |
1850 | putback_lru_page(page); | |
1851 | } | |
1852 | ||
1853 | static void release_pte_pages(pte_t *pte, pte_t *_pte) | |
1854 | { | |
1855 | while (--_pte >= pte) { | |
1856 | pte_t pteval = *_pte; | |
1857 | if (!pte_none(pteval)) | |
1858 | release_pte_page(pte_page(pteval)); | |
1859 | } | |
1860 | } | |
1861 | ||
ba76149f AA |
1862 | static int __collapse_huge_page_isolate(struct vm_area_struct *vma, |
1863 | unsigned long address, | |
1864 | pte_t *pte) | |
1865 | { | |
1866 | struct page *page; | |
1867 | pte_t *_pte; | |
344aa35c | 1868 | int referenced = 0, none = 0; |
ba76149f AA |
1869 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; |
1870 | _pte++, address += PAGE_SIZE) { | |
1871 | pte_t pteval = *_pte; | |
1872 | if (pte_none(pteval)) { | |
1873 | if (++none <= khugepaged_max_ptes_none) | |
1874 | continue; | |
344aa35c | 1875 | else |
ba76149f | 1876 | goto out; |
ba76149f | 1877 | } |
344aa35c | 1878 | if (!pte_present(pteval) || !pte_write(pteval)) |
ba76149f | 1879 | goto out; |
ba76149f | 1880 | page = vm_normal_page(vma, address, pteval); |
344aa35c | 1881 | if (unlikely(!page)) |
ba76149f | 1882 | goto out; |
344aa35c | 1883 | |
ba76149f AA |
1884 | VM_BUG_ON(PageCompound(page)); |
1885 | BUG_ON(!PageAnon(page)); | |
1886 | VM_BUG_ON(!PageSwapBacked(page)); | |
1887 | ||
1888 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
344aa35c | 1889 | if (page_count(page) != 1) |
ba76149f | 1890 | goto out; |
ba76149f AA |
1891 | /* |
1892 | * We can do it before isolate_lru_page because the | |
1893 | * page can't be freed from under us. NOTE: PG_lock | |
1894 | * is needed to serialize against split_huge_page | |
1895 | * when invoked from the VM. | |
1896 | */ | |
344aa35c | 1897 | if (!trylock_page(page)) |
ba76149f | 1898 | goto out; |
ba76149f AA |
1899 | /* |
1900 | * Isolate the page to avoid collapsing an hugepage | |
1901 | * currently in use by the VM. | |
1902 | */ | |
1903 | if (isolate_lru_page(page)) { | |
1904 | unlock_page(page); | |
ba76149f AA |
1905 | goto out; |
1906 | } | |
1907 | /* 0 stands for page_is_file_cache(page) == false */ | |
1908 | inc_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
1909 | VM_BUG_ON(!PageLocked(page)); | |
1910 | VM_BUG_ON(PageLRU(page)); | |
1911 | ||
1912 | /* If there is no mapped pte young don't collapse the page */ | |
8ee53820 AA |
1913 | if (pte_young(pteval) || PageReferenced(page) || |
1914 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
1915 | referenced = 1; |
1916 | } | |
344aa35c BL |
1917 | if (likely(referenced)) |
1918 | return 1; | |
ba76149f | 1919 | out: |
344aa35c BL |
1920 | release_pte_pages(pte, _pte); |
1921 | return 0; | |
ba76149f AA |
1922 | } |
1923 | ||
1924 | static void __collapse_huge_page_copy(pte_t *pte, struct page *page, | |
1925 | struct vm_area_struct *vma, | |
1926 | unsigned long address, | |
1927 | spinlock_t *ptl) | |
1928 | { | |
1929 | pte_t *_pte; | |
1930 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { | |
1931 | pte_t pteval = *_pte; | |
1932 | struct page *src_page; | |
1933 | ||
1934 | if (pte_none(pteval)) { | |
1935 | clear_user_highpage(page, address); | |
1936 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); | |
