linux/mm/memcontrol.c
KOSAKI Motohiro 2733c06ac8 memcg: protect prev_priority
Currently, mem_cgroup doesn't have own lock and almost its member doesn't
need.  (e.g.  mem_cgroup->info is protected by zone lock, mem_cgroup->stat
is per cpu variable)

However, there is one explict exception.  mem_cgroup->prev_priorit need
lock, but doesn't protect.  Luckly, this is NOT bug because prev_priority
isn't used for current reclaim code.

However, we plan to use prev_priority future again.  Therefore, fixing is
better.

In addition, we plan to reuse this lock for another member.  Then
"reclaim_param_lock" name is better than "prev_priority_lock".

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:08 -08:00

2162 lines
52 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/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 = 0 */
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
/*
* 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 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;
}
/*
* 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. Protected by cgroup_lock()
*/
struct mem_cgroup *last_scanned_child;
/*
* Should the accounting and control be hierarchical, per subtree?
*/
bool use_hierarchy;
unsigned long last_oom_jiffies;
int obsolete;
atomic_t refcnt;
unsigned int inactive_ratio;
/*
* 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 */
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 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_all_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);
}
/*
* 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))
return;
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);
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);
/* barrier to sync with "charge" */
smp_rmb();
if (!PageCgroupUsed(pc))
return;
mz = page_cgroup_zoneinfo(pc);
MEM_CGROUP_ZSTAT(mz, lru) += 1;
list_add(&pc->lru, &mz->lists[lru]);
}
/*
* To add swapcache into LRU. Be careful to all this function.
* zone->lru_lock shouldn't be held and irq must not be disabled.
*/
static void mem_cgroup_lru_fixup(struct page *page)
{
if (!isolate_lru_page(page))
putback_lru_page(page);
}
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;
task_lock(task);
ret = task->mm && mm_match_cgroup(task->mm, mem);
task_unlock(task);
return ret;
}
/*
* Calculate mapped_ratio under memory controller. This will be used in
* vmscan.c for deteremining we have to reclaim mapped pages.
*/
int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem)
{
long total, rss;
/*
* usage is recorded in bytes. But, here, we assume the number of
* physical pages can be represented by "long" on any arch.
*/
total = (long) (mem->res.usage >> PAGE_SHIFT) + 1L;
rss = (long)mem_cgroup_read_stat(&mem->stat, MEM_CGROUP_STAT_RSS);
return (int)((rss * 100L) / total);
}
/*
* 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);
}
int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)
{
unsigned long active;
unsigned long inactive;
inactive = mem_cgroup_get_all_zonestat(memcg, LRU_INACTIVE_ANON);
active = mem_cgroup_get_all_zonestat(memcg, LRU_ACTIVE_ANON);
if (inactive * memcg->inactive_ratio < active)
return 1;
return 0;
}
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);
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;
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++;
if (__isolate_lru_page(page, mode, file) == 0) {
list_move(&page->lru, dst);
nr_taken++;
}
}
*scanned = scan;
return nr_taken;
}
#define mem_cgroup_from_res_counter(counter, member) \
container_of(counter, struct mem_cgroup, member)
/*
* This routine finds the DFS walk successor. This routine should be
* called with cgroup_mutex held
*/
static struct mem_cgroup *
mem_cgroup_get_next_node(struct mem_cgroup *curr, struct mem_cgroup *root_mem)
{
struct cgroup *cgroup, *curr_cgroup, *root_cgroup;
curr_cgroup = curr->css.cgroup;
root_cgroup = root_mem->css.cgroup;
if (!list_empty(&curr_cgroup->children)) {
/*
* Walk down to children
*/
mem_cgroup_put(curr);
cgroup = list_entry(curr_cgroup->children.next,
struct cgroup, sibling);
curr = mem_cgroup_from_cont(cgroup);
mem_cgroup_get(curr);
goto done;
}
visit_parent:
if (curr_cgroup == root_cgroup) {
mem_cgroup_put(curr);
curr = root_mem;
mem_cgroup_get(curr);
goto done;
}
/*
* Goto next sibling
*/
if (curr_cgroup->sibling.next != &curr_cgroup->parent->children) {
mem_cgroup_put(curr);
cgroup = list_entry(curr_cgroup->sibling.next, struct cgroup,
sibling);
curr = mem_cgroup_from_cont(cgroup);
mem_cgroup_get(curr);
goto done;
}
/*
* Go up to next parent and next parent's sibling if need be
*/
curr_cgroup = curr_cgroup->parent;
goto visit_parent;
done:
root_mem->last_scanned_child = curr;
return curr;
}
/*
* 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_get_first_node(struct mem_cgroup *root_mem)
{
struct cgroup *cgroup;
struct mem_cgroup *ret;
bool obsolete = (root_mem->last_scanned_child &&
root_mem->last_scanned_child->obsolete);
/*
* Scan all children under the mem_cgroup mem
*/
cgroup_lock();
if (list_empty(&root_mem->css.cgroup->children)) {
ret = root_mem;
goto done;
}
if (!root_mem->last_scanned_child || obsolete) {
if (obsolete)
mem_cgroup_put(root_mem->last_scanned_child);
cgroup = list_first_entry(&root_mem->css.cgroup->children,
struct cgroup, sibling);
ret = mem_cgroup_from_cont(cgroup);
mem_cgroup_get(ret);
} else
ret = mem_cgroup_get_next_node(root_mem->last_scanned_child,
root_mem);
done:
root_mem->last_scanned_child = ret;
cgroup_unlock();
return ret;
}
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;
}
/*
* Dance down 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.
