* [PATCH v3 mptcp-next 1/3] mptcp: consolidate sockopt synchronization
2023-09-15 14:19 [PATCH v3 mptcp-next 0/3] mptcp: misc improvement Paolo Abeni
@ 2023-09-15 14:19 ` Paolo Abeni
2023-09-15 14:19 ` [PATCH v3 mptcp-next 2/3] mptcp: ignore notsent_lowat setting at the subflow level Paolo Abeni
2023-09-15 14:19 ` [PATCH v3 mptcp-next 3/3] mptcp: refactor sndbuf auto-tuning Paolo Abeni
2 siblings, 0 replies; 5+ messages in thread
From: Paolo Abeni @ 2023-09-15 14:19 UTC (permalink / raw)
To: mptcp
Move the socket option synchronization for active subflows
at subflow creation time. This allows removing the now unused
unlocked variant of such helper.
While at that, clean-up a bit the mptcp_subflow_create_socket()
errors path.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
net/mptcp/protocol.c | 2 --
net/mptcp/sockopt.c | 22 ----------------------
net/mptcp/subflow.c | 18 +++++++++---------
3 files changed, 9 insertions(+), 33 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 3facdc006adc..3a905c122306 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -121,8 +121,6 @@ struct sock *__mptcp_nmpc_sk(struct mptcp_sock *msk)
ret = __mptcp_socket_create(msk);
if (ret)
return ERR_PTR(ret);
-
- mptcp_sockopt_sync(msk, msk->first);
}
return msk->first;
diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c
index 8260202c0066..f44b364b0055 100644
--- a/net/mptcp/sockopt.c
+++ b/net/mptcp/sockopt.c
@@ -1444,28 +1444,6 @@ static void sync_socket_options(struct mptcp_sock *msk, struct sock *ssk)
inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk));
}
-static void __mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
-{
- bool slow = lock_sock_fast(ssk);
-
- sync_socket_options(msk, ssk);
-
- unlock_sock_fast(ssk, slow);
-}
-
-void mptcp_sockopt_sync(struct mptcp_sock *msk, struct sock *ssk)
-{
- struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
-
- msk_owned_by_me(msk);
-
- if (READ_ONCE(subflow->setsockopt_seq) != msk->setsockopt_seq) {
- __mptcp_sockopt_sync(msk, ssk);
-
- subflow->setsockopt_seq = msk->setsockopt_seq;
- }
-}
-
void mptcp_sockopt_sync_locked(struct mptcp_sock *msk, struct sock *ssk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 918c1a235790..1c7ff7247bc0 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -1525,8 +1525,6 @@ int __mptcp_subflow_connect(struct sock *sk, const struct mptcp_addr_info *loc,
if (addr.ss_family == AF_INET6)
addrlen = sizeof(struct sockaddr_in6);
#endif
- mptcp_sockopt_sync(msk, ssk);
-
ssk->sk_bound_dev_if = ifindex;
err = kernel_bind(sf, (struct sockaddr *)&addr, addrlen);
if (err)
@@ -1637,7 +1635,7 @@ int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
err = security_mptcp_add_subflow(sk, sf->sk);
if (err)
- goto release_ssk;
+ goto err_free;
/* the newly created socket has to be in the same cgroup as its parent */
mptcp_attach_cgroup(sk, sf->sk);
@@ -1651,15 +1649,12 @@ int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
get_net_track(net, &sf->sk->ns_tracker, GFP_KERNEL);
sock_inuse_add(net, 1);
err = tcp_set_ulp(sf->sk, "mptcp");
+ if (err)
+ goto err_free;
-release_ssk:
+ mptcp_sockopt_sync_locked(mptcp_sk(sk), sf->sk);
release_sock(sf->sk);
- if (err) {
- sock_release(sf);
- return err;
- }
-
/* the newly created socket really belongs to the owning MPTCP master
* socket, even if for additional subflows the allocation is performed
* by a kernel workqueue. Adjust inode references, so that the
@@ -1679,6 +1674,11 @@ int mptcp_subflow_create_socket(struct sock *sk, unsigned short family,
mptcp_subflow_ops_override(sf->sk);
return 0;
+
+err_free:
+ release_sock(sf->sk);
+ sock_release(sf);
+ return err;
}
static struct mptcp_subflow_context *subflow_create_ctx(struct sock *sk,
--
2.41.0
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v3 mptcp-next 3/3] mptcp: refactor sndbuf auto-tuning.
