linux/mm/hugetlb_cgroup.c
Tejun Heo 2cf669a58d cgroup: replace cgroup_add_cftypes() with cgroup_add_legacy_cftypes()
Currently, cftypes added by cgroup_add_cftypes() are used for both the
unified default hierarchy and legacy ones and subsystems can mark each
file with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to
appear only on one of them.  This is quite hairy and error-prone.
Also, we may end up exposing interface files to the default hierarchy
without thinking it through.

cgroup_subsys will grow two separate cftype addition functions and
apply each only on the hierarchies of the matching type.  This will
allow organizing cftypes in a lot clearer way and encourage subsystems
to scrutinize the interface which is being exposed in the new default
hierarchy.

In preparation, this patch adds cgroup_add_legacy_cftypes() which
currently is a simple wrapper around cgroup_add_cftypes() and replaces
all cgroup_add_cftypes() usages with it.

While at it, this patch drops a completely spurious return from
__hugetlb_cgroup_file_init().

This patch doesn't introduce any functional differences.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2014-07-15 11:05:09 -04:00

409 lines
10 KiB
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)
static struct hugetlb_cgroup *root_h_cgroup __read_mostly;
static inline
struct hugetlb_cgroup *hugetlb_cgroup_from_css(struct cgroup_subsys_state *s)
{
return s ? container_of(s, struct hugetlb_cgroup, css) : NULL;
}
static inline
struct hugetlb_cgroup *hugetlb_cgroup_from_task(struct task_struct *task)
{
return hugetlb_cgroup_from_css(task_css(task, hugetlb_cgrp_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 hugetlb_cgroup *h_cg)
{
return hugetlb_cgroup_from_css(h_cg->css.parent);
}
static inline bool hugetlb_cgroup_have_usage(struct hugetlb_cgroup *h_cg)
{
int idx;
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_subsys_state *parent_css)
{
struct hugetlb_cgroup *parent_h_cgroup = hugetlb_cgroup_from_css(parent_css);
struct hugetlb_cgroup *h_cgroup;
int idx;
h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
if (!h_cgroup)
return ERR_PTR(-ENOMEM);
if (parent_h_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_subsys_state *css)
{
struct hugetlb_cgroup *h_cgroup;
h_cgroup = hugetlb_cgroup_from_css(css);
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 hugetlb_cgroup *h_cg,
struct page *page)
{
int csize;
struct res_counter *counter;
struct res_counter *fail_res;
struct hugetlb_cgroup *page_hcg;
struct hugetlb_cgroup *parent = parent_hugetlb_cgroup(h_cg);
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_subsys_state *css)
{
struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
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, h_cg, page);
spin_unlock(&hugetlb_lock);
idx++;
}
cond_resched();
} while (hugetlb_cgroup_have_usage(h_cg));
}
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_online(&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 u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css,
struct cftype *cft)
{
int idx, name;
struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
idx = MEMFILE_IDX(cft->private);
name = MEMFILE_ATTR(cft->private);
return res_counter_read_u64(&h_cg->hugepage[idx], name);
}
static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
int idx, name, ret;
unsigned long long val;
struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
buf = strstrip(buf);
idx = MEMFILE_IDX(of_cft(of)->private);
name = MEMFILE_ATTR(of_cft(of)->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(buf, &val);
if (ret)
break;
ret = res_counter_set_limit(&h_cg->hugepage[idx], val);
break;
default:
ret = -EINVAL;
break;
}
return ret ?: nbytes;
}
static ssize_t hugetlb_cgroup_reset(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
int idx, name, ret = 0;
struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
idx = MEMFILE_IDX(of_cft(of)->private);
name = MEMFILE_ATTR(of_cft(of)->private);
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 ?: nbytes;
}
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_u64 = hugetlb_cgroup_read_u64;
cft->write = 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_u64 = hugetlb_cgroup_read_u64;
/* 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->write = hugetlb_cgroup_reset;
cft->read_u64 = hugetlb_cgroup_read_u64;
/* 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->write = hugetlb_cgroup_reset;
cft->read_u64 = hugetlb_cgroup_read_u64;
/* NULL terminate the last cft */
cft = &h->cgroup_files[4];
memset(cft, 0, sizeof(*cft));
WARN_ON(cgroup_add_legacy_cftypes(&hugetlb_cgrp_subsys,
h->cgroup_files));
}
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_PAGE(!PageHuge(oldhpage), 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_cgrp_subsys = {
.css_alloc = hugetlb_cgroup_css_alloc,
.css_offline = hugetlb_cgroup_css_offline,
.css_free = hugetlb_cgroup_css_free,
};