[linux-block.git] / mm / shrinker_debug.c

// 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);
Commit	Line	Data
5035ebc6 RG	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	/* defined in vmscan.c */
	10	extern struct rw_semaphore shrinker_rwsem;
	11	extern struct list_head shrinker_list;
	12
	13	static DEFINE_IDA(shrinker_debugfs_ida);
	14	static struct dentry *shrinker_debugfs_root;
	15
	16	static unsigned long shrinker_count_objects(struct shrinker *shrinker,
	17	struct mem_cgroup *memcg,
	18	unsigned long *count_per_node)
	19	{
	20	unsigned long nr, total = 0;
	21	int nid;
	22
	23	for_each_node(nid) {
	24	if (nid == 0 \|\| (shrinker->flags & SHRINKER_NUMA_AWARE)) {
	25	struct shrink_control sc = {
	26	.gfp_mask = GFP_KERNEL,
	27	.nid = nid,
	28	.memcg = memcg,
	29	};
	30
	31	nr = shrinker->count_objects(shrinker, &sc);
	32	if (nr == SHRINK_EMPTY)
	33	nr = 0;
	34	} else {
	35	nr = 0;
	36	}
	37
	38	count_per_node[nid] = nr;
	39	total += nr;
	40	}
	41
	42	return total;
	43	}
	44
	45	static int shrinker_debugfs_count_show(struct seq_file m, void v)
	46	{
	47	struct shrinker *shrinker = m->private;
	48	unsigned long *count_per_node;
	49	struct mem_cgroup *memcg;
	50	unsigned long total;
	51	bool memcg_aware;
	52	int ret, nid;
	53
	54	count_per_node = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
	55	if (!count_per_node)
	56	return -ENOMEM;
	57
	58	ret = down_read_killable(&shrinker_rwsem);
	59	if (ret) {
	60	kfree(count_per_node);
	61	return ret;
	62	}
	63	rcu_read_lock();
	64
65	memcg_aware = shrinker->flags & SHRINKER_MEMCG_AWARE;
66
67	memcg = mem_cgroup_iter(NULL, NULL, NULL);
68	do {
69	if (memcg && !mem_cgroup_online(memcg))
70	continue;
71
72	total = shrinker_count_objects(shrinker,
73	memcg_aware ? memcg : NULL,
74	count_per_node);
75	if (total) {
76	seq_printf(m, "%lu", mem_cgroup_ino(memcg));
77	for_each_node(nid)
78	seq_printf(m, " %lu", count_per_node[nid]);
79	seq_putc(m, '\n');
80	}
81
82	if (!memcg_aware) {
83	mem_cgroup_iter_break(NULL, memcg);
84	break;
85	}
86
87	if (signal_pending(current)) {
88	mem_cgroup_iter_break(NULL, memcg);
89	ret = -EINTR;
90	break;
91	}
92	} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
93
94	rcu_read_unlock();
95	up_read(&shrinker_rwsem);
96
97	kfree(count_per_node);
98	return ret;
99	}
100	DEFINE_SHOW_ATTRIBUTE(shrinker_debugfs_count);
101
bbf535fd RG	102	static int shrinker_debugfs_scan_open(struct inode inode, struct file file)
	103	{
	104	file->private_data = inode->i_private;
	105	return nonseekable_open(inode, file);
	106	}
	107
	108	static ssize_t shrinker_debugfs_scan_write(struct file *file,
	109	const char __user *buf,
	110	size_t size, loff_t *pos)
	111	{
	112	struct shrinker *shrinker = file->private_data;
	113	unsigned long nr_to_scan = 0, ino, read_len;
	114	struct shrink_control sc = {
	115	.gfp_mask = GFP_KERNEL,
	116	};
	117	struct mem_cgroup *memcg = NULL;
	118	int nid;
	119	char kbuf[72];
	120	ssize_t ret;
	121
	122	read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1);
	123	if (copy_from_user(kbuf, buf, read_len))
	124	return -EFAULT;
	125	kbuf[read_len] = '\0';
	126
	127	if (sscanf(kbuf, "%lu %d %lu", &ino, &nid, &nr_to_scan) != 3)
	128	return -EINVAL;
	129
	130	if (nid < 0 \|\| nid >= nr_node_ids)
	131	return -EINVAL;
	132
	133	if (nr_to_scan == 0)
	134	return size;
	135
	136	if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
	137	memcg = mem_cgroup_get_from_ino(ino);
	138	if (!memcg \|\| IS_ERR(memcg))
	139	return -ENOENT;
	140
	141	if (!mem_cgroup_online(memcg)) {
	142	mem_cgroup_put(memcg);
	143	return -ENOENT;
	144	}
	145	} else if (ino != 0) {
