android_kernel_xiaomi_sm8350/mm/memcontrol.c
KAMEZAWA Hiroyuki 2ffebca6aa memcg: fix lru rotation in isolate_pages
Try to fix memcg's lru rotation sanity: make memcg use the same logic as
the global LRU does.

Now, at __isolate_lru_page() retruns -EBUSY, the page is rotated to the
tail of LRU in global LRU's isolate LRU pages.  But in memcg, it's not
handled.  This makes memcg do the same behavior as global LRU and rotate
LRU in the page is busy.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:03:48 -07:00

2629 lines
64 KiB
C

/* memcontrol.c - Memory Controller
*
* Copyright IBM Corporation, 2007
* Author Balbir Singh <balbir@linux.vnet.ibm.com>
*
* Copyright 2007 OpenVZ SWsoft Inc
* Author: Pavel Emelianov <xemul@openvz.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/res_counter.h>
#include <linux/memcontrol.h>
#include <linux/cgroup.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/smp.h>
#include <linux/page-flags.h>
#include <linux/backing-dev.h>
#include <linux/bit_spinlock.h>
#include <linux/rcupdate.h>
#include <linux/limits.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/vmalloc.h>
#include <linux/mm_inline.h>
#include <linux/page_cgroup.h>
#include "internal.h"
#include <asm/uaccess.h>
struct cgroup_subsys mem_cgroup_subsys __read_mostly;
#define MEM_CGROUP_RECLAIM_RETRIES 5
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
int do_swap_account __read_mostly;
static int really_do_swap_account __initdata = 1; /* for remember boot option*/
#else
#define do_swap_account (0)
#endif
static DEFINE_MUTEX(memcg_tasklist); /* can be hold under cgroup_mutex */
/*
* Statistics for memory cgroup.
*/
enum mem_cgroup_stat_index {
/*
* For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
*/
MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
MEM_CGROUP_STAT_MAPPED_FILE, /* # of pages charged as file rss */
MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
MEM_CGROUP_STAT_NSTATS,
};
struct mem_cgroup_stat_cpu {
s64 count[MEM_CGROUP_STAT_NSTATS];
} ____cacheline_aligned_in_smp;
struct mem_cgroup_stat {
struct mem_cgroup_stat_cpu cpustat[0];
};
/*
* For accounting under irq disable, no need for increment preempt count.
*/
static inline void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat_cpu *stat,
enum mem_cgroup_stat_index idx, int val)
{
stat->count[idx] += val;
}
static s64 mem_cgroup_read_stat(struct mem_cgroup_stat *stat,
enum mem_cgroup_stat_index idx)
{
int cpu;
s64 ret = 0;
for_each_possible_cpu(cpu)
ret += stat->cpustat[cpu].count[idx];
return ret;
}
static s64 mem_cgroup_local_usage(struct mem_cgroup_stat *stat)
{
s64 ret;
ret = mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_CACHE);
ret += mem_cgroup_read_stat(stat, MEM_CGROUP_STAT_RSS);
return ret;
}
/*
* per-zone information in memory controller.
*/
struct mem_cgroup_per_zone {
/*
* spin_lock to protect the per cgroup LRU
*/
struct list_head lists[NR_LRU_LISTS];
unsigned long count[NR_LRU_LISTS];
struct zone_reclaim_stat reclaim_stat;
};
/* Macro for accessing counter */
#define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
struct mem_cgroup_per_node {
struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
};
struct mem_cgroup_lru_info {
struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
};
/*
* The memory controller data structure. The memory controller controls both
* page cache and RSS per cgroup. We would eventually like to provide
* statistics based on the statistics developed by Rik Van Riel for clock-pro,
* to help the administrator determine what knobs to tune.
*
* TODO: Add a water mark for the memory controller. Reclaim will begin when
* we hit the water mark. May be even add a low water mark, such that
* no reclaim occurs from a cgroup at it's low water mark, this is
* a feature that will be implemented much later in the future.
*/
struct mem_cgroup {
struct cgroup_subsys_state css;
/*
* the counter to account for memory usage
*/
struct res_counter res;
/*
* the counter to account for mem+swap usage.
*/
struct res_counter memsw;
/*
* Per cgroup active and inactive list, similar to the
* per zone LRU lists.
*/
struct mem_cgroup_lru_info info;
/*
protect against reclaim related member.
*/
spinlock_t reclaim_param_lock;
int prev_priority; /* for recording reclaim priority */
/*
* While reclaiming in a hiearchy, we cache the last child we
* reclaimed from.
*/
int last_scanned_child;
/*
* Should the accounting and control be hierarchical, per subtree?
*/
bool use_hierarchy;
unsigned long last_oom_jiffies;
atomic_t refcnt;
unsigned int swappiness;
/* set when res.limit == memsw.limit */
bool memsw_is_minimum;
/*
* statistics. This must be placed at the end of memcg.
*/
struct mem_cgroup_stat stat;
};
enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
MEM_CGROUP_CHARGE_TYPE_MAPPED,
MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
NR_CHARGE_TYPE,
};
/* only for here (for easy reading.) */
#define PCGF_CACHE (1UL << PCG_CACHE)
#define PCGF_USED (1UL << PCG_USED)
#define PCGF_LOCK (1UL << PCG_LOCK)
static const unsigned long
pcg_default_flags[NR_CHARGE_TYPE] = {
PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* File Cache */
PCGF_USED | PCGF_LOCK, /* Anon */
PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
0, /* FORCE */
};
/* for encoding cft->private value on file */
#define _MEM (0)
#define _MEMSWAP (1)
#define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val))
#define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff)
#define MEMFILE_ATTR(val) ((val) & 0xffff)
static void mem_cgroup_get(struct mem_cgroup *mem);
static void mem_cgroup_put(struct mem_cgroup *mem);
static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem);
static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
struct page_cgroup *pc,
bool charge)
{
int val = (charge)? 1 : -1;
struct mem_cgroup_stat *stat = &mem->stat;
struct mem_cgroup_stat_cpu *cpustat;
int cpu = get_cpu();
cpustat = &stat->cpustat[cpu];
if (PageCgroupCache(pc))
__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
else
__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val);
if (charge)
__mem_cgroup_stat_add_safe(cpustat,
MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
else
__mem_cgroup_stat_add_safe(cpustat,
MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
put_cpu();
}
static struct mem_cgroup_per_zone *
mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
{
return &mem->info.nodeinfo[nid]->zoneinfo[zid];
}
static struct mem_cgroup_per_zone *
page_cgroup_zoneinfo(struct page_cgroup *pc)
{
struct mem_cgroup *mem = pc->mem_cgroup;
int nid = page_cgroup_nid(pc);
int zid = page_cgroup_zid(pc);
if (!mem)
return NULL;
return mem_cgroup_zoneinfo(mem, nid, zid);
}
static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem,
enum lru_list idx)
{
int nid, zid;
struct mem_cgroup_per_zone *mz;
u64 total = 0;
for_each_online_node(nid)
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
mz = mem_cgroup_zoneinfo(mem, nid, zid);
total += MEM_CGROUP_ZSTAT(mz, idx);
}
return total;
}
static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
{
return container_of(cgroup_subsys_state(cont,
mem_cgroup_subsys_id), struct mem_cgroup,
css);
}
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
{
/*
* mm_update_next_owner() may clear mm->owner to NULL
* if it races with swapoff, page migration, etc.
* So this can be called with p == NULL.
*/
if (unlikely(!p))
return NULL;
return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
struct mem_cgroup, css);
}
static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
{
struct mem_cgroup *mem = NULL;
if (!mm)
return NULL;
/*
* Because we have no locks, mm->owner's may be being moved to other
* cgroup. We use css_tryget() here even if this looks
* pessimistic (rather than adding locks here).
