Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 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> |
Qi Zheng | 20cd189 | 2023-03-13 19:28:16 +0800 | [diff] [blame] | 8 | #include <linux/srcu.h> |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 9 | |
| 10 | /* defined in vmscan.c */ |
Qi Zheng | cf2e309 | 2023-03-13 19:28:19 +0800 | [diff] [blame] | 11 | extern struct mutex shrinker_mutex; |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 12 | extern struct list_head shrinker_list; |
Qi Zheng | 20cd189 | 2023-03-13 19:28:16 +0800 | [diff] [blame] | 13 | extern struct srcu_struct shrinker_srcu; |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 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; |
Qi Zheng | 20cd189 | 2023-03-13 19:28:16 +0800 | [diff] [blame] | 54 | int ret = 0, nid, srcu_idx; |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 55 | |
| 56 | count_per_node = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL); |
| 57 | if (!count_per_node) |
| 58 | return -ENOMEM; |
| 59 | |
Qi Zheng | 20cd189 | 2023-03-13 19:28:16 +0800 | [diff] [blame] | 60 | srcu_idx = srcu_read_lock(&shrinker_srcu); |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 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_aware ? memcg : NULL, |
| 71 | count_per_node); |
| 72 | if (total) { |
| 73 | seq_printf(m, "%lu", mem_cgroup_ino(memcg)); |
| 74 | for_each_node(nid) |
| 75 | seq_printf(m, " %lu", count_per_node[nid]); |
| 76 | seq_putc(m, '\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 | |
Qi Zheng | 20cd189 | 2023-03-13 19:28:16 +0800 | [diff] [blame] | 91 | srcu_read_unlock(&shrinker_srcu, srcu_idx); |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 92 | |
| 93 | kfree(count_per_node); |
| 94 | return ret; |
| 95 | } |
| 96 | DEFINE_SHOW_ATTRIBUTE(shrinker_debugfs_count); |
| 97 | |
Roman Gushchin | bbf535f | 2022-05-31 20:22:27 -0700 | [diff] [blame] | 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, 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; |
Qi Zheng | 20cd189 | 2023-03-13 19:28:16 +0800 | [diff] [blame] | 114 | int nid, srcu_idx; |
Roman Gushchin | bbf535f | 2022-05-31 20:22:27 -0700 | [diff] [blame] | 115 | char kbuf[72]; |
Roman Gushchin | bbf535f | 2022-05-31 20:22:27 -0700 | [diff] [blame] | 116 | |
| 117 | read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1); |
| 118 | if (copy_from_user(kbuf, buf, 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(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 | |
Qi Zheng | 20cd189 | 2023-03-13 19:28:16 +0800 | [diff] [blame] | 144 | srcu_idx = srcu_read_lock(&shrinker_srcu); |
Roman Gushchin | bbf535f | 2022-05-31 20:22:27 -0700 | [diff] [blame] | 145 | |
| 146 | sc.nid = nid; |
| 147 | sc.memcg = memcg; |
| 148 | sc.nr_to_scan = nr_to_scan; |
| 149 | sc.nr_scanned = nr_to_scan; |
| 150 | |
| 151 | shrinker->scan_objects(shrinker, &sc); |
| 152 | |
Qi Zheng | 20cd189 | 2023-03-13 19:28:16 +0800 | [diff] [blame] | 153 | srcu_read_unlock(&shrinker_srcu, srcu_idx); |
Roman Gushchin | bbf535f | 2022-05-31 20:22:27 -0700 | [diff] [blame] | 154 | mem_cgroup_put(memcg); |
| 155 | |
| 156 | return size; |
| 157 | } |
| 158 | |
| 159 | static const struct file_operations shrinker_debugfs_scan_fops = { |
| 160 | .owner = THIS_MODULE, |
| 161 | .open = shrinker_debugfs_scan_open, |
| 162 | .write = shrinker_debugfs_scan_write, |
| 163 | }; |
| 164 | |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 165 | int shrinker_debugfs_add(struct shrinker *shrinker) |
| 166 | { |
| 167 | struct dentry *entry; |
Roman Gushchin | e33c267 | 2022-05-31 20:22:24 -0700 | [diff] [blame] | 168 | char buf[128]; |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 169 | int id; |
| 170 | |
Qi Zheng | cf2e309 | 2023-03-13 19:28:19 +0800 | [diff] [blame] | 171 | lockdep_assert_held(&shrinker_mutex); |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 172 | |
| 173 | /* debugfs isn't initialized yet, add debugfs entries later. */ |
| 174 | if (!shrinker_debugfs_root) |
| 175 | return 0; |
| 176 | |
| 177 | id = ida_alloc(&shrinker_debugfs_ida, GFP_KERNEL); |
| 178 | if (id < 0) |
| 179 | return id; |
| 180 | shrinker->debugfs_id = id; |
| 181 | |
Roman Gushchin | e33c267 | 2022-05-31 20:22:24 -0700 | [diff] [blame] | 182 | snprintf(buf, sizeof(buf), "%s-%d", shrinker->name, id); |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 183 | |
| 184 | /* create debugfs entry */ |
