[PATCH v5 0/1] Documentation: bootconfig: Documentaiton updates

[PATCH v5 0/1] Documentation: bootconfig: Documentaiton updates

[Masami Hiramatsu]

Hi,

Here is the 5th version of the documentation update.
- Elaborated according to Randy's comment.
- Fix some typos.

Thank you,

---

Masami Hiramatsu (1):
      Documentation: bootconfig: Update boot configuration documentation


 Documentation/admin-guide/bootconfig.rst |  201 +++++++++++++++++++-----------
 Documentation/trace/boottime-trace.rst   |    2 
 2 files changed, 131 insertions(+), 72 deletions(-)

--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>

[PATCH v5] Documentation: bootconfig: Update boot configuration documentation

[Masami Hiramatsu]

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@kernel.org>
---
Changes in v5:
 - Elaborate the document.
 - Fix some typos.
Changes in v4:
 - Remove O= option from examples.
Changes in v3:
 - Specify that comments also count in size.
 - Fix a confusing sentence.
 - Add O=<builddir> to make command.
Changes in v2:
 - Fixes additional typos (Thanks Markus and Randy!)
 - Change a section title to "Tree Structured Key".
---
 Documentation/admin-guide/bootconfig.rst |  201 +++++++++++++++++++-----------
 Documentation/trace/boottime-trace.rst   |    2 
 2 files changed, 131 insertions(+), 72 deletions(-)

diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index cf2edcd09183..3bfc9ddf68e1 100644
--- a/Documentation/admin-guide/bootconfig.rst
+++ b/Documentation/admin-guide/bootconfig.rst
@@ -11,25 +11,106 @@ Boot Configuration
 Overview
 ========
 
-The boot configuration expands the current kernel command line to support
-additional key-value data when booting the kernel in an efficient way.
-This allows administrators to pass a structured-Key config file.
+Boot configuration expands the current kernel command line to support
+additional key-value data while booting the kernel in an efficient way.
+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 configuration data including comments), readability
+(structured 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
+the kernel command line [1]_, and ones under "init" root key are passed as
+a part of the init daemon's 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 you want to comment on each option, the boot
+configuration may be suitable. If unsure, you can still continue to use the
+legacy kernel command line.
 
-The boot config syntax is a simple structured key-value. Each key consists
-of dot-connected-words, and key and value are connected by ``=``. The value
-has to be terminated by semi-colon (``;``) or newline (``\n``).
-For array value, array entries are separated by comma (``,``). ::
+Also, some features may depend on the boot configuration, and each such
+feature has its own root key. For example, ftrace boot-time tracer uses
+"ftrace" root key to describe its options [2]_. If you want to use such
+features, you need to enable the boot configuration.
 
-KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
+.. [1] See :ref:`Documentation/admin-guide/kernel-parameters.rst <kernelparameters>`
+.. [2] See :ref:`Documentation/trace/boottime-trace.rst <boottimetrace>`
+
+
+How to Use the Boot Configuration?
+----------------------------------
+
+To enable the boot configuration support on your kernel, it must be built with
+``CONFIG_BOOT_CONFIG=y`` and ``CONFIG_BLK_DEV_INITRD=y``.
+
+Next, you can write a boot configuration file and attach it to initrd image.
+
+The boot configuration file is attached to the end of the initrd (initramfs)
+image file with size, checksum and 12-byte magic word as below.
+
+[initrd][bootconfig][size(u32)][checksum(u32)][#BOOTCONFIG\n]
+
+The Linux kernel decodes the last part of the initrd image in memory to
+get the boot configuration data.
+Because of this "piggyback" method, there is no need to change or
+update the boot loader or the kernel image itself.
+
+To do this operation, Linux kernel provides the "bootconfig" command under
+tools/bootconfig, which allows admin to apply or delete the configuration
+file to/from an initrd image. You can build it by the following command::
+
+ # make -C tools/bootconfig
+
+To add your boot configuration file to an initrd image, run bootconfig as
+below (Old bootconfig is removed automatically if it exists)::
+
+ # tools/bootconfig/bootconfig -a your-config /boot/initrd.img-X.Y.Z
+
+To remove the configuration from the image, you can use the ``-d`` option
+as below::
+
+ # tools/bootconfig/bootconfig -d /boot/initrd.img-X.Y.Z
+
+At last, add ``bootconfig`` on the normal kernel command line to tell the
+kernel to look for the bootconfig at the end of the initrd file. For example::
+
+  GRUB_CMDLINE_LINUX="bootconfig"
+
+
+Boot Configuration Syntax
+=========================
+
+The boot configuration syntax is a simple structured key-value. Each key
+consists of dot-connected-words, and key and value are connected by ``=``.
+The value has to be terminated by semicolon (``;``) or newline (``\n``).
+For an array, its entries are separated by comma (``,``). ::
+
+  KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
 
 Unlike the kernel command line syntax, spaces are OK around the comma and ``=``.
 
 Each key word must contain only alphabets, numbers, dash (``-``) or underscore
 (``_``). And each value only contains printable characters or spaces except
-for delimiters such as semi-colon (``;``), new-line (``\n``), comma (``,``),
+for delimiters such as semicolon (``;``), new-line (``\n``), comma (``,``),
 hash (``#``) and closing brace (``}``).
 
 If you want to use those delimiters in a value, you can use either double-
@@ -39,25 +120,29 @@ you can not escape these quotes.
 There can be a key which doesn't have value or has an empty value. Those keys
 are used for checking if the key exists or not (like a boolean).
 
-Key-Value Syntax
-----------------
+Tree Structured Key
+-------------------
 
-The boot config file syntax allows user to merge partially same word keys
-by brace. For example::
+The user can group identical parent keys together and use braces to list child
+keys under them. For example::
 
  foo.bar.baz = value1
  foo.bar.qux.quux = value2
+ foo.bar.qux.quuz = value3
 
 These can be written also in::
 
  foo.bar {
-    baz = value1
-    qux.quux = value2
+   baz = value1
+   qux {
+      quux = value2
+      quuz = value3
+   }
  }
 
 Or more shorter, written as following::
 
- foo.bar { baz = value1; qux.quux = value2 }
+ foo.bar { baz = value1; qux { quux = value2; quuz = value3 } }
 
 In both styles, same key words are automatically merged when parsing it
 at boot time. So you can append similar trees or key-values.
@@ -80,19 +165,18 @@ you can use ``+=`` operator. For example::
 In this case, the key ``foo`` has ``bar``, ``baz`` and ``qux``.
 
