Re: [PATCH 1/2] Documentation: bootconfig: Update boot configuration documentation

[Randy Dunlap]

Hi,
A few more comments for you:

On 2/26/20 11:25 PM, Masami Hiramatsu wrote:
> Update boot configuration documentation.
> 
>  - Not using "config" abbreviation but configuration or description.
>  - Rewrite descriptions of node and its maxinum number.
>  - Add a section of use cases of boot configuration.
>  - Move how to use bootconfig to earlier section.
>  - Fix some typos, indents and format mistakes.
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> ---
>  Documentation/admin-guide/bootconfig.rst |  172 +++++++++++++++++++-----------
>  Documentation/trace/boottime-trace.rst   |    2 
>  2 files changed, 112 insertions(+), 62 deletions(-)
> 
> diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
> index cf2edcd09183..4bac98250bc0 100644
> --- a/Documentation/admin-guide/bootconfig.rst
> +++ b/Documentation/admin-guide/bootconfig.rst
> @@ -11,19 +11,98 @@ Boot Configuration
>  Overview
>  ========
>  
> -The boot configuration expands the current kernel command line to support
> +Boot configuration expands the current kernel command line to support
>  additional key-value data when booting the kernel in an efficient way.

                maybe      s/when/while/

> -This allows administrators to pass a structured-Key config file.
> +This allows administrators to pass a structured-Key configuration file
> +as a way to supplement the kernel command line to pass system boot parameters.
>  
> -Config File Syntax
> -==================
> +Compared with the kernel command line, the boot configuration can provide
> +scalability (up to 32 KiB configurations), readability (structured

This makes it sound like bootconfig supports 32 thousand configurations, but
(I think) it allows up to 32 KiB of configuration data.

> +configuration with comments) and compact expression of option groups.
> +
> +When to Use the Boot Configuration?
> +-----------------------------------
> +
> +The boot configuration supports kernel command line options and init daemon
> +boot options. All sub-keys under "kernel" root key are passed as a part of
> +kernel command line [1]_, and one under "init" root key are passed as a part

                                 ones  {or those}

> +of init command line. For example, ::
> +
> +   root=UUID=8cd79b08-bda0-4b9d-954c-5d5f34b98c82 ro quiet splash console=ttyS0,115200n8 console=tty0
> +
> +This can be written as following boot configuration file.::
> +
> +   kernel {
> +      root = "UUID=8cd79b08-bda0-4b9d-954c-5d5f34b98c82" # nvme0n1p3
> +      ro       # mount rootfs as read only
> +      quiet    # No console log
> +      splash   # show splash image on boot screen
> +      console = "ttyS0,115200n8" # 1st console to serial device
> +      console += tty0            # add 2nd console
> +   }
> +
> +If you think that kernel/init options becomes too long to write in boot-loader
> +configuration file or want to comment on each options, you can use this

                                         on each option,

> +boot configuration. If unsure, you can still continue to use the legacy
> +kernel command line.
> +
> +Also, some subsystem may depend on the boot configuration, and it has own
> +root key. For example, ftrace boot-time tracer uses "ftrace" root key to
> +describe their options [2]_. In this case, you need to use the boot

            its

> +configuration.
> +
> +.. [1] See :ref:`Documentation/admin-guide/kernel-parameters.rst <kernelparameters>`
> +.. [2] See :ref:`Documentation/trace/boottime-trace.rst <boottimetrace>`


-- 
~Randy