[linux.git] / mm / hugetlb_cgroup.c

/*
 *
 * Copyright IBM Corporation, 2012
 * Author Aneesh Kumar K.V <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2.1 of the GNU Lesser General Public License
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 */

#include <linux/cgroup.h>
#include <linux/slab.h>
#include <linux/hugetlb.h>
#include <linux/hugetlb_cgroup.h>

struct hugetlb_cgroup {
	struct cgroup_subsys_state css;
	/*
	 * the counter to account for hugepages from hugetlb.
	 */
	struct res_counter hugepage[HUGE_MAX_HSTATE];
};

#define MEMFILE_PRIVATE(x, val)	(((x) << 16) | (val))
#define MEMFILE_IDX(val)	(((val) >> 16) & 0xffff)
#define MEMFILE_ATTR(val)	((val) & 0xffff)

struct cgroup_subsys hugetlb_subsys __read_mostly;
static struct hugetlb_cgroup *root_h_cgroup __read_mostly;

static inline
struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s)
{
	return container_of(s, struct hugetlb_cgroup, css);
}

static inline
struct hugetlb_cgroup *hugetlb_cgroup_from_cgroup(struct cgroup *cgroup)
{
	return hugetlb_cgroup_from_css(cgroup_subsys_state(cgroup,
							   hugetlb_subsys_id));
}

static inline
struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
{
	return hugetlb_cgroup_from_css(task_subsys_state(task,
							 hugetlb_subsys_id));
}

static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
{
	return (h_cg == root_h_cgroup);
}

static inline struct hugetlb_cgroup *parent_hugetlb_cgroup(struct cgroup *cg)
{
	if (!cg->parent)
		return NULL;
	return hugetlb_cgroup_from_cgroup(cg->parent);
}

static inline bool hugetlb_cgroup_have_usage(struct cgroup *cg)
{
	int idx;
	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cg);

	for (idx = 0; idx < hugetlb_max_hstate; idx++) {
		if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE)) > 0)
			return true;
	}
	return false;
}

static struct cgroup_subsys_state *hugetlb_cgroup_create(struct cgroup *cgroup)
{
	int idx;
	struct cgroup *parent_cgroup;
	struct hugetlb_cgroup *h_cgroup, *parent_h_cgroup;

	h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
	if (!h_cgroup)
		return ERR_PTR(-ENOMEM);

	parent_cgroup = cgroup->parent;
	if (parent_cgroup) {
		parent_h_cgroup = hugetlb_cgroup_from_cgroup(parent_cgroup);
		for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
			res_counter_init(&h_cgroup->hugepage[idx],
					 &parent_h_cgroup->hugepage[idx]);
	} else {
		root_h_cgroup = h_cgroup;
		for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
			res_counter_init(&h_cgroup->hugepage[idx], NULL);
	}
	return &h_cgroup->css;
}

static void hugetlb_cgroup_destroy(struct cgroup *cgroup)
{
	struct hugetlb_cgroup *h_cgroup;

	h_cgroup = hugetlb_cgroup_from_cgroup(cgroup);
	kfree(h_cgroup);
}


/*
 * Should be called with hugetlb_lock held.
 * Since we are holding hugetlb_lock, pages cannot get moved from
 * active list or uncharged from the cgroup, So no need to get
 * page reference and test for page active here. This function
 * cannot fail.
 */
static void hugetlb_cgroup_move_parent(int idx, struct cgroup *cgroup,
				       struct page *page)
{
	int csize;
	struct res_counter *counter;
	struct res_counter *fail_res;
	struct hugetlb_cgroup *page_hcg;
	struct hugetlb_cgroup *h_cg   = hugetlb_cgroup_from_cgroup(cgroup);
	struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(cgroup);

	page_hcg = hugetlb_cgroup_from_page(page);
	/*
	 * We can have pages in active list without any cgroup
	 * ie, hugepage with less than 3 pages. We can safely
	 * ignore those pages.
	 */
	if (!page_hcg || page_hcg != h_cg)
		goto out;

	csize = PAGE_SIZE << compound_order(page);
	if (!parent) {
		parent = root_h_cgroup;
		/* root has no limit */
		res_counter_charge_nofail(&parent->hugepage[idx],
					  csize, &fail_res);
	}
	counter = &h_cg->hugepage[idx];
	res_counter_uncharge_until(counter, counter->parent, csize);

