android_kernel_oneplus_msm8998/include/linux/memcontrol.h
Vladimir Davydov bd67314586 memcg, slab: simplify synchronization scheme
At present, we have the following mutexes protecting data related to per
memcg kmem caches:

 - slab_mutex.  This one is held during the whole kmem cache creation
   and destruction paths.  We also take it when updating per root cache
   memcg_caches arrays (see memcg_update_all_caches).  As a result, taking
   it guarantees there will be no changes to any kmem cache (including per
   memcg).  Why do we need something else then?  The point is it is
   private to slab implementation and has some internal dependencies with
   other mutexes (get_online_cpus).  So we just don't want to rely upon it
   and prefer to introduce additional mutexes instead.

 - activate_kmem_mutex.  Initially it was added to synchronize
   initializing kmem limit (memcg_activate_kmem).  However, since we can
   grow per root cache memcg_caches arrays only on kmem limit
   initialization (see memcg_update_all_caches), we also employ it to
   protect against memcg_caches arrays relocation (e.g.  see
   __kmem_cache_destroy_memcg_children).

 - We have a convention not to take slab_mutex in memcontrol.c, but we
   want to walk over per memcg memcg_slab_caches lists there (e.g.  for
   destroying all memcg caches on offline).  So we have per memcg
   slab_caches_mutex's protecting those lists.

The mutexes are taken in the following order:

   activate_kmem_mutex -> slab_mutex -> memcg::slab_caches_mutex

Such a syncrhonization scheme has a number of flaws, for instance:

 - We can't call kmem_cache_{destroy,shrink} while walking over a
   memcg::memcg_slab_caches list due to locking order.  As a result, in
   mem_cgroup_destroy_all_caches we schedule the
   memcg_cache_params::destroy work shrinking and destroying the cache.

 - We don't have a mutex to synchronize per memcg caches destruction
   between memcg offline (mem_cgroup_destroy_all_caches) and root cache
   destruction (__kmem_cache_destroy_memcg_children).  Currently we just
   don't bother about it.

This patch simplifies it by substituting per memcg slab_caches_mutex's
with the global memcg_slab_mutex.  It will be held whenever a new per
memcg cache is created or destroyed, so it protects per root cache
memcg_caches arrays and per memcg memcg_slab_caches lists.  The locking
order is following:

   activate_kmem_mutex -> memcg_slab_mutex -> slab_mutex

This allows us to call kmem_cache_{create,shrink,destroy} under the
memcg_slab_mutex.  As a result, we don't need memcg_cache_params::destroy
work any more - we can simply destroy caches while iterating over a per
memcg slab caches list.

Also using the global mutex simplifies synchronization between concurrent
per memcg caches creation/destruction, e.g.  mem_cgroup_destroy_all_caches
vs __kmem_cache_destroy_memcg_children.

The downside of this is that we substitute per-memcg slab_caches_mutex's
with a hummer-like global mutex, but since we already take either the
slab_mutex or the cgroup_mutex along with a memcg::slab_caches_mutex, it
shouldn't hurt concurrency a lot.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:54:01 -07:00

