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authorDietmar Eggemann <dietmar.eggemann@arm.com>2019-11-29 16:23:02 +0100
committerRussell King <rmk+kernel@armlinux.org.uk>2019-12-06 11:51:02 +0000
commitff98a5f624d2910de050f1fc7f2a32769da86b51 (patch)
tree81d101e4e68cfd1568908b8fdf2f81c0d35b19b6 /arch
parent1a70cf0e7ee6e73aa29c2dd4dd8d3d38c48d5946 (diff)
ARM: 8943/1: Fix topology setup in case of CPU hotplug for CONFIG_SCHED_MC
Commit ca74b316df96 ("arm: Use common cpu_topology structure and functions.") changed cpu_coregroup_mask() from the ARM32 specific implementation in arch/arm/include/asm/topology.h to the one shared with ARM64 and RISCV in drivers/base/arch_topology.c. Currently on ARM32 (TC2 w/ CONFIG_SCHED_MC) the task scheduler setup code (w/ CONFIG_SCHED_DEBUG) shows this during CPU hotplug: ERROR: groups don't span domain->span It happens to CPUs of the cluster of the CPU which gets hot-plugged out on scheduler domain MC. Turns out that the shared cpu_coregroup_mask() requires that the hot-plugged CPU is removed from the core_sibling mask via remove_cpu_topology(). Otherwise the 'is core_sibling subset of cpumask_of_node()' doesn't work. In this case the task scheduler has to deal with cpumask_of_node instead of core_sibling which is wrong on scheduler domain MC. e.g. CPU3 hot-plugged out on TC2 [cluster0: 0,3-4 cluster1: 1-2]: cpu_coregroup_mask(): CPU3 cpumask_of_node=0-2,4 core_sibling=0,3-4 ^ should be: cpu_coregroup_mask(): CPU3 cpumask_of_node=0-2,4 core_sibling=0,4 Add remove_cpu_topology() to __cpu_disable() to remove the CPU from the topology masks in case of a CPU hotplug out operation. At the same time tweak store_cpu_topology() slightly so it will call update_siblings_masks() in case of CPU hotplug in operation via secondary_start_kernel()->smp_store_cpu_info(). This aligns the ARM32 implementation with the ARM64 one. Guarding remove_cpu_topology() with CONFIG_GENERIC_ARCH_TOPOLOGY is necessary since some Arm32 defconfigs (aspeed_g5_defconfig, milbeaut_m10v_defconfig, spear13xx_defconfig) specify an explicit # CONFIG_ARM_CPU_TOPOLOGY is not set w/ ./arch/arm/Kconfig: select GENERIC_ARCH_TOPOLOGY if ARM_CPU_TOPOLOGY Fixes: ca74b316df96 ("arm: Use common cpu_topology structure and functions") Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> Reviewed-by: Lukasz Luba <lukasz.luba@arm.com> Tested-by: Lukasz Luba <lukasz.luba@arm.com> Tested-by: Ondrej Jirman <megous@megous.com> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/kernel/smp.c4
-rw-r--r--arch/arm/kernel/topology.c10
2 files changed, 9 insertions, 5 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 4b0bab2607e4..46e1be9e57a8 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -240,6 +240,10 @@ int __cpu_disable(void)
if (ret)
return ret;
+#ifdef CONFIG_GENERIC_ARCH_TOPOLOGY
+ remove_cpu_topology(cpu);
+#endif
+
/*
* Take this CPU offline. Once we clear this, we can't return,
* and we must not schedule until we're ready to give up the cpu.
diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
index 3a4dde081c13..b5adaf744630 100644
--- a/arch/arm/kernel/topology.c
+++ b/arch/arm/kernel/topology.c
@@ -196,9 +196,8 @@ void store_cpu_topology(unsigned int cpuid)
struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
unsigned int mpidr;
- /* If the cpu topology has been already set, just return */
- if (cpuid_topo->core_id != -1)
- return;
+ if (cpuid_topo->package_id != -1)
+ goto topology_populated;
mpidr = read_cpuid_mpidr();
@@ -231,14 +230,15 @@ void store_cpu_topology(unsigned int cpuid)
cpuid_topo->package_id = -1;
}
- update_siblings_masks(cpuid);
-
update_cpu_capacity(cpuid);
pr_info("CPU%u: thread %d, cpu %d, socket %d, mpidr %x\n",
cpuid, cpu_topology[cpuid].thread_id,
cpu_topology[cpuid].core_id,
cpu_topology[cpuid].package_id, mpidr);
+
+topology_populated:
+ update_siblings_masks(cpuid);
}
static inline int cpu_corepower_flags(void)