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powerpc/smp: Use cpu_to_chip_id() to find core siblings

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When building the CPU scheduler topology the kernel uses the ibm,chipid
property from the devicetree to group logical CPUs. Currently the DT
search for this property is open-coded in smp.c and this functionality
is a duplication of what's in cpu_to_chip_id() already. This patch
removes the existing search in favor of that.

It's worth mentioning that the semantics of the search are different
in cpu_to_chip_id(). When there is no ibm,chipid in the CPUs node it
will also search /cpus and / for the property, but this should not
effect the output topology.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Oliver O'Halloran 2017-06-29 17:12:53 +10:00 committed by Michael Ellerman
parent 197267d035
commit e3d8b67e2c
1 changed files with 11 additions and 26 deletions
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37
arch/powerpc/kernel/smp.c
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@ -830,19 +830,11 @@ EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
static void traverse_siblings_chip_id(int cpu, bool add, int chipid)
{
const struct cpumask *mask;
struct device_node *np;
int i, plen;
const __be32 *prop;
const struct cpumask *mask = add ? cpu_online_mask : cpu_present_mask;
int i;
mask = add ? cpu_online_mask : cpu_present_mask;
for_each_cpu(i, mask) {
np = of_get_cpu_node(i, NULL);
if (!np)
continue;
prop = of_get_property(np, "ibm,chip-id", &plen);
if (prop && plen == sizeof(int) &&
of_read_number(prop, 1) == chipid) {
if (cpu_to_chip_id(i) == chipid) {
if (add) {
cpumask_set_cpu(cpu, cpu_core_mask(i));
cpumask_set_cpu(i, cpu_core_mask(cpu));
@ -851,7 +843,6 @@ static void traverse_siblings_chip_id(int cpu, bool add, int chipid)
cpumask_clear_cpu(i, cpu_core_mask(cpu));
}
}
of_node_put(np);
}
}
@ -881,21 +872,15 @@ static void traverse_core_siblings(int cpu, bool add)
{
struct device_node *l2_cache, *np;
const struct cpumask *mask;
int i, chip, plen;
const __be32 *prop;
int chip_id;
int i;
/* First see if we have ibm,chip-id properties in cpu nodes */
np = of_get_cpu_node(cpu, NULL);
if (np) {
chip = -1;
prop = of_get_property(np, "ibm,chip-id", &plen);
if (prop && plen == sizeof(int))
chip = of_read_number(prop, 1);
of_node_put(np);
if (chip >= 0) {
traverse_siblings_chip_id(cpu, add, chip);
return;
}
/* threads that share a chip-id are considered siblings */
chip_id = cpu_to_chip_id(cpu);
if (chip_id >= 0) {
traverse_siblings_chip_id(cpu, add, chip_id);
return;
}
l2_cache = cpu_to_l2cache(cpu);