Re: [Xen-devel] [PATCH v2 09/48] xen/sched: move some per-vcpu items to struct sched_unit

[Juergen Gross <jgross@xxxxxxxx>]

On 09.09.19 08:55, Jan Beulich wrote:
> On 09.09.2019 08:39, Juergen Gross wrote:
> > On 04.09.19 16:16, Jan Beulich wrote:
> > > On 09.08.2019 16:57, Juergen Gross wrote:
> > > > V2:
> > > > - move affinity_broken back to struct vcpu (Jan Beulich)
> > > But this alone won't work: Now a 2nd vCPU in a unit will clobber
> > > what a 1st one may have set as an affinity override. I don't
> > > think you can get away without a per-vCPU CPU mask, or a
> > > combination of per-vCPU and per-unit state flags.
> > See patch 24: this one adds a helper sched_check_affinity_broken() for
> > that purpose iterating over the vcpus checking the affinity_broken flags
> > and returning true if any of the vcpus has its flag set.
> Okay, patch 24 is still before multiple vCPU-s per unit become
> possible, so no intermediate breakage. But could you please
> make this explicit by slightly extending the description of the
> change here?
Yes. Will extend the commit message with:

  When support of multiple vcpus per sched_unit is being added, a unit
  is regarded as being subject to "broken affinity" when any of its
  vcpus has the affinity_broken flag set.


Juergen

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