*/
rcu_read_lock();
do {
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (unlikely(!mem))
break;
} while (!css_tryget(&mem->css));
rcu_read_unlock();
return mem;
}
/*
* Call callback function against all cgroup under hierarchy tree.
*/
static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data,
int (*func)(struct mem_cgroup *, void *))
{
int found, ret, nextid;
struct cgroup_subsys_state *css;
struct mem_cgroup *mem;
if (!root->use_hierarchy)
return (*func)(root, data);
nextid = 1;
do {
ret = 0;
mem = NULL;
rcu_read_lock();
css = css_get_next(&mem_cgroup_subsys, nextid, &root->css,
&found);
if (css && css_tryget(css))
mem = container_of(css, struct mem_cgroup, css);
rcu_read_unlock();
if (mem) {
ret = (*func)(mem, data);
css_put(&mem->css);
}
nextid = found + 1;
} while (!ret && css);
return ret;
}
/*
* Following LRU functions are allowed to be used without PCG_LOCK.
* Operations are called by routine of global LRU independently from memcg.
* What we have to take care of here is validness of pc->mem_cgroup.
*
* Changes to pc->mem_cgroup happens when
* 1. charge
* 2. moving account
* In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
* It is added to LRU before charge.
* If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
* When moving account, the page is not on LRU. It's isolated.
*/
void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru)
{
struct page_cgroup *pc;
struct mem_cgroup *mem;
struct mem_cgroup_per_zone *mz;
if (mem_cgroup_disabled())
return;
pc = lookup_page_cgroup(page);
/* can happen while we handle swapcache. */
if (list_empty(&pc->lru) || !pc->mem_cgroup)
return;
/*
* We don't check PCG_USED bit. It's cleared when the "page" is finally
* removed from global LRU.
*/
mz = page_cgroup_zoneinfo(pc);
mem = pc->mem_cgroup;
MEM_CGROUP_ZSTAT(mz, lru) -= 1;
list_del_init(&pc->lru);
return;
}
void mem_cgroup_del_lru(struct page *page)
{
mem_cgroup_del_lru_list(page, page_lru(page));
}
void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru)
{
struct mem_cgroup_per_zone *mz;
struct page_cgroup *pc;
if (mem_cgroup_disabled())
return;
pc = lookup_page_cgroup(page);
/*
* Used bit is set without atomic ops but after smp_wmb().
* For making pc->mem_cgroup visible, insert smp_rmb() here.
*/
smp_rmb();
/* unused page is not rotated. */
if (!PageCgroupUsed(pc))
return;
mz = page_cgroup_zoneinfo(pc);
list_move(&pc->lru, &mz->lists[lru]);
}
void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru)
{
struct page_cgroup *pc;
struct mem_cgroup_per_zone *mz;
if (mem_cgroup_disabled())
return;
pc = lookup_page_cgroup(page);
/*
* Used bit is set without atomic ops but after smp_wmb().
* For making pc->mem_cgroup visible, insert smp_rmb() here.
*/
smp_rmb();
if (!PageCgroupUsed(pc))
return;
mz = page_cgroup_zoneinfo(pc);
MEM_CGROUP_ZSTAT(mz, lru) += 1;
list_add(&pc->lru, &mz->lists[lru]);
}
/*
* At handling SwapCache, pc->mem_cgroup may be changed while it's linked to
* lru because the page may.be reused after it's fully uncharged (because of
* SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge
* it again. This function is only used to charge SwapCache. It's done under
* lock_page and expected that zone->lru_lock is never held.
*/
static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page)
{
unsigned long flags;
struct zone *zone = page_zone(page);
struct page_cgroup *pc = lookup_page_cgroup(page);
spin_lock_irqsave(&zone->lru_lock, flags);
/*
* Forget old LRU when this page_cgroup is *not* used. This Used bit
* is guarded by lock_page() because the page is SwapCache.
*/
if (!PageCgroupUsed(pc))
mem_cgroup_del_lru_list(page, page_lru(page));
spin_unlock_irqrestore(&zone->lru_lock, flags);
}
static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page)
{
unsigned long flags;
struct zone *zone = page_zone(page);
struct page_cgroup *pc = lookup_page_cgroup(page);
spin_lock_irqsave(&zone->lru_lock, flags);
/* link when the page is linked to LRU but page_cgroup isn't */
if (PageLRU(page) && list_empty(&pc->lru))
mem_cgroup_add_lru_list(page, page_lru(page));
spin_unlock_irqrestore(&zone->lru_lock, flags);
}
void mem_cgroup_move_lists(struct page *page,
enum lru_list from, enum lru_list to)
{
if (mem_cgroup_disabled())
return;
mem_cgroup_del_lru_list(page, from);
mem_cgroup_add_lru_list(page, to);
}
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem)
{
int ret;
struct mem_cgroup *curr = NULL;
task_lock(task);
rcu_read_lock();
curr = try_get_mem_cgroup_from_mm(task->mm);
rcu_read_unlock();
task_unlock(task);
if (!curr)
return 0;
if (curr->use_hierarchy)
ret = css_is_ancestor(&curr->css, &mem->css);
else
ret = (curr == mem);
css_put(&curr->css);
return ret;
}
/*
* prev_priority control...this will be used in memory reclaim path.
*/
int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
{
int prev_priority;
spin_lock(&mem->reclaim_param_lock);
prev_priority = mem->prev_priority;
spin_unlock(&mem->reclaim_param_lock);
return prev_priority;
}
void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
{
spin_lock(&mem->reclaim_param_lock);
if (priority < mem->prev_priority)
mem->prev_priority = priority;
spin_unlock(&mem->reclaim_param_lock);
}
void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
{
spin_lock(&mem->reclaim_param_lock);
mem->prev_priority = priority;
spin_unlock(&mem->reclaim_param_lock);
}
static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
{
unsigned long active;
unsigned long inactive;
unsigned long gb;
unsigned long inactive_ratio;
inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON);
active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON);
gb = (inactive + active) >> (30 - PAGE_SHIFT);
if (gb)
inactive_ratio = int_sqrt(10 * gb);
else
inactive_ratio = 1;
if (present_pages) {
present_pages[0] = inactive;
present_pages[1] = active;
}
return inactive_ratio;
}
int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
{
unsigned long active;
unsigned long inactive;
unsigned long present_pages[2];
unsigned long inactive_ratio;
inactive_ratio = calc_inactive_ratio(memcg, present_pages);
inactive = present_pages[0];
active = present_pages[1];
if (inactive * inactive_ratio < active)
return 1;
return 0;
}
int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
{
unsigned long active;
unsigned long inactive;
inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE);
active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE);
return (active > inactive);
}
unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
struct zone *zone,
enum lru_list lru)
{
int nid = zone->zone_pgdat->node_id;
int zid = zone_idx(zone);
struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
return MEM_CGROUP_ZSTAT(mz, lru);
}
struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
struct zone *zone)
{
int nid = zone->zone_pgdat->node_id;
int zid = zone_idx(zone);
struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
return &mz->reclaim_stat;
}
struct zone_reclaim_stat *
mem_cgroup_get_reclaim_stat_from_page(struct page *page)
{
struct page_cgroup *pc;
struct mem_cgroup_per_zone *mz;
if (mem_cgroup_disabled())
return NULL;
pc = lookup_page_cgroup(page);
/*
* Used bit is set without atomic ops but after smp_wmb().
* For making pc->mem_cgroup visible, insert smp_rmb() here.
