netdev - Re: [RFC PATCH] Add a sysctl to allow TCP window shrinking in order to honor memory limits

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Message-ID: <20230306140812.17f35658@hermes.local>
Date:   Mon, 6 Mar 2023 14:08:12 -0800
From:   Stephen Hemminger <stephen@...workplumber.org>
To:     Mike Freemon <mfreemon@...udflare.com>
Cc:     netdev@...r.kernel.org
Subject: Re: [RFC PATCH] Add a sysctl to allow TCP window shrinking in order
 to honor memory limits

On Mon,  6 Mar 2023 15:30:58 -0600
Mike Freemon <mfreemon@...udflare.com> wrote:

> +		 * RFC 7323, section 2.4, says there are instances when a retracted
> +		 * window can be offered, and that TCP implementations MUST ensure
> +		 * that they handle a shrinking window, as specified in RFC 1122.
> +		 *
> +		 * This patch implements that functionality, which is enabled by
> +		 * setting the following sysctl.
> +		 *
> +		 * sysctl: net.ipv4.tcp_shrink_window
> +		 *
> +		 * This sysctl changes how the TCP window is calculated.
> +		 *
> +		 * If sysctl tcp_shrink_window is zero (the default value), then the
> +		 * window is never shrunk.
> +		 *
> +		 * If sysctl tcp_shrink_window is non-zero, then the memory limit
> +		 * set by autotuning is honored.  This requires that the TCP window
> +		 * be shrunk ("retracted") as described in RFC 1122.
> +		 *
> +		 * For context and additional information about this patch, see the
> +		 * blog post at TODO

This comment should be reworded such that it can be read at a much
later date with out all the associated context described here.

I.e. Get rid of "this patch part" and the blog post part.

Best to just refer to tcp_shrink_window sysctl and put the details
in the regular documentation spot (Documentation/networking/ip-sysctl.rst).