Merge remote-tracking branch 'asoc/fix/intel' into asoc-linus
[firefly-linux-kernel-4.4.55.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 "internal.h"
9
10 static bool page_owner_disabled = true;
11 bool page_owner_inited __read_mostly;
12
13 static void init_early_allocated_pages(void);
14
15 static int early_page_owner_param(char *buf)
16 {
17         if (!buf)
18                 return -EINVAL;
19
20         if (strcmp(buf, "on") == 0)
21                 page_owner_disabled = false;
22
23         return 0;
24 }
25 early_param("page_owner", early_page_owner_param);
26
27 static bool need_page_owner(void)
28 {
29         if (page_owner_disabled)
30                 return false;
31
32         return true;
33 }
34
35 static void init_page_owner(void)
36 {
37         if (page_owner_disabled)
38                 return;
39
40         page_owner_inited = true;
41         init_early_allocated_pages();
42 }
43
44 struct page_ext_operations page_owner_ops = {
45         .need = need_page_owner,
46         .init = init_page_owner,
47 };
48
49 void __reset_page_owner(struct page *page, unsigned int order)
50 {
51         int i;
52         struct page_ext *page_ext;
53
54         for (i = 0; i < (1 << order); i++) {
55                 page_ext = lookup_page_ext(page + i);
56                 __clear_bit(PAGE_EXT_OWNER, &page_ext->flags);
57         }
58 }
59
60 void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask)
61 {
62         struct page_ext *page_ext = lookup_page_ext(page);
63         struct stack_trace trace = {
64                 .nr_entries = 0,
65                 .max_entries = ARRAY_SIZE(page_ext->trace_entries),
66                 .entries = &page_ext->trace_entries[0],
67                 .skip = 3,
68         };
69
70         save_stack_trace(&trace);
71
72         page_ext->order = order;
73         page_ext->gfp_mask = gfp_mask;
74         page_ext->nr_entries = trace.nr_entries;
75
76         __set_bit(PAGE_EXT_OWNER, &page_ext->flags);
77 }
78
79 static ssize_t
80 print_page_owner(char __user *buf, size_t count, unsigned long pfn,
81                 struct page *page, struct page_ext *page_ext)
82 {
83         int ret;
84         int pageblock_mt, page_mt;
85         char *kbuf;
86         struct stack_trace trace = {
87                 .nr_entries = page_ext->nr_entries,
88                 .entries = &page_ext->trace_entries[0],
89         };
90
91         kbuf = kmalloc(count, GFP_KERNEL);
92         if (!kbuf)
93                 return -ENOMEM;
94
95         ret = snprintf(kbuf, count,
96                         "Page allocated via order %u, mask 0x%x\n",
97                         page_ext->order, page_ext->gfp_mask);
98
99         if (ret >= count)
100                 goto err;
101
102         /* Print information relevant to grouping pages by mobility */
103         pageblock_mt = get_pfnblock_migratetype(page, pfn);
104         page_mt  = gfpflags_to_migratetype(page_ext->gfp_mask);
105         ret += snprintf(kbuf + ret, count - ret,
106                         "PFN %lu Block %lu type %d %s Flags %s%s%s%s%s%s%s%s%s%s%s%s\n",
107                         pfn,
108                         pfn >> pageblock_order,
109                         pageblock_mt,
110                         pageblock_mt != page_mt ? "Fallback" : "        ",
111                         PageLocked(page)        ? "K" : " ",
112                         PageError(page)         ? "E" : " ",
113                         PageReferenced(page)    ? "R" : " ",
114                         PageUptodate(page)      ? "U" : " ",
115                         PageDirty(page)         ? "D" : " ",
116                         PageLRU(page)           ? "L" : " ",
117                         PageActive(page)        ? "A" : " ",
118                         PageSlab(page)          ? "S" : " ",
119                         PageWriteback(page)     ? "W" : " ",
120                         PageCompound(page)      ? "C" : " ",
121                         PageSwapCache(page)     ? "B" : " ",
122                         PageMappedToDisk(page)  ? "M" : " ");
123
124         if (ret >= count)
125                 goto err;
126
127         ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
128         if (ret >= count)
129                 goto err;
130
131         ret += snprintf(kbuf + ret, count - ret, "\n");
132         if (ret >= count)
133                 goto err;
134
135         if (copy_to_user(buf, kbuf, ret))
136                 ret = -EFAULT;
137
138         kfree(kbuf);
139         return ret;
140
141 err:
142         kfree(kbuf);
143         return -ENOMEM;
144 }
145
146 static ssize_t
147 read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
148 {
149         unsigned long pfn;
150         struct page *page;
151         struct page_ext *page_ext;
152
153         if (!page_owner_inited)
154                 return -EINVAL;
155
156         page = NULL;
157         pfn = min_low_pfn + *ppos;
158
159         /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
160         while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
161                 pfn++;
162
163         drain_all_pages(NULL);
164
165         /* Find an allocated page */
166         for (; pfn < max_pfn; pfn++) {
167                 /*
168                  * If the new page is in a new MAX_ORDER_NR_PAGES area,
169                  * validate the area as existing, skip it if not
170                  */
171                 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
172                         pfn += MAX_ORDER_NR_PAGES - 1;
173                         continue;
174                 }
175
176                 /* Check for holes within a MAX_ORDER area */
177                 if (!pfn_valid_within(pfn))
178                         continue;
179
180                 page = pfn_to_page(pfn);
181                 if (PageBuddy(page)) {
182                         unsigned long freepage_order = page_order_unsafe(page);
183
184                         if (freepage_order < MAX_ORDER)
185                                 pfn += (1UL << freepage_order) - 1;
186                         continue;
187                 }
188
189                 page_ext = lookup_page_ext(page);
190
191                 /*
192                  * Some pages could be missed by concurrent allocation or free,
193                  * because we don't hold the zone lock.
