89c06bd52f
Now, page-stat-per-memcg is recorded into per page_cgroup flag by
duplicating page's status into the flag. The reason is that memcg has a
feature to move a page from a group to another group and we have race
between "move" and "page stat accounting",
Under current logic, assume CPU-A and CPU-B. CPU-A does "move" and CPU-B
does "page stat accounting".
When CPU-A goes 1st,
CPU-A CPU-B
update "struct page" info.
move_lock_mem_cgroup(memcg)
see pc->flags
copy page stat to new group
overwrite pc->mem_cgroup.
move_unlock_mem_cgroup(memcg)
move_lock_mem_cgroup(mem)
set pc->flags
update page stat accounting
move_unlock_mem_cgroup(mem)
stat accounting is guarded by move_lock_mem_cgroup() and "move" logic
(CPU-A) doesn't see changes in "struct page" information.
But it's costly to have the same information both in 'struct page' and
'struct page_cgroup'. And, there is a potential problem.
For example, assume we have PG_dirty accounting in memcg.
PG_..is a flag for struct page.
PCG_ is a flag for struct page_cgroup.
(This is just an example. The same problem can be found in any
kind of page stat accounting.)
CPU-A CPU-B
TestSet PG_dirty
(delay) TestClear PG_dirty
if (TestClear(PCG_dirty))
memcg->nr_dirty--
if (TestSet(PCG_dirty))
memcg->nr_dirty++
Here, memcg->nr_dirty = +1, this is wrong. This race was reported by Greg
Thelen <gthelen@google.com>. Now, only FILE_MAPPED is supported but
fortunately, it's serialized by page table lock and this is not real bug,
_now_,
If this potential problem is caused by having duplicated information in
struct page and struct page_cgroup, we may be able to fix this by using
original 'struct page' information. But we'll have a problem in "move
account"
Assume we use only PG_dirty.
CPU-A CPU-B
TestSet PG_dirty
(delay) move_lock_mem_cgroup()
if (PageDirty(page))
new_memcg->nr_dirty++
pc->mem_cgroup = new_memcg;
move_unlock_mem_cgroup()
move_lock_mem_cgroup()
memcg = pc->mem_cgroup
new_memcg->nr_dirty++
accounting information may be double-counted. This was original reason to
have PCG_xxx flags but it seems PCG_xxx has another problem.
I think we need a bigger lock as
move_lock_mem_cgroup(page)
TestSetPageDirty(page)
update page stats (without any checks)
move_unlock_mem_cgroup(page)
This fixes both of problems and we don't have to duplicate page flag into
page_cgroup. Please note: move_lock_mem_cgroup() is held only when there
are possibility of "account move" under the system. So, in most path,
status update will go without atomic locks.
This patch introduces mem_cgroup_begin_update_page_stat() and
mem_cgroup_end_update_page_stat() both should be called at modifying
'struct page' information if memcg takes care of it. as
mem_cgroup_begin_update_page_stat()
modify page information
mem_cgroup_update_page_stat()
=> never check any 'struct page' info, just update counters.
mem_cgroup_end_update_page_stat().
This patch is slow because we need to call begin_update_page_stat()/
end_update_page_stat() regardless of accounted will be changed or not. A
following patch adds an easy optimization and reduces the cost.
[akpm@linux-foundation.org: s/lock/locked/]
[hughd@google.com: fix deadlock by avoiding stat lock when anon]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Greg Thelen <gthelen@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
450 lines
12 KiB
C
450 lines
12 KiB
C
/* memcontrol.h - Memory Controller
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*
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* Copyright IBM Corporation, 2007
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* Author Balbir Singh <balbir@linux.vnet.ibm.com>
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*
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* Copyright 2007 OpenVZ SWsoft Inc
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* Author: Pavel Emelianov <xemul@openvz.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#ifndef _LINUX_MEMCONTROL_H
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#define _LINUX_MEMCONTROL_H
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#include <linux/cgroup.h>
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#include <linux/vm_event_item.h>
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struct mem_cgroup;
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struct page_cgroup;
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struct page;
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struct mm_struct;
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/* Stats that can be updated by kernel. */
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enum mem_cgroup_page_stat_item {
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MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
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};
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struct mem_cgroup_reclaim_cookie {
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struct zone *zone;
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int priority;
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unsigned int generation;
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};
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#ifdef CONFIG_CGROUP_MEM_RES_CTLR
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/*
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* All "charge" functions with gfp_mask should use GFP_KERNEL or
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* (gfp_mask & GFP_RECLAIM_MASK). In current implementatin, memcg doesn't
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* alloc memory but reclaims memory from all available zones. So, "where I want
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* memory from" bits of gfp_mask has no meaning. So any bits of that field is
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* available but adding a rule is better. charge functions' gfp_mask should
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* be set to GFP_KERNEL or gfp_mask & GFP_RECLAIM_MASK for avoiding ambiguous
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* codes.
