root/mm/memcontrol.c
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DEFINITIONS
This source file includes following definitions.
- __mem_cgroup_stat_add_safe
- mem_cgroup_read_stat
- page_cgroup_nid
- page_cgroup_zid
- mem_cgroup_charge_statistics
- mem_cgroup_zoneinfo
- page_cgroup_zoneinfo
- mem_cgroup_get_all_zonestat
- mem_cgroup_from_cont
- mem_cgroup_from_task
- page_cgroup_locked
- page_assign_page_cgroup
- page_get_page_cgroup
- lock_page_cgroup
- try_lock_page_cgroup
- unlock_page_cgroup
- __mem_cgroup_remove_list
- __mem_cgroup_add_list
- __mem_cgroup_move_lists
- task_in_mem_cgroup
- mem_cgroup_move_lists
- mem_cgroup_calc_mapped_ratio
- mem_cgroup_reclaim_imbalance
- mem_cgroup_get_reclaim_priority
- mem_cgroup_note_reclaim_priority
- mem_cgroup_record_reclaim_priority
- mem_cgroup_calc_reclaim_active
- mem_cgroup_calc_reclaim_inactive
- mem_cgroup_isolate_pages
- mem_cgroup_charge_common
- mem_cgroup_charge
- mem_cgroup_cache_charge
- __mem_cgroup_uncharge_common
- mem_cgroup_uncharge_page
- mem_cgroup_uncharge_cache_page
- mem_cgroup_prepare_migration
- mem_cgroup_end_migration
- mem_cgroup_shrink_usage
- mem_cgroup_resize_limit
- mem_cgroup_force_empty_list
- mem_cgroup_force_empty
- mem_cgroup_read
- mem_cgroup_write
- mem_cgroup_reset
- mem_force_empty_write
- mem_control_stat_show
- alloc_mem_cgroup_per_zone_info
- free_mem_cgroup_per_zone_info
- mem_cgroup_alloc
- mem_cgroup_free
- mem_cgroup_create
- mem_cgroup_pre_destroy
- mem_cgroup_destroy
- mem_cgroup_populate
- mem_cgroup_move_task
/* 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/smp.h>
#include <linux/page-flags.h>
#include <linux/backing-dev.h>
#include <linux/bit_spinlock.h>
#include <linux/rcupdate.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 <asm/uaccess.h>
struct cgroup_subsys mem_cgroup_subsys __read_mostly;
static struct kmem_cache *page_cgroup_cache __read_mostly;
#define MEM_CGROUP_RECLAIM_RETRIES 5
/*
* 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[NR_CPUS];
};
/*
* For accounting under irq disable, no need for increment preempt count.
*/
static void __mem_cgroup_stat_add_safe(struct mem_cgroup_stat *stat,
enum mem_cgroup_stat_index idx, int val)
{
int cpu = smp_processor_id();
stat->cpustat[cpu].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.
*/
enum mem_cgroup_zstat_index {
MEM_CGROUP_ZSTAT_ACTIVE,
MEM_CGROUP_ZSTAT_INACTIVE,
NR_MEM_CGROUP_ZSTAT,
};
struct mem_cgroup_per_zone {
/*
* spin_lock to protect the per cgroup LRU
*/
spinlock_t lru_lock;
struct list_head active_list;
struct list_head inactive_list;
unsigned long count[NR_MEM_CGROUP_ZSTAT];
};
/* 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;
/*
* Per cgroup active and inactive list, similar to the
* per zone LRU lists.
*/
struct mem_cgroup_lru_info info;
int prev_priority; /* for recording reclaim priority */
/*
* statistics.
*/
struct mem_cgroup_stat stat;
};
static struct mem_cgroup init_mem_cgroup;
/*
* We use the lower bit of the page->page_cgroup pointer as a bit spin
* lock. We need to ensure that page->page_cgroup is at least two
* byte aligned (based on comments from Nick Piggin). But since
* bit_spin_lock doesn't actually set that lock bit in a non-debug
* uniprocessor kernel, we should avoid setting it here too.
