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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/bootmem.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
22struct page_owner {
23 unsigned short order;
24 short last_migrate_reason;
25 gfp_t gfp_mask;
26 depot_stack_handle_t handle;
27};
28
29static bool page_owner_disabled = true;
30DEFINE_STATIC_KEY_FALSE(page_owner_inited);
31
32static depot_stack_handle_t dummy_handle;
33static depot_stack_handle_t failure_handle;
34static depot_stack_handle_t early_handle;
35
36static void init_early_allocated_pages(void);
37
38static 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}
48early_param("page_owner", early_page_owner_param);
49
50static bool need_page_owner(void)
51{
52 if (page_owner_disabled)
53 return false;
54
55 return true;
56}
57
58static __always_inline depot_stack_handle_t create_dummy_stack(void)
59{
60 unsigned long entries[4];
61 struct stack_trace dummy;
62
63 dummy.nr_entries = 0;
64 dummy.max_entries = ARRAY_SIZE(entries);
65 dummy.entries = &entries[0];
66 dummy.skip = 0;
67
68 save_stack_trace(&dummy);
69 return depot_save_stack(&dummy, GFP_KERNEL);
70}
71
72static noinline void register_dummy_stack(void)
73{
74 dummy_handle = create_dummy_stack();
75}
76
77static noinline void register_failure_stack(void)
78{
79 failure_handle = create_dummy_stack();
80}
81
82static noinline void register_early_stack(void)
83{
84 early_handle = create_dummy_stack();
85}
86
87static void init_page_owner(void)
88{
89 if (page_owner_disabled)
90 return;
91
92 register_dummy_stack();
93 register_failure_stack();
94 register_early_stack();
95 static_branch_enable(&page_owner_inited);
96 init_early_allocated_pages();
97}
98
99struct page_ext_operations page_owner_ops = {
100 .size = sizeof(struct page_owner),
101 .need = need_page_owner,
102 .init = init_page_owner,
103};
104
105static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
106{
107 return (void *)page_ext + page_owner_ops.offset;
108}
109
110void __reset_page_owner(struct page *page, unsigned int order)
111{
112 int i;
113 struct page_ext *page_ext;
114
115 for (i = 0; i < (1 << order); i++) {
116 page_ext = lookup_page_ext(page + i);
117 if (unlikely(!page_ext))
118 continue;
119 __clear_bit(PAGE_EXT_OWNER, &page_ext->flags);
120 }
121}
122
123static inline bool check_recursive_alloc(struct stack_trace *trace,
124 unsigned long ip)
125{
126 int i;
127
128 if (!trace->nr_entries)
129 return false;
130
131 for (i = 0; i < trace->nr_entries; i++) {
132 if (trace->entries[i] == ip)
133 return true;
134 }
135
136 return false;
137}
138
139static noinline depot_stack_handle_t save_stack(gfp_t flags)
140{
141 unsigned long entries[PAGE_OWNER_STACK_DEPTH];
142 struct stack_trace trace = {
143 .nr_entries = 0,
144 .entries = entries,
145 .max_entries = PAGE_OWNER_STACK_DEPTH,
146 .skip = 2
147 };
148 depot_stack_handle_t handle;
149
150 save_stack_trace(&trace);
151 if (trace.nr_entries != 0 &&
152 trace.entries[trace.nr_entries-1] == ULONG_MAX)
153 trace.nr_entries--;
154
155 /*
156 * We need to check recursion here because our request to stackdepot
157 * could trigger memory allocation to save new entry. New memory
158 * allocation would reach here and call depot_save_stack() again
159 * if we don't catch it. There is still not enough memory in stackdepot
160 * so it would try to allocate memory again and loop forever.
161 */
162 if (check_recursive_alloc(&trace, _RET_IP_))
163 return dummy_handle;
164
165 handle = depot_save_stack(&trace, flags);
166 if (!handle)
167 handle = failure_handle;
168
169 return handle;
170}
171
172static inline void __set_page_owner_handle(struct page_ext *page_ext,
173 depot_stack_handle_t handle, unsigned int order, gfp_t gfp_mask)
174{
175 struct page_owner *page_owner;
176
177 page_owner = get_page_owner(page_ext);
178 page_owner->handle = handle;
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
186noinline void __set_page_owner(struct page *page, unsigned int order,
187 gfp_t gfp_mask)
188{
189 struct page_ext *page_ext = lookup_page_ext(page);
190 depot_stack_handle_t handle;
191
192 if (unlikely(!page_ext))
193 return;
194
195 handle = save_stack(gfp_mask);
196 __set_page_owner_handle(page_ext, handle, order, gfp_mask);
197}
198
199void __set_page_owner_migrate_reason(struct page *page, int reason)
200{
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->last_migrate_reason = reason;
209}
210
211void __split_page_owner(struct page *page, unsigned int order)
212{
213 int i;
214 struct page_ext *page_ext = lookup_page_ext(page);
215 struct page_owner *page_owner;
216
217 if (unlikely(!page_ext))
218 return;
219
220 page_owner = get_page_owner(page_ext);
221 page_owner->order = 0;
222 for (i = 1; i < (1 << order); i++)
223 __copy_page_owner(page, page + i);
224}
225
226void __copy_page_owner(struct page *oldpage, struct page *newpage)
227{
228 struct page_ext *old_ext = lookup_page_ext(oldpage);
229 struct page_ext *new_ext = lookup_page_ext(newpage);
230 struct page_owner *old_page_owner, *new_page_owner;
231
232 if (unlikely(!old_ext || !new_ext))
233 return;
234
235 old_page_owner = get_page_owner(old_ext);
236 new_page_owner = get_page_owner(new_ext);
237 new_page_owner->order = old_page_owner->order;
238 new_page_owner->gfp_mask = old_page_owner->gfp_mask;
239 new_page_owner->last_migrate_reason =
240 old_page_owner->last_migrate_reason;
241 new_page_owner->handle = old_page_owner->handle;
242
243 /*
244 * We don't clear the bit on the oldpage as it's going to be freed
245 * after migration. Until then, the info can be useful in case of
246 * a bug, and the overal stats will be off a bit only temporarily.
