diff options
| author | KAMEZAWA Hiroyuki | 2009-04-02 16:57:45 -0700 |
|---|---|---|
| committer | Linus Torvalds | 2009-04-02 19:04:56 -0700 |
| commit | a3b2d692690aef228e493b1beaafe5364cab3237 (patch) | |
| tree | d3ad99c5370462861a1b918b4136e7bd7ad78e52 /include/linux/page_cgroup.h | |
| parent | 3c776e64660028236313f0e54f3a9945764422df (diff) | |
cgroups: use css id in swap cgroup for saving memory v5
Try to use CSS ID for records in swap_cgroup. By this, on 64bit machine,
size of swap_cgroup goes down to 2 bytes from 8bytes.
This means, when 2GB of swap is equipped, (assume the page size is 4096bytes)
From size of swap_cgroup = 2G/4k * 8 = 4Mbytes.
To size of swap_cgroup = 2G/4k * 2 = 1Mbytes.
Reduction is large. Of course, there are trade-offs. This CSS ID will
add overhead to swap-in/swap-out/swap-free.
But in general,
- swap is a resource which the user tend to avoid use.
- If swap is never used, swap_cgroup area is not used.
- Reading traditional manuals, size of swap should be proportional to
size of memory. Memory size of machine is increasing now.
I think reducing size of swap_cgroup makes sense.
Note:
- ID->CSS lookup routine has no locks, it's under RCU-Read-Side.
- memcg can be obsolete at rmdir() but not freed while refcnt from
swap_cgroup is available.
Changelog v4->v5:
- reworked on to memcg-charge-swapcache-to-proper-memcg.patch
Changlog ->v4:
- fixed not configured case.
- deleted unnecessary comments.
- fixed NULL pointer bug.
- fixed message in dmesg.
[nishimura@mxp.nes.nec.co.jp: css_tryget can be called twice in !PageCgroupUsed case]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: 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>
Diffstat (limited to 'include/linux/page_cgroup.h')
| -rw-r--r-- | include/linux/page_cgroup.h | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h index 602cc1fdee90..7339c7bf7331 100644 --- a/include/linux/page_cgroup.h +++ b/include/linux/page_cgroup.h @@ -91,24 +91,23 @@ static inline void page_cgroup_init(void) #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP #include <linux/swap.h> -extern struct mem_cgroup * -swap_cgroup_record(swp_entry_t ent, struct mem_cgroup *mem); -extern struct mem_cgroup *lookup_swap_cgroup(swp_entry_t ent); +extern unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id); +extern unsigned short lookup_swap_cgroup(swp_entry_t ent); extern int swap_cgroup_swapon(int type, unsigned long max_pages); extern void swap_cgroup_swapoff(int type); #else #include <linux/swap.h> static inline -struct mem_cgroup *swap_cgroup_record(swp_entry_t ent, struct mem_cgroup *mem) +unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id) { - return NULL; + return 0; } static inline -struct mem_cgroup *lookup_swap_cgroup(swp_entry_t ent) +unsigned short lookup_swap_cgroup(swp_entry_t ent) { - return NULL; + return 0; } static inline int |