| // SPDX-License-Identifier: GPL-2.0 |
| #include <linux/idr.h> |
| #include <linux/slab.h> |
| #include <linux/debugfs.h> |
| #include <linux/seq_file.h> |
| #include <linux/shrinker.h> |
| #include <linux/memcontrol.h> |
| |
| /* defined in vmscan.c */ |
| extern struct rw_semaphore shrinker_rwsem; |
| extern struct list_head shrinker_list; |
| |
| static DEFINE_IDA(shrinker_debugfs_ida); |
| static struct dentry *shrinker_debugfs_root; |
| |
| static unsigned long shrinker_count_objects(struct shrinker *shrinker, |
| struct mem_cgroup *memcg, |
| unsigned long *count_per_node) |
| { |
| unsigned long nr, total = 0; |
| int nid; |
| |
| for_each_node(nid) { |
| if (nid == 0 || (shrinker->flags & SHRINKER_NUMA_AWARE)) { |
| struct shrink_control sc = { |
| .gfp_mask = GFP_KERNEL, |
| .nid = nid, |
| .memcg = memcg, |
| }; |
| |
| nr = shrinker->count_objects(shrinker, &sc); |
| if (nr == SHRINK_EMPTY) |
| nr = 0; |
| } else { |
| nr = 0; |
| } |
| |
| count_per_node[nid] = nr; |
| total += nr; |
| } |
| |
| return total; |
| } |
| |
| static int shrinker_debugfs_count_show(struct seq_file *m, void *v) |
| { |
| struct shrinker *shrinker = m->private; |
| unsigned long *count_per_node; |
| struct mem_cgroup *memcg; |
| unsigned long total; |
| bool memcg_aware; |
| int ret, nid; |
| |
| count_per_node = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL); |
| if (!count_per_node) |
| return -ENOMEM; |
| |
| ret = down_read_killable(&shrinker_rwsem); |
| if (ret) { |
| kfree(count_per_node); |
| return ret; |
| } |
| rcu_read_lock(); |
| |
| memcg_aware = shrinker->flags & SHRINKER_MEMCG_AWARE; |
| |
| memcg = mem_cgroup_iter(NULL, NULL, NULL); |
| do { |
| if (memcg && !mem_cgroup_online(memcg)) |
| continue; |
| |
| total = shrinker_count_objects(shrinker, |
| memcg_aware ? memcg : NULL, |
| count_per_node); |
| if (total) { |
| seq_printf(m, "%lu", mem_cgroup_ino(memcg)); |
| for_each_node(nid) |
| seq_printf(m, " %lu", count_per_node[nid]); |
| seq_putc(m, '\n'); |
| } |
| |
| if (!memcg_aware) { |
| mem_cgroup_iter_break(NULL, memcg); |
| break; |
| } |
| |
| if (signal_pending(current)) { |
| mem_cgroup_iter_break(NULL, memcg); |
| ret = -EINTR; |
| break; |
| } |
| } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL); |
| |
| rcu_read_unlock(); |
| up_read(&shrinker_rwsem); |
| |
| kfree(count_per_node); |
| return ret; |
| } |
| DEFINE_SHOW_ATTRIBUTE(shrinker_debugfs_count); |
| |
| static int shrinker_debugfs_scan_open(struct inode *inode, struct file *file) |
| { |
| file->private_data = inode->i_private; |
| return nonseekable_open(inode, file); |
| } |
| |
| static ssize_t shrinker_debugfs_scan_write(struct file *file, |
| const char __user *buf, |
| size_t size, loff_t *pos) |
| { |
| struct shrinker *shrinker = file->private_data; |
| unsigned long nr_to_scan = 0, ino, read_len; |
| struct shrink_control sc = { |
| .gfp_mask = GFP_KERNEL, |
| }; |
| struct mem_cgroup *memcg = NULL; |
| int nid; |
| char kbuf[72]; |
| ssize_t ret; |
| |
| read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1); |
| if (copy_from_user(kbuf, buf, read_len)) |
| return -EFAULT; |
| kbuf[read_len] = '\0'; |
| |
| if (sscanf(kbuf, "%lu %d %lu", &ino, &nid, &nr_to_scan) != 3) |
| return -EINVAL; |
| |
| if (nid < 0 || nid >= nr_node_ids) |
| return -EINVAL; |
| |
| if (nr_to_scan == 0) |
| return size; |
| |
| if (shrinker->flags & SHRINKER_MEMCG_AWARE) { |
| memcg = mem_cgroup_get_from_ino(ino); |
| if (!memcg || IS_ERR(memcg)) |