1937 | } else { | |
1938 | src_page = pte_page(pteval); | |
1939 | copy_user_highpage(page, src_page, address, vma); | |
1940 | VM_BUG_ON(page_mapcount(src_page) != 1); | |
ba76149f AA |
1941 | release_pte_page(src_page); |
1942 | /* | |
1943 | * ptl mostly unnecessary, but preempt has to | |
1944 | * be disabled to update the per-cpu stats | |
1945 | * inside page_remove_rmap(). | |
1946 | */ | |
1947 | spin_lock(ptl); | |
1948 | /* | |
1949 | * paravirt calls inside pte_clear here are | |
1950 | * superfluous. | |
1951 | */ | |
1952 | pte_clear(vma->vm_mm, address, _pte); | |
1953 | page_remove_rmap(src_page); | |
1954 | spin_unlock(ptl); | |
1955 | free_page_and_swap_cache(src_page); | |
1956 | } | |
1957 | ||
1958 | address += PAGE_SIZE; | |
1959 | page++; | |
1960 | } | |
1961 | } | |
1962 | ||
26234f36 | 1963 | static void khugepaged_alloc_sleep(void) |
ba76149f | 1964 | { |
26234f36 XG |
1965 | wait_event_freezable_timeout(khugepaged_wait, false, |
1966 | msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); | |
1967 | } | |
ba76149f | 1968 | |
26234f36 XG |
1969 | #ifdef CONFIG_NUMA |
1970 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
1971 | { | |
1972 | if (IS_ERR(*hpage)) { | |
1973 | if (!*wait) | |
1974 | return false; | |
1975 | ||
1976 | *wait = false; | |
e3b4126c | 1977 | *hpage = NULL; |
26234f36 XG |
1978 | khugepaged_alloc_sleep(); |
1979 | } else if (*hpage) { | |
1980 | put_page(*hpage); | |
1981 | *hpage = NULL; | |
1982 | } | |
1983 | ||
1984 | return true; | |
1985 | } | |
1986 | ||
1987 | static struct page | |
1988 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
1989 | struct vm_area_struct *vma, unsigned long address, | |
1990 | int node) | |
1991 | { | |
0bbbc0b3 | 1992 | VM_BUG_ON(*hpage); |
ce83d217 AA |
1993 | /* |
1994 | * Allocate the page while the vma is still valid and under | |
1995 | * the mmap_sem read mode so there is no memory allocation | |
1996 | * later when we take the mmap_sem in write mode. This is more | |
1997 | * friendly behavior (OTOH it may actually hide bugs) to | |
1998 | * filesystems in userland with daemons allocating memory in | |
1999 | * the userland I/O paths. Allocating memory with the | |
2000 | * mmap_sem in read mode is good idea also to allow greater | |
2001 | * scalability. | |
2002 | */ | |
26234f36 | 2003 | *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address, |
cc5d462f | 2004 | node, __GFP_OTHER_NODE); |
692e0b35 AA |
2005 | |
2006 | /* | |
2007 | * After allocating the hugepage, release the mmap_sem read lock in | |
2008 | * preparation for taking it in write mode. | |
2009 | */ | |
2010 | up_read(&mm->mmap_sem); | |
26234f36 | 2011 | if (unlikely(!*hpage)) { |
81ab4201 | 2012 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); |
ce83d217 | 2013 | *hpage = ERR_PTR(-ENOMEM); |
26234f36 | 2014 | return NULL; |
ce83d217 | 2015 | } |
26234f36 | 2016 | |
65b3c07b | 2017 | count_vm_event(THP_COLLAPSE_ALLOC); |
26234f36 XG |
2018 | return *hpage; |
2019 | } | |
2020 | #else | |
2021 | static struct page *khugepaged_alloc_hugepage(bool *wait) | |
2022 | { | |
2023 | struct page *hpage; | |
2024 | ||
2025 | do { | |
2026 | hpage = alloc_hugepage(khugepaged_defrag()); | |
2027 | if (!hpage) { | |
