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> |
4daae3b4 | 21 | #include <linux/migrate.h> |
71e3aac0 AA |
22 | #include <asm/tlb.h> |
23 | #include <asm/pgalloc.h> | |
24 | #include "internal.h" | |
25 | ||
ba76149f AA |
26 | /* |
27 | * By default transparent hugepage support is enabled for all mappings | |
28 | * and khugepaged scans all mappings. Defrag is only invoked by | |
29 | * khugepaged hugepage allocations and by page faults inside | |
30 | * MADV_HUGEPAGE regions to avoid the risk of slowing down short lived | |
31 | * allocations. | |
32 | */ | |
71e3aac0 | 33 | unsigned long transparent_hugepage_flags __read_mostly = |
13ece886 | 34 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS |
ba76149f | 35 | (1<<TRANSPARENT_HUGEPAGE_FLAG)| |
13ece886 AA |
36 | #endif |
37 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE_MADVISE | |
38 | (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)| | |
39 | #endif | |
d39d33c3 | 40 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)| |
ba76149f AA |
41 | (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); |
42 | ||
43 | /* default scan 8*512 pte (or vmas) every 30 second */ | |
44 | static unsigned int khugepaged_pages_to_scan __read_mostly = HPAGE_PMD_NR*8; | |
45 | static unsigned int khugepaged_pages_collapsed; | |
46 | static unsigned int khugepaged_full_scans; | |
47 | static unsigned int khugepaged_scan_sleep_millisecs __read_mostly = 10000; | |
48 | /* during fragmentation poll the hugepage allocator once every minute */ | |
49 | static unsigned int khugepaged_alloc_sleep_millisecs __read_mostly = 60000; | |
50 | static struct task_struct *khugepaged_thread __read_mostly; | |
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 AA |
162 | |
163 | #ifdef CONFIG_SYSFS | |
ba76149f | 164 | |
71e3aac0 AA |
165 | static ssize_t double_flag_show(struct kobject *kobj, |
166 | struct kobj_attribute *attr, char *buf, | |
167 | enum transparent_hugepage_flag enabled, | |
168 | enum transparent_hugepage_flag req_madv) | |
169 | { | |
170 | if (test_bit(enabled, &transparent_hugepage_flags)) { | |
171 | VM_BUG_ON(test_bit(req_madv, &transparent_hugepage_flags)); | |
172 | return sprintf(buf, "[always] madvise never\n"); | |
173 | } else if (test_bit(req_madv, &transparent_hugepage_flags)) | |
174 | return sprintf(buf, "always [madvise] never\n"); | |
175 | else | |
176 | return sprintf(buf, "always madvise [never]\n"); | |
177 | } | |
178 | static ssize_t double_flag_store(struct kobject *kobj, | |
179 | struct kobj_attribute *attr, | |
180 | const char *buf, size_t count, | |
181 | enum transparent_hugepage_flag enabled, | |
182 | enum transparent_hugepage_flag req_madv) | |
183 | { | |
184 | if (!memcmp("always", buf, | |
185 | min(sizeof("always")-1, count))) { | |
186 | set_bit(enabled, &transparent_hugepage_flags); | |
187 | clear_bit(req_madv, &transparent_hugepage_flags); | |
188 | } else if (!memcmp("madvise", buf, | |
189 | min(sizeof("madvise")-1, count))) { | |
190 | clear_bit(enabled, &transparent_hugepage_flags); | |
191 | set_bit(req_madv, &transparent_hugepage_flags); | |
192 | } else if (!memcmp("never", buf, | |
193 | min(sizeof("never")-1, count))) { | |
194 | clear_bit(enabled, &transparent_hugepage_flags); | |
195 | clear_bit(req_madv, &transparent_hugepage_flags); | |
196 | } else | |
197 | return -EINVAL; | |
198 | ||
199 | return count; | |
200 | } | |
201 | ||
202 | static ssize_t enabled_show(struct kobject *kobj, | |
203 | struct kobj_attribute *attr, char *buf) | |
204 | { | |
205 | return double_flag_show(kobj, attr, buf, | |
206 | TRANSPARENT_HUGEPAGE_FLAG, | |
207 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
208 | } | |
209 | static ssize_t enabled_store(struct kobject *kobj, | |
210 | struct kobj_attribute *attr, | |
211 | const char *buf, size_t count) | |
212 | { | |
ba76149f AA |
213 | ssize_t ret; |
214 | ||
215 | ret = double_flag_store(kobj, attr, buf, count, | |
216 | TRANSPARENT_HUGEPAGE_FLAG, | |
217 | TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG); | |
218 | ||
219 | if (ret > 0) { | |
911891af XG |
220 | int err; |
221 | ||
222 | mutex_lock(&khugepaged_mutex); | |
223 | err = start_khugepaged(); | |
224 | mutex_unlock(&khugepaged_mutex); | |
225 | ||
ba76149f AA |
226 | if (err) |
227 | ret = err; | |
228 | } | |
229 | ||
230 | return ret; | |
71e3aac0 AA |
231 | } |
232 | static struct kobj_attribute enabled_attr = | |
233 | __ATTR(enabled, 0644, enabled_show, enabled_store); | |
234 | ||
235 | static ssize_t single_flag_show(struct kobject *kobj, | |
236 | struct kobj_attribute *attr, char *buf, | |
237 | enum transparent_hugepage_flag flag) | |
238 | { | |
e27e6151 BH |
239 | return sprintf(buf, "%d\n", |
240 | !!test_bit(flag, &transparent_hugepage_flags)); | |
71e3aac0 | 241 | } |
e27e6151 | 242 | |
71e3aac0 AA |
243 | static ssize_t single_flag_store(struct kobject *kobj, |
244 | struct kobj_attribute *attr, | |
245 | const char *buf, size_t count, | |
246 | enum transparent_hugepage_flag flag) | |
247 | { | |
e27e6151 BH |
248 | unsigned long value; |
249 | int ret; | |
250 | ||
251 | ret = kstrtoul(buf, 10, &value); | |
252 | if (ret < 0) | |
253 | return ret; | |
254 | if (value > 1) | |
255 | return -EINVAL; | |
256 | ||
257 | if (value) | |
71e3aac0 | 258 | set_bit(flag, &transparent_hugepage_flags); |
e27e6151 | 259 | else |
71e3aac0 | 260 | clear_bit(flag, &transparent_hugepage_flags); |
71e3aac0 AA |
261 | |
262 | return count; | |
263 | } | |
264 | ||
265 | /* | |
266 | * Currently defrag only disables __GFP_NOWAIT for allocation. A blind | |
267 | * __GFP_REPEAT is too aggressive, it's never worth swapping tons of | |
268 | * memory just to allocate one more hugepage. | |
269 | */ | |
270 | static ssize_t defrag_show(struct kobject *kobj, | |
271 | struct kobj_attribute *attr, char *buf) | |
272 | { | |
273 | return double_flag_show(kobj, attr, buf, | |
274 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
275 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
276 | } | |
277 | static ssize_t defrag_store(struct kobject *kobj, | |
278 | struct kobj_attribute *attr, | |
279 | const char *buf, size_t count) | |
280 | { | |
281 | return double_flag_store(kobj, attr, buf, count, | |
282 | TRANSPARENT_HUGEPAGE_DEFRAG_FLAG, | |
283 | TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG); | |
284 | } | |
285 | static struct kobj_attribute defrag_attr = | |
286 | __ATTR(defrag, 0644, defrag_show, defrag_store); | |
287 | ||
288 | #ifdef CONFIG_DEBUG_VM | |
289 | static ssize_t debug_cow_show(struct kobject *kobj, | |
290 | struct kobj_attribute *attr, char *buf) | |
291 | { | |
292 | return single_flag_show(kobj, attr, buf, | |
293 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
294 | } | |
295 | static ssize_t debug_cow_store(struct kobject *kobj, | |
296 | struct kobj_attribute *attr, | |
297 | const char *buf, size_t count) | |
298 | { | |
299 | return single_flag_store(kobj, attr, buf, count, | |
300 | TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG); | |
301 | } | |
302 | static struct kobj_attribute debug_cow_attr = | |
303 | __ATTR(debug_cow, 0644, debug_cow_show, debug_cow_store); | |
304 | #endif /* CONFIG_DEBUG_VM */ | |
305 | ||
306 | static struct attribute *hugepage_attr[] = { | |
307 | &enabled_attr.attr, | |
308 | &defrag_attr.attr, | |
309 | #ifdef CONFIG_DEBUG_VM | |
310 | &debug_cow_attr.attr, | |
311 | #endif | |
312 | NULL, | |
313 | }; | |
314 | ||
315 | static struct attribute_group hugepage_attr_group = { | |
316 | .attrs = hugepage_attr, | |
ba76149f AA |
317 | }; |
318 | ||
319 | static ssize_t scan_sleep_millisecs_show(struct kobject *kobj, | |
320 | struct kobj_attribute *attr, | |
321 | char *buf) | |
322 | { | |
323 | return sprintf(buf, "%u\n", khugepaged_scan_sleep_millisecs); | |
324 | } | |
325 | ||
326 | static ssize_t scan_sleep_millisecs_store(struct kobject *kobj, | |
327 | struct kobj_attribute *attr, | |
328 | const char *buf, size_t count) | |
329 | { | |
330 | unsigned long msecs; | |
331 | int err; | |
332 | ||
333 | err = strict_strtoul(buf, 10, &msecs); | |
334 | if (err || msecs > UINT_MAX) | |
335 | return -EINVAL; | |
336 | ||
337 | khugepaged_scan_sleep_millisecs = msecs; | |
338 | wake_up_interruptible(&khugepaged_wait); | |
339 | ||
340 | return count; | |
341 | } | |
342 | static struct kobj_attribute scan_sleep_millisecs_attr = | |
343 | __ATTR(scan_sleep_millisecs, 0644, scan_sleep_millisecs_show, | |
344 | scan_sleep_millisecs_store); | |
345 | ||
346 | static ssize_t alloc_sleep_millisecs_show(struct kobject *kobj, | |
347 | struct kobj_attribute *attr, | |
348 | char *buf) | |
349 | { | |
350 | return sprintf(buf, "%u\n", khugepaged_alloc_sleep_millisecs); | |
351 | } | |
352 | ||
353 | static ssize_t alloc_sleep_millisecs_store(struct kobject *kobj, | |
354 | struct kobj_attribute *attr, | |
355 | const char *buf, size_t count) | |
356 | { | |
357 | unsigned long msecs; | |
358 | int err; | |
359 | ||
360 | err = strict_strtoul(buf, 10, &msecs); | |
361 | if (err || msecs > UINT_MAX) | |
362 | return -EINVAL; | |
363 | ||
364 | khugepaged_alloc_sleep_millisecs = msecs; | |
365 | wake_up_interruptible(&khugepaged_wait); | |
366 | ||
367 | return count; | |
368 | } | |
369 | static struct kobj_attribute alloc_sleep_millisecs_attr = | |
370 | __ATTR(alloc_sleep_millisecs, 0644, alloc_sleep_millisecs_show, | |
371 | alloc_sleep_millisecs_store); | |
372 | ||
373 | static ssize_t pages_to_scan_show(struct kobject *kobj, | |
374 | struct kobj_attribute *attr, | |
375 | char *buf) | |
376 | { | |
377 | return sprintf(buf, "%u\n", khugepaged_pages_to_scan); | |
378 | } | |
379 | static ssize_t pages_to_scan_store(struct kobject *kobj, | |
380 | struct kobj_attribute *attr, | |
381 | const char *buf, size_t count) | |
382 | { | |
383 | int err; | |
384 | unsigned long pages; | |
385 | ||
386 | err = strict_strtoul(buf, 10, &pages); | |
387 | if (err || !pages || pages > UINT_MAX) | |
388 | return -EINVAL; | |
389 | ||
390 | khugepaged_pages_to_scan = pages; | |
391 | ||
392 | return count; | |
393 | } | |
394 | static struct kobj_attribute pages_to_scan_attr = | |
395 | __ATTR(pages_to_scan, 0644, pages_to_scan_show, | |
396 | pages_to_scan_store); | |
397 | ||
398 | static ssize_t pages_collapsed_show(struct kobject *kobj, | |
399 | struct kobj_attribute *attr, | |
400 | char *buf) | |
401 | { | |
402 | return sprintf(buf, "%u\n", khugepaged_pages_collapsed); | |
403 | } | |
404 | static struct kobj_attribute pages_collapsed_attr = | |
405 | __ATTR_RO(pages_collapsed); | |
406 | ||
407 | static ssize_t full_scans_show(struct kobject *kobj, | |
408 | struct kobj_attribute *attr, | |
409 | char *buf) | |
410 | { | |
411 | return sprintf(buf, "%u\n", khugepaged_full_scans); | |
412 | } | |
413 | static struct kobj_attribute full_scans_attr = | |
414 | __ATTR_RO(full_scans); | |
415 | ||
416 | static ssize_t khugepaged_defrag_show(struct kobject *kobj, | |
417 | struct kobj_attribute *attr, char *buf) | |
418 | { | |
419 | return single_flag_show(kobj, attr, buf, | |
420 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
421 | } | |