*/
static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
gfp_t gfp_mask, bool noswap)
{
struct mem_cgroup *next_mem;
int ret = 0;
/*
* Reclaim unconditionally and don't check for return value.
* We need to reclaim in the current group and down the tree.
* One might think about checking for children before reclaiming,
* but there might be left over accounting, even after children
* have left.
*/
ret = try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap);
if (mem_cgroup_check_under_limit(root_mem))
return 0;
if (!root_mem->use_hierarchy)
return ret;
next_mem = mem_cgroup_get_first_node(root_mem);
while (next_mem != root_mem) {
if (next_mem->obsolete) {
mem_cgroup_put(next_mem);
cgroup_lock();
next_mem = mem_cgroup_get_first_node(root_mem);
cgroup_unlock();
continue;
}
ret = try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap);
if (mem_cgroup_check_under_limit(root_mem))
return 0;
cgroup_lock();
next_mem = mem_cgroup_get_next_node(next_mem, root_mem);
cgroup_unlock();
}
return ret;
}
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;
}
/*
* 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).
*/
if (likely(!*memcg)) {
rcu_read_lock();
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (unlikely(!mem)) {
rcu_read_unlock();
return 0;
}
/*
* For every charge from the cgroup, increment reference count
*/
css_get(&mem->css);
*memcg = mem;
rcu_read_unlock();
} else {
mem = *memcg;
css_get(&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);
/*
* 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) {
mem_cgroup_out_of_memory(mem_over_limit, gfp_mask);
mem_over_limit->last_oom_jiffies = jiffies;
}
goto nomem;
}
}
return 0;
nomem:
css_put(&mem->css);
return -ENOMEM;
}
/**
* mem_cgroup_try_charge - get charge of PAGE_SIZE.
* @mm: an mm_struct which is charged against. (when *memcg is NULL)
* @gfp_mask: gfp_mask for reclaim.
* @memcg: a pointer to memory cgroup which is charged against.
*
* charge against memory cgroup pointed by *memcg. if *memcg == NULL, estimated
* memory cgroup from @mm is got and stored in *memcg.
*
* Returns 0 if success. -ENOMEM at failure.
* This call can invoke OOM-Killer.
*/
int mem_cgroup_try_charge(struct mm_struct *mm,
gfp_t mask, struct mem_cgroup **memcg)
{
return __mem_cgroup_try_charge(mm, mask, memcg, true);
}
/*
* 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;
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;
css_put(&from->css);
res_counter_uncharge(&from->res, PAGE_SIZE);
mem_cgroup_charge_statistics(from, pc, false);
if (do_swap_account)
res_counter_uncharge(&from->memsw, PAGE_SIZE);
pc->mem_cgroup = to;
mem_cgroup_charge_statistics(to, pc, true);
css_get(&to->css);
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))
return -EBUSY;
ret = isolate_lru_page(page);
if (ret)
goto cancel;
ret = mem_cgroup_move_account(pc, child, parent);
/* drop extra refcnt by try_charge() (move_account increment one) */
css_put(&parent->css);
putback_lru_page(page);
if (!ret) {
put_page(page);
return 0;
}
/* uncharge if move fails */
cancel:
res_counter_uncharge(&parent->res, PAGE_SIZE);
if (do_swap_account)
res_counter_uncharge(&parent->memsw, PAGE_SIZE);
put_page(page);
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);
}
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
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.)
