Loading...
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
22struct page_owner {
23 unsigned short order;
24 short last_migrate_reason;
25 gfp_t gfp_mask;
26 depot_stack_handle_t handle;
27 depot_stack_handle_t free_handle;
28};
29
30static bool page_owner_enabled = false;
31DEFINE_STATIC_KEY_FALSE(page_owner_inited);
32
33static depot_stack_handle_t dummy_handle;
34static depot_stack_handle_t failure_handle;
35static depot_stack_handle_t early_handle;
36
37static void init_early_allocated_pages(void);
38
39static int __init early_page_owner_param(char *buf)
40{
41 if (!buf)
42 return -EINVAL;
43
44 if (strcmp(buf, "on") == 0)
45 page_owner_enabled = true;
46
47 return 0;
48}
49early_param("page_owner", early_page_owner_param);
50
51static bool need_page_owner(void)
52{
53 return page_owner_enabled;
54}
55
56static __always_inline depot_stack_handle_t create_dummy_stack(void)
57{
58 unsigned long entries[4];
59 unsigned int nr_entries;
60
61 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
62 return stack_depot_save(entries, nr_entries, GFP_KERNEL);
63}
64
65static noinline void register_dummy_stack(void)
66{
67 dummy_handle = create_dummy_stack();
68}
69
70static noinline void register_failure_stack(void)
71{
72 failure_handle = create_dummy_stack();
73}
74
75static noinline void register_early_stack(void)
76{
77 early_handle = create_dummy_stack();
78}
79
80static void init_page_owner(void)
81{
82 if (!page_owner_enabled)
83 return;
84
85 register_dummy_stack();
86 register_failure_stack();
87 register_early_stack();
88 static_branch_enable(&page_owner_inited);
89 init_early_allocated_pages();
90}
91
92struct page_ext_operations page_owner_ops = {
93 .size = sizeof(struct page_owner),
94 .need = need_page_owner,
95 .init = init_page_owner,
96};
97
98static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
99{
100 return (void *)page_ext + page_owner_ops.offset;
101}
102
103static inline bool check_recursive_alloc(unsigned long *entries,
104 unsigned int nr_entries,
105 unsigned long ip)
106{
107 unsigned int i;
108
109 for (i = 0; i < nr_entries; i++) {
110 if (entries[i] == ip)
111 return true;
112 }
113 return false;
114}
115
116static noinline depot_stack_handle_t save_stack(gfp_t flags)
117{
118 unsigned long entries[PAGE_OWNER_STACK_DEPTH];
119 depot_stack_handle_t handle;
120 unsigned int nr_entries;
121
122 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
123
124 /*
125 * We need to check recursion here because our request to
126 * stackdepot could trigger memory allocation to save new
127 * entry. New memory allocation would reach here and call
128 * stack_depot_save_entries() again if we don't catch it. There is
129 * still not enough memory in stackdepot so it would try to
130 * allocate memory again and loop forever.
131 */
132 if (check_recursive_alloc(entries, nr_entries, _RET_IP_))
133 return dummy_handle;
134
135 handle = stack_depot_save(entries, nr_entries, flags);
136 if (!handle)
137 handle = failure_handle;
138
139 return handle;
140}
141
142void __reset_page_owner(struct page *page, unsigned int order)
143{
144 int i;
145 struct page_ext *page_ext;
146 depot_stack_handle_t handle = 0;
147 struct page_owner *page_owner;
148
149 handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
150
151 page_ext = lookup_page_ext(page);
152 if (unlikely(!page_ext))
153 return;
154 for (i = 0; i < (1 << order); i++) {
155 __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
156 page_owner = get_page_owner(page_ext);
157 page_owner->free_handle = handle;
158 page_ext = page_ext_next(page_ext);
159 }
160}
161
162static inline void __set_page_owner_handle(struct page *page,
163 struct page_ext *page_ext, depot_stack_handle_t handle,
164 unsigned int order, gfp_t gfp_mask)
165{
166 struct page_owner *page_owner;
167 int i;
168
169 for (i = 0; i < (1 << order); i++) {
170 page_owner = get_page_owner(page_ext);
171 page_owner->handle = handle;
172 page_owner->order = order;
173 page_owner->gfp_mask = gfp_mask;
174 page_owner->last_migrate_reason = -1;
175 __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
176 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
177
178 page_ext = page_ext_next(page_ext);
179 }
180}
181
182noinline void __set_page_owner(struct page *page, unsigned int order,
183 gfp_t gfp_mask)
184{
185 struct page_ext *page_ext = lookup_page_ext(page);
186 depot_stack_handle_t handle;
187
188 if (unlikely(!page_ext))
189 return;
190
191 handle = save_stack(gfp_mask);
