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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | #include <linux/debugfs.h> | |
3 | #include <linux/mm.h> | |
4 | #include <linux/slab.h> | |
5 | #include <linux/uaccess.h> | |
6 | #include <linux/memblock.h> | |
7 | #include <linux/stacktrace.h> | |
8 | #include <linux/page_owner.h> | |
9 | #include <linux/jump_label.h> | |
10 | #include <linux/migrate.h> | |
11 | #include <linux/stackdepot.h> | |
12 | #include <linux/seq_file.h> | |
13 | ||
14 | #include "internal.h" | |
15 | ||
16 | /* | |
17 | * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack) | |
18 | * to use off stack temporal storage | |
19 | */ | |
20 | #define PAGE_OWNER_STACK_DEPTH (16) | |
21 | ||
22 | struct page_owner { | |
23 | unsigned short order; | |
24 | short last_migrate_reason; | |
25 | gfp_t gfp_mask; | |
26 | depot_stack_handle_t handle; | |
27 | }; | |
28 | ||
29 | static bool page_owner_disabled = true; | |
30 | DEFINE_STATIC_KEY_FALSE(page_owner_inited); | |
31 | ||
32 | static depot_stack_handle_t dummy_handle; | |
33 | static depot_stack_handle_t failure_handle; | |
34 | static depot_stack_handle_t early_handle; | |
35 | ||
36 | static void init_early_allocated_pages(void); | |
37 | ||
38 | static int __init early_page_owner_param(char *buf) | |
39 | { | |
40 | if (!buf) | |
41 | return -EINVAL; | |
42 | ||
43 | if (strcmp(buf, "on") == 0) | |
44 | page_owner_disabled = false; | |
45 | ||
46 | return 0; | |
47 | } | |
48 | early_param("page_owner", early_page_owner_param); | |
49 | ||
50 | static bool need_page_owner(void) | |
51 | { | |
52 | if (page_owner_disabled) | |
53 | return false; | |
54 | ||
55 | return true; | |
56 | } | |
57 | ||
58 | static __always_inline depot_stack_handle_t create_dummy_stack(void) | |
59 | { | |
60 | unsigned long entries[4]; | |
61 | unsigned int nr_entries; | |
62 | ||
63 | nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0); | |
64 | return stack_depot_save(entries, nr_entries, GFP_KERNEL); | |
65 | } | |
66 | ||
67 | static noinline void register_dummy_stack(void) | |
68 | { | |
69 | dummy_handle = create_dummy_stack(); | |
70 | } | |
71 | ||
72 | static noinline void register_failure_stack(void) | |
73 | { | |
74 | failure_handle = create_dummy_stack(); | |
75 | } | |
76 | ||
77 | static noinline void register_early_stack(void) | |
78 | { | |
79 | early_handle = create_dummy_stack(); | |
80 | } | |
81 | ||
82 | static void init_page_owner(void) | |
83 | { | |
84 | if (page_owner_disabled) | |
85 | return; | |
86 | ||
87 | register_dummy_stack(); | |
88 | register_failure_stack(); | |
89 | register_early_stack(); | |
90 | static_branch_enable(&page_owner_inited); | |
91 | init_early_allocated_pages(); | |
92 | } | |
93 | ||
94 | struct page_ext_operations page_owner_ops = { | |
95 | .size = sizeof(struct page_owner), | |
96 | .need = need_page_owner, | |
97 | .init = init_page_owner, | |
98 | }; | |
99 | ||
100 | static inline struct page_owner *get_page_owner(struct page_ext *page_ext) | |
101 | { | |
102 | return (void *)page_ext + page_owner_ops.offset; | |
103 | } | |
104 | ||
105 | void __reset_page_owner(struct page *page, unsigned int order) | |
106 | { | |
107 | int i; | |
108 | struct page_ext *page_ext; | |
109 | ||
110 | for (i = 0; i < (1 << order); i++) { | |
