1113 lines
40 KiB
C++
1113 lines
40 KiB
C++
/** @file GCObjectStore.cpp
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*
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* @author Roland Conybeare, Apr 2026
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**/
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#include "GCObjectStore.hpp"
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#include "GCObjectStoreVisitor.hpp"
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#include "X1VerifyStats.hpp"
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#include <xo/object2/Dictionary.hpp>
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#include <xo/object2/Array.hpp>
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#include <xo/object2/Integer.hpp>
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#include <xo/object2/Boolean.hpp>
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#include <xo/stringtable2/String.hpp>
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#include <xo/arena/DArenaIterator.hpp>
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#include <xo/arena/backtrace.hpp>
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#include <xo/facet/TypeRegistry.hpp>
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#include <xo/indentlog/scope.hpp>
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#include <cassert>
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#include <unistd.h> // for ::getpagesize()
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namespace xo {
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using xo::scm::DDictionary;
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using xo::scm::DArray;
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using xo::scm::DString;
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using xo::scm::DInteger;
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using xo::mm::DArena;
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using xo::facet::TypeRegistry;
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using xo::reflect::typeseq;
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namespace mm {
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GCObjectStore::GCObjectStore(const GCObjectStoreConfig & cfg,
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X1VerifyStats * p_verify_stats)
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: config_{cfg}, p_verify_stats_{p_verify_stats}
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{
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assert(config_.arena_config_.header_.size_bits_ +
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config_.arena_config_.header_.age_bits_ +
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config_.arena_config_.header_.tseq_bits_ <= 64);
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size_t page_z = getpagesize();
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this->_init_object_types(page_z);
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this->_init_space();
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}
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void
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GCObjectStore::_init_object_types(std::size_t page_z)
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{
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/* 1MB reserved address space enough for up to 128k distinct types.
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* In this case don't want to use hugepages since actual #of types
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* likely << .size/8
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*/
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this->object_types_
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= ObjectTypeTable::map(ArenaConfig{.name_ = "x1-object-types",
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.size_ = config_.object_types_z_,
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.hugepage_z_ = page_z,
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.store_header_flag_ = false});
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}
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void
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GCObjectStore::_init_space()
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{
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assert(c_n_role == 2);
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for (uint32_t igen = 0, ngen = config_.n_generation_; igen < ngen; ++igen) {
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if (igen < c_max_generation) {
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{
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char buf[40];
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snprintf(buf, sizeof(buf), "x1-space-G%u-a", igen);
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this->space_storage_[0][igen]
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= DArena::map(config_.arena_config_.with_name(std::string(buf)));
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}
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{
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char buf[40];
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snprintf(buf, sizeof(buf), "x1-space-G%u-b", igen);
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this->space_storage_[1][igen]
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= DArena::map(config_.arena_config_.with_name(std::string(buf)));
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}
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this->space_[Role::to_space()][igen] = &space_storage_[0][igen];
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this->space_[Role::from_space()][igen] = &space_storage_[1][igen];
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} else {
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assert(false);
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}
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}
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for (uint32_t igen = config_.n_generation_; igen < c_max_generation; ++igen) {
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this->space_[Role::to_space()][igen] = nullptr;
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this->space_[Role::from_space()][igen] = nullptr;
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}
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if (config_.n_generation_ == 2) {
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assert(this->get_space(Role::to_space(), Generation{2}) == nullptr);
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}
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}
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bool
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GCObjectStore::is_type_installed(typeseq tseq) const noexcept
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{
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if (tseq.is_sentinel()
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|| static_cast<ObjectTypeTable::size_type>(tseq.seqno()) > object_types_.size()) {
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return false;
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}
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const ObjectTypeSlot & slot = object_types_[tseq.seqno()];
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return slot.is_occupied();
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}
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AGCObject *
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GCObjectStore::lookup_type(typeseq tseq) const noexcept
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{
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scope log(XO_DEBUG(false));
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if (tseq.is_sentinel()
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|| (static_cast<ObjectTypeTable::size_type>(tseq.seqno())
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> object_types_.size())) {
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// LCOV_EXCL_START
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log.retroactively_enable("out-of-bounds",
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xtag("tseq", tseq),
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xtag("tname", TypeRegistry::id2name(tseq)));
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log(xtag("types.size", object_types_.size()),