247 * Also, migrate_misplaced_transhuge_page() can still fail the
248 * migration and then we want the oldpage to retain the info. But
249 * in that case we also don't need to explicitly clear the info from
250 * the new page, which will be freed.
251 */
252 __set_bit(PAGE_EXT_OWNER, &new_ext->flags);
253}
254
255void pagetypeinfo_showmixedcount_print(struct seq_file *m,
256 pg_data_t *pgdat, struct zone *zone)
257{
258 struct page *page;
259 struct page_ext *page_ext;
260 struct page_owner *page_owner;
261 unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
262 unsigned long end_pfn = pfn + zone->spanned_pages;
263 unsigned long count[MIGRATE_TYPES] = { 0, };
264 int pageblock_mt, page_mt;
265 int i;
266
267 /* Scan block by block. First and last block may be incomplete */
268 pfn = zone->zone_start_pfn;
269
270 /*
271 * Walk the zone in pageblock_nr_pages steps. If a page block spans
272 * a zone boundary, it will be double counted between zones. This does
273 * not matter as the mixed block count will still be correct
274 */
275 for (; pfn < end_pfn; ) {
276 if (!pfn_valid(pfn)) {
277 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
278 continue;
279 }
280
281 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
282 block_end_pfn = min(block_end_pfn, end_pfn);
283
284 page = pfn_to_page(pfn);
285 pageblock_mt = get_pageblock_migratetype(page);
286
287 for (; pfn < block_end_pfn; pfn++) {
288 if (!pfn_valid_within(pfn))
289 continue;
290
291 page = pfn_to_page(pfn);
292
293 if (page_zone(page) != zone)
294 continue;
295
296 if (PageBuddy(page)) {
297 unsigned long freepage_order;
298
299 freepage_order = page_order_unsafe(page);
300 if (freepage_order < MAX_ORDER)
301 pfn += (1UL << freepage_order) - 1;
302 continue;
303 }
304
305 if (PageReserved(page))
306 continue;
307
308 page_ext = lookup_page_ext(page);
309 if (unlikely(!page_ext))
310 continue;
311
312 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
313 continue;
314
315 page_owner = get_page_owner(page_ext);
316 page_mt = gfpflags_to_migratetype(
317 page_owner->gfp_mask);
318 if (pageblock_mt != page_mt) {
319 if (is_migrate_cma(pageblock_mt))
320 count[MIGRATE_MOVABLE]++;
321 else
322 count[pageblock_mt]++;
323
324 pfn = block_end_pfn;
325 break;
326 }
327 pfn += (1UL << page_owner->order) - 1;
328 }
329 }
330
331 /* Print counts */
332 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
333 for (i = 0; i < MIGRATE_TYPES; i++)
334 seq_printf(m, "%12lu ", count[i]);
335 seq_putc(m, '\n');
336}
337
338static ssize_t
339print_page_owner(char __user *buf, size_t count, unsigned long pfn,
340 struct page *page, struct page_owner *page_owner,
341 depot_stack_handle_t handle)
342{
343 int ret;
344 int pageblock_mt, page_mt;
345 char *kbuf;
346 unsigned long entries[PAGE_OWNER_STACK_DEPTH];
347 struct stack_trace trace = {
348 .nr_entries = 0,
349 .entries = entries,
350 .max_entries = PAGE_OWNER_STACK_DEPTH,
351 .skip = 0
352 };
353
354 kbuf = kmalloc(count, GFP_KERNEL);
355 if (!kbuf)
356 return -ENOMEM;
357
358 ret = snprintf(kbuf, count,
359 "Page allocated via order %u, mask %#x(%pGg)\n",
360 page_owner->order, page_owner->gfp_mask,
361 &page_owner->gfp_mask);
362
363 if (ret >= count)
364 goto err;
365
366 /* Print information relevant to grouping pages by mobility */
367 pageblock_mt = get_pageblock_migratetype(page);
368 page_mt = gfpflags_to_migratetype(page_owner->gfp_mask);
369 ret += snprintf(kbuf + ret, count - ret,
370 "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
371 pfn,
372 migratetype_names[page_mt],
373 pfn >> pageblock_order,
374 migratetype_names[pageblock_mt],
375 page->flags, &page->flags);
376
377 if (ret >= count)
378 goto err;
379
380 depot_fetch_stack(handle, &trace);
381 ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
382 if (ret >= count)
383 goto err;
384
385 if (page_owner->last_migrate_reason != -1) {
386 ret += snprintf(kbuf + ret, count - ret,
387 "Page has been migrated, last migrate reason: %s\n",
388 migrate_reason_names[page_owner->last_migrate_reason]);
389 if (ret >= count)
390 goto err;
391 }
392
393 ret += snprintf(kbuf + ret, count - ret, "\n");
394 if (ret >= count)
395 goto err;
396
397 if (copy_to_user(buf, kbuf, ret))
398 ret = -EFAULT;
399
400 kfree(kbuf);
401 return ret;
402
403err:
404 kfree(kbuf);
405 return -ENOMEM;
406}
407
408void __dump_page_owner(struct page *page)
409{
410 struct page_ext *page_ext = lookup_page_ext(page);
411 struct page_owner *page_owner;
412 unsigned long entries[PAGE_OWNER_STACK_DEPTH];
413 struct stack_trace trace = {
414 .nr_entries = 0,
415 .entries = entries,
416 .max_entries = PAGE_OWNER_STACK_DEPTH,
417 .skip = 0
418 };
419 depot_stack_handle_t handle;
420 gfp_t gfp_mask;
421 int mt;
422
423 if (unlikely(!page_ext)) {
424 pr_alert("There is not page extension available.\n");
425 return;
426 }
427
428 page_owner = get_page_owner(page_ext);
429 gfp_mask = page_owner->gfp_mask;
430 mt = gfpflags_to_migratetype(gfp_mask);
431
432 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
433 pr_alert("page_owner info is not active (free page?)\n");
434 return;
435 }
436
437 handle = READ_ONCE(page_owner->handle);
438 if (!handle) {
439 pr_alert("page_owner info is not active (free page?)\n");
440 return;
441 }
442
443 depot_fetch_stack(handle, &trace);
444 pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
445 page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
446 print_stack_trace(&trace, 0);
447
448 if (page_owner->last_migrate_reason != -1)
449 pr_alert("page has been migrated, last migrate reason: %s\n",
450 migrate_reason_names[page_owner->last_migrate_reason]);
451}
452
453static ssize_t
454read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
455{
456 unsigned long pfn;
457 struct page *page;
