Re: [PATCH 0/5] xen/sched: rtds: add per-cpupool admission control

[Furkan Çalışkan <frn1furkan10@xxxxxxxxx>]

On 8/26/26 07:57, Furkan Caliskan wrote:
> RTDS currently has no admission control: nothing stops the sum of
> all admitted units' (budget/period) reservations in a cpupool from
> exceeding what its pCPUs can actually provide. Once that happens,
> the global-EDF deadline guarantees the scheduler is built around no
> longer hold for any unit sharing that pool.
> 
> This series adds admission control to prevent that, tracks and
> report utilization, and makes the check toggleable per cpupool so
> an operator can disable it if they intentionally want to overcommit.
> 
> Patch 1 introduces the core mechanism: a running utilization total
> per cpupool, a fixed-point representation of a unit's (budget/period),
> and a capacity check enforced in rt_alloc_udata()/rt_free_udata() -
> the lifecycle hooks that catch every new unit's default reservation.
> 
> Patch 2 extends the same check to domctl, so growing an existing
> reservation via xl sched-rtds is checked too.
> 
> Patch 3 reports a cpupool's admitted utilization agains its capacity
> via the 'r' debug key.
> 
> Patch 4 makes admission control itself toggleable per cpupool
> (enabled by default) via sysctl.
> 
> Patch 5 wires that toggle through libxl and adds -s/-a to
> xl sched-rtds, and documents it.
> 
> Furkan Caliskan (5):
>   xen/sched: rtds: add global-EDF utilization admission control
>   xen/sched: rtds: enforce admission control in xl sched-rtds
>   xen/sched: rtds: report utilization and cap via debug key
>   xen/sched: rtds: make admission control cpupool-wide toggleable
>   tools: expose admission control toggle via xl sched-rtds
> 
>  docs/man/xl.1.pod.in                 |  20 +++
>  tools/golang/xenlight/helpers.gen.go |  23 +++
>  tools/golang/xenlight/types.gen.go   |   4 +
>  tools/include/libxl.h                |   4 +
>  tools/include/xenctrl.h              |   6 +
>  tools/libs/ctrl/xc_rt.c              |  40 ++++++
>  tools/libs/light/libxl_sched.c       |  46 ++++++
>  tools/libs/light/libxl_types.idl     |   5 +
>  tools/xl/xl_cmdtable.c               |   8 +-
>  tools/xl/xl_sched.c                  | 103 +++++++++++++-
>  xen/common/sched/rt.c                | 205 ++++++++++++++++++++++++++-
>  xen/include/public/sysctl.h          |   5 +
>  12 files changed, 463 insertions(+), 6 deletions(-)
> 

Hi Juergen,

Can I get a review on this series please?
Thanks,

Furkan