[deliverable/linux.git] / mm / hugetlb_cgroup.c

/*
 *
 * Copyright IBM Corporation, 2012
 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
 *
 * 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_css(cgroup, hugetlb_subsys_id));
}

static inline
struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
{
	return hugetlb_cgroup_from_css(task_css(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_css_alloc(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_css_free(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 void hugetlb_cgroup_css_offline(struct cgroup *cgroup)
{
	struct hstate *h;
	struct page *page;
	int idx = 0;

	do {
		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));
}

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;
}

static void __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;
}

void __init hugetlb_cgroup_file_init(void)
{
	struct hstate *h;

	for_each_hstate(h) {
		/*
		 * Add cgroup control files only if the huge page consists
		 * of more than two normal pages. This is because we use
		 * page[2].lru.next for storing cgroup details.
		 */
		if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
			__hugetlb_cgroup_file_init(hstate_index(h));
	}
}

/*
 * 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",
	.css_alloc	= hugetlb_cgroup_css_alloc,
	.css_offline	= hugetlb_cgroup_css_offline,
	.css_free	= hugetlb_cgroup_css_free,
	.subsys_id	= hugetlb_subsys_id,
};
Commit	Line	Data
2bc64a20 AK	1	/*
	2	*
	3	* Copyright IBM Corporation, 2012
	4	* Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
	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	{
8af01f56	45	return hugetlb_cgroup_from_css(cgroup_css(cgroup, hugetlb_subsys_id));
2bc64a20 AK	46	}
	47
	48	static inline
	49	struct hugetlb_cgroup hugetlb_cgroup_from_task(struct task_struct task)
	50	{
8af01f56	51	return hugetlb_cgroup_from_css(task_css(task, hugetlb_subsys_id));
2bc64a20 AK	52	}
	53
	54	static inline bool hugetlb_cgroup_is_root(struct hugetlb_cgroup *h_cg)
	55	{
	56	return (h_cg == root_h_cgroup);
	57	}
	58
	59	static inline struct hugetlb_cgroup parent_hugetlb_cgroup(struct cgroup cg)
	60	{
	61	if (!cg->parent)
	62	return NULL;
	63	return hugetlb_cgroup_from_cgroup(cg->parent);
	64	}
	65
	66	static inline bool hugetlb_cgroup_have_usage(struct cgroup *cg)
	67	{
	68	int idx;
	69	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cg);
	70
	71	for (idx = 0; idx < hugetlb_max_hstate; idx++) {
	72	if ((res_counter_read_u64(&h_cg->hugepage[idx], RES_USAGE)) > 0)
	73	return true;
	74	}
	75	return false;
	76	}
	77
92fb9748	78	static struct cgroup_subsys_state hugetlb_cgroup_css_alloc(struct cgroup cgroup)
2bc64a20 AK	79	{
	80	int idx;
	81	struct cgroup *parent_cgroup;
	82	struct hugetlb_cgroup h_cgroup, parent_h_cgroup;
	83
	84	h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
	85	if (!h_cgroup)
	86	return ERR_PTR(-ENOMEM);
	87
	88	parent_cgroup = cgroup->parent;
	89	if (parent_cgroup) {
	90	parent_h_cgroup = hugetlb_cgroup_from_cgroup(parent_cgroup);
	91	for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
	92	res_counter_init(&h_cgroup->hugepage[idx],
	93	&parent_h_cgroup->hugepage[idx]);
	94	} else {
	95	root_h_cgroup = h_cgroup;
	96	for (idx = 0; idx < HUGE_MAX_HSTATE; idx++)