*/
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))
mm = &init_mm;
if (page_is_file_cache(page))
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
else
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL);
}
int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
struct page *page,
gfp_t mask, struct mem_cgroup **ptr)
{
struct mem_cgroup *mem;
swp_entry_t ent;
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;
ent.val = page_private(page);
mem = lookup_swap_cgroup(ent);
if (!mem || mem->obsolete)
goto charge_cur_mm;
*ptr = mem;
return __mem_cgroup_try_charge(NULL, mask, ptr, true);
charge_cur_mm:
if (unlikely(!mm))
mm = &init_mm;
return __mem_cgroup_try_charge(mm, mask, ptr, true);
}
#ifdef CONFIG_SWAP
int mem_cgroup_cache_charge_swapin(struct page *page,
struct mm_struct *mm, gfp_t mask, bool locked)
{
int ret = 0;
if (mem_cgroup_disabled())
return 0;
if (unlikely(!mm))
mm = &init_mm;
if (!locked)
lock_page(page);
/*
* If not locked, the page can be dropped from SwapCache until
* we reach here.
*/
if (PageSwapCache(page)) {
struct mem_cgroup *mem = NULL;
swp_entry_t ent;
ent.val = page_private(page);
if (do_swap_account) {
mem = lookup_swap_cgroup(ent);
if (mem && mem->obsolete)
mem = NULL;
if (mem)
mm = NULL;
}
ret = mem_cgroup_charge_common(page, mm, mask,
MEM_CGROUP_CHARGE_TYPE_SHMEM, mem);
if (!ret && do_swap_account) {
/* avoid double counting */
mem = swap_cgroup_record(ent, NULL);
if (mem) {
res_counter_uncharge(&mem->memsw, PAGE_SIZE);
mem_cgroup_put(mem);
}
}
}
if (!locked)
unlock_page(page);
/* add this page(page_cgroup) to the LRU we want. */
mem_cgroup_lru_fixup(page);
return ret;
}
#endif
void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
{
struct page_cgroup *pc;
if (mem_cgroup_disabled())
return;
if (!ptr)
return;
pc = lookup_page_cgroup(page);
__mem_cgroup_commit_charge(ptr, pc, MEM_CGROUP_CHARGE_TYPE_MAPPED);
/*
* 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. This SwapCache is stable
* because we're still under lock_page().
*/
if (do_swap_account) {
swp_entry_t ent = {.val = page_private(page)};
struct mem_cgroup *memcg;
memcg = swap_cgroup_record(ent, NULL);
if (memcg) {
/* If memcg is obsolete, memcg can be != ptr */
res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
mem_cgroup_put(memcg);
}
}
/* add this page(page_cgroup) to the LRU we want. */
mem_cgroup_lru_fixup(page);
}
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:
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);
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);
}
/*
* called from __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)
{
struct mem_cgroup *memcg;
memcg = __mem_cgroup_uncharge_common(page,
MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
/* record memcg information */
if (do_swap_account && memcg) {
swap_cgroup_record(ent, memcg);
mem_cgroup_get(memcg);
}
if (memcg)
css_put(&memcg->css);
}
#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;
if (!do_swap_account)
return;
memcg = swap_cgroup_record(ent, NULL);
if (memcg) {
res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
mem_cgroup_put(memcg);
}
}
#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);
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 under specified resource controller.
* This is typically used for page reclaiming for shmem for reducing side
* effect of page allocation from shmem, which is used by some mem_cgroup.
*/
int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
{
struct mem_cgroup *mem;
int progress = 0;
int retry = MEM_CGROUP_RECLAIM_RETRIES;
if (mem_cgroup_disabled())
return 0;
if (!mm)
return 0;
rcu_read_lock();
mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (unlikely(!mem)) {
rcu_read_unlock();
return 0;
}
css_get(&mem->css);
rcu_read_unlock();
do {
progress = try_to_free_mem_cgroup_pages(mem, gfp_mask, true);
progress += mem_cgroup_check_under_limit(mem);
} while (!progress && --retry);
css_put(&mem->css);
if (!retry)
return -ENOMEM;
return 0;
}
/*
* The inactive anon list should be small enough that the VM never has to
* do too much work, but large enough that each inactive page has a chance
* to be referenced again before it is swapped out.
*
* this calculation is straightforward porting from
* page_alloc.c::setup_per_zone_inactive_ratio().
* it describe more detail.