422 | static ssize_t khugepaged_defrag_store(struct kobject *kobj, | |
423 | struct kobj_attribute *attr, | |
424 | const char *buf, size_t count) | |
425 | { | |
426 | return single_flag_store(kobj, attr, buf, count, | |
427 | TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG); | |
428 | } | |
429 | static struct kobj_attribute khugepaged_defrag_attr = | |
430 | __ATTR(defrag, 0644, khugepaged_defrag_show, | |
431 | khugepaged_defrag_store); | |
432 | ||
433 | /* | |
434 | * max_ptes_none controls if khugepaged should collapse hugepages over | |
435 | * any unmapped ptes in turn potentially increasing the memory | |
436 | * footprint of the vmas. When max_ptes_none is 0 khugepaged will not | |
437 | * reduce the available free memory in the system as it | |
438 | * runs. Increasing max_ptes_none will instead potentially reduce the | |
439 | * free memory in the system during the khugepaged scan. | |
440 | */ | |
441 | static ssize_t khugepaged_max_ptes_none_show(struct kobject *kobj, | |
442 | struct kobj_attribute *attr, | |
443 | char *buf) | |
444 | { | |
445 | return sprintf(buf, "%u\n", khugepaged_max_ptes_none); | |
446 | } | |
447 | static ssize_t khugepaged_max_ptes_none_store(struct kobject *kobj, | |
448 | struct kobj_attribute *attr, | |
449 | const char *buf, size_t count) | |
450 | { | |
451 | int err; | |
452 | unsigned long max_ptes_none; | |
453 | ||
454 | err = strict_strtoul(buf, 10, &max_ptes_none); | |
455 | if (err || max_ptes_none > HPAGE_PMD_NR-1) | |
456 | return -EINVAL; | |
457 | ||
458 | khugepaged_max_ptes_none = max_ptes_none; | |
459 | ||
460 | return count; | |
461 | } | |
462 | static struct kobj_attribute khugepaged_max_ptes_none_attr = | |
463 | __ATTR(max_ptes_none, 0644, khugepaged_max_ptes_none_show, | |
464 | khugepaged_max_ptes_none_store); | |
465 | ||
466 | static struct attribute *khugepaged_attr[] = { | |
467 | &khugepaged_defrag_attr.attr, | |
468 | &khugepaged_max_ptes_none_attr.attr, | |
469 | &pages_to_scan_attr.attr, | |
470 | &pages_collapsed_attr.attr, | |
471 | &full_scans_attr.attr, | |
472 | &scan_sleep_millisecs_attr.attr, | |
473 | &alloc_sleep_millisecs_attr.attr, | |
474 | NULL, | |
475 | }; | |
476 | ||
477 | static struct attribute_group khugepaged_attr_group = { | |
478 | .attrs = khugepaged_attr, | |
479 | .name = "khugepaged", | |
71e3aac0 | 480 | }; |
71e3aac0 | 481 | |
569e5590 | 482 | static int __init hugepage_init_sysfs(struct kobject **hugepage_kobj) |
71e3aac0 | 483 | { |
71e3aac0 AA |
484 | int err; |
485 | ||
569e5590 SL |
486 | *hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj); |
487 | if (unlikely(!*hugepage_kobj)) { | |
ba76149f | 488 | printk(KERN_ERR "hugepage: failed kobject create\n"); |
569e5590 | 489 | return -ENOMEM; |
ba76149f AA |
490 | } |
491 | ||
569e5590 | 492 | err = sysfs_create_group(*hugepage_kobj, &hugepage_attr_group); |
ba76149f AA |
493 | if (err) { |
494 | printk(KERN_ERR "hugepage: failed register hugeage group\n"); | |
569e5590 | 495 | goto delete_obj; |
ba76149f AA |
496 | } |
497 | ||
569e5590 | 498 | err = sysfs_create_group(*hugepage_kobj, &khugepaged_attr_group); |
ba76149f AA |
499 | if (err) { |
500 | printk(KERN_ERR "hugepage: failed register hugeage group\n"); | |
569e5590 | 501 | goto remove_hp_group; |
ba76149f | 502 | } |
569e5590 SL |
503 | |
504 | return 0; | |
505 | ||
506 | remove_hp_group: | |
507 | sysfs_remove_group(*hugepage_kobj, &hugepage_attr_group); | |
508 | delete_obj: | |
509 | kobject_put(*hugepage_kobj); | |
510 | return err; | |
511 | } | |
512 | ||
513 | static void __init hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
514 | { | |
515 | sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group); | |
516 | sysfs_remove_group(hugepage_kobj, &hugepage_attr_group); | |
517 | kobject_put(hugepage_kobj); | |
518 | } | |
519 | #else | |
520 | static inline int hugepage_init_sysfs(struct kobject **hugepage_kobj) | |
521 | { | |
522 | return 0; | |
523 | } | |
524 | ||
525 | static inline void hugepage_exit_sysfs(struct kobject *hugepage_kobj) | |
526 | { | |
527 | } | |
528 | #endif /* CONFIG_SYSFS */ | |
529 | ||
530 | static int __init hugepage_init(void) | |
531 | { | |
532 | int err; | |
533 | struct kobject *hugepage_kobj; | |
534 | ||
535 | if (!has_transparent_hugepage()) { | |
536 | transparent_hugepage_flags = 0; | |
537 | return -EINVAL; | |
538 | } | |
539 | ||
540 | err = hugepage_init_sysfs(&hugepage_kobj); | |
541 | if (err) | |
542 | return err; | |
ba76149f AA |
543 | |
544 | err = khugepaged_slab_init(); | |
545 | if (err) | |
546 | goto out; | |
547 | ||
548 | err = mm_slots_hash_init(); | |
549 | if (err) { | |
550 | khugepaged_slab_free(); | |
551 | goto out; | |
552 | } | |
553 | ||
97562cd2 RR |
554 | /* |
555 | * By default disable transparent hugepages on smaller systems, | |
556 | * where the extra memory used could hurt more than TLB overhead | |
557 | * is likely to save. The admin can still enable it through /sys. | |
558 | */ | |
559 | if (totalram_pages < (512 << (20 - PAGE_SHIFT))) | |
560 | transparent_hugepage_flags = 0; | |
561 | ||
ba76149f AA |
562 | start_khugepaged(); |
563 | ||
569e5590 | 564 | return 0; |
ba76149f | 565 | out: |
569e5590 | 566 | hugepage_exit_sysfs(hugepage_kobj); |
ba76149f | 567 | return err; |
71e3aac0 AA |
568 | } |
569 | module_init(hugepage_init) | |
570 | ||
571 | static int __init setup_transparent_hugepage(char *str) | |
572 | { | |
573 | int ret = 0; | |
574 | if (!str) | |
575 | goto out; | |
576 | if (!strcmp(str, "always")) { | |
577 | set_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
578 | &transparent_hugepage_flags); | |
579 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
580 | &transparent_hugepage_flags); | |
581 | ret = 1; | |
582 | } else if (!strcmp(str, "madvise")) { | |
583 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
584 | &transparent_hugepage_flags); | |
585 | set_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
586 | &transparent_hugepage_flags); | |
587 | ret = 1; | |
588 | } else if (!strcmp(str, "never")) { | |
589 | clear_bit(TRANSPARENT_HUGEPAGE_FLAG, | |
590 | &transparent_hugepage_flags); | |
591 | clear_bit(TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, | |
592 | &transparent_hugepage_flags); | |
593 | ret = 1; | |
594 | } | |
595 | out: | |
596 | if (!ret) | |
597 | printk(KERN_WARNING | |
598 | "transparent_hugepage= cannot parse, ignored\n"); | |
599 | return ret; | |
600 | } | |
601 | __setup("transparent_hugepage=", setup_transparent_hugepage); | |
602 | ||
b32967ff | 603 | pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) |
71e3aac0 AA |
604 | { |
605 | if (likely(vma->vm_flags & VM_WRITE)) | |
606 | pmd = pmd_mkwrite(pmd); | |
607 | return pmd; | |
608 | } | |
609 | ||
610 | static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, | |
611 | struct vm_area_struct *vma, | |
612 | unsigned long haddr, pmd_t *pmd, | |
613 | struct page *page) | |
614 | { | |
71e3aac0 AA |
615 | pgtable_t pgtable; |
616 | ||
617 | VM_BUG_ON(!PageCompound(page)); | |
618 | pgtable = pte_alloc_one(mm, haddr); | |
edad9d2c | 619 | if (unlikely(!pgtable)) |
71e3aac0 | 620 | return VM_FAULT_OOM; |
71e3aac0 AA |
621 | |
622 | clear_huge_page(page, haddr, HPAGE_PMD_NR); | |
623 | __SetPageUptodate(page); | |
624 | ||
625 | spin_lock(&mm->page_table_lock); | |
626 | if (unlikely(!pmd_none(*pmd))) { | |
627 | spin_unlock(&mm->page_table_lock); | |
b9bbfbe3 | 628 | mem_cgroup_uncharge_page(page); |
71e3aac0 AA |
629 | put_page(page); |
630 | pte_free(mm, pgtable); | |
631 | } else { | |
632 | pmd_t entry; | |
633 | entry = mk_pmd(page, vma->vm_page_prot); | |
634 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
635 | entry = pmd_mkhuge(entry); | |
636 | /* | |
637 | * The spinlocking to take the lru_lock inside | |
638 | * page_add_new_anon_rmap() acts as a full memory | |
639 | * barrier to be sure clear_huge_page writes become | |
640 | * visible after the set_pmd_at() write. | |
641 | */ | |
642 | page_add_new_anon_rmap(page, vma, haddr); | |
643 | set_pmd_at(mm, haddr, pmd, entry); | |
e3ebcf64 | 644 | pgtable_trans_huge_deposit(mm, pgtable); |
71e3aac0 | 645 | add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); |
1c641e84 | 646 | mm->nr_ptes++; |
71e3aac0 AA |
647 | spin_unlock(&mm->page_table_lock); |
648 | } | |
649 | ||
aa2e878e | 650 | return 0; |
71e3aac0 AA |
651 | } |
652 | ||
cc5d462f | 653 | static inline gfp_t alloc_hugepage_gfpmask(int defrag, gfp_t extra_gfp) |
0bbbc0b3 | 654 | { |
cc5d462f | 655 | return (GFP_TRANSHUGE & ~(defrag ? 0 : __GFP_WAIT)) | extra_gfp; |
0bbbc0b3 AA |
656 | } |
657 | ||
658 | static inline struct page *alloc_hugepage_vma(int defrag, | |
659 | struct vm_area_struct *vma, | |
cc5d462f AK |
660 | unsigned long haddr, int nd, |
661 | gfp_t extra_gfp) | |
0bbbc0b3 | 662 | { |
cc5d462f | 663 | return alloc_pages_vma(alloc_hugepage_gfpmask(defrag, extra_gfp), |
5c4b4be3 | 664 | HPAGE_PMD_ORDER, vma, haddr, nd); |
0bbbc0b3 AA |
665 | } |
666 | ||
667 | #ifndef CONFIG_NUMA | |
71e3aac0 AA |
668 | static inline struct page *alloc_hugepage(int defrag) |
669 | { | |
cc5d462f | 670 | return alloc_pages(alloc_hugepage_gfpmask(defrag, 0), |
71e3aac0 AA |
671 | HPAGE_PMD_ORDER); |
672 | } | |
0bbbc0b3 | 673 | #endif |
71e3aac0 AA |
674 | |
675 | int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
676 | unsigned long address, pmd_t *pmd, | |
677 | unsigned int flags) | |
678 | { | |
679 | struct page *page; | |
680 | unsigned long haddr = address & HPAGE_PMD_MASK; | |
681 | pte_t *pte; | |
682 | ||
683 | if (haddr >= vma->vm_start && haddr + HPAGE_PMD_SIZE <= vma->vm_end) { | |
684 | if (unlikely(anon_vma_prepare(vma))) | |
685 | return VM_FAULT_OOM; | |
ba76149f AA |
686 | if (unlikely(khugepaged_enter(vma))) |
687 | return VM_FAULT_OOM; | |
0bbbc0b3 | 688 | page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 689 | vma, haddr, numa_node_id(), 0); |
81ab4201 AK |
690 | if (unlikely(!page)) { |
691 | count_vm_event(THP_FAULT_FALLBACK); | |
71e3aac0 | 692 | goto out; |
81ab4201 AK |
693 | } |
694 | count_vm_event(THP_FAULT_ALLOC); | |
b9bbfbe3 AA |
695 | if (unlikely(mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))) { |
696 | put_page(page); | |
697 | goto out; | |
698 | } | |
edad9d2c DR |
699 | if (unlikely(__do_huge_pmd_anonymous_page(mm, vma, haddr, pmd, |
700 | page))) { | |
701 | mem_cgroup_uncharge_page(page); | |
702 | put_page(page); | |
703 | goto out; | |
704 | } | |
71e3aac0 | 705 | |
edad9d2c | 706 | return 0; |
71e3aac0 AA |
707 | } |
708 | out: | |
709 | /* | |
710 | * Use __pte_alloc instead of pte_alloc_map, because we can't | |
711 | * run pte_offset_map on the pmd, if an huge pmd could | |
712 | * materialize from under us from a different thread. | |
713 | */ | |
4fd01770 MG |
714 | if (unlikely(pmd_none(*pmd)) && |
715 | unlikely(__pte_alloc(mm, vma, pmd, address))) | |
71e3aac0 AA |
716 | return VM_FAULT_OOM; |
717 | /* if an huge pmd materialized from under us just retry later */ | |
718 | if (unlikely(pmd_trans_huge(*pmd))) | |
719 | return 0; | |
720 | /* | |
721 | * A regular pmd is established and it can't morph into a huge pmd | |
