dcd79af8ed
Most of the lsa gory details are hidden in utils/logalloc.cc. That includes the actual implementation of a lsa region: region_impl. However, there is code in the hot path that often accesses the _reclaiming_enabled member as well as its base class allocation_strategy. In order to optimise those accesses another class is introduced: basic_region_impl that inherits from allocation_strategy and is a base of region_impl. It is defined in utils/logalloc.hh so that it is publicly visible and its member functions are inlineable from anywhere in the code. This class is supposed to be as small as possible, but contain all members and functions that are accessed from the fast path and should be inlined.
2222 lines
74 KiB
C++
2222 lines
74 KiB
C++
/*
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* Copyright (C) 2015 ScyllaDB
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*/
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/*
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* This file is part of Scylla.
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*
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* Scylla is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Scylla is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <boost/range/algorithm/heap_algorithm.hpp>
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#include <boost/range/algorithm/remove.hpp>
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#include <boost/range/algorithm.hpp>
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#include <boost/heap/binomial_heap.hpp>
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#include <boost/intrusive/list.hpp>
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#include <boost/intrusive/set.hpp>
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#include <boost/intrusive/slist.hpp>
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#include <boost/range/adaptors.hpp>
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#include <stack>
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#include <seastar/core/memory.hh>
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#include <seastar/core/align.hh>
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#include <seastar/core/print.hh>
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#include <seastar/core/metrics.hh>
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#include <seastar/util/alloc_failure_injector.hh>
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#include "utils/logalloc.hh"
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#include "log.hh"
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#include "utils/dynamic_bitset.hh"
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#include "utils/log_heap.hh"
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namespace bi = boost::intrusive;
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standard_allocation_strategy standard_allocation_strategy_instance;
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static
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std::vector<const migrate_fn_type*>&
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static_migrators() {
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static std::vector<const migrate_fn_type*> obj;
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return obj;
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}
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namespace debug {
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std::vector<const migrate_fn_type*>* static_migrators = &::static_migrators();
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}
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uint32_t
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migrate_fn_type::register_migrator(const migrate_fn_type* m) {
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static_migrators().push_back(m);
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return static_migrators().size() - 1;
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}
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void
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migrate_fn_type::unregister_migrator(uint32_t index) {
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static_migrators()[index] = nullptr;
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// reuse freed slots? no need now
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}
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namespace logalloc {
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struct segment;
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static logging::logger llogger("lsa");
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static logging::logger timing_logger("lsa-timing");
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static thread_local tracker tracker_instance;
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using clock = std::chrono::steady_clock;
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class tracker::impl {
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std::vector<region::impl*> _regions;
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seastar::metrics::metric_groups _metrics;
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bool _reclaiming_enabled = true;
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size_t _reclamation_step = 1;
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bool _abort_on_bad_alloc = false;
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private:
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// Prevents tracker's reclaimer from running while live. Reclaimer may be
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// invoked synchronously with allocator. This guard ensures that this
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// object is not re-entered while inside one of the tracker's methods.