192 __set_page_owner_handle(page, page_ext, handle, order, gfp_mask);
193}
194
195void __set_page_owner_migrate_reason(struct page *page, int reason)
196{
197 struct page_ext *page_ext = lookup_page_ext(page);
198 struct page_owner *page_owner;
199
200 if (unlikely(!page_ext))
201 return;
202
203 page_owner = get_page_owner(page_ext);
204 page_owner->last_migrate_reason = reason;
205}
206
207void __split_page_owner(struct page *page, unsigned int order)
208{
209 int i;
210 struct page_ext *page_ext = lookup_page_ext(page);
211 struct page_owner *page_owner;
212
213 if (unlikely(!page_ext))
214 return;
215
216 for (i = 0; i < (1 << order); i++) {
217 page_owner = get_page_owner(page_ext);
218 page_owner->order = 0;
219 page_ext = page_ext_next(page_ext);
220 }
221}
222
223void __copy_page_owner(struct page *oldpage, struct page *newpage)
224{
225 struct page_ext *old_ext = lookup_page_ext(oldpage);
226 struct page_ext *new_ext = lookup_page_ext(newpage);
227 struct page_owner *old_page_owner, *new_page_owner;
228
229 if (unlikely(!old_ext || !new_ext))
230 return;
231
232 old_page_owner = get_page_owner(old_ext);
233 new_page_owner = get_page_owner(new_ext);
234 new_page_owner->order = old_page_owner->order;
235 new_page_owner->gfp_mask = old_page_owner->gfp_mask;
236 new_page_owner->last_migrate_reason =
237 old_page_owner->last_migrate_reason;
238 new_page_owner->handle = old_page_owner->handle;
239
240 /*
241 * We don't clear the bit on the oldpage as it's going to be freed
242 * after migration. Until then, the info can be useful in case of
243 * a bug, and the overal stats will be off a bit only temporarily.
244 * Also, migrate_misplaced_transhuge_page() can still fail the
245 * migration and then we want the oldpage to retain the info. But
246 * in that case we also don't need to explicitly clear the info from
247 * the new page, which will be freed.
248 */
249 __set_bit(PAGE_EXT_OWNER, &new_ext->flags);
250 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &new_ext->flags);
251}
252
253void pagetypeinfo_showmixedcount_print(struct seq_file *m,
254 pg_data_t *pgdat, struct zone *zone)
255{
256 struct page *page;
257 struct page_ext *page_ext;
258 struct page_owner *page_owner;
259 unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
260 unsigned long end_pfn = pfn + zone->spanned_pages;
261 unsigned long count[MIGRATE_TYPES] = { 0, };
262 int pageblock_mt, page_mt;
263 int i;
264
265 /* Scan block by block. First and last block may be incomplete */
266 pfn = zone->zone_start_pfn;
267
268 /*
269 * Walk the zone in pageblock_nr_pages steps. If a page block spans
270 * a zone boundary, it will be double counted between zones. This does
271 * not matter as the mixed block count will still be correct
272 */
273 for (; pfn < end_pfn; ) {
274 page = pfn_to_online_page(pfn);
275 if (!page) {
276 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
277 continue;
278 }
279
280 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
281 block_end_pfn = min(block_end_pfn, end_pfn);
282
283 pageblock_mt = get_pageblock_migratetype(page);
284
285 for (; pfn < block_end_pfn; pfn++) {
286 if (!pfn_valid_within(pfn))
287 continue;
288
289 /* The pageblock is online, no need to recheck. */
290 page = pfn_to_page(pfn);
291
292 if (page_zone(page) != zone)
293 continue;
294
295 if (PageBuddy(page)) {
296 unsigned long freepage_order;
297
298 freepage_order = page_order_unsafe(page);
299 if (freepage_order < MAX_ORDER)
300 pfn += (1UL << freepage_order) - 1;
301 continue;
302 }
303
304 if (PageReserved(page))
305 continue;
306
307 page_ext = lookup_page_ext(page);
308 if (unlikely(!page_ext))
309 continue;
310
311 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
312 continue;
313
314 page_owner = get_page_owner(page_ext);
315 page_mt = gfpflags_to_migratetype(
316 page_owner->gfp_mask);
317 if (pageblock_mt != page_mt) {
318 if (is_migrate_cma(pageblock_mt))
319 count[MIGRATE_MOVABLE]++;
320 else
321 count[pageblock_mt]++;
322
323 pfn = block_end_pfn;
324 break;
325 }
326 pfn += (1UL << page_owner->order) - 1;
327 }
328 }
329
330 /* Print counts */
331 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
332 for (i = 0; i < MIGRATE_TYPES; i++)
333 seq_printf(m, "%12lu ", count[i]);
334 seq_putc(m, '\n');
335}
336
337static ssize_t
338print_page_owner(char __user *buf, size_t count, unsigned long pfn,
339 struct page *page, struct page_owner *page_owner,
340 depot_stack_handle_t handle)
341{
342 int ret, pageblock_mt, page_mt;
343 unsigned long *entries;
344 unsigned int nr_entries;
