The patch titled
Subject: memcg: initiate deprecation of oom_control
has been added to the -mm mm-unstable branch. Its filename is
memcg-initiate-deprecation-of-oom_control.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/memcg-initiate-deprecation-of-oom_control.patch
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: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Subject: memcg: initiate deprecation of oom_control
Date: Wed, 14 Aug 2024 15:00:20 -0700
The oom_control provides functionality to disable memcg oom-killer,
notifications on oom-kill and reading the stats regarding oom-kills. This
interface was mainly introduced to provide functionality for userspace
oom-killers. However it is not robust enough and only supports OOM
handling in the page fault path.
For v2, the users can use the combination of memory.events notifications,
memory.high and PSI to provide userspace OOM-killing functionality.
Actually LMKD in Android and OOMd in systemd and Meta infrastructure
already use PSI in combination with other stats to implement userspace
OOM-killing.
Let's start the deprecation process for v1 and gather the info on how the
current users are using this interface and work on providing a more robust
functionality in v2.
Link: https://lkml.kernel.org/r/20240814220021.3208384-4-shakeel.butt@xxxxxxxxx
Signed-off-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Reviewed-by: T.J. Mercier <tjmercier@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/cgroup-v1/memory.rst | 8 ++++++--
mm/memcontrol-v1.c | 7 +++++++
2 files changed, 13 insertions(+), 2 deletions(-)
--- a/Documentation/admin-guide/cgroup-v1/memory.rst~memcg-initiate-deprecation-of-oom_control
+++ a/Documentation/admin-guide/cgroup-v1/memory.rst
@@ -92,6 +92,8 @@ Brief summary of control files.
This knob is deprecated and shouldn't be
used.
memory.oom_control set/show oom controls.
+ This knob is deprecated and shouldn't be
+ used.
memory.numa_stat show the number of memory usage per numa
node
memory.kmem.limit_in_bytes Deprecated knob to set and read the kernel
@@ -846,8 +848,10 @@ It's applicable for root and non-root cg
.. _cgroup-v1-memory-oom-control:
-10. OOM Control
-===============
+10. OOM Control (DEPRECATED)
+============================
+
+THIS IS DEPRECATED!
memory.oom_control file is for OOM notification and other controls.
--- a/mm/memcontrol-v1.c~memcg-initiate-deprecation-of-oom_control
+++ a/mm/memcontrol-v1.c
@@ -1991,6 +1991,9 @@ static ssize_t memcg_write_event_control
event->register_event = mem_cgroup_usage_register_event;
event->unregister_event = mem_cgroup_usage_unregister_event;
} else if (!strcmp(name, "memory.oom_control")) {
+ pr_warn_once("oom_control is deprecated and will be removed. "
+ "Please report your usecase to linux-mm-@xxxxxxxxx"
+ " if you depend on this functionality. \n");
event->register_event = mem_cgroup_oom_register_event;
event->unregister_event = mem_cgroup_oom_unregister_event;
} else if (!strcmp(name, "memory.pressure_level")) {
@@ -2838,6 +2841,10 @@ static int mem_cgroup_oom_control_write(
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ pr_warn_once("oom_control is deprecated and will be removed. "
+ "Please report your usecase to linux-mm-@xxxxxxxxx if you "
+ "depend on this functionality. \n");
+
/* cannot set to root cgroup and only 0 and 1 are allowed */
if (mem_cgroup_is_root(memcg) || !((val == 0) || (val == 1)))
return -EINVAL;
_
Patches currently in -mm which might be from shakeel.butt@xxxxxxxxx are
memcg-increase-the-valid-index-range-for-memcg-stats.patch
memcg-replace-memcg-id-idr-with-xarray.patch
memcg-replace-memcg-id-idr-with-xarray-v2.patch
memcg-use-ratelimited-stats-flush-in-the-reclaim.patch
memcg-move-v1-only-percpu-stats-in-separate-struct.patch
memcg-move-mem_cgroup_event_ratelimit-to-v1-code.patch
memcg-move-mem_cgroup_charge_statistics-to-v1-code.patch
memcg-move-v1-events-and-statistics-code-to-v1-file.patch
memcg-make-v1-only-functions-static.patch
memcg-allocate-v1-event-percpu-only-on-v1-deployment.patch
memcg-make-pgpgin-and-pgpgout-v1-only.patch
memcg-initiate-deprecation-of-v1-tcp-accounting.patch
memcg-initiate-deprecation-of-v1-soft-limit.patch
memcg-initiate-deprecation-of-oom_control.patch
memcg-initiate-deprecation-of-pressure_level.patch