722 | * from under us anymore at this point because we hold the mmap_sem | |
723 | * read mode and khugepaged takes it in write mode. So now it's | |
724 | * safe to run pte_offset_map(). | |
725 | */ | |
726 | pte = pte_offset_map(pmd, address); | |
727 | return handle_pte_fault(mm, vma, address, pte, pmd, flags); | |
728 | } | |
729 | ||
730 | int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
731 | pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr, | |
732 | struct vm_area_struct *vma) | |
733 | { | |
734 | struct page *src_page; | |
735 | pmd_t pmd; | |
736 | pgtable_t pgtable; | |
737 | int ret; | |
738 | ||
739 | ret = -ENOMEM; | |
740 | pgtable = pte_alloc_one(dst_mm, addr); | |
741 | if (unlikely(!pgtable)) | |
742 | goto out; | |
743 | ||
744 | spin_lock(&dst_mm->page_table_lock); | |
745 | spin_lock_nested(&src_mm->page_table_lock, SINGLE_DEPTH_NESTING); | |
746 | ||
747 | ret = -EAGAIN; | |
748 | pmd = *src_pmd; | |
749 | if (unlikely(!pmd_trans_huge(pmd))) { | |
750 | pte_free(dst_mm, pgtable); | |
751 | goto out_unlock; | |
752 | } | |
753 | if (unlikely(pmd_trans_splitting(pmd))) { | |
754 | /* split huge page running from under us */ | |
755 | spin_unlock(&src_mm->page_table_lock); | |
756 | spin_unlock(&dst_mm->page_table_lock); | |
757 | pte_free(dst_mm, pgtable); | |
758 | ||
759 | wait_split_huge_page(vma->anon_vma, src_pmd); /* src_vma */ | |
760 | goto out; | |
761 | } | |
762 | src_page = pmd_page(pmd); | |
763 | VM_BUG_ON(!PageHead(src_page)); | |
764 | get_page(src_page); | |
765 | page_dup_rmap(src_page); | |
766 | add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); | |
767 | ||
768 | pmdp_set_wrprotect(src_mm, addr, src_pmd); | |
769 | pmd = pmd_mkold(pmd_wrprotect(pmd)); | |
770 | set_pmd_at(dst_mm, addr, dst_pmd, pmd); | |
e3ebcf64 | 771 | pgtable_trans_huge_deposit(dst_mm, pgtable); |
1c641e84 | 772 | dst_mm->nr_ptes++; |
71e3aac0 AA |
773 | |
774 | ret = 0; | |
775 | out_unlock: | |
776 | spin_unlock(&src_mm->page_table_lock); | |
777 | spin_unlock(&dst_mm->page_table_lock); | |
778 | out: | |
779 | return ret; | |
780 | } | |
781 | ||
71e3aac0 AA |
782 | static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, |
783 | struct vm_area_struct *vma, | |
784 | unsigned long address, | |
785 | pmd_t *pmd, pmd_t orig_pmd, | |
786 | struct page *page, | |
787 | unsigned long haddr) | |
788 | { | |
789 | pgtable_t pgtable; | |
790 | pmd_t _pmd; | |
791 | int ret = 0, i; | |
792 | struct page **pages; | |
2ec74c3e SG |
793 | unsigned long mmun_start; /* For mmu_notifiers */ |
794 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
795 | |
796 | pages = kmalloc(sizeof(struct page *) * HPAGE_PMD_NR, | |
797 | GFP_KERNEL); | |
798 | if (unlikely(!pages)) { | |
799 | ret |= VM_FAULT_OOM; | |
800 | goto out; | |
801 | } | |
802 | ||
803 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
cc5d462f AK |
804 | pages[i] = alloc_page_vma_node(GFP_HIGHUSER_MOVABLE | |
805 | __GFP_OTHER_NODE, | |
19ee151e | 806 | vma, address, page_to_nid(page)); |
b9bbfbe3 AA |
807 | if (unlikely(!pages[i] || |
808 | mem_cgroup_newpage_charge(pages[i], mm, | |
809 | GFP_KERNEL))) { | |
810 | if (pages[i]) | |
71e3aac0 | 811 | put_page(pages[i]); |
b9bbfbe3 AA |
812 | mem_cgroup_uncharge_start(); |
813 | while (--i >= 0) { | |
814 | mem_cgroup_uncharge_page(pages[i]); | |
815 | put_page(pages[i]); | |
816 | } | |
817 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
818 | kfree(pages); |
819 | ret |= VM_FAULT_OOM; | |
820 | goto out; | |
821 | } | |
822 | } | |
823 | ||
824 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
825 | copy_user_highpage(pages[i], page + i, | |
0089e485 | 826 | haddr + PAGE_SIZE * i, vma); |
71e3aac0 AA |
827 | __SetPageUptodate(pages[i]); |
828 | cond_resched(); | |
829 | } | |
830 | ||
2ec74c3e SG |
831 | mmun_start = haddr; |
832 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
833 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
834 | ||
71e3aac0 AA |
835 | spin_lock(&mm->page_table_lock); |
836 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
837 | goto out_free_pages; | |
838 | VM_BUG_ON(!PageHead(page)); | |
839 | ||
2ec74c3e | 840 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
841 | /* leave pmd empty until pte is filled */ |
842 | ||
e3ebcf64 | 843 | pgtable = pgtable_trans_huge_withdraw(mm); |
71e3aac0 AA |
844 | pmd_populate(mm, &_pmd, pgtable); |
845 | ||
846 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
847 | pte_t *pte, entry; | |
848 | entry = mk_pte(pages[i], vma->vm_page_prot); | |
849 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
850 | page_add_new_anon_rmap(pages[i], vma, haddr); | |
851 | pte = pte_offset_map(&_pmd, haddr); | |
852 | VM_BUG_ON(!pte_none(*pte)); | |
853 | set_pte_at(mm, haddr, pte, entry); | |
854 | pte_unmap(pte); | |
855 | } | |
856 | kfree(pages); | |
857 | ||
71e3aac0 AA |
858 | smp_wmb(); /* make pte visible before pmd */ |
859 | pmd_populate(mm, pmd, pgtable); | |
860 | page_remove_rmap(page); | |
861 | spin_unlock(&mm->page_table_lock); | |
862 | ||
2ec74c3e SG |
863 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
864 | ||
71e3aac0 AA |
865 | ret |= VM_FAULT_WRITE; |
866 | put_page(page); | |
867 | ||
868 | out: | |
869 | return ret; | |
870 | ||
871 | out_free_pages: | |
872 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 873 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
b9bbfbe3 AA |
874 | mem_cgroup_uncharge_start(); |
875 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
876 | mem_cgroup_uncharge_page(pages[i]); | |
71e3aac0 | 877 | put_page(pages[i]); |
b9bbfbe3 AA |
878 | } |
879 | mem_cgroup_uncharge_end(); | |
71e3aac0 AA |
880 | kfree(pages); |
881 | goto out; | |
882 | } | |
883 | ||
884 | int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
885 | unsigned long address, pmd_t *pmd, pmd_t orig_pmd) | |
886 | { | |
887 | int ret = 0; | |
888 | struct page *page, *new_page; | |
889 | unsigned long haddr; | |
2ec74c3e SG |
890 | unsigned long mmun_start; /* For mmu_notifiers */ |
891 | unsigned long mmun_end; /* For mmu_notifiers */ | |
71e3aac0 AA |
892 | |
893 | VM_BUG_ON(!vma->anon_vma); | |
894 | spin_lock(&mm->page_table_lock); | |
895 | if (unlikely(!pmd_same(*pmd, orig_pmd))) | |
896 | goto out_unlock; | |
897 | ||
898 | page = pmd_page(orig_pmd); | |
899 | VM_BUG_ON(!PageCompound(page) || !PageHead(page)); | |
900 | haddr = address & HPAGE_PMD_MASK; | |
901 | if (page_mapcount(page) == 1) { | |
902 | pmd_t entry; | |
903 | entry = pmd_mkyoung(orig_pmd); | |
904 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
905 | if (pmdp_set_access_flags(vma, haddr, pmd, entry, 1)) | |
b113da65 | 906 | update_mmu_cache_pmd(vma, address, pmd); |
71e3aac0 AA |
907 | ret |= VM_FAULT_WRITE; |
908 | goto out_unlock; | |
909 | } | |
910 | get_page(page); | |
911 | spin_unlock(&mm->page_table_lock); | |
912 | ||
913 | if (transparent_hugepage_enabled(vma) && | |
914 | !transparent_hugepage_debug_cow()) | |
0bbbc0b3 | 915 | new_page = alloc_hugepage_vma(transparent_hugepage_defrag(vma), |
cc5d462f | 916 | vma, haddr, numa_node_id(), 0); |
71e3aac0 AA |
917 | else |
918 | new_page = NULL; | |
919 | ||
920 | if (unlikely(!new_page)) { | |
81ab4201 | 921 | count_vm_event(THP_FAULT_FALLBACK); |
71e3aac0 AA |
922 | ret = do_huge_pmd_wp_page_fallback(mm, vma, address, |
923 | pmd, orig_pmd, page, haddr); | |
1f1d06c3 DR |
924 | if (ret & VM_FAULT_OOM) |
925 | split_huge_page(page); | |
71e3aac0 AA |
926 | put_page(page); |
927 | goto out; | |
928 | } | |
81ab4201 | 929 | count_vm_event(THP_FAULT_ALLOC); |
71e3aac0 | 930 | |
b9bbfbe3 AA |
931 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) { |
932 | put_page(new_page); | |
1f1d06c3 | 933 | split_huge_page(page); |
b9bbfbe3 AA |
934 | put_page(page); |
935 | ret |= VM_FAULT_OOM; | |
936 | goto out; | |
937 | } | |
938 | ||
71e3aac0 AA |
939 | copy_user_huge_page(new_page, page, haddr, vma, HPAGE_PMD_NR); |
940 | __SetPageUptodate(new_page); | |
941 | ||
2ec74c3e SG |
942 | mmun_start = haddr; |
943 | mmun_end = haddr + HPAGE_PMD_SIZE; | |
944 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
945 | ||
71e3aac0 AA |
946 | spin_lock(&mm->page_table_lock); |
947 | put_page(page); | |
b9bbfbe3 | 948 | if (unlikely(!pmd_same(*pmd, orig_pmd))) { |
6f60b69d | 949 | spin_unlock(&mm->page_table_lock); |
b9bbfbe3 | 950 | mem_cgroup_uncharge_page(new_page); |
71e3aac0 | 951 | put_page(new_page); |
2ec74c3e | 952 | goto out_mn; |
b9bbfbe3 | 953 | } else { |
71e3aac0 AA |
954 | pmd_t entry; |
955 | VM_BUG_ON(!PageHead(page)); | |
956 | entry = mk_pmd(new_page, vma->vm_page_prot); | |
957 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
958 | entry = pmd_mkhuge(entry); | |
2ec74c3e | 959 | pmdp_clear_flush(vma, haddr, pmd); |
71e3aac0 AA |
960 | page_add_new_anon_rmap(new_page, vma, haddr); |
961 | set_pmd_at(mm, haddr, pmd, entry); | |
b113da65 | 962 | update_mmu_cache_pmd(vma, address, pmd); |
71e3aac0 AA |
963 | page_remove_rmap(page); |
964 | put_page(page); | |
965 | ret |= VM_FAULT_WRITE; | |
966 | } | |
71e3aac0 | 967 | spin_unlock(&mm->page_table_lock); |
2ec74c3e SG |
968 | out_mn: |
969 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); | |
71e3aac0 AA |
970 | out: |
971 | return ret; | |
2ec74c3e SG |
972 | out_unlock: |
973 | spin_unlock(&mm->page_table_lock); | |
974 | return ret; | |
71e3aac0 AA |
975 | } |
976 | ||
b676b293 | 977 | struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, |
71e3aac0 AA |
978 | unsigned long addr, |
979 | pmd_t *pmd, | |
980 | unsigned int flags) | |
981 | { | |
b676b293 | 982 | struct mm_struct *mm = vma->vm_mm; |
71e3aac0 AA |
983 | struct page *page = NULL; |
984 | ||
985 | assert_spin_locked(&mm->page_table_lock); | |
986 | ||
987 | if (flags & FOLL_WRITE && !pmd_write(*pmd)) | |
988 | goto out; | |
989 | ||
990 | page = pmd_page(*pmd); | |
991 | VM_BUG_ON(!PageHead(page)); | |
992 | if (flags & FOLL_TOUCH) { | |
993 | pmd_t _pmd; | |
994 | /* | |
995 | * We should set the dirty bit only for FOLL_WRITE but | |
996 | * for now the dirty bit in the pmd is meaningless. | |
997 | * And if the dirty bit will become meaningful and | |
998 | * we'll only set it with FOLL_WRITE, an atomic | |
999 | * set_bit will be required on the pmd to set the | |
1000 | * young bit, instead of the current set_pmd_at. | |
1001 | */ | |
1002 | _pmd = pmd_mkyoung(pmd_mkdirty(*pmd)); | |
1003 | set_pmd_at(mm, addr & HPAGE_PMD_MASK, pmd, _pmd); | |
1004 | } | |
b676b293 DR |
1005 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
1006 | if (page->mapping && trylock_page(page)) { | |
1007 | lru_add_drain(); | |
1008 | if (page->mapping) | |
1009 | mlock_vma_page(page); | |
1010 | unlock_page(page); | |
1011 | } | |
1012 | } | |
71e3aac0 AA |
1013 | page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; |
1014 | VM_BUG_ON(!PageCompound(page)); | |
1015 | if (flags & FOLL_GET) | |
70b50f94 | 1016 | get_page_foll(page); |
71e3aac0 AA |
1017 | |
1018 | out: | |
1019 | return page; | |
1020 | } | |
1021 | ||
d10e63f2 | 1022 | /* NUMA hinting page fault entry point for trans huge pmds */ |
4daae3b4 MG |
