ftrace: Add a ftrace_free_mem() function for modules to use
[linux-2.6-microblaze.git] / mm / page_owner.c
1 #include <linux/debugfs.h>
2 #include <linux/mm.h>
3 #include <linux/slab.h>
4 #include <linux/uaccess.h>
5 #include <linux/bootmem.h>
6 #include <linux/stacktrace.h>
7 #include <linux/page_owner.h>
8 #include <linux/jump_label.h>
9 #include <linux/migrate.h>
10 #include <linux/stackdepot.h>
11 #include <linux/seq_file.h>
12
13 #include "internal.h"
14
15 /*
16  * TODO: teach PAGE_OWNER_STACK_DEPTH (__dump_page_owner and save_stack)
17  * to use off stack temporal storage
18  */
19 #define PAGE_OWNER_STACK_DEPTH (16)
20
21 struct page_owner {
22         unsigned int order;
23         gfp_t gfp_mask;
24         int last_migrate_reason;
25         depot_stack_handle_t handle;
26 };
27
28 static bool page_owner_disabled = true;
29 DEFINE_STATIC_KEY_FALSE(page_owner_inited);
30
31 static depot_stack_handle_t dummy_handle;
32 static depot_stack_handle_t failure_handle;
33 static depot_stack_handle_t early_handle;
34
35 static void init_early_allocated_pages(void);
36
37 static int early_page_owner_param(char *buf)
38 {
39         if (!buf)
40                 return -EINVAL;
41
42         if (strcmp(buf, "on") == 0)
43                 page_owner_disabled = false;
44
45         return 0;
46 }
47 early_param("page_owner", early_page_owner_param);
48
49 static bool need_page_owner(void)
50 {
51         if (page_owner_disabled)
52                 return false;
53
54         return true;
55 }
56
57 static __always_inline depot_stack_handle_t create_dummy_stack(void)
58 {
59         unsigned long entries[4];
60         struct stack_trace dummy;
61
62         dummy.nr_entries = 0;
63         dummy.max_entries = ARRAY_SIZE(entries);
64         dummy.entries = &entries[0];
65         dummy.skip = 0;
66
67         save_stack_trace(&dummy);
68         return depot_save_stack(&dummy, GFP_KERNEL);
69 }
70
71 static noinline void register_dummy_stack(void)
72 {
73         dummy_handle = create_dummy_stack();
74 }
75
76 static noinline void register_failure_stack(void)
77 {
78         failure_handle = create_dummy_stack();
79 }
80
81 static noinline void register_early_stack(void)
82 {
83         early_handle = create_dummy_stack();
84 }
85
86 static void init_page_owner(void)
87 {
88         if (page_owner_disabled)
89                 return;
90
91         register_dummy_stack();
92         register_failure_stack();
93         register_early_stack();
94         static_branch_enable(&page_owner_inited);
95         init_early_allocated_pages();
96 }
97
98 struct page_ext_operations page_owner_ops = {
99         .size = sizeof(struct page_owner),
100         .need = need_page_owner,
101         .init = init_page_owner,
102 };
103
104 static inline struct page_owner *get_page_owner(struct page_ext *page_ext)
105 {
106         return (void *)page_ext + page_owner_ops.offset;
107 }
108
109 void __reset_page_owner(struct page *page, unsigned int order)
110 {
111         int i;
112         struct page_ext *page_ext;
113
114         for (i = 0; i < (1 << order); i++) {
115                 page_ext = lookup_page_ext(page + i);
116                 if (unlikely(!page_ext))
117                         continue;
118                 __clear_bit(PAGE_EXT_OWNER, &page_ext->flags);
119         }
120 }
121
122 static inline bool check_recursive_alloc(struct stack_trace *trace,
123                                         unsigned long ip)
124 {
125         int i, count;
126
127         if (!trace->nr_entries)
128                 return false;
129
130         for (i = 0, count = 0; i < trace->nr_entries; i++) {
131                 if (trace->entries[i] == ip && ++count == 2)
132                         return true;
133         }
134
135         return false;
136 }
137
138 static noinline depot_stack_handle_t save_stack(gfp_t flags)
139 {
140         unsigned long entries[PAGE_OWNER_STACK_DEPTH];
141         struct stack_trace trace = {
142                 .nr_entries = 0,
143                 .entries = entries,
144                 .max_entries = PAGE_OWNER_STACK_DEPTH,
145                 .skip = 2
146         };
147         depot_stack_handle_t handle;
148
149         save_stack_trace(&trace);
150         if (trace.nr_entries != 0 &&
151             trace.entries[trace.nr_entries-1] == ULONG_MAX)
152                 trace.nr_entries--;
153
154         /*
155          * We need to check recursion here because our request to stackdepot
156          * could trigger memory allocation to save new entry. New memory
157          * allocation would reach here and call depot_save_stack() again
158          * if we don't catch it. There is still not enough memory in stackdepot
159          * so it would try to allocate memory again and loop forever.