	97	res_counter_init(&h_cgroup->hugepage[idx], NULL);
	98	}
	99	return &h_cgroup->css;
	100	}
	101
92fb9748	102	static void hugetlb_cgroup_css_free(struct cgroup *cgroup)
2bc64a20 AK	103	{
	104	struct hugetlb_cgroup *h_cgroup;
	105
	106	h_cgroup = hugetlb_cgroup_from_cgroup(cgroup);
	107	kfree(h_cgroup);
	108	}
	109
da1def55 AK	110
	111	/*
	112	* Should be called with hugetlb_lock held.
	113	* Since we are holding hugetlb_lock, pages cannot get moved from
	114	* active list or uncharged from the cgroup, So no need to get
	115	* page reference and test for page active here. This function
	116	* cannot fail.
	117	*/
	118	static void hugetlb_cgroup_move_parent(int idx, struct cgroup *cgroup,
	119	struct page *page)
	120	{
	121	int csize;
	122	struct res_counter *counter;
	123	struct res_counter *fail_res;
	124	struct hugetlb_cgroup *page_hcg;
	125	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
	126	struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(cgroup);
	127
	128	page_hcg = hugetlb_cgroup_from_page(page);
	129	/*
	130	* We can have pages in active list without any cgroup
	131	* ie, hugepage with less than 3 pages. We can safely
	132	* ignore those pages.
	133	*/
	134	if (!page_hcg \|\| page_hcg != h_cg)
	135	goto out;
	136
	137	csize = PAGE_SIZE << compound_order(page);
	138	if (!parent) {
	139	parent = root_h_cgroup;
	140	/* root has no limit */
	141	res_counter_charge_nofail(&parent->hugepage[idx],
	142	csize, &fail_res);
	143	}
	144	counter = &h_cg->hugepage[idx];
	145	res_counter_uncharge_until(counter, counter->parent, csize);
	146
	147	set_hugetlb_cgroup(page, parent);
	148	out:
	149	return;
	150	}
	151
	152	/*
	153	* Force the hugetlb cgroup to empty the hugetlb resources by moving them to
	154	* the parent cgroup.
	155	*/
92fb9748	156	static void hugetlb_cgroup_css_offline(struct cgroup *cgroup)
2bc64a20	157	{
da1def55 AK	158	struct hstate *h;
da1def55 AK	159	struct page *page;
9d093cb1	160	int idx = 0;
da1def55 AK	161
da1def55 AK	162	do {
da1def55 AK	163	for_each_hstate(h) {
	164	spin_lock(&hugetlb_lock);
	165	list_for_each_entry(page, &h->hugepage_activelist, lru)
	166	hugetlb_cgroup_move_parent(idx, cgroup, page);
	167
	168	spin_unlock(&hugetlb_lock);
	169	idx++;
	170	}
	171	cond_resched();
	172	} while (hugetlb_cgroup_have_usage(cgroup));
2bc64a20 AK	173	}
2bc64a20 AK	174
6d76dcf4 AK	175	int hugetlb_cgroup_charge_cgroup(int idx, unsigned long nr_pages,
	176	struct hugetlb_cgroup **ptr)
	177	{
	178	int ret = 0;
	179	struct res_counter *fail_res;
	180	struct hugetlb_cgroup *h_cg = NULL;
	181	unsigned long csize = nr_pages * PAGE_SIZE;
	182
	183	if (hugetlb_cgroup_disabled())
	184	goto done;
	185	/*
	186	* We don't charge any cgroup if the compound page have less
	187	* than 3 pages.
	188	*/
	189	if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
	190	goto done;
	191	again:
	192	rcu_read_lock();
	193	h_cg = hugetlb_cgroup_from_task(current);
	194	if (!css_tryget(&h_cg->css)) {
	195	rcu_read_unlock();
	196	goto again;
	197	}
	198	rcu_read_unlock();
	199
	200	ret = res_counter_charge(&h_cg->hugepage[idx], csize, &fail_res);
	201	css_put(&h_cg->css);
	202	done:
	203	*ptr = h_cg;
	204	return ret;
	205	}
	206
94ae8ba7	207	/* Should be called with hugetlb_lock held */
