[PATCH v3 09/14] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1

[Quentin Perret]

On Friday 13 Nov 2020 at 09:37:14 (+0000), Will Deacon wrote:
> If the scheduler cannot find an allowed CPU for a task,
> cpuset_cpus_allowed_fallback() will widen the affinity to cpu_possible_mask
> if cgroup v1 is in use.
> 
> In preparation for allowing architectures to provide their own fallback
> mask, just return early if we're not using cgroup v2 and allow
> select_fallback_rq() to figure out the mask by itself.
> 
> Cc: Li Zefan <lizefan at huawei.com>
> Cc: Tejun Heo <tj at kernel.org>
> Cc: Johannes Weiner <hannes at cmpxchg.org>
> Signed-off-by: Will Deacon <will at kernel.org>

That makes select_fallback_rq() slightly more expensive if you're using
cgroup v1, but I don't expect that be really measurable in real-world
workloads, so:

Reviewed-by: Quentin Perret <qperret at google.com>

Thanks,
Quentin