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xtag("types.allocated", object_types_.store()->allocated()),
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xtag("types.committed", object_types_.store()->committed()),
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xtag("types.lo", object_types_.store()->lo_),
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xtag("types.limit", object_types_.store()->limit_),
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xtag("types.hi", object_types_.store()->hi_));
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return nullptr;
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// LCOV_EXCL_STOP
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}
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const ObjectTypeSlot & slot = object_types_[tseq.seqno()];
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if (slot.is_null()) {
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// LCOV_EXCL_START
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log.retroactively_enable("null-vtable",
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xtag("tseq", tseq),
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xtag("tname", TypeRegistry::id2name(tseq)));
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assert(false);
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return nullptr;
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// LCOV_EXCL_STOP
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}
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return slot.iface();
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}
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Generation
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GCObjectStore::generation_of(Role r, const void * addr) const noexcept
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{
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for (Generation gi{0}; gi < config_.n_generation_; ++gi) {
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const DArena * arena = this->get_space(r, gi);
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if (arena->contains(addr))
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return gi;
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}
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return Generation::sentinel();
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}
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AllocError
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GCObjectStore::last_error() const noexcept
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{
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return this->get_space(Role::to_space(), Generation{0})->last_error();
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}
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auto
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GCObjectStore::header2size(header_type hdr) const noexcept -> size_type
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{
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uint32_t z = config_.arena_config_.header_.size(hdr);
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return z;
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}
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object_age
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GCObjectStore::header2age(header_type hdr) const noexcept
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{
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uint32_t age = config_.arena_config_.header_.age(hdr);
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assert(age < c_max_object_age);
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return object_age(age);
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}
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uint32_t
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GCObjectStore::header2tseq(header_type hdr) const noexcept
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{
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uint32_t tseq = config_.arena_config_.header_.tseq(hdr);
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return tseq;
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}
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bool
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GCObjectStore::is_forwarding_header(header_type hdr) const noexcept
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{
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/** forwarding pointer encoded as sentinel tseq **/
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return config_.arena_config_.header_.is_forwarding_tseq(hdr);
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}
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AllocInfo
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GCObjectStore::alloc_info(value_type mem) const noexcept {
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for (Role ri : Role::all()) {
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for (Generation gj{0}; gj < config_.n_generation_; ++gj) {
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const DArena * arena = this->get_space(ri, gj);
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assert(arena);
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if (arena->contains(mem)) {
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return arena->alloc_info(mem);
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}
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}
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}
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// deliberately attempt on nursery to-space, to capture error info + return sentinel
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return this->get_space(Role::to_space(), Generation{0})->alloc_info(mem);
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}
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void
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GCObjectStore::visit_pools(const MemorySizeVisitor & visitor) const
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{
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for (uint32_t j = 0; j < config_.n_generation_; ++j) {
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for (uint32_t i = 0; i < c_n_role; ++i) {
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space_storage_[i][j].visit_pools(visitor);
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}
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}
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object_types_.visit_pools(visitor);
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}
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bool
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GCObjectStore::contains(Role r, const void * addr) const noexcept
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{
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return !(this->generation_of(r, addr).is_sentinel());
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}
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bool
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GCObjectStore::contains_allocated(Role r, const void * addr) const noexcept
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{
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Generation g = this->generation_of(r, addr);
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if (g.is_sentinel())
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return false;
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return this->get_space(r, g)->contains_allocated(addr);
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}
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bool
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GCObjectStore::report_object_types(obj<AAllocator> mm,
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obj<AAllocator> error_mm,
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obj<AGCObject> * p_output) const noexcept
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{
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scope log(XO_DEBUG(true));
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(void)error_mm;
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bool ok = true;
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// stats, indexed by tseq
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// could use c++ vector in scratch space instead of running on
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// boxed types.
