Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
[linux-2.6-microblaze.git] / mm / page_owner.c
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/sched/clock.h>
14
15 #include "internal.h"
16
17 /*
18  * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack)
19  * to use off stack temporal storage
20  */
21 #define PAGE_OWNER_STACK_DEPTH (16)
22
23 struct page_owner {
24         unsigned short order;
25         short last_migrate_reason;
26         gfp_t gfp_mask;
27         depot_stack_handle_t handle;
28         depot_stack_handle_t free_handle;
29         u64 ts_nsec;
30         pid_t pid;
31 };
32
33 static bool page_owner_enabled = false;
34 DEFINE_STATIC_KEY_FALSE(page_owner_inited);
35
36 static depot_stack_handle_t dummy_handle;
37 static depot_stack_handle_t failure_handle;
38 static depot_stack_handle_t early_handle;
39
40 static void init_early_allocated_pages(void);
41
42 static int __init early_page_owner_param(char *buf)
43 {
44         if (!buf)
45                 return -EINVAL;
46
47         if (strcmp(buf, "on") == 0)
48                 page_owner_enabled = true;
49
50         return 0;
51 }
52 early_param("page_owner", early_page_owner_param);
53
54 static bool need_page_owner(void)
55 {
56         return page_owner_enabled;
57 }
58
59 static __always_inline depot_stack_handle_t create_dummy_stack(void)
60 {
61         unsigned long entries[4];
62         unsigned int nr_entries;
63
64         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0);
65         return stack_depot_save(entries, nr_entries, GFP_KERNEL);
66 }
67
68 static noinline void register_dummy_stack(void)
69 {
70         dummy_handle = create_dummy_stack();
71 }
72
73 static noinline void register_failure_stack(void)
74 {
75         failure_handle = create_dummy_stack();
76 }
77
78 static noinline void register_early_stack(void)
79 {
80         early_handle = create_dummy_stack();
81 }
82
83 static void init_page_owner(void)
84 {
85         if (!page_owner_enabled)
86                 return;
87
88         register_dummy_stack();
89         register_failure_stack();
90         register_early_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 static inline bool check_recursive_alloc(unsigned long *entries,
107                                          unsigned int nr_entries,
108                                          unsigned long ip)
109 {
110         unsigned int i;
111
112         for (i = 0; i < nr_entries; i++) {
113                 if (entries[i] == ip)
114                         return true;
115         }
116         return false;
117 }
118
119 static noinline depot_stack_handle_t save_stack(gfp_t flags)
120 {
121         unsigned long entries[PAGE_OWNER_STACK_DEPTH];
122         depot_stack_handle_t handle;
123         unsigned int nr_entries;
124
125         nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 2);
126
127         /*
128          * We need to check recursion here because our request to
129          * stackdepot could trigger memory allocation to save new
130          * entry. New memory allocation would reach here and call
131          * stack_depot_save_entries() again if we don't catch it. There is
132          * still not enough memory in stackdepot so it would try to
133          * allocate memory again and loop forever.