*/
static void mem_cgroup_set_inactive_ratio(struct mem_cgroup *memcg)
{
unsigned int gb, ratio;
gb = res_counter_read_u64(&memcg->res, RES_LIMIT) >> 30;
if (gb)
ratio = int_sqrt(10 * gb);
else
ratio = 1;
memcg->inactive_ratio = ratio;
}
static DEFINE_MUTEX(set_limit_mutex);
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
unsigned long long val)
{
int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
int progress;
u64 memswlimit;
int ret = 0;
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);
mutex_unlock(&set_limit_mutex);
if (!ret)
break;
progress = try_to_free_mem_cgroup_pages(memcg,
GFP_KERNEL, false);
if (!progress) retry_count--;
}
if (!ret)
mem_cgroup_set_inactive_ratio(memcg);
return ret;
}
int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
unsigned long long val)
{
int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
u64 memlimit, oldusage, curusage;
int ret;
if (!do_swap_account)
return -EINVAL;
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);
mutex_unlock(&set_limit_mutex);
if (!ret)
break;
oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL, true);
curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
if (curusage >= oldusage)
retry_count--;
}
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_POSSIBLE) {
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);
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:
if (do_swap_account)
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 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;
}
static const struct mem_cgroup_stat_desc {
const char *msg;
u64 unit;
} mem_cgroup_stat_desc[] = {
[MEM_CGROUP_STAT_CACHE] = { "cache", PAGE_SIZE, },
[MEM_CGROUP_STAT_RSS] = { "rss", PAGE_SIZE, },
[MEM_CGROUP_STAT_PGPGIN_COUNT] = {"pgpgin", 1, },
[MEM_CGROUP_STAT_PGPGOUT_COUNT] = {"pgpgout", 1, },
};
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 mem_cgroup_stat *stat = &mem_cont->stat;
int i;
for (i = 0; i < ARRAY_SIZE(stat->cpustat[0].count); i++) {
s64 val;
val = mem_cgroup_read_stat(stat, i);
val *= mem_cgroup_stat_desc[i].unit;
cb->fill(cb, mem_cgroup_stat_desc[i].msg, val);
}
/* showing # of active pages */
{
unsigned long active_anon, inactive_anon;
unsigned long active_file, inactive_file;
unsigned long unevictable;
inactive_anon = mem_cgroup_get_all_zonestat(mem_cont,
LRU_INACTIVE_ANON);
active_anon = mem_cgroup_get_all_zonestat(mem_cont,
LRU_ACTIVE_ANON);
inactive_file = mem_cgroup_get_all_zonestat(mem_cont,
LRU_INACTIVE_FILE);
active_file = mem_cgroup_get_all_zonestat(mem_cont,
LRU_ACTIVE_FILE);
unevictable = mem_cgroup_get_all_zonestat(mem_cont,
LRU_UNEVICTABLE);
cb->fill(cb, "active_anon", (active_anon) * PAGE_SIZE);
cb->fill(cb, "inactive_anon", (inactive_anon) * PAGE_SIZE);
cb->fill(cb, "active_file", (active_file) * PAGE_SIZE);
cb->fill(cb, "inactive_file", (inactive_file) * PAGE_SIZE);
cb->fill(cb, "unevictable", unevictable * PAGE_SIZE);
}
#ifdef CONFIG_DEBUG_VM
cb->fill(cb, "inactive_ratio", mem_cont->inactive_ratio);
{
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 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,
},
};
#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.
*
* When mem_cgroup is destroyed, mem->obsolete will be set to 0 and
* entry which points to this memcg will be ignore at swapin.
*
* Removal of cgroup itself succeeds regardless of refs from swap.
*/
static void mem_cgroup_free(struct mem_cgroup *mem)
{
int node;
if (atomic_read(&mem->refcnt) > 0)
return;
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)) {
if (!mem->obsolete)
return;
mem_cgroup_free(mem);
}
}
#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 *
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
struct mem_cgroup *mem, *parent;
int node;
mem = mem_cgroup_alloc();
if (!mem)
return ERR_PTR(-ENOMEM);
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);
} else {
res_counter_init(&mem->res, NULL);
res_counter_init(&mem->memsw, NULL);
}
mem_cgroup_set_inactive_ratio(mem);
mem->last_scanned_child = NULL;
spin_lock_init(&mem->reclaim_param_lock);
return &mem->css;
free_out:
for_each_node_state(node, N_POSSIBLE)
free_mem_cgroup_per_zone_info(mem, node);
mem_cgroup_free(mem);
return ERR_PTR(-ENOMEM);
}
static void mem_cgroup_pre_destroy(struct cgroup_subsys *ss,
struct cgroup *cont)
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
mem->obsolete = 1;
mem_cgroup_force_empty(mem, false);
}
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
struct cgroup *cont)
{
mem_cgroup_free(mem_cgroup_from_cont(cont));
}
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)
{
/*
* FIXME: It's better to move charges of this process from old
* memcg to new memcg. But it's just on TODO-List now.
*/
}
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,
};
#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