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//
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DArray * stats_v = DArray::empty(mm, object_types_.size());
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if (!stats_v)
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return false;
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stats_v->resize(stats_v->capacity());
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log && log(xtag("object_types_.size", object_types_.size()),
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xtag("stats_v.capacity", stats_v->capacity()),
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xtag("stats_v.size", stats_v->size()));
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// count #of occupied type slots
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std::uint32_t n_tseq_present = 0;
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// largest tseq present with non-null AGCObject* iface
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std::int32_t max_tseq = 0;
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for (const ObjectTypeSlot & slot : object_types_) {
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AGCObject * iface = slot.iface();
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if (iface) {
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typeseq tseq = iface->_typeseq();
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++n_tseq_present;
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if (max_tseq < tseq.seqno())
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max_tseq = tseq.seqno();
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assert(tseq.seqno() >= 0);
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auto tname_sv = TypeRegistry::id2name(tseq);
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DString * tname = DString::from_view(mm, tname_sv);
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DDictionary * recd = DDictionary::make(mm);
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if (!recd)
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return false;
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recd->upsert_cstr(mm, "name", obj<AGCObject,DString>(tname));
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recd->upsert_cstr(mm, "tseq", DInteger::box(mm, tseq.seqno()));
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recd->upsert_cstr(mm, "n-live", DInteger::box(mm, 0));
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recd->upsert_cstr(mm, "bytes", DInteger::box(mm, 0));
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stats_v->assign_at(tseq.seqno(), obj<AGCObject,DDictionary>(recd));
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}
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}
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// scan to-space, count objects by type
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for (Generation g{0}; g < config_.n_generation_; ++g) {
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const DArena * arena = this->get_space(Role::to_space(), g);
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for (AllocInfo info : *arena) {
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if (info.is_forwarding_tseq()) {
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assert(false);
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return false;
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}
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uint32_t ix = info.tseq();
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size_t z = info.size();
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auto recd = obj<AGCObject,DDictionary>::from(stats_v->at(ix));
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assert(recd);
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auto n_live_opt = recd->lookup_cstr("n-live");
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assert(n_live_opt);
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auto bytes_opt = recd->lookup_cstr("bytes");
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assert(bytes_opt);
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if (n_live_opt && bytes_opt) {
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auto n_live_gco = obj<AGCObject,DInteger>::from(n_live_opt.value());
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auto bytes_gco = obj<AGCObject,DInteger>::from(bytes_opt.value());
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n_live_gco->assign_value(n_live_gco->value() + 1);
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bytes_gco->assign_value(bytes_gco->value() + z);
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}
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}
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}
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stats_v->resize(max_tseq + 1);
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DArray * final_stats_v = DArray::empty(mm, n_tseq_present);
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for (std::size_t i = 0, n = stats_v->size(); i < n; ++i) {
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auto recd = stats_v->at(i);
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if (recd) {
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bool ok = final_stats_v->push_back(recd);
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assert(ok);
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}
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}
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*p_output = obj<AGCObject,DArray>(final_stats_v);
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return ok;
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}
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bool
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GCObjectStore::report_object_ages(obj<AAllocator> mm,
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obj<AAllocator> error_mm,
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obj<AGCObject> * p_output) const noexcept
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{
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scope log(XO_DEBUG(true));
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(void)error_mm;
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std::uint32_t hard_n_age = config_.arena_config_.header_.max_age() + 1;
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// maximum age of a still-existing object
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std::uint32_t soft_max_age = 0;
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// first pass, establish max age
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for (Generation g{0}; g < config_.n_generation_; ++g) {
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const DArena * arena = this->get_space(Role::to_space(), g);
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for (AllocInfo info : *arena) {
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if (info.is_forwarding_tseq()) {
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assert(false);
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return false;
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}
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uint32_t age = info.age();
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assert(age < hard_n_age);
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soft_max_age = std::max(soft_max_age, age);
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}
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}
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// stats, indexed by age
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DArray * stats_v = DArray::empty(mm, soft_max_age + 1);
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if (!stats_v)
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return false;
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for (std::uint32_t a = 0; a <= soft_max_age; ++a) {
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DDictionary * recd = DDictionary::make(mm);
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if (!recd)
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return false;
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recd->upsert_cstr(mm, "age", DInteger::box(mm, a));
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recd->upsert_cstr(mm, "n-live", DInteger::box(mm, 0));
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recd->upsert_cstr(mm, "bytes", DInteger::box(mm, 0));
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stats_v->push_back(obj<AGCObject,DDictionary>(recd));
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}
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log && log(xtag("soft_max_age", soft_max_age),
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xtag("stats_v.size", stats_v->size()));
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// second pass, populate
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// scan to-space, count objects by age
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//
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for (Generation g{0}; g < config_.n_generation_; ++g) {
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const DArena * arena = this->get_space(Role::to_space(), g);
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for (AllocInfo info : *arena) {
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if (info.is_forwarding_tseq()) {
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assert(false);
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return false;
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}
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uint32_t age = info.age();
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size_t z = info.size();
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auto recd = obj<AGCObject,DDictionary>::from(stats_v->at(age));
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assert(recd);
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auto n_live_opt = recd->lookup_cstr("n-live");
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assert(n_live_opt);
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auto bytes_opt = recd->lookup_cstr("bytes");
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assert(bytes_opt);
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if (n_live_opt && bytes_opt) {
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auto n_live_gco = obj<AGCObject,DInteger>::from(n_live_opt.value());
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auto bytes_gco = obj<AGCObject,DInteger>::from(bytes_opt.value());
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n_live_gco->assign_value(n_live_gco->value() + 1);
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bytes_gco->assign_value(bytes_gco->value() + z);
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}
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}
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}
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*p_output = obj<AGCObject,DArray>(stats_v);
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return true;
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}
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bool
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GCObjectStore::_check_move_policy(header_type alloc_hdr,
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void * object_data,
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Generation upto) const noexcept
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{
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(void)object_data;
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// when gc is moving objects, to- and from- spaces have been
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// reversed: forwarding pointers are located in from-space and
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// refer to to-space.