111 | page_ext = lookup_page_ext(page + i); | |
112 | if (unlikely(!page_ext)) | |
113 | continue; | |
114 | __clear_bit(PAGE_EXT_OWNER, &page_ext->flags); | |
115 | } | |
116 | } | |
117 | ||
118 | static inline bool check_recursive_alloc(unsigned long *entries, | |
119 | unsigned int nr_entries, | |
120 | unsigned long ip) | |
121 | { | |
122 | unsigned int i; | |
123 | ||
124 | for (i = 0; i < nr_entries; i++) { | |
125 | if (entries[i] == ip) | |
126 | return true; | |
127 | } | |
128 | return false; | |
129 | } | |
130 | ||
131 | static noinline depot_stack_handle_t save_stack(gfp_t flags) | |
132 | { | |
133 | unsigned long entries[PAGE_OWNER_STACK_DEPTH]; | |
134 | depot_stack_handle_t handle; | |
135 | unsigned int nr_entries; | |
136 | ||
137 | nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2); | |
138 | ||
139 | /* | |
140 | * We need to check recursion here because our request to | |
141 | * stackdepot could trigger memory allocation to save new | |
142 | * entry. New memory allocation would reach here and call | |
143 | * stack_depot_save_entries() again if we don't catch it. There is | |
144 | * still not enough memory in stackdepot so it would try to | |
145 | * allocate memory again and loop forever. | |
146 | */ | |
147 | if (check_recursive_alloc(entries, nr_entries, _RET_IP_)) | |
148 | return dummy_handle; | |
149 | ||
150 | handle = stack_depot_save(entries, nr_entries, flags); | |
151 | if (!handle) | |
152 | handle = failure_handle; | |
153 | ||
154 | return handle; | |
155 | } | |
156 | ||
157 | static inline void __set_page_owner_handle(struct page_ext *page_ext, | |
158 | depot_stack_handle_t handle, unsigned int order, gfp_t gfp_mask) | |
159 | { | |
160 | struct page_owner *page_owner; | |
161 | ||
162 | page_owner = get_page_owner(page_ext); | |
163 | page_owner->handle = handle; | |
164 | page_owner->order = order; | |
165 | page_owner->gfp_mask = gfp_mask; | |
166 | page_owner->last_migrate_reason = -1; | |
167 | ||
168 | __set_bit(PAGE_EXT_OWNER, &page_ext->flags); | |
169 | } | |
170 | ||
171 | noinline void __set_page_owner(struct page *page, unsigned int order, | |
172 | gfp_t gfp_mask) | |
173 | { | |
174 | struct page_ext *page_ext = lookup_page_ext(page); | |
175 | depot_stack_handle_t handle; | |
176 | ||
177 | if (unlikely(!page_ext)) | |
178 | return; | |
179 | ||
180 | handle = save_stack(gfp_mask); | |
181 | __set_page_owner_handle(page_ext, handle, order, gfp_mask); | |
182 | } | |
183 | ||
184 | void __set_page_owner_migrate_reason(struct page *page, int reason) | |
185 | { | |
186 | struct page_ext *page_ext = lookup_page_ext(page); | |
187 | struct page_owner *page_owner; | |
188 | ||
189 | if (unlikely(!page_ext)) | |
190 | return; | |
191 | ||
192 | page_owner = get_page_owner(page_ext); | |
193 | page_owner->last_migrate_reason = reason; | |
194 | } | |
195 | ||
196 | void __split_page_owner(struct page *page, unsigned int order) | |
197 | { | |
198 | int i; | |
199 | struct page_ext *page_ext = lookup_page_ext(page); | |
200 | struct page_owner *page_owner; | |
201 | ||
202 | if (unlikely(!page_ext)) | |
203 | return; | |
204 | ||
205 | page_owner = get_page_owner(page_ext); | |
206 | page_owner->order = 0; | |
207 | for (i = 1; i < (1 << order); i++) | |
208 | __copy_page_owner(page, page + i); | |
209 | } | |
210 | ||