2028 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); | |
2029 | if (!*wait) | |
2030 | return NULL; | |
2031 | ||
2032 | *wait = false; | |
2033 | khugepaged_alloc_sleep(); | |
2034 | } else | |
2035 | count_vm_event(THP_COLLAPSE_ALLOC); | |
2036 | } while (unlikely(!hpage) && likely(khugepaged_enabled())); | |
2037 | ||
2038 | return hpage; | |
2039 | } | |
2040 | ||
2041 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
2042 | { | |
2043 | if (!*hpage) | |
2044 | *hpage = khugepaged_alloc_hugepage(wait); | |
2045 | ||
2046 | if (unlikely(!*hpage)) | |
2047 | return false; | |
2048 | ||
2049 | return true; | |
2050 | } | |
2051 | ||
2052 | static struct page | |
2053 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2054 | struct vm_area_struct *vma, unsigned long address, | |
2055 | int node) | |
2056 | { | |
2057 | up_read(&mm->mmap_sem); | |
2058 | VM_BUG_ON(!*hpage); | |
2059 | return *hpage; | |
2060 | } | |
692e0b35 AA |
2061 | #endif |
2062 | ||
fa475e51 BL |
2063 | static bool hugepage_vma_check(struct vm_area_struct *vma) |
2064 | { | |
2065 | if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || | |
2066 | (vma->vm_flags & VM_NOHUGEPAGE)) | |
2067 | return false; | |
2068 | ||
2069 | if (!vma->anon_vma || vma->vm_ops) | |
2070 | return false; | |
2071 | if (is_vma_temporary_stack(vma)) | |
2072 | return false; | |
2073 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); | |
2074 | return true; | |
2075 | } | |
2076 | ||
26234f36 XG |
2077 | static void collapse_huge_page(struct mm_struct *mm, |
2078 | unsigned long address, | |
2079 | struct page **hpage, | |
2080 | struct vm_area_struct *vma, | |
2081 | int node) | |
2082 | { | |
26234f36 XG |
2083 | pmd_t *pmd, _pmd; |
2084 | pte_t *pte; | |
2085 | pgtable_t pgtable; | |
2086 | struct page *new_page; | |
2087 | spinlock_t *ptl; | |
2088 | int isolated; | |
2089 | unsigned long hstart, hend; | |
2ec74c3e SG |
2090 | unsigned long mmun_start; /* For mmu_notifiers */ |
2091 | unsigned long mmun_end; /* For mmu_notifiers */ | |
26234f36 XG |
2092 | |
2093 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2094 | ||
2095 | /* release the mmap_sem read lock. */ | |
2096 | new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); | |
2097 | if (!new_page) | |
2098 | return; | |
2099 | ||
420256ef | 2100 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) |
ce83d217 | 2101 | return; |
ba76149f AA |
2102 | |
2103 | /* | |
2104 | * Prevent all access to pagetables with the exception of | |
2105 | * gup_fast later hanlded by the ptep_clear_flush and the VM | |
2106 | * handled by the anon_vma lock + PG_lock. | |
2107 | */ | |
2108 | down_write(&mm->mmap_sem); | |
2109 | if (unlikely(khugepaged_test_exit(mm))) | |
2110 | goto out; | |
2111 | ||
2112 | vma = find_vma(mm, address); | |
2113 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; | |
2114 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2115 | if (address < hstart || address + HPAGE_PMD_SIZE > hend) | |
2116 | goto out; | |
fa475e51 | 2117 | if (!hugepage_vma_check(vma)) |
a7d6e4ec | 2118 | goto out; |
6219049a BL |
2119 | pmd = mm_find_pmd(mm, address); |
2120 | if (!pmd) | |
ba76149f | 2121 | goto out; |
