From 1b1e13440c1c17efac1000788730468cde16bdd3 Mon Sep 17 00:00:00 2001 From: Roman Gushchin <roman.gushchin@linux.dev> Date: Mon, 24 Jun 2024 17:58:53 -0700 Subject: [PATCH] mm: memcg: introduce memcontrol-v1.c Patch series "mm: memcg: separate legacy cgroup v1 code and put under config option", v2. Cgroups v2 have been around for a while and many users have fully adopted them, so they never use cgroups v1 features and functionality. Yet they have to "pay" for the cgroup v1 support anyway: 1) the kernel binary contains an unused cgroup v1 code, 2) some code paths have additional checks which are not needed, 3) some common structures like task_struct and mem_cgroup contain unused cgroup v1-specific members. Cgroup v1's memory controller has a number of features that are not supported by cgroup v2 and their implementation is pretty much self contained. Most notably, these features are: soft limit reclaim, oom handling in userspace, complicated event notification system, charge migration. Cgroup v1-specific code in memcontrol.c is close to 4k lines in size and it's intervened with generic and cgroup v2-specific code. It's a burden on developers and maintainers. This patchset aims to solve these problems by: 1) moving cgroup v1-specific memcg code to the new mm/memcontrol-v1.c file, 2) putting definitions shared by memcontrol.c and memcontrol-v1.c into the mm/memcontrol-v1.h header, 3) introducing the CONFIG_MEMCG_V1 config option, turned off by default, 4) making memcontrol-v1.c to compile only if CONFIG_MEMCG_V1 is set. If CONFIG_MEMCG_V1 is not set, cgroup v1 memory controller is still available for mounting, however no memory-specific control knobs are present. This patch (of 14): This patch introduces the mm/memcontrol-v1.c source file which will be used for all legacy (cgroup v1) memory cgroup code. It also introduces mm/memcontrol-v1.h to keep declarations shared between mm/memcontrol.c and mm/memcontrol-v1.c. As of now, let's compile it if CONFIG_MEMCG is set, similar to mm/memcontrol.c. Later on it can be switched to use a separate config option, so that the legacy code won't be compiled if not required. Link: https://lkml.kernel.org/r/20240625005906.106920-1-roman.gushchin@linux.dev Link: https://lkml.kernel.org/r/20240625005906.106920-2-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- mm/Makefile | 3 ++- mm/memcontrol-v1.c | 3 +++ mm/memcontrol-v1.h | 7 +++++++ 3 files changed, 12 insertions(+), 1 deletion(-) create mode 100644 mm/memcontrol-v1.c create mode 100644 mm/memcontrol-v1.h diff --git a/mm/Makefile b/mm/Makefile index 8fb85acda1b1c..124d4dea20351 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -26,6 +26,7 @@ KCOV_INSTRUMENT_page_alloc.o := n KCOV_INSTRUMENT_debug-pagealloc.o := n KCOV_INSTRUMENT_kmemleak.o := n KCOV_INSTRUMENT_memcontrol.o := n +KCOV_INSTRUMENT_memcontrol-v1.o := n KCOV_INSTRUMENT_mmzone.o := n KCOV_INSTRUMENT_vmstat.o := n KCOV_INSTRUMENT_failslab.o := n @@ -95,7 +96,7 @@ obj-$(CONFIG_NUMA) += memory-tiers.o obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o obj-$(CONFIG_PAGE_COUNTER) += page_counter.o -obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o +obj-$(CONFIG_MEMCG) += memcontrol.o memcontrol-v1.o vmpressure.o ifdef CONFIG_SWAP obj-$(CONFIG_MEMCG) += swap_cgroup.o endif diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c new file mode 100644 index 0000000000000..a941446ba575b --- /dev/null +++ b/mm/memcontrol-v1.c @@ -0,0 +1,3 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include "memcontrol-v1.h" diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h new file mode 100644 index 0000000000000..7c5f094755ff8 --- /dev/null +++ b/mm/memcontrol-v1.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#ifndef __MM_MEMCONTROL_V1_H +#define __MM_MEMCONTROL_V1_H + + +#endif /* __MM_MEMCONTROL_V1_H */ -- GitLab