1023 | int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1024 | unsigned long addr, pmd_t pmd, pmd_t *pmdp) | |
d10e63f2 | 1025 | { |
b32967ff | 1026 | struct page *page; |
d10e63f2 | 1027 | unsigned long haddr = addr & HPAGE_PMD_MASK; |
4daae3b4 | 1028 | int target_nid; |
03c5a6e1 | 1029 | int current_nid = -1; |
b32967ff MG |
1030 | bool migrated; |
1031 | bool page_locked = false; | |
d10e63f2 MG |
1032 | |
1033 | spin_lock(&mm->page_table_lock); | |
1034 | if (unlikely(!pmd_same(pmd, *pmdp))) | |
1035 | goto out_unlock; | |
1036 | ||
1037 | page = pmd_page(pmd); | |
4daae3b4 | 1038 | get_page(page); |
03c5a6e1 MG |
1039 | current_nid = page_to_nid(page); |
1040 | count_vm_numa_event(NUMA_HINT_FAULTS); | |
1041 | if (current_nid == numa_node_id()) | |
1042 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); | |
4daae3b4 MG |
1043 | |
1044 | target_nid = mpol_misplaced(page, vma, haddr); | |
b32967ff MG |
1045 | if (target_nid == -1) { |
1046 | put_page(page); | |
4daae3b4 | 1047 | goto clear_pmdnuma; |
b32967ff | 1048 | } |
4daae3b4 | 1049 | |
b32967ff MG |
1050 | /* Acquire the page lock to serialise THP migrations */ |
1051 | spin_unlock(&mm->page_table_lock); | |
1052 | lock_page(page); | |
1053 | page_locked = true; | |
4daae3b4 | 1054 | |
b32967ff | 1055 | /* Confirm the PTE did not while locked */ |
4daae3b4 | 1056 | spin_lock(&mm->page_table_lock); |
b32967ff MG |
1057 | if (unlikely(!pmd_same(pmd, *pmdp))) { |
1058 | unlock_page(page); | |
1059 | put_page(page); | |
4daae3b4 | 1060 | goto out_unlock; |
b32967ff MG |
1061 | } |
1062 | spin_unlock(&mm->page_table_lock); | |
4daae3b4 | 1063 | |
b32967ff MG |
1064 | /* Migrate the THP to the requested node */ |
1065 | migrated = migrate_misplaced_transhuge_page(mm, vma, | |
1066 | pmdp, pmd, addr, | |
1067 | page, target_nid); | |
1068 | if (migrated) | |
1069 | current_nid = target_nid; | |
1070 | else { | |
1071 | spin_lock(&mm->page_table_lock); | |
1072 | if (unlikely(!pmd_same(pmd, *pmdp))) { | |
1073 | unlock_page(page); | |
1074 | goto out_unlock; | |
1075 | } | |
1076 | goto clear_pmdnuma; | |
1077 | } | |
1078 | ||
1079 | task_numa_fault(current_nid, HPAGE_PMD_NR, migrated); | |
1080 | return 0; | |
1081 | ||
1082 | clear_pmdnuma: | |
d10e63f2 MG |
1083 | pmd = pmd_mknonnuma(pmd); |
1084 | set_pmd_at(mm, haddr, pmdp, pmd); | |
1085 | VM_BUG_ON(pmd_numa(*pmdp)); | |
1086 | update_mmu_cache_pmd(vma, addr, pmdp); | |
b32967ff MG |
1087 | if (page_locked) |
1088 | unlock_page(page); | |
d10e63f2 MG |
1089 | |
1090 | out_unlock: | |
1091 | spin_unlock(&mm->page_table_lock); | |
b32967ff MG |
1092 | if (current_nid != -1) |
1093 | task_numa_fault(current_nid, HPAGE_PMD_NR, migrated); | |
d10e63f2 MG |
1094 | return 0; |
1095 | } | |
1096 | ||
71e3aac0 | 1097 | int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, |
f21760b1 | 1098 | pmd_t *pmd, unsigned long addr) |
71e3aac0 AA |
1099 | { |
1100 | int ret = 0; | |
1101 | ||
025c5b24 NH |
1102 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1103 | struct page *page; | |
1104 | pgtable_t pgtable; | |
f5c8ad47 | 1105 | pmd_t orig_pmd; |
e3ebcf64 | 1106 | pgtable = pgtable_trans_huge_withdraw(tlb->mm); |
f5c8ad47 DM |
1107 | orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd); |
1108 | page = pmd_page(orig_pmd); | |
025c5b24 NH |
1109 | tlb_remove_pmd_tlb_entry(tlb, pmd, addr); |
1110 | page_remove_rmap(page); | |
1111 | VM_BUG_ON(page_mapcount(page) < 0); | |
1112 | add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); | |
1113 | VM_BUG_ON(!PageHead(page)); | |
1114 | tlb->mm->nr_ptes--; | |
71e3aac0 | 1115 | spin_unlock(&tlb->mm->page_table_lock); |
025c5b24 NH |
1116 | tlb_remove_page(tlb, page); |
1117 | pte_free(tlb->mm, pgtable); | |
1118 | ret = 1; | |
1119 | } | |
71e3aac0 AA |
1120 | return ret; |
1121 | } | |
1122 | ||
0ca1634d JW |
1123 | int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
1124 | unsigned long addr, unsigned long end, | |
1125 | unsigned char *vec) | |
1126 | { | |
1127 | int ret = 0; | |
1128 | ||
025c5b24 NH |
1129 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1130 | /* | |
1131 | * All logical pages in the range are present | |
1132 | * if backed by a huge page. | |
1133 | */ | |
0ca1634d | 1134 | spin_unlock(&vma->vm_mm->page_table_lock); |
025c5b24 NH |
1135 | memset(vec, 1, (end - addr) >> PAGE_SHIFT); |
1136 | ret = 1; | |
1137 | } | |
0ca1634d JW |
1138 | |
1139 | return ret; | |
1140 | } | |
1141 | ||
37a1c49a AA |
1142 | int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, |
1143 | unsigned long old_addr, | |
1144 | unsigned long new_addr, unsigned long old_end, | |
1145 | pmd_t *old_pmd, pmd_t *new_pmd) | |
1146 | { | |
1147 | int ret = 0; | |
1148 | pmd_t pmd; | |
1149 | ||
1150 | struct mm_struct *mm = vma->vm_mm; | |
1151 | ||
1152 | if ((old_addr & ~HPAGE_PMD_MASK) || | |
1153 | (new_addr & ~HPAGE_PMD_MASK) || | |
1154 | old_end - old_addr < HPAGE_PMD_SIZE || | |
1155 | (new_vma->vm_flags & VM_NOHUGEPAGE)) | |
1156 | goto out; | |
1157 | ||
1158 | /* | |
1159 | * The destination pmd shouldn't be established, free_pgtables() | |
1160 | * should have release it. | |
1161 | */ | |
1162 | if (WARN_ON(!pmd_none(*new_pmd))) { | |
1163 | VM_BUG_ON(pmd_trans_huge(*new_pmd)); | |
1164 | goto out; | |
1165 | } | |
1166 | ||
025c5b24 NH |
1167 | ret = __pmd_trans_huge_lock(old_pmd, vma); |
1168 | if (ret == 1) { | |
1169 | pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); | |
1170 | VM_BUG_ON(!pmd_none(*new_pmd)); | |
1171 | set_pmd_at(mm, new_addr, new_pmd, pmd); | |
37a1c49a AA |
1172 | spin_unlock(&mm->page_table_lock); |
1173 | } | |
1174 | out: | |
1175 | return ret; | |
1176 | } | |
1177 | ||
cd7548ab | 1178 | int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, |
4b10e7d5 | 1179 | unsigned long addr, pgprot_t newprot, int prot_numa) |
cd7548ab JW |
1180 | { |
1181 | struct mm_struct *mm = vma->vm_mm; | |
1182 | int ret = 0; | |
1183 | ||
025c5b24 NH |
1184 | if (__pmd_trans_huge_lock(pmd, vma) == 1) { |
1185 | pmd_t entry; | |
1186 | entry = pmdp_get_and_clear(mm, addr, pmd); | |
4b10e7d5 MG |
1187 | if (!prot_numa) |
1188 | entry = pmd_modify(entry, newprot); | |
1189 | else { | |
1190 | struct page *page = pmd_page(*pmd); | |
1191 | ||
1192 | /* only check non-shared pages */ | |
1193 | if (page_mapcount(page) == 1 && | |
1194 | !pmd_numa(*pmd)) { | |
1195 | entry = pmd_mknuma(entry); | |
1196 | } | |
1197 | } | |
025c5b24 NH |
1198 | set_pmd_at(mm, addr, pmd, entry); |
1199 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1200 | ret = 1; | |
1201 | } | |
1202 | ||
1203 | return ret; | |
1204 | } | |
1205 | ||
1206 | /* | |
1207 | * Returns 1 if a given pmd maps a stable (not under splitting) thp. | |
1208 | * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. | |
1209 | * | |
1210 | * Note that if it returns 1, this routine returns without unlocking page | |
1211 | * table locks. So callers must unlock them. | |
1212 | */ | |
1213 | int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) | |
1214 | { | |
1215 | spin_lock(&vma->vm_mm->page_table_lock); | |
cd7548ab JW |
1216 | if (likely(pmd_trans_huge(*pmd))) { |
1217 | if (unlikely(pmd_trans_splitting(*pmd))) { | |
025c5b24 | 1218 | spin_unlock(&vma->vm_mm->page_table_lock); |
cd7548ab | 1219 | wait_split_huge_page(vma->anon_vma, pmd); |
025c5b24 | 1220 | return -1; |
cd7548ab | 1221 | } else { |
025c5b24 NH |
1222 | /* Thp mapped by 'pmd' is stable, so we can |
1223 | * handle it as it is. */ | |
1224 | return 1; | |
cd7548ab | 1225 | } |
025c5b24 NH |
1226 | } |
1227 | spin_unlock(&vma->vm_mm->page_table_lock); | |
1228 | return 0; | |
cd7548ab JW |
1229 | } |
1230 | ||
71e3aac0 AA |
1231 | pmd_t *page_check_address_pmd(struct page *page, |
1232 | struct mm_struct *mm, | |
1233 | unsigned long address, | |
1234 | enum page_check_address_pmd_flag flag) | |
1235 | { | |
1236 | pgd_t *pgd; | |
1237 | pud_t *pud; | |
1238 | pmd_t *pmd, *ret = NULL; | |
1239 | ||
1240 | if (address & ~HPAGE_PMD_MASK) | |
1241 | goto out; | |
1242 | ||
1243 | pgd = pgd_offset(mm, address); | |
1244 | if (!pgd_present(*pgd)) | |
1245 | goto out; | |
1246 | ||
1247 | pud = pud_offset(pgd, address); | |
1248 | if (!pud_present(*pud)) | |
1249 | goto out; | |
1250 | ||
1251 | pmd = pmd_offset(pud, address); | |
1252 | if (pmd_none(*pmd)) | |
1253 | goto out; | |
1254 | if (pmd_page(*pmd) != page) | |
1255 | goto out; | |
94fcc585 AA |
1256 | /* |
1257 | * split_vma() may create temporary aliased mappings. There is | |
1258 | * no risk as long as all huge pmd are found and have their | |
1259 | * splitting bit set before __split_huge_page_refcount | |
1260 | * runs. Finding the same huge pmd more than once during the | |
1261 | * same rmap walk is not a problem. | |
1262 | */ | |
1263 | if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG && | |
1264 | pmd_trans_splitting(*pmd)) | |
1265 | goto out; | |
71e3aac0 AA |
1266 | if (pmd_trans_huge(*pmd)) { |
1267 | VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG && | |
1268 | !pmd_trans_splitting(*pmd)); | |
1269 | ret = pmd; | |
1270 | } | |
1271 | out: | |
1272 | return ret; | |
1273 | } | |
1274 | ||
1275 | static int __split_huge_page_splitting(struct page *page, | |
1276 | struct vm_area_struct *vma, | |
1277 | unsigned long address) | |
1278 | { | |
1279 | struct mm_struct *mm = vma->vm_mm; | |
1280 | pmd_t *pmd; | |
1281 | int ret = 0; | |
2ec74c3e SG |
1282 | /* For mmu_notifiers */ |
1283 | const unsigned long mmun_start = address; | |
1284 | const unsigned long mmun_end = address + HPAGE_PMD_SIZE; | |
71e3aac0 | 1285 | |
2ec74c3e | 1286 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1287 | spin_lock(&mm->page_table_lock); |
1288 | pmd = page_check_address_pmd(page, mm, address, | |
1289 | PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG); | |
1290 | if (pmd) { | |
1291 | /* | |
1292 | * We can't temporarily set the pmd to null in order | |
1293 | * to split it, the pmd must remain marked huge at all | |
1294 | * times or the VM won't take the pmd_trans_huge paths | |
2b575eb6 | 1295 | * and it won't wait on the anon_vma->root->mutex to |
71e3aac0 AA |
1296 | * serialize against split_huge_page*. |
1297 | */ | |
2ec74c3e | 1298 | pmdp_splitting_flush(vma, address, pmd); |
71e3aac0 AA |
1299 | ret = 1; |
1300 | } | |
1301 | spin_unlock(&mm->page_table_lock); | |
2ec74c3e | 1302 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
71e3aac0 AA |
1303 | |
1304 | return ret; | |
1305 | } | |
1306 | ||
1307 | static void __split_huge_page_refcount(struct page *page) | |
1308 | { | |
1309 | int i; | |
71e3aac0 | 1310 | struct zone *zone = page_zone(page); |
fa9add64 | 1311 | struct lruvec *lruvec; |
70b50f94 | 1312 | int tail_count = 0; |
71e3aac0 AA |
1313 | |
1314 | /* prevent PageLRU to go away from under us, and freeze lru stats */ | |
1315 | spin_lock_irq(&zone->lru_lock); | |
fa9add64 HD |
1316 | lruvec = mem_cgroup_page_lruvec(page, zone); |
1317 | ||
71e3aac0 | 1318 | compound_lock(page); |
e94c8a9c KH |
1319 | /* complete memcg works before add pages to LRU */ |
1320 | mem_cgroup_split_huge_fixup(page); | |
71e3aac0 | 1321 | |
45676885 | 1322 | for (i = HPAGE_PMD_NR - 1; i >= 1; i--) { |