6219049a | 2122 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2123 | goto out; |
2124 | ||
ba76149f AA |
2125 | anon_vma_lock(vma->anon_vma); |
2126 | ||
2127 | pte = pte_offset_map(pmd, address); | |
2128 | ptl = pte_lockptr(mm, pmd); | |
2129 | ||
2ec74c3e SG |
2130 | mmun_start = address; |
2131 | mmun_end = address + HPAGE_PMD_SIZE; | |
2132 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
ba76149f AA |
2133 | spin_lock(&mm->page_table_lock); /* probably unnecessary */ |
2134 | /* | |
2135 | * After this gup_fast can't run anymore. This also removes | |
2136 | * any huge TLB entry from the CPU so we won't allow | |
2137 | * huge and small TLB entries for the same virtual address | |
2138 | * to avoid the risk of CPU bugs in that area. | |
2139 | */ | |
2ec74c3e | 2140 | _pmd = pmdp_clear_flush(vma, address, pmd); |
ba76149f | 2141 | spin_unlock(&mm->page_table_lock); |
2ec74c3e | 2142 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
ba76149f AA |
2143 | |
2144 | spin_lock(ptl); | |
2145 | isolated = __collapse_huge_page_isolate(vma, address, pte); | |
2146 | spin_unlock(ptl); | |
ba76149f AA |
2147 | |
2148 | if (unlikely(!isolated)) { | |
453c7192 | 2149 | pte_unmap(pte); |
ba76149f AA |
2150 | spin_lock(&mm->page_table_lock); |
2151 | BUG_ON(!pmd_none(*pmd)); | |
2152 | set_pmd_at(mm, address, pmd, _pmd); | |
2153 | spin_unlock(&mm->page_table_lock); | |
2154 | anon_vma_unlock(vma->anon_vma); | |
ce83d217 | 2155 | goto out; |
ba76149f AA |
2156 | } |
2157 | ||
2158 | /* | |
2159 | * All pages are isolated and locked so anon_vma rmap | |
2160 | * can't run anymore. | |
2161 | */ | |
2162 | anon_vma_unlock(vma->anon_vma); | |
2163 | ||
2164 | __collapse_huge_page_copy(pte, new_page, vma, address, ptl); | |
453c7192 | 2165 | pte_unmap(pte); |
ba76149f AA |
2166 | __SetPageUptodate(new_page); |
2167 | pgtable = pmd_pgtable(_pmd); | |
ba76149f | 2168 | |
b3092b3b | 2169 | _pmd = mk_huge_pmd(new_page, vma); |
ba76149f AA |
2170 | |
2171 | /* | |
2172 | * spin_lock() below is not the equivalent of smp_wmb(), so | |
2173 | * this is needed to avoid the copy_huge_page writes to become | |
2174 | * visible after the set_pmd_at() write. | |
2175 | */ | |
2176 | smp_wmb(); | |
2177 | ||
2178 | spin_lock(&mm->page_table_lock); | |
2179 | BUG_ON(!pmd_none(*pmd)); | |
2180 | page_add_new_anon_rmap(new_page, vma, address); | |
2181 | set_pmd_at(mm, address, pmd, _pmd); | |
b113da65 | 2182 | update_mmu_cache_pmd(vma, address, pmd); |
e3ebcf64 | 2183 | pgtable_trans_huge_deposit(mm, pgtable); |
ba76149f AA |
2184 | spin_unlock(&mm->page_table_lock); |
2185 | ||
2186 | *hpage = NULL; | |
420256ef | 2187 | |
ba76149f | 2188 | khugepaged_pages_collapsed++; |
ce83d217 | 2189 | out_up_write: |
ba76149f | 2190 | up_write(&mm->mmap_sem); |
0bbbc0b3 AA |
2191 | return; |
2192 | ||
ce83d217 | 2193 | out: |
678ff896 | 2194 | mem_cgroup_uncharge_page(new_page); |
ce83d217 | 2195 | goto out_up_write; |
ba76149f AA |
2196 | } |
2197 | ||
2198 | static int khugepaged_scan_pmd(struct mm_struct *mm, | |
2199 | struct vm_area_struct *vma, | |
2200 | unsigned long address, | |
2201 | struct page **hpage) | |
2202 | { | |
ba76149f AA |
2203 | pmd_t *pmd; |
2204 | pte_t *pte, *_pte; | |