134          */
135         if (check_recursive_alloc(entries, nr_entries, _RET_IP_))
136                 return dummy_handle;
137
138         handle = stack_depot_save(entries, nr_entries, flags);
139         if (!handle)
140                 handle = failure_handle;
141
142         return handle;
143 }
144
145 void __reset_page_owner(struct page *page, unsigned int order)
146 {
147         int i;
148         struct page_ext *page_ext;
149         depot_stack_handle_t handle = 0;
150         struct page_owner *page_owner;
151
152         handle = save_stack(GFP_NOWAIT | __GFP_NOWARN);
153
154         page_ext = lookup_page_ext(page);
155         if (unlikely(!page_ext))
156                 return;
157         for (i = 0; i < (1 << order); i++) {
158                 __clear_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
159                 page_owner = get_page_owner(page_ext);
160                 page_owner->free_handle = handle;
161                 page_ext = page_ext_next(page_ext);
162         }
163 }
164
165 static inline void __set_page_owner_handle(struct page *page,
166         struct page_ext *page_ext, depot_stack_handle_t handle,
167         unsigned int order, gfp_t gfp_mask)
168 {
169         struct page_owner *page_owner;
170         int i;
171
172         for (i = 0; i < (1 << order); i++) {
173                 page_owner = get_page_owner(page_ext);
174                 page_owner->handle = handle;
175                 page_owner->order = order;
176                 page_owner->gfp_mask = gfp_mask;
177                 page_owner->last_migrate_reason = -1;
178                 page_owner->pid = current->pid;
179                 page_owner->ts_nsec = local_clock();
180                 __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
181                 __set_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags);
182
183                 page_ext = page_ext_next(page_ext);
184         }
185 }
186
187 noinline void __set_page_owner(struct page *page, unsigned int order,
188                                         gfp_t gfp_mask)
189 {
190         struct page_ext *page_ext = lookup_page_ext(page);
191         depot_stack_handle_t handle;
192
193         if (unlikely(!page_ext))
194                 return;
195
196         handle = save_stack(gfp_mask);
197         __set_page_owner_handle(page, page_ext, handle, order, gfp_mask);
198 }
199
200 void __set_page_owner_migrate_reason(struct page *page, int reason)
201 {
202         struct page_ext *page_ext = lookup_page_ext(page);
203         struct page_owner *page_owner;
204
205         if (unlikely(!page_ext))
206                 return;
207
208         page_owner = get_page_owner(page_ext);
209         page_owner->last_migrate_reason = reason;
210 }
211
212 void __split_page_owner(struct page *page, unsigned int nr)
213 {
214         int i;
215         struct page_ext *page_ext = lookup_page_ext(page);
216         struct page_owner *page_owner;
217
218         if (unlikely(!page_ext))
219                 return;
220
221         for (i = 0; i < nr; i++) {
222                 page_owner = get_page_owner(page_ext);
223                 page_owner->order = 0;
224                 page_ext = page_ext_next(page_ext);
225         }
226 }
227
228 void __copy_page_owner(struct page *oldpage, struct page *newpage)
229 {
230         struct page_ext *old_ext = lookup_page_ext(oldpage);
231         struct page_ext *new_ext = lookup_page_ext(newpage);
232         struct page_owner *old_page_owner, *new_page_owner;
233
234         if (unlikely(!old_ext || !new_ext))
235                 return;
236
237         old_page_owner = get_page_owner(old_ext);
238         new_page_owner = get_page_owner(new_ext);
239         new_page_owner->order = old_page_owner->order;
240         new_page_owner->gfp_mask = old_page_owner->gfp_mask;
241         new_page_owner->last_migrate_reason =
242                 old_page_owner->last_migrate_reason;
243         new_page_owner->handle = old_page_owner->handle;
244         new_page_owner->pid = old_page_owner->pid;
245         new_page_owner->ts_nsec = old_page_owner->ts_nsec;
246
247         /*
248          * We don't clear the bit on the oldpage as it's going to be freed
249          * after migration. Until then, the info can be useful in case of
250          * a bug, and the overal stats will be off a bit only temporarily.
251          * Also, migrate_misplaced_transhuge_page() can still fail the
252          * migration and then we want the oldpage to retain the info. But
253          * in that case we also don't need to explicitly clear the info from
254          * the new page, which will be freed.
