From: David S. Miller Date: Sun, 13 Aug 2023 11:21:38 +0000 (+0100) Subject: Merge branch 'tcp-oom-probe' X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=86f03776f6d58558912bc05158fa75add1886aca;p=linux.git Merge branch 'tcp-oom-probe' Menglong Dong says: ==================== net: tcp: support probing OOM In this series, we make some small changes to make the tcp retransmission become zero-window probes if the receiver drops the skb because of memory pressure. In the 1st patch, we reply a zero-window ACK if the skb is dropped because out of memory, instead of dropping the skb silently. In the 2nd patch, we allow a zero-window ACK to update the window. In the 3rd patch, fix unexcepted socket die when snd_wnd is 0 in tcp_retransmit_timer(). In the 4th patch, we refactor the debug message in tcp_retransmit_timer() to make it more correct. After these changes, the tcp can probe the OOM of the receiver forever. Changes since v3: - make the timeout "2 * TCP_RTO_MAX" in the 3rd patch - tp->retrans_stamp is not based on jiffies and can't be compared with icsk->icsk_timeout in the 3rd patch. Fix it. - introduce the 4th patch Changes since v2: - refactor the code to avoid code duplication in the 1st patch - use after() instead of max() in tcp_rtx_probe0_timed_out() Changes since v1: - send 0 rwin ACK for the receive queue empty case when necessary in the 1st patch - send the ACK immediately by using the ICSK_ACK_NOW flag in the 1st patch - consider the case of the connection restart from idle, as Neal comment, in the 3rd patch ==================== Signed-off-by: David S. Miller --- 86f03776f6d58558912bc05158fa75add1886aca