2205 | int ret = 0, referenced = 0, none = 0; | |
2206 | struct page *page; | |
2207 | unsigned long _address; | |
2208 | spinlock_t *ptl; | |
5c4b4be3 | 2209 | int node = -1; |
ba76149f AA |
2210 | |
2211 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2212 | ||
6219049a BL |
2213 | pmd = mm_find_pmd(mm, address); |
2214 | if (!pmd) | |
ba76149f | 2215 | goto out; |
6219049a | 2216 | if (pmd_trans_huge(*pmd)) |
ba76149f AA |
2217 | goto out; |
2218 | ||
2219 | pte = pte_offset_map_lock(mm, pmd, address, &ptl); | |
2220 | for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; | |
2221 | _pte++, _address += PAGE_SIZE) { | |
2222 | pte_t pteval = *_pte; | |
2223 | if (pte_none(pteval)) { | |
2224 | if (++none <= khugepaged_max_ptes_none) | |
2225 | continue; | |
2226 | else | |
2227 | goto out_unmap; | |
2228 | } | |
2229 | if (!pte_present(pteval) || !pte_write(pteval)) | |
2230 | goto out_unmap; | |
2231 | page = vm_normal_page(vma, _address, pteval); | |
2232 | if (unlikely(!page)) | |
2233 | goto out_unmap; | |
5c4b4be3 AK |
2234 | /* |
2235 | * Chose the node of the first page. This could | |
2236 | * be more sophisticated and look at more pages, | |
2237 | * but isn't for now. | |
2238 | */ | |
2239 | if (node == -1) | |
2240 | node = page_to_nid(page); | |
ba76149f AA |
2241 | VM_BUG_ON(PageCompound(page)); |
2242 | if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) | |
2243 | goto out_unmap; | |
2244 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
2245 | if (page_count(page) != 1) | |
2246 | goto out_unmap; | |
8ee53820 AA |
2247 | if (pte_young(pteval) || PageReferenced(page) || |
2248 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2249 | referenced = 1; |
2250 | } | |
2251 | if (referenced) | |
2252 | ret = 1; | |
2253 | out_unmap: | |
2254 | pte_unmap_unlock(pte, ptl); | |
ce83d217 AA |
2255 | if (ret) |
2256 | /* collapse_huge_page will return with the mmap_sem released */ | |
5c4b4be3 | 2257 | collapse_huge_page(mm, address, hpage, vma, node); |
ba76149f AA |
2258 | out: |
2259 | return ret; | |
2260 | } | |
2261 | ||
2262 | static void collect_mm_slot(struct mm_slot *mm_slot) | |
2263 | { | |
2264 | struct mm_struct *mm = mm_slot->mm; | |
2265 | ||
b9980cdc | 2266 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2267 | |
2268 | if (khugepaged_test_exit(mm)) { | |
2269 | /* free mm_slot */ | |
2270 | hlist_del(&mm_slot->hash); | |
2271 | list_del(&mm_slot->mm_node); | |
2272 | ||
2273 | /* | |
2274 | * Not strictly needed because the mm exited already. | |
2275 | * | |
2276 | * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); | |
2277 | */ | |
2278 | ||
2279 | /* khugepaged_mm_lock actually not necessary for the below */ | |
2280 | free_mm_slot(mm_slot); | |
2281 | mmdrop(mm); | |
2282 | } | |
2283 | } | |
2284 | ||
2285 | static unsigned int khugepaged_scan_mm_slot(unsigned int pages, | |
2286 | struct page **hpage) | |
2f1da642 HS |
2287 | __releases(&khugepaged_mm_lock) |
2288 | __acquires(&khugepaged_mm_lock) | |
ba76149f AA |
2289 | { |
2290 | struct mm_slot *mm_slot; | |
2291 | struct mm_struct *mm; | |
2292 | struct vm_area_struct *vma; | |
2293 | int progress = 0; | |
2294 | ||
2295 | VM_BUG_ON(!pages); | |