2023-09-15 14:19 [PATCH v3 mptcp-next 0/3] mptcp: misc improvement Paolo Abeni
2023-09-15 14:19 ` [PATCH v3 mptcp-next 1/3] mptcp: consolidate sockopt synchronization Paolo Abeni
2023-09-15 14:19 ` [PATCH v3 mptcp-next 2/3] mptcp: ignore notsent_lowat setting at the subflow level Paolo Abeni
@ 2023-09-15 14:19 ` Paolo Abeni
2023-09-15 16:25 ` mptcp: refactor sndbuf auto-tuning.: Tests Results MPTCP CI
2 siblings, 1 reply; 5+ messages in thread
From: Paolo Abeni @ 2023-09-15 14:19 UTC (permalink / raw)
To: mptcp
The MPTCP protocol account for the data enqueued on all the subflows
to the main socket send buffer, while the send buffer auto-tuning
algorithm set the main socket send buffer size as the max size among
the subflows.
That causes bad performances when at least one subflow is sndbuf
limited, e.g. due to very high latency, as the MPTCP scheduler can't
even fill such buffer.
Change the send-buffer auto-tuning algorithm to compute the main socket
send buffer size as the sum of all the subflows buffer size.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
v2 -> v3:
- avoid ingremental updates, always recompute sum(ssk->sndbuf) to avoid
drift on memory pressure/decrease
---
net/mptcp/protocol.c | 19 ++++++++++++++--
net/mptcp/protocol.h | 54 ++++++++++++++++++++++++++++++++++++++++----
net/mptcp/subflow.c | 3 +--
3 files changed, 67 insertions(+), 9 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 3a905c122306..7198ded76ae9 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -891,6 +891,7 @@ static bool __mptcp_finish_join(struct mptcp_sock *msk, struct sock *ssk)
mptcp_sockopt_sync_locked(msk, ssk);
mptcp_subflow_joined(msk, ssk);
mptcp_stop_tout_timer(sk);
+ __mptcp_propagate_sndbuf(sk, ssk);
return true;
}
@@ -1077,15 +1078,16 @@ static void mptcp_enter_memory_pressure(struct sock *sk)
struct mptcp_sock *msk = mptcp_sk(sk);
bool first = true;
- sk_stream_moderate_sndbuf(sk);
mptcp_for_each_subflow(msk, subflow) {
struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
if (first)
tcp_enter_memory_pressure(ssk);
sk_stream_moderate_sndbuf(ssk);
+
first = false;
}
+ __mptcp_sync_sndbuf(sk);
}
/* ensure we get enough memory for the frag hdr, beyond some minimal amount of
@@ -2436,6 +2438,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
WRITE_ONCE(msk->first, NULL);
out:
+ __mptcp_sync_sndbuf(sk);
if (need_push)
__mptcp_push_pending(sk, 0);
@@ -3214,7 +3217,7 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk,
* uses the correct data
*/
mptcp_copy_inaddrs(nsk, ssk);
- mptcp_propagate_sndbuf(nsk, ssk);
+ __mptcp_propagate_sndbuf(nsk, ssk);
mptcp_rcv_space_init(msk, ssk);
bh_unlock_sock(nsk);
@@ -3392,6 +3395,8 @@ static void mptcp_release_cb(struct sock *sk)
__mptcp_set_connected(sk);
if (__test_and_clear_bit(MPTCP_ERROR_REPORT, &msk->cb_flags))
__mptcp_error_report(sk);
+ if (__test_and_clear_bit(MPTCP_SYNC_SNDBUF, &msk->cb_flags))
+ __mptcp_sync_sndbuf(sk);
}
__mptcp_update_rmem(sk);
@@ -3437,6 +3442,15 @@ void mptcp_subflow_process_delegated(struct sock *ssk)
mptcp_data_unlock(sk);
mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_SEND);
}
+ if (test_bit(MPTCP_DELEGATE_SNDBUF, &subflow->delegated_status)) {
+ mptcp_data_lock(sk);
+ if (!sock_owned_by_user(sk))
+ __mptcp_sync_sndbuf(sk);
+ else
+ __set_bit(MPTCP_SYNC_SNDBUF, &mptcp_sk(sk)->cb_flags);
+ mptcp_data_unlock(sk);
+ mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_SNDBUF);
+ }
if (test_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status)) {
schedule_3rdack_retransmission(ssk);
mptcp_subflow_delegated_done(subflow, MPTCP_DELEGATE_ACK);
@@ -3523,6 +3537,7 @@ bool mptcp_finish_join(struct sock *ssk)
/* active subflow, already present inside the conn_list */