	set_hugetlb_cgroup(page, parent);
out:
	return;
}

/*
 * Force the hugetlb cgroup to empty the hugetlb resources by moving them to
 * the parent cgroup.
 */
static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)
{
	struct hstate *h;
	struct page *page;
	int ret = 0, idx = 0;

	do {
		if (cgroup_task_count(cgroup) ||
		    !list_empty(&cgroup->children)) {
			ret = -EBUSY;
			goto out;
		}
		for_each_hstate(h) {
			spin_lock(&hugetlb_lock);
			list_for_each_entry(page, &h->hugepage_activelist, lru)
				hugetlb_cgroup_move_parent(idx, cgroup, page);

			spin_unlock(&hugetlb_lock);
			idx++;
		}
		cond_resched();
	} while (hugetlb_cgroup_have_usage(cgroup));
out:
	return ret;
}

int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
				 struct hugetlb_cgroup **ptr)
{
	int ret = 0;
	struct res_counter *fail_res;
	struct hugetlb_cgroup *h_cg = NULL;
	unsigned long csize = nr_pages * PAGE_SIZE;

	if (hugetlb_cgroup_disabled())
		goto done;
	/*
	 * We don't charge any cgroup if the compound page have less
	 * than 3 pages.
	 */
	if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
		goto done;
again:
	rcu_read_lock();
	h_cg = hugetlb_cgroup_from_task(current);
	if (!css_tryget(&h_cg->css)) {
		rcu_read_unlock();
		goto again;
	}
	rcu_read_unlock();

	ret = res_counter_charge(&h_cg->hugepage[idx], csize, &fail_res);
	css_put(&h_cg->css);
done:
	*ptr = h_cg;
	return ret;
}

/* Should be called with hugetlb_lock held */
void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
				  struct hugetlb_cgroup *h_cg,
				  struct page *page)
{
	if (hugetlb_cgroup_disabled() || !h_cg)
		return;

	set_hugetlb_cgroup(page, h_cg);
	return;
}

/*
 * Should be called with hugetlb_lock held
 */
void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
				  struct page *page)
{
	struct hugetlb_cgroup *h_cg;
	unsigned long csize = nr_pages * PAGE_SIZE;

	if (hugetlb_cgroup_disabled())
		return;
	VM_BUG_ON(!spin_is_locked(&hugetlb_lock));
	h_cg = hugetlb_cgroup_from_page(page);
	if (unlikely(!h_cg))
		return;
	set_hugetlb_cgroup(page, NULL);
	res_counter_uncharge(&h_cg->hugepage[idx], csize);
	return;
}

void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
				    struct hugetlb_cgroup *h_cg)
{
	unsigned long csize = nr_pages * PAGE_SIZE;

	if (hugetlb_cgroup_disabled() || !h_cg)
		return;

	if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
		return;

	res_counter_uncharge(&h_cg->hugepage[idx], csize);
	return;
}

static ssize_t hugetlb_cgroup_read(struct cgroup *cgroup, struct cftype *cft,
				   struct file *file, char __user *buf,
				   size_t nbytes, loff_t *ppos)
{
	u64 val;
	char str[64];
	int idx, name, len;
	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);

	idx = MEMFILE_IDX(cft->private);
	name = MEMFILE_ATTR(cft->private);

	val = res_counter_read_u64(&h_cg->hugepage[idx], name);
	len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
	return simple_read_from_buffer(buf, nbytes, ppos, str, len);
}

static int hugetlb_cgroup_write(struct cgroup *cgroup, struct cftype *cft,
				const char *buffer)
{
	int idx, name, ret;
	unsigned long long val;
	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);

	idx = MEMFILE_IDX(cft->private);
	name = MEMFILE_ATTR(cft->private);

	switch (name) {
	case RES_LIMIT:
		if (hugetlb_cgroup_is_root(h_cg)) {
			/* Can't set limit on root */
			ret = -EINVAL;
			break;
		}
		/* This function does all necessary parse...reuse it */
		ret = res_counter_memparse_write_strategy(buffer, &val);
		if (ret)
			break;
		ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
		break;
	default:
		ret = -EINVAL;
		break;
	}
	return ret;
}

static int hugetlb_cgroup_reset(struct cgroup *cgroup, unsigned int event)
{
	int idx, name, ret = 0;
	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);

	idx = MEMFILE_IDX(event);
	name = MEMFILE_ATTR(event);

