From: Jakub Kicinski Date: Thu, 30 Oct 2025 00:30:45 +0000 (-0700) Subject: Merge branch 'tcp-fix-receive-autotune-again' X-Git-Tag: v6.18-rc4~24^2~14 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bcc843bb0e7468de7f2de8bc2e3fa5a54dd1f3d0;p=thirdparty%2Fkernel%2Fstable.git Merge branch 'tcp-fix-receive-autotune-again' Matthieu Baerts says: ==================== tcp: fix receive autotune again Neal Cardwell found that recent kernels were having RWIN limited issues, even when net.ipv4.tcp_rmem[2] was set to a very big value like 512MB. He suspected that tcp_stream default buffer size (64KB) was triggering heuristic added in ea33537d8292 ("tcp: add receive queue awareness in tcp_rcv_space_adjust()"). After more testing, it turns out the bug was added earlier with commit 65c5287892e9 ("tcp: fix sk_rcvbuf overshoot"). I forgot once again that DRS has one RTT latency. MPTCP also got the same issue. This series : - Prevents calling tcp_rcvbuf_grow() on some MPTCP subflows. - adds rcv_ssthresh, window_clamp and rcv_wnd to trace_tcp_rcvbuf_grow(). - Refactors code in a patch with no functional changes. - Fixes the issue in the final patch. ==================== Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-0-74b43ba4c84c@kernel.org Signed-off-by: Jakub Kicinski --- bcc843bb0e7468de7f2de8bc2e3fa5a54dd1f3d0