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object_age age = this->header2age(alloc_hdr);
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Generation g = config_.age2gen(age);
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//assert(runstate_.is_running());
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return (g < upto);
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}
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void
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GCObjectStore::visit_child_aux(VisitReason reason,
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AGCObject * lhs_iface,
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void ** lhs_data,
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Generation upto)
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{
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switch (reason.code()) {
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case VisitReason::code::forward:
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{
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DGCObjectStoreVisitor gcos_visitor(this, upto);
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auto gcos_visitor_obj
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= obj<AGCObjectVisitor,DGCObjectStoreVisitor>(&gcos_visitor);
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// called during collection phase
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this->forward_inplace_aux
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(gcos_visitor_obj, lhs_iface, lhs_data, upto);
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break;
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}
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case VisitReason::code::verify:
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// called during verify_ok
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this->verify_aux(lhs_iface, *lhs_data);
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break;
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default:
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// should be unreachable
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assert(false);
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}
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}
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void
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GCObjectStore::forward_inplace_aux(obj<AGCObjectVisitor> gc,
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AGCObject * lhs_iface,
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void ** lhs_data,
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Generation upto)
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{
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// upto == runstate_.gc_upto()
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scope log(XO_DEBUG(config_.debug_flag_),
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xtag("lhs_data", lhs_data),
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xtag("*lhs_data", lhs_data ? *lhs_data : nullptr));
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/* coordinates with _deep_move() */
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/*
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* lhs obj<AGCObject>
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* | +---------+ +---+-+----+
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* \--->| .iface | | T |G|size| header
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* +---------+ object_data +---+-+----+
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* | .data x----------------->| alloc |
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* +---------+ | data |
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* | for |
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* | instance |
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* | ... |
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* +----------+
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*/
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void * object_data = (std::byte *)*lhs_data;
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if (!object_data) {
|
|
/* trivial to forward nullptr */
|
|
return;
|
|
} else if (!this->contains(Role::from_space(), object_data)) {
|
|
/* *lhs_data either:
|
|
* 1. already in to-space
|
|
* 2. not in GC-allocated space at all
|
|
* (small number of niche examples of this)
|
|
*
|
|
* It's important we recognize case (2) up front.
|
|
* Since not allocated from GC, they don't have
|
|
* an alloc-header.
|
|
*/
|
|
log && log("disposition: not in from-space. Don't forward, but check children");
|
|
|
|
obj<AGCObject> gco(lhs_iface, object_data);
|
|
gco.visit_gco_children(VisitReason::forward(), gc);
|
|
|
|
return;
|
|
}
|
|
|
|
log && log("disposition: in from-space");
|
|
|
|
/** NOTE: for form's sake:
|
|
* lookup actual arena that
|
|
* allocated object data.
|
|
* Only using this to get alloc header
|
|
**/
|
|
DArena * some_arena = this->from_space(Generation(0));
|
|
|
|
DArena::header_type * p_header
|
|
= some_arena->obj2hdr(object_data);
|
|
|
|
DArena::header_type alloc_hdr = *p_header;
|
|
|
|
/* recover allocation size */
|
|
std::size_t alloc_z = some_arena->config_.header_.size_with_padding(alloc_hdr);
|
|
|
|
if (log) {
|
|
log(xtag("some_arena.lo", some_arena->lo_),
|
|
xtag("p_header", p_header),
|
|
xtag("alloc_z", alloc_z));
|
|
|
|
AllocInfo info = this->alloc_info((std::byte *)object_data);
|
|
log(xtag("tseq", info.tseq()),
|
|
xtag("tname", TypeRegistry::id2name(typeseq(info.tseq()))),
|
|
xtag("is_forwarding_tseq", info.is_forwarding_tseq()),
|
|
xtag("age", info.age()),
|
|
xtag("size", info.size()));
|
|
}
|
|
|
|
/* need to be able to fit forwarding pointer
|
|
* in place of forwarded object.
