Commit | Line | Data |
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48c96a36 JK |
1 | #include <linux/debugfs.h> |
2 | #include <linux/mm.h> | |
3 | #include <linux/slab.h> | |
4 | #include <linux/uaccess.h> | |
5 | #include <linux/bootmem.h> | |
6 | #include <linux/stacktrace.h> | |
7 | #include <linux/page_owner.h> | |
7dd80b8a | 8 | #include <linux/jump_label.h> |
7cd12b4a | 9 | #include <linux/migrate.h> |
f2ca0b55 JK |
10 | #include <linux/stackdepot.h> |
11 | ||
48c96a36 JK |
12 | #include "internal.h" |
13 | ||
f2ca0b55 JK |
14 | /* |
15 | * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack) | |
16 | * to use off stack temporal storage | |
17 | */ | |
18 | #define PAGE_OWNER_STACK_DEPTH (16) | |
19 | ||
48c96a36 | 20 | static bool page_owner_disabled = true; |
7dd80b8a | 21 | DEFINE_STATIC_KEY_FALSE(page_owner_inited); |
48c96a36 | 22 | |
f2ca0b55 JK |
23 | static depot_stack_handle_t dummy_handle; |
24 | static depot_stack_handle_t failure_handle; | |
25 | ||
61cf5feb JK |
26 | static void init_early_allocated_pages(void); |
27 | ||
48c96a36 JK |
28 | static int early_page_owner_param(char *buf) |
29 | { | |
30 | if (!buf) | |
31 | return -EINVAL; | |
32 | ||
33 | if (strcmp(buf, "on") == 0) | |
34 | page_owner_disabled = false; | |
35 | ||
36 | return 0; | |
37 | } | |
38 | early_param("page_owner", early_page_owner_param); | |
39 | ||
40 | static bool need_page_owner(void) | |
41 | { | |
42 | if (page_owner_disabled) | |
43 | return false; | |
44 | ||
45 | return true; | |
46 | } | |
47 | ||
f2ca0b55 JK |
48 | static noinline void register_dummy_stack(void) |
49 | { | |
50 | unsigned long entries[4]; | |
51 | struct stack_trace dummy; | |
52 | ||
53 | dummy.nr_entries = 0; | |
54 | dummy.max_entries = ARRAY_SIZE(entries); | |
55 | dummy.entries = &entries[0]; | |
56 | dummy.skip = 0; | |
57 | ||
58 | save_stack_trace(&dummy); | |
59 | dummy_handle = depot_save_stack(&dummy, GFP_KERNEL); | |
60 | } | |
61 | ||
62 | static noinline void register_failure_stack(void) | |
63 | { | |
64 | unsigned long entries[4]; | |
65 | struct stack_trace failure; | |
66 | ||
67 | failure.nr_entries = 0; | |
68 | failure.max_entries = ARRAY_SIZE(entries); | |
69 | failure.entries = &entries[0]; | |
70 | failure.skip = 0; | |
71 | ||
72 | save_stack_trace(&failure); | |
73 | failure_handle = depot_save_stack(&failure, GFP_KERNEL); | |
74 | } | |
75 | ||
48c96a36 JK |
76 | static void init_page_owner(void) |
77 | { | |
78 | if (page_owner_disabled) | |
79 | return; | |
80 | ||
f2ca0b55 JK |
81 | register_dummy_stack(); |
82 | register_failure_stack(); | |
7dd80b8a | 83 | static_branch_enable(&page_owner_inited); |
61cf5feb | 84 | init_early_allocated_pages(); |
48c96a36 JK |
85 | } |
86 | ||
87 | struct page_ext_operations page_owner_ops = { | |
88 | .need = need_page_owner, | |
89 | .init = init_page_owner, | |
90 | }; | |
91 | ||
92 | void __reset_page_owner(struct page *page, unsigned int order) | |
93 | { | |
94 | int i; | |
95 | struct page_ext *page_ext; | |
96 | ||
97 | for (i = 0; i < (1 << order); i++) { | |
98 | page_ext = lookup_page_ext(page + i); | |
f86e4271 YS |
99 | if (unlikely(!page_ext)) |
100 | continue; | |
48c96a36 JK |
101 | __clear_bit(PAGE_EXT_OWNER, &page_ext->flags); |
102 | } | |
103 | } | |
104 | ||
f2ca0b55 JK |
105 | static inline bool check_recursive_alloc(struct stack_trace *trace, |
106 | unsigned long ip) | |
48c96a36 | 107 | { |
f2ca0b55 JK |
108 | int i, count; |
109 | ||
110 | if (!trace->nr_entries) | |
111 | return false; | |