	switch (name) {
	case RES_MAX_USAGE:
		res_counter_reset_max(&h_cg->hugepage[idx]);
		break;
	case RES_FAILCNT:
		res_counter_reset_failcnt(&h_cg->hugepage[idx]);
		break;
	default:
		ret = -EINVAL;
		break;
	}
	return ret;
}

static char *mem_fmt(char *buf, int size, unsigned long hsize)
{
	if (hsize >= (1UL << 30))
		snprintf(buf, size, "%luGB", hsize >> 30);
	else if (hsize >= (1UL << 20))
		snprintf(buf, size, "%luMB", hsize >> 20);
	else
		snprintf(buf, size, "%luKB", hsize >> 10);
	return buf;
}

int __init hugetlb_cgroup_file_init(int idx)
{
	char buf[32];
	struct cftype *cft;
	struct hstate *h = &hstates[idx];

	/* format the size */
	mem_fmt(buf, 32, huge_page_size(h));

	/* Add the limit file */
	cft = &h->cgroup_files[0];
	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
	cft->read = hugetlb_cgroup_read;
	cft->write_string = hugetlb_cgroup_write;

	/* Add the usage file */
	cft = &h->cgroup_files[1];
	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
	cft->read = hugetlb_cgroup_read;

	/* Add the MAX usage file */
	cft = &h->cgroup_files[2];
	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
	cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
	cft->trigger = hugetlb_cgroup_reset;
	cft->read = hugetlb_cgroup_read;

	/* Add the failcntfile */
	cft = &h->cgroup_files[3];
	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
	cft->private  = MEMFILE_PRIVATE(idx, RES_FAILCNT);
	cft->trigger  = hugetlb_cgroup_reset;
	cft->read = hugetlb_cgroup_read;

	/* NULL terminate the last cft */
	cft = &h->cgroup_files[4];
	memset(cft, 0, sizeof(*cft));

	WARN_ON(cgroup_add_cftypes(&hugetlb_subsys, h->cgroup_files));

	return 0;
}

/*
 * hugetlb_lock will make sure a parallel cgroup rmdir won't happen
 * when we migrate hugepages
 */
void hugetlb_cgroup_migrate(struct page *oldhpage, struct page *newhpage)
{
	struct hugetlb_cgroup *h_cg;
	struct hstate *h = page_hstate(oldhpage);

	if (hugetlb_cgroup_disabled())
		return;

	VM_BUG_ON(!PageHuge(oldhpage));
	spin_lock(&hugetlb_lock);
	h_cg = hugetlb_cgroup_from_page(oldhpage);
	set_hugetlb_cgroup(oldhpage, NULL);

	/* move the h_cg details to new cgroup */
	set_hugetlb_cgroup(newhpage, h_cg);
	list_move(&newhpage->lru, &h->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	return;
}

