Skip to content
charmOS docs

Domains

include/smp/domain.h View source View on GitHub
NOTE

Definition of a “domain”

Domains are a first-class topology abstraction used to group CPUs by NUMA nodes when present or by a fixed number on UMA systems

The premise: kernels benefit from NUMA awareness, however, the benefits reaped by NUMA also benefit UMA systems. For instance, memory allocators that are NUMA aware get better memory locality AND lower lock contention, however, under UMA, the benefit of lower lock contention, and potentially better cache performance are helpful.

Because NUMA logic already exists, we can reuse the logic that handles NUMA systems with UMA systems, and reap the benefits without NUMA.

Structs

Section titled “Structs”

domain

Section titled “domain”
struct domain (7 fields) source
§ size_t id
§ size_t num_cores
§ struct core **cores
§ struct numa_node *associated_node
§ struct slab_domain *slab_domain
§ struct domain_buddy *domain_buddy
§ struct cpu_mask cpu_mask

Functions

Section titled “Functions”

domain_init

Section titled “domain_init”
void domain_init(void)
source

domain_create_cpu_mask

Section titled “domain_create_cpu_mask”
struct cpu_mask * domain_create_cpu_mask(struct domain *domain)
source

domain_set_cpu_mask

Section titled “domain_set_cpu_mask”
void domain_set_cpu_mask(struct cpu_mask *mask, struct domain *domain)
source

domain_idle

Section titled “domain_idle”
bool domain_idle(struct domain *domain)
source

numa_node_for_cpu

Section titled “numa_node_for_cpu”
numa_node_t numa_node_for_cpu(cpu_id_t cpu)
source

domain_for_cpu

Section titled “domain_for_cpu”
domain_id_t domain_for_cpu(cpu_id_t cpu)
source

domain_init_after_smp

Section titled “domain_init_after_smp”
void domain_init_after_smp(void)
source

domain_caller_verify

Section titled “domain_caller_verify”
void domain_caller_verify(enum topology_caller caller)
source

domain_dump

Section titled “domain_dump”
void domain_dump(void)
source

domain_local

Section titled “domain_local”
struct domain * domain_local(enum topology_caller c)
source

domain_local_id

Section titled “domain_local_id”
domain_id_t domain_local_id(enum topology_caller c)
source

Macros

Section titled “Macros”

CORES_PER_DOMAIN

Section titled “CORES_PER_DOMAIN”
#define CORES_PER_DOMAIN 4
source

For UMA: TODO: we likely want this to be command line configurable/adjusted at boot time

domain_for_each_domain

Section titled “domain_for_each_domain”
#define domain_for_each_domain(dom_)
source
Expansion
#define domain_for_each_domain(dom_) \
    for (domain_id_t __dom_idx = 0; \
         __dom_idx < global.domain_count && \
         (((dom_) = global.domains[__dom_idx]), true); \
         __dom_idx++)

domain_for_each_domain_id

Section titled “domain_for_each_domain_id”
#define domain_for_each_domain_id(id_)
source
Expansion
#define domain_for_each_domain_id(id_) \
    for (domain_id_t __dom_id_idx = 0; \
         __dom_id_idx < global.domain_count && \
         (((id_) = global.domains[__dom_id_idx]->id), true); \
         __dom_id_idx++)

domain_for_each_core

Section titled “domain_for_each_core”
#define domain_for_each_core(pos_, dom_)
source
Expansion
#define domain_for_each_core(pos_, dom_) \
    for (size_t __core_idx = 0; __core_idx < (dom_)->num_cores && \
                                (((pos_) = (dom_)->cores[__core_idx]), true); \
         __core_idx++)

domain_for_each_core_id

Section titled “domain_for_each_core_id”
#define domain_for_each_core_id(pos_, dom_)
source
Expansion
#define domain_for_each_core_id(pos_, dom_) \
    for (size_t __core_id_idx = 0; \
         __core_id_idx < (dom_)->num_cores && \
         (((pos_) = (dom_)->cores[__core_id_idx]->id), true); \
         __core_id_idx++)

domain_for_each_core_local

Section titled “domain_for_each_core_local”
#define domain_for_each_core_local(pos_, clr_)
source
Expansion
#define domain_for_each_core_local(pos_, clr_) \
    domain_for_each_core(pos_, smp_core(clr_)->domain)