The available hugepage is 1G less than the value set up when the vswitch_type parameter is set to: 'none'

[Matheus Machado Guilhermino]

Brief Description
-----------------

Increased the huge page memory up to 32 Gib by running the below command:

$ system host-memory-modify controller-0 0 -1G 32
[sysadmin@controller-0 ~(keystone_admin)]$ system host-memory-list controller-0+-----------+---------+------------+---------+----------------+--------+---------+-------------+------------+--------------+----------------------+-----------------+-----------------+-------------------+-----------------+-----------------+-------------------+---------------+| processor | mem_tot | mem_platfo | mem_ava | hugepages(hp)_ | vs_hp_ | vs_hp_t | vs_hp_avail | vs_hp_reqd | app_total_4K | app_hp_as_percentage | app_hp_total_2M | app_hp_avail_2M | app_hp_pending_2M | app_hp_total_1G | app_hp_avail_1G | app_hp_pending_1G | app_hp_use_1G || | al(MiB) | rm(MiB) | il(MiB) | configured | size(M | otal | | | | | | | | | | | || | | | | | iB) | | | | | | | | | | | | |+-----------+---------+------------+---------+----------------+--------+---------+-------------+------------+--------------+----------------------+-----------------+-----------------+-------------------+-----------------+-----------------+-------------------+---------------+| 0 | 116205 | 10000 | 115181 | True | 1024 | 0 | 0 | None | 21359872 | False | 0 | 0 | None | 32 | 31 | None | True |+-----------+---------+------------+---------+----------------+--------+---------+-------------+------------+--------------+----------------------+-----------------+-----------------+-------------------+-----------------+-----------------+-------------------+---------------+
Examining the current memory allocation, the following parameter change was observed:

app_hp_total_1G = 32 Gib
app_hp_avail_1G = 31 Gib

the following formula is used to calculate memory:

app_hp_total_1G = app_hp_avail_1G + vSwitch Page

According to the documentation, the vSwitch Huge Pages are not allocated if the vswitch_type is set to None

When checking with "system show", the vSwitch type is set to none:

[sysadmin@controller-0 ~(keystone_admin)]$ system show | grep vswitch_type
| vswitch_type | none |

Severity
--------

Minor

Steps to Reproduce
------------------

Execute "system host-memory-modify controller-0 0 -1G 32"
check available app_hp_avail_1G with "system host-memory-list controller-0"

Expected Behavior
------------------

app_hp_avail_1G equal to app_hp_total_1G on "system host-memory-list controller-0"

Actual Behavior
----------------

app_hp_avail_1G less than app_hp_total_1G on "system host-memory-list controller-0"

Reproducibility
---------------

100%

System Configuration
--------------------

Simplex lab environment

Last Pass
---------

N/A

Timestamp/Logs
--------------

No alarms observed

Test Activity
-------------

Developer Testing

Workaround
-------------

N/A

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/stx-puppet/+/882092

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/config-files/+/882181

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/stx-puppet/+/882092
Committed: https://opendev.org/starlingx/stx-puppet/commit/248c258bc988da7f015616dde44b302d13890ea7
Submitter: "Zuul (22348)"
Branch: master

commit 248c258bc988da7f015616dde44b302d13890ea7
Author: Matheus Guilhermino <email address hidden>
Date: Tue May 2 12:10:51 2023 -0300

    Disable postgres huge page usage

    In order to use the total available 1G hugepages space when
    vswitch_type parameter is set to 'none', the value huge_pages=off
    needs to be included on /etc/postgresql/postgresql.conf since, by
    default, postgres uses hugepages if available.

    The postgresql.pp is a manifest called on unlock

    Test Plan
    PASS: AIO-SX: Successfully bootstrapped and unlocked
    PASS: Verified that app_hp_avail_1G == app_hp_total_1G after
          increasing huge page memory to the amount indicated by
          app_hp_total_1G (total and available values match when
          no applications are using huge pages).
    PASS: Output of 'cat /proc/meminfo' matches output of
          'system host-memory-list controller-0'
          (HugePages_Free == app_hp_avail_1G).

    Closes-bug: 2018324

    Change-Id: Iab7b7518fdcfccd2761778ed6a875a42cd35c34c
    Signed-off-by: Matheus Guilhermino <email address hidden>