struct cgroup_subsys hugetlb_subsys = {
	.name = "hugetlb",
	.create     = hugetlb_cgroup_create,
	.pre_destroy = hugetlb_cgroup_pre_destroy,
	.destroy    = hugetlb_cgroup_destroy,
	.subsys_id  = hugetlb_subsys_id,
};
Commit	Line	Data
2bc64a20 AK	1	/*
	2	*
	3	* Copyright IBM Corporation, 2012
	4	* Author Aneesh Kumar K.V <[email protected]>
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of version 2.1 of the GNU Lesser General Public License
	8	* as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it would be useful, but
	11	* WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
	13	*
	14	*/
	15
	16	#include <linux/cgroup.h>
	17	#include <linux/slab.h>
	18	#include <linux/hugetlb.h>
	19	#include <linux/hugetlb_cgroup.h>
	20
	21	struct hugetlb_cgroup {
	22	struct cgroup_subsys_state css;
	23	/*
	24	* the counter to account for hugepages from hugetlb.
	25	*/
	26	struct res_counter hugepage[HUGE_MAX_HSTATE];
	27	};
	28
abb8206c AK	29	#define MEMFILE_PRIVATE(x, val) (((x) << 16) \| (val))
	30	#define MEMFILE_IDX(val) (((val) >> 16) & 0xffff)
	31	#define MEMFILE_ATTR(val) ((val) & 0xffff)
	32
2bc64a20 AK	33	struct cgroup_subsys hugetlb_subsys __read_mostly;
	34	static struct hugetlb_cgroup *root_h_cgroup __read_mostly;
	35
	36	static inline
	37	struct hugetlb_cgroup hugetlb_cgroup_from_css(struct cgroup_subsys_state s)
	38	{
	39	return container_of(s, struct hugetlb_cgroup, css);
	40	}
	41
	42	static inline
	43	struct hugetlb_cgroup hugetlb_cgroup_from_cgroup(struct cgroup cgroup)
	44	{
	45	return hugetlb_cgroup_from_css(cgroup_subsys_state(cgroup,
	46	hugetlb_subsys_id));
	47	}
	48
	49	static inline
	50	struct hugetlb_cgroup hugetlb_cgroup_from_task(struct task_struct task)
	51	{
	52	return hugetlb_cgroup_from_css(task_subsys_state(task,
	53	hugetlb_subsys_id));
	54	}
	55
	56	static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
	57	{
	58	return (h_cg == root_h_cgroup);
	59	}
	60
	61	static inline struct hugetlb_cgroup parent_hugetlb_cgroup(struct cgroup cg)
	62	{
	63	if (!cg->parent)
	64	return NULL;
	65	return hugetlb_cgroup_from_cgroup(cg->parent);
	66	}
	67
	68	static inline bool hugetlb_cgroup_have_usage(struct cgroup *cg)
	69	{
	70	int idx;
	71	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cg);
	72
	73	for (idx = 0; idx < hugetlb_max_hstate; idx++) {
	74	if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE)) > 0)
	75	return true;
	76	}
	77	return false;
	78	}
	79
	80	static struct cgroup_subsys_state hugetlb_cgroup_create(struct cgroup cgroup)
	81	{
	82	int idx;
	83	struct cgroup *parent_cgroup;
	84	struct hugetlb_cgroup h_cgroup, parent_h_cgroup;
	85
	86	h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
	87	if (!h_cgroup)
	88	return ERR_PTR(-ENOMEM);
	89
	90	parent_cgroup = cgroup->parent;
	91	if (parent_cgroup) {
	92	parent_h_cgroup = hugetlb_cgroup_from_cgroup(parent_cgroup);
	93	for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
	94	res_counter_init(&h_cgroup->hugepage[idx],
	95	&parent_h_cgroup->hugepage[idx]);
	96	} else {
97	root_h_cgroup = h_cgroup;
98	for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
99	res_counter_init(&h_cgroup->hugepage[idx], NULL);
100	}
101	return &h_cgroup->css;
102	}
103
104	static void hugetlb_cgroup_destroy(struct cgroup *cgroup)
105	{
106	struct hugetlb_cgroup *h_cgroup;
107
108	h_cgroup = hugetlb_cgroup_from_cgroup(cgroup);
109	kfree(h_cgroup);
110	}
111
da1def55 AK	112
	113	/*
	114	* Should be called with hugetlb_lock held.
	115	* Since we are holding hugetlb_lock, pages cannot get moved from
	116	* active list or uncharged from the cgroup, So no need to get
	117	* page reference and test for page active here. This function
	118	* cannot fail.
	119	*/
	120	static void hugetlb_cgroup_move_parent(int idx, struct cgroup *cgroup,
	121	struct page *page)
	122	{
	123	int csize;
	124	struct res_counter *counter;
	125	struct res_counter *fail_res;
	126	struct hugetlb_cgroup *page_hcg;
	127	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
	128	struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(cgroup);
	129
	130	page_hcg = hugetlb_cgroup_from_page(page);
