[PATCH v1 2/9] mm: memcg: factor out legacy socket memory accounting code

Roman Gushchin
2024-06-28T21:03:56Z

Move out the legacy cgroup v1 socket memory accounting code into
mm/memcontrol-v1.c.

This commit introduces three new functions: memcg1_tcpmem_active(),
memcg1_charge_skmem() and memcg1_uncharge_skmem(), which contain
all cgroup v1-specific code and become trivial if CONFIG_MEMCG_V1
isn't set.

Note, that !!memcg->tcpmem_pressure check in
mem_cgroup_under_socket_pressure() can't be easily moved into
memcontrol-v1.h without including memcontrol-v1.h from memcontrol.h
which isn't a good idea, so it's better to just #ifdef it.

Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
---
include/linux/memcontrol.h | 2 ++
mm/memcontrol-v1.c | 17 +++++++++++++++++
mm/memcontrol-v1.h | 16 ++++++++++++++++
mm/memcontrol.c | 22 +++++-----------------
4 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 796cfa842346..44ab6394c9ed 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1650,8 +1650,10 @@ void mem_cgroup_sk_alloc(struct sock *sk);
void mem_cgroup_sk_free(struct sock *sk);
static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
{
+#ifdef CONFIG_MEMCG_V1
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
return !!memcg->tcpmem_pressure;
+#endif /* CONFIG_MEMCG_V1 */
do {
if (time_before(jiffies, READ_ONCE(memcg->socket_pressure)))
return true;
diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c
index c73a0ff0cc39..c9b4c3e4797d 100644
--- a/mm/memcontrol-v1.c
+++ b/mm/memcontrol-v1.c
@@ -2925,6 +2925,23 @@ void memcg1_account_kmem(struct mem_cgroup *memcg, int nr_pages)
}
#endif /* CONFIG_MEMCG_KMEM */

+bool memcg1_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
+ gfp_t gfp_mask)
+{
+ struct page_counter *fail;
+
+ if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
+ memcg->tcpmem_pressure = 0;
+ return true;
+ }
+ memcg->tcpmem_pressure = 1;
+ if (gfp_mask & __GFP_NOFAIL) {
+ page_counter_charge(&memcg->tcpmem, nr_pages);
+ return true;
+ }
+ return false;
+}
+
static int __init memcg1_init(void)
{
int node;
diff --git a/mm/memcontrol-v1.h b/mm/memcontrol-v1.h
index 61620e2b0bf0..c8e5119223bb 100644
--- a/mm/memcontrol-v1.h
+++ b/mm/memcontrol-v1.h
@@ -108,6 +108,17 @@ void memcg1_check_events(struct mem_cgroup *memcg, int nid);
void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s);

void memcg1_account_kmem(struct mem_cgroup *memcg, int nr_pages);
+static inline bool memcg1_tcpmem_active(struct mem_cgroup *memcg)
+{
+ return memcg->tcpmem_active;
+}
+bool memcg1_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
+ gfp_t gfp_mask);
+static inline void memcg1_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
+{
+ page_counter_uncharge(&memcg->tcpmem, nr_pages);
+}
+
extern struct cftype memsw_files[];
extern struct cftype mem_cgroup_legacy_files[];

@@ -127,6 +138,11 @@ 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) {}

static inline void memcg1_account_kmem(struct mem_cgroup *memcg, int nr_pages) {}
+static inline bool memcg1_tcpmem_active(struct mem_cgroup *memcg) { return false; }
+static inline bool memcg1_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
+ gfp_t gfp_mask) { return true; }
+static inline void memcg1_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages) {}
+
extern struct cftype memsw_files[];
extern struct cftype mem_cgroup_legacy_files[];
#endif /* CONFIG_MEMCG_V1 */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 802a077e2e2f..2c0605bbbb31 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3788,7 +3788,7 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
static_branch_dec(&memcg_sockets_enabled_key);

- if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg1_tcpmem_active(memcg))
static_branch_dec(&memcg_sockets_enabled_key);

#if defined(CONFIG_MEMCG_KMEM)
@@ -5013,7 +5013,7 @@ void mem_cgroup_sk_alloc(struct sock *sk)
memcg = mem_cgroup_from_task(current);
if (mem_cgroup_is_root(memcg))
goto out;
- if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg1_tcpmem_active(memcg))
goto out;
if (css_tryget(&memcg->css))
sk->sk_memcg = memcg;
@@ -5039,20 +5039,8 @@ void mem_cgroup_sk_free(struct sock *sk)
bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
gfp_t gfp_mask)
{
- if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
- struct page_counter *fail;
-
- if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
- memcg->tcpmem_pressure = 0;
- return true;
- }
- memcg->tcpmem_pressure = 1;
- if (gfp_mask & __GFP_NOFAIL) {
- page_counter_charge(&memcg->tcpmem, nr_pages);
- return true;
- }
- return false;
- }
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ return memcg1_charge_skmem(memcg, nr_pages, gfp_mask);

if (try_charge(memcg, gfp_mask, nr_pages) == 0) {
mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
@@ -5070,7 +5058,7 @@ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages,
void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
{
if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
- page_counter_uncharge(&memcg->tcpmem, nr_pages);
+ memcg1_uncharge_skmem(memcg, nr_pages);
return;
}

--
2.45.2.803.g4e1b14247a-goog