Re: [PATCH net-next v2] net: tcp: support to probe tcp receiver OOM

From: Randy Dunlap
Date: Thu Jul 13 2023 - 11:43:21 EST




On 7/13/23 04:24, menglong8.dong@xxxxxxxxx wrote:
> diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
> index 4a010a7cde7f..3de2dce74037 100644
> --- a/Documentation/networking/ip-sysctl.rst
> +++ b/Documentation/networking/ip-sysctl.rst
> @@ -694,6 +694,20 @@ tcp_retries2 - INTEGER
> RFC 1122 recommends at least 100 seconds for the timeout,
> which corresponds to a value of at least 8.
>
> +tcp_oom_retries - INTEGER
> + RTO retransmissions count of the receiver is recognised as OOM.
> + Given a value N, a hypothetical TCP connection will enter probe
> + state if N times RTO retransmissions performed and every
> + retransmission gets a pure ack, who doesn't contain SACK block.

ACK
> +
> + The default value is 0, which means disable the OOM detection.
> + If disabled, skb will be dropped directly, without sending an
> + ACK, when rmem schedule fails. The function is valid only if sack

SACK

> + is enabled.
> +
> + 3 is the suggested value to enable this function. Do't make it

Don't

> + greater than tcp_retries2.

--
~Randy