| 185 | entry = debugfs_create_dir(buf, shrinker_debugfs_root); |
| 186 | if (IS_ERR(entry)) { |
| 187 | ida_free(&shrinker_debugfs_ida, id); |
| 188 | return PTR_ERR(entry); |
| 189 | } |
| 190 | shrinker->debugfs_entry = entry; |
| 191 | |
John Keeping | 2124f79 | 2023-04-18 11:19:05 +0100 | [diff] [blame] | 192 | debugfs_create_file("count", 0440, entry, shrinker, |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 193 | &shrinker_debugfs_count_fops); |
John Keeping | 2124f79 | 2023-04-18 11:19:05 +0100 | [diff] [blame] | 194 | debugfs_create_file("scan", 0220, entry, shrinker, |
Roman Gushchin | bbf535f | 2022-05-31 20:22:27 -0700 | [diff] [blame] | 195 | &shrinker_debugfs_scan_fops); |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 196 | return 0; |
| 197 | } |
| 198 | |
Roman Gushchin | e33c267 | 2022-05-31 20:22:24 -0700 | [diff] [blame] | 199 | int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) |
| 200 | { |
| 201 | struct dentry *entry; |
| 202 | char buf[128]; |
| 203 | const char *new, *old; |
| 204 | va_list ap; |
| 205 | int ret = 0; |
| 206 | |
| 207 | va_start(ap, fmt); |
| 208 | new = kvasprintf_const(GFP_KERNEL, fmt, ap); |
| 209 | va_end(ap); |
| 210 | |
| 211 | if (!new) |
| 212 | return -ENOMEM; |
| 213 | |
Qi Zheng | cf2e309 | 2023-03-13 19:28:19 +0800 | [diff] [blame] | 214 | mutex_lock(&shrinker_mutex); |
Roman Gushchin | e33c267 | 2022-05-31 20:22:24 -0700 | [diff] [blame] | 215 | |
| 216 | old = shrinker->name; |
| 217 | shrinker->name = new; |
| 218 | |
| 219 | if (shrinker->debugfs_entry) { |
| 220 | snprintf(buf, sizeof(buf), "%s-%d", shrinker->name, |
| 221 | shrinker->debugfs_id); |
| 222 | |
| 223 | entry = debugfs_rename(shrinker_debugfs_root, |
| 224 | shrinker->debugfs_entry, |
| 225 | shrinker_debugfs_root, buf); |
| 226 | if (IS_ERR(entry)) |
| 227 | ret = PTR_ERR(entry); |
| 228 | else |
| 229 | shrinker->debugfs_entry = entry; |
| 230 | } |
| 231 | |
Qi Zheng | cf2e309 | 2023-03-13 19:28:19 +0800 | [diff] [blame] | 232 | mutex_unlock(&shrinker_mutex); |
Roman Gushchin | e33c267 | 2022-05-31 20:22:24 -0700 | [diff] [blame] | 233 | |
| 234 | kfree_const(old); |
| 235 | |
| 236 | return ret; |
| 237 | } |
| 238 | EXPORT_SYMBOL(shrinker_debugfs_rename); |
| 239 | |
Qi Zheng | badc28d | 2023-02-02 18:56:12 +0800 | [diff] [blame] | 240 | struct dentry *shrinker_debugfs_remove(struct shrinker *shrinker) |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 241 | { |
Qi Zheng | badc28d | 2023-02-02 18:56:12 +0800 | [diff] [blame] | 242 | struct dentry *entry = shrinker->debugfs_entry; |
| 243 | |
Qi Zheng | cf2e309 | 2023-03-13 19:28:19 +0800 | [diff] [blame] | 244 | lockdep_assert_held(&shrinker_mutex); |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 245 | |
Roman Gushchin | e33c267 | 2022-05-31 20:22:24 -0700 | [diff] [blame] | 246 | kfree_const(shrinker->name); |
Tetsuo Handa | 14773bf | 2022-07-20 23:47:55 +0900 | [diff] [blame] | 247 | shrinker->name = NULL; |
Roman Gushchin | e33c267 | 2022-05-31 20:22:24 -0700 | [diff] [blame] | 248 | |
Qi Zheng | badc28d | 2023-02-02 18:56:12 +0800 | [diff] [blame] | 249 | if (entry) { |
| 250 | ida_free(&shrinker_debugfs_ida, shrinker->debugfs_id); |
| 251 | shrinker->debugfs_entry = NULL; |
| 252 | } |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 253 | |
Qi Zheng | badc28d | 2023-02-02 18:56:12 +0800 | [diff] [blame] | 254 | return entry; |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 255 | } |
| 256 | |
| 257 | static int __init shrinker_debugfs_init(void) |
| 258 | { |
| 259 | struct shrinker *shrinker; |
| 260 | struct dentry *dentry; |
| 261 | int ret = 0; |
| 262 | |
| 263 | dentry = debugfs_create_dir("shrinker", NULL); |
| 264 | if (IS_ERR(dentry)) |
| 265 | return PTR_ERR(dentry); |
| 266 | shrinker_debugfs_root = dentry; |
| 267 | |
| 268 | /* Create debugfs entries for shrinkers registered at boot */ |
Qi Zheng | cf2e309 | 2023-03-13 19:28:19 +0800 | [diff] [blame] | 269 | mutex_lock(&shrinker_mutex); |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 270 | list_for_each_entry(shrinker, &shrinker_list, list) |
| 271 | if (!shrinker->debugfs_entry) { |
| 272 | ret = shrinker_debugfs_add(shrinker); |
| 273 | if (ret) |
| 274 | break; |
| 275 | } |
Qi Zheng | cf2e309 | 2023-03-13 19:28:19 +0800 | [diff] [blame] | 276 | mutex_unlock(&shrinker_mutex); |
Roman Gushchin | 5035ebc | 2022-05-31 20:22:23 -0700 | [diff] [blame] | 277 | |
| 278 | return ret; |
| 279 | } |
| 280 | late_initcall(shrinker_debugfs_init); |