alistair23-linux/include/linux/page_cgroup.h
KAMEZAWA Hiroyuki 38c5d72f3e memcg: simplify LRU handling by new rule
Now, at LRU handling, memory cgroup needs to do complicated works to see
valid pc->mem_cgroup, which may be overwritten.

This patch is for relaxing the protocol. This patch guarantees
   - when pc->mem_cgroup is overwritten, page must not be on LRU.

By this, LRU routine can believe pc->mem_cgroup and don't need to check
bits on pc->flags.  This new rule may adds small overheads to swapin.  But
in most case, lru handling gets faster.

After this patch, PCG_ACCT_LRU bit is obsolete and removed.

[akpm@linux-foundation.org: remove unneeded VM_BUG_ON(), restore hannes's christmas tree]
[akpm@linux-foundation.org: clean up code comment]
[hughd@google.com: fix NULL mem_cgroup_try_charge]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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>
2012-01-12 20:13:07 -08:00

177 lines
4.4 KiB
C

#ifndef __LINUX_PAGE_CGROUP_H
#define __LINUX_PAGE_CGROUP_H
enum {
/* flags for mem_cgroup */
PCG_LOCK, /* Lock for pc->mem_cgroup and following bits. */
PCG_CACHE, /* charged as cache */
PCG_USED, /* this object is in use. */
PCG_MIGRATION, /* under page migration */
/* flags for mem_cgroup and file and I/O status */
PCG_MOVE_LOCK, /* For race between move_account v.s. following bits */
PCG_FILE_MAPPED, /* page is accounted as "mapped" */
__NR_PCG_FLAGS,
};
#ifndef __GENERATING_BOUNDS_H
#include <generated/bounds.h>
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
#include <linux/bit_spinlock.h>
/*
* Page Cgroup can be considered as an extended mem_map.
* A page_cgroup page is associated with every page descriptor. The
* page_cgroup helps us identify information about the cgroup
* All page cgroups are allocated at boot or memory hotplug event,
* then the page cgroup for pfn always exists.
*/
struct page_cgroup {
unsigned long flags;
struct mem_cgroup *mem_cgroup;
};
void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat);
#ifdef CONFIG_SPARSEMEM
static inline void __init page_cgroup_init_flatmem(void)
{
}
extern void __init page_cgroup_init(void);
#else
void __init page_cgroup_init_flatmem(void);
static inline void __init page_cgroup_init(void)
{
}
#endif
struct page_cgroup *lookup_page_cgroup(struct page *page);
struct page *lookup_cgroup_page(struct page_cgroup *pc);
#define TESTPCGFLAG(uname, lname) \
static inline int PageCgroup##uname(struct page_cgroup *pc) \
{ return test_bit(PCG_##lname, &pc->flags); }
#define SETPCGFLAG(uname, lname) \
static inline void SetPageCgroup##uname(struct page_cgroup *pc)\
{ set_bit(PCG_##lname, &pc->flags); }
#define CLEARPCGFLAG(uname, lname) \
static inline void ClearPageCgroup##uname(struct page_cgroup *pc) \
{ clear_bit(PCG_##lname, &pc->flags); }
#define TESTCLEARPCGFLAG(uname, lname) \
static inline int TestClearPageCgroup##uname(struct page_cgroup *pc) \
{ return test_and_clear_bit(PCG_##lname, &pc->flags); }
/* Cache flag is set only once (at allocation) */
TESTPCGFLAG(Cache, CACHE)
CLEARPCGFLAG(Cache, CACHE)
SETPCGFLAG(Cache, CACHE)
TESTPCGFLAG(Used, USED)
CLEARPCGFLAG(Used, USED)
SETPCGFLAG(Used, USED)
SETPCGFLAG(FileMapped, FILE_MAPPED)
CLEARPCGFLAG(FileMapped, FILE_MAPPED)
TESTPCGFLAG(FileMapped, FILE_MAPPED)
SETPCGFLAG(Migration, MIGRATION)
CLEARPCGFLAG(Migration, MIGRATION)
TESTPCGFLAG(Migration, MIGRATION)
static inline void lock_page_cgroup(struct page_cgroup *pc)
{
/*
* Don't take this lock in IRQ context.
* This lock is for pc->mem_cgroup, USED, CACHE, MIGRATION
*/
bit_spin_lock(PCG_LOCK, &pc->flags);
}
static inline void unlock_page_cgroup(struct page_cgroup *pc)
{
bit_spin_unlock(PCG_LOCK, &pc->flags);
}
static inline void move_lock_page_cgroup(struct page_cgroup *pc,
unsigned long *flags)
{
/*
* We know updates to pc->flags of page cache's stats are from both of
* usual context or IRQ context. Disable IRQ to avoid deadlock.
*/
local_irq_save(*flags);
bit_spin_lock(PCG_MOVE_LOCK, &pc->flags);
}
static inline void move_unlock_page_cgroup(struct page_cgroup *pc,
unsigned long *flags)
{
bit_spin_unlock(PCG_MOVE_LOCK, &pc->flags);
local_irq_restore(*flags);
}
#else /* CONFIG_CGROUP_MEM_RES_CTLR */
struct page_cgroup;
static inline void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
{
}
static inline struct page_cgroup *lookup_page_cgroup(struct page *page)
{
return NULL;
}
static inline void page_cgroup_init(void)
{
}
static inline void __init page_cgroup_init_flatmem(void)
{
}
#endif /* CONFIG_CGROUP_MEM_RES_CTLR */
#include <linux/swap.h>
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
extern unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
unsigned short old, unsigned short new);
extern unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id);
extern unsigned short lookup_swap_cgroup_id(swp_entry_t ent);
extern int swap_cgroup_swapon(int type, unsigned long max_pages);
extern void swap_cgroup_swapoff(int type);
#else
static inline
unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
{
return 0;
}
static inline
unsigned short lookup_swap_cgroup_id(swp_entry_t ent)
{
return 0;
}
static inline int
swap_cgroup_swapon(int type, unsigned long max_pages)
{
return 0;
}
static inline void swap_cgroup_swapoff(int type)
{
return;
}
#endif /* CONFIG_CGROUP_MEM_RES_CTLR_SWAP */
#endif /* !__GENERATING_BOUNDS_H */
#endif /* __LINUX_PAGE_CGROUP_H */