*/
smp_rmb();
if (!PageCgroupUsed(pc))
return NULL;
mz = page_cgroup_zoneinfo(pc);
if (!mz)
return NULL;
return &mz->reclaim_stat;
}
unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
struct list_head *dst,
unsigned long *scanned, int order,
int mode, struct zone *z,
struct mem_cgroup *mem_cont,
int active, int file)
{
unsigned long nr_taken = 0;
struct page *page;
unsigned long scan;
LIST_HEAD(pc_list);
struct list_head *src;
struct page_cgroup *pc, *tmp;
int nid = z->zone_pgdat->node_id;
int zid = zone_idx(z);
struct mem_cgroup_per_zone *mz;
int lru = LRU_FILE * !!file + !!active;
int ret;
BUG_ON(!mem_cont);
mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
src = &mz->lists[lru];
scan = 0;
list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
if (scan >= nr_to_scan)
break;
page = pc->page;
if (unlikely(!PageCgroupUsed(pc)))
continue;
if (unlikely(!PageLRU(page)))
continue;
scan++;
ret = __isolate_lru_page(page, mode, file);
switch (ret) {
case 0:
list_move(&page->lru, dst);
mem_cgroup_del_lru(page);
nr_taken++;
break;
case -EBUSY:
/* we don't affect global LRU but rotate in our LRU */
mem_cgroup_rotate_lru_list(page, page_lru(page));
break;
default:
break;
}
}
*scanned = scan;
return nr_taken;
}
#define mem_cgroup_from_res_counter(counter, member) \
container_of(counter, struct mem_cgroup, member)
static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem)
{
if (do_swap_account) {
if (res_counter_check_under_limit(&mem->res) &&
res_counter_check_under_limit(&mem->memsw))
return true;
} else
if (res_counter_check_under_limit(&mem->res))
return true;
return false;
}
static unsigned int get_swappiness(struct mem_cgroup *memcg)
{
struct cgroup *cgrp = memcg->css.cgroup;
unsigned int swappiness;
/* root ? */
if (cgrp->parent == NULL)
return vm_swappiness;
spin_lock(&memcg->reclaim_param_lock);
swappiness = memcg->swappiness;
spin_unlock(&memcg->reclaim_param_lock);
return swappiness;
}
static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
{
int *val = data;
(*val)++;
return 0;
}
/**
* mem_cgroup_print_mem_info: Called from OOM with tasklist_lock held in read mode.
* @memcg: The memory cgroup that went over limit
* @p: Task that is going to be killed
*
* NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
* enabled
*/
void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
{
struct cgroup *task_cgrp;
struct cgroup *mem_cgrp;
/*
* Need a buffer in BSS, can't rely on allocations. The code relies
* on the assumption that OOM is serialized for memory controller.
* If this assumption is broken, revisit this code.
*/
static char memcg_name[PATH_MAX];
int ret;
if (!memcg)
return;
rcu_read_lock();
mem_cgrp = memcg->css.cgroup;
task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
if (ret < 0) {
/*
* Unfortunately, we are unable to convert to a useful name
* But we'll still print out the usage information
*/
rcu_read_unlock();
goto done;
}
rcu_read_unlock();
printk(KERN_INFO "Task in %s killed", memcg_name);
rcu_read_lock();
ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
if (ret < 0) {
rcu_read_unlock();
goto done;
}
rcu_read_unlock();
/*
* Continues from above, so we don't need an KERN_ level
*/
printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
done:
printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
res_counter_read_u64(&memcg->res, RES_FAILCNT));
printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
"failcnt %llu\n",
res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
}
/*
* This function returns the number of memcg under hierarchy tree. Returns
* 1(self count) if no children.
*/
static int mem_cgroup_count_children(struct mem_cgroup *mem)
{
int num = 0;
mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb);
return num;
}
/*
* Visit the first child (need not be the first child as per the ordering
* of the cgroup list, since we track last_scanned_child) of @mem and use
* that to reclaim free pages from.
*/
static struct mem_cgroup *
mem_cgroup_select_victim(struct mem_cgroup *root_mem)
{
struct mem_cgroup *ret = NULL;
struct cgroup_subsys_state *css;
int nextid, found;
if (!root_mem->use_hierarchy) {
css_get(&root_mem->css);
ret = root_mem;
}
while (!ret) {
rcu_read_lock();
nextid = root_mem->last_scanned_child + 1;
css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css,
&found);
if (css && css_tryget(css))
ret = container_of(css, struct mem_cgroup, css);
rcu_read_unlock();
/* Updates scanning parameter */
spin_lock(&root_mem->reclaim_param_lock);
if (!css) {
/* this means start scan from ID:1 */
root_mem->last_scanned_child = 0;
} else
root_mem->last_scanned_child = found;
spin_unlock(&root_mem->reclaim_param_lock);
}
return ret;
}
/*
* Scan the hierarchy if needed to reclaim memory. We remember the last child
* we reclaimed from, so that we don't end up penalizing one child extensively
* based on its position in the children list.
*
* root_mem is the original ancestor that we've been reclaim from.
*
* We give up and return to the caller when we visit root_mem twice.
* (other groups can be removed while we're walking....)
*
* If shrink==true, for avoiding to free too much, this returns immedieately.
*/
static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
gfp_t gfp_mask, bool noswap, bool shrink)
{
struct mem_cgroup *victim;
int ret, total = 0;
int loop = 0;
/* If memsw_is_minimum==1, swap-out is of-no-use. */
if (root_mem->memsw_is_minimum)
noswap = true;
while (loop < 2) {
victim = mem_cgroup_select_victim(root_mem);
if (victim == root_mem)
loop++;
if (!mem_cgroup_local_usage(&victim->stat)) {
/* this cgroup's local usage == 0 */
css_put(&victim->css);
continue;
}
/* we use swappiness of local cgroup */
ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, noswap,
get_swappiness(victim));
css_put(&victim->css);
/*
* At shrinking usage, we can't check we should stop here or
* reclaim more. It's depends on callers. last_scanned_child
* will work enough for keeping fairness under tree.
*/
if (shrink)
return ret;
total += ret;
if (mem_cgroup_check_under_limit(root_mem))
return 1 + total;
}
return total;
}
bool mem_cgroup_oom_called(struct task_struct *task)
{
bool ret = false;
struct mem_cgroup *mem;
struct mm_struct *mm;
rcu_read_lock();
mm = task->mm;
if (!mm)
mm = &init_mm;
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (mem && time_before(jiffies, mem->last_oom_jiffies + HZ/10))
ret = true;
rcu_read_unlock();
return ret;
}
static int record_last_oom_cb(struct mem_cgroup *mem, void *data)
{
mem->last_oom_jiffies = jiffies;
return 0;
}
static void record_last_oom(struct mem_cgroup *mem)
{
mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb);
}
/*
* Currently used to update mapped file statistics, but the routine can be
* generalized to update other statistics as well.
*/
void mem_cgroup_update_mapped_file_stat(struct page *page, int val)
{
struct mem_cgroup *mem;
struct mem_cgroup_stat *stat;
struct mem_cgroup_stat_cpu *cpustat;
int cpu;
struct page_cgroup *pc;
if (!page_is_file_cache(page))
return;
pc = lookup_page_cgroup(page);
if (unlikely(!pc))
return;
lock_page_cgroup(pc);
mem = pc->mem_cgroup;
if (!mem)
goto done;
if (!PageCgroupUsed(pc))
goto done;
/*
* Preemption is already disabled, we don't need get_cpu()
*/
cpu = smp_processor_id();
stat = &mem->stat;
cpustat = &stat->cpustat[cpu];
__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE, val);
done:
unlock_page_cgroup(pc);
}
/*
* Unlike exported interface, "oom" parameter is added. if oom==true,
* oom-killer can be invoked.
*/
static int __mem_cgroup_try_charge(struct mm_struct *mm,
gfp_t gfp_mask, struct mem_cgroup **memcg,
bool oom)
{
struct mem_cgroup *mem, *mem_over_limit;
int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
struct res_counter *fail_res;
if (unlikely(test_thread_flag(TIF_MEMDIE))) {
/* Don't account this! */
*memcg = NULL;
return 0;
}
/*
* We always charge the cgroup the mm_struct belongs to.
