Hi Maddy, Hemant, Anju,
On Thu, Mar 16, 2017 at 01:05:02PM +0530, Madhavan Srinivasan wrote:
[..snip..]
> +
> +static void core_imc_change_cpu_context(int old_cpu, int new_cpu)
> +{
> + if (!core_imc_pmu)
> + return;
> + perf_pmu_migrate_context(&core_imc_pmu->pmu, old_cpu, new_cpu);
> +}
> +
> +
> +static int ppc_core_imc_cpu_online(unsigned int cpu)
> +{
> + int ret;
> +
> + /* If a cpu for this core is already set, then, don't do anything */
> + ret = cpumask_any_and(&core_imc_cpumask,
> + cpu_sibling_mask(cpu));
> + if (ret < nr_cpu_ids)
> + return 0;
> +
> + /* Else, set the cpu in the mask, and change the context */
> + cpumask_set_cpu(cpu, &core_imc_cpumask);
> + core_imc_change_cpu_context(-1, cpu);
So, in the core case, we are ok as long as any cpu in the core is
present in the imc_cpumask. It need not have to be the smallest online
cpu in the core.
Can the same logic be applied to the earlier nest case ?
We can have a single function for cpu_offline and cpu_online which
implements these checks and sets the cpu bit if required.
ppc_entity_imc_cpu_offline(unsigned int cpu, cpumask_t
entity_imc_mask,
entity_imc_change_cpu_context_fn)
{
.
.
.
}
static ppc_nest_imc_cpu_offline(unsigned int cpu)
{
return ppc_entity_imc_cpu_offline(cpu, nest_imc_mask,
nest_imc_change_cpu_context);
}
And similar ones for core imc and thread imc.
Does this sound reasonable ?
> + return 0;
> +}
> +
> +static int ppc_core_imc_cpu_offline(unsigned int cpu)
> +{
> + int target;
> + unsigned int ncpu;
> +
> + /*
> + * clear this cpu out of the mask, if not present in the mask,
> + * don't bother doing anything.
> + */
> + if (!cpumask_test_and_clear_cpu(cpu, &core_imc_cpumask))
> + return 0;
> +
> + /* Find any online cpu in that core except the current "cpu" */
> + ncpu = cpumask_any_but(cpu_sibling_mask(cpu), cpu);
> +
> + if (ncpu < nr_cpu_ids) {
> + target = ncpu;
> + cpumask_set_cpu(target, &core_imc_cpumask);
> + } else
> + target = -1;
> +
> + /* migrate the context */
> + core_imc_change_cpu_context(cpu, target);
> +
> + return 0;
> +}
> +
--
Thanks and Regards
gautham.
