Commit a05f0e5b authored Jan 29, 2020 by Srikar Dronamraju Committed by Michael Ellerman Mar 04, 2020

powerpc/smp: Use nid as fallback for package_id



package_id is to match cores that are part of the same chip. On
PowerNV machines, package_id defaults to chip_id. However ibm,chip_id
property is not present in device-tree of PowerVM LPARs. Hence lscpu
output shows one core per socket and multiple cores.

To overcome this, use nid as the package_id on PowerVM LPARs.

Before the patch:

  Architecture:        ppc64le
  Byte Order:          Little Endian
  CPU(s):              128
  On-line CPU(s) list: 0-127
  Thread(s) per core:  8
  Core(s) per socket:  1                     <----------------------
  Socket(s):           16                    <----------------------
  NUMA node(s):        2
  Model:               2.2 (pvr 004e 0202)
  Model name:          POWER9 (architected), altivec supported
  Hypervisor vendor:   pHyp
  Virtualization type: para
  L1d cache:           32K
  L1i cache:           32K
  L2 cache:            512K
  L3 cache:            10240K
  NUMA node0 CPU(s):   0-63
  NUMA node1 CPU(s):   64-127
  #
  # cat /sys/devices/system/cpu/cpu0/topology/physical_package_id
  -1

After the patch:

  Architecture:        ppc64le
  Byte Order:          Little Endian
  CPU(s):              128
  On-line CPU(s) list: 0-127
  Thread(s) per core:  8                     <---------------------
  Core(s) per socket:  8                     <---------------------
  Socket(s):           2
  NUMA node(s):        2
  Model:               2.2 (pvr 004e 0202)
  Model name:          POWER9 (architected), altivec supported
  Hypervisor vendor:   pHyp
  Virtualization type: para
  L1d cache:           32K
  L1i cache:           32K
  L2 cache:            512K
  L3 cache:            10240K
  NUMA node0 CPU(s):   0-63
  NUMA node1 CPU(s):   64-127
  #
  # cat /sys/devices/system/cpu/cpu0/topology/physical_package_id
  0

Now lscpu output is more in line with the system configuration.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
[mpe: Use pkg_id instead of ppid, tweak change log and comment]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200129135121.24617-1-srikar@linux.vnet.ibm.com

parent 532d43a7

arch/powerpc/include/asm/topology.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -134,7 +134,13 @@ static inline void shared_proc_topology_init(void) {}
		#ifdef CONFIG_PPC64
		#include <asm/smp.h>

		#ifdef CONFIG_PPC_SPLPAR
		int get_physical_package_id(int cpu);
		#define topology_physical_package_id(cpu) (get_physical_package_id(cpu))
		#else
		#define topology_physical_package_id(cpu) (cpu_to_chip_id(cpu))
		#endif

		#define topology_sibling_cpumask(cpu) (per_cpu(cpu_sibling_map, cpu))
		#define topology_core_cpumask(cpu) (per_cpu(cpu_core_map, cpu))
		#define topology_core_id(cpu) (cpu_to_core_id(cpu))

arch/powerpc/kernel/smp.c

+27 −3

Original line number	Diff line number	Diff line
		@@ -1185,10 +1185,34 @@ static inline void add_cpu_to_smallcore_masks(int cpu)
		}
		}

		int get_physical_package_id(int cpu)
		{
		int pkg_id = cpu_to_chip_id(cpu);

		#ifdef CONFIG_PPC_SPLPAR
		/*
		* If the platform is PowerNV or Guest on KVM, ibm,chip-id is
		* defined. Hence we would return the chip-id as the result of
		* get_physical_package_id.
		*/
		if (pkg_id == -1 && firmware_has_feature(FW_FEATURE_LPAR)) {
		struct device_node *np = of_get_cpu_node(cpu, NULL);

		if (np) {
		pkg_id = of_node_to_nid(np);
		of_node_put(np);
		}
		}
		#endif /* CONFIG_PPC_SPLPAR */

		return pkg_id;
		}
		EXPORT_SYMBOL_GPL(get_physical_package_id);

		static void add_cpu_to_masks(int cpu)
		{
		int first_thread = cpu_first_thread_sibling(cpu);
		int chipid = cpu_to_chip_id(cpu);
		int pkg_id = get_physical_package_id(cpu);
		int i;

		/*
		@@ -1217,11 +1241,11 @@ static void add_cpu_to_masks(int cpu)
		for_each_cpu(i, cpu_l2_cache_mask(cpu))
		set_cpus_related(cpu, i, cpu_core_mask);

		if (chipid == -1)
		if (pkg_id == -1)
		return;

		for_each_cpu(i, cpu_online_mask)
		if (cpu_to_chip_id(i) == chipid)
		if (get_physical_package_id(i) == pkg_id)
		set_cpus_related(cpu, i, cpu_core_mask);
		}

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