 However, a sub-key and a value can not co-exist under a parent key.
-For example, following config is NOT allowed.::
+For example, the following configuration is NOT allowed.::
 
  foo = value1
- foo.bar = value2 # !ERROR! subkey "bar" and value "value1" can NOT co-exist
+ foo.bar = value2 # !ERROR! sub-key "bar" and value "value1" can NOT co-exist
 
 
 Comments
 --------
 
-The config syntax accepts shell-script style comments. The comments starting
-with hash ("#") until newline ("\n") will be ignored.
-
-::
+The boot configuration accepts shell-script style comments. The comments,
+beginning with hash (``#``) continues until newline (``\n``), will be
+skipped.::
 
  # comment line
  foo = value # value is set to foo.
@@ -100,74 +184,47 @@ with hash ("#") until newline ("\n") will be ignored.
        2, # 2nd element
        3  # 3rd element
 
-This is parsed as below::
+This is parsed as below.::
 
  foo = value
  bar = 1, 2, 3
 
 Note that you can not put a comment between value and delimiter(``,`` or
-``;``). This means following config has a syntax error ::
+``;``). This means the following description has a syntax error. ::
 
- key = 1 # comment
+ key = 1 # !ERROR! comment is not allowed before delimiter
        ,2
 
 
 /proc/bootconfig
 ================
 
-/proc/bootconfig is a user-space interface of the boot config.
+The file /proc/bootconfig is a user-space interface to the configuration
+of system boot parameters.
 Unlike /proc/cmdline, this file shows the key-value style list.
 Each key-value pair is shown in each line with following style::
 
  KEY[.WORDS...] = "[VALUE]"[,"VALUE2"...]
 
 
-Boot Kernel With a Boot Config
-==============================
-
-Since the boot configuration file is loaded with initrd, it will be added
-to the end of the initrd (initramfs) image file with size, checksum and
-12-byte magic word as below.
-
-[initrd][bootconfig][size(u32)][checksum(u32)][#BOOTCONFIG\n]
-
-The Linux kernel decodes the last part of the initrd image in memory to
-get the boot configuration data.
-Because of this "piggyback" method, there is no need to change or
-update the boot loader and the kernel image itself.
-
-To do this operation, Linux kernel provides "bootconfig" command under
-tools/bootconfig, which allows admin to apply or delete the config file
-to/from initrd image. You can build it by the following command::
-
- # make -C tools/bootconfig
-
-To add your boot config file to initrd image, run bootconfig as below
-(Old data is removed automatically if exists)::
-
- # tools/bootconfig/bootconfig -a your-config /boot/initrd.img-X.Y.Z
-
-To remove the config from the image, you can use -d option as below::
-
- # tools/bootconfig/bootconfig -d /boot/initrd.img-X.Y.Z
-
-Then add "bootconfig" on the normal kernel command line to tell the
-kernel to look for the bootconfig at the end of the initrd file.
-
 Config File Limitation
 ======================
 
-Currently the maximum config size size is 32KB and the total key-words (not
-key-value entries) must be under 1024 nodes.
-Note: this is not the number of entries but nodes, an entry must consume
-more than 2 nodes (a key-word and a value). So theoretically, it will be
-up to 512 key-value pairs. If keys contains 3 words in average, it can
-contain 256 key-value pairs. In most cases, the number of config items
-will be under 100 entries and smaller than 8KB, so it would be enough.
-If the node number exceeds 1024, parser returns an error even if the file
-size is smaller than 32KB.
-Anyway, since bootconfig command verifies it when appending a boot config
-to initrd image, user can notice it before boot.
+Currently the maximum configuration file size (including comments) is 32 KiB
+and the total number of key-words and values must be under 1024 nodes.
+(Note: Each key consists of words separated by dot, and value also consists
+of values separated by comma. Here, each word and each value is generally
+called a "node".)
+
+Theoretically, it will be up to 512 key-value pairs. If keys contain 3
+words in average, it can contain 256 key-value pairs. In most cases,
+the number of configuration items will be under 100 entries and smaller
+than 8 KiB, so it would be enough.
+If the node number exceeds 1024, the parser returns an error even if the
+file size is smaller than 32 KiB.
+Anyway, since the bootconfig command verifies it when appending a boot
+configuration to an initrd image, the user needs to fix any errors
+before boot.
 
 
 Bootconfig APIs
@@ -206,7 +263,7 @@ or get the named array under prefix as below::
 This accesses a value of "key.prefix.option" and an array of
 "key.prefix.array-option".
 
-Locking is not needed, since after initialization, the config becomes
+Locking is not needed, since after initialization, the configuration becomes
 read-only. All data and keys must be copied if you need to modify it.
 
 
diff --git a/Documentation/trace/boottime-trace.rst b/Documentation/trace/boottime-trace.rst
index dcb390075ca1..e6cbe22361e9 100644
--- a/Documentation/trace/boottime-trace.rst
+++ b/Documentation/trace/boottime-trace.rst
@@ -1,5 +1,7 @@
 .. SPDX-License-Identifier: GPL-2.0
 
+.. _boottimetrace:
+
 =================
 Boot-time tracing
 =================

Re: [PATCH v5] Documentation: bootconfig: Update boot configuration documentation

[Randy Dunlap]

On 3/4/20 10:44 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@kernel.org>

Hi Masami,

I swear that I am not trying to cause another version...

> ---
> Changes in v5:
>  - Elaborate the document.
>  - Fix some typos.
> Changes in v4:
>  - Remove O= option from examples.
> Changes in v3:
>  - Specify that comments also count in size.
>  - Fix a confusing sentence.
>  - Add O=<builddir> to make command.
> Changes in v2:
>  - Fixes additional typos (Thanks Markus and Randy!)
>  - Change a section title to "Tree Structured Key".
> ---
>  Documentation/admin-guide/bootconfig.rst |  201 +++++++++++++++++++-----------
>  Documentation/trace/boottime-trace.rst   |    2 
>  2 files changed, 131 insertions(+), 72 deletions(-)
> 
> diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
> index cf2edcd09183..3bfc9ddf68e1 100644
> --- a/Documentation/admin-guide/bootconfig.rst
> +++ b/Documentation/admin-guide/bootconfig.rst
> @@ -11,25 +11,106 @@ Boot Configuration

> +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
> +the kernel command line [1]_, and ones under "init" root key are passed as
> +a part of the init daemon's 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

                                         become

> +configuration file or you want to comment on each option, the boot
> +configuration may be suitable. If unsure, you can still continue to use the
> +legacy kernel command line.


