Re: [RFC PATCH 1/3] sched/fair: Embed sched_entity into cfs_rq

[Zecheng Li]

Hi Peter,

On Thu, Jun 5, 2025 at 10:28 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> This also blows up struct rq for no reason.

I'm working on a v2 change that could avoid this overhead by allocating
struct cfs_rq and struct sched_entity together as a combined struct
(e.g., struct {struct cfs_rq cfs_rq; struct sched_entity se;}) on
non-root task groups. This would allow us to save the extra sched_entity
inside struct rq.

> I would much rather you all investigate if you can make the flattened
> cgroup stuff from Rik work.

The flattened cgroup work seems to be a separate, larger architectural
change. This patch series focuses on micro-architecture optimizations
to existing memory layouts without changing functionality.

Regards,
Zecheng