b9980cdc | 2296 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2297 | |
2298 | if (khugepaged_scan.mm_slot) | |
2299 | mm_slot = khugepaged_scan.mm_slot; | |
2300 | else { | |
2301 | mm_slot = list_entry(khugepaged_scan.mm_head.next, | |
2302 | struct mm_slot, mm_node); | |
2303 | khugepaged_scan.address = 0; | |
2304 | khugepaged_scan.mm_slot = mm_slot; | |
2305 | } | |
2306 | spin_unlock(&khugepaged_mm_lock); | |
2307 | ||
2308 | mm = mm_slot->mm; | |
2309 | down_read(&mm->mmap_sem); | |
2310 | if (unlikely(khugepaged_test_exit(mm))) | |
2311 | vma = NULL; | |
2312 | else | |
2313 | vma = find_vma(mm, khugepaged_scan.address); | |
2314 | ||
2315 | progress++; | |
2316 | for (; vma; vma = vma->vm_next) { | |
2317 | unsigned long hstart, hend; | |
2318 | ||
2319 | cond_resched(); | |
2320 | if (unlikely(khugepaged_test_exit(mm))) { | |
2321 | progress++; | |
2322 | break; | |
2323 | } | |
fa475e51 BL |
2324 | if (!hugepage_vma_check(vma)) { |
2325 | skip: | |
ba76149f AA |
2326 | progress++; |
2327 | continue; | |
2328 | } | |
ba76149f AA |
2329 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
2330 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
a7d6e4ec AA |
2331 | if (hstart >= hend) |
2332 | goto skip; | |
2333 | if (khugepaged_scan.address > hend) | |
2334 | goto skip; | |
ba76149f AA |
2335 | if (khugepaged_scan.address < hstart) |
2336 | khugepaged_scan.address = hstart; | |
a7d6e4ec | 2337 | VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); |
ba76149f AA |
2338 | |
2339 | while (khugepaged_scan.address < hend) { | |
2340 | int ret; | |
2341 | cond_resched(); | |
2342 | if (unlikely(khugepaged_test_exit(mm))) | |
2343 | goto breakouterloop; | |
2344 | ||
2345 | VM_BUG_ON(khugepaged_scan.address < hstart || | |
2346 | khugepaged_scan.address + HPAGE_PMD_SIZE > | |
2347 | hend); | |
2348 | ret = khugepaged_scan_pmd(mm, vma, | |
2349 | khugepaged_scan.address, | |
2350 | hpage); | |
2351 | /* move to next address */ | |
2352 | khugepaged_scan.address += HPAGE_PMD_SIZE; | |
2353 | progress += HPAGE_PMD_NR; | |
2354 | if (ret) | |
2355 | /* we released mmap_sem so break loop */ | |
2356 | goto breakouterloop_mmap_sem; | |
2357 | if (progress >= pages) | |
2358 | goto breakouterloop; | |
2359 | } | |
2360 | } | |
2361 | breakouterloop: | |
2362 | up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ | |
2363 | breakouterloop_mmap_sem: | |
2364 | ||
2365 | spin_lock(&khugepaged_mm_lock); | |
a7d6e4ec | 2366 | VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); |
ba76149f AA |
2367 | /* |
2368 | * Release the current mm_slot if this mm is about to die, or | |
2369 | * if we scanned all vmas of this mm. | |
2370 | */ | |
2371 | if (khugepaged_test_exit(mm) || !vma) { | |
2372 | /* | |
2373 | * Make sure that if mm_users is reaching zero while | |
2374 | * khugepaged runs here, khugepaged_exit will find | |
2375 | * mm_slot not pointing to the exiting mm. | |
2376 | */ | |
2377 | if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { | |
2378 | khugepaged_scan.mm_slot = list_entry( | |
2379 | mm_slot->mm_node.next, | |
2380 | struct mm_slot, mm_node); | |
2381 | khugepaged_scan.address = 0; | |
2382 | } else { | |
2383 | khugepaged_scan.mm_slot = NULL; | |