> +Boot Configuration Syntax
> +=========================
> +
> +The boot configuration syntax is a simple structured key-value. Each key
> +consists of dot-connected-words, and key and value are connected by ``=``.
> +The value has to be terminated by semicolon (``;``) or newline (``\n``).
> +For an array, its entries are separated by comma (``,``). ::
> +
> +  KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
>  
>  Unlike the kernel command line syntax, spaces are OK around the comma and ``=``.
>  
>  Each key word must contain only alphabets, numbers, dash (``-``) or underscore
>  (``_``). And each value only contains printable characters or spaces except
> -for delimiters such as semi-colon (``;``), new-line (``\n``), comma (``,``),
> +for delimiters such as semicolon (``;``), new-line (``\n``), comma (``,``),

            usually called:                  newline

>  hash (``#``) and closing brace (``}``).
>  
>  If you want to use those delimiters in a value, you can use either double-


>  Comments
>  --------
>  
> -The config syntax accepts shell-script style comments. The comments starting
> -with hash ("#") until newline ("\n") will be ignored.
> -
> -::
> +The boot configuration accepts shell-script style comments. The comments,
> +beginning with hash (``#``) continues until newline (``\n``), will be

                               and continuing until newline

> +skipped.::
>  
>   # comment line
>   foo = value # value is set to foo.


Reviewed-by: Randy Dunlap <rdunlap@infradead.org>

thanks.
-- 
~Randy

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>

How does this feedback fit to known concerns around the discussed wordings?

Regards,
Markus

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Randy Dunlap]

On 3/5/20 1:33 AM, Markus Elfring wrote:
>> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
> 
> How does this feedback fit to known concerns around the discussed wordings?

As far as I am concerned, it means that the documentation is
sufficiently good enough to be useful and not difficult to read.

It does not mean that it's perfect. Patches can still be made to it.

-- 
~Randy

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>> How does this feedback fit to known concerns around the discussed wordings?
>
> As far as I am concerned, it means that the documentation is
> sufficiently good enough to be useful and not difficult to read.

Would you like to add anything to my previous review comments
(besides simple typo adjustments)?


> It does not mean that it's perfect. Patches can still be made to it.

I hope that corresponding agreements will be achieved for
further improvements.

Regards,
Markus

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Randy Dunlap]

On 3/5/20 9:30 AM, Markus Elfring wrote:
>>> How does this feedback fit to known concerns around the discussed wordings?
>>
>> As far as I am concerned, it means that the documentation is
>> sufficiently good enough to be useful and not difficult to read.
> 
> Would you like to add anything to my previous review comments
> (besides simple typo adjustments)?

If you would (could) be more concrete (or discrete) in your suggestions,
I would be glad to comment on them.

> 
> 
>> It does not mean that it's perfect. Patches can still be made to it.
> 
> I hope that corresponding agreements will be achieved for
> further improvements.


-- 
~Randy

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

> If you would (could) be more concrete (or discrete) in your suggestions,
> I would be glad to comment on them.

Does this view indicate any communication difficulties?

Which of the possibly unanswered issues do you find not concrete enough so far?

Regards,
Markus

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Randy Dunlap]

On 3/5/20 9:56 AM, Markus Elfring wrote:
>> If you would (could) be more concrete (or discrete) in your suggestions,
>> I would be glad to comment on them.
> 
> Does this view indicate any communication difficulties?

Probably.

> Which of the possibly unanswered issues do you find not concrete enough so far?

e.g.:
>>>  Will the clarification become more constructive for remaining challenges?


-- 
~Randy

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>>> If you would (could) be more concrete (or discrete) in your suggestions,
>>> I would be glad to comment on them.
>>
>> Does this view indicate any communication difficulties?
>
> Probably.
>
>> Which of the possibly unanswered issues do you find not concrete enough so far?
>
> e.g.:
>>>>  Will the clarification become more constructive for remaining challenges?

Do you expect that known open issues need to be repeated for each patch revision?

How do you think about the desired tracking of bug reports
also for this software?

Regards,
Markus

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Randy Dunlap]

On 3/5/20 10:43 AM, Markus Elfring wrote:
>>>> If you would (could) be more concrete (or discrete) in your suggestions,
>>>> I would be glad to comment on them.
>>>
>>> Does this view indicate any communication difficulties?
>>
>> Probably.
>>
>>> Which of the possibly unanswered issues do you find not concrete enough so far?
>>
>> e.g.:
>>>>>  Will the clarification become more constructive for remaining challenges?
> 
> Do you expect that known open issues need to be repeated for each patch revision?

Ideally not, but not very much is ideal.

IOW, it is sometimes required (if one cares enough; sometimes
one just gives up).

> How do you think about the desired tracking of bug reports
> also for this software?

I expect that more users will begin to use it and report problems
as they see fit.  They can use mailing list(s) and/or
bugzilla.kernel.org.  I'm not terribly concerned about it.
Masami seems to be responsive.

thanks.
-- 
~Randy

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>>>> Which of the possibly unanswered issues do you find not concrete enough so far?
>>>
>>> e.g.:
>>>>>>  Will the clarification become more constructive for remaining challenges?
>>
>> Do you expect that known open issues need to be repeated for each patch revision?
>
> Ideally not, but not very much is ideal.

Did you notice any aspects where I would be still looking for more helpful answers?


> IOW, it is sometimes required (if one cares enough; sometimes
> one just gives up).

I find this communication detail unfortunate occasionally.


>> How do you think about the desired tracking of bug reports
>> also for this software?
…
> Masami seems to be responsive.

The involved contributors show different response delays, don't they?

Regards,
Markus

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Randy Dunlap]

On 3/5/20 11:06 AM, Markus Elfring wrote:
>>>>> Which of the possibly unanswered issues do you find not concrete enough so far?
>>>>
>>>> e.g.:
>>>>>>>  Will the clarification become more constructive for remaining challenges?
>>>
>>> Do you expect that known open issues need to be repeated for each patch revision?
>>
>> Ideally not, but not very much is ideal.
> 
> Did you notice any aspects where I would be still looking for more helpful answers?