458 struct page_ext *page_ext;
459 struct page_owner *page_owner;
460 depot_stack_handle_t handle;
461
462 if (!static_branch_unlikely(&page_owner_inited))
463 return -EINVAL;
464
465 page = NULL;
466 pfn = min_low_pfn + *ppos;
467
468 /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
469 while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
470 pfn++;
471
472 drain_all_pages(NULL);
473
474 /* Find an allocated page */
475 for (; pfn < max_pfn; pfn++) {
476 /*
477 * If the new page is in a new MAX_ORDER_NR_PAGES area,
478 * validate the area as existing, skip it if not
479 */
480 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
481 pfn += MAX_ORDER_NR_PAGES - 1;
482 continue;
483 }
484
485 /* Check for holes within a MAX_ORDER area */
486 if (!pfn_valid_within(pfn))
487 continue;
488
489 page = pfn_to_page(pfn);
490 if (PageBuddy(page)) {
491 unsigned long freepage_order = page_order_unsafe(page);
492
493 if (freepage_order < MAX_ORDER)
494 pfn += (1UL << freepage_order) - 1;
495 continue;
496 }
497
498 page_ext = lookup_page_ext(page);
499 if (unlikely(!page_ext))
500 continue;
501
502 /*
503 * Some pages could be missed by concurrent allocation or free,
504 * because we don't hold the zone lock.
505 */
506 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
507 continue;
508
509 page_owner = get_page_owner(page_ext);
510
511 /*
512 * Access to page_ext->handle isn't synchronous so we should
513 * be careful to access it.
514 */
515 handle = READ_ONCE(page_owner->handle);
516 if (!handle)
517 continue;
518
519 /* Record the next PFN to read in the file offset */
520 *ppos = (pfn - min_low_pfn) + 1;
521
522 return print_page_owner(buf, count, pfn, page,
523 page_owner, handle);
524 }
525
526 return 0;
527}
528
529static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
530{
531 unsigned long pfn = zone->zone_start_pfn;
532 unsigned long end_pfn = zone_end_pfn(zone);
533 unsigned long count = 0;
534
535 /*
536 * Walk the zone in pageblock_nr_pages steps. If a page block spans
537 * a zone boundary, it will be double counted between zones. This does
538 * not matter as the mixed block count will still be correct
539 */
540 for (; pfn < end_pfn; ) {
541 unsigned long block_end_pfn;
542
543 if (!pfn_valid(pfn)) {
544 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
545 continue;
546 }
547
548 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
549 block_end_pfn = min(block_end_pfn, end_pfn);
550
551 for (; pfn < block_end_pfn; pfn++) {
552 struct page *page;
553 struct page_ext *page_ext;
554
555 if (!pfn_valid_within(pfn))
556 continue;
557
558 page = pfn_to_page(pfn);
559
560 if (page_zone(page) != zone)
561 continue;
562
563 /*
564 * To avoid having to grab zone->lock, be a little
565 * careful when reading buddy page order. The only
566 * danger is that we skip too much and potentially miss
567 * some early allocated pages, which is better than
568 * heavy lock contention.
569 */
570 if (PageBuddy(page)) {
571 unsigned long order = page_order_unsafe(page);
572
573 if (order > 0 && order < MAX_ORDER)
574 pfn += (1UL << order) - 1;
575 continue;
576 }
577
578 if (PageReserved(page))
579 continue;
580
581 page_ext = lookup_page_ext(page);
582 if (unlikely(!page_ext))
583 continue;
584
585 /* Maybe overlapping zone */
586 if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
587 continue;
588
589 /* Found early allocated page */
590 __set_page_owner_handle(page_ext, early_handle, 0, 0);
591 count++;
592 }
593 cond_resched();
594 }
595
596 pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
597 pgdat->node_id, zone->name, count);
598}
599
600static void init_zones_in_node(pg_data_t *pgdat)
601{
602 struct zone *zone;
603 struct zone *node_zones = pgdat->node_zones;
604
605 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
606 if (!populated_zone(zone))
607 continue;
608
609 init_pages_in_zone(pgdat, zone);
610 }
611}
612
613static void init_early_allocated_pages(void)
614{
615 pg_data_t *pgdat;
616
617 for_each_online_pgdat(pgdat)
618 init_zones_in_node(pgdat);
619}
620
621static const struct file_operations proc_page_owner_operations = {
622 .read = read_page_owner,
623};
624
625static int __init pageowner_init(void)
626{
627 struct dentry *dentry;
628
629 if (!static_branch_unlikely(&page_owner_inited)) {
630 pr_info("page_owner is disabled\n");
631 return 0;
632 }
633
634 dentry = debugfs_create_file("page_owner", S_IRUSR, NULL,
635 NULL, &proc_page_owner_operations);
636
637 return PTR_ERR_OR_ZERO(dentry);
638}
639late_initcall(pageowner_init)
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#include <linux/memcontrol.h>
14#include <linux/sched/clock.h>
15
16#include "internal.h"
17
18/*
19 * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack)
20 * to use off stack temporal storage
21 */
22#define PAGE_OWNER_STACK_DEPTH (16)
23
24struct page_owner {
25 unsigned short order;
26 short last_migrate_reason;
27 gfp_t gfp_mask;
28 depot_stack_handle_t handle;
29 depot_stack_handle_t free_handle;
30 u64 ts_nsec;
31 u64 free_ts_nsec;
32 char comm[TASK_COMM_LEN];
33 pid_t pid;
34 pid_t tgid;
35 pid_t free_pid;
36 pid_t free_tgid;
37};
38
39struct stack {
40 struct stack_record *stack_record;
41 struct stack *next;
42};
43static struct stack dummy_stack;
44static struct stack failure_stack;
45static struct stack *stack_list;
46static DEFINE_SPINLOCK(stack_list_lock);
47
48static bool page_owner_enabled __initdata;
49DEFINE_STATIC_KEY_FALSE(page_owner_inited);
50
51static depot_stack_handle_t dummy_handle;
52static depot_stack_handle_t failure_handle;
53static depot_stack_handle_t early_handle;
54
55static void init_early_allocated_pages(void);
56
57static inline void set_current_in_page_owner(void)
58{
59 /*
60 * Avoid recursion.