211 | void __copy_page_owner(struct page *oldpage, struct page *newpage) | |
212 | { | |
213 | struct page_ext *old_ext = lookup_page_ext(oldpage); | |
214 | struct page_ext *new_ext = lookup_page_ext(newpage); | |
215 | struct page_owner *old_page_owner, *new_page_owner; | |
216 | ||
217 | if (unlikely(!old_ext || !new_ext)) | |
218 | return; | |
219 | ||
220 | old_page_owner = get_page_owner(old_ext); | |
221 | new_page_owner = get_page_owner(new_ext); | |
222 | new_page_owner->order = old_page_owner->order; | |
223 | new_page_owner->gfp_mask = old_page_owner->gfp_mask; | |
224 | new_page_owner->last_migrate_reason = | |
225 | old_page_owner->last_migrate_reason; | |
226 | new_page_owner->handle = old_page_owner->handle; | |
227 | ||
228 | /* | |
229 | * We don't clear the bit on the oldpage as it's going to be freed | |
230 | * after migration. Until then, the info can be useful in case of | |
231 | * a bug, and the overal stats will be off a bit only temporarily. | |
232 | * Also, migrate_misplaced_transhuge_page() can still fail the | |
233 | * migration and then we want the oldpage to retain the info. But | |
234 | * in that case we also don't need to explicitly clear the info from | |
235 | * the new page, which will be freed. | |
236 | */ | |
237 | __set_bit(PAGE_EXT_OWNER, &new_ext->flags); | |
238 | } | |
239 | ||
240 | void pagetypeinfo_showmixedcount_print(struct seq_file *m, | |
241 | pg_data_t *pgdat, struct zone *zone) | |
242 | { | |
243 | struct page *page; | |
244 | struct page_ext *page_ext; | |
245 | struct page_owner *page_owner; | |
246 | unsigned long pfn = zone->zone_start_pfn, block_end_pfn; | |
247 | unsigned long end_pfn = pfn + zone->spanned_pages; | |
248 | unsigned long count[MIGRATE_TYPES] = { 0, }; | |
249 | int pageblock_mt, page_mt; | |
250 | int i; | |
251 | ||
252 | /* Scan block by block. First and last block may be incomplete */ | |
253 | pfn = zone->zone_start_pfn; | |
254 | ||
255 | /* | |
256 | * Walk the zone in pageblock_nr_pages steps. If a page block spans | |
257 | * a zone boundary, it will be double counted between zones. This does | |
258 | * not matter as the mixed block count will still be correct | |
259 | */ | |
260 | for (; pfn < end_pfn; ) { | |
261 | if (!pfn_valid(pfn)) { | |
262 | pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); | |
263 | continue; | |
264 | } | |
265 | ||
266 | block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); | |
267 | block_end_pfn = min(block_end_pfn, end_pfn); | |
268 | ||
269 | page = pfn_to_page(pfn); | |
270 | pageblock_mt = get_pageblock_migratetype(page); | |
271 | ||
272 | for (; pfn < block_end_pfn; pfn++) { | |
273 | if (!pfn_valid_within(pfn)) | |
274 | continue; | |
275 | ||
276 | page = pfn_to_page(pfn); | |
277 | ||
278 | if (page_zone(page) != zone) | |
279 | continue; | |
280 | ||
281 | if (PageBuddy(page)) { | |
282 | unsigned long freepage_order; | |
283 | ||
284 | freepage_order = page_order_unsafe(page); | |
285 | if (freepage_order < MAX_ORDER) | |
286 | pfn += (1UL << freepage_order) - 1; | |
287 | continue; | |
288 | } | |
289 | ||
290 | if (PageReserved(page)) | |
291 | continue; | |
292 | ||
293 | page_ext = lookup_page_ext(page); | |
294 | if (unlikely(!page_ext)) | |
295 | continue; | |
296 | ||
297 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) | |
298 | continue; | |
299 | ||