Sorry, I haven't been tracking all of the email Q&A/response/replies
all that carefully.

> 
>> IOW, it is sometimes required (if one cares enough; sometimes
>> one just gives up).
> 
> I find this communication detail unfortunate occasionally.

Sure. I do too.

> 
>>> How do you think about the desired tracking of bug reports
>>> also for this software?
> …
>> Masami seems to be responsive.
> 
> The involved contributors show different response delays, don't they?

That's always the case, in any of the Linux subsystems that I have
been involved with.

-- 
~Randy

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>> The involved contributors show different response delays, don't they?
>
> That's always the case, in any of the Linux subsystems that I have
> been involved with.

Some delays are usual.

But I can occasionally get the concern that specific constructive feedback
would be overlooked or intentionally ignored.
Such a view would be unfortunate if I would like to achieve further improvements
also around this software.

Regards,
Markus

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Steven Rostedt]

On Thu, 5 Mar 2020 20:06:47 +0100
Markus Elfring <Markus.Elfring@web.de> wrote:

> >>>> Which of the possibly unanswered issues do you find not concrete enough so far?  
> >>>
> >>> e.g.:  
> >>>>>>  Will the clarification become more constructive for remaining challenges?  
> >>
> >> Do you expect that known open issues need to be repeated for each patch revision?  
> >
> > Ideally not, but not very much is ideal.  
> 
> Did you notice any aspects where I would be still looking for more helpful answers?

What does that even mean?

> 
> 
> > IOW, it is sometimes required (if one cares enough; sometimes
> > one just gives up).  
> 
> I find this communication detail unfortunate occasionally.

Well, it's better than slamming one's head into their desk.

> 
> 
> >> How do you think about the desired tracking of bug reports
> >> also for this software?  
> …
> > Masami seems to be responsive.  
> 
> The involved contributors show different response delays, don't they?
> 

Of course! Masami is in Japan, and is probably sleeping right now. That's
what happens when you work in a global environment.

-- Steve

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>>> Masami seems to be responsive.
>>
>> The involved contributors show different response delays, don't they?
>
> Of course! Masami is in Japan, and is probably sleeping right now.

I am not so concerned about the global distribution of contributors.


> That's what happens when you work in a global environment.

I am used to this fact for years.

I became more concerned about information which was not directly provided
in patch change logs (according to my software development expectations).

Regards,
Markus

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Steven Rostedt]

On Thu, 5 Mar 2020 21:26:40 +0100
Markus Elfring <Markus.Elfring@web.de> wrote:

> >>> Masami seems to be responsive.  
> >>
> >> The involved contributors show different response delays, don't they?  
> >
> > Of course! Masami is in Japan, and is probably sleeping right now.  
> 
> I am not so concerned about the global distribution of contributors.
> 
> 
> > That's what happens when you work in a global environment.  
> 
> I am used to this fact for years.
> 
> I became more concerned about information which was not directly provided
> in patch change logs (according to my software development expectations).
> 

Well, the information added was enough for my own software development
expectations, and that's all I care about.

-- Steve

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Steven Rostedt]

On Thu, 5 Mar 2020 19:43:59 +0100
Markus Elfring <Markus.Elfring@web.de> wrote:

> >>> If you would (could) be more concrete (or discrete) in your suggestions,
> >>> I would be glad to comment on them.  
> >>
> >> Does this view indicate any communication difficulties?  
> >
> > Probably.
> >  
> >> Which of the possibly unanswered issues do you find not concrete enough so far?  
> >
> > e.g.:  
> >>>>  Will the clarification become more constructive for remaining challenges?  
> 
> Do you expect that known open issues need to be repeated for each patch revision?

I'm clueless about what you are talking about. Yes there's communication
difficulties.

> 
> How do you think about the desired tracking of bug reports
> also for this software?

What does that statement have to do with this patch series????


-- Steve

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>>>> Which of the possibly unanswered issues do you find not concrete enough so far?
>>>
>>> e.g.:
>>>>>>  Will the clarification become more constructive for remaining challenges?
>>
>> Do you expect that known open issues need to be repeated for each patch revision?
>
> I'm clueless about what you are talking about.

I suggest to take another look at review comments for previous patch versions.


> Yes there's communication difficulties.

I hope that we can reduce them somehow.


>> How do you think about the desired tracking of bug reports
>> also for this software?
>
> What does that statement have to do with this patch series????

Do you identify any feedback as a bug report (or clarification request) here?

Regards,
Markus

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Steven Rostedt]

On Thu, 5 Mar 2020 20:14:00 +0100
Markus Elfring <Markus.Elfring@web.de> wrote:

> >>>> Which of the possibly unanswered issues do you find not concrete enough so far?  
> >>>
> >>> e.g.:  
> >>>>>>  Will the clarification become more constructive for remaining challenges?  
> >>
> >> Do you expect that known open issues need to be repeated for each patch revision?  
> >
> > I'm clueless about what you are talking about.  
> 
> I suggest to take another look at review comments for previous patch versions.

I have, and I believe Masami has satisfactory addressed them, if they
needed addressing.

> 
> 
> > Yes there's communication difficulties.  
> 
> I hope that we can reduce them somehow.

Then please be more specific in your correspondence.

> 
> 
> >> How do you think about the desired tracking of bug reports
> >> also for this software?  
> >
> > What does that statement have to do with this patch series????  
> 
> Do you identify any feedback as a bug report (or clarification request) here?

I still don't have the foggiest clue what you are talking about. What bug
are you reporting?

-- Steve

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>> I suggest to take another look at review comments for previous patch versions.
>
> I have, and I believe Masami has satisfactory addressed them,

I agree to parts of the shown software evolution.


> if they needed addressing.

Remaining issues will eventually be clarified under other circumstances.


>> Do you identify any feedback as a bug report (or clarification request) here?
>
> I still don't have the foggiest clue what you are talking about.

It seems that a few reminders can help here.


> What bug are you reporting?

