This series collects a few follow-up for the backlog refactor, with some
of them posing as fixes just to confuse the enemy (or feel the season
mood)

Targeting net-next as the issues addressed are very old, the change
is quite invasive and, as mentioned, based on the BL refactor.

Only patch 2/7 could be considered for net, but still included because
somewhat related to the others and to keep my life easy.

Overall this:
- introduces a tracepoint similar to tcp useful to track down the issues
  addressed here
- avoid rx drop in corner case scenarios, improving tput stability and
  peak tput over fast link
- refactor the rcv space and rtt estimator, overall making DRS more
  correct and avoiding rcv buffer drifting to tcp_rmem[2], which in
  turn makes the tput more stable and less bursty
---
v2 -> v3:
  - use __entry->family in patch 1/7
  - more verbose commit message for patch 6/7

v1 -> v2:
  - new patch 1/7
  - old patch 2/4 has been split in 3: 3/7, 4/7 and 5/7
  - refactor both the rcv space init and rtt estimator

Paolo Abeni (7):
  trace: mptcp: add mptcp_rcvbuf_grow tracepoint
  mptcp: avoid unneeded subflow-level drops.
  mptcp: fix receive space timestamp initialization.
  mptcp: consolidate rcv space init
  mptcp: better rcv space initialization
  mptcp: better mptcp-level RTT estimator
  mptcp: add receive queue awareness in tcp_rcv_space_adjust()

 include/trace/events/mptcp.h |  77 ++++++++++++++++++
 net/mptcp/options.c          |  31 +++++++
 net/mptcp/protocol.c         | 154 ++++++++++++++++++++++-------------
 net/mptcp/protocol.h         |  44 +++++++++-
 net/mptcp/subflow.c          |   5 +-
 5 files changed, 250 insertions(+), 61 deletions(-)

-- 
2.51.0

Hi Paolo,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal (except selftest_mptcp_join): Success! ✅
- KVM Validation: normal (only selftest_mptcp_join): Success! ✅
- KVM Validation: debug (except selftest_mptcp_join): Success! ✅
- KVM Validation: debug (only selftest_mptcp_join): Success! ✅
- KVM Validation: btf-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/19163223705

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/0a48f35af4c5
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1020786


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)