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

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Date:   Thu, 13 Jul 2023 08:42:53 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     menglong8.dong@...il.com, edumazet@...gle.com, ncardwell@...gle.com
Cc:     davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        corbet@....net, dsahern@...nel.org, kuniyu@...zon.com,
        morleyd@...gle.com, imagedong@...cent.com, mfreemon@...udflare.com,
        mubashirq@...gle.com, netdev@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH net-next v2] net: tcp: support to probe tcp receiver OOM



On 7/13/23 04:24, menglong8.dong@...il.com 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