300 | page_owner = get_page_owner(page_ext); | |
301 | page_mt = gfpflags_to_migratetype( | |
302 | page_owner->gfp_mask); | |
303 | if (pageblock_mt != page_mt) { | |
304 | if (is_migrate_cma(pageblock_mt)) | |
305 | count[MIGRATE_MOVABLE]++; | |
306 | else | |
307 | count[pageblock_mt]++; | |
308 | ||
309 | pfn = block_end_pfn; | |
310 | break; | |
311 | } | |
312 | pfn += (1UL << page_owner->order) - 1; | |
313 | } | |
314 | } | |
315 | ||
316 | /* Print counts */ | |
317 | seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name); | |
318 | for (i = 0; i < MIGRATE_TYPES; i++) | |
319 | seq_printf(m, "%12lu ", count[i]); | |
320 | seq_putc(m, '\n'); | |
321 | } | |
322 | ||
323 | static ssize_t | |
324 | print_page_owner(char __user *buf, size_t count, unsigned long pfn, | |
325 | struct page *page, struct page_owner *page_owner, | |
326 | depot_stack_handle_t handle) | |
327 | { | |
328 | int ret, pageblock_mt, page_mt; | |
329 | unsigned long *entries; | |
330 | unsigned int nr_entries; | |
331 | char *kbuf; | |
332 | ||
333 | count = min_t(size_t, count, PAGE_SIZE); | |
334 | kbuf = kmalloc(count, GFP_KERNEL); | |
335 | if (!kbuf) | |
336 | return -ENOMEM; | |
337 | ||
338 | ret = snprintf(kbuf, count, | |
339 | "Page allocated via order %u, mask %#x(%pGg)\n", | |
340 | page_owner->order, page_owner->gfp_mask, | |
341 | &page_owner->gfp_mask); | |
342 | ||
343 | if (ret >= count) | |
344 | goto err; | |
345 | ||
346 | /* Print information relevant to grouping pages by mobility */ | |
347 | pageblock_mt = get_pageblock_migratetype(page); | |
348 | page_mt = gfpflags_to_migratetype(page_owner->gfp_mask); | |
349 | ret += snprintf(kbuf + ret, count - ret, | |
350 | "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n", | |
351 | pfn, | |
352 | migratetype_names[page_mt], | |
353 | pfn >> pageblock_order, | |
354 | migratetype_names[pageblock_mt], | |
355 | page->flags, &page->flags); | |
356 | ||
357 | if (ret >= count) | |
358 | goto err; | |
359 | ||
360 | nr_entries = stack_depot_fetch(handle, &entries); | |
361 | ret += stack_trace_snprint(kbuf + ret, count - ret, entries, nr_entries, 0); | |
362 | if (ret >= count) | |
363 | goto err; | |
364 | ||
365 | if (page_owner->last_migrate_reason != -1) { | |
366 | ret += snprintf(kbuf + ret, count - ret, | |
367 | "Page has been migrated, last migrate reason: %s\n", | |
368 | migrate_reason_names[page_owner->last_migrate_reason]); | |
369 | if (ret >= count) | |
370 | goto err; | |
371 | } | |
372 | ||
373 | ret += snprintf(kbuf + ret, count - ret, "\n"); | |
374 | if (ret >= count) | |
375 | goto err; | |
376 | ||
377 | if (copy_to_user(buf, kbuf, ret)) | |
378 | ret = -EFAULT; | |
379 | ||
380 | kfree(kbuf); | |
381 | return ret; | |
382 | ||
383 | err: | |
384 | kfree(kbuf); | |
385 | return -ENOMEM; | |
386 | } | |
387 | ||
388 | void __dump_page_owner(struct page *page) | |
389 | { | |
390 | struct page_ext *page_ext = lookup_page_ext(page); | |
391 | struct page_owner *page_owner; | |
392 | depot_stack_handle_t handle; | |
393 | unsigned long *entries; | |
394 | unsigned int nr_entries; | |
395 | gfp_t gfp_mask; | |
396 | int mt; | |
397 | ||
398 | if (unlikely(!page_ext)) { | |
399 | pr_alert("There is not page extension available.\n"); | |
400 | return; | |
401 | } | |
402 | ||
403 | page_owner = get_page_owner(page_ext); | |