* The mm_struct's mem_cgroup changes on task migration if the
* thread group leader migrates. It's possible that mm is not
* set, if so charge the init_mm (happens for pagecache usage).
*/
mem = *memcg;
if (likely(!mem)) {
mem = try_get_mem_cgroup_from_mm(mm);
*memcg = mem;
} else {
css_get(&mem->css);
}
if (unlikely(!mem))
return 0;
VM_BUG_ON(css_is_removed(&mem->css));
while (1) {
int ret;
bool noswap = false;
ret = res_counter_charge(&mem->res, PAGE_SIZE, &fail_res);
if (likely(!ret)) {
if (!do_swap_account)
break;
ret = res_counter_charge(&mem->memsw, PAGE_SIZE,
&fail_res);
if (likely(!ret))
break;
/* mem+swap counter fails */
res_counter_uncharge(&mem->res, PAGE_SIZE);
noswap = true;
mem_over_limit = mem_cgroup_from_res_counter(fail_res,
memsw);
} else
/* mem counter fails */
mem_over_limit = mem_cgroup_from_res_counter(fail_res,
res);
if (!(gfp_mask & __GFP_WAIT))
goto nomem;
ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, gfp_mask,
noswap, false);
if (ret)
continue;
/*
* try_to_free_mem_cgroup_pages() might not give us a full
* picture of reclaim. Some pages are reclaimed and might be
* moved to swap cache or just unmapped from the cgroup.
* Check the limit again to see if the reclaim reduced the
* current usage of the cgroup before giving up
*
*/
if (mem_cgroup_check_under_limit(mem_over_limit))
continue;
if (!nr_retries--) {
if (oom) {
mutex_lock(&memcg_tasklist);
mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
mutex_unlock(&memcg_tasklist);
record_last_oom(mem_over_limit);
}
goto nomem;
}
}
return 0;
nomem:
css_put(&mem->css);
return -ENOMEM;
}
/*
* A helper function to get mem_cgroup from ID. must be called under
* rcu_read_lock(). The caller must check css_is_removed() or some if
* it's concern. (dropping refcnt from swap can be called against removed
* memcg.)
*/
static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
{
struct cgroup_subsys_state *css;
/* ID 0 is unused ID */
if (!id)
return NULL;
css = css_lookup(&mem_cgroup_subsys, id);
if (!css)
return NULL;
return container_of(css, struct mem_cgroup, css);
}
static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
{
struct mem_cgroup *mem;
struct page_cgroup *pc;
unsigned short id;
swp_entry_t ent;
VM_BUG_ON(!PageLocked(page));
if (!PageSwapCache(page))
return NULL;
pc = lookup_page_cgroup(page);
lock_page_cgroup(pc);
if (PageCgroupUsed(pc)) {
mem = pc->mem_cgroup;
if (mem && !css_tryget(&mem->css))
mem = NULL;
} else {
ent.val = page_private(page);
id = lookup_swap_cgroup(ent);
rcu_read_lock();
mem = mem_cgroup_lookup(id);
if (mem && !css_tryget(&mem->css))
mem = NULL;
rcu_read_unlock();
}
unlock_page_cgroup(pc);
return mem;
}
/*
* commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be
* USED state. If already USED, uncharge and return.
*/
static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
struct page_cgroup *pc,
enum charge_type ctype)
{
/* try_charge() can return NULL to *memcg, taking care of it. */
if (!mem)
return;
lock_page_cgroup(pc);
if (unlikely(PageCgroupUsed(pc))) {
unlock_page_cgroup(pc);
res_counter_uncharge(&mem->res, PAGE_SIZE);
if (do_swap_account)
res_counter_uncharge(&mem->memsw, PAGE_SIZE);
css_put(&mem->css);
return;
}
pc->mem_cgroup = mem;
smp_wmb();
pc->flags = pcg_default_flags[ctype];
mem_cgroup_charge_statistics(mem, pc, true);
unlock_page_cgroup(pc);
}
/**
* mem_cgroup_move_account - move account of the page
* @pc: page_cgroup of the page.
* @from: mem_cgroup which the page is moved from.
* @to: mem_cgroup which the page is moved to. @from != @to.
*
* The caller must confirm following.
* - page is not on LRU (isolate_page() is useful.)
*
* returns 0 at success,
* returns -EBUSY when lock is busy or "pc" is unstable.
*
* This function does "uncharge" from old cgroup but doesn't do "charge" to
* new cgroup. It should be done by a caller.
*/
static int mem_cgroup_move_account(struct page_cgroup *pc,
struct mem_cgroup *from, struct mem_cgroup *to)
{
struct mem_cgroup_per_zone *from_mz, *to_mz;
int nid, zid;
int ret = -EBUSY;
struct page *page;
int cpu;
struct mem_cgroup_stat *stat;
struct mem_cgroup_stat_cpu *cpustat;
VM_BUG_ON(from == to);
VM_BUG_ON(PageLRU(pc->page));
nid = page_cgroup_nid(pc);
zid = page_cgroup_zid(pc);
from_mz = mem_cgroup_zoneinfo(from, nid, zid);
to_mz = mem_cgroup_zoneinfo(to, nid, zid);
if (!trylock_page_cgroup(pc))
return ret;
if (!PageCgroupUsed(pc))
goto out;
if (pc->mem_cgroup != from)
goto out;
res_counter_uncharge(&from->res, PAGE_SIZE);
mem_cgroup_charge_statistics(from, pc, false);
page = pc->page;
if (page_is_file_cache(page) && page_mapped(page)) {
cpu = smp_processor_id();
/* Update mapped_file data for mem_cgroup "from" */
stat = &from->stat;
cpustat = &stat->cpustat[cpu];
__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE,
-1);
/* Update mapped_file data for mem_cgroup "to" */
stat = &to->stat;
cpustat = &stat->cpustat[cpu];
__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE,
1);
}
if (do_swap_account)
res_counter_uncharge(&from->memsw, PAGE_SIZE);
css_put(&from->css);
css_get(&to->css);
pc->mem_cgroup = to;
mem_cgroup_charge_statistics(to, pc, true);
ret = 0;
out:
unlock_page_cgroup(pc);
return ret;
}
/*
* move charges to its parent.
*/
static int mem_cgroup_move_parent(struct page_cgroup *pc,
struct mem_cgroup *child,
gfp_t gfp_mask)
{
struct page *page = pc->page;
struct cgroup *cg = child->css.cgroup;
struct cgroup *pcg = cg->parent;
struct mem_cgroup *parent;
int ret;
/* Is ROOT ? */
if (!pcg)
return -EINVAL;
parent = mem_cgroup_from_cont(pcg);
ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false);
if (ret || !parent)
return ret;
if (!get_page_unless_zero(page)) {
ret = -EBUSY;
goto uncharge;
}
ret = isolate_lru_page(page);
if (ret)
goto cancel;
ret = mem_cgroup_move_account(pc, child, parent);
putback_lru_page(page);
if (!ret) {
put_page(page);
/* drop extra refcnt by try_charge() */
css_put(&parent->css);
return 0;
}
cancel:
put_page(page);
uncharge:
/* drop extra refcnt by try_charge() */
css_put(&parent->css);
/* uncharge if move fails */
res_counter_uncharge(&parent->res, PAGE_SIZE);
if (do_swap_account)
res_counter_uncharge(&parent->memsw, PAGE_SIZE);
return ret;
}
/*
* Charge the memory controller for page usage.