*/
#define PAGE_CGROUP_LOCK_BIT 0x0
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT)
#else
#define PAGE_CGROUP_LOCK 0x0
#endif
/*
* A page_cgroup page is associated with every page descriptor. The
* page_cgroup helps us identify information about the cgroup
*/
struct page_cgroup {
struct list_head lru; /* per cgroup LRU list */
struct page *page;
struct mem_cgroup *mem_cgroup;
int flags;
};
#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */
static int page_cgroup_nid(struct page_cgroup *pc)
{
return page_to_nid(pc->page);
}
static enum zone_type page_cgroup_zid(struct page_cgroup *pc)
{
return page_zonenum(pc->page);
}
enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
MEM_CGROUP_CHARGE_TYPE_MAPPED,
MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
};
/*
* Always modified under lru lock. Then, not necessary to preempt_disable()
*/
static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, int flags,
bool charge)
{
int val = (charge)? 1 : -1;
struct mem_cgroup_stat *stat = &mem->stat;
VM_BUG_ON(!irqs_disabled());
if (flags & PAGE_CGROUP_FLAG_CACHE)
__mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_CACHE, val);
else
__mem_cgroup_stat_add_safe(stat, MEM_CGROUP_STAT_RSS, val);
if (charge)
__mem_cgroup_stat_add_safe(stat,
MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
else
__mem_cgroup_stat_add_safe(stat,
MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
}
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);
return mem_cgroup_zoneinfo(mem, nid, zid);
}
static unsigned long mem_cgroup_get_all_zonestat(struct mem_cgroup *mem,
enum mem_cgroup_zstat_index 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 inline int page_cgroup_locked(struct page *page)
{
return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
}
static void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
{
VM_BUG_ON(!page_cgroup_locked(page));
page->page_cgroup = ((unsigned long)pc | PAGE_CGROUP_LOCK);
}
struct page_cgroup *page_get_page_cgroup(struct page *page)
{
return (struct page_cgroup *) (page->page_cgroup & ~PAGE_CGROUP_LOCK);
}
static void lock_page_cgroup(struct page *page)
{
bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
}
static int try_lock_page_cgroup(struct page *page)
{
return bit_spin_trylock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
}
static void unlock_page_cgroup(struct page *page)
{
bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
}
static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
struct page_cgroup *pc)
{
int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
if (from)
MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1;
else
MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1;
mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false);
list_del(&pc->lru);
}
static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
struct page_cgroup *pc)
{
int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
if (!to) {
MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1;
list_add(&pc->lru, &mz->inactive_list);
} else {
MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1;
list_add(&pc->lru, &mz->active_list);
}
mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, true);
}
static void __mem_cgroup_move_lists(struct page_cgroup *pc, bool active)
{
int from = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
if (from)
MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) -= 1;
else
MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1;
if (active) {
MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE) += 1;
pc->flags |= PAGE_CGROUP_FLAG_ACTIVE;
list_move(&pc->lru, &mz->active_list);
} else {
MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) += 1;
pc->flags &= ~PAGE_CGROUP_FLAG_ACTIVE;
list_move(&pc->lru, &mz->inactive_list);
}
}
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;
}
/*
* This routine assumes that the appropriate zone's lru lock is already held
*/
void mem_cgroup_move_lists(struct page *page, bool active)
{
struct page_cgroup *pc;
struct mem_cgroup_per_zone *mz;
unsigned long flags;
if (mem_cgroup_subsys.disabled)
return;
/*
* We cannot lock_page_cgroup while holding zone's lru_lock,
* because other holders of lock_page_cgroup can be interrupted
* with an attempt to rotate_reclaimable_page. But we cannot
* safely get to page_cgroup without it, so just try_lock it:
* mem_cgroup_isolate_pages allows for page left on wrong list.
*/
if (!try_lock_page_cgroup(page))
return;
pc = page_get_page_cgroup(page);
if (pc) {
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_move_lists(pc, active);
spin_unlock_irqrestore(&mz->lru_lock, flags);
}
unlock_page_cgroup(page);
}
/*
* 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);
}
/*
* This function is called from vmscan.c. In page reclaiming loop. balance
* between active and inactive list is calculated. For memory controller
* page reclaiming, we should use using mem_cgroup's imbalance rather than
* zone's global lru imbalance.
*/
long mem_cgroup_reclaim_imbalance(struct mem_cgroup *mem)
{
unsigned long active, inactive;
/* active and inactive are the number of pages. 'long' is ok.*/
active = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_ACTIVE);
inactive = mem_cgroup_get_all_zonestat(mem, MEM_CGROUP_ZSTAT_INACTIVE);
return (long) (active / (inactive + 1));
}
/*
* prev_priority control...this will be used in memory reclaim path.
*/
int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
{
return mem->prev_priority;
}
void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority)
{
if (priority < mem->prev_priority)
mem->prev_priority = priority;
}
void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority)
{
mem->prev_priority = priority;
}
/*
* Calculate # of pages to be scanned in this priority/zone.
* See also vmscan.c
*
* priority starts from "DEF_PRIORITY" and decremented in each loop.
