1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <linux/idr.h> |
3 | #include <linux/slab.h> |
4 | #include <linux/debugfs.h> |
5 | #include <linux/seq_file.h> |
6 | #include <linux/shrinker.h> |
7 | #include <linux/memcontrol.h> |
8 | |
9 | #include "internal.h" |
10 | |
11 | /* defined in vmscan.c */ |
12 | extern struct mutex shrinker_mutex; |
13 | extern struct list_head shrinker_list; |
14 | |
15 | static DEFINE_IDA(shrinker_debugfs_ida); |
16 | static struct dentry *shrinker_debugfs_root; |
17 | |
18 | static unsigned long shrinker_count_objects(struct shrinker *shrinker, |
19 | struct mem_cgroup *memcg, |
20 | unsigned long *count_per_node) |
21 | { |
22 | unsigned long nr, total = 0; |
23 | int nid; |
24 | |
25 | for_each_node(nid) { |
26 | if (nid == 0 || (shrinker->flags & SHRINKER_NUMA_AWARE)) { |
27 | struct shrink_control sc = { |
28 | .gfp_mask = GFP_KERNEL, |
29 | .nid = nid, |
30 | .memcg = memcg, |
31 | }; |
32 | |
33 | nr = shrinker->count_objects(shrinker, &sc); |
34 | if (nr == SHRINK_EMPTY) |
35 | nr = 0; |
36 | } else { |
37 | nr = 0; |
38 | } |
39 | |
40 | count_per_node[nid] = nr; |
41 | total += nr; |
42 | } |
43 | |
44 | return total; |
45 | } |
46 | |
47 | static int shrinker_debugfs_count_show(struct seq_file *m, void *v) |
48 | { |
49 | struct shrinker *shrinker = m->private; |
50 | unsigned long *count_per_node; |
51 | struct mem_cgroup *memcg; |
52 | unsigned long total; |
53 | bool memcg_aware; |
54 | int ret = 0, nid; |
55 | |
56 | count_per_node = kcalloc(n: nr_node_ids, size: sizeof(unsigned long), GFP_KERNEL); |
57 | if (!count_per_node) |
58 | return -ENOMEM; |
59 | |
60 | rcu_read_lock(); |
61 | |
62 | memcg_aware = shrinker->flags & SHRINKER_MEMCG_AWARE; |
63 | |
64 | memcg = mem_cgroup_iter(NULL, NULL, NULL); |
65 | do { |
66 | if (memcg && !mem_cgroup_online(memcg)) |
67 | continue; |
68 | |
69 | total = shrinker_count_objects(shrinker, |
70 | memcg: memcg_aware ? memcg : NULL, |
71 | count_per_node); |
72 | if (total) { |
73 | seq_printf(m, fmt: "%lu" , mem_cgroup_ino(memcg)); |
74 | for_each_node(nid) |
75 | seq_printf(m, fmt: " %lu" , count_per_node[nid]); |
76 | seq_putc(m, c: '\n'); |
77 | } |
78 | |
79 | if (!memcg_aware) { |
80 | mem_cgroup_iter_break(NULL, memcg); |
81 | break; |
82 | } |
83 | |
84 | if (signal_pending(current)) { |
85 | mem_cgroup_iter_break(NULL, memcg); |
86 | ret = -EINTR; |
87 | break; |
88 | } |
89 | } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL); |
90 | |
91 | rcu_read_unlock(); |
92 | |
93 | kfree(objp: count_per_node); |
94 | return ret; |
95 | } |
96 | DEFINE_SHOW_ATTRIBUTE(shrinker_debugfs_count); |
97 | |
98 | static int shrinker_debugfs_scan_open(struct inode *inode, struct file *file) |
99 | { |
100 | file->private_data = inode->i_private; |
101 | return nonseekable_open(inode, filp: file); |
102 | } |
103 | |
104 | static ssize_t shrinker_debugfs_scan_write(struct file *file, |
105 | const char __user *buf, |
106 | size_t size, loff_t *pos) |
107 | { |
108 | struct shrinker *shrinker = file->private_data; |
109 | unsigned long nr_to_scan = 0, ino, read_len; |
110 | struct shrink_control sc = { |
111 | .gfp_mask = GFP_KERNEL, |
112 | }; |
113 | struct mem_cgroup *memcg = NULL; |
114 | int nid; |
115 | char kbuf[72]; |
116 | |
117 | read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1); |
118 | if (copy_from_user(to: kbuf, from: buf, n: read_len)) |
119 | return -EFAULT; |
120 | kbuf[read_len] = '\0'; |
121 | |
122 | if (sscanf(kbuf, "%lu %d %lu" , &ino, &nid, &nr_to_scan) != 3) |
123 | return -EINVAL; |
124 | |
125 | if (nid < 0 || nid >= nr_node_ids) |
126 | return -EINVAL; |
127 | |
128 | if (nr_to_scan == 0) |
129 | return size; |
130 | |
131 | if (shrinker->flags & SHRINKER_MEMCG_AWARE) { |
132 | memcg = mem_cgroup_get_from_ino(ino); |
133 | if (!memcg || IS_ERR(ptr: memcg)) |
134 | return -ENOENT; |
135 | |
136 | if (!mem_cgroup_online(memcg)) { |
137 | mem_cgroup_put(memcg); |
138 | return -ENOENT; |
139 | } |
140 | } else if (ino != 0) { |
141 | return -EINVAL; |
142 | } |
143 | |
144 | sc.nid = nid; |
