kernel_optimize_test/mm/memcontrol.c
KAMEZAWA Hiroyuki c077719be8 memcg: mem+swap controller Kconfig
Config and control variable for mem+swap controller.

This patch adds CONFIG_CGROUP_MEM_RES_CTLR_SWAP
(memory resource controller swap extension.)

For accounting swap, it's obvious that we have to use additional memory to
remember "who uses swap".  This adds more overhead.  So, it's better to
offer "choice" to users.  This patch adds 2 choices.

This patch adds 2 parameters to enable swap extension or not.
  - CONFIG
  - boot option

Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:05 -08:00

1527 lines
36 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/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
#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
*/
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 */
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_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);
}
#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_subsys.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)) {
ret = mem_cgroup_charge_common(page, mm, mask,
MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL);
}
if (!locked)
unlock_page(page);
return ret;
}
#endif
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;
if (PageSwapCache(page))
return;
/*
* Check if our page_cgroup is valid
*/
pc = lookup_page_cgroup(page);
if (unlikely(!pc || !PageCgroupUsed(pc)))
return;
lock_page_cgroup(pc);
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;
}
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;
unlock_out:
unlock_page_cgroup(pc);
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);
}
void mem_cgroup_uncharge_swapcache(struct page *page)
{
__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
}
/*
* 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)
__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);
}
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
static void __init enable_swap_cgroup(void)
{
if (!mem_cgroup_subsys.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;
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;
/* root ? */
if (cont->parent == NULL)
enable_swap_cgroup();
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,
};
#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