* (see include/linux/mmzone.h)
*/
long mem_cgroup_calc_reclaim_active(struct mem_cgroup *mem,
struct zone *zone, int priority)
{
long nr_active;
int nid = zone->zone_pgdat->node_id;
int zid = zone_idx(zone);
struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
nr_active = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_ACTIVE);
return (nr_active >> priority);
}
long mem_cgroup_calc_reclaim_inactive(struct mem_cgroup *mem,
struct zone *zone, int priority)
{
long nr_inactive;
int nid = zone->zone_pgdat->node_id;
int zid = zone_idx(zone);
struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(mem, nid, zid);
nr_inactive = MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE);
return (nr_inactive >> priority);
}
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)
{
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;
BUG_ON(!mem_cont);
mz = mem_cgroup_zoneinfo(mem_cont, nid, zid);
if (active)
src = &mz->active_list;
else
src = &mz->inactive_list;
spin_lock(&mz->lru_lock);
scan = 0;
list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
if (scan >= nr_to_scan)
break;
page = pc->page;
if (unlikely(!PageLRU(page)))
continue;
if (PageActive(page) && !active) {
__mem_cgroup_move_lists(pc, true);
continue;
}
if (!PageActive(page) && active) {
__mem_cgroup_move_lists(pc, false);
continue;
}
scan++;
list_move(&pc->lru, &pc_list);
if (__isolate_lru_page(page, mode) == 0) {
list_move(&page->lru, dst);
nr_taken++;
}
}
list_splice(&pc_list, src);
spin_unlock(&mz->lru_lock);
*scanned = scan;
return nr_taken;
}
/*
* 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;
unsigned long flags;
unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
struct mem_cgroup_per_zone *mz;
pc = kmem_cache_alloc(page_cgroup_cache, gfp_mask);
if (unlikely(pc == NULL))
goto err;
/*
* 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();
kmem_cache_free(page_cgroup_cache, pc);
return 0;
}
/*
* For every charge from the cgroup, increment reference count
*/
css_get(&mem->css);
rcu_read_unlock();
} else {
mem = memcg;
css_get(&memcg->css);
}
while (res_counter_charge(&mem->res, PAGE_SIZE)) {
if (!(gfp_mask & __GFP_WAIT))
goto out;
if (try_to_free_mem_cgroup_pages(mem, gfp_mask))
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 (res_counter_check_under_limit(&mem->res))
continue;
if (!nr_retries--) {
mem_cgroup_out_of_memory(mem, gfp_mask);
goto out;
}
}
pc->mem_cgroup = mem;
pc->page = page;
/*
* If a page is accounted as a page cache, insert to inactive list.
* If anon, insert to active list.
*/
if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
pc->flags = PAGE_CGROUP_FLAG_CACHE;
else
pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
lock_page_cgroup(page);
if (unlikely(page_get_page_cgroup(page))) {
unlock_page_cgroup(page);
res_counter_uncharge(&mem->res, PAGE_SIZE);
css_put(&mem->css);
kmem_cache_free(page_cgroup_cache, pc);
goto done;
}
page_assign_page_cgroup(page, pc);
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_add_list(mz, pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
unlock_page_cgroup(page);
done:
return 0;
out:
css_put(&mem->css);
kmem_cache_free(page_cgroup_cache, pc);
err:
return -ENOMEM;
}
int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
{
if (mem_cgroup_subsys.disabled)
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_subsys.disabled)
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;
lock_page_cgroup(page);
pc = page_get_page_cgroup(page);
if (pc) {
VM_BUG_ON(pc->page != page);
VM_BUG_ON(!pc->mem_cgroup);
unlock_page_cgroup(page);
return 0;
}
unlock_page_cgroup(page);
}
if (unlikely(!mm))
mm = &init_mm;
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
}
/*
* uncharge if !page_mapped(page)
*/
static void
__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
{
struct page_cgroup *pc;
struct mem_cgroup *mem;
struct mem_cgroup_per_zone *mz;
unsigned long flags;
if (mem_cgroup_subsys.disabled)
return;
/*
* Check if our page_cgroup is valid
*/
lock_page_cgroup(page);
pc = page_get_page_cgroup(page);
if (unlikely(!pc))
goto unlock;
VM_BUG_ON(pc->page != page);
if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
&& ((pc->flags & PAGE_CGROUP_FLAG_CACHE)
|| page_mapped(page)))
goto unlock;
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_remove_list(mz, pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
page_assign_page_cgroup(page, NULL);
unlock_page_cgroup(page);
mem = pc->mem_cgroup;
res_counter_uncharge(&mem->res, PAGE_SIZE);
css_put(&mem->css);
kmem_cache_free(page_cgroup_cache, pc);
return;
unlock:
unlock_page_cgroup(page);
}
void mem_cgroup_uncharge_page(struct page *page)
{
__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));
__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
}
/*
* Before starting migration, account against new page.
