blob: bb4d7acfbca3fc0177b213c86db6caf9ad41cf12 [file] [log] [blame]
/* 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/swap.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
struct cgroup_subsys mem_cgroup_subsys;
static const int 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_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;
};
/*
* 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 atleast two
* byte aligned (based on comments from Nick Piggin)
*/
#define PAGE_CGROUP_LOCK_BIT 0x0
#define PAGE_CGROUP_LOCK (1 << PAGE_CGROUP_LOCK_BIT)
/*
* 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;
atomic_t ref_cnt; /* Helpful when pages move b/w */
/* mapped and cached states */
int flags;
};
#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
#define PAGE_CGROUP_FLAG_ACTIVE (0x2) /* page is active in this cgroup */
static inline int page_cgroup_nid(struct page_cgroup *pc)
{
return page_to_nid(pc->page);
}
static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
{
return page_zonenum(pc->page);
}
enum {
MEM_CGROUP_TYPE_UNSPEC = 0,
MEM_CGROUP_TYPE_MAPPED,
MEM_CGROUP_TYPE_CACHED,
MEM_CGROUP_TYPE_ALL,
MEM_CGROUP_TYPE_MAX,
};
enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
MEM_CGROUP_CHARGE_TYPE_MAPPED,
};
/*
* 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);
}
static inline struct mem_cgroup_per_zone *
mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid)
{
BUG_ON(!mem->info.nodeinfo[nid]);
return &mem->info.nodeinfo[nid]->zoneinfo[zid];
}
static inline 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 init_mem_cgroup;
static inline
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);
}
static inline
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
{
return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
struct mem_cgroup, css);
}
void mm_init_cgroup(struct mm_struct *mm, struct task_struct *p)
{
struct mem_cgroup *mem;
mem = mem_cgroup_from_task(p);
css_get(&mem->css);
mm->mem_cgroup = mem;
}
void mm_free_cgroup(struct mm_struct *mm)
{
css_put(&mm->mem_cgroup->css);
}
static inline int page_cgroup_locked(struct page *page)
{
return bit_spin_is_locked(PAGE_CGROUP_LOCK_BIT,
&page->page_cgroup);
}
void page_assign_page_cgroup(struct page *page, struct page_cgroup *pc)
{
int locked;
/*
* While resetting the page_cgroup we might not hold the
* page_cgroup lock. free_hot_cold_page() is an example
* of such a scenario
*/
if (pc)
VM_BUG_ON(!page_cgroup_locked(page));
locked = (page->page_cgroup & PAGE_CGROUP_LOCK);
page->page_cgroup = ((unsigned long)pc | locked);
}
struct page_cgroup *page_get_page_cgroup(struct page *page)
{
return (struct page_cgroup *)
(page->page_cgroup & ~PAGE_CGROUP_LOCK);
}
static void __always_inline lock_page_cgroup(struct page *page)
{
bit_spin_lock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
VM_BUG_ON(!page_cgroup_locked(page));
}
static void __always_inline unlock_page_cgroup(struct page *page)
{
bit_spin_unlock(PAGE_CGROUP_LOCK_BIT, &page->page_cgroup);
}
/*
* Tie new page_cgroup to struct page under lock_page_cgroup()
* This can fail if the page has been tied to a page_cgroup.
* If success, returns 0.
*/
static int page_cgroup_assign_new_page_cgroup(struct page *page,
struct page_cgroup *pc)
{
int ret = 0;
lock_page_cgroup(page);
if (!page_get_page_cgroup(page))
page_assign_page_cgroup(page, pc);
else /* A page is tied to other pc. */
ret = 1;
unlock_page_cgroup(page);
return ret;
}
/*
* Clear page->page_cgroup member under lock_page_cgroup().
* If given "pc" value is different from one page->page_cgroup,
* page->cgroup is not cleared.
* Returns a value of page->page_cgroup at lock taken.
* A can can detect failure of clearing by following
* clear_page_cgroup(page, pc) == pc
*/
static struct page_cgroup *clear_page_cgroup(struct page *page,
struct page_cgroup *pc)
{
struct page_cgroup *ret;
/* lock and clear */
lock_page_cgroup(page);
ret = page_get_page_cgroup(page);
if (likely(ret == pc))
page_assign_page_cgroup(page, NULL);
unlock_page_cgroup(page);
return ret;
}
static void __mem_cgroup_remove_list(struct page_cgroup *pc)
{
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;
mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false);
list_del_init(&pc->lru);
}
static void __mem_cgroup_add_list(struct page_cgroup *pc)
{
int to = pc->flags & PAGE_CGROUP_FLAG_ACTIVE;
struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
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 && vm_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_cgroup *pc, bool active)
{
struct mem_cgroup_per_zone *mz;
unsigned long flags;
if (!pc)
return;
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);
}
/*
* 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;
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 *mem;
struct page_cgroup *pc;
unsigned long flags;
unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
struct mem_cgroup_per_zone *mz;
/*
* Should page_cgroup's go to their own slab?
