[PATCH 6/7] memcg: allocate v1 event percpu only on v1 deployment

From: Shakeel Butt
Date: Thu Aug 15 2024 - 01:06:51 EST


Currently memcg->events_percpu gets allocated on v2 deployments. Let's
move the allocation to v1 only codebase. This is not needed in v2.

Signed-off-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
---
include/linux/memcontrol.h | 3 ++-
mm/memcontrol-v1.c | 19 +++++++++++++++++++
mm/memcontrol-v1.h | 26 +++++++-------------------
3 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e21a1541adeb..1f86d01d3b97 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -255,7 +255,6 @@ struct mem_cgroup {
struct list_head objcg_list;

struct memcg_vmstats_percpu __percpu *vmstats_percpu;
- struct memcg1_events_percpu __percpu *events_percpu;

#ifdef CONFIG_CGROUP_WRITEBACK
struct list_head cgwb_list;
@@ -277,6 +276,8 @@ struct mem_cgroup {
struct page_counter kmem; /* v1 only */
struct page_counter tcpmem; /* v1 only */

+ struct memcg1_events_percpu __percpu *events_percpu;
+
unsigned long soft_limit;

/* protected by memcg_oom_lock */
diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
index 0589d08c1599..81d8819f13cd 100644
--- a/mm/memcontrol-v1.c
+++ b/mm/memcontrol-v1.c
@@ -1442,6 +1442,12 @@ static void mem_cgroup_threshold(struct mem_cgroup *memcg)
}
}

+/* Cgroup1: threshold notifications & softlimit tree updates */
+struct memcg1_events_percpu {
+ unsigned long nr_page_events;
+ unsigned long targets[MEM_CGROUP_NTARGETS];
+};
+
static void memcg1_charge_statistics(struct mem_cgroup *memcg, int nr_pages)
{
/* pagein of a big page is an event. So, ignore page size */
@@ -3049,6 +3055,19 @@ bool memcg1_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
return false;
}

+bool memcg1_alloc_events(struct mem_cgroup *memcg)
+{
+ memcg->events_percpu = alloc_percpu_gfp(struct memcg1_events_percpu,
+ GFP_KERNEL_ACCOUNT);
+ return !!memcg->events_percpu;
+}
+
+void memcg1_free_events(struct mem_cgroup *memcg)
+{
+ if (memcg->events_percpu)
+ free_percpu(memcg->events_percpu);
+}
+
static int __init memcg1_init(void)
{
int node;
diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h
index 0a9f3f9c2362..3bb8b3030e61 100644
--- a/mm/memcontrol-v1.h
+++ b/mm/memcontrol-v1.h
@@ -55,12 +55,6 @@ enum mem_cgroup_events_target {
MEM_CGROUP_NTARGETS,
};

-/* Cgroup1: threshold notifications & softlimit tree updates */
-struct memcg1_events_percpu {
- unsigned long nr_page_events;
- unsigned long targets[MEM_CGROUP_NTARGETS];
-};
-
unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap);

void drain_all_stock(struct mem_cgroup *root_memcg);
@@ -72,21 +66,12 @@ unsigned long memcg_page_state_output(struct mem_cgroup *memcg, int item);
unsigned long memcg_page_state_local_output(struct mem_cgroup *memcg, int item);
int memory_stat_show(struct seq_file *m, void *v);

-static inline bool memcg1_alloc_events(struct mem_cgroup *memcg)
-{
- memcg->events_percpu = alloc_percpu_gfp(struct memcg1_events_percpu,
- GFP_KERNEL_ACCOUNT);
- return !!memcg->events_percpu;
-}
-
-static inline void memcg1_free_events(struct mem_cgroup *memcg)
-{
- if (memcg->events_percpu)
- free_percpu(memcg->events_percpu);
-}
-
/* Cgroup v1-specific declarations */
#ifdef CONFIG_MEMCG_V1
+
+bool memcg1_alloc_events(struct mem_cgroup *memcg);
+void memcg1_free_events(struct mem_cgroup *memcg);
+
void memcg1_memcg_init(struct mem_cgroup *memcg);
void memcg1_remove_from_trees(struct mem_cgroup *memcg);

@@ -139,6 +124,9 @@ extern struct cftype mem_cgroup_legacy_files[];

#else /* CONFIG_MEMCG_V1 */

+static inline bool memcg1_alloc_events(struct mem_cgroup *memcg) { return true; }
+static inline void memcg1_free_events(struct mem_cgroup *memcg) {}
+
static inline void memcg1_memcg_init(struct mem_cgroup *memcg) {}
static inline void memcg1_remove_from_trees(struct mem_cgroup *memcg) {}
static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg) {}
--
2.43.5