255          */
256         __set_bit(PAGE_EXT_OWNER, &new_ext->flags);
257         __set_bit(PAGE_EXT_OWNER_ALLOCATED, &new_ext->flags);
258 }
259
260 void pagetypeinfo_showmixedcount_print(struct seq_file *m,
261                                        pg_data_t *pgdat, struct zone *zone)
262 {
263         struct page *page;
264         struct page_ext *page_ext;
265         struct page_owner *page_owner;
266         unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
267         unsigned long end_pfn = pfn + zone->spanned_pages;
268         unsigned long count[MIGRATE_TYPES] = { 0, };
269         int pageblock_mt, page_mt;
270         int i;
271
272         /* Scan block by block. First and last block may be incomplete */
273         pfn = zone->zone_start_pfn;
274
275         /*
276          * Walk the zone in pageblock_nr_pages steps. If a page block spans
277          * a zone boundary, it will be double counted between zones. This does
278          * not matter as the mixed block count will still be correct
279          */
280         for (; pfn < end_pfn; ) {
281                 page = pfn_to_online_page(pfn);
282                 if (!page) {
283                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
284                         continue;
285                 }
286
287                 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
288                 block_end_pfn = min(block_end_pfn, end_pfn);
289
290                 pageblock_mt = get_pageblock_migratetype(page);
291
292                 for (; pfn < block_end_pfn; pfn++) {
293                         if (!pfn_valid_within(pfn))
294                                 continue;
295
296                         /* The pageblock is online, no need to recheck. */
297                         page = pfn_to_page(pfn);
298
299                         if (page_zone(page) != zone)
300                                 continue;
301
302                         if (PageBuddy(page)) {
303                                 unsigned long freepage_order;
304
305                                 freepage_order = buddy_order_unsafe(page);
306                                 if (freepage_order < MAX_ORDER)
307                                         pfn += (1UL << freepage_order) - 1;
308                                 continue;
309                         }
310
311                         if (PageReserved(page))
312                                 continue;
313
314                         page_ext = lookup_page_ext(page);
315                         if (unlikely(!page_ext))
316                                 continue;
317
318                         if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
319                                 continue;
320
321                         page_owner = get_page_owner(page_ext);
322                         page_mt = gfp_migratetype(page_owner->gfp_mask);
323                         if (pageblock_mt != page_mt) {
324                                 if (is_migrate_cma(pageblock_mt))
325                                         count[MIGRATE_MOVABLE]++;
326                                 else
327                                         count[pageblock_mt]++;
328
329                                 pfn = block_end_pfn;
330                                 break;
331                         }
332                         pfn += (1UL << page_owner->order) - 1;
333                 }
334         }
335
336         /* Print counts */
337         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
338         for (i = 0; i < MIGRATE_TYPES; i++)
339                 seq_printf(m, "%12lu ", count[i]);
340         seq_putc(m, '\n');
341 }
342
343 static ssize_t
344 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
345                 struct page *page, struct page_owner *page_owner,
346                 depot_stack_handle_t handle)
347 {
348         int ret, pageblock_mt, page_mt;
349         unsigned long *entries;
350         unsigned int nr_entries;
351         char *kbuf;
352
353         count = min_t(size_t, count, PAGE_SIZE);
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), pid %d, ts %llu ns\n",
360                         page_owner->order, page_owner->gfp_mask,
361                         &page_owner->gfp_mask, page_owner->pid,
362                         page_owner->ts_nsec);
363
364         if (ret >= count)
365                 goto err;
366
367         /* Print information relevant to grouping pages by mobility */
368         pageblock_mt = get_pageblock_migratetype(page);
369         page_mt  = gfp_migratetype(page_owner->gfp_mask);
370         ret += snprintf(kbuf + ret, count - ret,
371                         "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
372                         pfn,
373                         migratetype_names[page_mt],
374                         pfn >> pageblock_order,
375                         migratetype_names[pageblock_mt],
376                         page->flags, &page->flags);
377
378         if (ret >= count)
379                 goto err;
380
381         nr_entries = stack_depot_fetch(handle, &entries);
382         ret += stack_trace_snprint(kbuf + ret, count - ret, entries, nr_entries, 0);
383         if (ret >= count)