|
|
*
|
|
* This is guaranteed anyway, by alignment rules
|
|
*/
|
|
if (alloc_z < sizeof(uintptr_t)) {
|
|
assert(false);
|
|
}
|
|
|
|
if (this->is_forwarding_header(alloc_hdr)) {
|
|
/* *lhs_data already refers to a forwarding pointer */
|
|
|
|
/*
|
|
* lhs obj<AGCObject> (from-space)
|
|
* | +---------+ +---+-+----+
|
|
* \--->| .iface | |FWD|G|size| alloc_hdr
|
|
* +---------+ object_data +---+-+----+
|
|
* | .data x----------------->| x--------\
|
|
* +---------+ | | | dest
|
|
* | | |
|
|
* +----------+ |
|
|
* |
|
|
* (to-space) |
|
|
* +---+-+----+ |
|
|
* |TSQ|G|size| |
|
|
* +---+-+----+ |
|
|
* | | <-/
|
|
* | |
|
|
* | |
|
|
* +----------+
|
|
*/
|
|
void * dest = *(void**)object_data;
|
|
|
|
*lhs_data = dest;
|
|
/*
|
|
* lhs obj<AGCObject>
|
|
* | +---------+
|
|
* \--->| .iface |
|
|
* +---------+
|
|
* | .data x------------\
|
|
* +---------+ |
|
|
* | dest
|
|
* |
|
|
* |
|
|
* | (to-space)
|
|
* | +---+-+----+
|
|
* | |TSQ|G|size|
|
|
* | +---+-+----+
|
|
* \---> | |
|
|
* | |
|
|
* | |
|
|
* +----------+
|
|
*/
|
|
|
|
if (log) {
|
|
log("lhs_data already forwarded", xtag("dest", dest));
|
|
|
|
AllocInfo info = this->alloc_info((std::byte *)dest);
|
|
log(xtag("tseq", info.tseq()),
|
|
xtag("tname", TypeRegistry::id2name(typeseq(info.tseq()))),
|
|
xtag("age", info.age()), xtag("size", info.size()));
|
|
}
|
|
} else if (this->_check_move_policy(alloc_hdr, object_data, upto)) {
|
|
/* copy object *lhs + replace with forwarding pointer */
|
|
|
|
log && log("forward object now");
|
|
|
|
/*
|
|
* lhs obj<AGCObject> (from-space)
|
|
* | +---------+ +---+-+----+
|
|
* \--->| .iface | |TSQ|G|size| alloc_hdr
|
|
* +---------+ object_data +---+-+----+
|
|
* | .data x----------------> | |
|
|
* +---------+ | |
|
|
* | |
|
|
* +----------+
|
|
*/
|
|
|
|
*lhs_data = this->_shallow_move(gc, lhs_iface, *lhs_data);
|
|
|
|
/*
|
|
* lhs obj<AGCObject> (from-space)
|
|
* | +---------+ +---+-+----+
|
|
* \--->| .iface | |FWD|G|SIZE|
|
|
* +---------+ +---+-+----+
|
|
* | .data x------------\ | x--------\
|
|
* +---------+ | | | |
|
|
* | | | |
|
|
* dest | +----------+ |
|
|
* | |
|
|
* | (to-space) |
|
|
* | +---+-+----+ |
|
|
* | |TSQ|G|size| |
|
|
* | +---+-+----+ |
|
|
* \---> | | <-/
|
|
* | |
|
|
* | |
|
|
* +----------+
|
|
*/
|
|
} else {
|
|
log && log("object not eligible/required to forward");
|
|
|
|
/* object doesn't need to move.
|
|
* e.g. incremental collection + object is tenured
|
|
*/
|
|
}
|
|
} /*_forward_inplace_aux*/
|
|
|
|
void
|
|
GCObjectStore::verify_aux(AGCObject * iface,
|
|
void * data)
|
|
{
|
|
scope log(XO_DEBUG(config_.debug_flag_));
|
|
|
|
(void)iface;
|
|
|
|
Generation g1 = this->generation_of(Role::to_space(), data);
|
|
|
|
if (g1.is_sentinel()) {
|
|
assert(this->contains(Role::to_space(), data) == false);
|
|
|
|
Generation g2 = this->generation_of(Role::from_space(), data);
|
|
|
|
if (!g2.is_sentinel()) {
|
|
// verify failure - live pointer still refers to from-space
|
|
|
|
print_backtrace_dwarf(true /*demangle*/);
|
|
|
|
++(p_verify_stats_->n_from_);
|
|
} else {
|
|
++(p_verify_stats_->n_ext_);
|
|
}
|
|
} else {
|
|
assert(this->contains(Role::to_space(), data));
|
|
|
|
++(p_verify_stats_->n_to_);
|
|
}
|
|
}
|
|
|
|
void
|
|
GCObjectStore::swap_roles(Generation upto) noexcept
|
|
{
|
|
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));
|
|
|
|
std::swap(space_[Role::to_space()][g], space_[Role::from_space()][g]);
|
|
}
|
|
}
|
|
|
|
void
|
|