648 lines
17 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>
#include <linux/vm_event_item.h>
#include <linux/hardirq.h>
#include <linux/jump_label.h>
struct mem_cgroup;
struct page_cgroup;
struct page;
struct mm_struct;
struct kmem_cache;
/*
* The corresponding mem_cgroup_stat_names is defined in mm/memcontrol.c,
* These two lists should keep in accord with each other.
*/
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 anon rss */
MEM_CGROUP_STAT_RSS_HUGE, /* # of pages charged as anon huge */
MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
MEM_CGROUP_STAT_WRITEBACK, /* # of pages under writeback */
MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
MEM_CGROUP_STAT_NSTATS,
};
struct mem_cgroup_reclaim_cookie {
struct zone *zone;
int priority;
unsigned int generation;
};
#ifdef CONFIG_MEMCG
/*
* 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_charge_anon(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 **memcgp);
extern void mem_cgroup_commit_charge_swapin(struct page *page,
struct mem_cgroup *memcg);
extern void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg);
extern int mem_cgroup_charge_file(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask);
struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *);
/* 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);
bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
struct mem_cgroup *memcg);
bool task_in_mem_cgroup(struct task_struct *task,
const struct mem_cgroup *memcg);
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);
extern struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
extern struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css);
static inline
bool mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *memcg)
{
struct mem_cgroup *task_memcg;
bool match;
rcu_read_lock();
task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
match = __mem_cgroup_same_or_subtree(memcg, task_memcg);
rcu_read_unlock();
return match;
}
extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg);
extern void
mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
struct mem_cgroup **memcgp);
extern void mem_cgroup_end_migration(struct mem_cgroup *memcg,
struct page *oldpage, struct page *newpage, bool migration_ok);
struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
struct mem_cgroup *,
struct mem_cgroup_reclaim_cookie *);
void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
/*
* For memory reclaim.
*/
int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec);
int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list);
void mem_cgroup_update_lru_size(struct lruvec *, enum lru_list, int);
extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
struct task_struct *p);
extern void mem_cgroup_replace_page_cache(struct page *oldpage,
struct page *newpage);
static inline void mem_cgroup_oom_enable(void)
{
WARN_ON(current->memcg_oom.may_oom);
current->memcg_oom.may_oom = 1;
}
static inline void mem_cgroup_oom_disable(void)
{
WARN_ON(!current->memcg_oom.may_oom);
current->memcg_oom.may_oom = 0;
}
static inline bool task_in_memcg_oom(struct task_struct *p)
{
return p->memcg_oom.memcg;
}
bool mem_cgroup_oom_synchronize(bool wait);
#ifdef CONFIG_MEMCG_SWAP
extern int do_swap_account;
#endif
static inline bool mem_cgroup_disabled(void)
{
if (memory_cgrp_subsys.disabled)
return true;
return false;
}
void __mem_cgroup_begin_update_page_stat(struct page *page, bool *locked,
unsigned long *flags);
extern atomic_t memcg_moving;
static inline void mem_cgroup_begin_update_page_stat(struct page *page,
bool *locked, unsigned long *flags)
{
if (mem_cgroup_disabled())
return;
rcu_read_lock();
*locked = false;
if (atomic_read(&memcg_moving))
__mem_cgroup_begin_update_page_stat(page, locked, flags);
}
void __mem_cgroup_end_update_page_stat(struct page *page,
unsigned long *flags);
static inline void mem_cgroup_end_update_page_stat(struct page *page,
bool *locked, unsigned long *flags)
{
if (mem_cgroup_disabled())
return;
if (*locked)
__mem_cgroup_end_update_page_stat(page, flags);
rcu_read_unlock();
}
void mem_cgroup_update_page_stat(struct page *page,
enum mem_cgroup_stat_index idx,
int val);
static inline void mem_cgroup_inc_page_stat(struct page *page,
enum mem_cgroup_stat_index idx)
{
mem_cgroup_update_page_stat(page, idx, 1);
}
static inline void mem_cgroup_dec_page_stat(struct page *page,
enum mem_cgroup_stat_index idx)
{
mem_cgroup_update_page_stat(page, idx, -1);
}
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_t gfp_mask,
unsigned long *total_scanned);
void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,
enum vm_event_item idx)
{
if (mem_cgroup_disabled())
