linux/mm/memcontrol.c

1438 lines
34 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/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 <linux/mm_inline.h>
#include <linux/page_cgroup.h>
#include <asm/uaccess.h>
struct cgroup_subsys mem_cgroup_subsys __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[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
*/
spinlock_t lru_lock;
struct list_head lists[NR_LRU_LISTS];
unsigned long count[NR_LRU_LISTS];
};
/* 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. 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 */
NR_CHARGE_TYPE,
};
/* only for here (for easy reading.) */
#define PCGF_CACHE (1UL << PCG_CACHE)
#define PCGF_USED (1UL << PCG_USED)
#define PCGF_ACTIVE (1UL << PCG_ACTIVE)
#define PCGF_LOCK (1UL << PCG_LOCK)
#define PCGF_FILE (1UL << PCG_FILE)
static const unsigned long
pcg_default_flags[NR_CHARGE_TYPE] = {
PCGF_CACHE | PCGF_FILE | PCGF_USED | PCGF_LOCK, /* File Cache */
PCGF_ACTIVE | PCGF_USED | PCGF_LOCK, /* Anon */
PCGF_ACTIVE | PCGF_CACHE | PCGF_USED | PCGF_LOCK, /* Shmem */
0, /* FORCE */
};
/*
* Always modified under lru lock. Then, not necessary to preempt_disable()
*/
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;
VM_BUG_ON(!irqs_disabled());
cpustat = &stat->cpustat[smp_processor_id()];
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);
}
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 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 void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
struct page_cgroup *pc)
{
int lru = LRU_BASE;
if (PageCgroupUnevictable(pc))
lru = LRU_UNEVICTABLE;
else {
if (PageCgroupActive(pc))
lru += LRU_ACTIVE;
if (PageCgroupFile(pc))
lru += LRU_FILE;
}
MEM_CGROUP_ZSTAT(mz, lru) -= 1;
mem_cgroup_charge_statistics(pc->mem_cgroup, pc, false);
list_del(&pc->lru);
}
static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
struct page_cgroup *pc, bool hot)
{
int lru = LRU_BASE;
if (PageCgroupUnevictable(pc))
lru = LRU_UNEVICTABLE;
else {
if (PageCgroupActive(pc))
lru += LRU_ACTIVE;
if (PageCgroupFile(pc))
lru += LRU_FILE;
}
MEM_CGROUP_ZSTAT(mz, lru) += 1;
if (hot)
list_add(&pc->lru, &mz->lists[lru]);
else
list_add_tail(&pc->lru, &mz->lists[lru]);
mem_cgroup_charge_statistics(pc->mem_cgroup, pc, true);
}
static void __mem_cgroup_move_lists(struct page_cgroup *pc, enum lru_list lru)
{
struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
int active = PageCgroupActive(pc);
int file = PageCgroupFile(pc);
int unevictable = PageCgroupUnevictable(pc);
enum lru_list from = unevictable ? LRU_UNEVICTABLE :
(LRU_FILE * !!file + !!active);
if (lru == from)
return;
MEM_CGROUP_ZSTAT(mz, from) -= 1;
/*
* However this is done under mz->lru_lock, another flags, which
* are not related to LRU, will be modified from out-of-lock.
* We have to use atomic set/clear flags.
*/
if (is_unevictable_lru(lru)) {
ClearPageCgroupActive(pc);
SetPageCgroupUnevictable(pc);
} else {
if (is_active_lru(lru))
SetPageCgroupActive(pc);
else
ClearPageCgroupActive(pc);
ClearPageCgroupUnevictable(pc);
}
MEM_CGROUP_ZSTAT(mz, lru) += 1;
list_move(&pc->lru, &mz->lists[lru]);
}
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, enum lru_list lru)
{
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.
*/
pc = lookup_page_cgroup(page);
if (!trylock_page_cgroup(pc))
return;
if (pc && PageCgroupUsed(pc)) {
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_move_lists(pc, lru);
spin_unlock_irqrestore(&mz->lru_lock, flags);
}
unlock_page_cgroup(pc);
}
/*
* 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)
{
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(struct mem_cgroup *mem, struct zone *zone,
int priority, enum lru_list lru)
{
long nr_pages;
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_pages = MEM_CGROUP_ZSTAT(mz, lru);
return (nr_pages >> 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, 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];
spin_lock(&mz->lru_lock);
scan = 0;
list_for_each_entry_safe_reverse(pc, tmp, src, lru) {
if (scan >= nr_to_scan)
break;
if (unlikely(!PageCgroupUsed(pc)))
continue;
page = pc->page;
if (unlikely(!PageLRU(page)))
continue;
/*
* TODO: play better with lumpy reclaim, grabbing anything.
