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| author | Kuniyuki Iwashima <kuniyu@google.com> | 2025-08-15 23:16:09 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-08-20 05:20:58 +0300 |
| commit | 68889dfd547bd8eabc5a98b58475d7b901cf5129 (patch) | |
| tree | 00d65142f5cb1ee7b199e4f820c38126fcde04ab /include/linux/memcontrol.h | |
| parent | 5c69e0b395c1ffb37fd6fbdbd428353fc0894005 (diff) | |
| download | linux-68889dfd547bd8eabc5a98b58475d7b901cf5129.tar.xz | |
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 <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Link: https://patch.msgid.link/20250815201712.1745332-2-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/linux/memcontrol.h')
| -rw-r--r-- | include/linux/memcontrol.h | 6 |
1 files changed, 6 insertions, 0 deletions
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; |