GCObjectStore::cleanup_phase(Generation upto,
|
|
bool sanitize_flag)
|
|
{
|
|
scope log(XO_DEBUG(config_.debug_flag_), xtag("upto", upto));
|
|
|
|
// everything live has been copied out of from-space
|
|
// -> now set to empty
|
|
//
|
|
for (Generation g = Generation{0}; g < upto; ++g) {
|
|
if (sanitize_flag) {
|
|
space_[Role::from_space()][g]->scrub();
|
|
}
|
|
|
|
space_[Role::from_space()][g]->clear();
|
|
}
|
|
}
|
|
|
|
auto
|
|
GCObjectStore::snap_move_checkpoint(Generation upto) -> GCMoveCheckpoint
|
|
{
|
|
GCMoveCheckpoint gray_lo_v;
|
|
|
|
for (uint32_t g = 0; g < upto; ++g) {
|
|
gray_lo_v[g] = this->to_space(Generation{g})->free_;
|
|
}
|
|
|
|
return gray_lo_v;
|
|
}
|
|
|
|
void
|
|
GCObjectStore::verify_ok() noexcept
|
|
{
|
|
Generation unused_gen;
|
|
DGCObjectStoreVisitor visitor{this, unused_gen};
|
|
|
|
for (Generation g(0); g < config_.n_generation_; ++g) {
|
|
const DArena * space = this->get_space(Role::to_space(), g);
|
|
|
|
for (const AllocInfo & info : *space) {
|
|
|
|
if (info.is_forwarding_tseq()) {
|
|
++(p_verify_stats_->n_fwd_);
|
|
|
|
} else {
|
|
typeseq tseq(info.tseq());
|
|
|
|
const AGCObject * iface = this->lookup_type(tseq);
|
|
|
|
if (iface && !(iface->_has_null_vptr())) {
|
|
const void * data = info.payload().first;
|
|
|
|
// assembled fop for gc-aware object
|
|
obj<AGCObject> gco(iface, const_cast<void *>(data));
|
|
|
|
gco.visit_gco_children(VisitReason::verify(), visitor.ref());
|
|
} else {
|
|
++(p_verify_stats_->n_no_iface_);
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* editor bait: register_type */
|
|
bool
|
|
GCObjectStore::install_type(const AGCObject & meta) noexcept
|
|
{
|
|
scope log(XO_DEBUG(config_.debug_flag_),
|
|
xtag("tseq", meta._typeseq()));
|
|
|
|
typeseq tseq = meta._typeseq();
|
|
|
|
assert(tseq.seqno() > 0);
|
|
|
|
auto ix = static_cast<ObjectTypeTable::size_type>(tseq.seqno());
|
|
|
|
if (ix >= object_types_.size()) {
|
|
if (!object_types_.resize(std::max(2 * object_types_.size(), ix + 1))) {
|
|
log && log("could not increase object_types_ size");
|
|
|
|
return false;
|
|
}
|
|
}
|
|
|
|
assert(ix < object_types_.size());
|
|
|
|
ObjectTypeSlot & slot = object_types_[ix];
|
|
|
|
slot.store_iface(&meta);
|
|
|
|
return true;
|
|
}
|
|
|
|
void *
|
|
GCObjectStore::deep_move_root(const AGCObject * root_iface,
|
|
void ** root_data,
|
|
Generation upto)
|
|
{
|
|
// NOTE:
|
|
// Some roots are non-gc-owned nodes.
|
|
// GC must still visit immediate children of these nodes
|
|
// to move gc-owned children.
|
|
// This implements virtual root node feature,
|
|
// intended to mitigate mutation log churn.
|
|
|
|
scope log(XO_DEBUG(config_.debug_flag_));
|
|
|
|
if (!root_data || !*root_data)
|
|
return nullptr;
|
|
|
|
bool src_in_from_space = this->contains(Role::from_space(), *root_data);
|
|
|
|
DGCObjectStoreVisitor visitor(this, upto);
|
|
|
|
if (src_in_from_space) {
|
|
*root_data = this->_deep_move_gc_owned(visitor.ref(), *root_data, upto);
|
|
} else {
|
|
// we aren't moving from_src, it's not gc-owned.
|
|
// However we are moving all its gc-owned children
|
|
|
|
GCMoveCheckpoint gray_lo_v
|
|
= this->snap_move_checkpoint(upto);
|
|
|
|
auto root = obj<AGCObject>(root_iface, *root_data);
|
|
|
|
root.visit_gco_children(VisitReason::forward(), visitor.ref());
|
|
|
|
// For each generation g:
|
|
// traverse objects newer than gray_lo_v[g], to make sure children
|
|
// are forwarded. Fixpoint reached when gray_lo_v[g] doesn't change.