Examples:

* Another typo
  “… contain only alphabets, …”
  https://lore.kernel.org/linux-doc/967d6fee-e0cd-c53f-c1f6-b367a979762c@web.de/
  https://lkml.org/lkml/2020/3/5/247

* Use case explanation
  https://lore.kernel.org/linux-doc/f3c51b0a-2a55-6523-96e2-4f9ef0635d9f@web.de/
  https://lkml.org/lkml/2020/3/5/429

* Challenges for the safe application of key hierarchies
  “kernel.ftrace”?
  https://lore.kernel.org/linux-doc/c4a0bc10-a38b-6ea9-e125-7a37f667e61a@web.de/
  https://lkml.org/lkml/2020/2/28/363

* Feature request for syntax description
  https://lore.kernel.org/linux-doc/2390b729-1b0b-26b5-66bc-92e40e3467b1@web.de/
  https://lkml.org/lkml/2020/2/27/1869


Regards,
Markus

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Steven Rostedt]

On Thu, 5 Mar 2020 21:10:21 +0100
Markus Elfring <Markus.Elfring@web.de> wrote:

> >> I suggest to take another look at review comments for previous patch versions.  
> >
> > I have, and I believe Masami has satisfactory addressed them,  
> 
> I agree to parts of the shown software evolution.
> 
> 
> > if they needed addressing.  
> 
> Remaining issues will eventually be clarified under other circumstances.
> 
> 
> >> Do you identify any feedback as a bug report (or clarification request) here?  
> >
> > I still don't have the foggiest clue what you are talking about.  
> 
> It seems that a few reminders can help here.
> 
> 
> > What bug are you reporting?  
> 
> Examples:
> 
> * Another typo
>   “… contain only alphabets, …”
>   https://lore.kernel.org/linux-doc/967d6fee-e0cd-c53f-c1f6-b367a979762c@web.de/
>   https://lkml.org/lkml/2020/3/5/247

Legitimate but not critical.

> 
> * Use case explanation
>   https://lore.kernel.org/linux-doc/f3c51b0a-2a55-6523-96e2-4f9ef0635d9f@web.de/
>   https://lkml.org/lkml/2020/3/5/429

I believe what Masami has is sufficient.

> 
> * Challenges for the safe application of key hierarchies
>   “kernel.ftrace”?
>   https://lore.kernel.org/linux-doc/c4a0bc10-a38b-6ea9-e125-7a37f667e61a@web.de/
>   https://lkml.org/lkml/2020/2/28/363

Again, what Masami has is sufficient.

> 
> * Feature request for syntax description
>   https://lore.kernel.org/linux-doc/2390b729-1b0b-26b5-66bc-92e40e3467b1@web.de/
>   https://lkml.org/lkml/2020/2/27/1869
> 

Masami's reply to you was sufficient.

Of your examples, only one do I see can be applied, but is just a minor
change in wording.

I don't know where you are going with this, and unless you plan on
submitting patches, I think this document is complete as is.

-- Steve

Re: [v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>>> What bug are you reporting?
>>
>> Examples:
>>
>> * Another typo
>>   “… contain only alphabets, …”
>>   https://lore.kernel.org/linux-doc/967d6fee-e0cd-c53f-c1f6-b367a979762c@web.de/
>>   https://lkml.org/lkml/2020/3/5/247
>
> Legitimate but not critical.

Thanks for such a view.

It might be that less simple update candidates were left over now.



>> * Use case explanation
>>   https://lore.kernel.org/linux-doc/f3c51b0a-2a55-6523-96e2-4f9ef0635d9f@web.de/
>>   https://lkml.org/lkml/2020/3/5/429
>
> I believe what Masami has is sufficient.

I got an other impression.

An other document contains background information like the following.

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/trace/boottime-trace.rst?id=b8381ce7aa8ef1ab5a79bf710508e504c494acf7
“…
Since kernel command line is not enough to control these complex features,
this uses bootconfig file to describe tracing feature programming.
…”



>> * Challenges for the safe application of key hierarchies
>>   “kernel.ftrace”?
>>   https://lore.kernel.org/linux-doc/c4a0bc10-a38b-6ea9-e125-7a37f667e61a@web.de/
>>   https://lkml.org/lkml/2020/2/28/363
>
> Again, what Masami has is sufficient.

I would appreciate further clarification also in this area.


>> * Feature request for syntax description
>>   https://lore.kernel.org/linux-doc/2390b729-1b0b-26b5-66bc-92e40e3467b1@web.de/
>>   https://lkml.org/lkml/2020/2/27/1869
>
> Masami's reply to you was sufficient.

Yes (in principle).

But I hope to achieve collateral evolution here, too.


> Of your examples, only one do I see can be applied, but is just a minor
> change in wording.

I am trying again to resolve disagreements somehow.


> I don't know where you are going with this, and unless you plan on
> submitting patches, I think this document is complete as is.

I hope also to influence the software development attention another bit.

Regards,
Markus

Re: [PATCH v5] Documentation: bootconfig: Update boot configuration documentation

[Masami Hiramatsu]

On Wed, 4 Mar 2020 23:01:21 -0800
Randy Dunlap <rdunlap@infradead.org> wrote:

> On 3/4/20 10:44 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@kernel.org>
> 
> Hi Masami,
> 
> I swear that I am not trying to cause another version...

Oh, no problem. I'll go along with your reviews.

> 
> > ---
> > Changes in v5:
> >  - Elaborate the document.
> >  - Fix some typos.
> > Changes in v4:
> >  - Remove O= option from examples.
> > Changes in v3:
> >  - Specify that comments also count in size.
> >  - Fix a confusing sentence.
> >  - Add O=<builddir> to make command.
> > Changes in v2:
> >  - Fixes additional typos (Thanks Markus and Randy!)
> >  - Change a section title to "Tree Structured Key".
> > ---
> >  Documentation/admin-guide/bootconfig.rst |  201 +++++++++++++++++++-----------
> >  Documentation/trace/boottime-trace.rst   |    2 
> >  2 files changed, 131 insertions(+), 72 deletions(-)
> > 
> > diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
> > index cf2edcd09183..3bfc9ddf68e1 100644
> > --- a/Documentation/admin-guide/bootconfig.rst
> > +++ b/Documentation/admin-guide/bootconfig.rst
> > @@ -11,25 +11,106 @@ Boot Configuration
> 
> > +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
> > +the kernel command line [1]_, and ones under "init" root key are passed as
> > +a part of the init daemon's 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
> 
>                                          become

OK.

