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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> | |
8 | #include <linux/jump_label.h> | |
9 | #include <linux/migrate.h> | |
10 | #include <linux/stackdepot.h> | |
11 | #include <linux/seq_file.h> | |
12 | ||
13 | #include "internal.h" | |
14 | ||
15 | /* | |
16 | * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack) | |
17 | * to use off stack temporal storage | |
18 | */ | |
19 | #define PAGE_OWNER_STACK_DEPTH (16) | |
20 | ||
21 | struct page_owner { | |
22 | unsigned int order; | |
23 | gfp_t gfp_mask; | |
24 | int last_migrate_reason; | |
25 | depot_stack_handle_t handle; | |
26 | }; | |
27 | ||
28 | static bool page_owner_disabled = true; | |
29 | DEFINE_STATIC_KEY_FALSE(page_owner_inited); | |
30 | ||
31 | static depot_stack_handle_t dummy_handle; | |
32 | static depot_stack_handle_t failure_handle; | |
33 | ||
34 | static void init_early_allocated_pages(void); | |
35 | ||
36 | static int early_page_owner_param(char *buf) | |
37 | { | |
38 | if (!buf) | |
39 | return -EINVAL; | |
40 | ||
41 | if (strcmp(buf, "on") == 0) | |
42 | page_owner_disabled = false; | |
43 | ||
44 | return 0; | |
45 | } | |
46 | early_param("page_owner", early_page_owner_param); | |
47 | ||
48 | static bool need_page_owner(void) | |
49 | { | |
50 | if (page_owner_disabled) | |
51 | return false; | |
52 | ||
53 | return true; | |
54 | } | |
55 | ||
56 | static noinline void register_dummy_stack(void) | |
57 | { | |
58 | unsigned long entries[4]; | |
59 | struct stack_trace dummy; | |
60 | ||
61 | dummy.nr_entries = 0; | |
62 | dummy.max_entries = ARRAY_SIZE(entries); | |
63 | dummy.entries = &entries[0]; | |
64 | dummy.skip = 0; | |
65 | ||
66 | save_stack_trace(&dummy); | |
67 | dummy_handle = depot_save_stack(&dummy, GFP_KERNEL); | |
68 | } | |
69 | ||
70 | static noinline void register_failure_stack(void) | |
71 | { | |
72 | unsigned long entries[4]; | |
73 | struct stack_trace failure; | |
74 | ||
75 | failure.nr_entries = 0; | |
76 | failure.max_entries = ARRAY_SIZE(entries); | |
77 | failure.entries = &entries[0]; | |
78 | failure.skip = 0; | |
79 | ||
80 | save_stack_trace(&failure); | |
81 | failure_handle = depot_save_stack(&failure, GFP_KERNEL); | |
82 | } | |
83 | ||
84 | static void init_page_owner(void) | |
85 | { | |
86 | if (page_owner_disabled) | |
87 | return; | |
88 | ||
89 | register_dummy_stack(); | |
90 | register_failure_stack(); | |
91 | static_branch_enable(&page_owner_inited); | |
92 | init_early_allocated_pages(); | |
93 | } | |
94 | ||
95 | struct page_ext_operations page_owner_ops = { | |
96 | .size = sizeof(struct page_owner), | |
97 | .need = need_page_owner, | |
98 | .init = init_page_owner, | |
99 | }; | |
100 | ||
101 | static inline struct page_owner *get_page_owner(struct page_ext *page_ext) | |
102 | { | |
103 | return (void *)page_ext + page_owner_ops.offset; | |
104 | } | |
105 | ||
106 | void __reset_page_owner(struct page *page, unsigned int order) | |
107 | { | |
108 | int i; | |
109 | struct page_ext *page_ext; | |
110 | ||
111 | for (i = 0; i < (1 << order); i++) { | |
112 | page_ext = lookup_page_ext(page + i); | |
113 | if (unlikely(!page_ext)) | |
114 | continue; | |
115 | __clear_bit(PAGE_EXT_OWNER, &page_ext->flags); | |
116 | } | |
117 | } | |
118 | ||
119 | static inline bool check_recursive_alloc(struct stack_trace *trace, | |
