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xo-gc: refactor: move some aux method impls to GCObjectStore

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This commit is contained in:
Roland Conybeare 2026-04-02 21:56:12 -04:00
commit 08b313f25c
9 changed files with 131 additions and 34 deletions
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23
include/xo/gc/GCObjectStore.hpp
View file

@ -26,6 +26,8 @@ namespace xo {
public:
explicit GCObjectStore(const GCObjectStoreConfig & cfg);
const GCObjectStoreConfig & config() const noexcept { return config_; }
const DArena * get_space(role r, Generation g) const noexcept { return space_[r][g]; }
DArena * get_space(role r, Generation g) noexcept { return space_[r][g]; }
DArena * from_space(Generation g) noexcept { return get_space(role::from_space(), g); }
@ -53,6 +55,27 @@ namespace xo {
/** Call @p visitor for each memory pool owned by this store **/
void visit_pools(const MemorySizeVisitor & visitor) const;
/** true iff address @p addr allocated from this collector
* in role @p r (according to current GC state)
**/
bool contains(role r, const void * addr) const noexcept;
/** true iff address @p addr allocated from this collector and currently live
* in role @p r (according to current GC state)
*
* (i.e. in [lo,free) for an arena)
**/
bool contains_allocated(role r, const void * addr) const noexcept;
/** true iff {@p alloc_hdr, @p object_data} should move for
* a collection of all generations strictly younger than @p upto.
*
* Require: runstate_.is_running()
**/
bool check_move_policy(Generation upto,
header_type alloc_hdr,
void * gco_data) const noexcept;
/** For each generation g in [0 ,.., upto)
* swap arenas assigned to {to-space, from-space}.
* Invoked once at the beginning of each gc cycle.

32
include/xo/gc/GCObjectStoreConfig.hpp
View file

@ -5,6 +5,8 @@
#pragma once
#include "generation.hpp"
#include "object_age.hpp"
#include <xo/arena/DArena.hpp>
namespace xo {
@ -15,8 +17,30 @@ namespace xo {
public:
GCObjectStoreConfig(const ArenaConfig & arena_cfg,
std::uint32_t ngen,
std::uint32_t nsurvive,
bool debug_flag);
/** generation that would contain an object that has survived
* @p age collections. Equals the number of times object
* has been promoted.
*
* Must be consistent
**/
Generation age2gen(object_age age) const noexcept {
return Generation(age % n_survive_threshold_);
}
/** age threshold for promotion to generation @p g **/
uint32_t promotion_threshold(Generation g) const noexcept {
// TODO: may consider replacing with table-lookup
// Require: if two distinct ages promote to some gen g at the same time,
// then they also promote to gen g+k at the same time for all k>0.
return g * n_survive_threshold_;
}
public:
/** Configuration for collector spaces.
* Will have (2 x G) of these,
@ -27,8 +51,16 @@ namespace xo {
* - arena_config_.store_header_flag_ must be true
**/
ArenaConfig arena_config_;
/** number of generations in use. Same as @ref X1CollectorConfig::n_generation_ **/
std::uint32_t n_generation_ = 0;
/** Number of promotion steps.
* An object that survives this number of collections
* advances to the next generation.
**/
std::uint32_t n_survive_threshold_ = 2;
/** true to enable debug logging **/
bool debug_flag_ = false;
};

20
include/xo/gc/MutationLogConfig.hpp
View file

@ -5,6 +5,7 @@
#pragma once
#include "object_age.hpp"
#include "generation.hpp"
#include <cstddef>
#include <cstdint>
@ -16,10 +17,25 @@ namespace xo {
class MutationLogConfig {
public:
MutationLogConfig(std::uint32_t ngen,
#ifdef OBSOLETE // in GCObjectStore
std::uint32_t survive,
#endif
std::size_t mlog_z,
bool debug_flag);
#ifdef OBSOLETE
/** generation that would contain an object that has survived
* @p age collections. Equals the number of times object
* has been promoted.
*
* Must be consistent
**/
Generation age2gen(object_age age) const noexcept {
return Generation(age % n_survive_threshold_);
}
#endif
#ifdef OBSOLETE
/** age threshold for promotion to generation @p g **/
uint32_t promotion_threshold(Generation g) const noexcept {
@ -29,7 +45,7 @@ namespace xo {
return g * n_survive_threshold_;
}
#endif
public:
/** number of generations in use.
@ -37,11 +53,13 @@ namespace xo {
**/
std::uint32_t n_generation_ = 0;
#ifdef OBSOLETE
/** Number of promotion steps.
* An object that survives this number of collections
* advances to the next generation.
**/
uint32_t n_survive_threshold_ = 2;
#endif
/** storage for xgen pointer bookkeeping (aka remembered sets).
* Use 3x this value per generation