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struct reclaiming_lock {
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impl& _ref;
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bool _prev;
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reclaiming_lock(impl& ref)
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: _ref(ref)
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, _prev(ref._reclaiming_enabled)
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{
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_ref._reclaiming_enabled = false;
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}
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~reclaiming_lock() {
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_ref._reclaiming_enabled = _prev;
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}
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};
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friend class tracker_reclaimer_lock;
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public:
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impl();
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~impl();
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void register_region(region::impl*);
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void unregister_region(region::impl*);
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size_t reclaim(size_t bytes);
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reactor::idle_cpu_handler_result compact_on_idle(reactor::work_waiting_on_reactor check_for_work);
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size_t compact_and_evict(size_t bytes);
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size_t compact_and_evict_locked(size_t bytes);
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void full_compaction();
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void reclaim_all_free_segments();
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occupancy_stats region_occupancy();
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occupancy_stats occupancy();
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size_t non_lsa_used_space();
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void set_reclamation_step(size_t step_in_segments) { _reclamation_step = step_in_segments; }
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size_t reclamation_step() const { return _reclamation_step; }
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void enable_abort_on_bad_alloc() { _abort_on_bad_alloc = true; }
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bool should_abort_on_bad_alloc() const { return _abort_on_bad_alloc; }
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};
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class tracker_reclaimer_lock {
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tracker::impl::reclaiming_lock _lock;
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public:
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tracker_reclaimer_lock() : _lock(shard_tracker().get_impl()) { }
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};
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tracker::tracker()
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: _impl(std::make_unique<impl>())
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, _reclaimer([this] { return reclaim(); }, memory::reclaimer_scope::sync)
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{ }
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tracker::~tracker() {
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}
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size_t tracker::reclaim(size_t bytes) {
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return _impl->reclaim(bytes);
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}
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reactor::idle_cpu_handler_result tracker::compact_on_idle(reactor::work_waiting_on_reactor check_for_work) {
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return _impl->compact_on_idle(check_for_work);
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}
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occupancy_stats tracker::region_occupancy() {
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return _impl->region_occupancy();
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}
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occupancy_stats tracker::occupancy() {
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return _impl->occupancy();
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}
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size_t tracker::non_lsa_used_space() const {
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return _impl->non_lsa_used_space();
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}
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void tracker::full_compaction() {
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return _impl->full_compaction();
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}
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void tracker::reclaim_all_free_segments() {
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return _impl->reclaim_all_free_segments();
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}
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tracker& shard_tracker() {
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return tracker_instance;
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}
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struct segment {
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static constexpr int size_shift = segment_size_shift;
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using size_type = std::conditional_t<(size_shift < 16), uint16_t, uint32_t>;
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static constexpr size_t size = segment_size;
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uint8_t data[size];
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segment() noexcept { }
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template<typename T = void>
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const T* at(size_t offset) const {
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return reinterpret_cast<const T*>(data + offset);
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}
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template<typename T = void>
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T* at(size_t offset) {
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return reinterpret_cast<T*>(data + offset);
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}
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bool is_empty() const;
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void record_alloc(size_type size);
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void record_free(size_type size);
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occupancy_stats occupancy() const;
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#ifndef DEFAULT_ALLOCATOR
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static void* operator new(size_t size) = delete;
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static void* operator new(size_t, void* ptr) noexcept { return ptr; }
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static void operator delete(void* ptr) = delete;
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#endif
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};
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class segment_zone;
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static constexpr size_t max_managed_object_size = segment_size * 0.1;
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static constexpr size_t max_used_space_for_compaction = segment_size * 0.85;
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static constexpr size_t min_free_space_for_compaction = segment_size - max_used_space_for_compaction;
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static_assert(min_free_space_for_compaction >= max_managed_object_size,
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"Segments which cannot fit max_managed_object_size must not be considered compactible for the sake of forward progress of compaction");
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// Since we only compact if there's >= min_free_space_for_compaction of free space,
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// we use min_free_space_for_compaction as the histogram's minimum size and put
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// everything below that value in the same bucket.
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extern constexpr log_heap_options segment_descriptor_hist_options(min_free_space_for_compaction, 3, segment_size);
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struct segment_descriptor : public log_heap_hook<segment_descriptor_hist_options> {
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bool _lsa_managed;
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segment::size_type _free_space;
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region::impl* _region;
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segment_zone* _zone;
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segment_descriptor()
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: _lsa_managed(false), _region(nullptr)
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{ }
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bool is_empty() const {
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return _free_space == segment::size;
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}
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occupancy_stats occupancy() const {
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return { _free_space, segment::size };
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}
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void record_alloc(segment::size_type size) {
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_free_space -= size;
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}
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void record_free(segment::size_type size) {
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_free_space += size;
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}
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};
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using segment_descriptor_hist = log_heap<segment_descriptor, segment_descriptor_hist_options>;
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#ifndef DEFAULT_ALLOCATOR
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struct free_segment : public boost::intrusive::list_base_hook<> {
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} __attribute__((packed));
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class segment_stack {
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boost::intrusive::list<free_segment> _stack;
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public:
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segment* pop() noexcept {
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auto& seg = _stack.front();
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_stack.pop_front();
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seg.~free_segment();
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return reinterpret_cast<segment*>(&seg);
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}
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void push(segment* seg) noexcept {
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free_segment* fs = new (seg) free_segment;
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_stack.push_front(*fs);
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}
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size_t size() const {
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return _stack.size();
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}
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void replace(segment* src, segment* dst) noexcept {
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auto fseg = reinterpret_cast<free_segment*>(src);
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_stack.erase(_stack.iterator_to(*fseg));
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fseg->~free_segment();
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push(dst);
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}
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};
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static inline bool can_allocate_more_memory(size_t size)
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{
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// We want to leave more free memory than just min_free_memory() in order to reduce
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// the frequency of expensive segment-migrating reclaim() called by the seastar allocator.