112 | ||
113 | for (i = 0, count = 0; i < trace->nr_entries; i++) { | |
114 | if (trace->entries[i] == ip && ++count == 2) | |
115 | return true; | |
116 | } | |
f86e4271 | 117 | |
f2ca0b55 JK |
118 | return false; |
119 | } | |
120 | ||
121 | static noinline depot_stack_handle_t save_stack(gfp_t flags) | |
122 | { | |
123 | unsigned long entries[PAGE_OWNER_STACK_DEPTH]; | |
94f759d6 SR |
124 | struct stack_trace trace = { |
125 | .nr_entries = 0, | |
f2ca0b55 JK |
126 | .entries = entries, |
127 | .max_entries = PAGE_OWNER_STACK_DEPTH, | |
128 | .skip = 0 | |
94f759d6 | 129 | }; |
f2ca0b55 JK |
130 | depot_stack_handle_t handle; |
131 | ||
132 | save_stack_trace(&trace); | |
133 | if (trace.nr_entries != 0 && | |
134 | trace.entries[trace.nr_entries-1] == ULONG_MAX) | |
135 | trace.nr_entries--; | |
136 | ||
137 | /* | |
138 | * We need to check recursion here because our request to stackdepot | |
139 | * could trigger memory allocation to save new entry. New memory | |
140 | * allocation would reach here and call depot_save_stack() again | |
141 | * if we don't catch it. There is still not enough memory in stackdepot | |
142 | * so it would try to allocate memory again and loop forever. | |
143 | */ | |
144 | if (check_recursive_alloc(&trace, _RET_IP_)) | |
145 | return dummy_handle; | |
146 | ||
147 | handle = depot_save_stack(&trace, flags); | |
148 | if (!handle) | |
149 | handle = failure_handle; | |
150 | ||
151 | return handle; | |
152 | } | |
153 | ||
154 | noinline void __set_page_owner(struct page *page, unsigned int order, | |
155 | gfp_t gfp_mask) | |
156 | { | |
157 | struct page_ext *page_ext = lookup_page_ext(page); | |
48c96a36 | 158 | |
f86e4271 YS |
159 | if (unlikely(!page_ext)) |
160 | return; | |
161 | ||
f2ca0b55 | 162 | page_ext->handle = save_stack(gfp_mask); |
48c96a36 JK |
163 | page_ext->order = order; |
164 | page_ext->gfp_mask = gfp_mask; | |
7cd12b4a | 165 | page_ext->last_migrate_reason = -1; |
48c96a36 JK |
166 | |
167 | __set_bit(PAGE_EXT_OWNER, &page_ext->flags); | |
168 | } | |
169 | ||
7cd12b4a VB |
170 | void __set_page_owner_migrate_reason(struct page *page, int reason) |
171 | { | |
172 | struct page_ext *page_ext = lookup_page_ext(page); | |
f86e4271 YS |
173 | if (unlikely(!page_ext)) |
174 | return; | |
7cd12b4a VB |
175 | |
176 | page_ext->last_migrate_reason = reason; | |
177 | } | |
178 | ||
a9627bc5 | 179 | void __split_page_owner(struct page *page, unsigned int order) |
e2cfc911 | 180 | { |
a9627bc5 | 181 | int i; |
e2cfc911 | 182 | struct page_ext *page_ext = lookup_page_ext(page); |
a9627bc5 | 183 | |
f86e4271 | 184 | if (unlikely(!page_ext)) |
a9627bc5 | 185 | return; |
e2cfc911 | 186 | |
a9627bc5 JK |
187 | page_ext->order = 0; |
188 | for (i = 1; i < (1 << order); i++) | |
189 | __copy_page_owner(page, page + i); | |
e2cfc911 JK |
190 | } |
191 | ||
d435edca VB |
192 | void __copy_page_owner(struct page *oldpage, struct page *newpage) |
193 | { | |
194 | struct page_ext *old_ext = lookup_page_ext(oldpage); | |
195 | struct page_ext *new_ext = lookup_page_ext(newpage); | |
d435edca | 196 | |
f86e4271 YS |
197 | if (unlikely(!old_ext || !new_ext)) |
198 | return; | |
199 | ||
d435edca VB |
200 | new_ext->order = old_ext->order; |
201 | new_ext->gfp_mask = old_ext->gfp_mask; | |
a8efe1c9 | 202 | new_ext->last_migrate_reason = old_ext->last_migrate_reason; |
f2ca0b55 | 203 | new_ext->handle = old_ext->handle; |
d435edca VB |
204 | |
205 | /* | |
206 | * We don't clear the bit on the oldpage as it's going to be freed | |
