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authorDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>2010-03-10 15:22:17 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-12 15:52:36 -0800
commit024914477e15ef8b17f271ec47f1bb8a589f0806 (patch)
tree9a6a8b4224c94fcdd1b8c3127b301ee3537f8cc2 /Documentation
parent8033b97c9b5ef063e3f4bf2efe1cd0a22093aaff (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 'Documentation')
-rw-r--r--Documentation/cgroups/memory.txt2
1 files changed, 2 insertions, 0 deletions
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index e726fb0..1f59a1a 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -420,6 +420,8 @@ NOTE2: It is recommended to set the soft limit always below the hard limit,
Users can move charges associated with a task along with task migration, that
is, uncharge task's pages from the old cgroup and charge them to the new cgroup.
+This feature is not supported in !CONFIG_MMU environments because of lack of
+page tables.
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