| return -ENOENT; |
| |
| if (!mem_cgroup_online(memcg)) { |
| mem_cgroup_put(memcg); |
| return -ENOENT; |
| } |
| } else if (ino != 0) { |
| return -EINVAL; |
| } |
| |
| ret = down_read_killable(&shrinker_rwsem); |
| if (ret) { |
| mem_cgroup_put(memcg); |
| return ret; |
| } |
| |
| sc.nid = nid; |
| sc.memcg = memcg; |
| sc.nr_to_scan = nr_to_scan; |
| sc.nr_scanned = nr_to_scan; |
| |
| shrinker->scan_objects(shrinker, &sc); |
| |
| up_read(&shrinker_rwsem); |
| mem_cgroup_put(memcg); |
| |
| return size; |
| } |
| |
| static const struct file_operations shrinker_debugfs_scan_fops = { |
| .owner = THIS_MODULE, |
| .open = shrinker_debugfs_scan_open, |
| .write = shrinker_debugfs_scan_write, |
| }; |
| |
| int shrinker_debugfs_add(struct shrinker *shrinker) |
| { |
| struct dentry *entry; |
| char buf[128]; |
| int id; |
| |
| lockdep_assert_held(&shrinker_rwsem); |
| |
| /* debugfs isn't initialized yet, add debugfs entries later. */ |
| if (!shrinker_debugfs_root) |
| return 0; |
| |
| id = ida_alloc(&shrinker_debugfs_ida, GFP_KERNEL); |
| if (id < 0) |
| return id; |
| shrinker->debugfs_id = id; |
| |
| snprintf(buf, sizeof(buf), "%s-%d", shrinker->name, id); |
| |
| /* create debugfs entry */ |
| entry = debugfs_create_dir(buf, shrinker_debugfs_root); |
| if (IS_ERR(entry)) { |
| ida_free(&shrinker_debugfs_ida, id); |
| return PTR_ERR(entry); |
| } |
| shrinker->debugfs_entry = entry; |
| |
| debugfs_create_file("count", 0220, entry, shrinker, |
| &shrinker_debugfs_count_fops); |
| debugfs_create_file("scan", 0440, entry, shrinker, |
| &shrinker_debugfs_scan_fops); |
| return 0; |
| } |
| |
| int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) |
| { |
| struct dentry *entry; |
| char buf[128]; |
| const char *new, *old; |
| va_list ap; |
| int ret = 0; |
| |
| va_start(ap, fmt); |
| new = kvasprintf_const(GFP_KERNEL, fmt, ap); |
| va_end(ap); |
| |
| if (!new) |
| return -ENOMEM; |
| |
| down_write(&shrinker_rwsem); |
| |
| old = shrinker->name; |
| shrinker->name = new; |
| |
| if (shrinker->debugfs_entry) { |
| snprintf(buf, sizeof(buf), "%s-%d", shrinker->name, |
| shrinker->debugfs_id); |
| |
| entry = debugfs_rename(shrinker_debugfs_root, |
| shrinker->debugfs_entry, |
| shrinker_debugfs_root, buf); |
| if (IS_ERR(entry)) |
| ret = PTR_ERR(entry); |
| else |
| shrinker->debugfs_entry = entry; |
| } |
| |
| up_write(&shrinker_rwsem); |
| |
| kfree_const(old); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(shrinker_debugfs_rename); |
| |
| void shrinker_debugfs_remove(struct shrinker *shrinker) |
| { |
| lockdep_assert_held(&shrinker_rwsem); |
| |
| kfree_const(shrinker->name); |
| shrinker->name = NULL; |
| |
| if (!shrinker->debugfs_entry) |
| return; |
| |
| debugfs_remove_recursive(shrinker->debugfs_entry); |
| ida_free(&shrinker_debugfs_ida, shrinker->debugfs_id); |
| } |
| |
| static int __init shrinker_debugfs_init(void) |
| { |
| struct shrinker *shrinker; |
| struct dentry *dentry; |
| int ret = 0; |
| |
| dentry = debugfs_create_dir("shrinker", NULL); |
| if (IS_ERR(dentry)) |
| return PTR_ERR(dentry); |
| shrinker_debugfs_root = dentry; |
| |
| /* Create debugfs entries for shrinkers registered at boot */ |
| down_write(&shrinker_rwsem); |
| list_for_each_entry(shrinker, &shrinker_list, list) |
| if (!shrinker->debugfs_entry) { |
| ret = shrinker_debugfs_add(shrinker); |
| if (ret) |
| break; |
| } |
| up_write(&shrinker_rwsem); |
| |
| return ret; |
| } |
| late_initcall(shrinker_debugfs_init); |