return;
__mem_cgroup_count_vm_event(mm, idx);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void mem_cgroup_split_huge_fixup(struct page *head);
#endif
#ifdef CONFIG_DEBUG_VM
bool mem_cgroup_bad_page_check(struct page *page);
void mem_cgroup_print_bad_page(struct page *page);
#endif
#else /* CONFIG_MEMCG */
struct mem_cgroup;
static inline int mem_cgroup_charge_anon(struct page *page,
struct mm_struct *mm, gfp_t gfp_mask)
{
return 0;
}
static inline int mem_cgroup_charge_file(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 **memcgp)
{
return 0;
}
static inline void mem_cgroup_commit_charge_swapin(struct page *page,
struct mem_cgroup *memcg)
{
}
static inline void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
{
}
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 struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
struct mem_cgroup *memcg)
{
return &zone->lruvec;
}
static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
struct zone *zone)
{
return &zone->lruvec;
}
static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
{
return NULL;
}
static inline bool mm_match_cgroup(struct mm_struct *mm,
struct mem_cgroup *memcg)
{
return true;
}
static inline bool task_in_mem_cgroup(struct task_struct *task,
const struct mem_cgroup *memcg)
{
return true;
}
static inline struct cgroup_subsys_state
*mem_cgroup_css(struct mem_cgroup *memcg)
{
return NULL;
}
static inline void
mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
struct mem_cgroup **memcgp)
{
}
static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg,
struct page *oldpage, struct page *newpage, bool migration_ok)
{
}
static inline struct mem_cgroup *
mem_cgroup_iter(struct mem_cgroup *root,
struct mem_cgroup *prev,
struct mem_cgroup_reclaim_cookie *reclaim)
{
return NULL;
}
static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
struct mem_cgroup *prev)
{
}
static inline bool mem_cgroup_disabled(void)
{
return true;
}
static inline int
mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
{
return 1;
}
static inline unsigned long
mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
{
return 0;
}
static inline void
mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
int increment)
{
}
static inline void
mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
{
}
static inline void mem_cgroup_begin_update_page_stat(struct page *page,
bool *locked, unsigned long *flags)
{
}
static inline void mem_cgroup_end_update_page_stat(struct page *page,
bool *locked, unsigned long *flags)
{
}
static inline void mem_cgroup_oom_enable(void)
{
}
static inline void mem_cgroup_oom_disable(void)
{
}
static inline bool task_in_memcg_oom(struct task_struct *p)
{
return false;
}
static inline bool mem_cgroup_oom_synchronize(bool wait)
{
return false;
}
static inline void mem_cgroup_inc_page_stat(struct page *page,
enum mem_cgroup_stat_index idx)
{
}
static inline void mem_cgroup_dec_page_stat(struct page *page,
enum mem_cgroup_stat_index idx)
{
}
static inline
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_t gfp_mask,
unsigned long *total_scanned)
{
return 0;
}
static inline void mem_cgroup_split_huge_fixup(struct page *head)
{
}
static inline
void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
{
}
static inline void mem_cgroup_replace_page_cache(struct page *oldpage,
struct page *newpage)
{
}
#endif /* CONFIG_MEMCG */
#if !defined(CONFIG_MEMCG) || !defined(CONFIG_DEBUG_VM)
static inline bool
mem_cgroup_bad_page_check(struct page *page)
{
return false;
}
static inline void
mem_cgroup_print_bad_page(struct page *page)
{
}
#endif
enum {
UNDER_LIMIT,
SOFT_LIMIT,
OVER_LIMIT,
};
struct sock;
#if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
void sock_update_memcg(struct sock *sk);
void sock_release_memcg(struct sock *sk);
#else
static inline void sock_update_memcg(struct sock *sk)
{
}
static inline void sock_release_memcg(struct sock *sk)
{
}
#endif /* CONFIG_INET && CONFIG_MEMCG_KMEM */
#ifdef CONFIG_MEMCG_KMEM
extern struct static_key memcg_kmem_enabled_key;
extern int memcg_limited_groups_array_size;
/*
* Helper macro to loop through all memcg-specific caches. Callers must still
* check if the cache is valid (it is either valid or NULL).
* the slab_mutex must be held when looping through those caches
*/
#define for_each_memcg_cache_index(_idx) \
for ((_idx) = 0; (_idx) < memcg_limited_groups_array_size; (_idx)++)
static inline bool memcg_kmem_enabled(void)
{
return static_key_false(&memcg_kmem_enabled_key);
}
/*
* In general, we'll do everything in our power to not incur in any overhead
* for non-memcg users for the kmem functions. Not even a function call, if we