* Return
* 0 if the charge was successful
* < 0 if the cgroup is over its limit
*/
static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask, enum charge_type ctype,
struct mem_cgroup *memcg)
{
struct mem_cgroup *mem;
struct page_cgroup *pc;
int ret;
pc = lookup_page_cgroup(page);
/* can happen at boot */
if (unlikely(!pc))
return 0;
prefetchw(pc);
mem = memcg;
ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true);
if (ret || !mem)
return ret;
__mem_cgroup_commit_charge(mem, pc, ctype);
return 0;
}
int mem_cgroup_newpage_charge(struct page *page,
struct mm_struct *mm, gfp_t gfp_mask)
{
if (mem_cgroup_disabled())
return 0;
if (PageCompound(page))
return 0;
/*
* If already mapped, we don't have to account.
* If page cache, page->mapping has address_space.
* But page->mapping may have out-of-use anon_vma pointer,
* detecit it by PageAnon() check. newly-mapped-anon's page->mapping
* is NULL.
*/
if (page_mapped(page) || (page->mapping && !PageAnon(page)))
return 0;
if (unlikely(!mm))
mm = &init_mm;
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
}
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
enum charge_type ctype);
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
struct mem_cgroup *mem = NULL;
int ret;
if (mem_cgroup_disabled())
return 0;
if (PageCompound(page))
return 0;
/*
* Corner case handling. This is called from add_to_page_cache()
* in usual. But some FS (shmem) precharges this page before calling it
* and call add_to_page_cache() with GFP_NOWAIT.
*
* For GFP_NOWAIT case, the page may be pre-charged before calling
* add_to_page_cache(). (See shmem.c) check it here and avoid to call
* charge twice. (It works but has to pay a bit larger cost.)
* And when the page is SwapCache, it should take swap information
* into account. This is under lock_page() now.
*/
if (!(gfp_mask & __GFP_WAIT)) {
struct page_cgroup *pc;
pc = lookup_page_cgroup(page);
if (!pc)
return 0;
lock_page_cgroup(pc);
if (PageCgroupUsed(pc)) {
unlock_page_cgroup(pc);
return 0;
}
unlock_page_cgroup(pc);
}
if (unlikely(!mm && !mem))
mm = &init_mm;
if (page_is_file_cache(page))
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
/* shmem */
if (PageSwapCache(page)) {
ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
if (!ret)
__mem_cgroup_commit_charge_swapin(page, mem,
MEM_CGROUP_CHARGE_TYPE_SHMEM);
} else
ret = mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
return ret;
}
/*
* While swap-in, try_charge -> commit or cancel, the page is locked.
* And when try_charge() successfully returns, one refcnt to memcg without
* struct page_cgroup is aquired. This refcnt will be cumsumed by
* "commit()" or removed by "cancel()"
*/
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
struct page *page,
gfp_t mask, struct mem_cgroup **ptr)
{
struct mem_cgroup *mem;
int ret;
if (mem_cgroup_disabled())
return 0;
if (!do_swap_account)
goto charge_cur_mm;
/*
* A racing thread's fault, or swapoff, may have already updated
* the pte, and even removed page from swap cache: return success
* to go on to do_swap_page()'s pte_same() test, which should fail.
*/
if (!PageSwapCache(page))
return 0;
mem = try_get_mem_cgroup_from_swapcache(page);
if (!mem)
goto charge_cur_mm;
*ptr = mem;
ret = __mem_cgroup_try_charge(NULL, mask, ptr, true);
/* drop extra refcnt from tryget */
css_put(&mem->css);
return ret;
charge_cur_mm:
if (unlikely(!mm))
mm = &init_mm;
return __mem_cgroup_try_charge(mm, mask, ptr, true);
}
static void
__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
enum charge_type ctype)
{
struct page_cgroup *pc;
if (mem_cgroup_disabled())
return;
if (!ptr)
return;
pc = lookup_page_cgroup(page);
mem_cgroup_lru_del_before_commit_swapcache(page);
__mem_cgroup_commit_charge(ptr, pc, ctype);
mem_cgroup_lru_add_after_commit_swapcache(page);
/*
* Now swap is on-memory. This means this page may be
* counted both as mem and swap....double count.
* Fix it by uncharging from memsw. Basically, this SwapCache is stable
* under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
* may call delete_from_swap_cache() before reach here.
*/
if (do_swap_account && PageSwapCache(page)) {
swp_entry_t ent = {.val = page_private(page)};
unsigned short id;
struct mem_cgroup *memcg;
id = swap_cgroup_record(ent, 0);
rcu_read_lock();
memcg = mem_cgroup_lookup(id);
if (memcg) {
/*
* This recorded memcg can be obsolete one. So, avoid
* calling css_tryget
*/
res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
mem_cgroup_put(memcg);
}
rcu_read_unlock();
}
/* add this page(page_cgroup) to the LRU we want. */
}
void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
{
__mem_cgroup_commit_charge_swapin(page, ptr,
MEM_CGROUP_CHARGE_TYPE_MAPPED);
}
void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
{
if (mem_cgroup_disabled())
return;
if (!mem)
return;
res_counter_uncharge(&mem->res, PAGE_SIZE);
if (do_swap_account)
res_counter_uncharge(&mem->memsw, PAGE_SIZE);
css_put(&mem->css);
}
/*
* uncharge if !page_mapped(page)
*/
static struct mem_cgroup *
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
{
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
struct mem_cgroup_per_zone *mz;
if (mem_cgroup_disabled())
return NULL;
if (PageSwapCache(page))
return NULL;
/*
* Check if our page_cgroup is valid
*/
pc = lookup_page_cgroup(page);
if (unlikely(!pc || !PageCgroupUsed(pc)))
return NULL;
lock_page_cgroup(pc);
mem = pc->mem_cgroup;
if (!PageCgroupUsed(pc))
goto unlock_out;
switch (ctype) {
case MEM_CGROUP_CHARGE_TYPE_MAPPED:
case MEM_CGROUP_CHARGE_TYPE_DROP:
if (page_mapped(page))
goto unlock_out;
break;
case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
if (!PageAnon(page)) { /* Shared memory */
if (page->mapping && !page_is_file_cache(page))
goto unlock_out;
} else if (page_mapped(page)) /* Anon */
goto unlock_out;
break;
default:
break;
}
res_counter_uncharge(&mem->res, PAGE_SIZE);
if (do_swap_account && (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT))
res_counter_uncharge(&mem->memsw, PAGE_SIZE);
mem_cgroup_charge_statistics(mem, pc, false);
ClearPageCgroupUsed(pc);
/*
* pc->mem_cgroup is not cleared here. It will be accessed when it's
* freed from LRU. This is safe because uncharged page is expected not
* to be reused (freed soon). Exception is SwapCache, it's handled by
* special functions.
*/
mz = page_cgroup_zoneinfo(pc);
unlock_page_cgroup(pc);
/* at swapout, this memcg will be accessed to record to swap */
if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
css_put(&mem->css);
return mem;
unlock_out:
unlock_page_cgroup(pc);
return NULL;
}
void mem_cgroup_uncharge_page(struct page *page)
{
/* early check. */
if (page_mapped(page))
return;
if (page->mapping && !PageAnon(page))
return;
__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
}
void mem_cgroup_uncharge_cache_page(struct page *page)
{
VM_BUG_ON(page_mapped(page));
VM_BUG_ON(page->mapping);
__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}
#ifdef CONFIG_SWAP
/*
* called after __delete_from_swap_cache() and drop "page" account.
* memcg information is recorded to swap_cgroup of "ent"
*/
void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
{
struct mem_cgroup *memcg;
int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
if (!swapout) /* this was a swap cache but the swap is unused ! */
ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
memcg = __mem_cgroup_uncharge_common(page, ctype);
/* record memcg information */
if (do_swap_account && swapout && memcg) {
swap_cgroup_record(ent, css_id(&memcg->css));
mem_cgroup_get(memcg);
}
if (swapout && memcg)
css_put(&memcg->css);
}
#endif
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
/*
* called from swap_entry_free(). remove record in swap_cgroup and
* uncharge "memsw" account.
