mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-05 18:14:07 +08:00
0362f326d8
An exiting task might belong to an offline cgroup. In this case an
attempt to grab a cgroup reference from the task can end up with an
infinite loop in hugetlb_cgroup_charge_cgroup(), because neither the
cgroup will become online, neither the task will be migrated to a live
cgroup.
Fix this by switching over to css_tryget(). As css_tryget_online()
can't guarantee that the cgroup won't go offline, in most cases the
check doesn't make sense. In this particular case users of
hugetlb_cgroup_charge_cgroup() are not affected by this change.
A similar problem is described by commit 18fa84a2db
("cgroup: Use
css_tryget() instead of css_tryget_online() in task_get_css()").
Link: http://lkml.kernel.org/r/20191106225131.3543616-2-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
441 lines
11 KiB
C
441 lines
11 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/page_counter.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 page_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 (page_counter_read(&h_cg->hugepage[idx]))
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
static void hugetlb_cgroup_init(struct hugetlb_cgroup *h_cgroup,
|
|
struct hugetlb_cgroup *parent_h_cgroup)
|
|
{
|
|
int idx;
|
|
|
|
for (idx = 0; idx < HUGE_MAX_HSTATE; idx++) {
|
|
struct page_counter *counter = &h_cgroup->hugepage[idx];
|
|
struct page_counter *parent = NULL;
|
|
unsigned long limit;
|
|
int ret;
|
|
|
|
if (parent_h_cgroup)
|
|
parent = &parent_h_cgroup->hugepage[idx];
|
|
page_counter_init(counter, parent);
|
|
|
|
limit = round_down(PAGE_COUNTER_MAX,
|
|
1 << huge_page_order(&hstates[idx]));
|
|
ret = page_counter_set_max(counter, limit);
|
|
VM_BUG_ON(ret);
|
|
}
|
|
}
|
|
|
|
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;
|
|
|
|
h_cgroup = kzalloc(sizeof(*h_cgroup), GFP_KERNEL);
|
|
if (!h_cgroup)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
if (!parent_h_cgroup)
|
|
root_h_cgroup = h_cgroup;
|
|
|
|
hugetlb_cgroup_init(h_cgroup, parent_h_cgroup);
|
|
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)
|
|
{
|
|
unsigned int nr_pages;
|
|
struct page_counter *counter;
|
|
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;
|
|
|
|
nr_pages = compound_nr(page);
|
|
if (!parent) {
|
|
parent = root_h_cgroup;
|
|
/* root has no limit */
|
|
page_counter_charge(&parent->hugepage[idx], nr_pages);
|
|
}
|
|
counter = &h_cg->hugepage[idx];
|
|
/* Take the pages off the local counter */
|
|
page_counter_cancel(counter, nr_pages);
|
|
|
|
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 page_counter *counter;
|
|
struct hugetlb_cgroup *h_cg = NULL;
|
|
|
|
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();
|
|
|
|
if (!page_counter_try_charge(&h_cg->hugepage[idx], nr_pages, &counter))
|
|
ret = -ENOMEM;
|
|
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;
|
|
|
|
if (hugetlb_cgroup_disabled())
|
|
return;
|
|
lockdep_assert_held(&hugetlb_lock);
|
|
h_cg = hugetlb_cgroup_from_page(page);
|
|
if (unlikely(!h_cg))
|
|
return;
|
|
set_hugetlb_cgroup(page, NULL);
|
|
page_counter_uncharge(&h_cg->hugepage[idx], nr_pages);
|
|
return;
|
|
}
|
|
|
|
void hugetlb_cgroup_uncharge_cgroup(int idx, unsigned long nr_pages,
|
|
struct hugetlb_cgroup *h_cg)
|
|
{
|
|
if (hugetlb_cgroup_disabled() || !h_cg)
|
|
return;
|
|
|
|
if (huge_page_order(&hstates[idx]) < HUGETLB_CGROUP_MIN_ORDER)
|
|
return;
|
|
|
|
page_counter_uncharge(&h_cg->hugepage[idx], nr_pages);
|
|
return;
|
|
}
|
|
|
|
enum {
|
|
RES_USAGE,
|
|
RES_LIMIT,
|
|
RES_MAX_USAGE,
|
|
RES_FAILCNT,
|
|
};
|
|
|
|
static u64 hugetlb_cgroup_read_u64(struct cgroup_subsys_state *css,
|
|
struct cftype *cft)
|
|
{
|
|
struct page_counter *counter;
|
|
struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(css);
|
|
|
|
counter = &h_cg->hugepage[MEMFILE_IDX(cft->private)];
|
|
|
|
switch (MEMFILE_ATTR(cft->private)) {
|
|
case RES_USAGE:
|
|
return (u64)page_counter_read(counter) * PAGE_SIZE;
|
|
case RES_LIMIT:
|
|
return (u64)counter->max * PAGE_SIZE;
|
|
case RES_MAX_USAGE:
|
|
return (u64)counter->watermark * PAGE_SIZE;
|
|
case RES_FAILCNT:
|
|
return counter->failcnt;
|
|
default:
|
|
BUG();
|
|
}
|
|
}
|
|
|
|
static DEFINE_MUTEX(hugetlb_limit_mutex);
|
|
|
|
static ssize_t hugetlb_cgroup_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes, loff_t off)
|
|
{
|
|
int ret, idx;
|
|
unsigned long nr_pages;
|
|
struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
|
|
|
|
if (hugetlb_cgroup_is_root(h_cg)) /* Can't set limit on root */
|
|
return -EINVAL;
|
|
|
|
buf = strstrip(buf);
|
|
ret = page_counter_memparse(buf, "-1", &nr_pages);
|
|
if (ret)
|
|
return ret;
|
|
|
|
idx = MEMFILE_IDX(of_cft(of)->private);
|
|
nr_pages = round_down(nr_pages, 1 << huge_page_order(&hstates[idx]));
|
|
|
|
switch (MEMFILE_ATTR(of_cft(of)->private)) {
|
|
case RES_LIMIT:
|
|
mutex_lock(&hugetlb_limit_mutex);
|
|
ret = page_counter_set_max(&h_cg->hugepage[idx], nr_pages);
|
|
mutex_unlock(&hugetlb_limit_mutex);
|
|
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 ret = 0;
|
|
struct page_counter *counter;
|
|
struct hugetlb_cgroup *h_cg = hugetlb_cgroup_from_css(of_css(of));
|
|
|
|
counter = &h_cg->hugepage[MEMFILE_IDX(of_cft(of)->private)];
|
|
|
|
switch (MEMFILE_ATTR(of_cft(of)->private)) {
|
|
case RES_MAX_USAGE:
|
|
page_counter_reset_watermark(counter);
|
|
break;
|
|
case RES_FAILCNT:
|
|
counter->failcnt = 0;
|
|
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].private 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,
|
|
};
|