remarkable-linux/include/linux/memcontrol.h
David Rientjes a63d83f427 oom: badness heuristic rewrite
This a complete rewrite of the oom killer's badness() heuristic which is
used to determine which task to kill in oom conditions.  The goal is to
make it as simple and predictable as possible so the results are better
understood and we end up killing the task which will lead to the most
memory freeing while still respecting the fine-tuning from userspace.

Instead of basing the heuristic on mm->total_vm for each task, the task's
rss and swap space is used instead.  This is a better indication of the
amount of memory that will be freeable if the oom killed task is chosen
and subsequently exits.  This helps specifically in cases where KDE or
GNOME is chosen for oom kill on desktop systems instead of a memory
hogging task.

The baseline for the heuristic is a proportion of memory that each task is
currently using in memory plus swap compared to the amount of "allowable"
memory.  "Allowable," in this sense, means the system-wide resources for
unconstrained oom conditions, the set of mempolicy nodes, the mems
attached to current's cpuset, or a memory controller's limit.  The
proportion is given on a scale of 0 (never kill) to 1000 (always kill),
roughly meaning that if a task has a badness() score of 500 that the task
consumes approximately 50% of allowable memory resident in RAM or in swap
space.

The proportion is always relative to the amount of "allowable" memory and
not the total amount of RAM systemwide so that mempolicies and cpusets may
operate in isolation; they shall not need to know the true size of the
machine on which they are running if they are bound to a specific set of
nodes or mems, respectively.

Root tasks are given 3% extra memory just like __vm_enough_memory()
provides in LSMs.  In the event of two tasks consuming similar amounts of
memory, it is generally better to save root's task.

Because of the change in the badness() heuristic's baseline, it is also
necessary to introduce a new user interface to tune it.  It's not possible
to redefine the meaning of /proc/pid/oom_adj with a new scale since the
ABI cannot be changed for backward compatability.  Instead, a new tunable,
/proc/pid/oom_score_adj, is added that ranges from -1000 to +1000.  It may
be used to polarize the heuristic such that certain tasks are never
considered for oom kill while others may always be considered.  The value
is added directly into the badness() score so a value of -500, for
example, means to discount 50% of its memory consumption in comparison to
other tasks either on the system, bound to the mempolicy, in the cpuset,
or sharing the same memory controller.

/proc/pid/oom_adj is changed so that its meaning is rescaled into the
units used by /proc/pid/oom_score_adj, and vice versa.  Changing one of
these per-task tunables will rescale the value of the other to an
equivalent meaning.  Although /proc/pid/oom_adj was originally defined as
a bitshift on the badness score, it now shares the same linear growth as
/proc/pid/oom_score_adj but with different granularity.  This is required
so the ABI is not broken with userspace applications and allows oom_adj to
be deprecated for future removal.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-09 20:45:02 -07:00