*/
void mem_cgroup_uncharge_swap(swp_entry_t ent)
{
struct mem_cgroup *memcg;
unsigned short id;
if (!do_swap_account)
return;
id = swap_cgroup_record(ent, 0);
rcu_read_lock();
memcg = mem_cgroup_lookup(id);
if (memcg) {
/*
* We uncharge this because swap is freed.
* This memcg can be obsolete one. We avoid calling css_tryget
*/
res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
mem_cgroup_put(memcg);
}
rcu_read_unlock();
}
#endif
/*
* Before starting migration, account PAGE_SIZE to mem_cgroup that the old
* page belongs to.
*/
int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
{
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
int ret = 0;
if (mem_cgroup_disabled())
return 0;
pc = lookup_page_cgroup(page);
lock_page_cgroup(pc);
if (PageCgroupUsed(pc)) {
mem = pc->mem_cgroup;
css_get(&mem->css);
}
unlock_page_cgroup(pc);
if (mem) {
ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
css_put(&mem->css);
}
*ptr = mem;
return ret;
}
/* remove redundant charge if migration failed*/
void mem_cgroup_end_migration(struct mem_cgroup *mem,
struct page *oldpage, struct page *newpage)
{
struct page *target, *unused;
struct page_cgroup *pc;
enum charge_type ctype;
if (!mem)
return;
/* at migration success, oldpage->mapping is NULL. */
if (oldpage->mapping) {
target = oldpage;
unused = NULL;
} else {
target = newpage;
unused = oldpage;
}
if (PageAnon(target))
ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
else if (page_is_file_cache(target))
ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
else
ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
/* unused page is not on radix-tree now. */
if (unused)
__mem_cgroup_uncharge_common(unused, ctype);
pc = lookup_page_cgroup(target);
/*
* __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
* So, double-counting is effectively avoided.
*/
__mem_cgroup_commit_charge(mem, pc, ctype);
/*
* Both of oldpage and newpage are still under lock_page().
* Then, we don't have to care about race in radix-tree.
* But we have to be careful that this page is unmapped or not.
*
* There is a case for !page_mapped(). At the start of
* migration, oldpage was mapped. But now, it's zapped.
* But we know *target* page is not freed/reused under us.
* mem_cgroup_uncharge_page() does all necessary checks.
*/
if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
mem_cgroup_uncharge_page(target);
}
/*
* A call to try to shrink memory usage on charge failure at shmem's swapin.
* Calling hierarchical_reclaim is not enough because we should update
* last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
* Moreover considering hierarchy, we should reclaim from the mem_over_limit,
* not from the memcg which this page would be charged to.
* try_charge_swapin does all of these works properly.
*/
int mem_cgroup_shmem_charge_fallback(struct page *page,
struct mm_struct *mm,
gfp_t gfp_mask)
{
struct mem_cgroup *mem = NULL;
int ret;
if (mem_cgroup_disabled())
return 0;
ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
if (!ret)
mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
return ret;
}
static DEFINE_MUTEX(set_limit_mutex);
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
unsigned long long val)
{
int retry_count;
int progress;
u64 memswlimit;
int ret = 0;
int children = mem_cgroup_count_children(memcg);
u64 curusage, oldusage;
/*
* For keeping hierarchical_reclaim simple, how long we should retry
* is depends on callers. We set our retry-count to be function
* of # of children which we should visit in this loop.
*/
retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
while (retry_count) {
if (signal_pending(current)) {
ret = -EINTR;
break;
}
/*
* Rather than hide all in some function, I do this in
* open coded manner. You see what this really does.
* We have to guarantee mem->res.limit < mem->memsw.limit.
*/
mutex_lock(&set_limit_mutex);
memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
if (memswlimit < val) {
ret = -EINVAL;
mutex_unlock(&set_limit_mutex);
break;
}
ret = res_counter_set_limit(&memcg->res, val);
if (!ret) {
if (memswlimit == val)
memcg->memsw_is_minimum = true;
else
memcg->memsw_is_minimum = false;
}
mutex_unlock(&set_limit_mutex);
if (!ret)
break;
progress = mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL,
false, true);
curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
else
oldusage = curusage;
}
return ret;
}
static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
unsigned long long val)
{
int retry_count;
u64 memlimit, oldusage, curusage;
int children = mem_cgroup_count_children(memcg);
int ret = -EBUSY;
/* see mem_cgroup_resize_res_limit */
retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
while (retry_count) {
if (signal_pending(current)) {
ret = -EINTR;
break;
}
/*
* Rather than hide all in some function, I do this in
* open coded manner. You see what this really does.
* We have to guarantee mem->res.limit < mem->memsw.limit.
*/
mutex_lock(&set_limit_mutex);
memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
if (memlimit > val) {
ret = -EINVAL;
mutex_unlock(&set_limit_mutex);
break;
}
ret = res_counter_set_limit(&memcg->memsw, val);
if (!ret) {
if (memlimit == val)
memcg->memsw_is_minimum = true;
else
memcg->memsw_is_minimum = false;
}
mutex_unlock(&set_limit_mutex);
if (!ret)
break;
mem_cgroup_hierarchical_reclaim(memcg, GFP_KERNEL, true, true);
curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
/* Usage is reduced ? */
if (curusage >= oldusage)
retry_count--;
else
oldusage = curusage;
}
return ret;
}
/*
* This routine traverse page_cgroup in given list and drop them all.
* *And* this routine doesn't reclaim page itself, just removes page_cgroup.
*/
static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
int node, int zid, enum lru_list lru)
{
struct zone *zone;
struct mem_cgroup_per_zone *mz;
struct page_cgroup *pc, *busy;
unsigned long flags, loop;
struct list_head *list;
int ret = 0;
zone = &NODE_DATA(node)->node_zones[zid];
mz = mem_cgroup_zoneinfo(mem, node, zid);
list = &mz->lists[lru];
loop = MEM_CGROUP_ZSTAT(mz, lru);
/* give some margin against EBUSY etc...*/
loop += 256;
busy = NULL;
while (loop--) {
ret = 0;
spin_lock_irqsave(&zone->lru_lock, flags);
if (list_empty(list)) {
spin_unlock_irqrestore(&zone->lru_lock, flags);
break;
}
pc = list_entry(list->prev, struct page_cgroup, lru);
if (busy == pc) {
list_move(&pc->lru, list);
busy = 0;
spin_unlock_irqrestore(&zone->lru_lock, flags);
continue;
}
spin_unlock_irqrestore(&zone->lru_lock, flags);
ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL);
if (ret == -ENOMEM)
break;
if (ret == -EBUSY || ret == -EINVAL) {
/* found lock contention or "pc" is obsolete. */
busy = pc;
cond_resched();
} else
busy = NULL;
}
if (!ret && !list_empty(list))
return -EBUSY;
return ret;
}
/*
* make mem_cgroup's charge to be 0 if there is no task.
* This enables deleting this mem_cgroup.
