RE: [PATCH v2] dts: Change hugepage runtime config to 2MB Exclusively

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Nicholas Pratte [mailto:npratte@iol.unh.edu]
> Sent: Tuesday, 9 April 2024 19.28
> 
> 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@iol.unh.edu>
> Reviewed-by: Jeremy Spewock <jspewock@iol.unh.edu>
> ---
>  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 | 15 ++++++---------
>  5 files changed, 14 insertions(+), 17 deletions(-)
> 
> diff --git a/dts/conf.yaml b/dts/conf.yaml
> index 8068345dd5..56c3ae6f4c 100644
> --- a/dts/conf.yaml
> +++ b/dts/conf.yaml
> @@ -35,7 +35,7 @@ nodes:
>      lcores: "" # use all the available logical cores
>      use_first_core: false # tells DPDK to use any physical core
>      memory_channels: 4 # tells DPDK to use 4 memory channels
> -    hugepages:  # optional; if removed, will use system hugepage
> configuration
> +    hugepages_2mb: # optional; if removed, will use system hugepage
> configuration
>          amount: 256
>          force_first_numa: false
>      ports:
> @@ -71,7 +71,7 @@ nodes:
>          os_driver: rdma
>          peer_node: "SUT 1"
>          peer_pci: "0000:00:08.1"
> -    hugepages:  # optional; if removed, will use system hugepage
> configuration
> +    hugepages_2mb: # optional; if removed, will use system hugepage
> configuration
>          amount: 256
>          force_first_numa: false
>      traffic_generator:
> diff --git a/dts/framework/config/__init__.py
> b/dts/framework/config/__init__.py
> index 4cb5c74059..b6f820e39e 100644
> --- a/dts/framework/config/__init__.py
> +++ b/dts/framework/config/__init__.py
> @@ -255,8 +255,8 @@ def from_dict(
>              Either an SUT or TG configuration instance.
>          """
>          hugepage_config = None
> -        if "hugepages" in d:
> -            hugepage_config_dict = d["hugepages"]
> +        if "hugepages_2mb" in d:
> +            hugepage_config_dict = d["hugepages_2mb"]
>              if "force_first_numa" not in hugepage_config_dict:
>                  hugepage_config_dict["force_first_numa"] = False
>              hugepage_config = HugepageConfiguration(**hugepage_config_dict)
> diff --git a/dts/framework/config/conf_yaml_schema.json
> b/dts/framework/config/conf_yaml_schema.json
> index 4731f4511d..f4d7199523 100644
> --- a/dts/framework/config/conf_yaml_schema.json
> +++ b/dts/framework/config/conf_yaml_schema.json
> @@ -146,7 +146,7 @@
>          "compiler"
>        ]
>      },
> -    "hugepages": {
> +    "hugepages_2mb": {
>        "type": "object",
>        "description": "Optional hugepage configuration. If not specified,
> hugepages won't be configured and DTS will use system configuration.",
>        "properties": {
> @@ -253,8 +253,8 @@
>              "type": "integer",
>              "description": "How many memory channels to use. Optional,
> defaults to 1."
>            },
> -          "hugepages": {
> -            "$ref": "#/definitions/hugepages"
> +          "hugepages_2mb": {
> +            "$ref": "#/definitions/hugepages_2mb"
>            },
>            "ports": {
>              "type": "array",
> diff --git a/dts/framework/config/types.py b/dts/framework/config/types.py
> index 1927910d88..016e0c3dbd 100644
> --- a/dts/framework/config/types.py
> +++ b/dts/framework/config/types.py
> @@ -46,7 +46,7 @@ class NodeConfigDict(TypedDict):
>      """Allowed keys and values."""
> 
>      #:
> -    hugepages: HugepageConfigurationDict
> +    hugepages_2mb: HugepageConfigurationDict
>      #:
>      name: str
>      #:
> diff --git a/dts/framework/testbed_model/linux_session.py
> b/dts/framework/testbed_model/linux_session.py
> index 5d24030c3d..37f5eacb21 100644
> --- a/dts/framework/testbed_model/linux_session.py
> +++ b/dts/framework/testbed_model/linux_session.py
> @@ -15,7 +15,7 @@
> 
>  from typing_extensions import NotRequired
> 
> -from framework.exception import RemoteCommandExecutionError
> +from framework.exception import ConfigurationError,
> RemoteCommandExecutionError
>  from framework.utils import expand_range
> 
>  from .cpu import LogicalCore
> @@ -87,25 +87,22 @@ def get_dpdk_file_prefix(self, dpdk_prefix: str) -> str:
>      def setup_hugepages(self, hugepage_count: int, force_first_numa: bool) ->
> None:

You should either rename this to setup_hugepages_2mb() or preferably add a hugepage_size parameter.

>          """Overrides :meth:`~.os_session.OSSession.setup_hugepages`."""
>          self._logger.info("Getting Hugepage information.")
> -        hugepage_size = self._get_hugepage_size()
> +        if "hugepages-2048kB" not in self.send_command("ls
> /sys/kernel/mm/hugepages").stdout:
> +            raise ConfigurationError("2MB hugepages not supported by
> operating system")
>          hugepages_total = self._get_hugepages_total()
>          self._numa_nodes = self._get_numa_nodes()
> 
> -        if force_first_numa or hugepages_total != hugepage_count:
> +        if force_first_numa or hugepages_total < hugepage_count:
>              # when forcing numa, we need to clear existing hugepages
> regardless
>              # of size, so they can be moved to the first numa node
> -            self._configure_huge_pages(hugepage_count, hugepage_size,
> force_first_numa)
> +            self._configure_huge_pages(hugepage_count, 2048,
> force_first_numa)
>          else:
>              self._logger.info("Hugepages already configured.")
>          self._mount_huge_pages()
> 
> -    def _get_hugepage_size(self) -> int:
> -        hugepage_size = self.send_command("awk '/Hugepagesize/ {print $2}'
> /proc/meminfo").stdout
> -        return int(hugepage_size)
> -

Removing _get_hugepage_size() is OK; alternatively rename it to _get_hugepage_default_size().

>      def _get_hugepages_total(self) -> int:

Also here, preferably add a size parameter, or rename it to _get_hugepages_2mb_total().

>          hugepages_total = self.send_command(
> -            "awk '/HugePages_Total/ { print $2 }' /proc/meminfo"
> +            "cat /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages"
>          ).stdout
>          return int(hugepages_total)
> 
> --
> 2.44.0

With suggested changes,
Acked-by: Morten Brørup <mb@smartsharesystems.com>