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* (Of course, if memcg does memory allocation in future, GFP_KERNEL is sane.)
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*/
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extern int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm,
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gfp_t gfp_mask);
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/* for swap handling */
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extern int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
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struct page *page, gfp_t mask, struct mem_cgroup **memcgp);
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extern void mem_cgroup_commit_charge_swapin(struct page *page,
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struct mem_cgroup *memcg);
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extern void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg);
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extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
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gfp_t gfp_mask);
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struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
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struct lruvec *mem_cgroup_lru_add_list(struct zone *, struct page *,
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enum lru_list);
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void mem_cgroup_lru_del_list(struct page *, enum lru_list);
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void mem_cgroup_lru_del(struct page *);
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struct lruvec *mem_cgroup_lru_move_lists(struct zone *, struct page *,
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enum lru_list, enum lru_list);
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/* For coalescing uncharge for reducing memcg' overhead*/
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extern void mem_cgroup_uncharge_start(void);
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extern void mem_cgroup_uncharge_end(void);
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extern void mem_cgroup_uncharge_page(struct page *page);
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extern void mem_cgroup_uncharge_cache_page(struct page *page);
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extern void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
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int order);
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int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg);
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extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
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extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
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extern struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm);
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extern struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
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extern struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont);
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static inline
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int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
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{
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struct mem_cgroup *memcg;
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rcu_read_lock();
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memcg = mem_cgroup_from_task(rcu_dereference((mm)->owner));
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rcu_read_unlock();
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return cgroup == memcg;
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}
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extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg);
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extern int
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mem_cgroup_prepare_migration(struct page *page,
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struct page *newpage, struct mem_cgroup **memcgp, gfp_t gfp_mask);
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extern void mem_cgroup_end_migration(struct mem_cgroup *memcg,
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struct page *oldpage, struct page *newpage, bool migration_ok);
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struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
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struct mem_cgroup *,
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struct mem_cgroup_reclaim_cookie *);
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void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
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/*
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* For memory reclaim.
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*/
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int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg,
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struct zone *zone);
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int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg,
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struct zone *zone);
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int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
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unsigned long mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg,
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int nid, int zid, unsigned int lrumask);
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struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
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struct zone *zone);
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struct zone_reclaim_stat*
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mem_cgroup_get_reclaim_stat_from_page(struct page *page);
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extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
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struct task_struct *p);
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extern void mem_cgroup_replace_page_cache(struct page *oldpage,
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struct page *newpage);
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#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
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extern int do_swap_account;
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#endif
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static inline bool mem_cgroup_disabled(void)
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{
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if (mem_cgroup_subsys.disabled)
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return true;
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return false;
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}
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void __mem_cgroup_begin_update_page_stat(struct page *page, bool *locked,
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unsigned long *flags);
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static inline void mem_cgroup_begin_update_page_stat(struct page *page,
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bool *locked, unsigned long *flags)
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{
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if (mem_cgroup_disabled())
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return;
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rcu_read_lock();
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*locked = false;
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return __mem_cgroup_begin_update_page_stat(page, locked, flags);
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}
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void __mem_cgroup_end_update_page_stat(struct page *page,
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unsigned long *flags);
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static inline void mem_cgroup_end_update_page_stat(struct page *page,
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bool *locked, unsigned long *flags)
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{
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if (mem_cgroup_disabled())
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return;
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if (*locked)
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__mem_cgroup_end_update_page_stat(page, flags);
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rcu_read_unlock();
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}
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void mem_cgroup_update_page_stat(struct page *page,
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enum mem_cgroup_page_stat_item idx,
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int val);
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static inline void mem_cgroup_inc_page_stat(struct page *page,
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enum mem_cgroup_page_stat_item idx)
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{
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mem_cgroup_update_page_stat(page, idx, 1);
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}
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static inline void mem_cgroup_dec_page_stat(struct page *page,
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enum mem_cgroup_page_stat_item idx)
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{
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mem_cgroup_update_page_stat(page, idx, -1);
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}
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unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
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gfp_t gfp_mask,
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unsigned long *total_scanned);
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u64 mem_cgroup_get_limit(struct mem_cgroup *memcg);
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void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
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#ifdef CONFIG_TRANSPARENT_HUGEPAGE
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void mem_cgroup_split_huge_fixup(struct page *head);
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#endif
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#ifdef CONFIG_DEBUG_VM
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bool mem_cgroup_bad_page_check(struct page *page);
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void mem_cgroup_print_bad_page(struct page *page);
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#endif
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#else /* CONFIG_CGROUP_MEM_RES_CTLR */
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struct mem_cgroup;
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static inline int mem_cgroup_newpage_charge(struct page *page,
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struct mm_struct *mm, gfp_t gfp_mask)
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{
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return 0;
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}
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static inline int mem_cgroup_cache_charge(struct page *page,
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struct mm_struct *mm, gfp_t gfp_mask)
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{
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return 0;
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}
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static inline int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
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struct page *page, gfp_t gfp_mask, struct mem_cgroup **memcgp)
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{
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return 0;
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}
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static inline void mem_cgroup_commit_charge_swapin(struct page *page,
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struct mem_cgroup *memcg)
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{
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}
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static inline void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
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{
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}
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static inline void mem_cgroup_uncharge_start(void)
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{
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}
