Commit | Line | Data |
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48c96a36 JK |
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 int early_page_owner_param(char *buf) | |
14 | { | |
15 | if (!buf) | |
16 | return -EINVAL; | |
17 | ||
18 | if (strcmp(buf, "on") == 0) | |
19 | page_owner_disabled = false; | |
20 | ||
21 | return 0; | |
22 | } | |
23 | early_param("page_owner", early_page_owner_param); | |
24 | ||
25 | static bool need_page_owner(void) | |
26 | { | |
27 | if (page_owner_disabled) | |
28 | return false; | |
29 | ||
30 | return true; | |
31 | } | |
32 | ||
33 | static void init_page_owner(void) | |
34 | { | |
35 | if (page_owner_disabled) | |
36 | return; | |
37 | ||
38 | page_owner_inited = true; | |
39 | } | |
40 | ||
41 | struct page_ext_operations page_owner_ops = { | |
42 | .need = need_page_owner, | |
43 | .init = init_page_owner, | |
44 | }; | |
45 | ||
46 | void __reset_page_owner(struct page *page, unsigned int order) | |
47 | { | |
48 | int i; | |
49 | struct page_ext *page_ext; | |
50 | ||
51 | for (i = 0; i < (1 << order); i++) { | |
52 | page_ext = lookup_page_ext(page + i); | |
53 | __clear_bit(PAGE_EXT_OWNER, &page_ext->flags); | |
54 | } | |
55 | } | |
56 | ||
57 | void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask) | |
58 | { | |
59 | struct page_ext *page_ext; | |
60 | struct stack_trace *trace; | |
61 | ||
62 | page_ext = lookup_page_ext(page); | |
63 | ||
64 | trace = &page_ext->trace; | |
65 | trace->nr_entries = 0; | |
66 | trace->max_entries = ARRAY_SIZE(page_ext->trace_entries); | |
67 | trace->entries = &page_ext->trace_entries[0]; | |
68 | trace->skip = 3; | |
69 | save_stack_trace(&page_ext->trace); | |
70 | ||
71 | page_ext->order = order; | |
72 | page_ext->gfp_mask = gfp_mask; | |
73 | ||
74 | __set_bit(PAGE_EXT_OWNER, &page_ext->flags); | |
75 | } | |
76 | ||
77 | static ssize_t | |
78 | print_page_owner(char __user *buf, size_t count, unsigned long pfn, | |
79 | struct page *page, struct page_ext *page_ext) | |
80 | { | |
81 | int ret; | |
82 | int pageblock_mt, page_mt; | |
83 | char *kbuf; | |
84 | ||
85 | kbuf = kmalloc(count, GFP_KERNEL); | |
86 | if (!kbuf) | |
87 | return -ENOMEM; | |
88 | ||
89 | ret = snprintf(kbuf, count, | |
90 | "Page allocated via order %u, mask 0x%x\n", | |
91 | page_ext->order, page_ext->gfp_mask); | |
92 | ||
93 | if (ret >= count) | |
94 | goto err; | |
95 | ||
96 | /* Print information relevant to grouping pages by mobility */ | |
97 | pageblock_mt = get_pfnblock_migratetype(page, pfn); | |
98 | page_mt = gfpflags_to_migratetype(page_ext->gfp_mask); | |
99 | ret += snprintf(kbuf + ret, count - ret, | |
100 | "PFN %lu Block %lu type %d %s Flags %s%s%s%s%s%s%s%s%s%s%s%s\n", | |
101 | pfn, | |
102 | pfn >> pageblock_order, | |
103 | pageblock_mt, | |
104 | pageblock_mt != page_mt ? "Fallback" : " ", | |
105 | PageLocked(page) ? "K" : " ", | |
106 | PageError(page) ? "E" : " ", | |
107 | PageReferenced(page) ? "R" : " ", | |
108 | PageUptodate(page) ? "U" : " ", | |
109 | PageDirty(page) ? "D" : " ", | |
110 | PageLRU(page) ? "L" : " ", | |
111 | PageActive(page) ? "A" : " ", | |
112 | PageSlab(page) ? "S" : " ", | |
