Commit 93f43731 authored by Tianyang Zhang's avatar Tianyang Zhang Committed by Huacai Chen
Browse files

LoongArch: Add SCHED_MC (Multi-core scheduler) support 



In order to achieve more reasonable load balancing behavior, add
SCHED_MC (Multi-core scheduler) support.

The LLC distribution of LoongArch now is consistent with NUMA node,
the balancing domain of SCHED_MC can effectively reduce the situation
where processes are awakened to smt_sibling.

Co-developed-by: default avatarHongliang Wang <wanghongliang@loongson.cn>
Signed-off-by: default avatarHongliang Wang <wanghongliang@loongson.cn>
Signed-off-by: default avatarTianyang Zhang <zhangtianyang@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 980d4a42

arch/loongarch/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -456,6 +456,15 @@ config SCHED_SMT 
	  Improves scheduler's performance when there are multiple

	  threads in one physical core.



config SCHED_MC

	bool "Multi-core scheduler support"

	depends on SMP

	default y

	help

	  Multi-core scheduler support improves the CPU scheduler's decision

	  making when dealing with multi-core CPU chips at a cost of slightly

	  increased overhead in some places.



config SMP

	bool "Multi-Processing support"

	help

arch/loongarch/include/asm/smp.h

+1 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ extern int smp_num_siblings; 
extern int num_processors;

extern int disabled_cpus;

extern cpumask_t cpu_sibling_map[];

extern cpumask_t cpu_llc_shared_map[];

extern cpumask_t cpu_core_map[];

extern cpumask_t cpu_foreign_map[];

arch/loongarch/include/asm/topology.h

+8 −0
Original line number Diff line number Diff line
@@ -30,6 +30,14 @@ void numa_set_distance(int from, int to, int distance); 
#endif



#ifdef CONFIG_SMP

/*

 * Return cpus that shares the last level cache.

 */

static inline const struct cpumask *cpu_coregroup_mask(int cpu)

{

	return &cpu_llc_shared_map[cpu];

}



#define topology_physical_package_id(cpu)	(cpu_data[cpu].package)

#define topology_core_id(cpu)			(cpu_data[cpu].core)

#define topology_core_cpumask(cpu)		(&cpu_core_map[cpu])

arch/loongarch/kernel/smp.c

+38 −0
Original line number Diff line number Diff line
@@ -46,6 +46,10 @@ EXPORT_SYMBOL(__cpu_logical_map); 
cpumask_t cpu_sibling_map[NR_CPUS] __read_mostly;

EXPORT_SYMBOL(cpu_sibling_map);



/* Representing the last level cache shared map of each logical CPU */

cpumask_t cpu_llc_shared_map[NR_CPUS] __read_mostly;

EXPORT_SYMBOL(cpu_llc_shared_map);



/* Representing the core map of multi-core chips of each logical CPU */

cpumask_t cpu_core_map[NR_CPUS] __read_mostly;

EXPORT_SYMBOL(cpu_core_map);
@@ -63,6 +67,9 @@ EXPORT_SYMBOL(cpu_foreign_map); 
/* representing cpus for which sibling maps can be computed */

static cpumask_t cpu_sibling_setup_map;



/* representing cpus for which llc shared maps can be computed */

static cpumask_t cpu_llc_shared_setup_map;



/* representing cpus for which core maps can be computed */

static cpumask_t cpu_core_setup_map;
@@ -102,6 +109,34 @@ static inline void set_cpu_core_map(int cpu) 
	}

}



static inline void set_cpu_llc_shared_map(int cpu)

{

	int i;



	cpumask_set_cpu(cpu, &cpu_llc_shared_setup_map);



	for_each_cpu(i, &cpu_llc_shared_setup_map) {

		if (cpu_to_node(cpu) == cpu_to_node(i)) {

			cpumask_set_cpu(i, &cpu_llc_shared_map[cpu]);

			cpumask_set_cpu(cpu, &cpu_llc_shared_map[i]);

		}

	}

}



static inline void clear_cpu_llc_shared_map(int cpu)

{

	int i;



	for_each_cpu(i, &cpu_llc_shared_setup_map) {

		if (cpu_to_node(cpu) == cpu_to_node(i)) {

			cpumask_clear_cpu(i, &cpu_llc_shared_map[cpu]);

			cpumask_clear_cpu(cpu, &cpu_llc_shared_map[i]);

		}

	}



	cpumask_clear_cpu(cpu, &cpu_llc_shared_setup_map);

}



static inline void set_cpu_sibling_map(int cpu)

{

	int i;
@@ -406,6 +441,7 @@ int loongson_cpu_disable(void) 
#endif

	set_cpu_online(cpu, false);

	clear_cpu_sibling_map(cpu);

	clear_cpu_llc_shared_map(cpu);

	calculate_cpu_foreign_map();

	local_irq_save(flags);

	irq_migrate_all_off_this_cpu();
@@ -572,6 +608,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus) 
	current_thread_info()->cpu = 0;

	loongson_prepare_cpus(max_cpus);

	set_cpu_sibling_map(0);

	set_cpu_llc_shared_map(0);

	set_cpu_core_map(0);

	calculate_cpu_foreign_map();

#ifndef CONFIG_HOTPLUG_CPU
@@ -613,6 +650,7 @@ asmlinkage void start_secondary(void) 
	loongson_init_secondary();



	set_cpu_sibling_map(cpu);

	set_cpu_llc_shared_map(cpu);

	set_cpu_core_map(cpu);



	notify_cpu_starting(cpu);