71e3aac0 AA |
1323 | struct page *page_tail = page + i; |
1324 | ||
70b50f94 AA |
1325 | /* tail_page->_mapcount cannot change */ |
1326 | BUG_ON(page_mapcount(page_tail) < 0); | |
1327 | tail_count += page_mapcount(page_tail); | |
1328 | /* check for overflow */ | |
1329 | BUG_ON(tail_count < 0); | |
1330 | BUG_ON(atomic_read(&page_tail->_count) != 0); | |
1331 | /* | |
1332 | * tail_page->_count is zero and not changing from | |
1333 | * under us. But get_page_unless_zero() may be running | |
1334 | * from under us on the tail_page. If we used | |
1335 | * atomic_set() below instead of atomic_add(), we | |
1336 | * would then run atomic_set() concurrently with | |
1337 | * get_page_unless_zero(), and atomic_set() is | |
1338 | * implemented in C not using locked ops. spin_unlock | |
1339 | * on x86 sometime uses locked ops because of PPro | |
1340 | * errata 66, 92, so unless somebody can guarantee | |
1341 | * atomic_set() here would be safe on all archs (and | |
1342 | * not only on x86), it's safer to use atomic_add(). | |
1343 | */ | |
1344 | atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, | |
1345 | &page_tail->_count); | |
71e3aac0 AA |
1346 | |
1347 | /* after clearing PageTail the gup refcount can be released */ | |
1348 | smp_mb(); | |
1349 | ||
a6d30ddd JD |
1350 | /* |
1351 | * retain hwpoison flag of the poisoned tail page: | |
1352 | * fix for the unsuitable process killed on Guest Machine(KVM) | |
1353 | * by the memory-failure. | |
1354 | */ | |
1355 | page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP | __PG_HWPOISON; | |
71e3aac0 AA |
1356 | page_tail->flags |= (page->flags & |
1357 | ((1L << PG_referenced) | | |
1358 | (1L << PG_swapbacked) | | |
1359 | (1L << PG_mlocked) | | |
1360 | (1L << PG_uptodate))); | |
1361 | page_tail->flags |= (1L << PG_dirty); | |
1362 | ||
70b50f94 | 1363 | /* clear PageTail before overwriting first_page */ |
71e3aac0 AA |
1364 | smp_wmb(); |
1365 | ||
1366 | /* | |
1367 | * __split_huge_page_splitting() already set the | |
1368 | * splitting bit in all pmd that could map this | |
1369 | * hugepage, that will ensure no CPU can alter the | |
1370 | * mapcount on the head page. The mapcount is only | |
1371 | * accounted in the head page and it has to be | |
1372 | * transferred to all tail pages in the below code. So | |
1373 | * for this code to be safe, the split the mapcount | |
1374 | * can't change. But that doesn't mean userland can't | |
1375 | * keep changing and reading the page contents while | |
1376 | * we transfer the mapcount, so the pmd splitting | |
1377 | * status is achieved setting a reserved bit in the | |
1378 | * pmd, not by clearing the present bit. | |
1379 | */ | |
71e3aac0 AA |
1380 | page_tail->_mapcount = page->_mapcount; |
1381 | ||
1382 | BUG_ON(page_tail->mapping); | |
1383 | page_tail->mapping = page->mapping; | |
1384 | ||
45676885 | 1385 | page_tail->index = page->index + i; |
5aa80374 | 1386 | page_xchg_last_nid(page_tail, page_last_nid(page)); |
71e3aac0 AA |
1387 | |
1388 | BUG_ON(!PageAnon(page_tail)); | |
1389 | BUG_ON(!PageUptodate(page_tail)); | |
1390 | BUG_ON(!PageDirty(page_tail)); | |
1391 | BUG_ON(!PageSwapBacked(page_tail)); | |
1392 | ||
fa9add64 | 1393 | lru_add_page_tail(page, page_tail, lruvec); |
71e3aac0 | 1394 | } |
70b50f94 AA |
1395 | atomic_sub(tail_count, &page->_count); |
1396 | BUG_ON(atomic_read(&page->_count) <= 0); | |
71e3aac0 | 1397 | |
fa9add64 | 1398 | __mod_zone_page_state(zone, NR_ANON_TRANSPARENT_HUGEPAGES, -1); |
79134171 AA |
1399 | __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR); |
1400 | ||
71e3aac0 AA |
1401 | ClearPageCompound(page); |
1402 | compound_unlock(page); | |
1403 | spin_unlock_irq(&zone->lru_lock); | |
1404 | ||
1405 | for (i = 1; i < HPAGE_PMD_NR; i++) { | |
1406 | struct page *page_tail = page + i; | |
1407 | BUG_ON(page_count(page_tail) <= 0); | |
1408 | /* | |
1409 | * Tail pages may be freed if there wasn't any mapping | |
1410 | * like if add_to_swap() is running on a lru page that | |
1411 | * had its mapping zapped. And freeing these pages | |
1412 | * requires taking the lru_lock so we do the put_page | |
1413 | * of the tail pages after the split is complete. | |
1414 | */ | |
1415 | put_page(page_tail); | |
1416 | } | |
1417 | ||
1418 | /* | |
1419 | * Only the head page (now become a regular page) is required | |
1420 | * to be pinned by the caller. | |
1421 | */ | |
1422 | BUG_ON(page_count(page) <= 0); | |
1423 | } | |
1424 | ||
1425 | static int __split_huge_page_map(struct page *page, | |
1426 | struct vm_area_struct *vma, | |
1427 | unsigned long address) | |
1428 | { | |
1429 | struct mm_struct *mm = vma->vm_mm; | |
1430 | pmd_t *pmd, _pmd; | |
1431 | int ret = 0, i; | |
1432 | pgtable_t pgtable; | |
1433 | unsigned long haddr; | |
1434 | ||
1435 | spin_lock(&mm->page_table_lock); | |
1436 | pmd = page_check_address_pmd(page, mm, address, | |
1437 | PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); | |
1438 | if (pmd) { | |
e3ebcf64 | 1439 | pgtable = pgtable_trans_huge_withdraw(mm); |
71e3aac0 AA |
1440 | pmd_populate(mm, &_pmd, pgtable); |
1441 | ||
e3ebcf64 GS |
1442 | haddr = address; |
1443 | for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { | |
71e3aac0 AA |
1444 | pte_t *pte, entry; |
1445 | BUG_ON(PageCompound(page+i)); | |
1446 | entry = mk_pte(page + i, vma->vm_page_prot); | |
1447 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1448 | if (!pmd_write(*pmd)) | |
1449 | entry = pte_wrprotect(entry); | |
1450 | else | |
1451 | BUG_ON(page_mapcount(page) != 1); | |
1452 | if (!pmd_young(*pmd)) | |
1453 | entry = pte_mkold(entry); | |
1ba6e0b5 AA |
1454 | if (pmd_numa(*pmd)) |
1455 | entry = pte_mknuma(entry); | |
71e3aac0 AA |
1456 | pte = pte_offset_map(&_pmd, haddr); |
1457 | BUG_ON(!pte_none(*pte)); | |
1458 | set_pte_at(mm, haddr, pte, entry); | |
1459 | pte_unmap(pte); | |
1460 | } | |
1461 | ||
71e3aac0 AA |
1462 | smp_wmb(); /* make pte visible before pmd */ |
1463 | /* | |
1464 | * Up to this point the pmd is present and huge and | |
1465 | * userland has the whole access to the hugepage | |
1466 | * during the split (which happens in place). If we | |
1467 | * overwrite the pmd with the not-huge version | |
1468 | * pointing to the pte here (which of course we could | |
1469 | * if all CPUs were bug free), userland could trigger | |
1470 | * a small page size TLB miss on the small sized TLB | |
1471 | * while the hugepage TLB entry is still established | |
1472 | * in the huge TLB. Some CPU doesn't like that. See | |
1473 | * http://support.amd.com/us/Processor_TechDocs/41322.pdf, | |
1474 | * Erratum 383 on page 93. Intel should be safe but is | |
1475 | * also warns that it's only safe if the permission | |
1476 | * and cache attributes of the two entries loaded in | |
1477 | * the two TLB is identical (which should be the case | |
1478 | * here). But it is generally safer to never allow | |
1479 | * small and huge TLB entries for the same virtual | |
1480 | * address to be loaded simultaneously. So instead of | |
1481 | * doing "pmd_populate(); flush_tlb_range();" we first | |
1482 | * mark the current pmd notpresent (atomically because | |
1483 | * here the pmd_trans_huge and pmd_trans_splitting | |
1484 | * must remain set at all times on the pmd until the | |
1485 | * split is complete for this pmd), then we flush the | |
1486 | * SMP TLB and finally we write the non-huge version | |
1487 | * of the pmd entry with pmd_populate. | |
1488 | */ | |
46dcde73 | 1489 | pmdp_invalidate(vma, address, pmd); |
71e3aac0 AA |
1490 | pmd_populate(mm, pmd, pgtable); |
1491 | ret = 1; | |
1492 | } | |
1493 | spin_unlock(&mm->page_table_lock); | |
1494 | ||
1495 | return ret; | |
1496 | } | |
1497 | ||
2b575eb6 | 1498 | /* must be called with anon_vma->root->mutex hold */ |
71e3aac0 AA |
1499 | static void __split_huge_page(struct page *page, |
1500 | struct anon_vma *anon_vma) | |
1501 | { | |
1502 | int mapcount, mapcount2; | |
bf181b9f | 1503 | pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT); |
71e3aac0 AA |
1504 | struct anon_vma_chain *avc; |
1505 | ||
1506 | BUG_ON(!PageHead(page)); | |
1507 | BUG_ON(PageTail(page)); | |
1508 | ||
1509 | mapcount = 0; | |
bf181b9f | 1510 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1511 | struct vm_area_struct *vma = avc->vma; |
1512 | unsigned long addr = vma_address(page, vma); | |
1513 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1514 | mapcount += __split_huge_page_splitting(page, vma, addr); |
1515 | } | |
05759d38 AA |
1516 | /* |
1517 | * It is critical that new vmas are added to the tail of the | |
1518 | * anon_vma list. This guarantes that if copy_huge_pmd() runs | |
1519 | * and establishes a child pmd before | |
1520 | * __split_huge_page_splitting() freezes the parent pmd (so if | |
1521 | * we fail to prevent copy_huge_pmd() from running until the | |
1522 | * whole __split_huge_page() is complete), we will still see | |
1523 | * the newly established pmd of the child later during the | |
1524 | * walk, to be able to set it as pmd_trans_splitting too. | |
1525 | */ | |
1526 | if (mapcount != page_mapcount(page)) | |
1527 | printk(KERN_ERR "mapcount %d page_mapcount %d\n", | |
1528 | mapcount, page_mapcount(page)); | |
71e3aac0 AA |
1529 | BUG_ON(mapcount != page_mapcount(page)); |
1530 | ||
1531 | __split_huge_page_refcount(page); | |
1532 | ||
1533 | mapcount2 = 0; | |
bf181b9f | 1534 | anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root, pgoff, pgoff) { |
71e3aac0 AA |
1535 | struct vm_area_struct *vma = avc->vma; |
1536 | unsigned long addr = vma_address(page, vma); | |
1537 | BUG_ON(is_vma_temporary_stack(vma)); | |
71e3aac0 AA |
1538 | mapcount2 += __split_huge_page_map(page, vma, addr); |
1539 | } | |
05759d38 AA |
1540 | if (mapcount != mapcount2) |
1541 | printk(KERN_ERR "mapcount %d mapcount2 %d page_mapcount %d\n", | |
1542 | mapcount, mapcount2, page_mapcount(page)); | |
71e3aac0 AA |
1543 | BUG_ON(mapcount != mapcount2); |
1544 | } | |
1545 | ||
1546 | int split_huge_page(struct page *page) | |
1547 | { | |
1548 | struct anon_vma *anon_vma; | |
1549 | int ret = 1; | |
1550 | ||
1551 | BUG_ON(!PageAnon(page)); | |
1552 | anon_vma = page_lock_anon_vma(page); | |
1553 | if (!anon_vma) | |
1554 | goto out; | |
1555 | ret = 0; | |
1556 | if (!PageCompound(page)) | |
1557 | goto out_unlock; | |
1558 | ||
1559 | BUG_ON(!PageSwapBacked(page)); | |
1560 | __split_huge_page(page, anon_vma); | |
81ab4201 | 1561 | count_vm_event(THP_SPLIT); |
71e3aac0 AA |
1562 | |
1563 | BUG_ON(PageCompound(page)); | |
1564 | out_unlock: | |
1565 | page_unlock_anon_vma(anon_vma); | |
1566 | out: | |
1567 | return ret; | |
1568 | } | |
1569 | ||
4b6e1e37 | 1570 | #define VM_NO_THP (VM_SPECIAL|VM_MIXEDMAP|VM_HUGETLB|VM_SHARED|VM_MAYSHARE) |
78f11a25 | 1571 | |
60ab3244 AA |
1572 | int hugepage_madvise(struct vm_area_struct *vma, |
1573 | unsigned long *vm_flags, int advice) | |
0af4e98b | 1574 | { |
8e72033f GS |
1575 | struct mm_struct *mm = vma->vm_mm; |
1576 | ||
a664b2d8 AA |
1577 | switch (advice) { |
1578 | case MADV_HUGEPAGE: | |
1579 | /* | |
1580 | * Be somewhat over-protective like KSM for now! | |