7
include/xo/gc/X1CollectorConfig.hpp
View file

@ -42,24 +42,27 @@ namespace xo {
GCObjectStoreConfig gco_store_config() const noexcept {
return GCObjectStoreConfig(arena_config_,
n_generation_,
n_survive_threshold_,
debug_flag_);
}
/** fetch configuration for mutation log store **/
MutationLogConfig mlog_config() const noexcept {
return MutationLogConfig(n_generation_,
#ifdef OBSOLETE
n_survive_threshold_,
#endif
mutation_log_z_,
debug_flag_);
}
Generation age2gen(object_age age) const noexcept {
return Generation(age % n_survive_threshold_);
return this->gco_store_config().age2gen(age);
}
/** age threshold for promotion to generation @p g **/
uint32_t promotion_threshold(Generation g) const noexcept {
return mlog_config().promotion_threshold(g);
return this->gco_store_config().promotion_threshold(g);
}
public:

33
src/gc/DX1Collector.cpp
View file

@ -124,18 +124,13 @@ namespace xo {
bool
DX1Collector::contains(role r, const void * addr) const noexcept
{
return !(this->generation_of(r, addr).is_sentinel());
return gco_store_.contains(r, addr);
}
bool
DX1Collector::contains_allocated(role r, const void * addr) const noexcept
{
Generation g = this->generation_of(r, addr);
if (g.is_sentinel())
return false;
return this->get_space(r, g)->contains_allocated(addr);
return gco_store_.contains_allocated(r, addr);
}
Generation
@ -212,16 +207,6 @@ namespace xo {
DX1Collector::mutation_log_entries() const noexcept
{
return mlog_state_.mutation_log_entries();
#ifdef MOVED
size_type z = 0;
for (Generation gj{0}; gj + 1 < config_.n_generation_; ++gj) {
z += mlog_[role::to_space()][gj]->size();
}
return z;
#endif
}
namespace {
@ -1397,19 +1382,11 @@ namespace xo {
DX1Collector::check_move_policy(header_type alloc_hdr,
void * object_data) const noexcept
{
(void)object_data;
// when gc is moving objects, to- and from- spaces have been
// reversed: forwarding pointers are located in from-space and
// refer to to-space.
object_age age = this->header2age(alloc_hdr);
Generation g = config_.age2gen(age);
assert(runstate_.is_running());
return (g < runstate_.gc_upto());
return gco_store_.check_move_policy(runstate_.gc_upto(),
alloc_hdr,
object_data);
}
auto

40
src/gc/GCObjectStore.cpp
View file

@ -133,10 +133,48 @@ namespace xo {
}
}
bool
GCObjectStore::contains(role r, const void * addr) const noexcept
{
return !(this->generation_of(r, addr).is_sentinel());
}
bool
GCObjectStore::contains_allocated(role r, const void * addr) const noexcept
{
Generation g = this->generation_of(r, addr);
if (g.is_sentinel())
return false;
return this->get_space(r, g)->contains_allocated(addr);
}
bool
GCObjectStore::check_move_policy(Generation upto,
header_type alloc_hdr,
void * object_data) const noexcept
{
(void)object_data;
// when gc is moving objects, to- and from- spaces have been
// reversed: forwarding pointers are located in from-space and
// refer to to-space.
object_age age = this->header2age(alloc_hdr);
Generation g = config_.age2gen(age);
//assert(runstate_.is_running());
return (g < upto);
}
void
GCObjectStore::swap_roles(Generation upto) noexcept
{
scope log(XO_DEBUG(config_.debug_flag_), xtag("upto", upto));
scope log(XO_DEBUG(config_.debug_flag_),
xtag("upto", upto));
for (Generation g = Generation{0}; g < upto; ++g) {
log && log("swap roles", xtag("g", g));

2
src/gc/GCObjectStoreConfig.cpp
View file

@ -10,9 +10,11 @@ namespace xo {
GCObjectStoreConfig::GCObjectStoreConfig(const ArenaConfig & arena_cfg,
std::uint32_t ngen,
std::uint32_t nsurvive,
bool debug_flag)
: arena_config_{arena_cfg},
n_generation_{ngen},
n_survive_threshold_{nsurvive},
debug_flag_{debug_flag}
{}

4
src/gc/MutationLogConfig.cpp
View file

@ -9,11 +9,15 @@ namespace xo {
namespace mm {
MutationLogConfig::MutationLogConfig(std::uint32_t ngen,
#ifdef OBSOLETE
std::uint32_t survive,
#endif
std::size_t mlog_z,
bool debug_flag)
: n_generation_{ngen},
#ifdef OBSOLETE
n_survive_threshold_{survive},
#endif
mutation_log_z_{mlog_z},
debug_flag_{debug_flag}
{}

4
src/gc/MutationLogState.cpp
View file

@ -426,8 +426,8 @@ namespace xo {
bool need_mlog_entry
= ((child_gen_to + 1 < config_.n_generation_)
&& (config_.promotion_threshold(parent_gen_to)
> config_.promotion_threshold(child_gen_to)));
&& (gco_store.config().promotion_threshold(parent_gen_to)
> gco_store.config().promotion_threshold(child_gen_to)));
if (need_mlog_entry) {
// 1. P->C pointer is still cross-age (xage), and