From: Wesley Atwell <atwellwea@gmail.com>
To: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
edumazet@google.com, ncardwell@google.com, dsahern@kernel.org,
matttbe@kernel.org, martineau@kernel.org, netdev@vger.kernel.org,
mptcp@lists.linux.dev
Cc: kuniyu@google.com, horms@kernel.org, geliang@kernel.org,
corbet@lwn.net, skhan@linuxfoundation.org, rostedt@goodmis.org,
mhiramat@kernel.org, mathieu.desnoyers@efficios.com,
0x7f454c46@gmail.com, linux-doc@vger.kernel.org,
linux-trace-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, atwellwea@gmail.com
Subject: [PATCH net 6/7] tcp: expose rmem and backlog accounting in rcvbuf_grow tracepoints
Date: Wed, 11 Mar 2026 01:55:59 -0600 [thread overview]
Message-ID: <20260311075600.948413-7-atwellwea@gmail.com> (raw)
In-Reply-To: <20260311075600.948413-1-atwellwea@gmail.com>
The receive-window work now depends on keeping sender-visible rwnd and
hard receive-memory accounting aligned.
Expose the current rmem charge and backlog reservation in the TCP and
MPTCP rcvbuf_grow tracepoints so that later drift between advertised
window and local backing is visible during review and debugging.
Signed-off-by: Wesley Atwell <atwellwea@gmail.com>
---
include/trace/events/mptcp.h | 11 +++++++----
include/trace/events/tcp.h | 12 +++++++-----
2 files changed, 14 insertions(+), 9 deletions(-)
diff --git a/include/trace/events/mptcp.h b/include/trace/events/mptcp.h
index 269d949b2025..167970e8e0a5 100644
--- a/include/trace/events/mptcp.h
+++ b/include/trace/events/mptcp.h
@@ -199,6 +199,8 @@ TRACE_EVENT(mptcp_rcvbuf_grow,
__field(__u32, inq)
__field(__u32, space)
__field(__u32, ooo_space)
+ __field(__u32, rmem_alloc)
+ __field(__u32, backlog_len)
__field(__u32, rcvbuf)
__field(__u32, rcv_wnd)
__field(__u8, scaling_ratio)
@@ -228,6 +230,8 @@ TRACE_EVENT(mptcp_rcvbuf_grow,
MPTCP_SKB_CB(msk->ooo_last_skb)->end_seq -
msk->ack_seq;
+ __entry->rmem_alloc = tcp_rmem_used(sk);
+ __entry->backlog_len = READ_ONCE(msk->backlog_len);
__entry->rcvbuf = sk->sk_rcvbuf;
__entry->rcv_wnd = atomic64_read(&msk->rcv_wnd_sent) -
msk->ack_seq;
@@ -248,12 +252,11 @@ TRACE_EVENT(mptcp_rcvbuf_grow,
__entry->skaddr = sk;
),
- TP_printk("time=%u rtt_us=%u copied=%u inq=%u space=%u ooo=%u scaling_ratio=%u "
- "rcvbuf=%u rcv_wnd=%u family=%d sport=%hu dport=%hu saddr=%pI4 "
- "daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c skaddr=%p",
+ TP_printk("time=%u rtt_us=%u copied=%u inq=%u space=%u ooo=%u scaling_ratio=%u rmem_alloc=%u backlog_len=%u rcvbuf=%u rcv_wnd=%u family=%d sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c skaddr=%p",
__entry->time, __entry->rtt_us, __entry->copied,
__entry->inq, __entry->space, __entry->ooo_space,
- __entry->scaling_ratio, __entry->rcvbuf, __entry->rcv_wnd,
+ __entry->scaling_ratio, __entry->rmem_alloc,
+ __entry->backlog_len, __entry->rcvbuf, __entry->rcv_wnd,