120 | unsigned long ip) | |
121 | { | |
122 | int i, count; | |
123 | ||
124 | if (!trace->nr_entries) | |
125 | return false; | |
126 | ||
127 | for (i = 0, count = 0; i < trace->nr_entries; i++) { | |
128 | if (trace->entries[i] == ip && ++count == 2) | |
129 | return true; | |
130 | } | |
131 | ||
132 | return false; | |
133 | } | |
134 | ||
135 | static noinline depot_stack_handle_t save_stack(gfp_t flags) | |
136 | { | |
137 | unsigned long entries[PAGE_OWNER_STACK_DEPTH]; | |
138 | struct stack_trace trace = { | |
139 | .nr_entries = 0, | |
140 | .entries = entries, | |
141 | .max_entries = PAGE_OWNER_STACK_DEPTH, | |
142 | .skip = 0 | |
143 | }; | |
144 | depot_stack_handle_t handle; | |
145 | ||
146 | save_stack_trace(&trace); | |
147 | if (trace.nr_entries != 0 && | |
148 | trace.entries[trace.nr_entries-1] == ULONG_MAX) | |
149 | trace.nr_entries--; | |
150 | ||
151 | /* | |
152 | * We need to check recursion here because our request to stackdepot | |
153 | * could trigger memory allocation to save new entry. New memory | |
154 | * allocation would reach here and call depot_save_stack() again | |
155 | * if we don't catch it. There is still not enough memory in stackdepot | |
156 | * so it would try to allocate memory again and loop forever. | |
157 | */ | |
158 | if (check_recursive_alloc(&trace, _RET_IP_)) | |
159 | return dummy_handle; | |
160 | ||
161 | handle = depot_save_stack(&trace, flags); | |
162 | if (!handle) | |
163 | handle = failure_handle; | |
164 | ||
165 | return handle; | |
166 | } | |
167 | ||
168 | noinline void __set_page_owner(struct page *page, unsigned int order, | |
169 | gfp_t gfp_mask) | |
170 | { | |
171 | struct page_ext *page_ext = lookup_page_ext(page); | |
172 | struct page_owner *page_owner; | |
173 | ||
174 | if (unlikely(!page_ext)) | |
175 | return; | |
176 | ||
177 | page_owner = get_page_owner(page_ext); | |
178 | page_owner->handle = save_stack(gfp_mask); | |
179 | page_owner->order = order; | |
180 | page_owner->gfp_mask = gfp_mask; | |
181 | page_owner->last_migrate_reason = -1; | |
182 | ||
183 | __set_bit(PAGE_EXT_OWNER, &page_ext->flags); | |
184 | } | |
185 | ||
186 | void __set_page_owner_migrate_reason(struct page *page, int reason) | |
187 | { | |
188 | struct page_ext *page_ext = lookup_page_ext(page); | |
189 | struct page_owner *page_owner; | |
190 | ||
191 | if (unlikely(!page_ext)) | |
192 | return; | |
193 | ||
194 | page_owner = get_page_owner(page_ext); | |
195 | page_owner->last_migrate_reason = reason; | |
196 | } | |
197 | ||
198 | void __split_page_owner(struct page *page, unsigned int order) | |
199 | { | |
200 | int i; | |
201 | struct page_ext *page_ext = lookup_page_ext(page); | |
202 | struct page_owner *page_owner; | |
203 | ||
204 | if (unlikely(!page_ext)) | |
205 | return; | |
206 | ||
207 | page_owner = get_page_owner(page_ext); | |
208 | page_owner->order = 0; | |
209 | for (i = 1; i < (1 << order); i++) | |
210 | __copy_page_owner(page, page + i); | |
211 | } | |
212 | ||
213 | void __copy_page_owner(struct page *oldpage, struct page *newpage) | |
214 | { | |
215 | struct page_ext *old_ext = lookup_page_ext(oldpage); | |
216 | struct page_ext *new_ext = lookup_page_ext(newpage); | |
217 | struct page_owner *old_page_owner, *new_page_owner; | |
218 | ||
219 | if (unlikely(!old_ext || !new_ext)) | |