160          */
161         if (check_recursive_alloc(&trace, _RET_IP_))
162                 return dummy_handle;
163
164         handle = depot_save_stack(&trace, flags);
165         if (!handle)
166                 handle = failure_handle;
167
168         return handle;
169 }
170
171 static inline void __set_page_owner_handle(struct page_ext *page_ext,
172         depot_stack_handle_t handle, unsigned int order, gfp_t gfp_mask)
173 {
174         struct page_owner *page_owner;
175
176         page_owner = get_page_owner(page_ext);
177         page_owner->handle = handle;
178         page_owner->order = order;
179         page_owner->gfp_mask = gfp_mask;
180         page_owner->last_migrate_reason = -1;
181
182         __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
183 }
184
185 noinline void __set_page_owner(struct page *page, unsigned int order,
186                                         gfp_t gfp_mask)
187 {
188         struct page_ext *page_ext = lookup_page_ext(page);
189         depot_stack_handle_t handle;
190
191         if (unlikely(!page_ext))
192                 return;
193
194         handle = save_stack(gfp_mask);
195         __set_page_owner_handle(page_ext, handle, order, gfp_mask);
196 }
197
198 void __set_page_owner_migrate_reason(struct page *page, int reason)
199 {
200         struct page_ext *page_ext = lookup_page_ext(page);
201         struct page_owner *page_owner;
202
203         if (unlikely(!page_ext))
204                 return;
205
206         page_owner = get_page_owner(page_ext);
207         page_owner->last_migrate_reason = reason;
208 }
209
210 void __split_page_owner(struct page *page, unsigned int order)
211 {
212         int i;
213         struct page_ext *page_ext = lookup_page_ext(page);
214         struct page_owner *page_owner;
215
216         if (unlikely(!page_ext))
217                 return;
218
219         page_owner = get_page_owner(page_ext);
220         page_owner->order = 0;
221         for (i = 1; i < (1 << order); i++)
222                 __copy_page_owner(page, page + i);
223 }
224
225 void __copy_page_owner(struct page *oldpage, struct page *newpage)
226 {
227         struct page_ext *old_ext = lookup_page_ext(oldpage);
228         struct page_ext *new_ext = lookup_page_ext(newpage);
229         struct page_owner *old_page_owner, *new_page_owner;
230
231         if (unlikely(!old_ext || !new_ext))
232                 return;
233
234         old_page_owner = get_page_owner(old_ext);
235         new_page_owner = get_page_owner(new_ext);
236         new_page_owner->order = old_page_owner->order;
237         new_page_owner->gfp_mask = old_page_owner->gfp_mask;
238         new_page_owner->last_migrate_reason =
239                 old_page_owner->last_migrate_reason;
240         new_page_owner->handle = old_page_owner->handle;
241
242         /*
243          * We don't clear the bit on the oldpage as it's going to be freed
244          * after migration. Until then, the info can be useful in case of
245          * a bug, and the overal stats will be off a bit only temporarily.
246          * Also, migrate_misplaced_transhuge_page() can still fail the
247          * migration and then we want the oldpage to retain the info. But
248          * in that case we also don't need to explicitly clear the info from
249          * the new page, which will be freed.