*/
static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
{
int ret;
int node, zid, shrink;
int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
struct cgroup *cgrp = mem->css.cgroup;
css_get(&mem->css);
shrink = 0;
/* should free all ? */
if (free_all)
goto try_to_free;
move_account:
while (mem->res.usage > 0) {
ret = -EBUSY;
if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
goto out;
ret = -EINTR;
if (signal_pending(current))
goto out;
/* This is for making all *used* pages to be on LRU. */
lru_add_drain_all();
ret = 0;
for_each_node_state(node, N_HIGH_MEMORY) {
for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
enum lru_list l;
for_each_lru(l) {
ret = mem_cgroup_force_empty_list(mem,
node, zid, l);
if (ret)
break;
}
}
if (ret)
break;
}
/* it seems parent cgroup doesn't have enough mem */
if (ret == -ENOMEM)
goto try_to_free;
cond_resched();
}
ret = 0;
out:
css_put(&mem->css);
return ret;
try_to_free:
/* returns EBUSY if there is a task or if we come here twice. */
if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
ret = -EBUSY;
goto out;
}
/* we call try-to-free pages for make this cgroup empty */
lru_add_drain_all();
/* try to free all pages in this cgroup */
shrink = 1;
while (nr_retries && mem->res.usage > 0) {
int progress;
if (signal_pending(current)) {
ret = -EINTR;
goto out;
}
progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
false, get_swappiness(mem));
if (!progress) {
nr_retries--;
/* maybe some writeback is necessary */
congestion_wait(WRITE, HZ/10);
}
}
lru_add_drain();
/* try move_account...there may be some *locked* pages. */
if (mem->res.usage)
goto move_account;
ret = 0;
goto out;
}
int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
{
return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
}
static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
{
return mem_cgroup_from_cont(cont)->use_hierarchy;
}
static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
u64 val)
{
int retval = 0;
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
struct cgroup *parent = cont->parent;
struct mem_cgroup *parent_mem = NULL;
if (parent)
parent_mem = mem_cgroup_from_cont(parent);
cgroup_lock();
/*
* If parent's use_hiearchy is set, we can't make any modifications
* in the child subtrees. If it is unset, then the change can
* occur, provided the current cgroup has no children.
*
* For the root cgroup, parent_mem is NULL, we allow value to be
* set if there are no children.
*/
if ((!parent_mem || !parent_mem->use_hierarchy) &&
(val == 1 || val == 0)) {
if (list_empty(&cont->children))
mem->use_hierarchy = val;
else
retval = -EBUSY;
} else
retval = -EINVAL;
cgroup_unlock();
return retval;
}
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
u64 val = 0;
int type, name;
type = MEMFILE_TYPE(cft->private);
name = MEMFILE_ATTR(cft->private);
switch (type) {
case _MEM:
val = res_counter_read_u64(&mem->res, name);
break;
case _MEMSWAP:
val = res_counter_read_u64(&mem->memsw, name);
break;
default:
BUG();
break;
}
return val;
}
/*
* The user of this function is...
* RES_LIMIT.
*/
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
const char *buffer)
{
struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
int type, name;
unsigned long long val;
int ret;
type = MEMFILE_TYPE(cft->private);
name = MEMFILE_ATTR(cft->private);
switch (name) {
case RES_LIMIT:
/* This function does all necessary parse...reuse it */
ret = res_counter_memparse_write_strategy(buffer, &val);
if (ret)
break;
if (type == _MEM)
ret = mem_cgroup_resize_limit(memcg, val);
else
ret = mem_cgroup_resize_memsw_limit(memcg, val);
break;
default:
ret = -EINVAL; /* should be BUG() ? */
break;
}
return ret;
}
static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
unsigned long long *mem_limit, unsigned long long *memsw_limit)
{
struct cgroup *cgroup;
unsigned long long min_limit, min_memsw_limit, tmp;
min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
cgroup = memcg->css.cgroup;
if (!memcg->use_hierarchy)
goto out;
while (cgroup->parent) {
cgroup = cgroup->parent;
memcg = mem_cgroup_from_cont(cgroup);
if (!memcg->use_hierarchy)
break;
tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
min_limit = min(min_limit, tmp);
tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
min_memsw_limit = min(min_memsw_limit, tmp);
}
out:
*mem_limit = min_limit;
*memsw_limit = min_memsw_limit;
return;
}
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
{
struct mem_cgroup *mem;
int type, name;
mem = mem_cgroup_from_cont(cont);
type = MEMFILE_TYPE(event);
name = MEMFILE_ATTR(event);
switch (name) {
case RES_MAX_USAGE:
if (type == _MEM)
res_counter_reset_max(&mem->res);
else
res_counter_reset_max(&mem->memsw);
break;
case RES_FAILCNT:
if (type == _MEM)
res_counter_reset_failcnt(&mem->res);
else
res_counter_reset_failcnt(&mem->memsw);
break;
}
return 0;
}
/* For read statistics */
enum {
MCS_CACHE,
MCS_RSS,
MCS_MAPPED_FILE,
MCS_PGPGIN,
MCS_PGPGOUT,
MCS_INACTIVE_ANON,
MCS_ACTIVE_ANON,
MCS_INACTIVE_FILE,
MCS_ACTIVE_FILE,
MCS_UNEVICTABLE,
NR_MCS_STAT,
};
struct mcs_total_stat {
s64 stat[NR_MCS_STAT];
};
struct {
char *local_name;
char *total_name;
} memcg_stat_strings[NR_MCS_STAT] = {
{"cache", "total_cache"},
{"rss", "total_rss"},
{"mapped_file", "total_mapped_file"},
{"pgpgin", "total_pgpgin"},
{"pgpgout", "total_pgpgout"},
{"inactive_anon", "total_inactive_anon"},
{"active_anon", "total_active_anon"},
{"inactive_file", "total_inactive_file"},
{"active_file", "total_active_file"},
{"unevictable", "total_unevictable"}
};
static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
{
struct mcs_total_stat *s = data;
s64 val;
/* per cpu stat */
val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_CACHE);
s->stat[MCS_CACHE] += val * PAGE_SIZE;
val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
s->stat[MCS_RSS] += val * PAGE_SIZE;
val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_MAPPED_FILE);
s->stat[MCS_MAPPED_FILE] += val * PAGE_SIZE;
val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGIN_COUNT);
s->stat[MCS_PGPGIN] += val;
val = mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_PGPGOUT_COUNT);
s->stat[MCS_PGPGOUT] += val;
/* per zone stat */
val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON);
s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE;
val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE);
s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE;
val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE);
s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE;
val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE);
s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE;
return 0;
}
static void
mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
{
mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat);
}
static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
struct cgroup_map_cb *cb)
{
struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont);
struct mcs_total_stat mystat;
int i;
memset(&mystat, 0, sizeof(mystat));
mem_cgroup_get_local_stat(mem_cont, &mystat);
for (i = 0; i < NR_MCS_STAT; i++)
cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]);
/* Hierarchical information */
{
unsigned long long limit, memsw_limit;
memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit);
cb->fill(cb, "hierarchical_memory_limit", limit);
if (do_swap_account)
cb->fill(cb, "hierarchical_memsw_limit", memsw_limit);
}
memset(&mystat, 0, sizeof(mystat));
mem_cgroup_get_total_stat(mem_cont, &mystat);
for (i = 0; i < NR_MCS_STAT; i++)
cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]);
#ifdef CONFIG_DEBUG_VM
cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
{
int nid, zid;
struct mem_cgroup_per_zone *mz;
unsigned long recent_rotated[2] = {0, 0};
unsigned long recent_scanned[2] = {0, 0};
for_each_online_node(nid)
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
recent_rotated[0] +=