1581 | */ | |
78f11a25 | 1582 | if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) |
a664b2d8 | 1583 | return -EINVAL; |
8e72033f GS |
1584 | if (mm->def_flags & VM_NOHUGEPAGE) |
1585 | return -EINVAL; | |
a664b2d8 AA |
1586 | *vm_flags &= ~VM_NOHUGEPAGE; |
1587 | *vm_flags |= VM_HUGEPAGE; | |
60ab3244 AA |
1588 | /* |
1589 | * If the vma become good for khugepaged to scan, | |
1590 | * register it here without waiting a page fault that | |
1591 | * may not happen any time soon. | |
1592 | */ | |
1593 | if (unlikely(khugepaged_enter_vma_merge(vma))) | |
1594 | return -ENOMEM; | |
a664b2d8 AA |
1595 | break; |
1596 | case MADV_NOHUGEPAGE: | |
1597 | /* | |
1598 | * Be somewhat over-protective like KSM for now! | |
1599 | */ | |
78f11a25 | 1600 | if (*vm_flags & (VM_NOHUGEPAGE | VM_NO_THP)) |
a664b2d8 AA |
1601 | return -EINVAL; |
1602 | *vm_flags &= ~VM_HUGEPAGE; | |
1603 | *vm_flags |= VM_NOHUGEPAGE; | |
60ab3244 AA |
1604 | /* |
1605 | * Setting VM_NOHUGEPAGE will prevent khugepaged from scanning | |
1606 | * this vma even if we leave the mm registered in khugepaged if | |
1607 | * it got registered before VM_NOHUGEPAGE was set. | |
1608 | */ | |
a664b2d8 AA |
1609 | break; |
1610 | } | |
0af4e98b AA |
1611 | |
1612 | return 0; | |
1613 | } | |
1614 | ||
ba76149f AA |
1615 | static int __init khugepaged_slab_init(void) |
1616 | { | |
1617 | mm_slot_cache = kmem_cache_create("khugepaged_mm_slot", | |
1618 | sizeof(struct mm_slot), | |
1619 | __alignof__(struct mm_slot), 0, NULL); | |
1620 | if (!mm_slot_cache) | |
1621 | return -ENOMEM; | |
1622 | ||
1623 | return 0; | |
1624 | } | |
1625 | ||
1626 | static void __init khugepaged_slab_free(void) | |
1627 | { | |
1628 | kmem_cache_destroy(mm_slot_cache); | |
1629 | mm_slot_cache = NULL; | |
1630 | } | |
1631 | ||
1632 | static inline struct mm_slot *alloc_mm_slot(void) | |
1633 | { | |
1634 | if (!mm_slot_cache) /* initialization failed */ | |
1635 | return NULL; | |
1636 | return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); | |
1637 | } | |
1638 | ||
1639 | static inline void free_mm_slot(struct mm_slot *mm_slot) | |
1640 | { | |
1641 | kmem_cache_free(mm_slot_cache, mm_slot); | |
1642 | } | |
1643 | ||
1644 | static int __init mm_slots_hash_init(void) | |
1645 | { | |
1646 | mm_slots_hash = kzalloc(MM_SLOTS_HASH_HEADS * sizeof(struct hlist_head), | |
1647 | GFP_KERNEL); | |
1648 | if (!mm_slots_hash) | |
1649 | return -ENOMEM; | |
1650 | return 0; | |
1651 | } | |
1652 | ||
1653 | #if 0 | |
1654 | static void __init mm_slots_hash_free(void) | |
1655 | { | |
1656 | kfree(mm_slots_hash); | |
1657 | mm_slots_hash = NULL; | |
1658 | } | |
1659 | #endif | |
1660 | ||
1661 | static struct mm_slot *get_mm_slot(struct mm_struct *mm) | |
1662 | { | |
1663 | struct mm_slot *mm_slot; | |
1664 | struct hlist_head *bucket; | |
1665 | struct hlist_node *node; | |
1666 | ||
1667 | bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) | |
1668 | % MM_SLOTS_HASH_HEADS]; | |
1669 | hlist_for_each_entry(mm_slot, node, bucket, hash) { | |
1670 | if (mm == mm_slot->mm) | |
1671 | return mm_slot; | |
1672 | } | |
1673 | return NULL; | |
1674 | } | |
1675 | ||
1676 | static void insert_to_mm_slots_hash(struct mm_struct *mm, | |
1677 | struct mm_slot *mm_slot) | |
1678 | { | |
1679 | struct hlist_head *bucket; | |
1680 | ||
1681 | bucket = &mm_slots_hash[((unsigned long)mm / sizeof(struct mm_struct)) | |
1682 | % MM_SLOTS_HASH_HEADS]; | |
1683 | mm_slot->mm = mm; | |
1684 | hlist_add_head(&mm_slot->hash, bucket); | |
1685 | } | |
1686 | ||
1687 | static inline int khugepaged_test_exit(struct mm_struct *mm) | |
1688 | { | |
1689 | return atomic_read(&mm->mm_users) == 0; | |
1690 | } | |
1691 | ||
1692 | int __khugepaged_enter(struct mm_struct *mm) | |
1693 | { | |
1694 | struct mm_slot *mm_slot; | |
1695 | int wakeup; | |
1696 | ||
1697 | mm_slot = alloc_mm_slot(); | |
1698 | if (!mm_slot) | |
1699 | return -ENOMEM; | |
1700 | ||
1701 | /* __khugepaged_exit() must not run from under us */ | |
1702 | VM_BUG_ON(khugepaged_test_exit(mm)); | |
1703 | if (unlikely(test_and_set_bit(MMF_VM_HUGEPAGE, &mm->flags))) { | |
1704 | free_mm_slot(mm_slot); | |
1705 | return 0; | |
1706 | } | |
1707 | ||
1708 | spin_lock(&khugepaged_mm_lock); | |
1709 | insert_to_mm_slots_hash(mm, mm_slot); | |
1710 | /* | |
1711 | * Insert just behind the scanning cursor, to let the area settle | |
1712 | * down a little. | |
1713 | */ | |
1714 | wakeup = list_empty(&khugepaged_scan.mm_head); | |
1715 | list_add_tail(&mm_slot->mm_node, &khugepaged_scan.mm_head); | |
1716 | spin_unlock(&khugepaged_mm_lock); | |
1717 | ||
1718 | atomic_inc(&mm->mm_count); | |
1719 | if (wakeup) | |
1720 | wake_up_interruptible(&khugepaged_wait); | |
1721 | ||
1722 | return 0; | |
1723 | } | |
1724 | ||
1725 | int khugepaged_enter_vma_merge(struct vm_area_struct *vma) | |
1726 | { | |
1727 | unsigned long hstart, hend; | |
1728 | if (!vma->anon_vma) | |
1729 | /* | |
1730 | * Not yet faulted in so we will register later in the | |
1731 | * page fault if needed. | |
1732 | */ | |
1733 | return 0; | |
78f11a25 | 1734 | if (vma->vm_ops) |
ba76149f AA |
1735 | /* khugepaged not yet working on file or special mappings */ |
1736 | return 0; | |
b3b9c293 | 1737 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); |
ba76149f AA |
1738 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; |
1739 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
1740 | if (hstart < hend) | |
1741 | return khugepaged_enter(vma); | |
1742 | return 0; | |
1743 | } | |
1744 | ||
1745 | void __khugepaged_exit(struct mm_struct *mm) | |
1746 | { | |
1747 | struct mm_slot *mm_slot; | |
1748 | int free = 0; | |
1749 | ||
1750 | spin_lock(&khugepaged_mm_lock); | |
1751 | mm_slot = get_mm_slot(mm); | |
1752 | if (mm_slot && khugepaged_scan.mm_slot != mm_slot) { | |
1753 | hlist_del(&mm_slot->hash); | |
1754 | list_del(&mm_slot->mm_node); | |
1755 | free = 1; | |
1756 | } | |
d788e80a | 1757 | spin_unlock(&khugepaged_mm_lock); |
ba76149f AA |
1758 | |
1759 | if (free) { | |
ba76149f AA |
1760 | clear_bit(MMF_VM_HUGEPAGE, &mm->flags); |
1761 | free_mm_slot(mm_slot); | |
1762 | mmdrop(mm); | |
1763 | } else if (mm_slot) { | |
ba76149f AA |
1764 | /* |
1765 | * This is required to serialize against | |
1766 | * khugepaged_test_exit() (which is guaranteed to run | |
1767 | * under mmap sem read mode). Stop here (after we | |
1768 | * return all pagetables will be destroyed) until | |
1769 | * khugepaged has finished working on the pagetables | |
1770 | * under the mmap_sem. | |
1771 | */ | |
1772 | down_write(&mm->mmap_sem); | |
1773 | up_write(&mm->mmap_sem); | |
d788e80a | 1774 | } |
ba76149f AA |
1775 | } |
1776 | ||
1777 | static void release_pte_page(struct page *page) | |
1778 | { | |
1779 | /* 0 stands for page_is_file_cache(page) == false */ | |
1780 | dec_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
1781 | unlock_page(page); | |
1782 | putback_lru_page(page); | |
1783 | } | |
1784 | ||
1785 | static void release_pte_pages(pte_t *pte, pte_t *_pte) | |
1786 | { | |
1787 | while (--_pte >= pte) { | |
1788 | pte_t pteval = *_pte; | |
1789 | if (!pte_none(pteval)) | |
1790 | release_pte_page(pte_page(pteval)); | |
1791 | } | |
1792 | } | |
1793 | ||
1794 | static void release_all_pte_pages(pte_t *pte) | |
1795 | { | |
1796 | release_pte_pages(pte, pte + HPAGE_PMD_NR); | |
1797 | } | |
1798 | ||
1799 | static int __collapse_huge_page_isolate(struct vm_area_struct *vma, | |
1800 | unsigned long address, | |
1801 | pte_t *pte) | |
1802 | { | |
1803 | struct page *page; | |
1804 | pte_t *_pte; | |
1805 | int referenced = 0, isolated = 0, none = 0; | |
1806 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; | |
1807 | _pte++, address += PAGE_SIZE) { | |
1808 | pte_t pteval = *_pte; | |
1809 | if (pte_none(pteval)) { | |
1810 | if (++none <= khugepaged_max_ptes_none) | |
1811 | continue; | |
1812 | else { | |
1813 | release_pte_pages(pte, _pte); | |
1814 | goto out; | |
1815 | } | |
1816 | } | |
1817 | if (!pte_present(pteval) || !pte_write(pteval)) { | |
1818 | release_pte_pages(pte, _pte); | |
1819 | goto out; | |
1820 | } | |
1821 | page = vm_normal_page(vma, address, pteval); | |
1822 | if (unlikely(!page)) { | |
1823 | release_pte_pages(pte, _pte); | |
1824 | goto out; | |
1825 | } | |
1826 | VM_BUG_ON(PageCompound(page)); | |
1827 | BUG_ON(!PageAnon(page)); | |
1828 | VM_BUG_ON(!PageSwapBacked(page)); | |
1829 | ||
1830 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
1831 | if (page_count(page) != 1) { | |
1832 | release_pte_pages(pte, _pte); | |
1833 | goto out; | |
1834 | } | |
1835 | /* | |
1836 | * We can do it before isolate_lru_page because the | |
1837 | * page can't be freed from under us. NOTE: PG_lock | |
1838 | * is needed to serialize against split_huge_page | |
1839 | * when invoked from the VM. | |
1840 | */ | |
1841 | if (!trylock_page(page)) { | |
1842 | release_pte_pages(pte, _pte); | |
1843 | goto out; | |
1844 | } | |
1845 | /* | |
1846 | * Isolate the page to avoid collapsing an hugepage | |
1847 | * currently in use by the VM. | |
1848 | */ | |
1849 | if (isolate_lru_page(page)) { | |
1850 | unlock_page(page); | |
1851 | release_pte_pages(pte, _pte); | |
1852 | goto out; | |
1853 | } | |
1854 | /* 0 stands for page_is_file_cache(page) == false */ | |
1855 | inc_zone_page_state(page, NR_ISOLATED_ANON + 0); | |
1856 | VM_BUG_ON(!PageLocked(page)); | |
1857 | VM_BUG_ON(PageLRU(page)); | |
1858 | ||
1859 | /* If there is no mapped pte young don't collapse the page */ | |
8ee53820 AA |
1860 | if (pte_young(pteval) || PageReferenced(page) || |
1861 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
1862 | referenced = 1; |
1863 | } | |
1864 | if (unlikely(!referenced)) | |
1865 | release_all_pte_pages(pte); | |
1866 | else | |
1867 | isolated = 1; | |
1868 | out: | |
1869 | return isolated; | |
1870 | } | |
1871 | ||
1872 | static void __collapse_huge_page_copy(pte_t *pte, struct page *page, | |
1873 | struct vm_area_struct *vma, | |
1874 | unsigned long address, | |
1875 | spinlock_t *ptl) | |
1876 | { | |
1877 | pte_t *_pte; | |
1878 | for (_pte = pte; _pte < pte+HPAGE_PMD_NR; _pte++) { | |
1879 | pte_t pteval = *_pte; | |
1880 | struct page *src_page; | |
1881 | ||
1882 | if (pte_none(pteval)) { | |
1883 | clear_user_highpage(page, address); | |
1884 | add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); | |
1885 | } else { | |
1886 | src_page = pte_page(pteval); | |
1887 | copy_user_highpage(page, src_page, address, vma); | |
1888 | VM_BUG_ON(page_mapcount(src_page) != 1); | |
ba76149f AA |
1889 | release_pte_page(src_page); |
1890 | /* | |
1891 | * ptl mostly unnecessary, but preempt has to | |
1892 | * be disabled to update the per-cpu stats | |
1893 | * inside page_remove_rmap(). | |
1894 | */ | |
1895 | spin_lock(ptl); | |
1896 | /* | |
1897 | * paravirt calls inside pte_clear here are | |
1898 | * superfluous. | |
1899 | */ | |
1900 | pte_clear(vma->vm_mm, address, _pte); | |
1901 | page_remove_rmap(src_page); | |
1902 | spin_unlock(ptl); | |
1903 | free_page_and_swap_cache(src_page); | |
1904 | } | |
1905 | ||
1906 | address += PAGE_SIZE; | |