*/
if (PageUnevictable(page) ||
(PageActive(page) && !active) ||
(!PageActive(page) && active)) {
__mem_cgroup_move_lists(pc, page_lru(page));
continue;
}
scan++;
list_move(&pc->lru, &pc_list);
if (__isolate_lru_page(page, mode, file) == 0) {
list_move(&page->lru, dst);
nr_taken++;
}
}
list_splice(&pc_list, src);
spin_unlock(&mz->lru_lock);
*scanned = scan;
return nr_taken;
}
/*
* 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;
int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
/*
* 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 (unlikely(res_counter_charge(&mem->res, PAGE_SIZE))) {
if (!(gfp_mask & __GFP_WAIT))
goto nomem;
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--) {
if (oom)
mem_cgroup_out_of_memory(mem, gfp_mask);
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)
{
struct mem_cgroup_per_zone *mz;
unsigned long flags;
/* 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);
css_put(&mem->css);
return;
}
pc->mem_cgroup = mem;
/*
* If a page is accounted as a page cache, insert to inactive list.
* If anon, insert to active list.
*/
pc->flags = pcg_default_flags[ctype];
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_add_list(mz, pc, true);
spin_unlock_irqrestore(&mz->lru_lock, flags);
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.
* 1. disable irq.
* 2. lru_lock of old mem_cgroup(@from) should be held.
*
* 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(!irqs_disabled());
VM_BUG_ON(from == to);
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;
if (spin_trylock(&to_mz->lru_lock)) {
__mem_cgroup_remove_list(from_mz, pc);
css_put(&from->css);
res_counter_uncharge(&from->res, PAGE_SIZE);
pc->mem_cgroup = to;
css_get(&to->css);
__mem_cgroup_add_list(to_mz, pc, false);
ret = 0;
spin_unlock(&to_mz->lru_lock);
}
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 cgroup *cg = child->css.cgroup;
struct cgroup *pcg = cg->parent;
struct mem_cgroup *parent;
struct mem_cgroup_per_zone *mz;
unsigned long flags;
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)
return ret;
mz = mem_cgroup_zoneinfo(child,
page_cgroup_nid(pc), page_cgroup_zid(pc));
spin_lock_irqsave(&mz->lru_lock, flags);
ret = mem_cgroup_move_account(pc, child, parent);
spin_unlock_irqrestore(&mz->lru_lock, flags);
/* drop extra refcnt */
css_put(&parent->css);
/* uncharge if move fails */
if (ret)
res_counter_uncharge(&parent->res, 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)
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_subsys.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_subsys.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);
}
void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
{
struct page_cgroup *pc;
if (mem_cgroup_subsys.disabled)
return;
if (!ptr)
return;
pc = lookup_page_cgroup(page);
__mem_cgroup_commit_charge(ptr, pc, MEM_CGROUP_CHARGE_TYPE_MAPPED);
}
void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
{
if (mem_cgroup_subsys.disabled)
return;
if (!mem)
return;
res_counter_uncharge(&mem->res, PAGE_SIZE);
css_put(&mem->css);
}
/*
* 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
*/
pc = lookup_page_cgroup(page);
if (unlikely(!pc || !PageCgroupUsed(pc)))
return;
lock_page_cgroup(pc);
if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED && page_mapped(page))
|| !PageCgroupUsed(pc)) {
/* This happens at race in zap_pte_range() and do_swap_page()*/
unlock_page_cgroup(pc);
return;
}
ClearPageCgroupUsed(pc);
mem = pc->mem_cgroup;
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);
unlock_page_cgroup(pc);
res_counter_uncharge(&mem->res, PAGE_SIZE);
css_put(&mem->css);
return;
}
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);
}
/*
* 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_subsys.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_HIGHUSER_MOVABLE, &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 && ctype != MEM_CGROUP_CHARGE_TYPE_MAPPED)
__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_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;
}
static 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_HIGHUSER_MOVABLE);
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.
*/
static int mem_cgroup_force_empty_list(struct mem_cgroup *mem,
struct mem_cgroup_per_zone *mz,
enum lru_list lru)
{
struct page_cgroup *pc, *busy;
unsigned long flags;
unsigned long loop;
struct list_head *list;
int ret = 0;
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(&mz->lru_lock, flags);
if (list_empty(list)) {
spin_unlock_irqrestore(&mz->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(&mz->lru_lock, flags);
continue;
}
spin_unlock_irqrestore(&mz->lru_lock, flags);
ret = mem_cgroup_move_parent(pc, mem, GFP_HIGHUSER_MOVABLE);
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++) {
struct mem_cgroup_per_zone *mz;
enum lru_list l;
mz = mem_cgroup_zoneinfo(mem, node, zid);
for_each_lru(l) {
ret = mem_cgroup_force_empty_list(mem,
mz, 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_HIGHUSER_MOVABLE);
if (!progress) {
nr_retries--;
/* maybe some writeback is necessary */
congestion_wait(WRITE, HZ/10);
}
}
/* 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_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 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);
}
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 = "stat",
.read_map = mem_control_stat_show,
},
{
.name = "force_empty",
.trigger = mem_cgroup_force_empty_write,
},
};
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];
spin_lock_init(&mz->lru_lock);
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;
}
static void mem_cgroup_free(struct mem_cgroup *mem)
{
if (mem_cgroup_size() < 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;
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);
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, false);
}
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,
};