	131	/*
	132	* We can have pages in active list without any cgroup
	133	* ie, hugepage with less than 3 pages. We can safely
	134	* ignore those pages.
	135	*/
	136	if (!page_hcg \|\| page_hcg != h_cg)
	137	goto out;
	138
	139	csize = PAGE_SIZE << compound_order(page);
	140	if (!parent) {
	141	parent = root_h_cgroup;
	142	/* root has no limit */
	143	res_counter_charge_nofail(&parent->hugepage[idx],
	144	csize, &fail_res);
	145	}
	146	counter = &h_cg->hugepage[idx];
	147	res_counter_uncharge_until(counter, counter->parent, csize);
	148
	149	set_hugetlb_cgroup(page, parent);
	150	out:
	151	return;
	152	}
	153
	154	/*
	155	* Force the hugetlb cgroup to empty the hugetlb resources by moving them to
	156	* the parent cgroup.
	157	*/
2bc64a20 AK	158	static int hugetlb_cgroup_pre_destroy(struct cgroup *cgroup)
2bc64a20 AK	159	{
da1def55 AK	160	struct hstate *h;
	161	struct page *page;
	162	int ret = 0, idx = 0;
	163
	164	do {
	165	if (cgroup_task_count(cgroup) \|\|
	166	!list_empty(&cgroup->children)) {
	167	ret = -EBUSY;
	168	goto out;
	169	}
	170	for_each_hstate(h) {
	171	spin_lock(&hugetlb_lock);
	172	list_for_each_entry(page, &h->hugepage_activelist, lru)
	173	hugetlb_cgroup_move_parent(idx, cgroup, page);
	174
	175	spin_unlock(&hugetlb_lock);
	176	idx++;
	177	}
	178	cond_resched();
	179	} while (hugetlb_cgroup_have_usage(cgroup));
	180	out:
	181	return ret;
2bc64a20 AK	182	}
2bc64a20 AK	183
6d76dcf4 AK	184	int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
	185	struct hugetlb_cgroup **ptr)
	186	{
	187	int ret = 0;
	188	struct res_counter *fail_res;
	189	struct hugetlb_cgroup *h_cg = NULL;
	190	unsigned long csize = nr_pages * PAGE_SIZE;
	191
	192	if (hugetlb_cgroup_disabled())
	193	goto done;
	194	/*
	195	* We don't charge any cgroup if the compound page have less
	196	* than 3 pages.
	197	*/
	198	if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
	199	goto done;
	200	again:
	201	rcu_read_lock();
	202	h_cg = hugetlb_cgroup_from_task(current);
	203	if (!css_tryget(&h_cg->css)) {
	204	rcu_read_unlock();
	205	goto again;
	206	}
	207	rcu_read_unlock();
	208
	209	ret = res_counter_charge(&h_cg->hugepage[idx], csize, &fail_res);
	210	css_put(&h_cg->css);
	211	done:
	212	*ptr = h_cg;
	213	return ret;
	214	}
	215
94ae8ba7	216	/* Should be called with hugetlb_lock held */
6d76dcf4 AK	217	void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
	218	struct hugetlb_cgroup *h_cg,
	219	struct page *page)
	220	{
	221	if (hugetlb_cgroup_disabled() \|\| !h_cg)
	222	return;
	223
6d76dcf4	224	set_hugetlb_cgroup(page, h_cg);
6d76dcf4 AK	225	return;
	226	}
	227
	228	/*
	229	* Should be called with hugetlb_lock held
	230	*/
	231	void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
	232	struct page *page)
	233	{
	234	struct hugetlb_cgroup *h_cg;
	235	unsigned long csize = nr_pages * PAGE_SIZE;
	236
	237	if (hugetlb_cgroup_disabled())
	238	return;
	239	VM_BUG_ON(!spin_is_locked(&hugetlb_lock));
	240	h_cg = hugetlb_cgroup_from_page(page);
	241	if (unlikely(!h_cg))
	242	return;
	243	set_hugetlb_cgroup(page, NULL);
	244	res_counter_uncharge(&h_cg->hugepage[idx], csize);
	245	return;
	246	}
	247
	248	void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
	249	struct hugetlb_cgroup *h_cg)
	250	{
	251	unsigned long csize = nr_pages * PAGE_SIZE;
	252
	253	if (hugetlb_cgroup_disabled() \|\| !h_cg)
	254	return;
	255
	256	if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
	257	return;
	258
	259	res_counter_uncharge(&h_cg->hugepage[idx], csize);
	260	return;
	261	}
	262
abb8206c AK	263	static ssize_t hugetlb_cgroup_read(struct cgroup cgroup, struct cftype cft,
	264	struct file file, char __user buf,
	265	size_t nbytes, loff_t *ppos)
	266	{
	267	u64 val;
	268	char str[64];
	269	int idx, name, len;
	270	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
	271
	272	idx = MEMFILE_IDX(cft->private);
	273	name = MEMFILE_ATTR(cft->private);
	274
	275	val = res_counter_read_u64(&h_cg->hugepage[idx], name);
	276	len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
	277	return simple_read_from_buffer(buf, nbytes, ppos, str, len);