384                 goto err;
385
386         if (page_owner->last_migrate_reason != -1) {
387                 ret += snprintf(kbuf + ret, count - ret,
388                         "Page has been migrated, last migrate reason: %s\n",
389                         migrate_reason_names[page_owner->last_migrate_reason]);
390                 if (ret >= count)
391                         goto err;
392         }
393
394         ret += snprintf(kbuf + ret, count - ret, "\n");
395         if (ret >= count)
396                 goto err;
397
398         if (copy_to_user(buf, kbuf, ret))
399                 ret = -EFAULT;
400
401         kfree(kbuf);
402         return ret;
403
404 err:
405         kfree(kbuf);
406         return -ENOMEM;
407 }
408
409 void __dump_page_owner(struct page *page)
410 {
411         struct page_ext *page_ext = lookup_page_ext(page);
412         struct page_owner *page_owner;
413         depot_stack_handle_t handle;
414         unsigned long *entries;
415         unsigned int nr_entries;
416         gfp_t gfp_mask;
417         int mt;
418
419         if (unlikely(!page_ext)) {
420                 pr_alert("There is not page extension available.\n");
421                 return;
422         }
423
424         page_owner = get_page_owner(page_ext);
425         gfp_mask = page_owner->gfp_mask;
426         mt = gfp_migratetype(gfp_mask);
427
428         if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
429                 pr_alert("page_owner info is not present (never set?)\n");
430                 return;
431         }
432
433         if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
434                 pr_alert("page_owner tracks the page as allocated\n");
435         else
436                 pr_alert("page_owner tracks the page as freed\n");
437
438         pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, ts %llu\n",
439                  page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask,
440                  page_owner->pid, page_owner->ts_nsec);
441
442         handle = READ_ONCE(page_owner->handle);
443         if (!handle) {
444                 pr_alert("page_owner allocation stack trace missing\n");
445         } else {
446                 nr_entries = stack_depot_fetch(handle, &entries);
447                 stack_trace_print(entries, nr_entries, 0);
448         }
449
450         handle = READ_ONCE(page_owner->free_handle);
451         if (!handle) {
452                 pr_alert("page_owner free stack trace missing\n");
453         } else {
454                 nr_entries = stack_depot_fetch(handle, &entries);
455                 pr_alert("page last free stack trace:\n");
456                 stack_trace_print(entries, nr_entries, 0);
457         }
458
459         if (page_owner->last_migrate_reason != -1)
460                 pr_alert("page has been migrated, last migrate reason: %s\n",
461                         migrate_reason_names[page_owner->last_migrate_reason]);
462 }
463
464 static ssize_t
465 read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
466 {
467         unsigned long pfn;
468         struct page *page;
469         struct page_ext *page_ext;
470         struct page_owner *page_owner;
471         depot_stack_handle_t handle;
472
473         if (!static_branch_unlikely(&page_owner_inited))
474                 return -EINVAL;
475
476         page = NULL;
477         pfn = min_low_pfn + *ppos;
478
479         /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
480         while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
481                 pfn++;
482
483         drain_all_pages(NULL);
484
485         /* Find an allocated page */
486         for (; pfn < max_pfn; pfn++) {
487                 /*
488                  * If the new page is in a new MAX_ORDER_NR_PAGES area,
489                  * validate the area as existing, skip it if not
490                  */
491                 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
492                         pfn += MAX_ORDER_NR_PAGES - 1;
493                         continue;
494                 }
495
496                 /* Check for holes within a MAX_ORDER area */
497                 if (!pfn_valid_within(pfn))
498                         continue;
499
500                 page = pfn_to_page(pfn);
501                 if (PageBuddy(page)) {
502                         unsigned long freepage_order = buddy_order_unsafe(page);
503
504                         if (freepage_order < MAX_ORDER)
505                                 pfn += (1UL << freepage_order) - 1;
506                         continue;
507                 }
508
509                 page_ext = lookup_page_ext(page);
510                 if (unlikely(!page_ext))
511                         continue;
512
513                 /*
514                  * Some pages could be missed by concurrent allocation or free,
515                  * because we don't hold the zone lock.
516                  */
517                 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
518                         continue;
519
520                 /*
521                  * Although we do have the info about past allocation of free
522                  * pages, it's not relevant for current memory usage.
