Re: [RFCv5 PATCH 16/46] sched: Allocate and initialize energy data structures

Peter Zijlstra
2015-08-12T17:23:30Z

On Wed, Aug 12, 2015 at 06:09:59PM +0100, Dietmar Eggemann wrote:
> > One more question, if fn() returns a full structure, why are we
> > allocating and copying the thing? Its all const read only data, right?
> >
>
> Yeah, that's not strictly necessary. I could get rid of all the
> allocation/copying/ and freeing code and just simply set sd->groups->sge
> = fn(cpu) in init_sched_energy(). Plus delete the atomic_t ref in struct
> sched_group_energy.
>
> In this case, should I still keep the check_sched_energy_data() function
> to verify that the scheduler got valid data via the struct
> sched_domain_topology_level table from the arch, i.e. to make sure that
> the per-cpu provided sd energy data is consistent for all cpus within
> the sched group cpumask?

Oh yes very much. We want sanity checking of the data handed.