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static inline void mem_cgroup_uncharge_end(void)
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{
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}
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static inline void mem_cgroup_uncharge_page(struct page *page)
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{
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}
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static inline void mem_cgroup_uncharge_cache_page(struct page *page)
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{
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}
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static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
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struct mem_cgroup *memcg)
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{
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return &zone->lruvec;
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}
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static inline struct lruvec *mem_cgroup_lru_add_list(struct zone *zone,
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struct page *page,
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enum lru_list lru)
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{
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return &zone->lruvec;
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}
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static inline void mem_cgroup_lru_del_list(struct page *page, enum lru_list lru)
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{
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}
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static inline void mem_cgroup_lru_del(struct page *page)
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{
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}
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static inline struct lruvec *mem_cgroup_lru_move_lists(struct zone *zone,
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struct page *page,
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enum lru_list from,
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enum lru_list to)
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{
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return &zone->lruvec;
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}
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static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
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{
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return NULL;
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}
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static inline struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
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{
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return NULL;
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}
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static inline int mm_match_cgroup(struct mm_struct *mm,
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struct mem_cgroup *memcg)
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{
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return 1;
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}
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static inline int task_in_mem_cgroup(struct task_struct *task,
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const struct mem_cgroup *memcg)
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{
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return 1;
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}
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static inline struct cgroup_subsys_state
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*mem_cgroup_css(struct mem_cgroup *memcg)
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{
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return NULL;
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}
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static inline int
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mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
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struct mem_cgroup **memcgp, gfp_t gfp_mask)
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{
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return 0;
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}
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static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg,
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struct page *oldpage, struct page *newpage, bool migration_ok)
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{
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}
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static inline struct mem_cgroup *
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mem_cgroup_iter(struct mem_cgroup *root,
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struct mem_cgroup *prev,
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struct mem_cgroup_reclaim_cookie *reclaim)
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{
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return NULL;
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}
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static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
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struct mem_cgroup *prev)
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{
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}
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static inline bool mem_cgroup_disabled(void)
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{
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return true;
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}
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static inline int
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mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)
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{
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return 1;
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}
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static inline int
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mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone)
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{
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return 1;
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}
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static inline unsigned long
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mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
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unsigned int lru_mask)
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{
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return 0;
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}
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static inline struct zone_reclaim_stat*
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mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, struct zone *zone)
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{
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return NULL;
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}
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static inline struct zone_reclaim_stat*
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mem_cgroup_get_reclaim_stat_from_page(struct page *page)
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{
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return NULL;
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}
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static inline void
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mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
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{
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}
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static inline void mem_cgroup_begin_update_page_stat(struct page *page,
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bool *locked, unsigned long *flags)
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{
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}
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static inline void mem_cgroup_end_update_page_stat(struct page *page,
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bool *locked, unsigned long *flags)
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{
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}
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static inline void mem_cgroup_inc_page_stat(struct page *page,
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enum mem_cgroup_page_stat_item idx)
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{
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}
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static inline void mem_cgroup_dec_page_stat(struct page *page,
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enum mem_cgroup_page_stat_item idx)
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{
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}
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static inline
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unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
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gfp_t gfp_mask,
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unsigned long *total_scanned)
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{
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return 0;
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}
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static inline
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u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
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{
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return 0;
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}
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static inline void mem_cgroup_split_huge_fixup(struct page *head)
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{
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}
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static inline
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void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
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{
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}
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static inline void mem_cgroup_replace_page_cache(struct page *oldpage,
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struct page *newpage)
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{
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}
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#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
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#if !defined(CONFIG_CGROUP_MEM_RES_CTLR) || !defined(CONFIG_DEBUG_VM)
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static inline bool
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mem_cgroup_bad_page_check(struct page *page)
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{
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return false;
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}
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static inline void
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mem_cgroup_print_bad_page(struct page *page)
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{
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}
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#endif
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enum {
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UNDER_LIMIT,
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SOFT_LIMIT,
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OVER_LIMIT,
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};
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struct sock;
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#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
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void sock_update_memcg(struct sock *sk);
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void sock_release_memcg(struct sock *sk);
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|
#else
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static inline void sock_update_memcg(struct sock *sk)
|
|
{
|
|
}
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|
static inline void sock_release_memcg(struct sock *sk)
|
|
{
|
|
}
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|
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
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#endif /* _LINUX_MEMCONTROL_H */
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|
|