523                  */
524                 if (!test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
525                         continue;
526
527                 page_owner = get_page_owner(page_ext);
528
529                 /*
530                  * Don't print "tail" pages of high-order allocations as that
531                  * would inflate the stats.
532                  */
533                 if (!IS_ALIGNED(pfn, 1 << page_owner->order))
534                         continue;
535
536                 /*
537                  * Access to page_ext->handle isn't synchronous so we should
538                  * be careful to access it.
539                  */
540                 handle = READ_ONCE(page_owner->handle);
541                 if (!handle)
542                         continue;
543
544                 /* Record the next PFN to read in the file offset */
545                 *ppos = (pfn - min_low_pfn) + 1;
546
547                 return print_page_owner(buf, count, pfn, page,
548                                 page_owner, handle);
549         }
550
551         return 0;
552 }
553
554 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
555 {
556         unsigned long pfn = zone->zone_start_pfn;
557         unsigned long end_pfn = zone_end_pfn(zone);
558         unsigned long count = 0;
559
560         /*
561          * Walk the zone in pageblock_nr_pages steps. If a page block spans
562          * a zone boundary, it will be double counted between zones. This does
563          * not matter as the mixed block count will still be correct
564          */
565         for (; pfn < end_pfn; ) {
566                 unsigned long block_end_pfn;
567
568                 if (!pfn_valid(pfn)) {
569                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
570                         continue;
571                 }
572
573                 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
574                 block_end_pfn = min(block_end_pfn, end_pfn);
575
576                 for (; pfn < block_end_pfn; pfn++) {
577                         struct page *page;
578                         struct page_ext *page_ext;
579
580                         if (!pfn_valid_within(pfn))
581                                 continue;
582
583                         page = pfn_to_page(pfn);
584
585                         if (page_zone(page) != zone)
586                                 continue;
587
588                         /*
589                          * To avoid having to grab zone->lock, be a little
590                          * careful when reading buddy page order. The only
591                          * danger is that we skip too much and potentially miss
592                          * some early allocated pages, which is better than
593                          * heavy lock contention.
594                          */
595                         if (PageBuddy(page)) {
596                                 unsigned long order = buddy_order_unsafe(page);
597
598                                 if (order > 0 && order < MAX_ORDER)
599                                         pfn += (1UL << order) - 1;
600                                 continue;
601                         }
602
603                         if (PageReserved(page))
604                                 continue;
605
606                         page_ext = lookup_page_ext(page);
607                         if (unlikely(!page_ext))
608                                 continue;
609
610                         /* Maybe overlapping zone */
611                         if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
612                                 continue;
613
614                         /* Found early allocated page */
615                         __set_page_owner_handle(page, page_ext, early_handle,
616                                                 0, 0);
617                         count++;
618                 }
619                 cond_resched();
620         }
621
622         pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
623                 pgdat->node_id, zone->name, count);
624 }
625
626 static void init_zones_in_node(pg_data_t *pgdat)
627 {
628         struct zone *zone;
629         struct zone *node_zones = pgdat->node_zones;
630
631         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
632                 if (!populated_zone(zone))
633                         continue;
634
635                 init_pages_in_zone(pgdat, zone);
636         }
637 }
638
639 static void init_early_allocated_pages(void)
640 {
641         pg_data_t *pgdat;
642
643         for_each_online_pgdat(pgdat)
644                 init_zones_in_node(pgdat);
645 }
646
647 static const struct file_operations proc_page_owner_operations = {
648         .read           = read_page_owner,
649 };
650
651 static int __init pageowner_init(void)
652 {
653         if (!static_branch_unlikely(&page_owner_inited)) {
654                 pr_info("page_owner is disabled\n");
655                 return 0;
656         }
657
658         debugfs_create_file("page_owner", 0400, NULL, NULL,
659                             &proc_page_owner_operations);
660
661         return 0;
662 }
663 late_initcall(pageowner_init)