404 | gfp_mask = page_owner->gfp_mask; | |
405 | mt = gfpflags_to_migratetype(gfp_mask); | |
406 | ||
407 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) { | |
408 | pr_alert("page_owner info is not active (free page?)\n"); | |
409 | return; | |
410 | } | |
411 | ||
412 | handle = READ_ONCE(page_owner->handle); | |
413 | if (!handle) { | |
414 | pr_alert("page_owner info is not active (free page?)\n"); | |
415 | return; | |
416 | } | |
417 | ||
418 | nr_entries = stack_depot_fetch(handle, &entries); | |
419 | pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n", | |
420 | page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask); | |
421 | stack_trace_print(entries, nr_entries, 0); | |
422 | ||
423 | if (page_owner->last_migrate_reason != -1) | |
424 | pr_alert("page has been migrated, last migrate reason: %s\n", | |
425 | migrate_reason_names[page_owner->last_migrate_reason]); | |
426 | } | |
427 | ||
428 | static ssize_t | |
429 | read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
430 | { | |
431 | unsigned long pfn; | |
432 | struct page *page; | |
433 | struct page_ext *page_ext; | |
434 | struct page_owner *page_owner; | |
435 | depot_stack_handle_t handle; | |
436 | ||
437 | if (!static_branch_unlikely(&page_owner_inited)) | |
438 | return -EINVAL; | |
439 | ||
440 | page = NULL; | |
441 | pfn = min_low_pfn + *ppos; | |
442 | ||
443 | /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ | |
444 | while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) | |
445 | pfn++; | |
446 | ||
447 | drain_all_pages(NULL); | |
448 | ||
449 | /* Find an allocated page */ | |
450 | for (; pfn < max_pfn; pfn++) { | |
451 | /* | |
452 | * If the new page is in a new MAX_ORDER_NR_PAGES area, | |
453 | * validate the area as existing, skip it if not | |
454 | */ | |
455 | if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) { | |
456 | pfn += MAX_ORDER_NR_PAGES - 1; | |
457 | continue; | |
458 | } | |
459 | ||
460 | /* Check for holes within a MAX_ORDER area */ | |
461 | if (!pfn_valid_within(pfn)) | |
462 | continue; | |
463 | ||
464 | page = pfn_to_page(pfn); | |
465 | if (PageBuddy(page)) { | |
466 | unsigned long freepage_order = page_order_unsafe(page); | |
467 | ||
468 | if (freepage_order < MAX_ORDER) | |
469 | pfn += (1UL << freepage_order) - 1; | |
470 | continue; | |
471 | } | |
472 | ||
473 | page_ext = lookup_page_ext(page); | |
474 | if (unlikely(!page_ext)) | |
475 | continue; | |
476 | ||
477 | /* | |
478 | * Some pages could be missed by concurrent allocation or free, | |
479 | * because we don't hold the zone lock. | |
480 | */ | |
481 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) | |
482 | continue; | |
483 | ||
484 | page_owner = get_page_owner(page_ext); | |
485 | ||
486 | /* | |
487 | * Access to page_ext->handle isn't synchronous so we should | |
488 | * be careful to access it. | |
489 | */ | |
490 | handle = READ_ONCE(page_owner->handle); | |
491 | if (!handle) | |
492 | continue; | |
493 | ||
494 | /* Record the next PFN to read in the file offset */ | |
495 | *ppos = (pfn - min_low_pfn) + 1; | |
496 | ||
497 | return print_page_owner(buf, count, pfn, page, | |
498 | page_owner, handle); | |
499 | } | |
500 | ||
501 | return 0; | |
502 | } | |
503 | ||
504 | static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) | |
