The commit is pushed to "branch-rh7-3.10.0-1160.90.1.vz7.200.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-1160.90.1.vz7.200.4
------>
commit 15d6023b570d8f32f9c41b7add01cd2c7ec3bd0d
Author: Qian Cai <c...@lca.pw>
Date: Wed Jul 5 14:39:51 2023 +0800
ms/mm/memcontrol.c: fix a -Wunused-function warning
mem_cgroup_id_get() was introduced in commit 73f576c04b94 ("mm:memcontrol:
fix cgroup creation failure after many small jobs").
Later, it no longer has any user since the commits,
1f47b61fb407 ("mm: memcontrol: fix swap counter leak on swapout from
offline cgroup")
58fa2a5512d9 ("mm: memcontrol: add sanity checks for memcg->id.ref on
get/put")
so safe to remove it.
Link: http://lkml.kernel.org/r/1568648453-5482-1-git-send-email-...@lca.pw
Signed-off-by: Qian Cai <c...@lca.pw>
Acked-by: Michal Hocko <mho...@suse.com>
Cc: Johannes Weiner <han...@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov....@gmail.com>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
https://jira.vzint.dev/browse/PSBM-147036
(cherry picked from commit 4d0e3230a56a75bf26d74b3f4b6cb05a0e9fae60)
Signed-off-by: Pavel Tikhomirov <ptikhomi...@virtuozzo.com>
=================
Patchset description:
memcg: release id when offlinging cgroup
We see that container user can deplete memory cgroup ids on the system
(64k) and prevent further memory cgroup creation. In crash collected by
our customer in such a situation we see that mem_cgroup_idr is full of
cgroups from one container with same exact path (cgroup of docker
service), cgroups are not released because they have kmem charges, this
kmem charge is for a tmpfs dentry allocated from this cgroup. (And on
vz7 kernel it seems that such a dentry is only released after umounting
tmpfs or removing the corresponding file from tmpfs.)
So there is a valid way to hold kmem cgroup for a long time. Similar
thing was mentioned in mainstream with page cache holding kmem cgroup
for a long time. And they proposed a way to deal with it - just release
cgroup id early so that one can allocate new cgroups immediately.
Reproduce:
https://git.vzint.dev/users/ptikhomirov/repos/helpers/browse/memcg-related/test-mycg-tmpfs.sh
After this fix the number of memory cgroups in /proc/cgroups can now
show > 64k as we allow to leave memory cgroups hanging while releasing
their ids.
Note: Maybe it's a bad idea to allow container to eat kernel
memory with such a hanging cgroups, but yet I don't have better ideas.
https://jira.vzint.dev/browse/PSBM-147473
https://jira.vzint.dev/browse/PSBM-147036
---
mm/memcontrol.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3d4d2fb2bfc6..de84dd1ee210 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6714,11 +6714,6 @@ static void mem_cgroup_id_put_many(struct mem_cgroup
*memcg, unsigned int n)
}
}
-static inline void mem_cgroup_id_get(struct mem_cgroup *memcg)
-{
- mem_cgroup_id_get_many(memcg, 1);
-}
-
static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
{
mem_cgroup_id_put_many(memcg, 1);
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