__entry->family, __entry->sport, __entry->dport,
__entry->saddr, __entry->daddr, __entry->saddr_v6,
__entry->daddr_v6, __entry->skaddr)
diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
index f155f95cdb6e..92d0bd6be0ba 100644
--- a/include/trace/events/tcp.h
+++ b/include/trace/events/tcp.h
@@ -217,6 +217,8 @@ TRACE_EVENT(tcp_rcvbuf_grow,
__field(__u32, inq)
__field(__u32, space)
__field(__u32, ooo_space)
+ __field(__u32, rmem_alloc)
+ __field(__u32, backlog_len)
__field(__u32, rcvbuf)
__field(__u32, rcv_ssthresh)
__field(__u32, window_clamp)
@@ -247,6 +249,8 @@ TRACE_EVENT(tcp_rcvbuf_grow,
TCP_SKB_CB(tp->ooo_last_skb)->end_seq -
tp->rcv_nxt;
+ __entry->rmem_alloc = tcp_rmem_used(sk);
+ __entry->backlog_len = READ_ONCE(sk->sk_backlog.len);
__entry->rcvbuf = sk->sk_rcvbuf;
__entry->rcv_ssthresh = tp->rcv_ssthresh;
__entry->window_clamp = tp->window_clamp;
@@ -269,13 +273,11 @@ TRACE_EVENT(tcp_rcvbuf_grow,
__entry->sock_cookie = sock_gen_cookie(sk);
),
- TP_printk("time=%u rtt_us=%u copied=%u inq=%u space=%u ooo=%u scaling_ratio=%u rcvbuf=%u "
- "rcv_ssthresh=%u window_clamp=%u rcv_wnd=%u "
- "family=%s sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 "
- "saddrv6=%pI6c daddrv6=%pI6c skaddr=%p sock_cookie=%llx",
+ TP_printk("time=%u rtt_us=%u copied=%u inq=%u space=%u ooo=%u scaling_ratio=%u rmem_alloc=%u backlog_len=%u rcvbuf=%u rcv_ssthresh=%u window_clamp=%u rcv_wnd=%u family=%s sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c skaddr=%p sock_cookie=%llx",
__entry->time, __entry->rtt_us, __entry->copied,
__entry->inq, __entry->space, __entry->ooo_space,
- __entry->scaling_ratio, __entry->rcvbuf,
+ __entry->scaling_ratio, __entry->rmem_alloc,
+ __entry->backlog_len, __entry->rcvbuf,
__entry->rcv_ssthresh, __entry->window_clamp,
__entry->rcv_wnd,
show_family_name(__entry->family),
--
2.34.1
next prev parent reply other threads:[~2026-03-11 7:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-11 7:55 [PATCH net 0/7] tcp: preserve advertised rwnd accounting across receive-memory decisions Wesley Atwell
2026-03-11 7:55 ` [PATCH net 1/7] tcp: track advertise-time scaling basis for rcv_wnd Wesley Atwell
2026-03-11 7:55 ` [PATCH net 2/7] tcp: preserve rcv_wnd snapshot when updating advertised windows Wesley Atwell
2026-03-11 7:55 ` [PATCH net 3/7] tcp: honor advertised receive window in memory admission and clamping Wesley Atwell
2026-03-11 7:55 ` [PATCH net 4/7] tcp: extend TCP_REPAIR_WINDOW with receive-window scaling snapshot Wesley Atwell
2026-03-11 7:55 ` [PATCH net 5/7] mptcp: refresh tcp rcv_wnd snapshot when syncing receive windows Wesley Atwell
2026-03-11 7:55 ` Wesley Atwell [this message]
2026-03-11 7:56 ` [PATCH net 7/7] selftests: tcp_ao: cover legacy and extended TCP_REPAIR_WINDOW layouts Wesley Atwell
2026-03-11 8:34 ` [PATCH net 0/7] tcp: preserve advertised rwnd accounting across receive-memory decisions Eric Dumazet
2026-03-12 0:41 ` Jakub Kicinski
2026-03-12 1:49 ` Eric Dumazet
2026-03-12 0:43 ` Jakub Kicinski
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