The patch titled Subject: memcg: drop kmem.limit_in_bytes has been added to the -mm mm-unstable branch. Its filename is memcg-drop-kmemlimit_in_bytes.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: Michal Hocko mhocko@suse.com Subject: memcg: drop kmem.limit_in_bytes Date: Tue, 4 Jul 2023 13:52:40 +0200
kmem.limit_in_bytes (v1 way to limit kernel memory usage) has been deprecated since 58056f77502f ("memcg, kmem: further deprecate kmem.limit_in_bytes") merged in 5.16. We haven't heard about any serious users since then but it seems that the mere presence of the file is causing more harm than good. We (SUSE) have had several bug reports from customers where Docker based containers started to fail because a write to kmem.limit_in_bytes has failed.
This was unexpected because runc code only expects ENOENT (kmem disabled) or EBUSY (tasks already running within cgroup). So a new error code was unexpected and the whole container startup failed. This has been later addressed by https://github.com/opencontainers/runc/commit/52390d68040637dfc77f9fda6bbe70... so current Docker runtimes do not suffer from the problem anymore. There are still older version of Docker in use and likely hard to get rid of completely.
Address this by wiping out the file completely and effectively get back to pre 4.5 era and CONFIG_MEMCG_KMEM=n configuration.
I would recommend backporting to stable trees which have picked up 58056f77502f ("memcg, kmem: further deprecate kmem.limit_in_bytes").
Link: https://lkml.kernel.org/r/20230704115240.14672-1-mhocko@kernel.org Signed-off-by: Michal Hocko mhocko@suse.com Cc: Johannes Weiner hannes@cmpxchg.org Cc: Muchun Song muchun.song@linux.dev Cc: Roman Gushchin roman.gushchin@linux.dev Cc: Shakeel Butt shakeelb@google.com Cc: Tejun Heo tj@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
Documentation/admin-guide/cgroup-v1/memory.rst | 2 -- mm/memcontrol.c | 13 ------------- 2 files changed, 15 deletions(-)
--- a/Documentation/admin-guide/cgroup-v1/memory.rst~memcg-drop-kmemlimit_in_bytes +++ a/Documentation/admin-guide/cgroup-v1/memory.rst @@ -92,8 +92,6 @@ Brief summary of control files. memory.oom_control set/show oom controls. memory.numa_stat show the number of memory usage per numa node - memory.kmem.limit_in_bytes This knob is deprecated and writing to - it will return -ENOTSUPP. memory.kmem.usage_in_bytes show current kernel memory allocation memory.kmem.failcnt show the number of kernel memory usage hits limits --- a/mm/memcontrol.c~memcg-drop-kmemlimit_in_bytes +++ a/mm/memcontrol.c @@ -3708,9 +3708,6 @@ static u64 mem_cgroup_read_u64(struct cg case _MEMSWAP: counter = &memcg->memsw; break; - case _KMEM: - counter = &memcg->kmem; - break; case _TCP: counter = &memcg->tcpmem; break; @@ -3871,10 +3868,6 @@ static ssize_t mem_cgroup_write(struct k case _MEMSWAP: ret = mem_cgroup_resize_max(memcg, nr_pages, true); break; - case _KMEM: - /* kmem.limit_in_bytes is deprecated. */ - ret = -EOPNOTSUPP; - break; case _TCP: ret = memcg_update_tcp_max(memcg, nr_pages); break; @@ -5086,12 +5079,6 @@ static struct cftype mem_cgroup_legacy_f }, #endif { - .name = "kmem.limit_in_bytes", - .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT), - .write = mem_cgroup_write, - .read_u64 = mem_cgroup_read_u64, - }, - { .name = "kmem.usage_in_bytes", .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE), .read_u64 = mem_cgroup_read_u64, _
Patches currently in -mm which might be from mhocko@suse.com are
memcg-drop-kmemlimit_in_bytes.patch