* One could optimize the performance of the charging routine
* by saving a bit in the page_flags and using it as a lock
* to see if the cgroup page already has a page_cgroup associated
* with it
*/
retry:
if (page) {
lock_page_cgroup(page);
pc = page_get_page_cgroup(page);
/*
* The page_cgroup exists and
* the page has already been accounted.
*/
if (pc) {
if (unlikely(!atomic_inc_not_zero(&pc->ref_cnt))) {
/* this page is under being uncharged ? */
unlock_page_cgroup(page);
cpu_relax();
goto retry;
} else {
unlock_page_cgroup(page);
goto done;
}
}
unlock_page_cgroup(page);
}
pc = kzalloc(sizeof(struct page_cgroup), gfp_mask);
if (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 (!mm)
mm = &init_mm;
rcu_read_lock();
mem = rcu_dereference(mm->mem_cgroup);
/*
* For every charge from the cgroup, increment reference
* count
*/
css_get(&mem->css);
rcu_read_unlock();
/*
* If we created the page_cgroup, we should free it on exceeding
* the cgroup limit.
*/
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;
}
congestion_wait(WRITE, HZ/10);
}
atomic_set(&pc->ref_cnt, 1);
pc->mem_cgroup = mem;
pc->page = page;
pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
pc->flags |= PAGE_CGROUP_FLAG_CACHE;
if (!page || page_cgroup_assign_new_page_cgroup(page, pc)) {
/*
* Another charge has been added to this page already.
* We take lock_page_cgroup(page) again and read
* page->cgroup, increment refcnt.... just retry is OK.
*/
res_counter_uncharge(&mem->res, PAGE_SIZE);
css_put(&mem->css);
kfree(pc);
if (!page)
goto done;
goto retry;
}
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
/* Update statistics vector */
__mem_cgroup_add_list(pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
done:
return 0;
out:
css_put(&mem->css);
kfree(pc);
err:
return -ENOMEM;
}
int mem_cgroup_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
return mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_MAPPED);
}
/*
* See if the cached pages should be charged at all?
*/
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
int ret = 0;
if (!mm)
mm = &init_mm;
ret = mem_cgroup_charge_common(page, mm, gfp_mask,
MEM_CGROUP_CHARGE_TYPE_CACHE);
return ret;
}
/*
* Uncharging is always a welcome operation, we never complain, simply
* uncharge. This routine should be called with lock_page_cgroup held
*/
void mem_cgroup_uncharge(struct page_cgroup *pc)
{
struct mem_cgroup *mem;
struct mem_cgroup_per_zone *mz;
struct page *page;
unsigned long flags;
/*
* Check if our page_cgroup is valid
*/
if (!pc)
return;
if (atomic_dec_and_test(&pc->ref_cnt)) {
page = pc->page;
mz = page_cgroup_zoneinfo(pc);
/*
* get page->cgroup and clear it under lock.
* force_empty can drop page->cgroup without checking refcnt.
*/
unlock_page_cgroup(page);
if (clear_page_cgroup(page, pc) == pc) {
mem = pc->mem_cgroup;
css_put(&mem->css);
res_counter_uncharge(&mem->res, PAGE_SIZE);
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_remove_list(pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
kfree(pc);
}
lock_page_cgroup(page);
}
}
void mem_cgroup_uncharge_page(struct page *page)
{
lock_page_cgroup(page);
mem_cgroup_uncharge(page_get_page_cgroup(page));
unlock_page_cgroup(page);
}
/*
* Returns non-zero if a page (under migration) has valid page_cgroup member.
* Refcnt of page_cgroup is incremented.
*/
int mem_cgroup_prepare_migration(struct page *page)
{
struct page_cgroup *pc;
int ret = 0;
lock_page_cgroup(page);
pc = page_get_page_cgroup(page);
if (pc && atomic_inc_not_zero(&pc->ref_cnt))
ret = 1;
unlock_page_cgroup(page);
return ret;
}
void mem_cgroup_end_migration(struct page *page)
{
struct page_cgroup *pc;
lock_page_cgroup(page);
pc = page_get_page_cgroup(page);
mem_cgroup_uncharge(pc);
unlock_page_cgroup(page);
}
/*
* We know both *page* and *newpage* are now not-on-LRU and Pg_locked.
* And no race with uncharge() routines because page_cgroup for *page*
* has extra one reference by mem_cgroup_prepare_migration.
*/
void mem_cgroup_page_migration(struct page *page, struct page *newpage)
{
struct page_cgroup *pc;
struct mem_cgroup *mem;
unsigned long flags;
struct mem_cgroup_per_zone *mz;
retry:
pc = page_get_page_cgroup(page);
if (!pc)
return;
mem = pc->mem_cgroup;
mz = page_cgroup_zoneinfo(pc);
if (clear_page_cgroup(page, pc) != pc)
goto retry;
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_remove_list(pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
pc->page = newpage;
lock_page_cgroup(newpage);
page_assign_page_cgroup(newpage, pc);
unlock_page_cgroup(newpage);
mz = page_cgroup_zoneinfo(pc);
spin_lock_irqsave(&mz->lru_lock, flags);
__mem_cgroup_add_list(pc);
spin_unlock_irqrestore(&mz->lru_lock, flags);
return;
}
/*
* This routine traverse page_cgroup in given list and drop them all.
