ACK: [SRU][N][PATCH 0/1] Fix cpuset behavior to v1 following the changes from upstream stable patches.

[Edoardo Canepa]

Acked-by: Edoardo Canepa <edoardo.canepa at canonical.com>

On 12/18/25 09:51, Mehmet Basaran wrote:
> BugLink: https://bugs.launchpad.net/bugs/2128722
>
> SRU Justification:
>
> [Impact]
>
> For noble , some of the applied upstream commits are using "CONFIG_CPUSETS_V1"
> to enable/disable some code paths. This changes the behaviour of cpusets and
> currently noble is neither V1 nor V2. Because of this, "cpuset_inherit" and
> "cpuset_hotplug" test cases are failing in ubuntu_ltp_controllers test suite.
> For noble, since this is an LTS release we should continue behave like V1.
>
> [Fix]
>
> Added "CONFIG_CPUSETS_V1" kernel config option. This was added to upstream
> via the following commit:
>
>      commit 1abab1ba0775036bb67c6c57945c637be644c04f
>      cgroup/cpuset: guard cpuset-v1 code under CONFIG_CPUSETS_V1
>
> I have chosen to go with a SAUCE patch since, the commit above depends on
> other commits. And in the future, we can revert this one and apply the
> dependent commits if we want to follow cpusets follow from 6.12 versions so
> that there are less conflicts between upstream stable and noble sources.
>
> The other solution is to remove the use of "CONFIG_CPUSETS_V1" macro from
> sources. However this will also cause noble and upstream stable sources to
> diverge and make it difficult to backport patches.
>
> [Test Plan]
>
> Rerun cpuset_* tests in ubuntu_ltp_controllers test suite. All passed.
>
> [Where problems could occur]
>
> cpusets can behave like neither v1 nor v2 which can lead to incorrect
> allocation of scheduling domains for cgroups.
>
> As long as cpuset code paths are separated correctly for v1 and v2 in the
> upstream stable branches, backported commits should work as well. So,
> essentially, this is a safe fix.
>
> Mehmet Basaran (1):
>    UBUNTU: SAUCE: Enable upstream config option "CONFIG_CPUSETS_V1"
>
>   debian.master/config/annotations |  1 +
>   init/Kconfig                     | 13 +++++++++++++
>   2 files changed, 14 insertions(+)
>
> --
> 2.43.0
>
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