If memcg is enabled, accept() acquires lock_sock() twice for each new
TCP/MPTCP socket in inet_csk_accept() and __inet_accept().
Let's move memcg operations from inet_csk_accept() to __inet_accept().
This makes easier to add a BPF hook that covers sk_prot.memory_allocated
users (TCP, MPTCP, SCTP) in a single place.
Two notes:
1)
SCTP somehow allocates a new socket by sk_alloc() in sk->sk_prot->accept()
and clones fields manually, instead of using sk_clone_lock().
For SCTP, mem_cgroup_sk_alloc() has been called before __inet_accept(),
so I added the protocol tests in __inet_accept(), but this can be removed
once SCTP uses sk_clone_lock().
2)
The single if block is separated into two because we will add a new bpf
hook between the blocks, where a bpf prog can add a flag in sk->sk_memcg.
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
---
net/ipv4/af_inet.c | 22 ++++++++++++++++++++++
net/ipv4/inet_connection_sock.c | 25 -------------------------
2 files changed, 22 insertions(+), 25 deletions(-)
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 76e38092cd8a..ae83ecda3983 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -753,6 +753,28 @@ EXPORT_SYMBOL(inet_stream_connect);
void __inet_accept(struct socket *sock, struct socket *newsock, struct sock *newsk)
{
+ gfp_t gfp = GFP_KERNEL | __GFP_NOFAIL;
+
+ /* TODO: use sk_clone_lock() in SCTP and remove protocol checks */
+ if (mem_cgroup_sockets_enabled &&
+ (!IS_ENABLED(CONFIG_IP_SCTP) ||
+ sk_is_tcp(newsk) || sk_is_mptcp(newsk))) {
+ mem_cgroup_sk_alloc(newsk);
+ kmem_cache_charge(newsk, gfp);
+ }
+
+ if (mem_cgroup_sk_enabled(newsk)) {
+ int amt;
+
+ /* The socket has not been accepted yet, no need
+ * to look at newsk->sk_wmem_queued.
+ */
+ amt = sk_mem_pages(newsk->sk_forward_alloc +
+ atomic_read(&newsk->sk_rmem_alloc));
+ if (amt)
+ mem_cgroup_sk_charge(newsk, amt, gfp);
+ }
+
sock_rps_record_flow(newsk);
WARN_ON(!((1 << newsk->sk_state) &
(TCPF_ESTABLISHED | TCPF_SYN_RECV |
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 0ef1eacd539d..ed10b959a906 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -708,31 +708,6 @@ struct sock *inet_csk_accept(struct sock *sk, struct proto_accept_arg *arg)
release_sock(sk);
- if (mem_cgroup_sockets_enabled) {
- gfp_t gfp = GFP_KERNEL | __GFP_NOFAIL;
- int amt = 0;
-
- /* atomically get the memory usage, set and charge the
- * newsk->sk_memcg.
- */
- lock_sock(newsk);
-
- mem_cgroup_sk_alloc(newsk);
- if (mem_cgroup_from_sk(newsk)) {
- /* The socket has not been accepted yet, no need
- * to look at newsk->sk_wmem_queued.
- */
- amt = sk_mem_pages(newsk->sk_forward_alloc +
- atomic_read(&newsk->sk_rmem_alloc));
- }
-
- if (amt)
- mem_cgroup_sk_charge(newsk, amt, gfp);
- kmem_cache_charge(newsk, gfp);
-
- release_sock(newsk);
- }
-
if (req)
reqsk_put(req);
--
2.51.0.261.g7ce5a0a67e-goog