|
|
// Remember that forwarding may promote objects to older generation,
|
|
// so need multiple passes
|
|
//
|
|
this->_forward_children_until_fixpoint(visitor.ref(), upto, gray_lo_v);
|
|
|
|
// reminder: *root_data preserved
|
|
|
|
}
|
|
|
|
return *root_data;
|
|
}
|
|
|
|
void *
|
|
GCObjectStore::deep_move_interior(obj<AGCObjectVisitor> gc,
|
|
void * from_src,
|
|
Generation upto)
|
|
{
|
|
scope log(XO_DEBUG(config_.debug_flag_));
|
|
|
|
if (!from_src)
|
|
return nullptr;
|
|
|
|
bool src_in_from_space = this->contains(Role::from_space(), from_src);
|
|
|
|
if (!src_in_from_space)
|
|
return from_src;
|
|
|
|
return this->_deep_move_gc_owned(gc, from_src, upto);
|
|
}
|
|
|
|
void *
|
|
GCObjectStore::_deep_move_gc_owned(obj<AGCObjectVisitor> gc,
|
|
void * from_src,
|
|
Generation upto)
|
|
{
|
|
scope log(XO_DEBUG(config_.debug_flag_));
|
|
|
|
AllocInfo info = this->alloc_info((std::byte *)from_src);
|
|
AllocHeader hdr = info.header();
|
|
typeseq tseq(info.tseq());
|
|
|
|
assert(this->contains_allocated(Role::from_space(), from_src));
|
|
|
|
if (this->is_forwarding_header(hdr)) {
|
|
/* already forwarded - pickup destination
|
|
*
|
|
* Coordinates with forward_inplace()
|
|
*/
|
|
log && log("disposition: already forwarded");
|
|
|
|
return *(void **)from_src;
|
|
}
|
|
|
|
/* here: object at from_src not already forwarded */
|
|
|
|
if (!this->_check_move_policy(hdr, from_src, upto)) {
|
|
/* object at from_src is in generation that is not being collected */
|
|
log && log("disposition: not moving from_src");
|
|
|
|
return from_src;
|
|
}
|
|
|
|
log && log("disposition: move subtree");
|
|
|
|
/* TODO: AllocIterator pointing to free pointer */
|
|
GCMoveCheckpoint gray_lo_v = this->snap_move_checkpoint(upto);
|
|
|
|
AGCObject * iface = this->lookup_type(tseq);
|
|
|
|
//assert(iface && (iface->_has_null_vptr() == false));
|
|
|
|
void * to_dest = nullptr;
|
|
|
|
if (iface) [[likely]] {
|
|
to_dest = this->_shallow_move(gc, iface, from_src);
|
|
|
|
this->_forward_children_until_fixpoint(gc, upto, gray_lo_v);
|
|
|
|
log && log(xtag("to_dest", to_dest));
|
|
}
|
|
|
|
return to_dest;
|
|
} /*_deep_move_gc_owned*/
|
|
|
|
void *
|
|
GCObjectStore::_shallow_move(obj<AGCObjectVisitor> gc,
|
|
AGCObject * iface,
|
|
void * from_src)
|
|
{
|
|
scope log(XO_DEBUG(config_.debug_flag_));
|
|
|
|
AllocInfo info = this->alloc_info((std::byte *)from_src);
|
|
|
|
void * to_dest = iface->gco_shallow_move(from_src, gc);
|
|
|
|
log && log(xtag("from_src", from_src), xtag("to_dest", to_dest));
|
|
log && log(xtag("tseq", info.tseq()),
|
|
xtag("tname", TypeRegistry::id2name(typeseq(info.tseq()))),
|
|
xtag("age", info.age()),
|
|
xtag("size", info.size()));
|
|
|
|
if (config_.debug_flag_) {
|
|
AllocInfo info_copy = this->alloc_info((std::byte *)to_dest);
|
|
|
|
log && log(xtag("age2", info_copy.age()), xtag("size2", info_copy.size()));
|
|
|
|
assert((info_copy.age() == config_.arena_config_.header_.max_age())
|
|
|| (info_copy.age() == info.age() + 1));
|
|
}
|
|
|
|
if(to_dest == from_src) {
|
|
assert(false);
|
|
} else {
|
|
*(const_cast<AllocHeader*>(info.p_header_))
|
|
= AllocHeader(config_
|
|
.arena_config_
|
|
.header_
|
|
.mark_forwarding_tseq(*info.p_header_));
|
|
|
|
*(void **)from_src = to_dest;
|
|
}
|
|
|
|
return to_dest;
|
|
} /*_shallow_move*/
|
|
|
|
void
|
|
GCObjectStore::_forward_children_until_fixpoint(obj<AGCObjectVisitor> gc,
|
|
Generation upto,
|
|
GCMoveCheckpoint gray_lo_v)
|
|
{
|
|
scope log(XO_DEBUG(config_.debug_flag_));
|
|
|
|
/**
|
|
* To-space:
|
|
*
|
|
* to_lo = start of to-space
|
|
* w,W = white objects. An object x is white if x
|
|
* + all immediate children of x are in to-space
|
|
* (also implies this GC cycle put it there)
|
|
* g,G = grey objects. An object x is gray if it's in to-space,
|
|
* but possibly has >0 black children
|
|
* _ = free to-space memory
|
|
* N = nursery space (generation{0})
|
|
* T = tenured space (generation{1})
|
|
*
|
|
* wwwwwwwwwwwwwwwwwwwggggggggggggggggggggg_________________...