* This routine ignores page_cgroup->ref_cnt.
* *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;
unsigned long flags;
struct list_head *list;
if (active)
list = &mz->active_list;
else
list = &mz->inactive_list;
if (list_empty(list))
return;
retry:
count = FORCE_UNCHARGE_BATCH;
spin_lock_irqsave(&mz->lru_lock, flags);
while (--count && !list_empty(list)) {
pc = list_entry(list->prev, struct page_cgroup, lru);
page = pc->page;
/* Avoid race with charge */
atomic_set(&pc->ref_cnt, 0);
if (clear_page_cgroup(page, pc) == pc) {
css_put(&mem->css);
res_counter_uncharge(&mem->res, PAGE_SIZE);
__mem_cgroup_remove_list(pc);
kfree(pc);
} else /* being uncharged ? ...do relax */
break;
}
spin_unlock_irqrestore(&mz->lru_lock, flags);
if (!list_empty(list)) {
cond_resched();
goto retry;
}
return;
}
/*
* make mem_cgroup's charge to be 0 if there is no task.
* This enables deleting this mem_cgroup.
*/
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;
}
int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
{
*tmp = memparse(buf, &buf);
if (*buf != '\0')
return -EINVAL;
/*
* Round up the value to the closest page size
*/
*tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT;
return 0;
}
static ssize_t mem_cgroup_read(struct cgroup *cont,
struct cftype *cft, struct file *file,
char __user *userbuf, size_t nbytes, loff_t *ppos)
{
return res_counter_read(&mem_cgroup_from_cont(cont)->res,
cft->private, userbuf, nbytes, ppos,
NULL);
}
static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
struct file *file, const char __user *userbuf,
size_t nbytes, loff_t *ppos)
{
return res_counter_write(&mem_cgroup_from_cont(cont)->res,
cft->private, userbuf, nbytes, ppos,
mem_cgroup_write_strategy);
}
static ssize_t mem_force_empty_write(struct cgroup *cont,
struct cftype *cft, struct file *file,
const char __user *userbuf,
size_t nbytes, loff_t *ppos)
{
struct mem_cgroup *mem = mem_cgroup_from_cont(cont);
int ret;
ret = mem_cgroup_force_empty(mem);
if (!ret)
ret = nbytes;
return ret;
}
/*
* Note: This should be removed if cgroup supports write-only file.
*/
static ssize_t mem_force_empty_read(struct cgroup *cont,
struct cftype *cft,
struct file *file, char __user *userbuf,
size_t nbytes, loff_t *ppos)
{
return -EINVAL;
}
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, },
};
static int mem_control_stat_show(struct seq_file *m, void *arg)
{
struct cgroup *cont = m->private;
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;
seq_printf(m, "%s %lld\n", mem_cgroup_stat_desc[i].msg,
(long long)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);
seq_printf(m, "active %ld\n", (active) * PAGE_SIZE);
seq_printf(m, "inactive %ld\n", (inactive) * PAGE_SIZE);
}
return 0;
}
static const struct file_operations mem_control_stat_file_operations = {
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int mem_control_stat_open(struct inode *unused, struct file *file)
{
/* XXX __d_cont */
struct cgroup *cont = file->f_dentry->d_parent->d_fsdata;
file->f_op = &mem_control_stat_file_operations;
return single_open(file, mem_control_stat_show, cont);
}
static struct cftype mem_cgroup_files[] = {
{
.name = "usage_in_bytes",
.private = RES_USAGE,
.read = mem_cgroup_read,
},
{
.name = "limit_in_bytes",
.private = RES_LIMIT,
.write = mem_cgroup_write,
.read = mem_cgroup_read,
},
{
.name = "failcnt",
.private = RES_FAILCNT,
.read = mem_cgroup_read,
},
{
.name = "force_empty",
.write = mem_force_empty_write,
.read = mem_force_empty_read,
},
{
.name = "stat",
.open = mem_control_stat_open,
},
};
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;
/*
* 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_HIGH_MEMORY))
pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, node);
else
pn = kmalloc(sizeof(*pn), GFP_KERNEL);
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 init_mem_cgroup;
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;
init_mm.mem_cgroup = mem;
} else
mem = kzalloc(sizeof(struct mem_cgroup), GFP_KERNEL);
if (mem == NULL)
return NULL;
res_counter_init(&mem->res);
memset(&mem->info, 0, sizeof(mem->info));
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)
kfree(mem);
return NULL;
}
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);
kfree(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);
if (mem == old_mem)
goto out;
/*
* Only thread group leaders are allowed to migrate, the mm_struct is
* in effect owned by the leader
*/
if (p->tgid != p->pid)
goto out;
css_get(&mem->css);
rcu_assign_pointer(mm->mem_cgroup, mem);
css_put(&old_mem->css);
out:
mmput(mm);
return;
}
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,
};