[PATCH v4 16/20] arch_topology: Drop unnecessary check for uninitialised package_id
Sudeep Holla
sudeep.holla at arm.com
Mon Jun 27 09:30:08 PDT 2022
On Mon, Jun 27, 2022 at 02:12:52PM +0100, Ionela Voinescu wrote:
> On Tuesday 21 Jun 2022 at 20:20:30 (+0100), Sudeep Holla wrote:
> > With the support of socket node parsing from the device tree and
> > assigning 0 as package_id in absence of socket nodes, there is no need
> > to check for invalid package_id. It is always initialised to 0 or values
> > from the device tree socket nodes.
> >
> > Just drop that now redundant check for uninitialised package_id.
> >
> > Signed-off-by: Sudeep Holla <sudeep.holla at arm.com>
> > ---
> > drivers/base/arch_topology.c | 11 -----------
> > 1 file changed, 11 deletions(-)
> >
> > diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> > index 46fa1b70b02b..42448a5a9412 100644
> > --- a/drivers/base/arch_topology.c
> > +++ b/drivers/base/arch_topology.c
> > @@ -611,7 +611,6 @@ static int __init parse_dt_topology(void)
> > {
> > struct device_node *cn, *map;
> > int ret = 0;
> > - int cpu;
> >
> > cn = of_find_node_by_path("/cpus");
> > if (!cn) {
> > @@ -633,16 +632,6 @@ static int __init parse_dt_topology(void)
> >
> > topology_normalize_cpu_scale();
> >
> > - /*
> > - * Check that all cores are in the topology; the SMP code will
> > - * only mark cores described in the DT as possible.
> > - */
> > - for_each_possible_cpu(cpu)
> > - if (cpu_topology[cpu].package_id < 0) {
> > - ret = -EINVAL;
> > - break;
> > - }
> > -
>
> Maybe it would still be good to keep this for systems with potential
> errors in DT, where one forgets to add a core in cpu-map.
>
Though I would ideally prefer to catch such DT issues with schema, I know
we are no there yet. So I agree to retain this.
> For example, if I modify juno.dts as follows:
>
> --- a/arch/arm64/boot/dts/arm/juno.dts
> +++ b/arch/arm64/boot/dts/arm/juno.dts
> @@ -51,12 +51,9 @@ core0 {
> cpu = <&A53_0>;
> };
> core1 {
> - cpu = <&A53_1>;
> - };
> - core2 {
> cpu = <&A53_2>;
> };
> - core3 {
> + core2 {
> cpu = <&A53_3>;
> };
> };
>
> and miss a little core in cluster1, I would end up with an incomplete
> topology: core3 would have cluster_id as -1, while all other CPUs would
> have a valid value; also, core3 would have package_id = -1.
>
Indeed. I didn't consider the case where DT would have issues when I dropped
this check. I will drop this patch. Thanks again.
--
Regards,
Sudeep
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