61 *
62 * We might need to allocate more memory from page_owner code, so make
63 * sure to signal it in order to avoid recursion.
64 */
65 current->in_page_owner = 1;
66}
67
68static inline void unset_current_in_page_owner(void)
69{
70 current->in_page_owner = 0;
71}
72
73static int __init early_page_owner_param(char *buf)
74{
75 int ret = kstrtobool(buf, &page_owner_enabled);
76
77 if (page_owner_enabled)
78 stack_depot_request_early_init();
79
80 return ret;
81}
82early_param("page_owner", early_page_owner_param);
83
84static __init bool need_page_owner(void)
85{
86 return page_owner_enabled;
87}
88
89static __always_inline depot_stack_handle_t create_dummy_stack(void)
90{
91 unsigned long entries[4];
92 unsigned int nr_entries;
93
94 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
95 return stack_depot_save(entries, nr_entries, GFP_KERNEL);
96}
97
98static noinline void register_dummy_stack(void)
99{
100 dummy_handle = create_dummy_stack();
101}
102
103static noinline void register_failure_stack(void)
104{
105 failure_handle = create_dummy_stack();
106}
107
108static noinline void register_early_stack(void)
109{
110 early_handle = create_dummy_stack();
111}
112
113static __init void init_page_owner(void)
114{
115 if (!page_owner_enabled)
116 return;
117
118 register_dummy_stack();
119 register_failure_stack();
120 register_early_stack();
121 init_early_allocated_pages();
122 /* Initialize dummy and failure stacks and link them to stack_list */
123 dummy_stack.stack_record = __stack_depot_get_stack_record(dummy_handle);
124 failure_stack.stack_record = __stack_depot_get_stack_record(failure_handle);
125 if (dummy_stack.stack_record)
126 refcount_set(&dummy_stack.stack_record->count, 1);
127 if (failure_stack.stack_record)
128 refcount_set(&failure_stack.stack_record->count, 1);
129 dummy_stack.next = &failure_stack;
130 stack_list = &dummy_stack;
131 static_branch_enable(&page_owner_inited);
132}
133
134struct page_ext_operations page_owner_ops = {
135 .size = sizeof(struct page_owner),
136 .need = need_page_owner,
137 .init = init_page_owner,
138 .need_shared_flags = true,
139};
140
141static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
142{
143 return page_ext_data(page_ext, &page_owner_ops);
144}
145
146static noinline depot_stack_handle_t save_stack(gfp_t flags)
147{
148 unsigned long entries[PAGE_OWNER_STACK_DEPTH];
149 depot_stack_handle_t handle;
150 unsigned int nr_entries;
151
152 if (current->in_page_owner)
153 return dummy_handle;
154
155 set_current_in_page_owner();
156 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
157 handle = stack_depot_save(entries, nr_entries, flags);
158 if (!handle)
159 handle = failure_handle;
160 unset_current_in_page_owner();
161
162 return handle;
163}
164
165static void add_stack_record_to_list(struct stack_record *stack_record,
166 gfp_t gfp_mask)
167{
168 unsigned long flags;
169 struct stack *stack;
170
171 set_current_in_page_owner();
172 stack = kmalloc(sizeof(*stack), gfp_nested_mask(gfp_mask));
173 if (!stack) {
174 unset_current_in_page_owner();
175 return;
176 }
177 unset_current_in_page_owner();
178
179 stack->stack_record = stack_record;
180 stack->next = NULL;
181
182 spin_lock_irqsave(&stack_list_lock, flags);
183 stack->next = stack_list;
184 /*
185 * This pairs with smp_load_acquire() from function
186 * stack_start(). This guarantees that stack_start()
187 * will see an updated stack_list before starting to
188 * traverse the list.
189 */
190 smp_store_release(&stack_list, stack);
191 spin_unlock_irqrestore(&stack_list_lock, flags);
192}
193
194static void inc_stack_record_count(depot_stack_handle_t handle, gfp_t gfp_mask,
195 int nr_base_pages)
196{
197 struct stack_record *stack_record = __stack_depot_get_stack_record(handle);
198
199 if (!stack_record)
200 return;
201
202 /*
203 * New stack_record's that do not use STACK_DEPOT_FLAG_GET start
204 * with REFCOUNT_SATURATED to catch spurious increments of their
205 * refcount.
206 * Since we do not use STACK_DEPOT_FLAG_GET API, let us
207 * set a refcount of 1 ourselves.