220 | return; | |
221 | ||
222 | old_page_owner = get_page_owner(old_ext); | |
223 | new_page_owner = get_page_owner(new_ext); | |
224 | new_page_owner->order = old_page_owner->order; | |
225 | new_page_owner->gfp_mask = old_page_owner->gfp_mask; | |
226 | new_page_owner->last_migrate_reason = | |
227 | old_page_owner->last_migrate_reason; | |
228 | new_page_owner->handle = old_page_owner->handle; | |
229 | ||
230 | /* | |
231 | * We don't clear the bit on the oldpage as it's going to be freed | |
232 | * after migration. Until then, the info can be useful in case of | |
233 | * a bug, and the overal stats will be off a bit only temporarily. | |
234 | * Also, migrate_misplaced_transhuge_page() can still fail the | |
235 | * migration and then we want the oldpage to retain the info. But | |
236 | * in that case we also don't need to explicitly clear the info from | |
237 | * the new page, which will be freed. | |
238 | */ | |
239 | __set_bit(PAGE_EXT_OWNER, &new_ext->flags); | |
240 | } | |
241 | ||
242 | void pagetypeinfo_showmixedcount_print(struct seq_file *m, | |
243 | pg_data_t *pgdat, struct zone *zone) | |
244 | { | |
245 | struct page *page; | |
246 | struct page_ext *page_ext; | |
247 | struct page_owner *page_owner; | |
248 | unsigned long pfn = zone->zone_start_pfn, block_end_pfn; | |
249 | unsigned long end_pfn = pfn + zone->spanned_pages; | |
250 | unsigned long count[MIGRATE_TYPES] = { 0, }; | |
251 | int pageblock_mt, page_mt; | |
252 | int i; | |
253 | ||
254 | /* Scan block by block. First and last block may be incomplete */ | |
255 | pfn = zone->zone_start_pfn; | |
256 | ||
257 | /* | |
258 | * Walk the zone in pageblock_nr_pages steps. If a page block spans | |
259 | * a zone boundary, it will be double counted between zones. This does | |
260 | * not matter as the mixed block count will still be correct | |
261 | */ | |
262 | for (; pfn < end_pfn; ) { | |
263 | if (!pfn_valid(pfn)) { | |
264 | pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); | |
265 | continue; | |
266 | } | |
267 | ||
268 | block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); | |
269 | block_end_pfn = min(block_end_pfn, end_pfn); | |
270 | ||
271 | page = pfn_to_page(pfn); | |
272 | pageblock_mt = get_pageblock_migratetype(page); | |
273 | ||
274 | for (; pfn < block_end_pfn; pfn++) { | |
275 | if (!pfn_valid_within(pfn)) | |
276 | continue; | |
277 | ||
278 | page = pfn_to_page(pfn); | |
279 | ||
280 | if (page_zone(page) != zone) | |
281 | continue; | |
282 | ||
283 | if (PageBuddy(page)) { | |
284 | unsigned long freepage_order; | |
285 | ||
286 | freepage_order = page_order_unsafe(page); | |
287 | if (freepage_order < MAX_ORDER) | |
288 | pfn += (1UL << freepage_order) - 1; | |
289 | continue; | |
290 | } | |
291 | ||
292 | if (PageReserved(page)) | |
293 | continue; | |
294 | ||
295 | page_ext = lookup_page_ext(page); | |
296 | if (unlikely(!page_ext)) | |
297 | continue; | |
298 | ||
299 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) | |
300 | continue; | |
301 | ||
302 | page_owner = get_page_owner(page_ext); | |
303 | page_mt = gfpflags_to_migratetype( | |
304 | page_owner->gfp_mask); | |
305 | if (pageblock_mt != page_mt) { | |
306 | if (is_migrate_cma(pageblock_mt)) | |
307 | count[MIGRATE_MOVABLE]++; | |
308 | else | |
309 | count[pageblock_mt]++; | |