> 
> > +configuration file or you want to comment on each option, the boot
> > +configuration may be suitable. If unsure, you can still continue to use the
> > +legacy kernel command line.
> 
> 
> > +Boot Configuration Syntax
> > +=========================
> > +
> > +The boot configuration syntax is a simple structured key-value. Each key
> > +consists of dot-connected-words, and key and value are connected by ``=``.
> > +The value has to be terminated by semicolon (``;``) or newline (``\n``).
> > +For an array, its entries are separated by comma (``,``). ::
> > +
> > +  KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
> >  
> >  Unlike the kernel command line syntax, spaces are OK around the comma and ``=``.
> >  
> >  Each key word must contain only alphabets, numbers, dash (``-``) or underscore
> >  (``_``). And each value only contains printable characters or spaces except
> > -for delimiters such as semi-colon (``;``), new-line (``\n``), comma (``,``),
> > +for delimiters such as semicolon (``;``), new-line (``\n``), comma (``,``),
> 
>             usually called:                  newline

Yeah, I wonder why I have written so...

> 
> >  hash (``#``) and closing brace (``}``).
> >  
> >  If you want to use those delimiters in a value, you can use either double-
> 
> 
> >  Comments
> >  --------
> >  
> > -The config syntax accepts shell-script style comments. The comments starting
> > -with hash ("#") until newline ("\n") will be ignored.
> > -
> > -::
> > +The boot configuration accepts shell-script style comments. The comments,
> > +beginning with hash (``#``) continues until newline (``\n``), will be
> 
>                                and continuing until newline

OK.

> 
> > +skipped.::
> >  
> >   # comment line
> >   foo = value # value is set to foo.
> 
> 
> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>

Thank you!

-- 
Masami Hiramatsu <mhiramat@kernel.org>

[PATCH v5.1] Documentation: bootconfig: Update boot configuration documentation

[Masami Hiramatsu]

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@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
---
Changes in v5.1:
 - Fix some mistakes (Thanks Randy!)
Changes in v5:
 - Elaborate the document.
 - Fix some typos.
Changes in v4:
 - Remove O= option from examples.
Changes in v3:
 - Specify that comments also count in size.
 - Fix a confusing sentence.
 - Add O=<builddir> to make command.
Changes in v2:
 - Fixes additional typos (Thanks Markus and Randy!)
 - Change a section title to "Tree Structured Key".
---
 Documentation/admin-guide/bootconfig.rst |  201 +++++++++++++++++++-----------
 Documentation/trace/boottime-trace.rst   |    2 
 2 files changed, 131 insertions(+), 72 deletions(-)

diff --git a/Documentation/admin-guide/bootconfig.rst b/Documentation/admin-guide/bootconfig.rst
index cf2edcd09183..e620d525b73f 100644
--- a/Documentation/admin-guide/bootconfig.rst
+++ b/Documentation/admin-guide/bootconfig.rst
@@ -11,25 +11,106 @@ Boot Configuration
 Overview
 ========
 
-The boot configuration expands the current kernel command line to support
-additional key-value data when booting the kernel in an efficient way.
-This allows administrators to pass a structured-Key config file.
+Boot configuration expands the current kernel command line to support
+additional key-value data while booting the kernel in an efficient way.
+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 configuration data including comments), readability
+(structured 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
+the kernel command line [1]_, and ones under "init" root key are passed as
+a part of the init daemon's 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 become too long to write in boot-loader
+configuration file or you want to comment on each option, the boot
+configuration may be suitable. If unsure, you can still continue to use the
+legacy kernel command line.
 
-The boot config syntax is a simple structured key-value. Each key consists
-of dot-connected-words, and key and value are connected by ``=``. The value
-has to be terminated by semi-colon (``;``) or newline (``\n``).
-For array value, array entries are separated by comma (``,``). ::
+Also, some features may depend on the boot configuration, and each such
+feature has its own root key. For example, ftrace boot-time tracer uses
+"ftrace" root key to describe its options [2]_. If you want to use such
+features, you need to enable the boot configuration.
 
-KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
+.. [1] See :ref:`Documentation/admin-guide/kernel-parameters.rst <kernelparameters>`
+.. [2] See :ref:`Documentation/trace/boottime-trace.rst <boottimetrace>`
+
+
+How to Use the Boot Configuration?
+----------------------------------
+
+To enable the boot configuration support on your kernel, it must be built with
+``CONFIG_BOOT_CONFIG=y`` and ``CONFIG_BLK_DEV_INITRD=y``.
+
+Next, you can write a boot configuration file and attach it to initrd image.
+
+The boot configuration file is attached to the end of the initrd (initramfs)
+image file with size, checksum and 12-byte magic word as below.
+
+[initrd][bootconfig][size(u32)][checksum(u32)][#BOOTCONFIG\n]
+
+The Linux kernel decodes the last part of the initrd image in memory to
+get the boot configuration data.
+Because of this "piggyback" method, there is no need to change or
+update the boot loader or the kernel image itself.
+
+To do this operation, Linux kernel provides the "bootconfig" command under
+tools/bootconfig, which allows admin to apply or delete the configuration
+file to/from an initrd image. You can build it by the following command::
+
+ # make -C tools/bootconfig
+
+To add your boot configuration file to an initrd image, run bootconfig as
+below (Old bootconfig is removed automatically if it exists)::
+
+ # tools/bootconfig/bootconfig -a your-config /boot/initrd.img-X.Y.Z
+
+To remove the configuration from the image, you can use the ``-d`` option
+as below::
+
+ # tools/bootconfig/bootconfig -d /boot/initrd.img-X.Y.Z
+
+At last, add ``bootconfig`` on the normal kernel command line to tell the
+kernel to look for the bootconfig at the end of the initrd file. For example::
+
+  GRUB_CMDLINE_LINUX="bootconfig"
+
+
+Boot Configuration Syntax
+=========================
+
+The boot configuration syntax is a simple structured key-value. Each key
+consists of dot-connected-words, and key and value are connected by ``=``.
+The value has to be terminated by semicolon (``;``) or newline (``\n``).
+For an array, its entries are separated by comma (``,``). ::
+
+  KEY[.WORD[...]] = VALUE[, VALUE2[...]][;]
 
 Unlike the kernel command line syntax, spaces are OK around the comma and ``=``.
 
 Each key word must contain only alphabets, numbers, dash (``-``) or underscore
 (``_``). And each value only contains printable characters or spaces except
-for delimiters such as semi-colon (``;``), new-line (``\n``), comma (``,``),
+for delimiters such as semicolon (``;``), newline (``\n``), comma (``,``),
 hash (``#``) and closing brace (``}``).
 