319 lines
8.1 KiB
C

/* memcontrol.h - 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.
*/
#ifndef _LINUX_MEMCONTROL_H
#define _LINUX_MEMCONTROL_H
#include <linux/cgroup.h>
struct mem_cgroup;
struct page_cgroup;
struct page;
struct mm_struct;
extern 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);
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
/*
* All "charge" functions with gfp_mask should use GFP_KERNEL or
* (gfp_mask & GFP_RECLAIM_MASK). In current implementatin, memcg doesn't
* alloc memory but reclaims memory from all available zones. So, "where I want
* memory from" bits of gfp_mask has no meaning. So any bits of that field is
* available but adding a rule is better. charge functions' gfp_mask should
* be set to GFP_KERNEL or gfp_mask & GFP_RECLAIM_MASK for avoiding ambiguous
* codes.
* (Of course, if memcg does memory allocation in future, GFP_KERNEL is sane.)
*/
extern int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask);
/* for swap handling */
extern int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
struct page *page, gfp_t mask, struct mem_cgroup **ptr);
extern void mem_cgroup_commit_charge_swapin(struct page *page,
struct mem_cgroup *ptr);
extern void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *ptr);
extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask);
extern void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru);
extern void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru);
extern void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru);
extern void mem_cgroup_del_lru(struct page *page);
extern void mem_cgroup_move_lists(struct page *page,
enum lru_list from, enum lru_list to);
/* For coalescing uncharge for reducing memcg' overhead*/
extern void mem_cgroup_uncharge_start(void);
extern void mem_cgroup_uncharge_end(void);
extern void mem_cgroup_uncharge_page(struct page *page);
extern void mem_cgroup_uncharge_cache_page(struct page *page);
extern int mem_cgroup_shmem_charge_fallback(struct page *page,
struct mm_struct *mm, gfp_t gfp_mask);
extern void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask);
int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
static inline
int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
{
struct mem_cgroup *mem;
rcu_read_lock();
mem = mem_cgroup_from_task(rcu_dereference((mm)->owner));
rcu_read_unlock();
return cgroup == mem;
}
extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem);
extern int
mem_cgroup_prepare_migration(struct page *page,
struct page *newpage, struct mem_cgroup **ptr);
extern void mem_cgroup_end_migration(struct mem_cgroup *mem,
struct page *oldpage, struct page *newpage);
/*
* For memory reclaim.
*/
int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg);
int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg);
unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
struct zone *zone,
enum lru_list lru);
struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
struct zone *zone);
struct zone_reclaim_stat*
mem_cgroup_get_reclaim_stat_from_page(struct page *page);
extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
struct task_struct *p);
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
extern int do_swap_account;
#endif
static inline bool mem_cgroup_disabled(void)
{
if (mem_cgroup_subsys.disabled)
return true;
return false;
}
void mem_cgroup_update_file_mapped(struct page *page, int val);
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_t gfp_mask, int nid,
int zid);
u64 mem_cgroup_get_limit(struct mem_cgroup *mem);
#else /* CONFIG_CGROUP_MEM_RES_CTLR */
struct mem_cgroup;
static inline int mem_cgroup_newpage_charge(struct page *page,
struct mm_struct *mm, gfp_t gfp_mask)
{
return 0;
}
static inline int mem_cgroup_cache_charge(struct page *page,
struct mm_struct *mm, gfp_t gfp_mask)
{
return 0;
}
static inline int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
struct page *page, gfp_t gfp_mask, struct mem_cgroup **ptr)
{
return 0;
}
static inline void mem_cgroup_commit_charge_swapin(struct page *page,
struct mem_cgroup *ptr)
{
}
static inline void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *ptr)
{
}
static inline void mem_cgroup_uncharge_start(void)
{
}
static inline void mem_cgroup_uncharge_end(void)
{
}
static inline void mem_cgroup_uncharge_page(struct page *page)
{
}
static inline void mem_cgroup_uncharge_cache_page(struct page *page)
{
}
static inline int mem_cgroup_shmem_charge_fallback(struct page *page,
struct mm_struct *mm, gfp_t gfp_mask)
{
return 0;
}
static inline void mem_cgroup_add_lru_list(struct page *page, int lru)
{
}
static inline void mem_cgroup_del_lru_list(struct page *page, int lru)
{
return ;
}
static inline void mem_cgroup_rotate_lru_list(struct page *page, int lru)
{
return ;
}
static inline void mem_cgroup_del_lru(struct page *page)
{
return ;
}
static inline void
mem_cgroup_move_lists(struct page *page, enum lru_list from, enum lru_list to)
{
}
static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
{
return NULL;
}
static inline int mm_match_cgroup(struct mm_struct *mm, struct mem_cgroup *mem)
{
return 1;
}
static inline int task_in_mem_cgroup(struct task_struct *task,
const struct mem_cgroup *mem)
{
return 1;
}
static inline struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem)
{
return NULL;
}
static inline int
mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
struct mem_cgroup **ptr)
{
return 0;
}
static inline void mem_cgroup_end_migration(struct mem_cgroup *mem,
struct page *oldpage,
struct page *newpage)
{
}
static inline int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem)
{
return 0;
}
static inline void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem,
int priority)
{
}
static inline void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,
int priority)
{
}
static inline bool mem_cgroup_disabled(void)
{
return true;
}
static inline int
mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
{
return 1;
}
static inline int
mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg)
{
return 1;
}
static inline unsigned long
mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg, struct zone *zone,
enum lru_list lru)
{
return 0;
}
static inline struct zone_reclaim_stat*
mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, struct zone *zone)
{
return NULL;
}
static inline struct zone_reclaim_stat*
mem_cgroup_get_reclaim_stat_from_page(struct page *page)
{
return NULL;
}
static inline void
mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
{
}
static inline void mem_cgroup_update_file_mapped(struct page *page,
int val)
{
}
static inline
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_t gfp_mask, int nid, int zid)
{
return 0;
}
static inline
u64 mem_cgroup_get_limit(struct mem_cgroup *mem)
{
return 0;
}
#endif /* CONFIG_CGROUP_MEM_CONT */
#endif /* _LINUX_MEMCONTROL_H */