*/
int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
{
struct page_cgroup *pc;
struct mem_cgroup *mem = NULL;
enum charge_type ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
int ret = 0;
if (mem_cgroup_subsys.disabled)
return 0;
lock_page_cgroup(page);
pc = page_get_page_cgroup(page);
if (pc) {
mem = pc->mem_cgroup;
css_get(&mem->css);
if (pc->flags & PAGE_CGROUP_FLAG_CACHE)
ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
}
unlock_page_cgroup(page);
if (mem) {
ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL,
ctype, mem);
css_put(&mem->css);
}
return ret;
}
/* remove redundant charge if migration failed*/
void mem_cgroup_end_migration(struct page *newpage)
{
/*
* At success, page->mapping is not NULL.
* special rollback care is necessary when
* 1. at migration failure. (newpage->mapping is cleared in this case)
* 2. the newpage was moved but not remapped again because the task
* exits and the newpage is obsolete. In this case, the new page
* may be a swapcache. So, we just call mem_cgroup_uncharge_page()
* always for avoiding mess. The page_cgroup will be removed if
* unnecessary. File cache pages is still on radix-tree. Don't
* care it.
*/
if (!newpage->mapping)
__mem_cgroup_uncharge_common(newpage,
MEM_CGROUP_CHARGE_TYPE_FORCE);
else if (PageAnon(newpage))
mem_cgroup_uncharge_page(newpage);
}
/*
* 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_subsys.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);
progress += res_counter_check_under_limit(&mem->res);
} while (!progress && --retry);
css_put(&mem->css);
if (!retry)
return -ENOMEM;
return 0;
}
int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
{
int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
int progress;
int ret = 0;
while (res_counter_set_limit(&memcg->res, val)) {
if (signal_pending(current)) {
ret = -EINTR;
break;
}
if (!retry_count) {
ret = -EBUSY;
break;
}
progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL);
if (!progress)
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.
*/
#define FORCE_UNCHARGE_BATCH (128)
static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
struct mem_cgroup_per_zone *mz,
int active)
{
struct page_cgroup *pc;
struct page *page;
int count = FORCE_UNCHARGE_BATCH;
unsigned long flags;
struct list_head *list;
if (active)
list = &mz->active_list;
else
list = &mz->inactive_list;
spin_lock_irqsave(&mz->lru_lock, flags);
while (!list_empty(list)) {
pc = list_entry(list->prev, struct page_cgroup, lru);
page = pc->page;
get_page(page);
spin_unlock_irqrestore(&mz->lru_lock, flags);
/*
* Check if this page is on LRU. !LRU page can be found
* if it's under page migration.
*/
if (PageLRU(page)) {
__mem_cgroup_uncharge_common(page,
MEM_CGROUP_CHARGE_TYPE_FORCE);
put_page(page);
if (--count <= 0) {
count = FORCE_UNCHARGE_BATCH;
cond_resched();
}
} else
cond_resched();
spin_lock_irqsave(&mz->lru_lock, flags);
}
spin_unlock_irqrestore(&mz->lru_lock, flags);
}
/*
* 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)
{
int ret = -EBUSY;
int node, zid;
css_get(&mem->css);
/*
* page reclaim code (kswapd etc..) will move pages between
* active_list <-> inactive_list while we don't take a lock.
* So, we have to do loop here until all lists are empty.