* can avoid it.
*
* Therefore, we'll inline all those functions so that in the best case, we'll
* see that kmemcg is off for everybody and proceed quickly. If it is on,
* we'll still do most of the flag checking inline. We check a lot of
* conditions, but because they are pretty simple, they are expected to be
* fast.
*/
bool __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg,
int order);
void __memcg_kmem_commit_charge(struct page *page,
struct mem_cgroup *memcg, int order);
void __memcg_kmem_uncharge_pages(struct page *page, int order);
int memcg_cache_id(struct mem_cgroup *memcg);
char *memcg_create_cache_name(struct mem_cgroup *memcg,
struct kmem_cache *root_cache);
int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
struct kmem_cache *root_cache);
void memcg_free_cache_params(struct kmem_cache *s);
int memcg_update_cache_size(struct kmem_cache *s, int num_groups);
void memcg_update_array_size(int num_groups);
struct kmem_cache *
__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp);
int __memcg_charge_slab(struct kmem_cache *cachep, gfp_t gfp, int order);
void __memcg_uncharge_slab(struct kmem_cache *cachep, int order);
int __kmem_cache_destroy_memcg_children(struct kmem_cache *s);
/**
* memcg_kmem_newpage_charge: verify if a new kmem allocation is allowed.
* @gfp: the gfp allocation flags.
* @memcg: a pointer to the memcg this was charged against.
* @order: allocation order.
*
* returns true if the memcg where the current task belongs can hold this
* allocation.
*
* We return true automatically if this allocation is not to be accounted to
* any memcg.
*/
static inline bool
memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
{
if (!memcg_kmem_enabled())
return true;
/*
* __GFP_NOFAIL allocations will move on even if charging is not
* possible. Therefore we don't even try, and have this allocation
* unaccounted. We could in theory charge it with
* res_counter_charge_nofail, but we hope those allocations are rare,
* and won't be worth the trouble.
*/
if (gfp & __GFP_NOFAIL)
return true;
if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
return true;
/* If the test is dying, just let it go. */
if (unlikely(fatal_signal_pending(current)))
return true;
return __memcg_kmem_newpage_charge(gfp, memcg, order);
}
/**
* memcg_kmem_uncharge_pages: uncharge pages from memcg
* @page: pointer to struct page being freed
* @order: allocation order.
*
* there is no need to specify memcg here, since it is embedded in page_cgroup
*/
static inline void
memcg_kmem_uncharge_pages(struct page *page, int order)
{
if (memcg_kmem_enabled())
__memcg_kmem_uncharge_pages(page, order);
}
/**
* memcg_kmem_commit_charge: embeds correct memcg in a page
* @page: pointer to struct page recently allocated
* @memcg: the memcg structure we charged against
* @order: allocation order.
*
* Needs to be called after memcg_kmem_newpage_charge, regardless of success or
* failure of the allocation. if @page is NULL, this function will revert the
* charges. Otherwise, it will commit the memcg given by @memcg to the
* corresponding page_cgroup.
*/
static inline void
memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
{
if (memcg_kmem_enabled() && memcg)
__memcg_kmem_commit_charge(page, memcg, order);
}
/**
* memcg_kmem_get_cache: selects the correct per-memcg cache for allocation
* @cachep: the original global kmem cache
* @gfp: allocation flags.
*
* All memory allocated from a per-memcg cache is charged to the owner memcg.
*/
static __always_inline struct kmem_cache *
memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
{
if (!memcg_kmem_enabled())
return cachep;
if (gfp & __GFP_NOFAIL)
return cachep;
if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
return cachep;
if (unlikely(fatal_signal_pending(current)))
return cachep;
return __memcg_kmem_get_cache(cachep, gfp);
}
#else
#define for_each_memcg_cache_index(_idx) \
for (; NULL; )
static inline bool memcg_kmem_enabled(void)
{
return false;
}
static inline bool
memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
{
return true;
}
static inline void memcg_kmem_uncharge_pages(struct page *page, int order)
{
}
static inline void
memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
{
}
static inline int memcg_cache_id(struct mem_cgroup *memcg)
{
return -1;
}
static inline int memcg_alloc_cache_params(struct mem_cgroup *memcg,
struct kmem_cache *s, struct kmem_cache *root_cache)
{
return 0;
}
static inline void memcg_free_cache_params(struct kmem_cache *s)
{
}
static inline struct kmem_cache *
memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
{
return cachep;
}
#endif /* CONFIG_MEMCG_KMEM */
#endif /* _LINUX_MEMCONTROL_H */