if (!list_empty(&subflow->node)) {
mptcp_subflow_joined(msk, ssk);
+ mptcp_propagate_sndbuf(parent, ssk);
return true;
}
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index aebc0cc24dad..693330daae26 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -123,6 +123,7 @@
#define MPTCP_RETRANSMIT 4
#define MPTCP_FLUSH_JOIN_LIST 5
#define MPTCP_CONNECTED 6
+#define MPTCP_SYNC_SNDBUF 7
struct mptcp_skb_cb {
u64 map_seq;
@@ -446,6 +447,7 @@ DECLARE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
#define MPTCP_DELEGATE_SEND 0
#define MPTCP_DELEGATE_ACK 1
+#define MPTCP_DELEGATE_SNDBUF 2
/* MPTCP subflow context */
struct mptcp_subflow_context {
@@ -518,6 +520,9 @@ struct mptcp_subflow_context {
u32 setsockopt_seq;
u32 stale_rcv_tstamp;
+ int cached_sndbuf; /* sndbuf size when last synced with the msk sndbuf,
+ * protected by the msk socket lock
+ */
struct sock *tcp_sock; /* tcp sk backpointer */
struct sock *conn; /* parent mptcp_sock */
@@ -780,13 +785,52 @@ static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
}
-static inline bool mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
+static inline void __mptcp_sync_sndbuf(struct sock *sk)
{
- if ((sk->sk_userlocks & SOCK_SNDBUF_LOCK) || ssk->sk_sndbuf <= READ_ONCE(sk->sk_sndbuf))
- return false;
+ struct mptcp_subflow_context *subflow;
+ int ssk_sndbuf, new_sndbuf;
+
+ if (sk->sk_userlocks & SOCK_SNDBUF_LOCK)
+ return;
+
+ new_sndbuf = sock_net(sk)->ipv4.sysctl_tcp_wmem[0];
+ mptcp_for_each_subflow(mptcp_sk(sk), subflow) {
+ ssk_sndbuf = READ_ONCE(mptcp_subflow_tcp_sock(subflow)->sk_sndbuf);
+
+ subflow->cached_sndbuf = ssk_sndbuf;
+ new_sndbuf += ssk_sndbuf;
+ }
+
+ /* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
+ WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
+}
+
+/* The called held both the msk socket and the subflow socket locks,
+ * possibly under BH
+ */
+static inline void __mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+
+ if (READ_ONCE(ssk->sk_sndbuf) - subflow->cached_sndbuf)
+ __mptcp_sync_sndbuf(sk);
+}
+
+/* the caller held only the subflow socket lock, either in process or
+ * BH context. Additionally this can be called under the msk data lock,
+ * so we can't acquire such lock here: let the delegate action acquires
+ * the needed locks in suitable order.
+ */
+static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk);
+
+ if (likely(READ_ONCE(ssk->sk_sndbuf) == subflow->cached_sndbuf))
+ return;
- WRITE_ONCE(sk->sk_sndbuf, ssk->sk_sndbuf);
- return true;
+ local_bh_disable();
+ mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_SNDBUF);
+ local_bh_enable();
}
static inline void mptcp_write_space(struct sock *sk)
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 1c7ff7247bc0..5a901f14e1d7 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -421,6 +421,7 @@ static bool subflow_use_different_dport(struct mptcp_sock *msk, const struct soc
void __mptcp_set_connected(struct sock *sk)
{
+ __mptcp_propagate_sndbuf(sk, mptcp_sk(sk)->first);
if (sk->sk_state == TCP_SYN_SENT) {
inet_sk_state_store(sk, TCP_ESTABLISHED);
sk->sk_state_change(sk);
@@ -472,7 +473,6 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
return;
msk = mptcp_sk(parent);
- mptcp_propagate_sndbuf(parent, sk);
subflow->rel_write_seq = 1;
subflow->conn_finished = 1;
subflow->ssn_offset = TCP_SKB_CB(skb)->seq;
@@ -1728,7 +1728,6 @@ static void subflow_state_change(struct sock *sk)
msk = mptcp_sk(parent);
if (subflow_simultaneous_connect(sk)) {
- mptcp_propagate_sndbuf(parent, sk);
mptcp_do_fallback(sk);
mptcp_rcv_space_init(msk, sk);
pr_fallback(msk);
--
2.41.0
^ permalink raw reply related [flat|nested] 5+ messages in thread