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author | Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> | 2010-03-10 15:22:17 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-03-12 15:52:36 -0800 |
commit | 024914477e15ef8b17f271ec47f1bb8a589f0806 (patch) | |
tree | 9a6a8b4224c94fcdd1b8c3127b301ee3537f8cc2 /mm/swapfile.c | |
parent | 8033b97c9b5ef063e3f4bf2efe1cd0a22093aaff (diff) | |
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memcg: move charges of anonymous swap
This patch is another core part of this move-charge-at-task-migration
feature. It enables moving charges of anonymous swaps.
To move the charge of swap, we need to exchange swap_cgroup's record.
In current implementation, swap_cgroup's record is protected by:
- page lock: if the entry is on swap cache.
- swap_lock: if the entry is not on swap cache.
This works well in usual swap-in/out activity.
But this behavior make the feature of moving swap charge check many
conditions to exchange swap_cgroup's record safely.
So I changed modification of swap_cgroup's recored(swap_cgroup_record())
to use xchg, and define a new function to cmpxchg swap_cgroup's record.
This patch also enables moving charge of non pte_present but not uncharged
swap caches, which can be exist on swap-out path, by getting the target
pages via find_get_page() as do_mincore() does.
[kosaki.motohiro@jp.fujitsu.com: fix ia64 build]
[akpm@linux-foundation.org: fix typos]
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swapfile.c')
-rw-r--r-- | mm/swapfile.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index 84374d8..6cd0a8f 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -723,6 +723,37 @@ int free_swap_and_cache(swp_entry_t entry) return p != NULL; } +#ifdef CONFIG_CGROUP_MEM_RES_CTLR +/** + * mem_cgroup_count_swap_user - count the user of a swap entry + * @ent: the swap entry to be checked + * @pagep: the pointer for the swap cache page of the entry to be stored + * + * Returns the number of the user of the swap entry. The number is valid only + * for swaps of anonymous pages. + * If the entry is found on swap cache, the page is stored to pagep with + * refcount of it being incremented. + */ +int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep) +{ + struct page *page; + struct swap_info_struct *p; + int count = 0; + + page = find_get_page(&swapper_space, ent.val); + if (page) + count += page_mapcount(page); + p = swap_info_get(ent); + if (p) { + count += swap_count(p->swap_map[swp_offset(ent)]); + spin_unlock(&swap_lock); + } + + *pagep = page; + return count; +} +#endif + #ifdef CONFIG_HIBERNATION /* * Find the swap type that corresponds to given device (if any). |