310 | ||
311 | pfn = block_end_pfn; | |
312 | break; | |
313 | } | |
314 | pfn += (1UL << page_owner->order) - 1; | |
315 | } | |
316 | } | |
317 | ||
318 | /* Print counts */ | |
319 | seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name); | |
320 | for (i = 0; i < MIGRATE_TYPES; i++) | |
321 | seq_printf(m, "%12lu ", count[i]); | |
322 | seq_putc(m, '\n'); | |
323 | } | |
324 | ||
325 | static ssize_t | |
326 | print_page_owner(char __user *buf, size_t count, unsigned long pfn, | |
327 | struct page *page, struct page_owner *page_owner, | |
328 | depot_stack_handle_t handle) | |
329 | { | |
330 | int ret; | |
331 | int pageblock_mt, page_mt; | |
332 | char *kbuf; | |
333 | unsigned long entries[PAGE_OWNER_STACK_DEPTH]; | |
334 | struct stack_trace trace = { | |
335 | .nr_entries = 0, | |
336 | .entries = entries, | |
337 | .max_entries = PAGE_OWNER_STACK_DEPTH, | |
338 | .skip = 0 | |
339 | }; | |
340 | ||
341 | kbuf = kmalloc(count, GFP_KERNEL); | |
342 | if (!kbuf) | |
343 | return -ENOMEM; | |
344 | ||
345 | ret = snprintf(kbuf, count, | |
346 | "Page allocated via order %u, mask %#x(%pGg)\n", | |
347 | page_owner->order, page_owner->gfp_mask, | |
348 | &page_owner->gfp_mask); | |
349 | ||
350 | if (ret >= count) | |
351 | goto err; | |
352 | ||
353 | /* Print information relevant to grouping pages by mobility */ | |
354 | pageblock_mt = get_pageblock_migratetype(page); | |
355 | page_mt = gfpflags_to_migratetype(page_owner->gfp_mask); | |
356 | ret += snprintf(kbuf + ret, count - ret, | |
357 | "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n", | |
358 | pfn, | |
359 | migratetype_names[page_mt], | |
360 | pfn >> pageblock_order, | |
361 | migratetype_names[pageblock_mt], | |
362 | page->flags, &page->flags); | |
363 | ||
364 | if (ret >= count) | |
365 | goto err; | |
366 | ||
367 | depot_fetch_stack(handle, &trace); | |
368 | ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0); | |
369 | if (ret >= count) | |
370 | goto err; | |
371 | ||
372 | if (page_owner->last_migrate_reason != -1) { | |
373 | ret += snprintf(kbuf + ret, count - ret, | |
374 | "Page has been migrated, last migrate reason: %s\n", | |
375 | migrate_reason_names[page_owner->last_migrate_reason]); | |
376 | if (ret >= count) | |
377 | goto err; | |
378 | } | |
379 | ||
380 | ret += snprintf(kbuf + ret, count - ret, "\n"); | |
381 | if (ret >= count) | |
382 | goto err; | |
383 | ||
384 | if (copy_to_user(buf, kbuf, ret)) | |
385 | ret = -EFAULT; | |
386 | ||
387 | kfree(kbuf); | |
388 | return ret; | |
389 | ||
390 | err: | |
391 | kfree(kbuf); | |
392 | return -ENOMEM; | |
393 | } | |
394 | ||
395 | void __dump_page_owner(struct page *page) | |
396 | { | |
397 | struct page_ext *page_ext = lookup_page_ext(page); | |
398 | struct page_owner *page_owner; | |
399 | unsigned long entries[PAGE_OWNER_STACK_DEPTH]; | |
400 | struct stack_trace trace = { | |
401 | .nr_entries = 0, | |
402 | .entries = entries, | |
403 | .max_entries = PAGE_OWNER_STACK_DEPTH, | |
404 | .skip = 0 | |
405 | }; | |
406 | depot_stack_handle_t handle; | |
407 | gfp_t gfp_mask; | |
408 | int mt; | |
409 | ||
410 | if (unlikely(!page_ext)) { | |
411 | pr_alert("There is not page extension available.\n"); | |
412 | return; | |
413 | } | |
414 | ||
415 | page_owner = get_page_owner(page_ext); | |
416 | gfp_mask = page_owner->gfp_mask; | |
