diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2023-07-05 16:51:42 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2023-08-02 22:49:43 +1000 |
| commit | 73c58e7e14126466701705820c4eb47daddc357d (patch) | |
| tree | d07ae0e1b3836a96e7d4477fa7cfb6b8bf23059c /arch/powerpc | |
| parent | 3b3a4d0fe542b8c2295cf934305b45a14e224beb (diff) | |
powerpc: Add HOTPLUG_SMT support
Add support for HOTPLUG_SMT, which enables the generic sysfs SMT support
files in /sys/devices/system/cpu/smt, as well as the "nosmt" boot
parameter.
Implement the recently added hooks to allow partial SMT states, allow
any number of threads per core.
Tie the config symbol to HOTPLUG_CPU, which enables it on the major
platforms that support SMT. If there are other platforms that want the
SMT support that can be tweaked in future.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
[ldufour: remove topology_smt_supported]
[ldufour: remove topology_smt_threads_supported]
[ldufour: select CONFIG_SMT_NUM_THREADS_DYNAMIC]
[ldufour: update kernel-parameters.txt]
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Link: https://msgid.link/20230705145143.40545-10-ldufour@linux.ibm.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/Kconfig | 2 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/topology.h | 15 | ||||
| -rw-r--r-- | arch/powerpc/kernel/smp.c | 8 |
3 files changed, 24 insertions, 1 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 0b1172cbeccb..aef38d2ca542 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -272,6 +272,8 @@ config PPC select HAVE_SYSCALL_TRACEPOINTS select HAVE_VIRT_CPU_ACCOUNTING select HAVE_VIRT_CPU_ACCOUNTING_GEN + select HOTPLUG_SMT if HOTPLUG_CPU + select SMT_NUM_THREADS_DYNAMIC select HUGETLB_PAGE_SIZE_VARIABLE if PPC_BOOK3S_64 && HUGETLB_PAGE select IOMMU_HELPER if PPC64 select IRQ_DOMAIN diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h index 8a4d4f4d9749..f4e6f2dd04b7 100644 --- a/arch/powerpc/include/asm/topology.h +++ b/arch/powerpc/include/asm/topology.h @@ -143,5 +143,20 @@ static inline int cpu_to_coregroup_id(int cpu) #endif #endif +#ifdef CONFIG_HOTPLUG_SMT +#include <linux/cpu_smt.h> +#include <asm/cputhreads.h> + +static inline bool topology_is_primary_thread(unsigned int cpu) +{ + return cpu == cpu_first_thread_sibling(cpu); +} + +static inline bool topology_smt_thread_allowed(unsigned int cpu) +{ + return cpu_thread_in_core(cpu) < cpu_smt_num_threads; +} +#endif + #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_TOPOLOGY_H */ diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index fbbb695bae3d..b9f0f8f11c37 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -1087,7 +1087,7 @@ static int __init init_big_cores(void) void __init smp_prepare_cpus(unsigned int max_cpus) { - unsigned int cpu; + unsigned int cpu, num_threads; DBG("smp_prepare_cpus\n"); @@ -1154,6 +1154,12 @@ void __init smp_prepare_cpus(unsigned int max_cpus) if (smp_ops && smp_ops->probe) smp_ops->probe(); + + // Initalise the generic SMT topology support + num_threads = 1; + if (smt_enabled_at_boot) + num_threads = smt_enabled_at_boot; + cpu_smt_set_num_threads(num_threads, threads_per_core); } void smp_prepare_boot_cpu(void) |