207 | * after migration. Until then, the info can be useful in case of | |
208 | * a bug, and the overal stats will be off a bit only temporarily. | |
209 | * Also, migrate_misplaced_transhuge_page() can still fail the | |
210 | * migration and then we want the oldpage to retain the info. But | |
211 | * in that case we also don't need to explicitly clear the info from | |
212 | * the new page, which will be freed. | |
213 | */ | |
214 | __set_bit(PAGE_EXT_OWNER, &new_ext->flags); | |
215 | } | |
216 | ||
48c96a36 JK |
217 | static ssize_t |
218 | print_page_owner(char __user *buf, size_t count, unsigned long pfn, | |
f2ca0b55 JK |
219 | struct page *page, struct page_ext *page_ext, |
220 | depot_stack_handle_t handle) | |
48c96a36 JK |
221 | { |
222 | int ret; | |
223 | int pageblock_mt, page_mt; | |
224 | char *kbuf; | |
f2ca0b55 | 225 | unsigned long entries[PAGE_OWNER_STACK_DEPTH]; |
94f759d6 | 226 | struct stack_trace trace = { |
f2ca0b55 JK |
227 | .nr_entries = 0, |
228 | .entries = entries, | |
229 | .max_entries = PAGE_OWNER_STACK_DEPTH, | |
230 | .skip = 0 | |
94f759d6 | 231 | }; |
48c96a36 JK |
232 | |
233 | kbuf = kmalloc(count, GFP_KERNEL); | |
234 | if (!kbuf) | |
235 | return -ENOMEM; | |
236 | ||
237 | ret = snprintf(kbuf, count, | |
60f30350 VB |
238 | "Page allocated via order %u, mask %#x(%pGg)\n", |
239 | page_ext->order, page_ext->gfp_mask, | |
240 | &page_ext->gfp_mask); | |
48c96a36 JK |
241 | |
242 | if (ret >= count) | |
243 | goto err; | |
244 | ||
245 | /* Print information relevant to grouping pages by mobility */ | |
0b423ca2 | 246 | pageblock_mt = get_pageblock_migratetype(page); |
48c96a36 JK |
247 | page_mt = gfpflags_to_migratetype(page_ext->gfp_mask); |
248 | ret += snprintf(kbuf + ret, count - ret, | |
60f30350 | 249 | "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n", |
48c96a36 | 250 | pfn, |
60f30350 | 251 | migratetype_names[page_mt], |
48c96a36 | 252 | pfn >> pageblock_order, |
60f30350 VB |
253 | migratetype_names[pageblock_mt], |
254 | page->flags, &page->flags); | |
48c96a36 JK |
255 | |
256 | if (ret >= count) | |
257 | goto err; | |
258 | ||
f2ca0b55 | 259 | depot_fetch_stack(handle, &trace); |
94f759d6 | 260 | ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0); |
48c96a36 JK |
261 | if (ret >= count) |
262 | goto err; | |
263 | ||
7cd12b4a VB |
264 | if (page_ext->last_migrate_reason != -1) { |
265 | ret += snprintf(kbuf + ret, count - ret, | |
266 | "Page has been migrated, last migrate reason: %s\n", | |
267 | migrate_reason_names[page_ext->last_migrate_reason]); | |
268 | if (ret >= count) | |
269 | goto err; | |
270 | } | |
271 | ||
48c96a36 JK |
272 | ret += snprintf(kbuf + ret, count - ret, "\n"); |
273 | if (ret >= count) | |
274 | goto err; | |
275 | ||
276 | if (copy_to_user(buf, kbuf, ret)) | |
277 | ret = -EFAULT; | |
278 | ||
279 | kfree(kbuf); | |
280 | return ret; | |
281 | ||
282 | err: | |
283 | kfree(kbuf); | |
284 | return -ENOMEM; | |
285 | } | |
286 | ||
4e462112 VB |
287 | void __dump_page_owner(struct page *page) |
288 | { | |
289 | struct page_ext *page_ext = lookup_page_ext(page); | |
f2ca0b55 | 290 | unsigned long entries[PAGE_OWNER_STACK_DEPTH]; |
4e462112 | 291 | struct stack_trace trace = { |
f2ca0b55 JK |
292 | .nr_entries = 0, |
293 | .entries = entries, | |
294 | .max_entries = PAGE_OWNER_STACK_DEPTH, | |
295 | .skip = 0 | |
4e462112 | 296 | }; |
f2ca0b55 | 297 | depot_stack_handle_t handle; |
8285027f SM |
298 | gfp_t gfp_mask; |
299 | int mt; | |
4e462112 | 300 | |
f86e4271 YS |