250          */
251         __set_bit(PAGE_EXT_OWNER, &new_ext->flags);
252 }
253
254 void pagetypeinfo_showmixedcount_print(struct seq_file *m,
255                                        pg_data_t *pgdat, struct zone *zone)
256 {
257         struct page *page;
258         struct page_ext *page_ext;
259         struct page_owner *page_owner;
260         unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
261         unsigned long end_pfn = pfn + zone->spanned_pages;
262         unsigned long count[MIGRATE_TYPES] = { 0, };
263         int pageblock_mt, page_mt;
264         int i;
265
266         /* Scan block by block. First and last block may be incomplete */
267         pfn = zone->zone_start_pfn;
268
269         /*
270          * Walk the zone in pageblock_nr_pages steps. If a page block spans
271          * a zone boundary, it will be double counted between zones. This does
272          * not matter as the mixed block count will still be correct
273          */
274         for (; pfn < end_pfn; ) {
275                 if (!pfn_valid(pfn)) {
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                 page = pfn_to_page(pfn);
284                 pageblock_mt = get_pageblock_migratetype(page);
285
286                 for (; pfn < block_end_pfn; pfn++) {
287                         if (!pfn_valid_within(pfn))
288                                 continue;
289
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, &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
337 static ssize_t
338 print_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;
343         int pageblock_mt, page_mt;
344         char *kbuf;
345         unsigned long entries[PAGE_OWNER_STACK_DEPTH];
346         struct stack_trace trace = {
347                 .nr_entries = 0,
348                 .entries = entries,
349                 .max_entries = PAGE_OWNER_STACK_DEPTH,
350                 .skip = 0
351         };
352
353         kbuf = kmalloc(count, GFP_KERNEL);
354         if (!kbuf)
355                 return -ENOMEM;
356
357         ret = snprintf(kbuf, count,
358                         "Page allocated via order %u, mask %#x(%pGg)\n",
359                         page_owner->order, page_owner->gfp_mask,
360                         &page_owner->gfp_mask);
361
362         if (ret >= count)
363                 goto err;
364
365         /* Print information relevant to grouping pages by mobility */
366         pageblock_mt = get_pageblock_migratetype(page);
367         page_mt  = gfpflags_to_migratetype(page_owner->gfp_mask);
368         ret += snprintf(kbuf + ret, count - ret,
369                         "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
370                         pfn,
371                         migratetype_names[page_mt],
372                         pfn >> pageblock_order,
373                         migratetype_names[pageblock_mt],
374                         page->flags, &page->flags);
375
376         if (ret >= count)
377                 goto err;
378
379         depot_fetch_stack(handle, &trace);
380         ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
381         if (ret >= count)
382                 goto err;
383
384         if (page_owner->last_migrate_reason != -1) {
385                 ret += snprintf(kbuf + ret, count - ret,
386                         "Page has been migrated, last migrate reason: %s\n",
387                         migrate_reason_names[page_owner->last_migrate_reason]);
388                 if (ret >= count)
389                         goto err;
390         }
391
392         ret += snprintf(kbuf + ret, count - ret, "\n");
393         if (ret >= count)
394                 goto err;
395
396         if (copy_to_user(buf, kbuf, ret))
397                 ret = -EFAULT;
398
399         kfree(kbuf);
400         return ret;
401
402 err:
403         kfree(kbuf);
404         return -ENOMEM;
405 }
406
407 void __dump_page_owner(struct page *page)
408 {
409         struct page_ext *page_ext = lookup_page_ext(page);
410         struct page_owner *page_owner;
411         unsigned long entries[PAGE_OWNER_STACK_DEPTH];
412         struct stack_trace trace = {
413                 .nr_entries = 0,
414                 .entries = entries,
415                 .max_entries = PAGE_OWNER_STACK_DEPTH,
416                 .skip = 0
417         };
418         depot_stack_handle_t handle;
419         gfp_t gfp_mask;
420         int mt;
421
422         if (unlikely(!page_ext)) {
423                 pr_alert("There is not page extension available.\n");
424                 return;
425         }
426
427         page_owner = get_page_owner(page_ext);
428         gfp_mask = page_owner->gfp_mask;
429         mt = gfpflags_to_migratetype(gfp_mask);
430
431         if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
432                 pr_alert("page_owner info is not active (free page?)\n");
433                 return;
434         }
435
436         handle = READ_ONCE(page_owner->handle);
437         if (!handle) {
438                 pr_alert("page_owner info is not active (free page?)\n");
439                 return;
440         }
441
442         depot_fetch_stack(handle, &trace);
443         pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
444                  page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask);
445         print_stack_trace(&trace, 0);
446
447         if (page_owner->last_migrate_reason != -1)
448                 pr_alert("page has been migrated, last migrate reason: %s\n",
449                         migrate_reason_names[page_owner->last_migrate_reason]);
450 }
451
452 static ssize_t
453 read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
454 {
455         unsigned long pfn;
456         struct page *page;
457         struct page_ext *page_ext;
458         struct page_owner *page_owner;
459         depot_stack_handle_t handle;
460
461         if (!static_branch_unlikely(&page_owner_inited))
462                 return -EINVAL;
463
464         page = NULL;
465         pfn = min_low_pfn + *ppos;
466
467         /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
468         while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
469                 pfn++;
470
471         drain_all_pages(NULL);
472
473         /* Find an allocated page */
474         for (; pfn < max_pfn; pfn++) {
475                 /*
476                  * If the new page is in a new MAX_ORDER_NR_PAGES area,
477                  * validate the area as existing, skip it if not
478                  */
479                 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
480                         pfn += MAX_ORDER_NR_PAGES - 1;
481                         continue;
482                 }
483
484                 /* Check for holes within a MAX_ORDER area */
485                 if (!pfn_valid_within(pfn))
486                         continue;
487
488                 page = pfn_to_page(pfn);
489                 if (PageBuddy(page)) {
490                         unsigned long freepage_order = page_order_unsafe(page);
491
492                         if (freepage_order < MAX_ORDER)
493                                 pfn += (1UL << freepage_order) - 1;
494                         continue;
495                 }
496
497                 page_ext = lookup_page_ext(page);
498                 if (unlikely(!page_ext))
499                         continue;
500
501                 /*
502                  * Some pages could be missed by concurrent allocation or free,
503                  * because we don't hold the zone lock.