208 */
209 if (refcount_read(&stack_record->count) == REFCOUNT_SATURATED) {
210 int old = REFCOUNT_SATURATED;
211
212 if (atomic_try_cmpxchg_relaxed(&stack_record->count.refs, &old, 1))
213 /* Add the new stack_record to our list */
214 add_stack_record_to_list(stack_record, gfp_mask);
215 }
216 refcount_add(nr_base_pages, &stack_record->count);
217}
218
219static void dec_stack_record_count(depot_stack_handle_t handle,
220 int nr_base_pages)
221{
222 struct stack_record *stack_record = __stack_depot_get_stack_record(handle);
223
224 if (!stack_record)
225 return;
226
227 if (refcount_sub_and_test(nr_base_pages, &stack_record->count))
228 pr_warn("%s: refcount went to 0 for %u handle\n", __func__,
229 handle);
230}
231
232static inline void __update_page_owner_handle(struct page_ext *page_ext,
233 depot_stack_handle_t handle,
234 unsigned short order,
235 gfp_t gfp_mask,
236 short last_migrate_reason, u64 ts_nsec,
237 pid_t pid, pid_t tgid, char *comm)
238{
239 int i;
240 struct page_owner *page_owner;
241
242 for (i = 0; i < (1 << order); i++) {
243 page_owner = get_page_owner(page_ext);
244 page_owner->handle = handle;
245 page_owner->order = order;
246 page_owner->gfp_mask = gfp_mask;
247 page_owner->last_migrate_reason = last_migrate_reason;
248 page_owner->pid = pid;
249 page_owner->tgid = tgid;
250 page_owner->ts_nsec = ts_nsec;
251 strscpy(page_owner->comm, comm,
252 sizeof(page_owner->comm));
253 __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
254 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
255 page_ext = page_ext_next(page_ext);
256 }
257}
258
259static inline void __update_page_owner_free_handle(struct page_ext *page_ext,
260 depot_stack_handle_t handle,
261 unsigned short order,
262 pid_t pid, pid_t tgid,
263 u64 free_ts_nsec)
264{
265 int i;
266 struct page_owner *page_owner;
267
268 for (i = 0; i < (1 << order); i++) {
269 page_owner = get_page_owner(page_ext);
270 /* Only __reset_page_owner() wants to clear the bit */
271 if (handle) {
272 __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
273 page_owner->free_handle = handle;
274 }
275 page_owner->free_ts_nsec = free_ts_nsec;
276 page_owner->free_pid = current->pid;
277 page_owner->free_tgid = current->tgid;
278 page_ext = page_ext_next(page_ext);
279 }
280}
281
282void __reset_page_owner(struct page *page, unsigned short order)
283{
284 struct page_ext *page_ext;
285 depot_stack_handle_t handle;
286 depot_stack_handle_t alloc_handle;
287 struct page_owner *page_owner;
288 u64 free_ts_nsec = local_clock();
289
290 page_ext = page_ext_get(page);
291 if (unlikely(!page_ext))
292 return;
293
294 page_owner = get_page_owner(page_ext);
295 alloc_handle = page_owner->handle;
296
297 handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
298 __update_page_owner_free_handle(page_ext, handle, order, current->pid,
299 current->tgid, free_ts_nsec);
300 page_ext_put(page_ext);
301
302 if (alloc_handle != early_handle)
303 /*
304 * early_handle is being set as a handle for all those
305 * early allocated pages. See init_pages_in_zone().
306 * Since their refcount is not being incremented because
307 * the machinery is not ready yet, we cannot decrement
308 * their refcount either.
309 */
310 dec_stack_record_count(alloc_handle, 1 << order);
311}
312
313noinline void __set_page_owner(struct page *page, unsigned short order,
314 gfp_t gfp_mask)
315{
316 struct page_ext *page_ext;
317 u64 ts_nsec = local_clock();
318 depot_stack_handle_t handle;
319
320 handle = save_stack(gfp_mask);
321
322 page_ext = page_ext_get(page);
323 if (unlikely(!page_ext))
324 return;
325 __update_page_owner_handle(page_ext, handle, order, gfp_mask, -1,
326 ts_nsec, current->pid, current->tgid,
327 current->comm);
328 page_ext_put(page_ext);
329 inc_stack_record_count(handle, gfp_mask, 1 << order);
330}
331
332void __set_page_owner_migrate_reason(struct page *page, int reason)
333{
334 struct page_ext *page_ext = page_ext_get(page);
335 struct page_owner *page_owner;
336
337 if (unlikely(!page_ext))
338 return;
339
340 page_owner = get_page_owner(page_ext);
341 page_owner->last_migrate_reason = reason;
342 page_ext_put(page_ext);
343}
344
345void __split_page_owner(struct page *page, int old_order, int new_order)
346{
347 int i;
348 struct page_ext *page_ext = page_ext_get(page);
349 struct page_owner *page_owner;
350
351 if (unlikely(!page_ext))
352 return;
353
354 for (i = 0; i < (1 << old_order); i++) {
355 page_owner = get_page_owner(page_ext);
356 page_owner->order = new_order;
357 page_ext = page_ext_next(page_ext);
358 }
359 page_ext_put(page_ext);
360}
361
362void __folio_copy_owner(struct folio *newfolio, struct folio *old)
363{
364 int i;
365 struct page_ext *old_ext;
366 struct page_ext *new_ext;
367 struct page_owner *old_page_owner;
368 struct page_owner *new_page_owner;
369 depot_stack_handle_t migrate_handle;
370
371 old_ext = page_ext_get(&old->page);
372 if (unlikely(!old_ext))
373 return;
374
375 new_ext = page_ext_get(&newfolio->page);
376 if (unlikely(!new_ext)) {
377 page_ext_put(old_ext);
378 return;
379 }
380
381 old_page_owner = get_page_owner(old_ext);
382 new_page_owner = get_page_owner(new_ext);
383 migrate_handle = new_page_owner->handle;
384 __update_page_owner_handle(new_ext, old_page_owner->handle,
385 old_page_owner->order, old_page_owner->gfp_mask,
386 old_page_owner->last_migrate_reason,
387 old_page_owner->ts_nsec, old_page_owner->pid,
388 old_page_owner->tgid, old_page_owner->comm);
389 /*
390 * Do not proactively clear PAGE_EXT_OWNER{_ALLOCATED} bits as the folio
391 * will be freed after migration. Keep them until then as they may be
392 * useful.