2384 | khugepaged_full_scans++; | |
2385 | } | |
2386 | ||
2387 | collect_mm_slot(mm_slot); | |
2388 | } | |
2389 | ||
2390 | return progress; | |
2391 | } | |
2392 | ||
2393 | static int khugepaged_has_work(void) | |
2394 | { | |
2395 | return !list_empty(&khugepaged_scan.mm_head) && | |
2396 | khugepaged_enabled(); | |
2397 | } | |
2398 | ||
2399 | static int khugepaged_wait_event(void) | |
2400 | { | |
2401 | return !list_empty(&khugepaged_scan.mm_head) || | |
2017c0bf | 2402 | kthread_should_stop(); |
ba76149f AA |
2403 | } |
2404 | ||
d516904b | 2405 | static void khugepaged_do_scan(void) |
ba76149f | 2406 | { |
d516904b | 2407 | struct page *hpage = NULL; |
ba76149f AA |
2408 | unsigned int progress = 0, pass_through_head = 0; |
2409 | unsigned int pages = khugepaged_pages_to_scan; | |
d516904b | 2410 | bool wait = true; |
ba76149f AA |
2411 | |
2412 | barrier(); /* write khugepaged_pages_to_scan to local stack */ | |
2413 | ||
2414 | while (progress < pages) { | |
26234f36 | 2415 | if (!khugepaged_prealloc_page(&hpage, &wait)) |
d516904b | 2416 | break; |
26234f36 | 2417 | |
420256ef | 2418 | cond_resched(); |
ba76149f | 2419 | |
878aee7d AA |
2420 | if (unlikely(kthread_should_stop() || freezing(current))) |
2421 | break; | |
2422 | ||
ba76149f AA |
2423 | spin_lock(&khugepaged_mm_lock); |
2424 | if (!khugepaged_scan.mm_slot) | |
2425 | pass_through_head++; | |
2426 | if (khugepaged_has_work() && | |
2427 | pass_through_head < 2) | |
2428 | progress += khugepaged_scan_mm_slot(pages - progress, | |
d516904b | 2429 | &hpage); |
ba76149f AA |
2430 | else |
2431 | progress = pages; | |
2432 | spin_unlock(&khugepaged_mm_lock); | |
2433 | } | |
ba76149f | 2434 | |
d516904b XG |
2435 | if (!IS_ERR_OR_NULL(hpage)) |
2436 | put_page(hpage); | |
0bbbc0b3 AA |
2437 | } |
2438 | ||
2017c0bf XG |
2439 | static void khugepaged_wait_work(void) |
2440 | { | |
2441 | try_to_freeze(); | |
2442 | ||
2443 | if (khugepaged_has_work()) { | |
2444 | if (!khugepaged_scan_sleep_millisecs) | |
2445 | return; | |
2446 | ||
2447 | wait_event_freezable_timeout(khugepaged_wait, | |
2448 | kthread_should_stop(), | |
2449 | msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); | |
2450 | return; | |
2451 | } | |
2452 | ||
2453 | if (khugepaged_enabled()) | |
2454 | wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); | |
2455 | } | |
2456 | ||
ba76149f AA |
2457 | static int khugepaged(void *none) |
2458 | { | |
2459 | struct mm_slot *mm_slot; | |
2460 | ||
878aee7d | 2461 | set_freezable(); |
ba76149f AA |
2462 | set_user_nice(current, 19); |
2463 | ||
b7231789 XG |
2464 | while (!kthread_should_stop()) { |
2465 | khugepaged_do_scan(); | |
2466 | khugepaged_wait_work(); | |
2467 | } | |
ba76149f AA |
2468 | |
2469 | spin_lock(&khugepaged_mm_lock); | |
2470 | mm_slot = khugepaged_scan.mm_slot; | |
2471 | khugepaged_scan.mm_slot = NULL; | |
2472 | if (mm_slot) | |
2473 | collect_mm_slot(mm_slot); | |
2474 | spin_unlock(&khugepaged_mm_lock); | |
ba76149f AA |
2475 | return 0; |
2476 | } | |
2477 | ||
e180377f KS |
2478 | void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, |
2479 | pmd_t *pmd) | |
71e3aac0 AA |
2480 | { |
2481 | struct page *page; | |
e180377f KS |