301 | if (unlikely(!page_ext)) { |
302 | pr_alert("There is not page extension available.\n"); | |
303 | return; | |
304 | } | |
8285027f SM |
305 | gfp_mask = page_ext->gfp_mask; |
306 | mt = gfpflags_to_migratetype(gfp_mask); | |
f86e4271 | 307 | |
4e462112 VB |
308 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) { |
309 | pr_alert("page_owner info is not active (free page?)\n"); | |
310 | return; | |
311 | } | |
312 | ||
f2ca0b55 JK |
313 | handle = READ_ONCE(page_ext->handle); |
314 | if (!handle) { | |
315 | pr_alert("page_owner info is not active (free page?)\n"); | |
316 | return; | |
317 | } | |
318 | ||
319 | depot_fetch_stack(handle, &trace); | |
756a025f JP |
320 | pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n", |
321 | page_ext->order, migratetype_names[mt], gfp_mask, &gfp_mask); | |
4e462112 VB |
322 | print_stack_trace(&trace, 0); |
323 | ||
324 | if (page_ext->last_migrate_reason != -1) | |
325 | pr_alert("page has been migrated, last migrate reason: %s\n", | |
326 | migrate_reason_names[page_ext->last_migrate_reason]); | |
327 | } | |
328 | ||
48c96a36 JK |
329 | static ssize_t |
330 | read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
331 | { | |
332 | unsigned long pfn; | |
333 | struct page *page; | |
334 | struct page_ext *page_ext; | |
f2ca0b55 | 335 | depot_stack_handle_t handle; |
48c96a36 | 336 | |
7dd80b8a | 337 | if (!static_branch_unlikely(&page_owner_inited)) |
48c96a36 JK |
338 | return -EINVAL; |
339 | ||
340 | page = NULL; | |
341 | pfn = min_low_pfn + *ppos; | |
342 | ||
343 | /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ | |
344 | while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) | |
345 | pfn++; | |
346 | ||
347 | drain_all_pages(NULL); | |
348 | ||
349 | /* Find an allocated page */ | |
350 | for (; pfn < max_pfn; pfn++) { | |
351 | /* | |
352 | * If the new page is in a new MAX_ORDER_NR_PAGES area, | |
353 | * validate the area as existing, skip it if not | |
354 | */ | |
355 | if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) { | |
356 | pfn += MAX_ORDER_NR_PAGES - 1; | |
357 | continue; | |
358 | } | |
359 | ||
360 | /* Check for holes within a MAX_ORDER area */ | |
361 | if (!pfn_valid_within(pfn)) | |
362 | continue; | |
363 | ||
364 | page = pfn_to_page(pfn); | |
365 | if (PageBuddy(page)) { | |
366 | unsigned long freepage_order = page_order_unsafe(page); | |
367 | ||
368 | if (freepage_order < MAX_ORDER) | |
369 | pfn += (1UL << freepage_order) - 1; | |
370 | continue; | |
371 | } | |
372 | ||
373 | page_ext = lookup_page_ext(page); | |
f86e4271 YS |
374 | if (unlikely(!page_ext)) |
375 | continue; | |
48c96a36 JK |
376 | |
377 | /* | |
61cf5feb JK |
378 | * Some pages could be missed by concurrent allocation or free, |
379 | * because we don't hold the zone lock. | |
48c96a36 JK |
380 | */ |
381 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) | |
382 | continue; | |
383 | ||
f2ca0b55 JK |
384 | /* |
385 | * Access to page_ext->handle isn't synchronous so we should | |
386 | * be careful to access it. | |
387 | */ | |
388 | handle = READ_ONCE(page_ext->handle); | |
389 | if (!handle) | |
390 | continue; | |
391 | ||
48c96a36 JK |
392 | /* Record the next PFN to read in the file offset */ |
393 | *ppos = (pfn - min_low_pfn) + 1; | |
394 | ||
f2ca0b55 JK |
395 | return print_page_owner(buf, count, pfn, page, |
396 | page_ext, handle); | |
48c96a36 JK |
397 | } |
398 | ||
399 | return 0; | |
400 | } | |
401 | ||
61cf5feb JK |
402 | static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) |