194                  */
195                 if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
196                         continue;
197
198                 /* Record the next PFN to read in the file offset */
199                 *ppos = (pfn - min_low_pfn) + 1;
200
201                 return print_page_owner(buf, count, pfn, page, page_ext);
202         }
203
204         return 0;
205 }
206
207 static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
208 {
209         struct page *page;
210         struct page_ext *page_ext;
211         unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
212         unsigned long end_pfn = pfn + zone->spanned_pages;
213         unsigned long count = 0;
214
215         /* Scan block by block. First and last block may be incomplete */
216         pfn = zone->zone_start_pfn;
217
218         /*
219          * Walk the zone in pageblock_nr_pages steps. If a page block spans
220          * a zone boundary, it will be double counted between zones. This does
221          * not matter as the mixed block count will still be correct
222          */
223         for (; pfn < end_pfn; ) {
224                 if (!pfn_valid(pfn)) {
225                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
226                         continue;
227                 }
228
229                 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
230                 block_end_pfn = min(block_end_pfn, end_pfn);
231
232                 page = pfn_to_page(pfn);
233
234                 for (; pfn < block_end_pfn; pfn++) {
235                         if (!pfn_valid_within(pfn))
236                                 continue;
237
238                         page = pfn_to_page(pfn);
239
240                         /*
241                          * We are safe to check buddy flag and order, because
242                          * this is init stage and only single thread runs.
243                          */
244                         if (PageBuddy(page)) {
245                                 pfn += (1UL << page_order(page)) - 1;
246                                 continue;
247                         }
248
249                         if (PageReserved(page))
250                                 continue;
251
252                         page_ext = lookup_page_ext(page);
253
254                         /* Maybe overraping zone */
255                         if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
256                                 continue;
257
258                         /* Found early allocated page */
259                         set_page_owner(page, 0, 0);
260                         count++;
261                 }
262         }
263
264         pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
265                 pgdat->node_id, zone->name, count);
266 }
267
268 static void init_zones_in_node(pg_data_t *pgdat)
269 {
270         struct zone *zone;
271         struct zone *node_zones = pgdat->node_zones;
272         unsigned long flags;
273
274         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
275                 if (!populated_zone(zone))
276                         continue;
277
278                 spin_lock_irqsave(&zone->lock, flags);
279                 init_pages_in_zone(pgdat, zone);
280                 spin_unlock_irqrestore(&zone->lock, flags);
281         }
282 }
283
284 static void init_early_allocated_pages(void)
285 {
286         pg_data_t *pgdat;
287
288         drain_all_pages(NULL);
289         for_each_online_pgdat(pgdat)
290                 init_zones_in_node(pgdat);
291 }
292
293 static const struct file_operations proc_page_owner_operations = {
294         .read           = read_page_owner,
295 };
296
297 static int __init pageowner_init(void)
298 {
299         struct dentry *dentry;
300
301         if (!page_owner_inited) {
302                 pr_info("page_owner is disabled\n");
303                 return 0;
304         }
305
306         dentry = debugfs_create_file("page_owner", S_IRUSR, NULL,
307                         NULL, &proc_page_owner_operations);
308         if (IS_ERR(dentry))
309                 return PTR_ERR(dentry);
310
311         return 0;
312 }
313 module_init(pageowner_init)