1907 | page++; | |
1908 | } | |
1909 | } | |
1910 | ||
26234f36 | 1911 | static void khugepaged_alloc_sleep(void) |
ba76149f | 1912 | { |
26234f36 XG |
1913 | wait_event_freezable_timeout(khugepaged_wait, false, |
1914 | msecs_to_jiffies(khugepaged_alloc_sleep_millisecs)); | |
1915 | } | |
ba76149f | 1916 | |
26234f36 XG |
1917 | #ifdef CONFIG_NUMA |
1918 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
1919 | { | |
1920 | if (IS_ERR(*hpage)) { | |
1921 | if (!*wait) | |
1922 | return false; | |
1923 | ||
1924 | *wait = false; | |
e3b4126c | 1925 | *hpage = NULL; |
26234f36 XG |
1926 | khugepaged_alloc_sleep(); |
1927 | } else if (*hpage) { | |
1928 | put_page(*hpage); | |
1929 | *hpage = NULL; | |
1930 | } | |
1931 | ||
1932 | return true; | |
1933 | } | |
1934 | ||
1935 | static struct page | |
1936 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
1937 | struct vm_area_struct *vma, unsigned long address, | |
1938 | int node) | |
1939 | { | |
0bbbc0b3 | 1940 | VM_BUG_ON(*hpage); |
ce83d217 AA |
1941 | /* |
1942 | * Allocate the page while the vma is still valid and under | |
1943 | * the mmap_sem read mode so there is no memory allocation | |
1944 | * later when we take the mmap_sem in write mode. This is more | |
1945 | * friendly behavior (OTOH it may actually hide bugs) to | |
1946 | * filesystems in userland with daemons allocating memory in | |
1947 | * the userland I/O paths. Allocating memory with the | |
1948 | * mmap_sem in read mode is good idea also to allow greater | |
1949 | * scalability. | |
1950 | */ | |
26234f36 | 1951 | *hpage = alloc_hugepage_vma(khugepaged_defrag(), vma, address, |
cc5d462f | 1952 | node, __GFP_OTHER_NODE); |
692e0b35 AA |
1953 | |
1954 | /* | |
1955 | * After allocating the hugepage, release the mmap_sem read lock in | |
1956 | * preparation for taking it in write mode. | |
1957 | */ | |
1958 | up_read(&mm->mmap_sem); | |
26234f36 | 1959 | if (unlikely(!*hpage)) { |
81ab4201 | 1960 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); |
ce83d217 | 1961 | *hpage = ERR_PTR(-ENOMEM); |
26234f36 | 1962 | return NULL; |
ce83d217 | 1963 | } |
26234f36 | 1964 | |
65b3c07b | 1965 | count_vm_event(THP_COLLAPSE_ALLOC); |
26234f36 XG |
1966 | return *hpage; |
1967 | } | |
1968 | #else | |
1969 | static struct page *khugepaged_alloc_hugepage(bool *wait) | |
1970 | { | |
1971 | struct page *hpage; | |
1972 | ||
1973 | do { | |
1974 | hpage = alloc_hugepage(khugepaged_defrag()); | |
1975 | if (!hpage) { | |
1976 | count_vm_event(THP_COLLAPSE_ALLOC_FAILED); | |
1977 | if (!*wait) | |
1978 | return NULL; | |
1979 | ||
1980 | *wait = false; | |
1981 | khugepaged_alloc_sleep(); | |
1982 | } else | |
1983 | count_vm_event(THP_COLLAPSE_ALLOC); | |
1984 | } while (unlikely(!hpage) && likely(khugepaged_enabled())); | |
1985 | ||
1986 | return hpage; | |
1987 | } | |
1988 | ||
1989 | static bool khugepaged_prealloc_page(struct page **hpage, bool *wait) | |
1990 | { | |
1991 | if (!*hpage) | |
1992 | *hpage = khugepaged_alloc_hugepage(wait); | |
1993 | ||
1994 | if (unlikely(!*hpage)) | |
1995 | return false; | |
1996 | ||
1997 | return true; | |
1998 | } | |
1999 | ||
2000 | static struct page | |
2001 | *khugepaged_alloc_page(struct page **hpage, struct mm_struct *mm, | |
2002 | struct vm_area_struct *vma, unsigned long address, | |
2003 | int node) | |
2004 | { | |
2005 | up_read(&mm->mmap_sem); | |
2006 | VM_BUG_ON(!*hpage); | |
2007 | return *hpage; | |
2008 | } | |
692e0b35 AA |
2009 | #endif |
2010 | ||
26234f36 XG |
2011 | static void collapse_huge_page(struct mm_struct *mm, |
2012 | unsigned long address, | |
2013 | struct page **hpage, | |
2014 | struct vm_area_struct *vma, | |
2015 | int node) | |
2016 | { | |
2017 | pgd_t *pgd; | |
2018 | pud_t *pud; | |
2019 | pmd_t *pmd, _pmd; | |
2020 | pte_t *pte; | |
2021 | pgtable_t pgtable; | |
2022 | struct page *new_page; | |
2023 | spinlock_t *ptl; | |
2024 | int isolated; | |
2025 | unsigned long hstart, hend; | |
2ec74c3e SG |
2026 | unsigned long mmun_start; /* For mmu_notifiers */ |
2027 | unsigned long mmun_end; /* For mmu_notifiers */ | |
26234f36 XG |
2028 | |
2029 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2030 | ||
2031 | /* release the mmap_sem read lock. */ | |
2032 | new_page = khugepaged_alloc_page(hpage, mm, vma, address, node); | |
2033 | if (!new_page) | |
2034 | return; | |
2035 | ||
420256ef | 2036 | if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) |
ce83d217 | 2037 | return; |
ba76149f AA |
2038 | |
2039 | /* | |
2040 | * Prevent all access to pagetables with the exception of | |
2041 | * gup_fast later hanlded by the ptep_clear_flush and the VM | |
2042 | * handled by the anon_vma lock + PG_lock. | |
2043 | */ | |
2044 | down_write(&mm->mmap_sem); | |
2045 | if (unlikely(khugepaged_test_exit(mm))) | |
2046 | goto out; | |
2047 | ||
2048 | vma = find_vma(mm, address); | |
2049 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; | |
2050 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
2051 | if (address < hstart || address + HPAGE_PMD_SIZE > hend) | |
2052 | goto out; | |
2053 | ||
60ab3244 AA |
2054 | if ((!(vma->vm_flags & VM_HUGEPAGE) && !khugepaged_always()) || |
2055 | (vma->vm_flags & VM_NOHUGEPAGE)) | |
ba76149f AA |
2056 | goto out; |
2057 | ||
78f11a25 | 2058 | if (!vma->anon_vma || vma->vm_ops) |
ba76149f | 2059 | goto out; |
a7d6e4ec AA |
2060 | if (is_vma_temporary_stack(vma)) |
2061 | goto out; | |
b3b9c293 | 2062 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); |
ba76149f AA |
2063 | |
2064 | pgd = pgd_offset(mm, address); | |
2065 | if (!pgd_present(*pgd)) | |
2066 | goto out; | |
2067 | ||
2068 | pud = pud_offset(pgd, address); | |
2069 | if (!pud_present(*pud)) | |
2070 | goto out; | |
2071 | ||
2072 | pmd = pmd_offset(pud, address); | |
2073 | /* pmd can't go away or become huge under us */ | |
2074 | if (!pmd_present(*pmd) || pmd_trans_huge(*pmd)) | |
2075 | goto out; | |
2076 | ||
ba76149f AA |
2077 | anon_vma_lock(vma->anon_vma); |
2078 | ||
2079 | pte = pte_offset_map(pmd, address); | |
2080 | ptl = pte_lockptr(mm, pmd); | |
2081 | ||
2ec74c3e SG |
2082 | mmun_start = address; |
2083 | mmun_end = address + HPAGE_PMD_SIZE; | |
2084 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); | |
ba76149f AA |
2085 | spin_lock(&mm->page_table_lock); /* probably unnecessary */ |
2086 | /* | |
2087 | * After this gup_fast can't run anymore. This also removes | |
2088 | * any huge TLB entry from the CPU so we won't allow | |
2089 | * huge and small TLB entries for the same virtual address | |
2090 | * to avoid the risk of CPU bugs in that area. | |
2091 | */ | |
2ec74c3e | 2092 | _pmd = pmdp_clear_flush(vma, address, pmd); |
ba76149f | 2093 | spin_unlock(&mm->page_table_lock); |
2ec74c3e | 2094 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
ba76149f AA |
2095 | |
2096 | spin_lock(ptl); | |
2097 | isolated = __collapse_huge_page_isolate(vma, address, pte); | |
2098 | spin_unlock(ptl); | |
ba76149f AA |
2099 | |
2100 | if (unlikely(!isolated)) { | |
453c7192 | 2101 | pte_unmap(pte); |
ba76149f AA |
2102 | spin_lock(&mm->page_table_lock); |
2103 | BUG_ON(!pmd_none(*pmd)); | |
2104 | set_pmd_at(mm, address, pmd, _pmd); | |
2105 | spin_unlock(&mm->page_table_lock); | |
2106 | anon_vma_unlock(vma->anon_vma); | |
ce83d217 | 2107 | goto out; |
ba76149f AA |
2108 | } |
2109 | ||
2110 | /* | |
2111 | * All pages are isolated and locked so anon_vma rmap | |
2112 | * can't run anymore. | |
2113 | */ | |
2114 | anon_vma_unlock(vma->anon_vma); | |
2115 | ||
2116 | __collapse_huge_page_copy(pte, new_page, vma, address, ptl); | |
453c7192 | 2117 | pte_unmap(pte); |
ba76149f AA |
2118 | __SetPageUptodate(new_page); |
2119 | pgtable = pmd_pgtable(_pmd); | |
ba76149f AA |
2120 | |
2121 | _pmd = mk_pmd(new_page, vma->vm_page_prot); | |
2122 | _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); | |
2123 | _pmd = pmd_mkhuge(_pmd); | |
2124 | ||
2125 | /* | |
2126 | * spin_lock() below is not the equivalent of smp_wmb(), so | |
2127 | * this is needed to avoid the copy_huge_page writes to become | |
2128 | * visible after the set_pmd_at() write. | |
2129 | */ | |
2130 | smp_wmb(); | |
2131 | ||
2132 | spin_lock(&mm->page_table_lock); | |
2133 | BUG_ON(!pmd_none(*pmd)); | |
2134 | page_add_new_anon_rmap(new_page, vma, address); | |
2135 | set_pmd_at(mm, address, pmd, _pmd); | |
b113da65 | 2136 | update_mmu_cache_pmd(vma, address, pmd); |
e3ebcf64 | 2137 | pgtable_trans_huge_deposit(mm, pgtable); |
ba76149f AA |
2138 | spin_unlock(&mm->page_table_lock); |
2139 | ||
2140 | *hpage = NULL; | |
420256ef | 2141 | |
ba76149f | 2142 | khugepaged_pages_collapsed++; |
ce83d217 | 2143 | out_up_write: |
ba76149f | 2144 | up_write(&mm->mmap_sem); |
0bbbc0b3 AA |
2145 | return; |
2146 | ||
ce83d217 | 2147 | out: |
678ff896 | 2148 | mem_cgroup_uncharge_page(new_page); |
ce83d217 | 2149 | goto out_up_write; |
ba76149f AA |
2150 | } |
2151 | ||
2152 | static int khugepaged_scan_pmd(struct mm_struct *mm, | |
2153 | struct vm_area_struct *vma, | |
2154 | unsigned long address, | |
2155 | struct page **hpage) | |
2156 | { | |
2157 | pgd_t *pgd; | |
2158 | pud_t *pud; | |
2159 | pmd_t *pmd; | |
2160 | pte_t *pte, *_pte; | |
2161 | int ret = 0, referenced = 0, none = 0; | |
2162 | struct page *page; | |
2163 | unsigned long _address; | |
2164 | spinlock_t *ptl; | |
5c4b4be3 | 2165 | int node = -1; |
ba76149f AA |
2166 | |
2167 | VM_BUG_ON(address & ~HPAGE_PMD_MASK); | |
2168 | ||
2169 | pgd = pgd_offset(mm, address); | |
2170 | if (!pgd_present(*pgd)) | |
2171 | goto out; | |
2172 | ||
2173 | pud = pud_offset(pgd, address); | |
2174 | if (!pud_present(*pud)) | |
2175 | goto out; | |
2176 | ||
2177 | pmd = pmd_offset(pud, address); | |
2178 | if (!pmd_present(*pmd) || pmd_trans_huge(*pmd)) | |
2179 | goto out; | |
2180 | ||
2181 | pte = pte_offset_map_lock(mm, pmd, address, &ptl); | |
2182 | for (_address = address, _pte = pte; _pte < pte+HPAGE_PMD_NR; | |
2183 | _pte++, _address += PAGE_SIZE) { | |
2184 | pte_t pteval = *_pte; | |
2185 | if (pte_none(pteval)) { | |
2186 | if (++none <= khugepaged_max_ptes_none) | |
2187 | continue; | |
2188 | else | |
2189 | goto out_unmap; | |
2190 | } | |
2191 | if (!pte_present(pteval) || !pte_write(pteval)) | |
2192 | goto out_unmap; | |
2193 | page = vm_normal_page(vma, _address, pteval); | |
2194 | if (unlikely(!page)) | |
2195 | goto out_unmap; | |
5c4b4be3 AK |
2196 | /* |
2197 | * Chose the node of the first page. This could | |
2198 | * be more sophisticated and look at more pages, | |
2199 | * but isn't for now. | |
2200 | */ | |
2201 | if (node == -1) | |
2202 | node = page_to_nid(page); | |
ba76149f AA |
2203 | VM_BUG_ON(PageCompound(page)); |
2204 | if (!PageLRU(page) || PageLocked(page) || !PageAnon(page)) | |
2205 | goto out_unmap; | |
2206 | /* cannot use mapcount: can't collapse if there's a gup pin */ | |
2207 | if (page_count(page) != 1) | |
2208 | goto out_unmap; | |
8ee53820 AA |
2209 | if (pte_young(pteval) || PageReferenced(page) || |
2210 | mmu_notifier_test_young(vma->vm_mm, address)) | |
ba76149f AA |
2211 | referenced = 1; |
2212 | } | |
2213 | if (referenced) | |
2214 | ret = 1; | |