393 */
394 __update_page_owner_free_handle(new_ext, 0, old_page_owner->order,
395 old_page_owner->free_pid,
396 old_page_owner->free_tgid,
397 old_page_owner->free_ts_nsec);
398 /*
399 * We linked the original stack to the new folio, we need to do the same
400 * for the new one and the old folio otherwise there will be an imbalance
401 * when subtracting those pages from the stack.
402 */
403 for (i = 0; i < (1 << new_page_owner->order); i++) {
404 old_page_owner->handle = migrate_handle;
405 old_ext = page_ext_next(old_ext);
406 old_page_owner = get_page_owner(old_ext);
407 }
408
409 page_ext_put(new_ext);
410 page_ext_put(old_ext);
411}
412
413void pagetypeinfo_showmixedcount_print(struct seq_file *m,
414 pg_data_t *pgdat, struct zone *zone)
415{
416 struct page *page;
417 struct page_ext *page_ext;
418 struct page_owner *page_owner;
419 unsigned long pfn, block_end_pfn;
420 unsigned long end_pfn = zone_end_pfn(zone);
421 unsigned long count[MIGRATE_TYPES] = { 0, };
422 int pageblock_mt, page_mt;
423 int i;
424
425 /* Scan block by block. First and last block may be incomplete */
426 pfn = zone->zone_start_pfn;
427
428 /*
429 * Walk the zone in pageblock_nr_pages steps. If a page block spans
430 * a zone boundary, it will be double counted between zones. This does
431 * not matter as the mixed block count will still be correct
432 */
433 for (; pfn < end_pfn; ) {
434 page = pfn_to_online_page(pfn);
435 if (!page) {
436 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
437 continue;
438 }
439
440 block_end_pfn = pageblock_end_pfn(pfn);
441 block_end_pfn = min(block_end_pfn, end_pfn);
442
443 pageblock_mt = get_pageblock_migratetype(page);
444
445 for (; pfn < block_end_pfn; pfn++) {
446 /* The pageblock is online, no need to recheck. */
447 page = pfn_to_page(pfn);
448
449 if (page_zone(page) != zone)
450 continue;
451
452 if (PageBuddy(page)) {
453 unsigned long freepage_order;
454
455 freepage_order = buddy_order_unsafe(page);
456 if (freepage_order <= MAX_PAGE_ORDER)
457 pfn += (1UL << freepage_order) - 1;
458 continue;
459 }
460
461 if (PageReserved(page))
462 continue;
463
464 page_ext = page_ext_get(page);
465 if (unlikely(!page_ext))
466 continue;
467
468 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
469 goto ext_put_continue;
470
471 page_owner = get_page_owner(page_ext);
472 page_mt = gfp_migratetype(page_owner->gfp_mask);
473 if (pageblock_mt != page_mt) {
474 if (is_migrate_cma(pageblock_mt))
475 count[MIGRATE_MOVABLE]++;
476 else
477 count[pageblock_mt]++;
478
479 pfn = block_end_pfn;
480 page_ext_put(page_ext);
481 break;
482 }
483 pfn += (1UL << page_owner->order) - 1;
484ext_put_continue:
485 page_ext_put(page_ext);
486 }
487 }
488
489 /* Print counts */
490 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
491 for (i = 0; i < MIGRATE_TYPES; i++)
492 seq_printf(m, "%12lu ", count[i]);
493 seq_putc(m, '\n');
494}
495
496/*
497 * Looking for memcg information and print it out
498 */
499static inline int print_page_owner_memcg(char *kbuf, size_t count, int ret,
500 struct page *page)
501{
502#ifdef CONFIG_MEMCG
503 unsigned long memcg_data;
504 struct mem_cgroup *memcg;
505 bool online;
506 char name[80];
507
508 rcu_read_lock();
509 memcg_data = READ_ONCE(page->memcg_data);
510 if (!memcg_data)
511 goto out_unlock;
512
513 if (memcg_data & MEMCG_DATA_OBJEXTS)
514 ret += scnprintf(kbuf + ret, count - ret,
515 "Slab cache page\n");
516
517 memcg = page_memcg_check(page);
518 if (!memcg)
519 goto out_unlock;
520
521 online = (memcg->css.flags & CSS_ONLINE);
522 cgroup_name(memcg->css.cgroup, name, sizeof(name));
523 ret += scnprintf(kbuf + ret, count - ret,
524 "Charged %sto %smemcg %s\n",
525 PageMemcgKmem(page) ? "(via objcg) " : "",
526 online ? "" : "offline ",
527 name);
528out_unlock:
529 rcu_read_unlock();
530#endif /* CONFIG_MEMCG */
531
532 return ret;
533}
534
535static ssize_t
536print_page_owner(char __user *buf, size_t count, unsigned long pfn,
537 struct page *page, struct page_owner *page_owner,
538 depot_stack_handle_t handle)
539{
540 int ret, pageblock_mt, page_mt;
541 char *kbuf;
542
543 count = min_t(size_t, count, PAGE_SIZE);
544 kbuf = kmalloc(count, GFP_KERNEL);
545 if (!kbuf)
546 return -ENOMEM;
547
548 ret = scnprintf(kbuf, count,
549 "Page allocated via order %u, mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu ns\n",
550 page_owner->order, page_owner->gfp_mask,
551 &page_owner->gfp_mask, page_owner->pid,
552 page_owner->tgid, page_owner->comm,
553 page_owner->ts_nsec);
554
555 /* Print information relevant to grouping pages by mobility */
556 pageblock_mt = get_pageblock_migratetype(page);
557 page_mt = gfp_migratetype(page_owner->gfp_mask);
558 ret += scnprintf(kbuf + ret, count - ret,
559 "PFN 0x%lx type %s Block %lu type %s Flags %pGp\n",
560 pfn,
561 migratetype_names[page_mt],
562 pfn >> pageblock_order,
563 migratetype_names[pageblock_mt],
564 &page->flags);
565
566 ret += stack_depot_snprint(handle, kbuf + ret, count - ret, 0);
567 if (ret >= count)
568 goto err;
569
570 if (page_owner->last_migrate_reason != -1) {
571 ret += scnprintf(kbuf + ret, count - ret,
572 "Page has been migrated, last migrate reason: %s\n",
573 migrate_reason_names[page_owner->last_migrate_reason]);
574 }
575
576 ret = print_page_owner_memcg(kbuf, count, ret, page);
577
578 ret += snprintf(kbuf + ret, count - ret, "\n");
579 if (ret >= count)
580 goto err;
581
582 if (copy_to_user(buf, kbuf, ret))
583 ret = -EFAULT;
584
585 kfree(kbuf);
586 return ret;
587
588err:
589 kfree(kbuf);
590 return -ENOMEM;
591}
592
593void __dump_page_owner(const struct page *page)
594{
595 struct page_ext *page_ext = page_ext_get((void *)page);