2482 | unsigned long haddr = address & HPAGE_PMD_MASK; |
2483 | struct mm_struct *mm = vma->vm_mm; | |
2484 | ||
2485 | BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); | |
71e3aac0 AA |
2486 | |
2487 | spin_lock(&mm->page_table_lock); | |
2488 | if (unlikely(!pmd_trans_huge(*pmd))) { | |
2489 | spin_unlock(&mm->page_table_lock); | |
2490 | return; | |
2491 | } | |
2492 | page = pmd_page(*pmd); | |
2493 | VM_BUG_ON(!page_count(page)); | |
2494 | get_page(page); | |
2495 | spin_unlock(&mm->page_table_lock); | |
2496 | ||
2497 | split_huge_page(page); | |
2498 | ||
2499 | put_page(page); | |
2500 | BUG_ON(pmd_trans_huge(*pmd)); | |
2501 | } | |
94fcc585 | 2502 | |
e180377f KS |
2503 | void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address, |
2504 | pmd_t *pmd) | |
2505 | { | |
2506 | struct vm_area_struct *vma; | |
2507 | ||
2508 | vma = find_vma(mm, address); | |
2509 | BUG_ON(vma == NULL); | |
2510 | split_huge_page_pmd(vma, address, pmd); | |
2511 | } | |
2512 | ||
94fcc585 AA |
2513 | static void split_huge_page_address(struct mm_struct *mm, |
2514 | unsigned long address) | |
2515 | { | |
94fcc585 AA |
2516 | pmd_t *pmd; |
2517 | ||
2518 | VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); | |
2519 | ||
6219049a BL |
2520 | pmd = mm_find_pmd(mm, address); |
2521 | if (!pmd) | |
94fcc585 AA |
2522 | return; |
2523 | /* | |
2524 | * Caller holds the mmap_sem write mode, so a huge pmd cannot | |
2525 | * materialize from under us. | |
2526 | */ | |
e180377f | 2527 | split_huge_page_pmd_mm(mm, address, pmd); |
94fcc585 AA |
2528 | } |
2529 | ||
2530 | void __vma_adjust_trans_huge(struct vm_area_struct *vma, | |
2531 | unsigned long start, | |
2532 | unsigned long end, | |
2533 | long adjust_next) | |
2534 | { | |
2535 | /* | |
2536 | * If the new start address isn't hpage aligned and it could | |
2537 | * previously contain an hugepage: check if we need to split | |
2538 | * an huge pmd. | |
2539 | */ | |
2540 | if (start & ~HPAGE_PMD_MASK && | |
2541 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2542 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2543 | split_huge_page_address(vma->vm_mm, start); | |
2544 | ||
2545 | /* | |
2546 | * If the new end address isn't hpage aligned and it could | |
2547 | * previously contain an hugepage: check if we need to split | |
2548 | * an huge pmd. | |
2549 | */ | |
2550 | if (end & ~HPAGE_PMD_MASK && | |
2551 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2552 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2553 | split_huge_page_address(vma->vm_mm, end); | |
2554 | ||
2555 | /* | |
2556 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2557 | * vm_next->vm_start isn't page aligned and it could previously | |
2558 | * contain an hugepage: check if we need to split an huge pmd. | |
2559 | */ | |
2560 | if (adjust_next > 0) { | |
2561 | struct vm_area_struct *next = vma->vm_next; | |
2562 | unsigned long nstart = next->vm_start; | |
2563 | nstart += adjust_next << PAGE_SHIFT; | |
2564 | if (nstart & ~HPAGE_PMD_MASK && | |
2565 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2566 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
2567 | split_huge_page_address(next->vm_mm, nstart); | |
2568 | } | |
2569 | } |