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static constexpr size_t min_gap = 1 * 1024 * 1024;
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static constexpr size_t max_gap = 64 * 1024 * 1024;
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static const size_t gap = std::min(max_gap, std::max(memory::stats().total_memory() / 16, min_gap));
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return memory::stats().free_memory() > memory::min_free_memory() + size + gap;
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}
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// Segment zone is a contiguous area containing, potentially, a large number
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// of segments. It is used to allocate memory from general-purpose allocator
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// for the LSA use. The goal of having all segments in several big zones is
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// to reduce memory fragmentation caused by the LSA.
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// When general-purpose allocator needs to reclaim some memory from the LSA it
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// is done by:
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// 1) migrating segments between zones in an attempt to remove some of them
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// 2) moving segments inside a zone to its beginning and shrinking that zone
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//
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// Zones can be shrunk but cannot grow.
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class segment_zone : public bi::set_base_hook<>, public bi::slist_base_hook<> {
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struct free_segment : public bi::slist_base_hook<> { };
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static constexpr size_t maximum_size = max_zone_segments;
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static constexpr size_t minimum_size = 16;
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static thread_local size_t next_attempt_size;
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// Bitset of all segments belonging to this zone. Used segments have their
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// corresponding bit clear, free segments - set.
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// FIXME: Add second level bitmap for faster allocation in large zones.
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utils::dynamic_bitset _segments;
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bi::slist<free_segment, bi::constant_time_size<false>> _free_segments;
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size_t _used_segment_count = 0;
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segment* _base;
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private:
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segment* segment_from_position(size_t pos) const {
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return _base + pos;
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}
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size_t position_from_segment(segment* seg) const {
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return seg - _base;
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}
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bool migrate_segment(size_t from, size_t to);
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size_t shrink_by(size_t delta);
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public:
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segment_zone(segment* base, size_t size) : _base(base) {
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_segments.resize(size, true);
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}
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static std::unique_ptr<segment_zone> try_creating_zone();
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~segment_zone() {
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assert(empty());
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if (_segments.size()) {
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free(_base);
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}
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llogger.debug("Removed zone @{}", this);
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}
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segment_zone(const segment_zone&) = delete;
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segment_zone& operator=(const segment_zone&) = delete;
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segment* allocate_segment() {
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assert(!_free_segments.empty());
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auto& fseg = _free_segments.front();
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_free_segments.pop_front();
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fseg.~free_segment();
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auto seg = new (&fseg) segment;
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_used_segment_count++;
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_segments.clear(position_from_segment(seg));
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return seg;
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}
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void deallocate_segment(segment* seg) {
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_segments.set(position_from_segment(seg));
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_used_segment_count--;
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seg->~segment();
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_free_segments.push_front(*new (seg) free_segment);
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}
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// The following two functions invalidate _free_segments list.
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// rebuild_free_segments_list() needs to be called afterwards to restore
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// valid state.
