This is a minimal viable implementation of a post-loaded profile
feature. It was implemented to satisfy the needs of the
kernel_settings Ansible role.
https://github.com/linux-system-roles/kernel_settings
This feature allows us to apply a profile in a way that is
somewhat separate from the way profiles from the active_profile file
are applied. Namely, the post-loaded profile is always applied after
all the profiles from the active_profile (or more precisely, the
post-loaded profile is always put to the tail of the profile chain
when merging). Also, the post-loaded profile setting is not affected
by running 'tuned-adm profile <some profile>' - the post-loaded
profile remains applied.
The name of the post-loaded profile is stored in
/etc/tuned/post_loaded_profile.
The lack of support for multiple post-loaded profiles was more or less
an arbitrary decision. There are no problems with it, as far as I can
see. However, there is currently no use case for multiple post-loaded
profiles, so I decided to make things easier for our future selves -
it's one less thing to worry about if we need to make changes to the
profile loading logic. We can add support for multiple post-loaded
profiles anytime.
A number of other design decisions went into the
implementation. They are listed here:
https://github.com/redhat-performance/tuned/pull/272
Resolves: rhbz#1798183
Signed-off-by: Ondřej Lysoněk <olysonek@redhat.com>
