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/*
*
* 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_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,
};
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