	278	}
	279
	280	static int hugetlb_cgroup_write(struct cgroup cgroup, struct cftype cft,
	281	const char *buffer)
	282	{
	283	int idx, name, ret;
	284	unsigned long long val;
	285	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
	286
	287	idx = MEMFILE_IDX(cft->private);
	288	name = MEMFILE_ATTR(cft->private);
	289
	290	switch (name) {
	291	case RES_LIMIT:
	292	if (hugetlb_cgroup_is_root(h_cg)) {
	293	/* Can't set limit on root */
	294	ret = -EINVAL;
	295	break;
	296	}
	297	/* This function does all necessary parse...reuse it */
	298	ret = res_counter_memparse_write_strategy(buffer, &val);
	299	if (ret)
	300	break;
	301	ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
	302	break;
	303	default:
	304	ret = -EINVAL;
	305	break;
	306	}
	307	return ret;
	308	}
	309
	310	static int hugetlb_cgroup_reset(struct cgroup *cgroup, unsigned int event)
	311	{
	312	int idx, name, ret = 0;
	313	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
	314
	315	idx = MEMFILE_IDX(event);
	316	name = MEMFILE_ATTR(event);
	317
	318	switch (name) {
	319	case RES_MAX_USAGE:
	320	res_counter_reset_max(&h_cg->hugepage[idx]);
	321	break;
	322	case RES_FAILCNT:
	323	res_counter_reset_failcnt(&h_cg->hugepage[idx]);
	324	break;
	325	default:
	326	ret = -EINVAL;
327	break;
328	}
329	return ret;
330	}
331
332	static char mem_fmt(char buf, int size, unsigned long hsize)
333	{
334	if (hsize >= (1UL << 30))
335	snprintf(buf, size, "%luGB", hsize >> 30);
336	else if (hsize >= (1UL << 20))
337	snprintf(buf, size, "%luMB", hsize >> 20);
338	else
339	snprintf(buf, size, "%luKB", hsize >> 10);
340	return buf;
341	}
342
343	int __init hugetlb_cgroup_file_init(int idx)
344	{
345	char buf[32];
346	struct cftype *cft;
347	struct hstate *h = &hstates[idx];
348
349	/* format the size */
350	mem_fmt(buf, 32, huge_page_size(h));
351
352	/* Add the limit file */
353	cft = &h->cgroup_files[0];
354	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
355	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
356	cft->read = hugetlb_cgroup_read;
357	cft->write_string = hugetlb_cgroup_write;
358
359	/* Add the usage file */
360	cft = &h->cgroup_files[1];
361	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
362	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
363	cft->read = hugetlb_cgroup_read;
364
365	/* Add the MAX usage file */
366	cft = &h->cgroup_files[2];
367	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
368	cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
369	cft->trigger = hugetlb_cgroup_reset;
370	cft->read = hugetlb_cgroup_read;
371
372	/* Add the failcntfile */
373	cft = &h->cgroup_files[3];
374	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
375	cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT);
376	cft->trigger = hugetlb_cgroup_reset;
377	cft->read = hugetlb_cgroup_read;
378
379	/* NULL terminate the last cft */
380	cft = &h->cgroup_files[4];
381	memset(cft, 0, sizeof(*cft));
382
383	WARN_ON(cgroup_add_cftypes(&hugetlb_subsys, h->cgroup_files));
384
385	return 0;
386	}
387
75754681 AK	388	/*
	389	* hugetlb_lock will make sure a parallel cgroup rmdir won't happen
	390	* when we migrate hugepages
	391	*/
8e6ac7fa AK	392	void hugetlb_cgroup_migrate(struct page oldhpage, struct page newhpage)
	393	{
	394	struct hugetlb_cgroup *h_cg;
94ae8ba7	395	struct hstate *h = page_hstate(oldhpage);
8e6ac7fa AK	396
	397	if (hugetlb_cgroup_disabled())
	398	return;
	399
	400	VM_BUG_ON(!PageHuge(oldhpage));
	401	spin_lock(&hugetlb_lock);
	402	h_cg = hugetlb_cgroup_from_page(oldhpage);
	403	set_hugetlb_cgroup(oldhpage, NULL);
8e6ac7fa AK	404
	405	/* move the h_cg details to new cgroup */
	406	set_hugetlb_cgroup(newhpage, h_cg);
94ae8ba7	407	list_move(&newhpage->lru, &h->hugepage_activelist);
8e6ac7fa	408	spin_unlock(&hugetlb_lock);
8e6ac7fa AK	409	return;
	410	}
	411
2bc64a20 AK	412	struct cgroup_subsys hugetlb_subsys = {
	413	.name = "hugetlb",
	414	.create = hugetlb_cgroup_create,
	415	.pre_destroy = hugetlb_cgroup_pre_destroy,
	416	.destroy = hugetlb_cgroup_destroy,
	417	.subsys_id = hugetlb_subsys_id,
	418	};