[PATCH v3] dts: Change hugepage runtime config to 2MB Exclusively

[Juraj Linkeš]

Don't forget to run the ../devtools/dts-check-format.sh script, it
found one issue:
framework/testbed_model/os_session.py:351: [D] D417 Missing argument
descriptions in the docstring [pydocstyle]

On Tue, Apr 16, 2024 at 8:18 PM Nicholas Pratte <npratte at iol.unh.edu> wrote:
>
> The previous implementation configures and allocates hugepage sizes
> based on a system default. This can lead to two problems: overallocation of
> hugepages (which may crash the remote host), and configuration of hugepage
> sizes that are not recommended during runtime. This new implementation
> allows only 2MB hugepage allocation during runtime; any other unique
> hugepage size must be configured by the end-user for initializing DTS.
>
> If the amount of 2MB hugepages requested exceeds the amount of 2MB
> hugepages already configured on the system, then the system will remount
> hugepages to cover the difference. If the amount of hugepages requested is
> either less than or equal to the amount already configured on the system,
> then nothing is done.
>
> Bugzilla ID: 1370
> Signed-off-by: Nicholas Pratte <npratte at iol.unh.edu>
> Reviewed-by: Jeremy Spewock <jspewock at iol.unh.edu>
> ---
>  doc/guides/tools/dts.rst                     |  7 +++++-
>  dts/conf.yaml                                |  4 ++--
>  dts/framework/config/__init__.py             |  4 ++--
>  dts/framework/config/conf_yaml_schema.json   |  6 ++---
>  dts/framework/config/types.py                |  2 +-
>  dts/framework/testbed_model/linux_session.py | 24 +++++++++++---------
>  dts/framework/testbed_model/node.py          |  8 ++++++-
>  dts/framework/testbed_model/os_session.py    |  4 +++-
>  8 files changed, 37 insertions(+), 22 deletions(-)
>
> diff --git a/doc/guides/tools/dts.rst b/doc/guides/tools/dts.rst
> index 47b218b2c6..1103db0faa 100644
> --- a/doc/guides/tools/dts.rst
> +++ b/doc/guides/tools/dts.rst
> @@ -131,7 +131,12 @@ There are two areas that need to be set up on a System Under Test:
>
>       You may specify the optional hugepage configuration in the DTS config file.
>       If you do, DTS will take care of configuring hugepages,
> -     overwriting your current SUT hugepage configuration.
> +     overwriting your current SUT hugepage configuration. Configuration of hugepages via DTS
> +     allows only for configuration of 2MB hugepages.

I'd like to see a quick explanation of why we only do 2MB hugepages,
like you mentioned in the commit message.

> Thus, if your needs require hugepage
> +     sizes not equal to 2MB, then you these configurations must be done outside of the DTS

typo - you is extra. And I think this should be configuration singular
- this configuration must be done.

> +     framework; moreover, if you do not desire the use of 2MB hugepages, and instead perfer

prefer

> +     other sizes (e.g 1GB), then we assume that hugepages have been manually configued before

configured

> +     runtime.

Looks like the two sentences (separated by semicolon) are saying the same thing.

>
>     * System under test configuration
>