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size_t defragment_and_shrink_by(size_t);
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bool migrate_segments(segment_zone& dst, size_t to_migrate);
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void rebuild_free_segments_list() {
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_free_segments.clear_and_dispose([] (auto fseg) { fseg->~free_segment(); });
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auto pos = _segments.find_last_set();
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while (pos != utils::dynamic_bitset::npos) {
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_free_segments.push_front(*new (segment_from_position(pos)) free_segment);
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pos = _segments.find_previous_set(pos);
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}
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}
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bool empty() const { return !used_segment_count(); }
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size_t segment_count() const { return _segments.size(); }
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size_t used_segment_count() const { return _used_segment_count; }
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size_t free_segment_count() const { return _segments.size() - _used_segment_count; }
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segment* base() const { return _base; }
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};
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thread_local size_t segment_zone::next_attempt_size = segment_zone::maximum_size;
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constexpr size_t segment_zone::minimum_size;
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constexpr size_t segment_zone::maximum_size;
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std::unique_ptr<segment_zone> segment_zone::try_creating_zone()
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{
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std::unique_ptr<segment_zone> zone;
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auto next_size = next_attempt_size;
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while (next_size) {
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auto size = next_size;
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next_size >>= 1;
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if (!can_allocate_more_memory(size << segment::size_shift)) {
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continue;
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}
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memory::disable_abort_on_alloc_failure_temporarily no_abort_guard;
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seastar::memory::scoped_large_allocation_warning_disable slawd;
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auto ptr = aligned_alloc(segment::size, size << segment::size_shift);
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if (!ptr) {
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continue;
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}
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try {
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zone = std::make_unique<segment_zone>(static_cast<segment*>(ptr), size);
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llogger.debug("Creating new zone @{}, size: {}", zone.get(), size);
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next_attempt_size = std::min(std::max(size << 1, minimum_size), maximum_size);
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while (size--) {
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auto seg = zone->segment_from_position(size);
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zone->_free_segments.push_front(*new (seg) free_segment);
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}
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return zone;
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} catch (const std::bad_alloc&) {
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free(ptr);
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}
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}
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llogger.trace("Failed to create zone");
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next_attempt_size = minimum_size;
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return zone;
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}
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struct segment_zone_base_address_compare {
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bool operator()(const segment_zone& a, const segment_zone& b) const noexcept {
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return a.base() < b.base();
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}
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};
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size_t segment_zone::defragment_and_shrink_by(size_t delta)
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{
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_free_segments.clear_and_dispose([] (auto* fseg) { fseg->~free_segment(); });
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delta = std::min(delta, free_segment_count());
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auto new_size = segment_count() - delta;
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auto used_pos = _segments.find_last_clear();
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auto free_pos = _segments.find_first_set();
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while (used_pos >= new_size && used_pos != utils::dynamic_bitset::npos) {
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assert(free_pos < used_pos);
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auto could_compact = migrate_segment(used_pos, free_pos);
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if (!could_compact) {
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delta = segment_count() - used_pos - 1;
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break;
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}
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_segments.set(used_pos);
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_segments.clear(free_pos);
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free_pos = _segments.find_next_set(free_pos);
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used_pos = _segments.find_previous_clear(used_pos);
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}
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return shrink_by(delta);
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}
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size_t segment_zone::shrink_by(size_t delta)
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{
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_free_segments.clear_and_dispose([] (auto* fseg) { fseg->~free_segment(); });
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delta = std::min(delta, free_segment_count());
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auto new_size = segment_count() - delta;
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llogger.debug("Shrinking zone @{} by {} segments (total: {})", this, delta, new_size);
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_segments.resize(new_size);
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// Seastar allocator guarantees that realloc shrinks buffer in place.
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auto ptr = realloc(_base, new_size << segment::size_shift);
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assert(ptr == _base || !ptr);
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return delta;
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}
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// Segment pool implementation for the seastar allocator.
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// Stores segment descriptors in a vector which is indexed using most significant
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// bits of segment address.
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class segment_pool {
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std::vector<segment_descriptor> _segments;
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uintptr_t _segments_base; // The address of the first segment
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size_t _segments_in_use{};
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memory::memory_layout _layout;
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size_t _current_emergency_reserve_goal = 1;
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size_t _emergency_reserve_max = 30;
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segment_stack _emergency_reserve;
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bool _allocation_failure_flag = false;
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size_t _non_lsa_memory_in_use = 0;
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// Tree of all zones ordered by the base address.