403 | { | |
404 | struct page *page; | |
405 | struct page_ext *page_ext; | |
406 | unsigned long pfn = zone->zone_start_pfn, block_end_pfn; | |
407 | unsigned long end_pfn = pfn + zone->spanned_pages; | |
408 | unsigned long count = 0; | |
409 | ||
410 | /* Scan block by block. First and last block may be incomplete */ | |
411 | pfn = zone->zone_start_pfn; | |
412 | ||
413 | /* | |
414 | * Walk the zone in pageblock_nr_pages steps. If a page block spans | |
415 | * a zone boundary, it will be double counted between zones. This does | |
416 | * not matter as the mixed block count will still be correct | |
417 | */ | |
418 | for (; pfn < end_pfn; ) { | |
419 | if (!pfn_valid(pfn)) { | |
420 | pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); | |
421 | continue; | |
422 | } | |
423 | ||
424 | block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); | |
425 | block_end_pfn = min(block_end_pfn, end_pfn); | |
426 | ||
427 | page = pfn_to_page(pfn); | |
428 | ||
429 | for (; pfn < block_end_pfn; pfn++) { | |
430 | if (!pfn_valid_within(pfn)) | |
431 | continue; | |
432 | ||
433 | page = pfn_to_page(pfn); | |
434 | ||
9d43f5ae JK |
435 | if (page_zone(page) != zone) |
436 | continue; | |
437 | ||
61cf5feb JK |
438 | /* |
439 | * We are safe to check buddy flag and order, because | |
440 | * this is init stage and only single thread runs. | |
441 | */ | |
442 | if (PageBuddy(page)) { | |
443 | pfn += (1UL << page_order(page)) - 1; | |
444 | continue; | |
445 | } | |
446 | ||
447 | if (PageReserved(page)) | |
448 | continue; | |
449 | ||
450 | page_ext = lookup_page_ext(page); | |
f86e4271 YS |
451 | if (unlikely(!page_ext)) |
452 | continue; | |
61cf5feb JK |
453 | |
454 | /* Maybe overraping zone */ | |
455 | if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) | |
456 | continue; | |
457 | ||
458 | /* Found early allocated page */ | |
459 | set_page_owner(page, 0, 0); | |
460 | count++; | |
461 | } | |
462 | } | |
463 | ||
464 | pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n", | |
465 | pgdat->node_id, zone->name, count); | |
466 | } | |
467 | ||
468 | static void init_zones_in_node(pg_data_t *pgdat) | |
469 | { | |
470 | struct zone *zone; | |
471 | struct zone *node_zones = pgdat->node_zones; | |
472 | unsigned long flags; | |
473 | ||
474 | for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { | |
475 | if (!populated_zone(zone)) | |
476 | continue; | |
477 | ||
478 | spin_lock_irqsave(&zone->lock, flags); | |
479 | init_pages_in_zone(pgdat, zone); | |
480 | spin_unlock_irqrestore(&zone->lock, flags); | |
481 | } | |
482 | } | |
483 | ||
484 | static void init_early_allocated_pages(void) | |
485 | { | |
486 | pg_data_t *pgdat; | |
487 | ||
488 | drain_all_pages(NULL); | |
489 | for_each_online_pgdat(pgdat) | |
490 | init_zones_in_node(pgdat); | |
491 | } | |
492 | ||
48c96a36 JK |
493 | static const struct file_operations proc_page_owner_operations = { |
494 | .read = read_page_owner, | |
495 | }; | |
496 | ||
497 | static int __init pageowner_init(void) | |
498 | { | |
499 | struct dentry *dentry; | |
500 | ||
7dd80b8a | 501 | if (!static_branch_unlikely(&page_owner_inited)) { |
48c96a36 JK |
502 | pr_info("page_owner is disabled\n"); |
503 | return 0; | |
504 | } | |
505 | ||
506 | dentry = debugfs_create_file("page_owner", S_IRUSR, NULL, | |
507 | NULL, &proc_page_owner_operations); | |
508 | if (IS_ERR(dentry)) | |
509 | return PTR_ERR(dentry); | |
510 | ||
511 | return 0; | |
512 | } | |
44c5af96 | 513 | late_initcall(pageowner_init) |