2215 | out_unmap: | |
2216 | pte_unmap_unlock(pte, ptl); | |
ce83d217 AA |
2217 | if (ret) |
2218 | /* collapse_huge_page will return with the mmap_sem released */ | |
5c4b4be3 | 2219 | collapse_huge_page(mm, address, hpage, vma, node); |
ba76149f AA |
2220 | out: |
2221 | return ret; | |
2222 | } | |
2223 | ||
2224 | static void collect_mm_slot(struct mm_slot *mm_slot) | |
2225 | { | |
2226 | struct mm_struct *mm = mm_slot->mm; | |
2227 | ||
b9980cdc | 2228 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2229 | |
2230 | if (khugepaged_test_exit(mm)) { | |
2231 | /* free mm_slot */ | |
2232 | hlist_del(&mm_slot->hash); | |
2233 | list_del(&mm_slot->mm_node); | |
2234 | ||
2235 | /* | |
2236 | * Not strictly needed because the mm exited already. | |
2237 | * | |
2238 | * clear_bit(MMF_VM_HUGEPAGE, &mm->flags); | |
2239 | */ | |
2240 | ||
2241 | /* khugepaged_mm_lock actually not necessary for the below */ | |
2242 | free_mm_slot(mm_slot); | |
2243 | mmdrop(mm); | |
2244 | } | |
2245 | } | |
2246 | ||
2247 | static unsigned int khugepaged_scan_mm_slot(unsigned int pages, | |
2248 | struct page **hpage) | |
2f1da642 HS |
2249 | __releases(&khugepaged_mm_lock) |
2250 | __acquires(&khugepaged_mm_lock) | |
ba76149f AA |
2251 | { |
2252 | struct mm_slot *mm_slot; | |
2253 | struct mm_struct *mm; | |
2254 | struct vm_area_struct *vma; | |
2255 | int progress = 0; | |
2256 | ||
2257 | VM_BUG_ON(!pages); | |
b9980cdc | 2258 | VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&khugepaged_mm_lock)); |
ba76149f AA |
2259 | |
2260 | if (khugepaged_scan.mm_slot) | |
2261 | mm_slot = khugepaged_scan.mm_slot; | |
2262 | else { | |
2263 | mm_slot = list_entry(khugepaged_scan.mm_head.next, | |
2264 | struct mm_slot, mm_node); | |
2265 | khugepaged_scan.address = 0; | |
2266 | khugepaged_scan.mm_slot = mm_slot; | |
2267 | } | |
2268 | spin_unlock(&khugepaged_mm_lock); | |
2269 | ||
2270 | mm = mm_slot->mm; | |
2271 | down_read(&mm->mmap_sem); | |
2272 | if (unlikely(khugepaged_test_exit(mm))) | |
2273 | vma = NULL; | |
2274 | else | |
2275 | vma = find_vma(mm, khugepaged_scan.address); | |
2276 | ||
2277 | progress++; | |
2278 | for (; vma; vma = vma->vm_next) { | |
2279 | unsigned long hstart, hend; | |
2280 | ||
2281 | cond_resched(); | |
2282 | if (unlikely(khugepaged_test_exit(mm))) { | |
2283 | progress++; | |
2284 | break; | |
2285 | } | |
2286 | ||
60ab3244 AA |
2287 | if ((!(vma->vm_flags & VM_HUGEPAGE) && |
2288 | !khugepaged_always()) || | |
2289 | (vma->vm_flags & VM_NOHUGEPAGE)) { | |
a7d6e4ec | 2290 | skip: |
ba76149f AA |
2291 | progress++; |
2292 | continue; | |
2293 | } | |
78f11a25 | 2294 | if (!vma->anon_vma || vma->vm_ops) |
a7d6e4ec AA |
2295 | goto skip; |
2296 | if (is_vma_temporary_stack(vma)) | |
2297 | goto skip; | |
b3b9c293 | 2298 | VM_BUG_ON(vma->vm_flags & VM_NO_THP); |
ba76149f AA |
2299 | |
2300 | hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; | |
2301 | hend = vma->vm_end & HPAGE_PMD_MASK; | |
a7d6e4ec AA |
2302 | if (hstart >= hend) |
2303 | goto skip; | |
2304 | if (khugepaged_scan.address > hend) | |
2305 | goto skip; | |
ba76149f AA |
2306 | if (khugepaged_scan.address < hstart) |
2307 | khugepaged_scan.address = hstart; | |
a7d6e4ec | 2308 | VM_BUG_ON(khugepaged_scan.address & ~HPAGE_PMD_MASK); |
ba76149f AA |
2309 | |
2310 | while (khugepaged_scan.address < hend) { | |
2311 | int ret; | |
2312 | cond_resched(); | |
2313 | if (unlikely(khugepaged_test_exit(mm))) | |
2314 | goto breakouterloop; | |
2315 | ||
2316 | VM_BUG_ON(khugepaged_scan.address < hstart || | |
2317 | khugepaged_scan.address + HPAGE_PMD_SIZE > | |
2318 | hend); | |
2319 | ret = khugepaged_scan_pmd(mm, vma, | |
2320 | khugepaged_scan.address, | |
2321 | hpage); | |
2322 | /* move to next address */ | |
2323 | khugepaged_scan.address += HPAGE_PMD_SIZE; | |
2324 | progress += HPAGE_PMD_NR; | |
2325 | if (ret) | |
2326 | /* we released mmap_sem so break loop */ | |
2327 | goto breakouterloop_mmap_sem; | |
2328 | if (progress >= pages) | |
2329 | goto breakouterloop; | |
2330 | } | |
2331 | } | |
2332 | breakouterloop: | |
2333 | up_read(&mm->mmap_sem); /* exit_mmap will destroy ptes after this */ | |
2334 | breakouterloop_mmap_sem: | |
2335 | ||
2336 | spin_lock(&khugepaged_mm_lock); | |
a7d6e4ec | 2337 | VM_BUG_ON(khugepaged_scan.mm_slot != mm_slot); |
ba76149f AA |
2338 | /* |
2339 | * Release the current mm_slot if this mm is about to die, or | |
2340 | * if we scanned all vmas of this mm. | |
2341 | */ | |
2342 | if (khugepaged_test_exit(mm) || !vma) { | |
2343 | /* | |
2344 | * Make sure that if mm_users is reaching zero while | |
2345 | * khugepaged runs here, khugepaged_exit will find | |
2346 | * mm_slot not pointing to the exiting mm. | |
2347 | */ | |
2348 | if (mm_slot->mm_node.next != &khugepaged_scan.mm_head) { | |
2349 | khugepaged_scan.mm_slot = list_entry( | |
2350 | mm_slot->mm_node.next, | |
2351 | struct mm_slot, mm_node); | |
2352 | khugepaged_scan.address = 0; | |
2353 | } else { | |
2354 | khugepaged_scan.mm_slot = NULL; | |
2355 | khugepaged_full_scans++; | |
2356 | } | |
2357 | ||
2358 | collect_mm_slot(mm_slot); | |
2359 | } | |
2360 | ||
2361 | return progress; | |
2362 | } | |
2363 | ||
2364 | static int khugepaged_has_work(void) | |
2365 | { | |
2366 | return !list_empty(&khugepaged_scan.mm_head) && | |
2367 | khugepaged_enabled(); | |
2368 | } | |
2369 | ||
2370 | static int khugepaged_wait_event(void) | |
2371 | { | |
2372 | return !list_empty(&khugepaged_scan.mm_head) || | |
2017c0bf | 2373 | kthread_should_stop(); |
ba76149f AA |
2374 | } |
2375 | ||
d516904b | 2376 | static void khugepaged_do_scan(void) |
ba76149f | 2377 | { |
d516904b | 2378 | struct page *hpage = NULL; |
ba76149f AA |
2379 | unsigned int progress = 0, pass_through_head = 0; |
2380 | unsigned int pages = khugepaged_pages_to_scan; | |
d516904b | 2381 | bool wait = true; |
ba76149f AA |
2382 | |
2383 | barrier(); /* write khugepaged_pages_to_scan to local stack */ | |
2384 | ||
2385 | while (progress < pages) { | |
26234f36 | 2386 | if (!khugepaged_prealloc_page(&hpage, &wait)) |
d516904b | 2387 | break; |
26234f36 | 2388 | |
420256ef | 2389 | cond_resched(); |
ba76149f | 2390 | |
878aee7d AA |
2391 | if (unlikely(kthread_should_stop() || freezing(current))) |
2392 | break; | |
2393 | ||
ba76149f AA |
2394 | spin_lock(&khugepaged_mm_lock); |
2395 | if (!khugepaged_scan.mm_slot) | |
2396 | pass_through_head++; | |
2397 | if (khugepaged_has_work() && | |
2398 | pass_through_head < 2) | |
2399 | progress += khugepaged_scan_mm_slot(pages - progress, | |
d516904b | 2400 | &hpage); |
ba76149f AA |
2401 | else |
2402 | progress = pages; | |
2403 | spin_unlock(&khugepaged_mm_lock); | |
2404 | } | |
ba76149f | 2405 | |
d516904b XG |
2406 | if (!IS_ERR_OR_NULL(hpage)) |
2407 | put_page(hpage); | |
0bbbc0b3 AA |
2408 | } |
2409 | ||
2017c0bf XG |
2410 | static void khugepaged_wait_work(void) |
2411 | { | |
2412 | try_to_freeze(); | |
2413 | ||
2414 | if (khugepaged_has_work()) { | |
2415 | if (!khugepaged_scan_sleep_millisecs) | |
2416 | return; | |
2417 | ||
2418 | wait_event_freezable_timeout(khugepaged_wait, | |
2419 | kthread_should_stop(), | |
2420 | msecs_to_jiffies(khugepaged_scan_sleep_millisecs)); | |
2421 | return; | |
2422 | } | |
2423 | ||
2424 | if (khugepaged_enabled()) | |
2425 | wait_event_freezable(khugepaged_wait, khugepaged_wait_event()); | |
2426 | } | |
2427 | ||
ba76149f AA |
2428 | static int khugepaged(void *none) |
2429 | { | |
2430 | struct mm_slot *mm_slot; | |
2431 | ||
878aee7d | 2432 | set_freezable(); |
ba76149f AA |
2433 | set_user_nice(current, 19); |
2434 | ||
b7231789 XG |
2435 | while (!kthread_should_stop()) { |
2436 | khugepaged_do_scan(); | |
2437 | khugepaged_wait_work(); | |
2438 | } | |
ba76149f AA |
2439 | |
2440 | spin_lock(&khugepaged_mm_lock); | |
2441 | mm_slot = khugepaged_scan.mm_slot; | |
2442 | khugepaged_scan.mm_slot = NULL; | |
2443 | if (mm_slot) | |
2444 | collect_mm_slot(mm_slot); | |
2445 | spin_unlock(&khugepaged_mm_lock); | |
ba76149f AA |
2446 | return 0; |
2447 | } | |
2448 | ||
71e3aac0 AA |
2449 | void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd) |
2450 | { | |
2451 | struct page *page; | |
2452 | ||
2453 | spin_lock(&mm->page_table_lock); | |
2454 | if (unlikely(!pmd_trans_huge(*pmd))) { | |
2455 | spin_unlock(&mm->page_table_lock); | |
2456 | return; | |
2457 | } | |
2458 | page = pmd_page(*pmd); | |
2459 | VM_BUG_ON(!page_count(page)); | |
2460 | get_page(page); | |
2461 | spin_unlock(&mm->page_table_lock); | |
2462 | ||
2463 | split_huge_page(page); | |
2464 | ||
2465 | put_page(page); | |
2466 | BUG_ON(pmd_trans_huge(*pmd)); | |
2467 | } | |
94fcc585 AA |
2468 | |
2469 | static void split_huge_page_address(struct mm_struct *mm, | |
2470 | unsigned long address) | |
2471 | { | |
2472 | pgd_t *pgd; | |
2473 | pud_t *pud; | |
2474 | pmd_t *pmd; | |
2475 | ||
2476 | VM_BUG_ON(!(address & ~HPAGE_PMD_MASK)); | |
2477 | ||
2478 | pgd = pgd_offset(mm, address); | |
2479 | if (!pgd_present(*pgd)) | |
2480 | return; | |
2481 | ||
2482 | pud = pud_offset(pgd, address); | |
2483 | if (!pud_present(*pud)) | |
2484 | return; | |
2485 | ||
2486 | pmd = pmd_offset(pud, address); | |
2487 | if (!pmd_present(*pmd)) | |
2488 | return; | |
2489 | /* | |
2490 | * Caller holds the mmap_sem write mode, so a huge pmd cannot | |
2491 | * materialize from under us. | |
2492 | */ | |
2493 | split_huge_page_pmd(mm, pmd); | |
2494 | } | |
2495 | ||
2496 | void __vma_adjust_trans_huge(struct vm_area_struct *vma, | |
2497 | unsigned long start, | |
2498 | unsigned long end, | |
2499 | long adjust_next) | |
2500 | { | |
2501 | /* | |
2502 | * If the new start address isn't hpage aligned and it could | |
2503 | * previously contain an hugepage: check if we need to split | |
2504 | * an huge pmd. | |
2505 | */ | |
2506 | if (start & ~HPAGE_PMD_MASK && | |
2507 | (start & HPAGE_PMD_MASK) >= vma->vm_start && | |
2508 | (start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2509 | split_huge_page_address(vma->vm_mm, start); | |
2510 | ||
2511 | /* | |
2512 | * If the new end address isn't hpage aligned and it could | |
2513 | * previously contain an hugepage: check if we need to split | |
2514 | * an huge pmd. | |
2515 | */ | |
2516 | if (end & ~HPAGE_PMD_MASK && | |
2517 | (end & HPAGE_PMD_MASK) >= vma->vm_start && | |
2518 | (end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end) | |
2519 | split_huge_page_address(vma->vm_mm, end); | |
2520 | ||
2521 | /* | |
2522 | * If we're also updating the vma->vm_next->vm_start, if the new | |
2523 | * vm_next->vm_start isn't page aligned and it could previously | |
2524 | * contain an hugepage: check if we need to split an huge pmd. | |
2525 | */ | |
2526 | if (adjust_next > 0) { | |
2527 | struct vm_area_struct *next = vma->vm_next; | |
2528 | unsigned long nstart = next->vm_start; | |
2529 | nstart += adjust_next << PAGE_SHIFT; | |
2530 | if (nstart & ~HPAGE_PMD_MASK && | |
2531 | (nstart & HPAGE_PMD_MASK) >= next->vm_start && | |
2532 | (nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end) | |
2533 | split_huge_page_address(next->vm_mm, nstart); | |
2534 | } | |
2535 | } |