417 | mt = gfpflags_to_migratetype(gfp_mask); | |
418 | ||
419 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) { | |
420 | pr_alert("page_owner info is not active (free page?)\n"); | |
421 | return; | |
422 | } | |
423 | ||
424 | handle = READ_ONCE(page_owner->handle); | |
425 | if (!handle) { | |
426 | pr_alert("page_owner info is not active (free page?)\n"); | |
427 | return; | |
428 | } | |
429 | ||
430 | depot_fetch_stack(handle, &trace); | |
431 | pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n", | |
432 | page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask); | |
433 | print_stack_trace(&trace, 0); | |
434 | ||
435 | if (page_owner->last_migrate_reason != -1) | |
436 | pr_alert("page has been migrated, last migrate reason: %s\n", | |
437 | migrate_reason_names[page_owner->last_migrate_reason]); | |
438 | } | |
439 | ||
440 | static ssize_t | |
441 | read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
442 | { | |
443 | unsigned long pfn; | |
444 | struct page *page; | |
445 | struct page_ext *page_ext; | |
446 | struct page_owner *page_owner; | |
447 | depot_stack_handle_t handle; | |
448 | ||
449 | if (!static_branch_unlikely(&page_owner_inited)) | |
450 | return -EINVAL; | |
451 | ||
452 | page = NULL; | |
453 | pfn = min_low_pfn + *ppos; | |
454 | ||
455 | /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ | |
456 | while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) | |
457 | pfn++; | |
458 | ||
459 | drain_all_pages(NULL); | |
460 | ||
461 | /* Find an allocated page */ | |
462 | for (; pfn < max_pfn; pfn++) { | |
463 | /* | |
464 | * If the new page is in a new MAX_ORDER_NR_PAGES area, | |
465 | * validate the area as existing, skip it if not | |
466 | */ | |
467 | if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) { | |
468 | pfn += MAX_ORDER_NR_PAGES - 1; | |
469 | continue; | |
470 | } | |
471 | ||
472 | /* Check for holes within a MAX_ORDER area */ | |
473 | if (!pfn_valid_within(pfn)) | |
474 | continue; | |
475 | ||
476 | page = pfn_to_page(pfn); | |
477 | if (PageBuddy(page)) { | |
478 | unsigned long freepage_order = page_order_unsafe(page); | |
479 | ||
480 | if (freepage_order < MAX_ORDER) | |
481 | pfn += (1UL << freepage_order) - 1; | |
482 | continue; | |
483 | } | |
484 | ||
485 | page_ext = lookup_page_ext(page); | |
486 | if (unlikely(!page_ext)) | |
487 | continue; | |
488 | ||
489 | /* | |
490 | * Some pages could be missed by concurrent allocation or free, | |
491 | * because we don't hold the zone lock. | |
492 | */ | |
493 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) | |
494 | continue; | |
495 | ||
496 | page_owner = get_page_owner(page_ext); | |
497 | ||
498 | /* | |
499 | * Access to page_ext->handle isn't synchronous so we should | |
500 | * be careful to access it. | |
501 | */ | |
502 | handle = READ_ONCE(page_owner->handle); | |
503 | if (!handle) | |
504 | continue; | |
505 | ||
506 | /* Record the next PFN to read in the file offset */ | |
507 | *ppos = (pfn - min_low_pfn) + 1; | |
508 | ||
509 | return print_page_owner(buf, count, pfn, page, | |
510 | page_owner, handle); | |
511 | } | |
512 | ||
513 | return 0; | |
514 | } | |
515 | ||
516 | static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) | |
517 | { | |
518 | struct page *page; | |
519 | struct page_ext *page_ext; | |
