From 27a7faa0779dd13729196c1a818c294f44bbd1ee Mon Sep 17 00:00:00 2001 From: KAMEZAWA Hiroyuki Date: Wed, 7 Jan 2009 18:07:58 -0800 Subject: memcg: swap cgroup for remembering usage For accounting swap, we need a record per swap entry, at least. This patch adds following function. - swap_cgroup_swapon() .... called from swapon - swap_cgroup_swapoff() ... called at the end of swapoff. - swap_cgroup_record() .... record information of swap entry. - swap_cgroup_lookup() .... lookup information of swap entry. This patch just implements "how to record information". No actual method for limit the usage of swap. These routine uses flat table to record and lookup. "wise" lookup system like radix-tree requires requires memory allocation at new records but swap-out is usually called under memory shortage (or memcg hits limit.) So, I used static allocation. (maybe dynamic allocation is not very hard but it adds additional memory allocation in memory shortage path.) Note1: In this, we use pointer to record information and this means 8bytes per swap entry. I think we can reduce this when we create "id of cgroup" in the range of 0-65535 or 0-255. Reported-by: Daisuke Nishimura Reviewed-by: Daisuke Nishimura Tested-by: Daisuke Nishimura Reported-by: Hugh Dickins Reported-by: Balbir Singh Reported-by: Andrew Morton Signed-off-by: KAMEZAWA Hiroyuki Cc: Pavel Emelianov Cc: Li Zefan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/swapfile.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'mm/swapfile.c') diff --git a/mm/swapfile.c b/mm/swapfile.c index ddc6d92be2cb..1e7a715a3866 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -33,6 +33,7 @@ #include #include #include +#include static DEFINE_SPINLOCK(swap_lock); static unsigned int nr_swapfiles; @@ -1494,6 +1495,9 @@ asmlinkage long sys_swapoff(const char __user * specialfile) spin_unlock(&swap_lock); mutex_unlock(&swapon_mutex); vfree(swap_map); + /* Destroy swap account informatin */ + swap_cgroup_swapoff(type); + inode = mapping->host; if (S_ISBLK(inode->i_mode)) { struct block_device *bdev = I_BDEV(inode); @@ -1811,6 +1815,11 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) } swap_map[page_nr] = SWAP_MAP_BAD; } + + error = swap_cgroup_swapon(type, maxpages); + if (error) + goto bad_swap; + nr_good_pages = swap_header->info.last_page - swap_header->info.nr_badpages - 1 /* header page */; @@ -1882,6 +1891,7 @@ bad_swap: bd_release(bdev); } destroy_swap_extents(p); + swap_cgroup_swapoff(type); bad_swap_2: spin_lock(&swap_lock); p->swap_file = NULL; -- cgit v1.2.3