113 | PageWriteback(page) ? "W" : " ", | |
114 | PageCompound(page) ? "C" : " ", | |
115 | PageSwapCache(page) ? "B" : " ", | |
116 | PageMappedToDisk(page) ? "M" : " "); | |
117 | ||
118 | if (ret >= count) | |
119 | goto err; | |
120 | ||
121 | ret += snprint_stack_trace(kbuf + ret, count - ret, | |
122 | &page_ext->trace, 0); | |
123 | if (ret >= count) | |
124 | goto err; | |
125 | ||
126 | ret += snprintf(kbuf + ret, count - ret, "\n"); | |
127 | if (ret >= count) | |
128 | goto err; | |
129 | ||
130 | if (copy_to_user(buf, kbuf, ret)) | |
131 | ret = -EFAULT; | |
132 | ||
133 | kfree(kbuf); | |
134 | return ret; | |
135 | ||
136 | err: | |
137 | kfree(kbuf); | |
138 | return -ENOMEM; | |
139 | } | |
140 | ||
141 | static ssize_t | |
142 | read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) | |
143 | { | |
144 | unsigned long pfn; | |
145 | struct page *page; | |
146 | struct page_ext *page_ext; | |
147 | ||
148 | if (!page_owner_inited) | |
149 | return -EINVAL; | |
150 | ||
151 | page = NULL; | |
152 | pfn = min_low_pfn + *ppos; | |
153 | ||
154 | /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ | |
155 | while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) | |
156 | pfn++; | |
157 | ||
158 | drain_all_pages(NULL); | |
159 | ||
160 | /* Find an allocated page */ | |
161 | for (; pfn < max_pfn; pfn++) { | |
162 | /* | |
163 | * If the new page is in a new MAX_ORDER_NR_PAGES area, | |
164 | * validate the area as existing, skip it if not | |
165 | */ | |
166 | if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) { | |
167 | pfn += MAX_ORDER_NR_PAGES - 1; | |
168 | continue; | |
169 | } | |
170 | ||
171 | /* Check for holes within a MAX_ORDER area */ | |
172 | if (!pfn_valid_within(pfn)) | |
173 | continue; | |
174 | ||
175 | page = pfn_to_page(pfn); | |
176 | if (PageBuddy(page)) { | |
177 | unsigned long freepage_order = page_order_unsafe(page); | |
178 | ||
179 | if (freepage_order < MAX_ORDER) | |
180 | pfn += (1UL << freepage_order) - 1; | |
181 | continue; | |
182 | } | |
183 | ||
184 | page_ext = lookup_page_ext(page); | |
185 | ||
186 | /* | |
187 | * Pages allocated before initialization of page_owner are | |
188 | * non-buddy and have no page_owner info. | |
189 | */ | |
190 | if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) | |
191 | continue; | |
192 | ||
193 | /* Record the next PFN to read in the file offset */ | |
194 | *ppos = (pfn - min_low_pfn) + 1; | |
195 | ||
196 | return print_page_owner(buf, count, pfn, page, page_ext); | |
197 | } | |
198 | ||
199 | return 0; | |
200 | } | |
201 | ||
202 | static const struct file_operations proc_page_owner_operations = { | |
203 | .read = read_page_owner, | |
204 | }; | |
205 | ||
206 | static int __init pageowner_init(void) | |
207 | { | |
208 | struct dentry *dentry; | |
209 | ||
210 | if (!page_owner_inited) { | |
211 | pr_info("page_owner is disabled\n"); | |
212 | return 0; | |
213 | } | |
214 | ||
215 | dentry = debugfs_create_file("page_owner", S_IRUSR, NULL, | |
216 | NULL, &proc_page_owner_operations); | |
217 | if (IS_ERR(dentry)) | |
218 | return PTR_ERR(dentry); | |
219 | ||
220 | return 0; | |
221 | } | |
222 | module_init(pageowner_init) |