6d76dcf4 AK	208	void hugetlb_cgroup_commit_charge(int idx, unsigned long nr_pages,
	209	struct hugetlb_cgroup *h_cg,
	210	struct page *page)
	211	{
	212	if (hugetlb_cgroup_disabled() \|\| !h_cg)
	213	return;
	214
6d76dcf4	215	set_hugetlb_cgroup(page, h_cg);
6d76dcf4 AK	216	return;
	217	}
	218
	219	/*
	220	* Should be called with hugetlb_lock held
	221	*/
	222	void hugetlb_cgroup_uncharge_page(int idx, unsigned long nr_pages,
	223	struct page *page)
	224	{
	225	struct hugetlb_cgroup *h_cg;
	226	unsigned long csize = nr_pages * PAGE_SIZE;
	227
	228	if (hugetlb_cgroup_disabled())
	229	return;
	230	VM_BUG_ON(!spin_is_locked(&hugetlb_lock));
	231	h_cg = hugetlb_cgroup_from_page(page);
	232	if (unlikely(!h_cg))
	233	return;
	234	set_hugetlb_cgroup(page, NULL);
	235	res_counter_uncharge(&h_cg->hugepage[idx], csize);
	236	return;
	237	}
	238
	239	void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
	240	struct hugetlb_cgroup *h_cg)
	241	{
	242	unsigned long csize = nr_pages * PAGE_SIZE;
	243
	244	if (hugetlb_cgroup_disabled() \|\| !h_cg)
	245	return;
	246
	247	if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
	248	return;
	249
	250	res_counter_uncharge(&h_cg->hugepage[idx], csize);
	251	return;
	252	}
	253
abb8206c AK	254	static ssize_t hugetlb_cgroup_read(struct cgroup cgroup, struct cftype cft,
	255	struct file file, char __user buf,
	256	size_t nbytes, loff_t *ppos)
	257	{
	258	u64 val;
	259	char str[64];
	260	int idx, name, len;
	261	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
	262
	263	idx = MEMFILE_IDX(cft->private);
	264	name = MEMFILE_ATTR(cft->private);
	265
	266	val = res_counter_read_u64(&h_cg->hugepage[idx], name);
	267	len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
	268	return simple_read_from_buffer(buf, nbytes, ppos, str, len);
	269	}
	270
	271	static int hugetlb_cgroup_write(struct cgroup cgroup, struct cftype cft,
	272	const char *buffer)
	273	{
	274	int idx, name, ret;
	275	unsigned long long val;
	276	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
	277
	278	idx = MEMFILE_IDX(cft->private);
	279	name = MEMFILE_ATTR(cft->private);
	280
	281	switch (name) {
	282	case RES_LIMIT:
	283	if (hugetlb_cgroup_is_root(h_cg)) {
	284	/* Can't set limit on root */
	285	ret = -EINVAL;
	286	break;
	287	}
	288	/* This function does all necessary parse...reuse it */
	289	ret = res_counter_memparse_write_strategy(buffer, &val);
	290	if (ret)
	291	break;
	292	ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
	293	break;
	294	default:
	295	ret = -EINVAL;
	296	break;
	297	}
	298	return ret;
	299	}
	300
	301	static int hugetlb_cgroup_reset(struct cgroup *cgroup, unsigned int event)
	302	{
	303	int idx, name, ret = 0;
	304	struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_cgroup(cgroup);
	305
	306	idx = MEMFILE_IDX(event);
	307	name = MEMFILE_ATTR(event);
	308
	309	switch (name) {
	310	case RES_MAX_USAGE:
	311	res_counter_reset_max(&h_cg->hugepage[idx]);
	312	break;
	313	case RES_FAILCNT:
	314	res_counter_reset_failcnt(&h_cg->hugepage[idx]);
	315	break;
	316	default:
	317	ret = -EINVAL;
318	break;
319	}
320	return ret;
321	}
322
323	static char mem_fmt(char buf, int size, unsigned long hsize)
324	{
325	if (hsize >= (1UL << 30))
326	snprintf(buf, size, "%luGB", hsize >> 30);