504                  */
505                 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
506                         continue;
507
508                 page_owner = get_page_owner(page_ext);
509
510                 /*
511                  * Access to page_ext->handle isn't synchronous so we should
512                  * be careful to access it.
513                  */
514                 handle = READ_ONCE(page_owner->handle);
515                 if (!handle)
516                         continue;
517
518                 /* Record the next PFN to read in the file offset */
519                 *ppos = (pfn - min_low_pfn) + 1;
520
521                 return print_page_owner(buf, count, pfn, page,
522                                 page_owner, handle);
523         }
524
525         return 0;
526 }
527
528 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
529 {
530         struct page *page;
531         struct page_ext *page_ext;
532         unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
533         unsigned long end_pfn = pfn + zone->spanned_pages;
534         unsigned long count = 0;
535
536         /* Scan block by block. First and last block may be incomplete */
537         pfn = zone->zone_start_pfn;
538
539         /*
540          * Walk the zone in pageblock_nr_pages steps. If a page block spans
541          * a zone boundary, it will be double counted between zones. This does
542          * not matter as the mixed block count will still be correct
543          */
544         for (; pfn < end_pfn; ) {
545                 if (!pfn_valid(pfn)) {
546                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
547                         continue;
548                 }
549
550                 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
551                 block_end_pfn = min(block_end_pfn, end_pfn);
552
553                 page = pfn_to_page(pfn);
554
555                 for (; pfn < block_end_pfn; pfn++) {
556                         if (!pfn_valid_within(pfn))
557                                 continue;
558
559                         page = pfn_to_page(pfn);
560
561                         if (page_zone(page) != zone)
562                                 continue;
563
564                         /*
565                          * To avoid having to grab zone->lock, be a little
566                          * careful when reading buddy page order. The only
567                          * danger is that we skip too much and potentially miss
568                          * some early allocated pages, which is better than
569                          * heavy lock contention.
570                          */
571                         if (PageBuddy(page)) {
572                                 unsigned long order = page_order_unsafe(page);
573
574                                 if (order > 0 && order < MAX_ORDER)
575                                         pfn += (1UL << order) - 1;
576                                 continue;
577                         }
578
579                         if (PageReserved(page))
580                                 continue;
581
582                         page_ext = lookup_page_ext(page);
583                         if (unlikely(!page_ext))
584                                 continue;
585
586                         /* Maybe overlapping zone */
587                         if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
588                                 continue;
589
590                         /* Found early allocated page */
591                         __set_page_owner_handle(page_ext, early_handle, 0, 0);
592                         count++;
593                 }
594                 cond_resched();
595         }
596
597         pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
598                 pgdat->node_id, zone->name, count);
599 }
600
601 static void init_zones_in_node(pg_data_t *pgdat)
602 {
603         struct zone *zone;
604         struct zone *node_zones = pgdat->node_zones;
605
606         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
607                 if (!populated_zone(zone))
608                         continue;
609
610                 init_pages_in_zone(pgdat, zone);
611         }
612 }
613
614 static void init_early_allocated_pages(void)
615 {
616         pg_data_t *pgdat;
617
618         drain_all_pages(NULL);
619         for_each_online_pgdat(pgdat)
620                 init_zones_in_node(pgdat);
621 }
622
623 static const struct file_operations proc_page_owner_operations = {
624         .read           = read_page_owner,
625 };
626
627 static int __init pageowner_init(void)
628 {
629         struct dentry *dentry;
630
631         if (!static_branch_unlikely(&page_owner_inited)) {
632                 pr_info("page_owner is disabled\n");
633                 return 0;
634         }
635
636         dentry = debugfs_create_file("page_owner", S_IRUSR, NULL,
637                         NULL, &proc_page_owner_operations);
638         if (IS_ERR(dentry))
639                 return PTR_ERR(dentry);
640
641         return 0;
642 }
643 late_initcall(pageowner_init)