596 struct page_owner *page_owner;
597 depot_stack_handle_t handle;
598 gfp_t gfp_mask;
599 int mt;
600
601 if (unlikely(!page_ext)) {
602 pr_alert("There is not page extension available.\n");
603 return;
604 }
605
606 page_owner = get_page_owner(page_ext);
607 gfp_mask = page_owner->gfp_mask;
608 mt = gfp_migratetype(gfp_mask);
609
610 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
611 pr_alert("page_owner info is not present (never set?)\n");
612 page_ext_put(page_ext);
613 return;
614 }
615
616 if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
617 pr_alert("page_owner tracks the page as allocated\n");
618 else
619 pr_alert("page_owner tracks the page as freed\n");
620
621 pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, tgid %d (%s), ts %llu, free_ts %llu\n",
622 page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask,
623 page_owner->pid, page_owner->tgid, page_owner->comm,
624 page_owner->ts_nsec, page_owner->free_ts_nsec);
625
626 handle = READ_ONCE(page_owner->handle);
627 if (!handle)
628 pr_alert("page_owner allocation stack trace missing\n");
629 else
630 stack_depot_print(handle);
631
632 handle = READ_ONCE(page_owner->free_handle);
633 if (!handle) {
634 pr_alert("page_owner free stack trace missing\n");
635 } else {
636 pr_alert("page last free pid %d tgid %d stack trace:\n",
637 page_owner->free_pid, page_owner->free_tgid);
638 stack_depot_print(handle);
639 }
640
641 if (page_owner->last_migrate_reason != -1)
642 pr_alert("page has been migrated, last migrate reason: %s\n",
643 migrate_reason_names[page_owner->last_migrate_reason]);
644 page_ext_put(page_ext);
645}
646
647static ssize_t
648read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
649{
650 unsigned long pfn;
651 struct page *page;
652 struct page_ext *page_ext;
653 struct page_owner *page_owner;
654 depot_stack_handle_t handle;
655
656 if (!static_branch_unlikely(&page_owner_inited))
657 return -EINVAL;
658
659 page = NULL;
660 if (*ppos == 0)
661 pfn = min_low_pfn;
662 else
663 pfn = *ppos;
664 /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
665 while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
666 pfn++;
667
668 /* Find an allocated page */
669 for (; pfn < max_pfn; pfn++) {
670 /*
671 * This temporary page_owner is required so
672 * that we can avoid the context switches while holding
673 * the rcu lock and copying the page owner information to
674 * user through copy_to_user() or GFP_KERNEL allocations.
675 */
676 struct page_owner page_owner_tmp;
677
678 /*
679 * If the new page is in a new MAX_ORDER_NR_PAGES area,
680 * validate the area as existing, skip it if not
681 */
682 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
683 pfn += MAX_ORDER_NR_PAGES - 1;
684 continue;
685 }
686
687 page = pfn_to_page(pfn);
688 if (PageBuddy(page)) {
689 unsigned long freepage_order = buddy_order_unsafe(page);
690
691 if (freepage_order <= MAX_PAGE_ORDER)
692 pfn += (1UL << freepage_order) - 1;
693 continue;
694 }
695
696 page_ext = page_ext_get(page);
697 if (unlikely(!page_ext))
698 continue;
699
700 /*
701 * Some pages could be missed by concurrent allocation or free,
702 * because we don't hold the zone lock.
703 */
704 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
705 goto ext_put_continue;
706
707 /*
708 * Although we do have the info about past allocation of free
709 * pages, it's not relevant for current memory usage.
710 */
711 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
712 goto ext_put_continue;
713
714 page_owner = get_page_owner(page_ext);
715
716 /*
717 * Don't print "tail" pages of high-order allocations as that
718 * would inflate the stats.
719 */
720 if (!IS_ALIGNED(pfn, 1 << page_owner->order))
721 goto ext_put_continue;
722
723 /*
724 * Access to page_ext->handle isn't synchronous so we should
725 * be careful to access it.
726 */
727 handle = READ_ONCE(page_owner->handle);
728 if (!handle)
729 goto ext_put_continue;
730
731 /* Record the next PFN to read in the file offset */
732 *ppos = pfn + 1;
733
734 page_owner_tmp = *page_owner;
735 page_ext_put(page_ext);
736 return print_page_owner(buf, count, pfn, page,
737 &page_owner_tmp, handle);
738ext_put_continue:
739 page_ext_put(page_ext);
740 }
741
742 return 0;
743}
744
745static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig)
746{
747 switch (orig) {
748 case SEEK_SET:
749 file->f_pos = offset;
750 break;
751 case SEEK_CUR:
752 file->f_pos += offset;
753 break;
754 default:
755 return -EINVAL;
756 }
757 return file->f_pos;
758}
759
760static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
761{
762 unsigned long pfn = zone->zone_start_pfn;
763 unsigned long end_pfn = zone_end_pfn(zone);
764 unsigned long count = 0;
765
766 /*
767 * Walk the zone in pageblock_nr_pages steps. If a page block spans
768 * a zone boundary, it will be double counted between zones. This does
769 * not matter as the mixed block count will still be correct
770 */
771 for (; pfn < end_pfn; ) {
772 unsigned long block_end_pfn;
773
774 if (!pfn_valid(pfn)) {
775 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
776 continue;
777 }
778
779 block_end_pfn = pageblock_end_pfn(pfn);
780 block_end_pfn = min(block_end_pfn, end_pfn);
781
782 for (; pfn < block_end_pfn; pfn++) {
783 struct page *page = pfn_to_page(pfn);
784 struct page_ext *page_ext;
785
786 if (page_zone(page) != zone)
787 continue;
788
789 /*
790 * To avoid having to grab zone->lock, be a little
791 * careful when reading buddy page order. The only
792 * danger is that we skip too much and potentially miss
793 * some early allocated pages, which is better than
794 * heavy lock contention.