505 | { | |
506 | unsigned long pfn = zone->zone_start_pfn; | |
507 | unsigned long end_pfn = zone_end_pfn(zone); | |
508 | unsigned long count = 0; | |
509 | ||
510 | /* | |
511 | * Walk the zone in pageblock_nr_pages steps. If a page block spans | |
512 | * a zone boundary, it will be double counted between zones. This does | |
513 | * not matter as the mixed block count will still be correct | |
514 | */ | |
515 | for (; pfn < end_pfn; ) { | |
516 | unsigned long block_end_pfn; | |
517 | ||
518 | if (!pfn_valid(pfn)) { | |
519 | pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); | |
520 | continue; | |
521 | } | |
522 | ||
523 | block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); | |
524 | block_end_pfn = min(block_end_pfn, end_pfn); | |
525 | ||
526 | for (; pfn < block_end_pfn; pfn++) { | |
527 | struct page *page; | |
528 | struct page_ext *page_ext; | |
529 | ||
530 | if (!pfn_valid_within(pfn)) | |
531 | continue; | |
532 | ||
533 | page = pfn_to_page(pfn); | |
534 | ||
535 | if (page_zone(page) != zone) | |
536 | continue; | |
537 | ||
538 | /* | |
539 | * To avoid having to grab zone->lock, be a little | |
540 | * careful when reading buddy page order. The only | |
541 | * danger is that we skip too much and potentially miss | |
542 | * some early allocated pages, which is better than | |
543 | * heavy lock contention. | |
544 | */ | |
545 | if (PageBuddy(page)) { | |
546 | unsigned long order = page_order_unsafe(page); | |
547 | ||
548 | if (order > 0 && order < MAX_ORDER) | |
549 | pfn += (1UL << order) - 1; | |
550 | continue; | |
551 | } | |
552 | ||
553 | if (PageReserved(page)) | |
554 | continue; | |
555 | ||
556 | page_ext = lookup_page_ext(page); | |
557 | if (unlikely(!page_ext)) | |
558 | continue; | |
559 | ||
560 | /* Maybe overlapping zone */ | |
561 | if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) | |
562 | continue; | |
563 | ||
564 | /* Found early allocated page */ | |
565 | __set_page_owner_handle(page_ext, early_handle, 0, 0); | |
566 | count++; | |
567 | } | |
568 | cond_resched(); | |
569 | } | |
570 | ||
571 | pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n", | |
572 | pgdat->node_id, zone->name, count); | |
573 | } | |
574 | ||
575 | static void init_zones_in_node(pg_data_t *pgdat) | |
576 | { | |
577 | struct zone *zone; | |
578 | struct zone *node_zones = pgdat->node_zones; | |
579 | ||
580 | for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { | |
581 | if (!populated_zone(zone)) | |
582 | continue; | |
583 | ||
584 | init_pages_in_zone(pgdat, zone); | |
585 | } | |
586 | } | |
587 | ||
588 | static void init_early_allocated_pages(void) | |
589 | { | |
590 | pg_data_t *pgdat; | |
591 | ||
592 | for_each_online_pgdat(pgdat) | |
593 | init_zones_in_node(pgdat); | |
594 | } | |
595 | ||
596 | static const struct file_operations proc_page_owner_operations = { | |
597 | .read = read_page_owner, | |
598 | }; | |
599 | ||
600 | static int __init pageowner_init(void) | |
601 | { | |
602 | if (!static_branch_unlikely(&page_owner_inited)) { | |
603 | pr_info("page_owner is disabled\n"); | |
604 | return 0; | |
605 | } | |
606 | ||
607 | debugfs_create_file("page_owner", 0400, NULL, NULL, | |
608 | &proc_page_owner_operations); | |
609 | ||
610 | return 0; | |
611 | } | |
612 | late_initcall(pageowner_init) |