|
|
* ^ ^ ^
|
|
* to_lo grey_lo(N) free_ptr(N)
|
|
*
|
|
* After moving children of one object,
|
|
* advancing {nursery_grey_lo, nursery_free_ptr}
|
|
*
|
|
* wwwwwwwwwwwwwwwwwwwWWWWgggggggggggggggggGGGGGGGGGGG______...
|
|
* ^ ^ ^
|
|
* to_lo grey_lo(N) free_ptr(N)
|
|
*
|
|
* Invariant:
|
|
*
|
|
* objects in [to_lo, gray_lo) are white.
|
|
* all gray objects are in [gray_lo, free_ptr)
|
|
* memory starting at free_ptr is free.
|
|
*
|
|
* deep_move terminates when gray_lo catches up to free_ptr
|
|
*
|
|
* Above is simplified. Complication is that GC (including incremental) may
|
|
* promote objects from nursery (N) to tenured (T)
|
|
*
|
|
* So more accurate before/after picture
|
|
*
|
|
* N wwwwwwwwwwwwwwwwwwwggggggggggggggggggggg_________________...
|
|
* ^ ^ ^
|
|
* to_lo(N) grey_lo(N) free_ptr(N)
|
|
*
|
|
* T wwwwwwwwwwwwwwgggggggggggg_______________________________...
|
|
* ^ ^ ^
|
|
* to_lo(T) grey_lo(T) free_ptr(N)
|
|
*
|
|
* After moving children of one object,
|
|
* advancing {nursery_grey_lo, nursery_free_ptr}
|
|
*
|
|
* N wwwwwwwwwwwwwwwwwwwWWWWgggggggggggggggggGGGGGGGGGGG_____...
|
|
* ^ ^ ^
|
|
* to_lo(N) grey_lo(N) free_ptr(N)
|
|
*
|
|
* T wwwwwwwwwwwwwwggggggggggggGGGGG_________________________...
|
|
* ^ ^ ^
|
|
* to_lo(T) grey_lo(T) free_ptr(T)
|
|
*
|
|
* deep_move terminates when both:
|
|
* - gray_lo(N) catches up with free_ptr(N)
|
|
* - gray_lo(T) catches up with free_ptr(T)
|
|
*
|
|
**/
|
|
|
|
std::size_t fixup_work = 0;
|
|
|
|
/* TODO:
|
|
* - loop here is bad for memory locality
|
|
* - replace with depth-first traversal
|
|
*/
|
|
do {
|
|
fixup_work = 0;
|
|
|
|
for (Generation g = Generation{0}; g < upto; ++g) {
|
|
/** object index for this pass **/
|
|
size_t i_obj = 0;
|
|
|
|
/* TODO: use AllocIterator here */
|
|
while(gray_lo_v[g] < to_space(g)->free_) {
|
|
AllocHeader * hdr = (AllocHeader *)gray_lo_v[g];
|
|
void * src = (hdr + 1);
|
|
|
|
const auto & hdr_cfg = config_.arena_config_.header_;
|
|
typeseq tseq = typeseq(hdr_cfg.tseq(*hdr));
|
|
size_t z = hdr_cfg.size_with_padding(*hdr);
|
|
|
|
log && log("deep_move_gc_owned: fwd to-space children",
|
|
xtag("g", g),
|
|
xtag("i_obj", i_obj),
|
|
xtag("src", src),
|
|
xtag("tseq", tseq),
|
|
xtag("tname", TypeRegistry::id2name(tseq)),
|
|
xtag("z", z));
|
|
|
|
const AGCObject * iface = this->lookup_type(tseq);
|
|
|
|
assert(iface->_has_null_vptr() == false);
|
|
|
|
iface->visit_gco_children(src, VisitReason::forward(), gc);
|
|
|
|
gray_lo_v[g] = ((std::byte *)src) + z;
|
|
|
|
++i_obj;
|
|
++fixup_work;
|
|
}
|
|
}
|
|
} while (fixup_work > 0);
|
|
} /*_forward_children_until_fixpoint*/
|
|
|
|
} /*namespace mm*/
|
|
} /*namespace xo*/
|
|
|
|
/* end GCObjectStore.cpp */
|