795 */
796 if (PageBuddy(page)) {
797 unsigned long order = buddy_order_unsafe(page);
798
799 if (order > 0 && order <= MAX_PAGE_ORDER)
800 pfn += (1UL << order) - 1;
801 continue;
802 }
803
804 if (PageReserved(page))
805 continue;
806
807 page_ext = page_ext_get(page);
808 if (unlikely(!page_ext))
809 continue;
810
811 /* Maybe overlapping zone */
812 if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
813 goto ext_put_continue;
814
815 /* Found early allocated page */
816 __update_page_owner_handle(page_ext, early_handle, 0, 0,
817 -1, local_clock(), current->pid,
818 current->tgid, current->comm);
819 count++;
820ext_put_continue:
821 page_ext_put(page_ext);
822 }
823 cond_resched();
824 }
825
826 pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
827 pgdat->node_id, zone->name, count);
828}
829
830static void init_zones_in_node(pg_data_t *pgdat)
831{
832 struct zone *zone;
833 struct zone *node_zones = pgdat->node_zones;
834
835 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
836 if (!populated_zone(zone))
837 continue;
838
839 init_pages_in_zone(pgdat, zone);
840 }
841}
842
843static void init_early_allocated_pages(void)
844{
845 pg_data_t *pgdat;
846
847 for_each_online_pgdat(pgdat)
848 init_zones_in_node(pgdat);
849}
850
851static const struct file_operations proc_page_owner_operations = {
852 .read = read_page_owner,
853 .llseek = lseek_page_owner,
854};
855
856static void *stack_start(struct seq_file *m, loff_t *ppos)
857{
858 struct stack *stack;
859
860 if (*ppos == -1UL)
861 return NULL;
862
863 if (!*ppos) {
864 /*
865 * This pairs with smp_store_release() from function
866 * add_stack_record_to_list(), so we get a consistent
867 * value of stack_list.
868 */
869 stack = smp_load_acquire(&stack_list);
870 m->private = stack;
871 } else {
872 stack = m->private;
873 }
874
875 return stack;
876}
877
878static void *stack_next(struct seq_file *m, void *v, loff_t *ppos)
879{
880 struct stack *stack = v;
881
882 stack = stack->next;
883 *ppos = stack ? *ppos + 1 : -1UL;
884 m->private = stack;
885
886 return stack;
887}
888
889static unsigned long page_owner_pages_threshold;
890
891static int stack_print(struct seq_file *m, void *v)
892{
893 int i, nr_base_pages;
894 struct stack *stack = v;
895 unsigned long *entries;
896 unsigned long nr_entries;
897 struct stack_record *stack_record = stack->stack_record;
898
899 if (!stack->stack_record)
900 return 0;
901
902 nr_entries = stack_record->size;
903 entries = stack_record->entries;
904 nr_base_pages = refcount_read(&stack_record->count) - 1;
905
906 if (nr_base_pages < 1 || nr_base_pages < page_owner_pages_threshold)
907 return 0;
908
909 for (i = 0; i < nr_entries; i++)
910 seq_printf(m, " %pS\n", (void *)entries[i]);
911 seq_printf(m, "nr_base_pages: %d\n\n", nr_base_pages);
912
913 return 0;
914}
915
916static void stack_stop(struct seq_file *m, void *v)
917{
918}
919
920static const struct seq_operations page_owner_stack_op = {
921 .start = stack_start,
922 .next = stack_next,
923 .stop = stack_stop,
924 .show = stack_print
925};
926
927static int page_owner_stack_open(struct inode *inode, struct file *file)
928{
929 return seq_open_private(file, &page_owner_stack_op, 0);
930}
931
932static const struct file_operations page_owner_stack_operations = {
933 .open = page_owner_stack_open,
934 .read = seq_read,
935 .llseek = seq_lseek,
936 .release = seq_release,
937};
938
939static int page_owner_threshold_get(void *data, u64 *val)
940{
941 *val = READ_ONCE(page_owner_pages_threshold);
942 return 0;
943}
944
945static int page_owner_threshold_set(void *data, u64 val)
946{
947 WRITE_ONCE(page_owner_pages_threshold, val);
948 return 0;
949}
950
951DEFINE_SIMPLE_ATTRIBUTE(proc_page_owner_threshold, &page_owner_threshold_get,
952 &page_owner_threshold_set, "%llu");
953
954
955static int __init pageowner_init(void)
956{
957 struct dentry *dir;
958
959 if (!static_branch_unlikely(&page_owner_inited)) {
960 pr_info("page_owner is disabled\n");
961 return 0;
962 }
963
964 debugfs_create_file("page_owner", 0400, NULL, NULL,
965 &proc_page_owner_operations);
966 dir = debugfs_create_dir("page_owner_stacks", NULL);
967 debugfs_create_file("show_stacks", 0400, dir, NULL,
968 &page_owner_stack_operations);
969 debugfs_create_file("count_threshold", 0600, dir, NULL,
970 &proc_page_owner_threshold);
971
972 return 0;
973}
974late_initcall(pageowner_init)