520 | unsigned long pfn = zone->zone_start_pfn, block_end_pfn; | |
521 | unsigned long end_pfn = pfn + zone->spanned_pages; | |
522 | unsigned long count = 0; | |
523 | ||
524 | /* Scan block by block. First and last block may be incomplete */ | |
525 | pfn = zone->zone_start_pfn; | |
526 | ||
527 | /* | |
528 | * Walk the zone in pageblock_nr_pages steps. If a page block spans | |
529 | * a zone boundary, it will be double counted between zones. This does | |
530 | * not matter as the mixed block count will still be correct | |
531 | */ | |
532 | for (; pfn < end_pfn; ) { | |
533 | if (!pfn_valid(pfn)) { | |
534 | pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES); | |
535 | continue; | |
536 | } | |
537 | ||
538 | block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages); | |
539 | block_end_pfn = min(block_end_pfn, end_pfn); | |
540 | ||
541 | page = pfn_to_page(pfn); | |
542 | ||
543 | for (; pfn < block_end_pfn; pfn++) { | |
544 | if (!pfn_valid_within(pfn)) | |
545 | continue; | |
546 | ||
547 | page = pfn_to_page(pfn); | |
548 | ||
549 | if (page_zone(page) != zone) | |
550 | continue; | |
551 | ||
552 | /* | |
553 | * We are safe to check buddy flag and order, because | |
554 | * this is init stage and only single thread runs. | |
555 | */ | |
556 | if (PageBuddy(page)) { | |
557 | pfn += (1UL << page_order(page)) - 1; | |
558 | continue; | |
559 | } | |
560 | ||
561 | if (PageReserved(page)) | |
562 | continue; | |
563 | ||
564 | page_ext = lookup_page_ext(page); | |
565 | if (unlikely(!page_ext)) | |
566 | continue; | |
567 | ||
568 | /* Maybe overraping zone */ | |
569 | if (test_bit(PAGE_EXT_OWNER, &page_ext->flags)) | |
570 | continue; | |
571 | ||
572 | /* Found early allocated page */ | |
573 | set_page_owner(page, 0, 0); | |
574 | count++; | |
575 | } | |
576 | } | |
577 | ||
578 | pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n", | |
579 | pgdat->node_id, zone->name, count); | |
580 | } | |
581 | ||
582 | static void init_zones_in_node(pg_data_t *pgdat) | |
583 | { | |
584 | struct zone *zone; | |
585 | struct zone *node_zones = pgdat->node_zones; | |
586 | unsigned long flags; | |
587 | ||
588 | for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { | |
589 | if (!populated_zone(zone)) | |
590 | continue; | |
591 | ||
592 | spin_lock_irqsave(&zone->lock, flags); | |
593 | init_pages_in_zone(pgdat, zone); | |
594 | spin_unlock_irqrestore(&zone->lock, flags); | |
595 | } | |
596 | } | |
597 | ||
598 | static void init_early_allocated_pages(void) | |
599 | { | |
600 | pg_data_t *pgdat; | |
601 | ||
602 | drain_all_pages(NULL); | |
603 | for_each_online_pgdat(pgdat) | |
604 | init_zones_in_node(pgdat); | |
605 | } | |
606 | ||
607 | static const struct file_operations proc_page_owner_operations = { | |
608 | .read = read_page_owner, | |
609 | }; | |
610 | ||
611 | static int __init pageowner_init(void) | |
612 | { | |
613 | struct dentry *dentry; | |
614 | ||
615 | if (!static_branch_unlikely(&page_owner_inited)) { | |
616 | pr_info("page_owner is disabled\n"); | |
617 | return 0; | |
618 | } | |
619 | ||
620 | dentry = debugfs_create_file("page_owner", S_IRUSR, NULL, | |
621 | NULL, &proc_page_owner_operations); | |
622 | if (IS_ERR(dentry)) | |
623 | return PTR_ERR(dentry); | |
624 | ||
625 | return 0; | |
626 | } | |
627 | late_initcall(pageowner_init) |