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

[Nicholas Pratte <npratte@iol.unh.edu>]

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                                |  8 ++++----
 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 | 21 +++++++++-----------
 5 files changed, 19 insertions(+), 22 deletions(-)

diff --git a/dts/conf.yaml b/dts/conf.yaml
index 8068345dd5..3690e77ee5 100644
--- a/dts/conf.yaml
+++ b/dts/conf.yaml
@@ -35,8 +35,8 @@ 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
-        amount: 256
+    hugepages_2mb: # optional; if removed, will use system hugepage configuration
+        amount: 2560
         force_first_numa: false
     ports:
       # sets up the physical link between "SUT 1"@000:00:08.0 and "TG 1"@0000:00:08.0
@@ -71,8 +71,8 @@ nodes:
         os_driver: rdma
         peer_node: "SUT 1"
         peer_pci: "0000:00:08.1"
-    hugepages:  # optional; if removed, will use system hugepage configuration
-        amount: 256
+    hugepages_2mb: # optional; if removed, will use system hugepage configuration
+        amount: 2560
         force_first_numa: false
     traffic_generator:
         type: SCAPY
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..ad3c811301 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:
         """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, 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)
-
     def _get_hugepages_total(self) -> int:
         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)
 
@@ -136,15 +133,15 @@ def _supports_numa(self) -> bool:
         # there's no reason to do any numa specific configuration)
         return len(self._numa_nodes) > 1
 
-    def _configure_huge_pages(self, amount: int, size: int, force_first_numa: bool) -> None:
+    def _configure_huge_pages(self, amount: int, force_first_numa: bool) -> None:
         self._logger.info("Configuring Hugepages.")
-        hugepage_config_path = f"/sys/kernel/mm/hugepages/hugepages-{size}kB/nr_hugepages"
+        hugepage_config_path = "/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages"
         if force_first_numa and self._supports_numa():
             # clear non-numa hugepages
             self.send_command(f"echo 0 | tee {hugepage_config_path}", privileged=True)
             hugepage_config_path = (
                 f"/sys/devices/system/node/node{self._numa_nodes[0]}/hugepages"
-                f"/hugepages-{size}kB/nr_hugepages"
+                f"/hugepages-2048kB/nr_hugepages"
             )
 
         self.send_command(f"echo {amount} | tee {hugepage_config_path}", privileged=True)
-- 
2.44.0