From 68889dfd547bd8eabc5a98b58475d7b901cf5129 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 15 Aug 2025 20:16:09 +0000 Subject: mptcp: Fix up subflow's memcg when CONFIG_SOCK_CGROUP_DATA=n. When sk_alloc() allocates a socket, mem_cgroup_sk_alloc() sets sk->sk_memcg based on the current task. MPTCP subflow socket creation is triggered from userspace or an in-kernel worker. In the latter case, sk->sk_memcg is not what we want. So, we fix it up from the parent socket's sk->sk_memcg in mptcp_attach_cgroup(). Although the code is placed under #ifdef CONFIG_MEMCG, it is buried under #ifdef CONFIG_SOCK_CGROUP_DATA. The two configs are orthogonal. If CONFIG_MEMCG is enabled without CONFIG_SOCK_CGROUP_DATA, the subflow's memory usage is not charged correctly. Let's move the code out of the wrong ifdef guard. Note that sk->sk_memcg is freed in sk_prot_free() and the parent sk holds the refcnt of memcg->css here, so we don't need to use css_tryget(). Fixes: 3764b0c5651e3 ("mptcp: attach subflow socket to parent cgroup") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Acked-by: Matthieu Baerts (NGI0) Acked-by: Shakeel Butt Link: https://patch.msgid.link/20250815201712.1745332-2-kuniyu@google.com Signed-off-by: Jakub Kicinski --- include/linux/memcontrol.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 785173aa0739..25921fbec685 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1604,6 +1604,7 @@ extern struct static_key_false memcg_sockets_enabled_key; #define mem_cgroup_sockets_enabled static_branch_unlikely(&memcg_sockets_enabled_key) void mem_cgroup_sk_alloc(struct sock *sk); void mem_cgroup_sk_free(struct sock *sk); +void mem_cgroup_sk_inherit(const struct sock *sk, struct sock *newsk); #if BITS_PER_LONG < 64 static inline void mem_cgroup_set_socket_pressure(struct mem_cgroup *memcg) @@ -1661,6 +1662,11 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg); #define mem_cgroup_sockets_enabled 0 static inline void mem_cgroup_sk_alloc(struct sock *sk) { }; static inline void mem_cgroup_sk_free(struct sock *sk) { }; + +static inline void mem_cgroup_sk_inherit(const struct sock *sk, struct sock *newsk) +{ +} + static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg) { return false; -- cgit v1.2.3 From bb178c6bc08525d758a57775458d644304011bf8 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 15 Aug 2025 20:16:16 +0000 Subject: net-memcg: Pass struct sock to mem_cgroup_sk_(un)?charge(). We will store a flag in the lowest bit of sk->sk_memcg. Then, we cannot pass the raw pointer to mem_cgroup_charge_skmem() and mem_cgroup_uncharge_skmem(). Let's pass struct sock to the functions. While at it, they are renamed to match other functions starting with mem_cgroup_sk_. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Acked-by: Roman Gushchin Acked-by: Shakeel Butt Link: https://patch.msgid.link/20250815201712.1745332-9-kuniyu@google.com Signed-off-by: Jakub Kicinski --- include/linux/memcontrol.h | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 25921fbec685..0837d3de3a68 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1596,15 +1596,16 @@ static inline void mem_cgroup_flush_foreign(struct bdi_writeback *wb) #endif /* CONFIG_CGROUP_WRITEBACK */ struct sock; -bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages, - gfp_t gfp_mask); -void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages); #ifdef CONFIG_MEMCG extern struct static_key_false memcg_sockets_enabled_key; #define mem_cgroup_sockets_enabled static_branch_unlikely(&memcg_sockets_enabled_key) + void mem_cgroup_sk_alloc(struct sock *sk); void mem_cgroup_sk_free(struct sock *sk); void mem_cgroup_sk_inherit(const struct sock *sk, struct sock *newsk); +bool mem_cgroup_sk_charge(const struct sock *sk, unsigned int nr_pages, + gfp_t gfp_mask); +void mem_cgroup_sk_uncharge(const struct sock *sk, unsigned int nr_pages); #if BITS_PER_LONG < 64 static inline void mem_cgroup_set_socket_pressure(struct mem_cgroup *memcg) @@ -1660,13 +1661,31 @@ void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id); void reparent_shrinker_deferred(struct mem_cgroup *memcg); #else #define mem_cgroup_sockets_enabled 0 -static inline void mem_cgroup_sk_alloc(struct sock *sk) { }; -static inline void mem_cgroup_sk_free(struct sock *sk) { }; + +static inline void mem_cgroup_sk_alloc(struct sock *sk) +{ +} + +static inline void mem_cgroup_sk_free(struct sock *sk) +{ +} static inline void mem_cgroup_sk_inherit(const struct sock *sk, struct sock *newsk) { } +static inline bool mem_cgroup_sk_charge(const struct sock *sk, + unsigned int nr_pages, + gfp_t gfp_mask) +{ + return false; +} + +static inline void mem_cgroup_sk_uncharge(const struct sock *sk, + unsigned int nr_pages) +{ +} + static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg) { return false; -- cgit v1.2.3 From b2ffd10cddde47cc6830e4981e91e3215def62b1 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Fri, 15 Aug 2025 20:16:17 +0000 Subject: net-memcg: Pass struct sock to mem_cgroup_sk_under_memory_pressure(). We will store a flag in the lowest bit of sk->sk_memcg. Then, we cannot pass the raw pointer to mem_cgroup_under_socket_pressure(). Let's pass struct sock to it and rename the function to match other functions starting with mem_cgroup_sk_. Note that the helper is moved to sock.h to use mem_cgroup_from_sk(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Acked-by: Roman Gushchin Acked-by: Shakeel Butt Link: https://patch.msgid.link/20250815201712.1745332-10-kuniyu@google.com Signed-off-by: Jakub Kicinski --- include/linux/memcontrol.h | 18 ------------------ 1 file changed, 18 deletions(-) (limited to 'include/linux') diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 0837d3de3a68..fb27e3d2fdac 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1642,19 +1642,6 @@ static inline u64 mem_cgroup_get_socket_pressure(struct mem_cgroup *memcg) } #endif -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_before64(get_jiffies_64(), mem_cgroup_get_socket_pressure(memcg))) - return true; - } while ((memcg = parent_mem_cgroup(memcg))); - return false; -} - int alloc_shrinker_info(struct mem_cgroup *memcg); void free_shrinker_info(struct mem_cgroup *memcg); void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id); @@ -1686,11 +1673,6 @@ static inline void mem_cgroup_sk_uncharge(const struct sock *sk, { } -static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg) -{ - return false; -} - static inline void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id) { -- cgit v1.2.3