mz->reclaim_stat.recent_rotated[0];
recent_rotated[1] +=
mz->reclaim_stat.recent_rotated[1];
recent_scanned[0] +=
mz->reclaim_stat.recent_scanned[0];
recent_scanned[1] +=
mz->reclaim_stat.recent_scanned[1];
}
cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
cb->fill(cb, "recent_scanned_anon", recent_scanned[0]);
cb->fill(cb, "recent_scanned_file", recent_scanned[1]);
}
#endif
return 0;
}
static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
return get_swappiness(memcg);
}
static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
u64 val)
{
struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
struct mem_cgroup *parent;
if (val > 100)
return -EINVAL;
if (cgrp->parent == NULL)
return -EINVAL;
parent = mem_cgroup_from_cont(cgrp->parent);
cgroup_lock();
/* If under hierarchy, only empty-root can set this value */
if ((parent->use_hierarchy) ||
(memcg->use_hierarchy && !list_empty(&cgrp->children))) {
cgroup_unlock();
return -EINVAL;
}
spin_lock(&memcg->reclaim_param_lock);
memcg->swappiness = val;
spin_unlock(&memcg->reclaim_param_lock);
cgroup_unlock();
return 0;
}
static struct cftype mem_cgroup_files[] = {
{
.name = "usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
.read_u64 = mem_cgroup_read,
},
{
.name = "max_usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
.trigger = mem_cgroup_reset,
.read_u64 = mem_cgroup_read,
},
{
.name = "limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
.write_string = mem_cgroup_write,
.read_u64 = mem_cgroup_read,
},
{
.name = "failcnt",
.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
.trigger = mem_cgroup_reset,
.read_u64 = mem_cgroup_read,
},
{
.name = "stat",
.read_map = mem_control_stat_show,
},
{
.name = "force_empty",
.trigger = mem_cgroup_force_empty_write,
},
{
.name = "use_hierarchy",
.write_u64 = mem_cgroup_hierarchy_write,
.read_u64 = mem_cgroup_hierarchy_read,
},
{
.name = "swappiness",
.read_u64 = mem_cgroup_swappiness_read,
.write_u64 = mem_cgroup_swappiness_write,
},
};
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static struct cftype memsw_cgroup_files[] = {
{
.name = "memsw.usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
.read_u64 = mem_cgroup_read,
},
{
.name = "memsw.max_usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
.trigger = mem_cgroup_reset,
.read_u64 = mem_cgroup_read,
},
{
.name = "memsw.limit_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
.write_string = mem_cgroup_write,
.read_u64 = mem_cgroup_read,
},
{
.name = "memsw.failcnt",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
.trigger = mem_cgroup_reset,
.read_u64 = mem_cgroup_read,
},
};
static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
{
if (!do_swap_account)
return 0;
return cgroup_add_files(cont, ss, memsw_cgroup_files,
ARRAY_SIZE(memsw_cgroup_files));
};
#else
static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss)
{
return 0;
}
#endif
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
struct mem_cgroup_per_node *pn;
struct mem_cgroup_per_zone *mz;
enum lru_list l;
int zone, tmp = node;
/*
* This routine is called against possible nodes.
* But it's BUG to call kmalloc() against offline node.
*
* TODO: this routine can waste much memory for nodes which will
* never be onlined. It's better to use memory hotplug callback
* function.
*/
if (!node_state(node, N_NORMAL_MEMORY))
tmp = -1;
pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
if (!pn)
return 1;
mem->info.nodeinfo[node] = pn;
memset(pn, 0, sizeof(*pn));
for (zone = 0; zone < MAX_NR_ZONES; zone++) {
mz = &pn->zoneinfo[zone];
for_each_lru(l)
INIT_LIST_HEAD(&mz->lists[l]);
}
return 0;
}
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
kfree(mem->info.nodeinfo[node]);
}
static int mem_cgroup_size(void)
{
int cpustat_size = nr_cpu_ids * sizeof(struct mem_cgroup_stat_cpu);
return sizeof(struct mem_cgroup) + cpustat_size;
}
static struct mem_cgroup *mem_cgroup_alloc(void)
{
struct mem_cgroup *mem;
int size = mem_cgroup_size();
if (size < PAGE_SIZE)
mem = kmalloc(size, GFP_KERNEL);
else
mem = vmalloc(size);
if (mem)
memset(mem, 0, size);
return mem;
}
/*
* At destroying mem_cgroup, references from swap_cgroup can remain.
* (scanning all at force_empty is too costly...)
*
* Instead of clearing all references at force_empty, we remember
* the number of reference from swap_cgroup and free mem_cgroup when
* it goes down to 0.
*
* Removal of cgroup itself succeeds regardless of refs from swap.
*/
static void __mem_cgroup_free(struct mem_cgroup *mem)
{
int node;
free_css_id(&mem_cgroup_subsys, &mem->css);
for_each_node_state(node, N_POSSIBLE)
free_mem_cgroup_per_zone_info(mem, node);
if (mem_cgroup_size() < PAGE_SIZE)
kfree(mem);
else
vfree(mem);
}
static void mem_cgroup_get(struct mem_cgroup *mem)
{
atomic_inc(&mem->refcnt);
}
static void mem_cgroup_put(struct mem_cgroup *mem)
{
if (atomic_dec_and_test(&mem->refcnt)) {
struct mem_cgroup *parent = parent_mem_cgroup(mem);
__mem_cgroup_free(mem);
if (parent)
mem_cgroup_put(parent);
}
}
/*
* Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
*/
static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem)
{
if (!mem->res.parent)
return NULL;
return mem_cgroup_from_res_counter(mem->res.parent, res);
}
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
if (!mem_cgroup_disabled() && really_do_swap_account)
do_swap_account = 1;
}
#else
static void __init enable_swap_cgroup(void)
{
}
#endif
static struct cgroup_subsys_state * __ref
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
struct mem_cgroup *mem, *parent;
long error = -ENOMEM;
int node;
mem = mem_cgroup_alloc();
if (!mem)
return ERR_PTR(error);
for_each_node_state(node, N_POSSIBLE)
if (alloc_mem_cgroup_per_zone_info(mem, node))
goto free_out;
/* root ? */
if (cont->parent == NULL) {
enable_swap_cgroup();
parent = NULL;
} else {
parent = mem_cgroup_from_cont(cont->parent);
mem->use_hierarchy = parent->use_hierarchy;
}
if (parent && parent->use_hierarchy) {
res_counter_init(&mem->res, &parent->res);
res_counter_init(&mem->memsw, &parent->memsw);
/*
* We increment refcnt of the parent to ensure that we can
* safely access it on res_counter_charge/uncharge.
* This refcnt will be decremented when freeing this
* mem_cgroup(see mem_cgroup_put).
*/
mem_cgroup_get(parent);
} else {
res_counter_init(&mem->res, NULL);
res_counter_init(&mem->memsw, NULL);
}
mem->last_scanned_child = 0;
spin_lock_init(&mem->reclaim_param_lock);
if (parent)
mem->swappiness = get_swappiness(parent);
atomic_set(&mem->refcnt, 1);
return &mem->css;
free_out:
__mem_cgroup_free(mem);
return ERR_PTR(error);
}
static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
struct cgroup *cont)
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
return mem_cgroup_force_empty(mem, false);
}
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
struct cgroup *cont)
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
mem_cgroup_put(mem);
}
static int mem_cgroup_populate(struct cgroup_subsys *ss,
struct cgroup *cont)
{
int ret;
ret = cgroup_add_files(cont, ss, mem_cgroup_files,
ARRAY_SIZE(mem_cgroup_files));
if (!ret)
ret = register_memsw_files(cont, ss);
return ret;
}
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
struct cgroup *cont,
struct cgroup *old_cont,
struct task_struct *p)
{
mutex_lock(&memcg_tasklist);
/*
* FIXME: It's better to move charges of this process from old
* memcg to new memcg. But it's just on TODO-List now.
*/
mutex_unlock(&memcg_tasklist);
}
struct cgroup_subsys mem_cgroup_subsys = {
.name = "memory",
.subsys_id = mem_cgroup_subsys_id,
.create = mem_cgroup_create,
.pre_destroy = mem_cgroup_pre_destroy,
.destroy = mem_cgroup_destroy,
.populate = mem_cgroup_populate,
.attach = mem_cgroup_move_task,
.early_init = 0,
.use_id = 1,
};
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static int __init disable_swap_account(char *s)
{
really_do_swap_account = 0;
return 1;
}
__setup("noswapaccount", disable_swap_account);
#endif