345 char *kbuf;
346
347 count = min_t(size_t, count, PAGE_SIZE);
348 kbuf = kmalloc(count, GFP_KERNEL);
349 if (!kbuf)
350 return -ENOMEM;
351
352 ret = snprintf(kbuf, count,
353 "Page allocated via order %u, mask %#x(%pGg)\n",
354 page_owner->order, page_owner->gfp_mask,
355 &page_owner->gfp_mask);
356
357 if (ret >= count)
358 goto err;
359
360 /* Print information relevant to grouping pages by mobility */
361 pageblock_mt = get_pageblock_migratetype(page);
362 page_mt = gfpflags_to_migratetype(page_owner->gfp_mask);
363 ret += snprintf(kbuf + ret, count - ret,
364 "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
365 pfn,
366 migratetype_names[page_mt],
367 pfn >> pageblock_order,
368 migratetype_names[pageblock_mt],
369 page->flags, &page->flags);
370
371 if (ret >= count)
372 goto err;
373
374 nr_entries = stack_depot_fetch(handle, &entries);
375 ret += stack_trace_snprint(kbuf + ret, count - ret, entries, nr_entries, 0);
376 if (ret >= count)
377 goto err;
378
379 if (page_owner->last_migrate_reason != -1) {
380 ret += snprintf(kbuf + ret, count - ret,
381 "Page has been migrated, last migrate reason: %s\n",
382 migrate_reason_names[page_owner->last_migrate_reason]);
383 if (ret >= count)
384 goto err;
385 }
386
387 ret += snprintf(kbuf + ret, count - ret, "\n");
388 if (ret >= count)
389 goto err;
390
391 if (copy_to_user(buf, kbuf, ret))
392 ret = -EFAULT;
393
394 kfree(kbuf);
395 return ret;
396
397err:
398 kfree(kbuf);
399 return -ENOMEM;
400}
401
402void __dump_page_owner(struct page *page)
403{
404 struct page_ext *page_ext = lookup_page_ext(page);
405 struct page_owner *page_owner;
406 depot_stack_handle_t handle;
407 unsigned long *entries;
408 unsigned int nr_entries;
409 gfp_t gfp_mask;
410 int mt;
411
412 if (unlikely(!page_ext)) {
413 pr_alert("There is not page extension available.\n");
414 return;
415 }
416
417 page_owner = get_page_owner(page_ext);
418 gfp_mask = page_owner->gfp_mask;
419 mt = gfpflags_to_migratetype(gfp_mask);
420
421 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
422 pr_alert("page_owner info is not present (never set?)\n");
423 return;
424 }
425
426 if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
427 pr_alert("page_owner tracks the page as allocated\n");
428 else
429 pr_alert("page_owner tracks the page as freed\n");
430
431 pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
432 page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
433
434 handle = READ_ONCE(page_owner->handle);
435 if (!handle) {
436 pr_alert("page_owner allocation stack trace missing\n");
437 } else {
438 nr_entries = stack_depot_fetch(handle, &entries);
439 stack_trace_print(entries, nr_entries, 0);
440 }
441
442 handle = READ_ONCE(page_owner->free_handle);
443 if (!handle) {
444 pr_alert("page_owner free stack trace missing\n");
445 } else {
446 nr_entries = stack_depot_fetch(handle, &entries);
447 pr_alert("page last free stack trace:\n");
448 stack_trace_print(entries, nr_entries, 0);
449 }
450
451 if (page_owner->last_migrate_reason != -1)
452 pr_alert("page has been migrated, last migrate reason: %s\n",
453 migrate_reason_names[page_owner->last_migrate_reason]);
454}
455
456static ssize_t
457read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
458{
459 unsigned long pfn;
460 struct page *page;
461 struct page_ext *page_ext;
462 struct page_owner *page_owner;
463 depot_stack_handle_t handle;
464
465 if (!static_branch_unlikely(&page_owner_inited))
466 return -EINVAL;
467
468 page = NULL;
469 pfn = min_low_pfn + *ppos;
470
471 /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
472 while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
473 pfn++;
474
475 drain_all_pages(NULL);
476
477 /* Find an allocated page */
478 for (; pfn < max_pfn; pfn++) {
479 /*
480 * If the new page is in a new MAX_ORDER_NR_PAGES area,
481 * validate the area as existing, skip it if not
482 */
483 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
484 pfn += MAX_ORDER_NR_PAGES - 1;
485 continue;
486 }
487
488 /* Check for holes within a MAX_ORDER area */
489 if (!pfn_valid_within(pfn))
490 continue;
491
492 page = pfn_to_page(pfn);
493 if (PageBuddy(page)) {
494 unsigned long freepage_order = page_order_unsafe(page);
495
496 if (freepage_order < MAX_ORDER)
497 pfn += (1UL << freepage_order) - 1;
498 continue;
499 }
500
501 page_ext = lookup_page_ext(page);
502 if (unlikely(!page_ext))
503 continue;
504
505 /*
506 * Some pages could be missed by concurrent allocation or free,
507 * because we don't hold the zone lock.