*/
while (mem->res.usage > 0) {
if (atomic_read(&mem->css.cgroup->count) > 0)
goto out;
for_each_node_state(node, N_POSSIBLE)
for (zid = 0; zid < MAX_NR_ZONES; zid++) {
struct mem_cgroup_per_zone *mz;
mz = mem_cgroup_zoneinfo(mem, node, zid);
/* drop all page_cgroup in active_list */
mem_cgroup_force_empty_list(mem, mz, 1);
/* drop all page_cgroup in inactive_list */
mem_cgroup_force_empty_list(mem, mz, 0);
}
}
ret = 0;
out:
css_put(&mem->css);
return ret;
}
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
{
return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
cft->private);
}
/*
* 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);
unsigned long long val;
int ret;
switch (cft->private) {
case RES_LIMIT:
/* This function does all necessary parse...reuse it */
ret = res_counter_memparse_write_strategy(buffer, &val);
if (!ret)
ret = mem_cgroup_resize_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;
mem = mem_cgroup_from_cont(cont);
switch (event) {
case RES_MAX_USAGE:
res_counter_reset_max(&mem->res);
break;
case RES_FAILCNT:
res_counter_reset_failcnt(&mem->res);
break;
}
return 0;
}
static int mem_force_empty_write(struct cgroup *cont, unsigned int event)
{
return mem_cgroup_force_empty(mem_cgroup_from_cont(cont));
}
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, inactive;
inactive = mem_cgroup_get_all_zonestat(mem_cont,
MEM_CGROUP_ZSTAT_INACTIVE);
active = mem_cgroup_get_all_zonestat(mem_cont,
MEM_CGROUP_ZSTAT_ACTIVE);
cb->fill(cb, "active", (active) * PAGE_SIZE);
cb->fill(cb, "inactive", (inactive) * PAGE_SIZE);
}
return 0;
}
static struct cftype mem_cgroup_files[] = {
{
.name = "usage_in_bytes",
.private = RES_USAGE,
.read_u64 = mem_cgroup_read,
},
{
.name = "max_usage_in_bytes",
.private = RES_MAX_USAGE,
.trigger = mem_cgroup_reset,
.read_u64 = mem_cgroup_read,
},
{
.name = "limit_in_bytes",
.private = RES_LIMIT,
.write_string = mem_cgroup_write,
.read_u64 = mem_cgroup_read,
},
{
.name = "failcnt",
.private = RES_FAILCNT,
.trigger = mem_cgroup_reset,
.read_u64 = mem_cgroup_read,
},
{
.name = "force_empty",
.trigger = mem_force_empty_write,
},
{
.name = "stat",
.read_map = mem_control_stat_show,
},
};
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;
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];
INIT_LIST_HEAD(&mz->active_list);
INIT_LIST_HEAD(&mz->inactive_list);
spin_lock_init(&mz->lru_lock);
}
return 0;
}
static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
{
kfree(mem->info.nodeinfo[node]);
}
static struct mem_cgroup *mem_cgroup_alloc(void)
{
struct mem_cgroup *mem;
if (sizeof(*mem) < PAGE_SIZE)
mem = kmalloc(sizeof(*mem), GFP_KERNEL);
else
mem = vmalloc(sizeof(*mem));
if (mem)
memset(mem, 0, sizeof(*mem));
return mem;
}
static void mem_cgroup_free(struct mem_cgroup *mem)
{
if (sizeof(*mem) < PAGE_SIZE)
kfree(mem);
else
vfree(mem);
}
static struct cgroup_subsys_state *
mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
{
struct mem_cgroup *mem;
int node;
if (unlikely((cont->parent) == NULL)) {
mem = &init_mem_cgroup;
page_cgroup_cache = KMEM_CACHE(page_cgroup, SLAB_PANIC);
} else {
mem = mem_cgroup_alloc();
if (!mem)
return ERR_PTR(-ENOMEM);
}
res_counter_init(&mem->res);
for_each_node_state(node, N_POSSIBLE)
if (alloc_mem_cgroup_per_zone_info(mem, node))
goto free_out;
return &mem->css;
free_out:
for_each_node_state(node, N_POSSIBLE)
free_mem_cgroup_per_zone_info(mem, node);
if (cont->parent != NULL)
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_cgroup_force_empty(mem);
}
static void mem_cgroup_destroy(struct cgroup_subsys *ss,
struct cgroup *cont)
{
int node;
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
for_each_node_state(node, N_POSSIBLE)
free_mem_cgroup_per_zone_info(mem, node);
mem_cgroup_free(mem_cgroup_from_cont(cont));
}
static int mem_cgroup_populate(struct cgroup_subsys *ss,
struct cgroup *cont)
{
return cgroup_add_files(cont, ss, mem_cgroup_files,
ARRAY_SIZE(mem_cgroup_files));
}
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
struct cgroup *cont,
struct cgroup *old_cont,
struct task_struct *p)
{
struct mm_struct *mm;
struct mem_cgroup *mem, *old_mem;
mm = get_task_mm(p);
if (mm == NULL)
return;
mem = mem_cgroup_from_cont(cont);
old_mem = mem_cgroup_from_cont(old_cont);
/*
* Only thread group leaders are allowed to migrate, the mm_struct is
* in effect owned by the leader
*/
if (!thread_group_leader(p))
goto out;
out:
mmput(mm);
}
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,
};