Merge tag 'perf-urgent-for-mingo-20160418' of git://git.kernel.org/pub/scm/linux...
[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 "internal.h"
11
12 static bool page_owner_disabled = true;
13 DEFINE_STATIC_KEY_FALSE(page_owner_inited);
14
15 static void init_early_allocated_pages(void);
16
17 static int early_page_owner_param(char *buf)
18 {
19         if (!buf)
20                 return -EINVAL;
21
22         if (strcmp(buf, "on") == 0)
23                 page_owner_disabled = false;
24
25         return 0;
26 }
27 early_param("page_owner", early_page_owner_param);
28
29 static bool need_page_owner(void)
30 {
31         if (page_owner_disabled)
32                 return false;
33
34         return true;
35 }
36
37 static void init_page_owner(void)
38 {
39         if (page_owner_disabled)
40                 return;
41
42         static_branch_enable(&page_owner_inited);
43         init_early_allocated_pages();
44 }
45
46 struct page_ext_operations page_owner_ops = {
47         .need = need_page_owner,
48         .init = init_page_owner,
49 };
50
51 void __reset_page_owner(struct page *page, unsigned int order)
52 {
53         int i;
54         struct page_ext *page_ext;
55
56         for (i = 0; i < (1 << order); i++) {
57                 page_ext = lookup_page_ext(page + i);
58                 __clear_bit(PAGE_EXT_OWNER, &page_ext->flags);
59         }
60 }
61
62 void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask)
63 {
64         struct page_ext *page_ext = lookup_page_ext(page);
65         struct stack_trace trace = {
66                 .nr_entries = 0,
67                 .max_entries = ARRAY_SIZE(page_ext->trace_entries),
68                 .entries = &page_ext->trace_entries[0],
69                 .skip = 3,
70         };
71
72         save_stack_trace(&trace);
73
74         page_ext->order = order;
75         page_ext->gfp_mask = gfp_mask;
76         page_ext->nr_entries = trace.nr_entries;
77         page_ext->last_migrate_reason = -1;
78
79         __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
80 }
81
82 void __set_page_owner_migrate_reason(struct page *page, int reason)
83 {
84         struct page_ext *page_ext = lookup_page_ext(page);
85
86         page_ext->last_migrate_reason = reason;
87 }
88
89 gfp_t __get_page_owner_gfp(struct page *page)
90 {
91         struct page_ext *page_ext = lookup_page_ext(page);
92
93         return page_ext->gfp_mask;
94 }
95
96 void __copy_page_owner(struct page *oldpage, struct page *newpage)
97 {
98         struct page_ext *old_ext = lookup_page_ext(oldpage);
99         struct page_ext *new_ext = lookup_page_ext(newpage);
100         int i;
101
102         new_ext->order = old_ext->order;
103         new_ext->gfp_mask = old_ext->gfp_mask;
104         new_ext->nr_entries = old_ext->nr_entries;
105
106         for (i = 0; i < ARRAY_SIZE(new_ext->trace_entries); i++)
107                 new_ext->trace_entries[i] = old_ext->trace_entries[i];
108
109         /*
110          * We don't clear the bit on the oldpage as it's going to be freed
111          * after migration. Until then, the info can be useful in case of
112          * a bug, and the overal stats will be off a bit only temporarily.
113          * Also, migrate_misplaced_transhuge_page() can still fail the
114          * migration and then we want the oldpage to retain the info. But
115          * in that case we also don't need to explicitly clear the info from
116          * the new page, which will be freed.
117          */
118         __set_bit(PAGE_EXT_OWNER, &new_ext->flags);
119 }
120
121 static ssize_t
122 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
123                 struct page *page, struct page_ext *page_ext)
124 {
125         int ret;
126         int pageblock_mt, page_mt;
127         char *kbuf;
128         struct stack_trace trace = {
129                 .nr_entries = page_ext->nr_entries,
130                 .entries = &page_ext->trace_entries[0],
131         };
132
133         kbuf = kmalloc(count, GFP_KERNEL);
134         if (!kbuf)
135                 return -ENOMEM;
136
137         ret = snprintf(kbuf, count,
138                         "Page allocated via order %u, mask %#x(%pGg)\n",
139                         page_ext->order, page_ext->gfp_mask,
140                         &page_ext->gfp_mask);
141
142         if (ret >= count)
143                 goto err;
144
145         /* Print information relevant to grouping pages by mobility */
146         pageblock_mt = get_pfnblock_migratetype(page, pfn);
147         page_mt  = gfpflags_to_migratetype(page_ext->gfp_mask);
148         ret += snprintf(kbuf + ret, count - ret,
149                         "PFN %lu type %s Block %lu type %s Flags %#lx(%pGp)\n",
150                         pfn,
151                         migratetype_names[page_mt],
152                         pfn >> pageblock_order,
153                         migratetype_names[pageblock_mt],
154                         page->flags, &page->flags);
155
156         if (ret >= count)
157                 goto err;
158
159         ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
160         if (ret >= count)
161                 goto err;
162
163         if (page_ext->last_migrate_reason != -1) {
164                 ret += snprintf(kbuf + ret, count - ret,
165                         "Page has been migrated, last migrate reason: %s\n",
166                         migrate_reason_names[page_ext->last_migrate_reason]);
167                 if (ret >= count)
168                         goto err;
169         }
170
171         ret += snprintf(kbuf + ret, count - ret, "\n");
172         if (ret >= count)
173                 goto err;
174
175         if (copy_to_user(buf, kbuf, ret))
176                 ret = -EFAULT;
177
178         kfree(kbuf);
179         return ret;
180
181 err:
182         kfree(kbuf);
183         return -ENOMEM;
184 }
185
186 void __dump_page_owner(struct page *page)
187 {
188         struct page_ext *page_ext = lookup_page_ext(page);
189         struct stack_trace trace = {
190                 .nr_entries = page_ext->nr_entries,
191                 .entries = &page_ext->trace_entries[0],
192         };
193         gfp_t gfp_mask = page_ext->gfp_mask;
194         int mt = gfpflags_to_migratetype(gfp_mask);
195
196         if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
197                 pr_alert("page_owner info is not active (free page?)\n");
198                 return;
199         }
200
