Re: [PATCH v6 0/2] Methodology change for hugepage configuration

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

What's the difference between this version and v4?

On Tue, May 7, 2024 at 7:44 PM Nicholas Pratte <npratte@iol.unh.edu> wrote:
>
> In order to prevent accidental misconfiguration of hugepages at runtime,
> the following changes are made to only allow for configuration of 2MB
> hugepages within the DTS config.yaml. In the previous implementation, a
> default hugepage size was selected via the size listed in /proc/meminfo.
> The problem with this implementation is that, assuming the end-user has
> made prior modifications to the system, /proc/meminfo may default to
> hugepage sizes that are not recommended to be configured at runtime
> (i.e. 1GB hugepages). This can lead to two problems: overallocation of
> hugepages (which may crash the remote host) configuration of hugepages
> sizes that are not recommended during runtime. In this new implementation,
> we stipulate that any runtime hugepage configuration size that is not 2MB
> is considered an outlier. If the end-user would like to configure either
> 1GB hugepages or any unique hugepage size outside of 2MB, then they should
> make these configurations either at startup (in the case of 1GB hugepages)
> or runtime outside of DTS configuration (if a user would like hugepages
> that are not 2MB). In either case, the expectation is that, if wish to
> use hugepage sizes that are not 2MB, you will make these changes outside
> and prior to the initialization of DTS.
>
> The end-user has two options: remove the option for hugepage
> configuration in the conf.yaml, or keep the option and specify the
> amount of 2MB hugepages desired. In the case of the former, then we assume
> that hugepages are already configured prior to DTS initialization. In
> the latter case, the user must define the amount of 2MB hugepages to be
> configured at runtime. 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 greater than or equal to the amount
> already configured on the system, then nothing is done.
>
> Nicholas Pratte (2):
>   dts: Change hugepage runtime config to 2MB Exclusively
>   dts: Change hugepage 'amount' to a different term
>
>  doc/guides/tools/dts.rst                     |  6 ++++-
>  dts/conf.yaml                                |  8 +++---
>  dts/framework/config/__init__.py             |  8 +++---
>  dts/framework/config/conf_yaml_schema.json   | 12 ++++-----
>  dts/framework/config/types.py                |  4 +--
>  dts/framework/testbed_model/linux_session.py | 28 +++++++++++---------
>  dts/framework/testbed_model/node.py          |  4 ++-
>  dts/framework/testbed_model/os_session.py    |  7 ++++-
>  8 files changed, 45 insertions(+), 32 deletions(-)
>
> --
> 2.44.0
>