	146	return -EINVAL;
	147	}
	148
	149	ret = down_read_killable(&shrinker_rwsem);
	150	if (ret) {
	151	mem_cgroup_put(memcg);
	152	return ret;
	153	}
	154
	155	sc.nid = nid;
	156	sc.memcg = memcg;
	157	sc.nr_to_scan = nr_to_scan;
	158	sc.nr_scanned = nr_to_scan;
	159
	160	shrinker->scan_objects(shrinker, &sc);
	161
	162	up_read(&shrinker_rwsem);
	163	mem_cgroup_put(memcg);
	164
	165	return size;
166	}
167
168	static const struct file_operations shrinker_debugfs_scan_fops = {
169	.owner = THIS_MODULE,
170	.open = shrinker_debugfs_scan_open,
171	.write = shrinker_debugfs_scan_write,
172	};
173
5035ebc6 RG	174	int shrinker_debugfs_add(struct shrinker *shrinker)
	175	{
	176	struct dentry *entry;
e33c267a	177	char buf[128];
5035ebc6 RG	178	int id;
	179
	180	lockdep_assert_held(&shrinker_rwsem);
	181
	182	/* debugfs isn't initialized yet, add debugfs entries later. */
	183	if (!shrinker_debugfs_root)
	184	return 0;
	185
	186	id = ida_alloc(&shrinker_debugfs_ida, GFP_KERNEL);
	187	if (id < 0)
	188	return id;
	189	shrinker->debugfs_id = id;
	190
e33c267a	191	snprintf(buf, sizeof(buf), "%s-%d", shrinker->name, id);
5035ebc6 RG	192
	193	/* create debugfs entry */
	194	entry = debugfs_create_dir(buf, shrinker_debugfs_root);
	195	if (IS_ERR(entry)) {
	196	ida_free(&shrinker_debugfs_ida, id);
	197	return PTR_ERR(entry);
	198	}
	199	shrinker->debugfs_entry = entry;
	200
	201	debugfs_create_file("count", 0220, entry, shrinker,
	202	&shrinker_debugfs_count_fops);
bbf535fd RG	203	debugfs_create_file("scan", 0440, entry, shrinker,
bbf535fd RG	204	&shrinker_debugfs_scan_fops);
5035ebc6 RG	205	return 0;
	206	}
	207
e33c267a RG	208	int shrinker_debugfs_rename(struct shrinker shrinker, const char fmt, ...)
	209	{
	210	struct dentry *entry;
	211	char buf[128];
	212	const char new, old;
	213	va_list ap;
	214	int ret = 0;
	215
	216	va_start(ap, fmt);
	217	new = kvasprintf_const(GFP_KERNEL, fmt, ap);
	218	va_end(ap);
	219
	220	if (!new)
	221	return -ENOMEM;
	222
	223	down_write(&shrinker_rwsem);
	224
	225	old = shrinker->name;
	226	shrinker->name = new;
	227
	228	if (shrinker->debugfs_entry) {
	229	snprintf(buf, sizeof(buf), "%s-%d", shrinker->name,
	230	shrinker->debugfs_id);
	231
	232	entry = debugfs_rename(shrinker_debugfs_root,
	233	shrinker->debugfs_entry,
	234	shrinker_debugfs_root, buf);
	235	if (IS_ERR(entry))
	236	ret = PTR_ERR(entry);
	237	else
	238	shrinker->debugfs_entry = entry;
	239	}
	240
	241	up_write(&shrinker_rwsem);
	242
	243	kfree_const(old);
	244
	245	return ret;
	246	}
	247	EXPORT_SYMBOL(shrinker_debugfs_rename);
	248
5035ebc6 RG	249	void shrinker_debugfs_remove(struct shrinker *shrinker)
	250	{
	251	lockdep_assert_held(&shrinker_rwsem);
	252
e33c267a	253	kfree_const(shrinker->name);
14773bfa	254	shrinker->name = NULL;
e33c267a	255
5035ebc6 RG	256	if (!shrinker->debugfs_entry)
	257	return;
	258
	259	debugfs_remove_recursive(shrinker->debugfs_entry);
	260	ida_free(&shrinker_debugfs_ida, shrinker->debugfs_id);
	261	}
	262
	263	static int __init shrinker_debugfs_init(void)
	264	{
	265	struct shrinker *shrinker;
	266	struct dentry *dentry;
	267	int ret = 0;
	268
	269	dentry = debugfs_create_dir("shrinker", NULL);
	270	if (IS_ERR(dentry))
	271	return PTR_ERR(dentry);
	272	shrinker_debugfs_root = dentry;
	273
	274	/* Create debugfs entries for shrinkers registered at boot */
	275	down_write(&shrinker_rwsem);
	276	list_for_each_entry(shrinker, &shrinker_list, list)
	277	if (!shrinker->debugfs_entry) {
	278	ret = shrinker_debugfs_add(shrinker);
	279	if (ret)
	280	break;
	281	}
	282	up_write(&shrinker_rwsem);
	283
	284	return ret;
	285	}
	286	late_initcall(shrinker_debugfs_init);