327	else if (hsize >= (1UL << 20))
328	snprintf(buf, size, "%luMB", hsize >> 20);
329	else
330	snprintf(buf, size, "%luKB", hsize >> 10);
331	return buf;
332	}
333
7179e7bf	334	static void __init __hugetlb_cgroup_file_init(int idx)
abb8206c AK	335	{
	336	char buf[32];
	337	struct cftype *cft;
	338	struct hstate *h = &hstates[idx];
	339
	340	/* format the size */
	341	mem_fmt(buf, 32, huge_page_size(h));
	342
	343	/* Add the limit file */
	344	cft = &h->cgroup_files[0];
	345	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.limit_in_bytes", buf);
	346	cft->private = MEMFILE_PRIVATE(idx, RES_LIMIT);
	347	cft->read = hugetlb_cgroup_read;
	348	cft->write_string = hugetlb_cgroup_write;
	349
	350	/* Add the usage file */
	351	cft = &h->cgroup_files[1];
	352	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.usage_in_bytes", buf);
	353	cft->private = MEMFILE_PRIVATE(idx, RES_USAGE);
	354	cft->read = hugetlb_cgroup_read;
	355
	356	/* Add the MAX usage file */
	357	cft = &h->cgroup_files[2];
	358	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.max_usage_in_bytes", buf);
	359	cft->private = MEMFILE_PRIVATE(idx, RES_MAX_USAGE);
	360	cft->trigger = hugetlb_cgroup_reset;
	361	cft->read = hugetlb_cgroup_read;
	362
	363	/* Add the failcntfile */
	364	cft = &h->cgroup_files[3];
	365	snprintf(cft->name, MAX_CFTYPE_NAME, "%s.failcnt", buf);
	366	cft->private = MEMFILE_PRIVATE(idx, RES_FAILCNT);
	367	cft->trigger = hugetlb_cgroup_reset;
	368	cft->read = hugetlb_cgroup_read;
	369
	370	/* NULL terminate the last cft */
	371	cft = &h->cgroup_files[4];
	372	memset(cft, 0, sizeof(*cft));
	373
	374	WARN_ON(cgroup_add_cftypes(&hugetlb_subsys, h->cgroup_files));
	375
7179e7bf JW	376	return;
	377	}
	378
	379	void __init hugetlb_cgroup_file_init(void)
	380	{
	381	struct hstate *h;
	382
	383	for_each_hstate(h) {
	384	/*
	385	* Add cgroup control files only if the huge page consists
	386	* of more than two normal pages. This is because we use
	387	* page[2].lru.next for storing cgroup details.
	388	*/
	389	if (huge_page_order(h) >= HUGETLB_CGROUP_MIN_ORDER)
	390	__hugetlb_cgroup_file_init(hstate_index(h));
	391	}
abb8206c AK	392	}
abb8206c AK	393
75754681 AK	394	/*
	395	* hugetlb_lock will make sure a parallel cgroup rmdir won't happen
	396	* when we migrate hugepages
	397	*/
8e6ac7fa AK	398	void hugetlb_cgroup_migrate(struct page oldhpage, struct page newhpage)
	399	{
	400	struct hugetlb_cgroup *h_cg;
94ae8ba7	401	struct hstate *h = page_hstate(oldhpage);
8e6ac7fa AK	402
	403	if (hugetlb_cgroup_disabled())
	404	return;
	405
	406	VM_BUG_ON(!PageHuge(oldhpage));
	407	spin_lock(&hugetlb_lock);
	408	h_cg = hugetlb_cgroup_from_page(oldhpage);
	409	set_hugetlb_cgroup(oldhpage, NULL);
8e6ac7fa AK	410
	411	/* move the h_cg details to new cgroup */
	412	set_hugetlb_cgroup(newhpage, h_cg);
94ae8ba7	413	list_move(&newhpage->lru, &h->hugepage_activelist);
8e6ac7fa	414	spin_unlock(&hugetlb_lock);
8e6ac7fa AK	415	return;
	416	}
	417
2bc64a20 AK	418	struct cgroup_subsys hugetlb_subsys = {
2bc64a20 AK	419	.name = "hugetlb",
92fb9748 TH	420	.css_alloc = hugetlb_cgroup_css_alloc,
	421	.css_offline = hugetlb_cgroup_css_offline,
	422	.css_free = hugetlb_cgroup_css_free,
	423	.subsys_id = hugetlb_subsys_id,
2bc64a20	424	};