508 */
509 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
510 continue;
511
512 /*
513 * Although we do have the info about past allocation of free
514 * pages, it's not relevant for current memory usage.
515 */
516 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
517 continue;
518
519 page_owner = get_page_owner(page_ext);
520
521 /*
522 * Don't print "tail" pages of high-order allocations as that
523 * would inflate the stats.
524 */
525 if (!IS_ALIGNED(pfn, 1 << page_owner->order))
526 continue;
527
528 /*
529 * Access to page_ext->handle isn't synchronous so we should
530 * be careful to access it.
531 */
532 handle = READ_ONCE(page_owner->handle);
533 if (!handle)
534 continue;
535
536 /* Record the next PFN to read in the file offset */
537 *ppos = (pfn - min_low_pfn) + 1;
538
539 return print_page_owner(buf, count, pfn, page,
540 page_owner, handle);
541 }
542
543 return 0;
544}
545
546static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
547{
548 unsigned long pfn = zone->zone_start_pfn;
549 unsigned long end_pfn = zone_end_pfn(zone);
550 unsigned long count = 0;
551
552 /*
553 * Walk the zone in pageblock_nr_pages steps. If a page block spans
554 * a zone boundary, it will be double counted between zones. This does
555 * not matter as the mixed block count will still be correct
556 */
557 for (; pfn < end_pfn; ) {
558 unsigned long block_end_pfn;
559
560 if (!pfn_valid(pfn)) {
561 pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
562 continue;
563 }
564
565 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
566 block_end_pfn = min(block_end_pfn, end_pfn);
567
568 for (; pfn < block_end_pfn; pfn++) {
569 struct page *page;
570 struct page_ext *page_ext;
571
572 if (!pfn_valid_within(pfn))
573 continue;
574
575 page = pfn_to_page(pfn);
576
577 if (page_zone(page) != zone)
578 continue;
579
580 /*
581 * To avoid having to grab zone->lock, be a little
582 * careful when reading buddy page order. The only
583 * danger is that we skip too much and potentially miss
584 * some early allocated pages, which is better than
585 * heavy lock contention.
586 */
587 if (PageBuddy(page)) {
588 unsigned long order = page_order_unsafe(page);
589
590 if (order > 0 && order < MAX_ORDER)
591 pfn += (1UL << order) - 1;
592 continue;
593 }
594
595 if (PageReserved(page))
596 continue;
597
598 page_ext = lookup_page_ext(page);
599 if (unlikely(!page_ext))
600 continue;
601
602 /* Maybe overlapping zone */
603 if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
604 continue;
605
606 /* Found early allocated page */
607 __set_page_owner_handle(page, page_ext, early_handle,
608 0, 0);
609 count++;
610 }
611 cond_resched();
612 }
613
614 pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
615 pgdat->node_id, zone->name, count);
616}
617
618static void init_zones_in_node(pg_data_t *pgdat)
619{
620 struct zone *zone;
621 struct zone *node_zones = pgdat->node_zones;
622
623 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
624 if (!populated_zone(zone))
625 continue;
626
627 init_pages_in_zone(pgdat, zone);
628 }
629}
630
631static void init_early_allocated_pages(void)
632{
633 pg_data_t *pgdat;
634
635 for_each_online_pgdat(pgdat)
636 init_zones_in_node(pgdat);
637}
638
639static const struct file_operations proc_page_owner_operations = {
640 .read = read_page_owner,
641};
642
643static int __init pageowner_init(void)
644{
645 if (!static_branch_unlikely(&page_owner_inited)) {
646 pr_info("page_owner is disabled\n");
647 return 0;
648 }
649
650 debugfs_create_file("page_owner", 0400, NULL, NULL,
651 &proc_page_owner_operations);
652
653 return 0;
654}
655late_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/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)