201         pr_alert("page allocated via order %u, migratetype %s, gfp_mask %#x(%pGg)\n",
202                  page_ext->order, migratetype_names[mt], gfp_mask, &gfp_mask);
203         print_stack_trace(&trace, 0);
204
205         if (page_ext->last_migrate_reason != -1)
206                 pr_alert("page has been migrated, last migrate reason: %s\n",
207                         migrate_reason_names[page_ext->last_migrate_reason]);
208 }
209
210 static ssize_t
211 read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
212 {
213         unsigned long pfn;
214         struct page *page;
215         struct page_ext *page_ext;
216
217         if (!static_branch_unlikely(&page_owner_inited))
218                 return -EINVAL;
219
220         page = NULL;
221         pfn = min_low_pfn + *ppos;
222
223         /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
224         while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
225                 pfn++;
226
227         drain_all_pages(NULL);
228
229         /* Find an allocated page */
230         for (; pfn < max_pfn; pfn++) {
231                 /*
232                  * If the new page is in a new MAX_ORDER_NR_PAGES area,
233                  * validate the area as existing, skip it if not
234                  */
235                 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
236                         pfn += MAX_ORDER_NR_PAGES - 1;
237                         continue;
238                 }
239
240                 /* Check for holes within a MAX_ORDER area */
241                 if (!pfn_valid_within(pfn))
242                         continue;
243
244                 page = pfn_to_page(pfn);
245                 if (PageBuddy(page)) {
246                         unsigned long freepage_order = page_order_unsafe(page);
247
248                         if (freepage_order < MAX_ORDER)
249                                 pfn += (1UL << freepage_order) - 1;
250                         continue;
251                 }
252
253                 page_ext = lookup_page_ext(page);
254
255                 /*
256                  * Some pages could be missed by concurrent allocation or free,
257                  * because we don't hold the zone lock.
258                  */
259                 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
260                         continue;
261
262                 /* Record the next PFN to read in the file offset */
263                 *ppos = (pfn - min_low_pfn) + 1;
264
265                 return print_page_owner(buf, count, pfn, page, page_ext);
266         }
267
268         return 0;
269 }
270
271 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
272 {
273         struct page *page;
274         struct page_ext *page_ext;
275         unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
276         unsigned long end_pfn = pfn + zone->spanned_pages;
277         unsigned long count = 0;
278
279         /* Scan block by block. First and last block may be incomplete */
280         pfn = zone->zone_start_pfn;
281
282         /*
283          * Walk the zone in pageblock_nr_pages steps. If a page block spans
284          * a zone boundary, it will be double counted between zones. This does
285          * not matter as the mixed block count will still be correct
286          */
287         for (; pfn < end_pfn; ) {
288                 if (!pfn_valid(pfn)) {
289                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
290                         continue;
291                 }
292
293                 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
294                 block_end_pfn = min(block_end_pfn, end_pfn);
295
296                 page = pfn_to_page(pfn);
297
298                 for (; pfn < block_end_pfn; pfn++) {
299                         if (!pfn_valid_within(pfn))
300                                 continue;
301
302                         page = pfn_to_page(pfn);
303
304                         /*
305                          * We are safe to check buddy flag and order, because
306                          * this is init stage and only single thread runs.
307                          */
308                         if (PageBuddy(page)) {
309                                 pfn += (1UL << page_order(page)) - 1;
310                                 continue;
311                         }
312
313                         if (PageReserved(page))
314                                 continue;
315
316                         page_ext = lookup_page_ext(page);
317
318                         /* Maybe overraping zone */
319                         if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
320                                 continue;
321
322                         /* Found early allocated page */
323                         set_page_owner(page, 0, 0);
324                         count++;
325                 }
326         }
327
328         pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
329                 pgdat->node_id, zone->name, count);
330 }
331
332 static void init_zones_in_node(pg_data_t *pgdat)
333 {
334         struct zone *zone;
335         struct zone *node_zones = pgdat->node_zones;
336         unsigned long flags;
337
338         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
339                 if (!populated_zone(zone))
340                         continue;
341
342                 spin_lock_irqsave(&zone->lock, flags);
343                 init_pages_in_zone(pgdat, zone);
344                 spin_unlock_irqrestore(&zone->lock, flags);
345         }
346 }
347
348 static void init_early_allocated_pages(void)
349 {
350         pg_data_t *pgdat;
351
352         drain_all_pages(NULL);
353         for_each_online_pgdat(pgdat)
354                 init_zones_in_node(pgdat);
355 }
356
357 static const struct file_operations proc_page_owner_operations = {
358         .read           = read_page_owner,
359 };
360
361 static int __init pageowner_init(void)
362 {
363         struct dentry *dentry;
364
365         if (!static_branch_unlikely(&page_owner_inited)) {
366                 pr_info("page_owner is disabled\n");
367                 return 0;
368         }
369
370         dentry = debugfs_create_file("page_owner", S_IRUSR, NULL,
371                         NULL, &proc_page_owner_operations);
372         if (IS_ERR(dentry))
373                 return PTR_ERR(dentry);
374
375         return 0;
376 }
377 late_initcall(pageowner_init)