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author | Vladimir Davydov <vdavydov@parallels.com> | 2015-02-13 01:59:38 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-13 05:54:10 +0300 |
commit | 2788cf0c401c268b4819c5407493a8769b7007aa (patch) | |
tree | 863ea244d6908bd6e8149e6cd81270389a9426a8 /include/linux | |
parent | 3f97b163207c67a3b35931494ad3db1de66356f0 (diff) | |
download | linux-2788cf0c401c268b4819c5407493a8769b7007aa.tar.xz |
memcg: reparent list_lrus and free kmemcg_id on css offline
Now, the only reason to keep kmemcg_id till css free is list_lru, which
uses it to distribute elements between per-memcg lists. However, it can
be easily sorted out - we only need to change kmemcg_id of an offline
cgroup to its parent's id, making further list_lru_add()'s add elements to
the parent's list, and then move all elements from the offline cgroup's
list to the one of its parent. It will work, because a racing
list_lru_del() does not need to know the list it is deleting the element
from. It can decrement the wrong nr_items counter though, but the ongoing
reparenting will fix it. After list_lru reparenting is done we are free
to release kmemcg_id saving a valuable slot in a per-memcg array for new
cgroups.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/list_lru.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h index 7edf9c9ab9eb..2a6b9947aaa3 100644 --- a/include/linux/list_lru.h +++ b/include/linux/list_lru.h @@ -26,7 +26,7 @@ enum lru_status { struct list_lru_one { struct list_head list; - /* kept as signed so we can catch imbalance bugs */ + /* may become negative during memcg reparenting */ long nr_items; }; @@ -62,6 +62,7 @@ int __list_lru_init(struct list_lru *lru, bool memcg_aware, #define list_lru_init_memcg(lru) __list_lru_init((lru), true, NULL) int memcg_update_all_list_lrus(int num_memcgs); +void memcg_drain_all_list_lrus(int src_idx, int dst_idx); /** * list_lru_add: add an element to the lru list's tail |