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memcg: allocate all page_cgroup at boot

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Allocate all page_cgroup at boot and remove page_cgroup poitner from
struct page.  This patch adds an interface as

 struct page_cgroup *lookup_page_cgroup(struct page*)

All FLATMEM/DISCONTIGMEM/SPARSEMEM  and MEMORY_HOTPLUG is supported.

Remove page_cgroup pointer reduces the amount of memory by
 - 4 bytes per PAGE_SIZE.
 - 8 bytes per PAGE_SIZE
if memory controller is disabled. (even if configured.)

On usual 8GB x86-32 server, this saves 8MB of NORMAL_ZONE memory.
On my x86-64 server with 48GB of memory, this saves 96MB of memory.
I think this reduction makes sense.

By pre-allocation, kmalloc/kfree in charge/uncharge are removed.
This means
  - we're not necessary to be afraid of kmalloc faiulre.
    (this can happen because of gfp_mask type.)
  - we can avoid calling kmalloc/kfree.
  - we can avoid allocating tons of small objects which can be fragmented.
  - we can know what amount of memory will be used for this extra-lru handling.

I added printk message as

	"allocated %ld bytes of page_cgroup"
        "please try cgroup_disable=memory option if you don't want"

maybe enough informative for users.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki 2008-10-18 20:28:16 -07:00 • committed by Linus Torvalds
parent c05555b572
commit 52d4b9ac0b
8 changed files with 438 additions and 194 deletions
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103
include/linux/page_cgroup.h Normal file
View file

@ -0,0 +1,103 @@
#ifndef __LINUX_PAGE_CGROUP_H
#define __LINUX_PAGE_CGROUP_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;
struct page *page;
struct list_head lru; /* per cgroup LRU list */
};
void __init pgdat_page_cgroup_init(struct pglist_data *pgdat);
void __init page_cgroup_init(void);
struct page_cgroup *lookup_page_cgroup(struct page *page);
enum {
/* flags for mem_cgroup */
PCG_LOCK, /* page cgroup is locked */
PCG_CACHE, /* charged as cache */
PCG_USED, /* this object is in use. */
/* flags for LRU placement */
PCG_ACTIVE, /* page is active in this cgroup */
PCG_FILE, /* page is file system backed */
PCG_UNEVICTABLE, /* page is unevictableable */
};
#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); }
/* Cache flag is set only once (at allocation) */
TESTPCGFLAG(Cache, CACHE)
TESTPCGFLAG(Used, USED)
CLEARPCGFLAG(Used, USED)
/* LRU management flags (from global-lru definition) */
TESTPCGFLAG(File, FILE)
SETPCGFLAG(File, FILE)
CLEARPCGFLAG(File, FILE)
TESTPCGFLAG(Active, ACTIVE)
SETPCGFLAG(Active, ACTIVE)
CLEARPCGFLAG(Active, ACTIVE)
TESTPCGFLAG(Unevictable, UNEVICTABLE)
SETPCGFLAG(Unevictable, UNEVICTABLE)
CLEARPCGFLAG(Unevictable, UNEVICTABLE)
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);
}
static inline void lock_page_cgroup(struct page_cgroup *pc)
{
bit_spin_lock(PCG_LOCK, &pc->flags);
}
static inline int trylock_page_cgroup(struct page_cgroup *pc)
{
return bit_spin_trylock(PCG_LOCK, &pc->flags);
}
static inline void unlock_page_cgroup(struct page_cgroup *pc)
{
bit_spin_unlock(PCG_LOCK, &pc->flags);
}
#else /* CONFIG_CGROUP_MEM_RES_CTLR */
struct page_cgroup;
static inline void pgdat_page_cgroup_init(struct pglist_data *pgdat)
{
}
static inline struct page_cgroup *lookup_page_cgroup(struct page *page)
{
return NULL;
}
#endif
#endif