 If you want to use those delimiters in a value, you can use either double-
@@ -39,25 +120,29 @@ you can not escape these quotes.
 There can be a key which doesn't have value or has an empty value. Those keys
 are used for checking if the key exists or not (like a boolean).
 
-Key-Value Syntax
-----------------
+Tree Structured Key
+-------------------
 
-The boot config file syntax allows user to merge partially same word keys
-by brace. For example::
+The user can group identical parent keys together and use braces to list child
+keys under them. For example::
 
  foo.bar.baz = value1
  foo.bar.qux.quux = value2
+ foo.bar.qux.quuz = value3
 
 These can be written also in::
 
  foo.bar {
-    baz = value1
-    qux.quux = value2
+   baz = value1
+   qux {
+      quux = value2
+      quuz = value3
+   }
  }
 
 Or more shorter, written as following::
 
- foo.bar { baz = value1; qux.quux = value2 }
+ foo.bar { baz = value1; qux { quux = value2; quuz = value3 } }
 
 In both styles, same key words are automatically merged when parsing it
 at boot time. So you can append similar trees or key-values.
@@ -80,19 +165,18 @@ you can use ``+=`` operator. For example::
 In this case, the key ``foo`` has ``bar``, ``baz`` and ``qux``.
 
 However, a sub-key and a value can not co-exist under a parent key.
-For example, following config is NOT allowed.::
+For example, the following configuration is NOT allowed.::
 
  foo = value1
- foo.bar = value2 # !ERROR! subkey "bar" and value "value1" can NOT co-exist
+ foo.bar = value2 # !ERROR! sub-key "bar" and value "value1" can NOT co-exist
 
 
 Comments
 --------
 
-The config syntax accepts shell-script style comments. The comments starting
-with hash ("#") until newline ("\n") will be ignored.
-
-::
+The boot configuration accepts shell-script style comments. The comments,
+beginning with hash (``#``) and continuing until newline (``\n``), will be
+skipped.::
 
  # comment line
  foo = value # value is set to foo.
@@ -100,74 +184,47 @@ with hash ("#") until newline ("\n") will be ignored.
        2, # 2nd element
        3  # 3rd element
 
-This is parsed as below::
+This is parsed as below.::
 
  foo = value
  bar = 1, 2, 3
 
 Note that you can not put a comment between value and delimiter(``,`` or
-``;``). This means following config has a syntax error ::
+``;``). This means the following description has a syntax error. ::
 
- key = 1 # comment
+ key = 1 # !ERROR! comment is not allowed before delimiter
        ,2
 
 
 /proc/bootconfig
 ================
 
-/proc/bootconfig is a user-space interface of the boot config.
+The file /proc/bootconfig is a user-space interface to the configuration
+of system boot parameters.
 Unlike /proc/cmdline, this file shows the key-value style list.
 Each key-value pair is shown in each line with following style::
 
  KEY[.WORDS...] = "[VALUE]"[,"VALUE2"...]
 
 
-Boot Kernel With a Boot Config
-==============================
-
-Since the boot configuration file is loaded with initrd, it will be added
-to the end of the initrd (initramfs) image file with size, checksum and
-12-byte magic word as below.
-
-[initrd][bootconfig][size(u32)][checksum(u32)][#BOOTCONFIG\n]
-
-The Linux kernel decodes the last part of the initrd image in memory to
-get the boot configuration data.
-Because of this "piggyback" method, there is no need to change or
-update the boot loader and the kernel image itself.
-
-To do this operation, Linux kernel provides "bootconfig" command under
-tools/bootconfig, which allows admin to apply or delete the config file
-to/from initrd image. You can build it by the following command::
-
- # make -C tools/bootconfig
-
-To add your boot config file to initrd image, run bootconfig as below
-(Old data is removed automatically if exists)::
-
- # tools/bootconfig/bootconfig -a your-config /boot/initrd.img-X.Y.Z
-
-To remove the config from the image, you can use -d option as below::
-
- # tools/bootconfig/bootconfig -d /boot/initrd.img-X.Y.Z
-
-Then add "bootconfig" on the normal kernel command line to tell the
-kernel to look for the bootconfig at the end of the initrd file.
-
 Config File Limitation
 ======================
 
-Currently the maximum config size size is 32KB and the total key-words (not
-key-value entries) must be under 1024 nodes.
-Note: this is not the number of entries but nodes, an entry must consume
-more than 2 nodes (a key-word and a value). So theoretically, it will be
-up to 512 key-value pairs. If keys contains 3 words in average, it can
-contain 256 key-value pairs. In most cases, the number of config items
-will be under 100 entries and smaller than 8KB, so it would be enough.
-If the node number exceeds 1024, parser returns an error even if the file
-size is smaller than 32KB.
-Anyway, since bootconfig command verifies it when appending a boot config
-to initrd image, user can notice it before boot.
+Currently the maximum configuration file size (including comments) is 32 KiB
+and the total number of key-words and values must be under 1024 nodes.
+(Note: Each key consists of words separated by dot, and value also consists
+of values separated by comma. Here, each word and each value is generally
+called a "node".)
+
+Theoretically, it will be up to 512 key-value pairs. If keys contain 3
+words in average, it can contain 256 key-value pairs. In most cases,
+the number of configuration items will be under 100 entries and smaller
+than 8 KiB, so it would be enough.
+If the node number exceeds 1024, the parser returns an error even if the
+file size is smaller than 32 KiB.
+Anyway, since the bootconfig command verifies it when appending a boot
+configuration to an initrd image, the user needs to fix any errors
+before boot.
 
 
 Bootconfig APIs
@@ -206,7 +263,7 @@ or get the named array under prefix as below::
 This accesses a value of "key.prefix.option" and an array of
 "key.prefix.array-option".
 
-Locking is not needed, since after initialization, the config becomes
+Locking is not needed, since after initialization, the configuration becomes
 read-only. All data and keys must be copied if you need to modify it.
 
 
diff --git a/Documentation/trace/boottime-trace.rst b/Documentation/trace/boottime-trace.rst
index dcb390075ca1..e6cbe22361e9 100644
--- a/Documentation/trace/boottime-trace.rst
+++ b/Documentation/trace/boottime-trace.rst
@@ -1,5 +1,7 @@
 .. SPDX-License-Identifier: GPL-2.0
 
+.. _boottimetrace:
+
 =================
 Boot-time tracing
 =================

Re: [PATCH v5.1] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

> Changes in v5.1:
>  - Fix some mistakes (Thanks Randy!)

