[linux.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);

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);
	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);

	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
102	int shrinker_debugfs_add(struct shrinker *shrinker)
103	{
104	struct dentry *entry;
e33c267a	105	char buf[128];
5035ebc6 RG	106	int id;
	107
	108	lockdep_assert_held(&shrinker_rwsem);
	109
	110	/* debugfs isn't initialized yet, add debugfs entries later. */
	111	if (!shrinker_debugfs_root)
	112	return 0;
	113
	114	id = ida_alloc(&shrinker_debugfs_ida, GFP_KERNEL);
	115	if (id < 0)
	116	return id;
	117	shrinker->debugfs_id = id;
	118
e33c267a	119	snprintf(buf, sizeof(buf), "%s-%d", shrinker->name, id);
5035ebc6 RG	120
	121	/* create debugfs entry */
	122	entry = debugfs_create_dir(buf, shrinker_debugfs_root);
	123	if (IS_ERR(entry)) {
	124	ida_free(&shrinker_debugfs_ida, id);
	125	return PTR_ERR(entry);
	126	}
	127	shrinker->debugfs_entry = entry;
	128
	129	debugfs_create_file("count", 0220, entry, shrinker,
	130	&shrinker_debugfs_count_fops);
	131	return 0;
	132	}
	133
e33c267a RG	134	int shrinker_debugfs_rename(struct shrinker shrinker, const char fmt, ...)
	135	{
	136	struct dentry *entry;
	137	char buf[128];
	138	const char new, old;
	139	va_list ap;
	140	int ret = 0;
	141
	142	va_start(ap, fmt);
	143	new = kvasprintf_const(GFP_KERNEL, fmt, ap);
	144	va_end(ap);
	145
	146	if (!new)
	147	return -ENOMEM;
	148
	149	down_write(&shrinker_rwsem);
	150
	151	old = shrinker->name;
	152	shrinker->name = new;
	153
	154	if (shrinker->debugfs_entry) {
	155	snprintf(buf, sizeof(buf), "%s-%d", shrinker->name,
	156	shrinker->debugfs_id);
	157
	158	entry = debugfs_rename(shrinker_debugfs_root,
	159	shrinker->debugfs_entry,
	160	shrinker_debugfs_root, buf);
	161	if (IS_ERR(entry))
	162	ret = PTR_ERR(entry);
	163	else
	164	shrinker->debugfs_entry = entry;
	165	}
	166
	167	up_write(&shrinker_rwsem);
	168
	169	kfree_const(old);
	170
	171	return ret;
	172	}
	173	EXPORT_SYMBOL(shrinker_debugfs_rename);
	174
5035ebc6 RG	175	void shrinker_debugfs_remove(struct shrinker *shrinker)
	176	{
	177	lockdep_assert_held(&shrinker_rwsem);
	178
e33c267a RG	179	kfree_const(shrinker->name);
e33c267a RG	180
5035ebc6 RG	181	if (!shrinker->debugfs_entry)
	182	return;
	183
	184	debugfs_remove_recursive(shrinker->debugfs_entry);
	185	ida_free(&shrinker_debugfs_ida, shrinker->debugfs_id);
	186	}
	187
	188	static int __init shrinker_debugfs_init(void)
	189	{
	190	struct shrinker *shrinker;
	191	struct dentry *dentry;
	192	int ret = 0;
	193
	194	dentry = debugfs_create_dir("shrinker", NULL);
	195	if (IS_ERR(dentry))
	196	return PTR_ERR(dentry);
	197	shrinker_debugfs_root = dentry;
	198
	199	/* Create debugfs entries for shrinkers registered at boot */
	200	down_write(&shrinker_rwsem);
	201	list_for_each_entry(shrinker, &shrinker_list, list)
	202	if (!shrinker->debugfs_entry) {
	203	ret = shrinker_debugfs_add(shrinker);
	204	if (ret)
	205	break;
	206	}
	207	up_write(&shrinker_rwsem);
	208
	209	return ret;
	210	}
	211	late_initcall(shrinker_debugfs_init);