Guard cgroup v1-related members of task_struct under the CONFIG_MEMCG_V1
config option, so that users who adopted cgroup v2 don't have to waste
the memory for fields which are never accessed.
Signed-off-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
---
include/linux/memcontrol.h | 2 +-
init/Kconfig | 9 +++++++++
mm/Makefile | 3 ++-
mm/memcontrol-v1.h | 21 ++++++++++++++++++++-
mm/memcontrol.c | 10 +++++++---
5 files changed, 39 insertions(+), 6 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 7474b20a5d3f5..aaa97ec0634f7 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1845,7 +1845,7 @@ static inline bool mem_cgroup_zswap_writeback_enabled(struct mem_cgroup *memcg)
/* Cgroup v1-related declarations */
-#ifdef CONFIG_MEMCG
+#ifdef CONFIG_MEMCG_V1
unsigned long memcg1_soft_limit_reclaim(pg_data_t *pgdat, int order,
gfp_t gfp_mask,
unsigned long *total_scanned);
diff --git a/init/Kconfig b/init/Kconfig
index febdea2afc3be..5191b6435b4e7 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -969,6 +969,15 @@ config MEMCG
help
Provides control over the memory footprint of tasks in a cgroup.
+config MEMCG_V1
+ bool "Legacy memory controller"
+ depends on MEMCG
+ default n
+ help
+ Legacy cgroup v1 memory controller.
+
+ San N is unsure.
+
config MEMCG_KMEM
bool
depends on MEMCG
diff --git a/mm/Makefile b/mm/Makefile
index 124d4dea20351..d2915f8c9dc01 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -96,7 +96,8 @@ 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-$(CONFIG_MEMCG) += memcontrol.o memcontrol-v1.o vmpressure.o
+obj-$(CONFIG_MEMCG_V1) += memcontrol-v1.o
+obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
ifdef CONFIG_SWAP
obj-$(CONFIG_MEMCG) += swap_cgroup.o
endif
diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h
index 89d4207930481..64b053d7f131e 100644
--- a/mm/memcontrol-v1.h
+++ b/mm/memcontrol-v1.h
@@ -75,7 +75,7 @@ unsigned long memcg_page_state_local_output(struct mem_cgroup *memcg, int item);
int memory_stat_show(struct seq_file *m, void *v);
/* Cgroup v1-specific declarations */
-
+#ifdef CONFIG_MEMCG_V1
void memcg1_remove_from_trees(struct mem_cgroup *memcg);
static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg)
@@ -110,4 +110,23 @@ void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s);
extern struct cftype memsw_files[];
extern struct cftype mem_cgroup_legacy_files[];
+#else /* CONFIG_MEMCG_V1 */
+
+static inline void memcg1_remove_from_trees(struct mem_cgroup *memcg) {}
+static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg) {}
+static inline bool memcg1_wait_acct_move(struct mem_cgroup *memcg) { return false; }
+static inline void memcg1_css_offline(struct mem_cgroup *memcg) {}
+
+static inline bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked) { return true; }
+static inline void memcg1_oom_finish(struct mem_cgroup *memcg, bool locked) {}
+static inline void memcg1_oom_recover(struct mem_cgroup *memcg) {}
+
+static inline void memcg1_check_events(struct mem_cgroup *memcg, int nid) {}
+
+static inline void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) {}
+
+extern struct cftype memsw_files[];
+extern struct cftype mem_cgroup_legacy_files[];
+#endif /* CONFIG_MEMCG_V1 */
+
#endif /* __MM_MEMCONTROL_V1_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8a28ba4ca93ea..8cbceeb9c7ac4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4473,18 +4473,20 @@ struct cgroup_subsys memory_cgrp_subsys = {
.css_free = mem_cgroup_css_free,
.css_reset = mem_cgroup_css_reset,
.css_rstat_flush = mem_cgroup_css_rstat_flush,
- .can_attach = memcg1_can_attach,
#if defined(CONFIG_LRU_GEN) || defined(CONFIG_MEMCG_KMEM)
.attach = mem_cgroup_attach,
#endif
- .cancel_attach = memcg1_cancel_attach,
- .post_attach = memcg1_move_task,
#ifdef CONFIG_MEMCG_KMEM
.fork = mem_cgroup_fork,
.exit = mem_cgroup_exit,
#endif
.dfl_cftypes = memory_files,
+#ifdef CONFIG_MEMCG_V1
+ .can_attach = memcg1_can_attach,
+ .cancel_attach = memcg1_cancel_attach,
+ .post_attach = memcg1_move_task,
.legacy_cftypes = mem_cgroup_legacy_files,
+#endif
.early_init = 0,
};
@@ -5655,7 +5657,9 @@ static int __init mem_cgroup_swap_init(void)
return 0;
WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files));
+#ifdef CONFIG_MEMCG_V1
WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files));
+#endif
#if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP)
WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, zswap_files));
#endif
--
2.45.1
