Commit 8ae9e2d8 authored by Catalin Marinas's avatar Catalin Marinas
Browse files

Merge branch 'for-next/smt-control' into for-next/core 

* for-next/smt-control:
  : Support SMT control on arm64
  arm64: Kconfig: Enable HOTPLUG_SMT
  arm64: topology: Support SMT control on ACPI based system
  arch_topology: Support SMT control for OF based system
  cpu/SMT: Provide a default topology_is_primary_thread()
parents 8cc14fdc eed4583b

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -250,6 +250,7 @@ config ARM64 
	select HAVE_KRETPROBES

	select HAVE_GENERIC_VDSO

	select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU

	select HOTPLUG_SMT if HOTPLUG_CPU

	select IRQ_DOMAIN

	select IRQ_FORCED_THREADING

	select KASAN_VMALLOC if KASAN

arch/arm64/kernel/topology.c

+54 −0
Original line number Diff line number Diff line
@@ -15,9 +15,11 @@ 
#include <linux/arch_topology.h>

#include <linux/cacheinfo.h>

#include <linux/cpufreq.h>

#include <linux/cpu_smt.h>

#include <linux/init.h>

#include <linux/percpu.h>

#include <linux/sched/isolation.h>

#include <linux/xarray.h>



#include <asm/cpu.h>

#include <asm/cputype.h>
@@ -38,17 +40,28 @@ static bool __init acpi_cpu_is_threaded(int cpu) 
	return !!is_threaded;

}



struct cpu_smt_info {

	unsigned int thread_num;

	int core_id;

};



/*

 * Propagate the topology information of the processor_topology_node tree to the

 * cpu_topology array.

 */

int __init parse_acpi_topology(void)

{

	unsigned int max_smt_thread_num = 1;

	struct cpu_smt_info *entry;

	struct xarray hetero_cpu;

	unsigned long hetero_id;

	int cpu, topology_id;



	if (acpi_disabled)

		return 0;



	xa_init(&hetero_cpu);



	for_each_possible_cpu(cpu) {

		topology_id = find_acpi_cpu_topology(cpu, 0);

		if (topology_id < 0)
@@ -58,6 +71,34 @@ int __init parse_acpi_topology(void) 
			cpu_topology[cpu].thread_id = topology_id;

			topology_id = find_acpi_cpu_topology(cpu, 1);

			cpu_topology[cpu].core_id   = topology_id;



			/*

			 * In the PPTT, CPUs below a node with the 'identical

			 * implementation' flag have the same number of threads.

			 * Count the number of threads for only one CPU (i.e.

			 * one core_id) among those with the same hetero_id.

			 * See the comment of find_acpi_cpu_topology_hetero_id()

			 * for more details.

			 *

			 * One entry is created for each node having:

			 * - the 'identical implementation' flag

			 * - its parent not having the flag

			 */

			hetero_id = find_acpi_cpu_topology_hetero_id(cpu);

			entry = xa_load(&hetero_cpu, hetero_id);

			if (!entry) {

				entry = kzalloc(sizeof(*entry), GFP_KERNEL);

				WARN_ON_ONCE(!entry);



				if (entry) {

					entry->core_id = topology_id;

					entry->thread_num = 1;

					xa_store(&hetero_cpu, hetero_id,

						 entry, GFP_KERNEL);

				}

			} else if (entry->core_id == topology_id) {

				entry->thread_num++;

			}

		} else {

			cpu_topology[cpu].thread_id  = -1;

			cpu_topology[cpu].core_id    = topology_id;
@@ -68,6 +109,19 @@ int __init parse_acpi_topology(void) 
		cpu_topology[cpu].package_id = topology_id;

	}



	/*

	 * This is a short loop since the number of XArray elements is the

	 * number of heterogeneous CPU clusters. On a homogeneous system

	 * there's only one entry in the XArray.

	 */

	xa_for_each(&hetero_cpu, hetero_id, entry) {

		max_smt_thread_num = max(max_smt_thread_num, entry->thread_num);

		xa_erase(&hetero_cpu, hetero_id);

		kfree(entry);

	}



	cpu_smt_set_num_threads(max_smt_thread_num, max_smt_thread_num);

	xa_destroy(&hetero_cpu);

	return 0;

}

#endif

arch/powerpc/include/asm/topology.h

+1 −0
Original line number Diff line number Diff line
@@ -152,6 +152,7 @@ static inline bool topology_is_primary_thread(unsigned int cpu) 
{

	return cpu == cpu_first_thread_sibling(cpu);

}

#define topology_is_primary_thread topology_is_primary_thread



static inline bool topology_smt_thread_allowed(unsigned int cpu)

{

arch/x86/include/asm/topology.h

+1 −1
Original line number Diff line number Diff line
@@ -229,11 +229,11 @@ static inline bool topology_is_primary_thread(unsigned int cpu) 
{

	return cpumask_test_cpu(cpu, cpu_primary_thread_mask);

}

#define topology_is_primary_thread topology_is_primary_thread



#else /* CONFIG_SMP */

static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; }

static inline int topology_max_smt_threads(void) { return 1; }

static inline bool topology_is_primary_thread(unsigned int cpu) { return true; }

static inline unsigned int topology_amd_nodes_per_pkg(void) { return 1; }

#endif /* !CONFIG_SMP */

drivers/base/arch_topology.c

+18 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/cleanup.h>

#include <linux/cpu.h>

#include <linux/cpufreq.h>

#include <linux/cpu_smt.h>

#include <linux/device.h>

#include <linux/of.h>

#include <linux/slab.h>
@@ -508,6 +509,10 @@ core_initcall(free_raw_capacity); 
#endif



#if defined(CONFIG_ARM64) || defined(CONFIG_RISCV)



/* Used to enable the SMT control */

static unsigned int max_smt_thread_num = 1;



/*

 * This function returns the logic cpu number of the node.

 * There are basically three kinds of return values:
@@ -567,6 +572,8 @@ static int __init parse_core(struct device_node *core, int package_id, 
		i++;

	} while (1);



	max_smt_thread_num = max_t(unsigned int, max_smt_thread_num, i);



	cpu = get_cpu_for_node(core);

	if (cpu >= 0) {

		if (!leaf) {
@@ -679,6 +686,17 @@ static int __init parse_socket(struct device_node *socket) 
	if (!has_socket)

		ret = parse_cluster(socket, 0, -1, 0);



	/*

	 * Reset the max_smt_thread_num to 1 on failure. Since on failure

	 * we need to notify the framework the SMT is not supported, but

	 * max_smt_thread_num can be initialized to the SMT thread number

	 * of the cores which are successfully parsed.

	 */

	if (ret)

		max_smt_thread_num = 1;



	cpu_smt_set_num_threads(max_smt_thread_num, max_smt_thread_num);



	return ret;

}