Do you need any more reminders for remaining update candidates?


…
> +++ b/Documentation/admin-guide/bootconfig.rst
…
> +If you think that kernel/init options become too long to write in boot-loader
> +configuration file or you want to comment on each option, the boot
> +configuration may be suitable. …

Would you like to specify any settings in the boot configuration file
because the provided storage capacity would be too limited by the kernel command line?

Regards,
Markus

Re: [PATCH v5.1] Documentation: bootconfig: Update boot configuration documentation

[Masami Hiramatsu]

On Thu, 5 Mar 2020 15:00:14 +0100
Markus Elfring <Markus.Elfring@web.de> wrote:

> > Changes in v5.1:
> >  - Fix some mistakes (Thanks Randy!)
> 
> Do you need any more reminders for remaining update candidates?

Hmm, no, I don't need it any more at this point. This is good enough.

If you think you have "any more" update candidates, feel free to make
an update "patch" and send to us. That will be the next step.

> …
> > +++ b/Documentation/admin-guide/bootconfig.rst
> …
> > +If you think that kernel/init options become too long to write in boot-loader
> > +configuration file or you want to comment on each option, the boot
> > +configuration may be suitable. …
> 
> Would you like to specify any settings in the boot configuration file
> because the provided storage capacity would be too limited by the kernel command line?

Yes.

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [PATCH v5.1] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

> If you think you have "any more" update candidates, feel free to make
> an update "patch" and send to us.

I pointed a few change possibilities out already.


> That will be the next step.

I got the impression that we are in the process of constructing another patch together
which will fix known wording weaknesses.


By the way:
I wonder about the shown version identifier.
Will the patch numbering need also further considerations?


>> …
>>> +++ b/Documentation/admin-guide/bootconfig.rst
>> …
>>> +If you think that kernel/init options become too long to write in boot-loader
>>> +configuration file or you want to comment on each option, the boot
>>> +configuration may be suitable. …
>>
>> Would you like to specify any settings in the boot configuration file
>> because the provided storage capacity would be too limited by the kernel command line?
>
> Yes.

How will affected places be improved after such an agreement?

Regards,
Markus

Re: [PATCH v5.1] Documentation: bootconfig: Update boot configuration documentation

[Masami Hiramatsu]

On Fri, 6 Mar 2020 10:34:30 +0100
Markus Elfring <Markus.Elfring@web.de> wrote:

> > If you think you have "any more" update candidates, feel free to make
> > an update "patch" and send to us.
> 
> I pointed a few change possibilities out already.

I can not respond to requests only for possibility.

> > That will be the next step.
> 
> I got the impression that we are in the process of constructing another patch together
> which will fix known wording weaknesses.

Would you mean the broken EBNF part? Yeah, maybe, but it is another story.
I decided to drop it this time.
You can refine it but please use better format instead of such incomplete one.

> By the way:
> I wonder about the shown version identifier.
> Will the patch numbering need also further considerations?

No.

> >> …
> >>> +++ b/Documentation/admin-guide/bootconfig.rst
> >> …
> >>> +If you think that kernel/init options become too long to write in boot-loader
> >>> +configuration file or you want to comment on each option, the boot
> >>> +configuration may be suitable. …
> >>
> >> Would you like to specify any settings in the boot configuration file
> >> because the provided storage capacity would be too limited by the kernel command line?
> >
> > Yes.
> 
> How will affected places be improved after such an agreement?

Would you please make a patch of new sentence?

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [v5.1] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>> I got the impression that we are in the process of constructing another patch together
>> which will fix known wording weaknesses.
>
> Would you mean the broken EBNF part?

I hope that such software design approaches can also be reconsidered.


> Yeah, maybe, but it is another story.

Other concrete update suggestions are probably easier to integrate before.
Which change opportunities will be picked up next?

Regards,
Markus

Re: [v5.1] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

>>>> …
>>>>> +++ b/Documentation/admin-guide/bootconfig.rst
>>>> …
>>>>> +If you think that kernel/init options become too long to write in boot-loader
>>>>> +configuration file or you want to comment on each option, the boot
>>>>> +configuration may be suitable. …
>>>>
>>>> Would you like to specify any settings in the boot configuration file
>>>> because the provided storage capacity would be too limited by the kernel command line?
>>>
>>> Yes.
>>
>> How will affected places be improved after such an agreement?
>
> Would you please make a patch of new sentence?

Not directly.

* If I would need to provide another wording alternative as a concrete patch,
  I would have to wait until previously accepted changes would become available
  in a Linux development repository.

* So I would find it easier to agree on wording variants during our current
  development discussion from which you would present results as a subsequent patch.

Regards,
Markus

Re: [PATCH v5.1] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

…
> Changes in v5.1:
>  - Fix some mistakes (Thanks Randy!)
…
> Changes in v2:
>  - Fixes additional typos (Thanks Markus and Randy!)
…

Can such information trigger the addition of the tag “Reported-by”?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=fffb08b37df928475fef9c7f2aafddc2f6ebfaf4#n584

Regards,
Markus

Re: [PATCH v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

…
> +++ b/Documentation/admin-guide/bootconfig.rst
…
> +If you think that kernel/init options becomes too long to write in boot-loader
> +configuration file or you want to comment on each option, the boot
> +configuration may be suitable. …

Will remaining open issues get any attention for such software?

Will further collateral evolution happen around presented information?

Regards,
Markus

Re: [PATCH v5] Documentation: bootconfig: Update boot configuration documentation

[Markus Elfring]

…
> +++ b/Documentation/admin-guide/bootconfig.rst
…
>  … word must contain only alphabets, numbers, …

Would the wording “… alphanumeric characters …” be nicer?

Regards,
Markus

Re: [PATCH v5] Documentation: bootconfig: Update boot configuration documentation

[Randy Dunlap]

On 3/5/20 2:19 AM, Markus Elfring wrote:
> …
>> +++ b/Documentation/admin-guide/bootconfig.rst
> …
>>  … word must contain only alphabets, numbers, …
> 
> Would the wording “… alphanumeric characters …” be nicer?

Sure.

-- 
~Randy

Re: [v5 0/1] Documentation: bootconfig: Documentation updates

[Markus Elfring]

> - Fix some typos.

These changes were incomplete.

Regards,
Markus