145 | sc.memcg = memcg; |
146 | sc.nr_to_scan = nr_to_scan; |
147 | sc.nr_scanned = nr_to_scan; |
148 | |
149 | shrinker->scan_objects(shrinker, &sc); |
150 | |
151 | mem_cgroup_put(memcg); |
152 | |
153 | return size; |
154 | } |
155 | |
156 | static const struct file_operations shrinker_debugfs_scan_fops = { |
157 | .owner = THIS_MODULE, |
158 | .open = shrinker_debugfs_scan_open, |
159 | .write = shrinker_debugfs_scan_write, |
160 | }; |
161 | |
162 | int shrinker_debugfs_add(struct shrinker *shrinker) |
163 | { |
164 | struct dentry *entry; |
165 | char buf[128]; |
166 | int id; |
167 | |
168 | lockdep_assert_held(&shrinker_mutex); |
169 | |
170 | /* debugfs isn't initialized yet, add debugfs entries later. */ |
171 | if (!shrinker_debugfs_root) |
172 | return 0; |
173 | |
174 | id = ida_alloc(ida: &shrinker_debugfs_ida, GFP_KERNEL); |
175 | if (id < 0) |
176 | return id; |
177 | shrinker->debugfs_id = id; |
178 | |
179 | snprintf(buf, size: sizeof(buf), fmt: "%s-%d" , shrinker->name, id); |
180 | |
181 | /* create debugfs entry */ |
182 | entry = debugfs_create_dir(name: buf, parent: shrinker_debugfs_root); |
183 | if (IS_ERR(ptr: entry)) { |
184 | ida_free(&shrinker_debugfs_ida, id); |
185 | return PTR_ERR(ptr: entry); |
186 | } |
187 | shrinker->debugfs_entry = entry; |
188 | |
189 | debugfs_create_file(name: "count" , mode: 0440, parent: entry, data: shrinker, |
190 | fops: &shrinker_debugfs_count_fops); |
191 | debugfs_create_file(name: "scan" , mode: 0220, parent: entry, data: shrinker, |
192 | fops: &shrinker_debugfs_scan_fops); |
193 | return 0; |
194 | } |
195 | |
196 | int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) |
197 | { |
198 | struct dentry *entry; |
199 | char buf[128]; |
200 | const char *new, *old; |
201 | va_list ap; |
202 | int ret = 0; |
203 | |
204 | va_start(ap, fmt); |
205 | new = kvasprintf_const(GFP_KERNEL, fmt, args: ap); |
206 | va_end(ap); |
207 | |
208 | if (!new) |
209 | return -ENOMEM; |
210 | |
211 | mutex_lock(&shrinker_mutex); |
212 | |
213 | old = shrinker->name; |
214 | shrinker->name = new; |
215 | |
216 | if (shrinker->debugfs_entry) { |
217 | snprintf(buf, size: sizeof(buf), fmt: "%s-%d" , shrinker->name, |
218 | shrinker->debugfs_id); |
219 | |
220 | entry = debugfs_rename(old_dir: shrinker_debugfs_root, |
221 | old_dentry: shrinker->debugfs_entry, |
222 | new_dir: shrinker_debugfs_root, new_name: buf); |
223 | if (IS_ERR(ptr: entry)) |
224 | ret = PTR_ERR(ptr: entry); |
225 | else |
226 | shrinker->debugfs_entry = entry; |
227 | } |
228 | |
229 | mutex_unlock(lock: &shrinker_mutex); |
230 | |
231 | kfree_const(x: old); |
232 | |
233 | return ret; |
234 | } |
235 | EXPORT_SYMBOL(shrinker_debugfs_rename); |
236 | |
237 | struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker, |
238 | int *debugfs_id) |
239 | { |
240 | struct dentry *entry = shrinker->debugfs_entry; |
241 | |
242 | lockdep_assert_held(&shrinker_mutex); |
243 | |
244 | *debugfs_id = entry ? shrinker->debugfs_id : -1; |
245 | shrinker->debugfs_entry = NULL; |
246 | |
247 | return entry; |
248 | } |
249 | |
250 | void shrinker_debugfs_remove(struct dentry *debugfs_entry, int debugfs_id) |
251 | { |
252 | debugfs_remove_recursive(dentry: debugfs_entry); |
253 | ida_free(&shrinker_debugfs_ida, id: debugfs_id); |
254 | } |
255 | |
256 | static int __init shrinker_debugfs_init(void) |
257 | { |
258 | struct shrinker *shrinker; |
259 | struct dentry *dentry; |
260 | int ret = 0; |
261 | |
262 | dentry = debugfs_create_dir(name: "shrinker" , NULL); |
263 | if (IS_ERR(ptr: dentry)) |
264 | return PTR_ERR(ptr: dentry); |
265 | shrinker_debugfs_root = dentry; |
266 | |
267 | /* Create debugfs entries for shrinkers registered at boot */ |
268 | mutex_lock(&shrinker_mutex); |
269 | list_for_each_entry(shrinker, &shrinker_list, list) |
270 | if (!shrinker->debugfs_entry) { |
271 | ret = shrinker_debugfs_add(shrinker); |
272 | if (ret) |
273 | break; |
274 | } |
275 | mutex_unlock(lock: &shrinker_mutex); |
276 | |
277 | return ret; |
278 | } |
279 | late_initcall(shrinker_debugfs_init); |
280 | |