Hi Jeremy,
I have tested the patch with the newest UEFI. It prints the below error:
[ 4.017371] BUG: arch topology borken
[ 4.021069] BUG: arch topology borken
[ 4.024764] BUG: arch topology borken
[ 4.028460] BUG: arch topology borken
[ 4.032153] BUG: arch topology borken
[ 4.035849] BUG: arch topology borken
[ 4.039543] BUG: arch topology borken
[ 4.043239] BUG: arch topology borken
[ 4.046932] BUG: arch topology borken
[ 4.050629] BUG: arch topology borken
[ 4.054322] BUG: arch topology borken
I checked the code and found that the newest UEFI set PPTT physical_package_flag on a physical package node and
the NUMA domain (SRAT domains) starts from the layer of DIE. (The topology of our board is core->cluster->die->package).
When the kernel starts to build sched_domain, the multi-core sched_domain contains all the cores within a package,
and the lowest NUMA sched_domain contains all the cores within a die. But the kernel requires that the multi-core
sched_domain should be a subset of the lowest NUMA sched_domain, so the BUG info is printed.
If we modify the UEFI to make NUMA sched_domain start from the layer of package, then all the topology information
within the package will be discarded. I think we need to build the multi-core sched_domain using the cores within
the cluster instead of the cores within the package. I think that's what 'multi-core' means. Multi cores form a cluster. I guess.
If we build the multi-core sched_domain using the cores within a cluster, I think we need to add fields in struct cpu_topology
to record which cores are in each cluster.
Thanks,
Xiongfeng
On 2018/1/13 8:59, Jeremy Linton wrote:
Propagate the topology information from the PPTT tree to the
cpu_topology array. We can get the thread id, core_id and
cluster_id by assuming certain levels of the PPTT tree correspond
to those concepts. The package_id is flagged in the tree and can be
found by calling find_acpi_cpu_topology_package() which terminates
its search when it finds an ACPI node flagged as the physical
package. If the tree doesn't contain enough levels to represent
all of the requested levels then the root node will be returned
for all subsequent levels.
Cc: Juri Lelli <juri.lelli@xxxxxxx>
Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
---
arch/arm64/kernel/topology.c | 46 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 45 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 7b06e263fdd1..ce8ec7fd6b32 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -11,6 +11,7 @@
* for more details.
*/
+#include <linux/acpi.h>
#include <linux/arch_topology.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
@@ -22,6 +23,7 @@
#include <linux/sched.h>
#include <linux/sched/topology.h>
#include <linux/slab.h>
+#include <linux/smp.h>
#include <linux/string.h>
#include <asm/cpu.h>
@@ -300,6 +302,46 @@ static void __init reset_cpu_topology(void)
}
}
+#ifdef CONFIG_ACPI
+/*
+ * Propagate the topology information of the processor_topology_node tree to the
+ * cpu_topology array.
+ */
+static int __init parse_acpi_topology(void)
+{
+ bool is_threaded;
+ int cpu, topology_id;
+
+ is_threaded = read_cpuid_mpidr() & MPIDR_MT_BITMASK;
+
+ for_each_possible_cpu(cpu) {
+ topology_id = find_acpi_cpu_topology(cpu, 0);
+ if (topology_id < 0)
+ return topology_id;
+
+ if (is_threaded) {
+ cpu_topology[cpu].thread_id = topology_id;
+ topology_id = find_acpi_cpu_topology(cpu, 1);
+ cpu_topology[cpu].core_id = topology_id;
+ topology_id = find_acpi_cpu_topology_package(cpu);
+ cpu_topology[cpu].package_id = topology_id;
+ } else {
+ cpu_topology[cpu].thread_id = -1;
+ cpu_topology[cpu].core_id = topology_id;
+ topology_id = find_acpi_cpu_topology_package(cpu);
+ cpu_topology[cpu].package_id = topology_id;
+ }
+ }
+
+ return 0;
+}
+
+#else
+static inline int __init parse_acpi_topology(void)
+{
+ return -EINVAL;
+}
+#endif
void __init init_cpu_topology(void)
{
@@ -309,6 +351,8 @@ void __init init_cpu_topology(void)
* Discard anything that was parsed if we hit an error so we
* don't use partial information.
*/
- if (of_have_populated_dt() && parse_dt_topology())
+ if ((!acpi_disabled) && parse_acpi_topology())
+ reset_cpu_topology();
+ else if (of_have_populated_dt() && parse_dt_topology())
reset_cpu_topology();
}