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using all_zones_type = bi::set<segment_zone, bi::compare<segment_zone_base_address_compare>>;
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all_zones_type _all_zones;
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bi::slist<segment_zone> _not_full_zones;
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size_t _free_segments_in_zones = 0;
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private:
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segment* allocate_segment();
|
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void deallocate_segment(segment* seg);
|
|
friend void* segment::operator new(size_t);
|
|
friend void segment::operator delete(void*);
|
|
|
|
segment* allocate_or_fallback_to_reserve();
|
|
void free_or_restore_to_reserve(segment* seg) noexcept;
|
|
public:
|
|
segment_pool();
|
|
~segment_pool() {
|
|
while (_emergency_reserve.size()) {
|
|
deallocate_segment(_emergency_reserve.pop());
|
|
}
|
|
}
|
|
segment* new_segment(region::impl* r);
|
|
segment_descriptor& descriptor(const segment*);
|
|
// Returns segment containing given object or nullptr.
|
|
segment* containing_segment(const void* obj) const;
|
|
segment* segment_from(const segment_descriptor& desc);
|
|
void free_segment(segment*) noexcept;
|
|
void free_segment(segment*, segment_descriptor&) noexcept;
|
|
size_t segments_in_use() const;
|
|
size_t current_emergency_reserve_goal() const { return _current_emergency_reserve_goal; }
|
|
void set_emergency_reserve_max(size_t new_size) { _emergency_reserve_max = new_size; }
|
|
size_t emergency_reserve_max() { return _emergency_reserve_max; }
|
|
void set_current_emergency_reserve_goal(size_t goal) { _current_emergency_reserve_goal = goal; }
|
|
void clear_allocation_failure_flag() { _allocation_failure_flag = false; }
|
|
bool allocation_failure_flag() { return _allocation_failure_flag; }
|
|
void refill_emergency_reserve();
|
|
size_t trim_emergency_reserve_to_max();
|
|
void update_non_lsa_memory_in_use(ssize_t n) {
|
|
_non_lsa_memory_in_use += n;
|
|
}
|
|
size_t non_lsa_memory_in_use() const {
|
|
return _non_lsa_memory_in_use;
|
|
}
|
|
size_t total_memory_in_use() const {
|
|
return _non_lsa_memory_in_use + _segments_in_use * segment::size;
|
|
}
|
|
struct reservation_goal;
|
|
void set_region(const segment* seg, region::impl* r) {
|
|
set_region(descriptor(seg), r);
|
|
}
|
|
void set_region(segment_descriptor& desc, region::impl* r) {
|
|
desc._region = r;
|
|
}
|
|
bool migrate_segment(segment* src, segment_zone& src_zone, segment* dst,
|
|
segment_zone& dst_zone);
|
|
size_t reclaim_segments(size_t target);
|
|
void reclaim_all_free_segments() {
|
|
reclaim_segments(std::numeric_limits<size_t>::max());
|
|
}
|
|
|
|
struct stats {
|
|
size_t segments_migrated;
|
|
size_t segments_compacted;
|
|
};
|
|
private:
|
|
stats _stats{};
|
|
public:
|
|
size_t zone_count() const { return _all_zones.size(); }
|
|
const stats& statistics() const { return _stats; }
|
|
void on_segment_migration() { _stats.segments_migrated++; }
|
|
void on_segment_compaction() { _stats.segments_compacted++; }
|
|
size_t free_segments_in_zones() const { return _free_segments_in_zones; }
|
|
size_t free_segments() const { return _free_segments_in_zones + _emergency_reserve.size(); }
|
|
};
|
|
|
|
size_t segment_pool::reclaim_segments(size_t target) {
|
|
// Reclaimer tries to release segments occupying higher parts of the address
|
|
// space. A tree of zones is traversed starting from the zone based at
|
|
// the highest address: segments are migrated to the zones in the lower
|
|
// parts of the address space and the zones are shrunk.
|
|
|
|
if (!_free_segments_in_zones) {
|
|
return 0;
|
|
}
|
|
|
|
llogger.debug("Trying to reclaim {} segments form {} zones ({} full)", target,
|
|
_all_zones.size(), _all_zones.size() - _not_full_zones.size());
|
|
|
|
// Reclamation. Migrate segments to lower addresses and shrink zones.
|
|
size_t reclaimed_segments = 0;
|
|
_not_full_zones.clear();
|
|
for (auto& zone : _all_zones | boost::adaptors::reversed) {
|
|
_free_segments_in_zones -= zone.free_segment_count();
|
|
auto to_reclaim = target - reclaimed_segments;
|
|
if (_free_segments_in_zones && zone.free_segment_count() < to_reclaim) {
|
|
auto end = _all_zones.iterator_to(zone);
|
|
for (auto it = _all_zones.begin(); it != end && zone.free_segment_count() < to_reclaim; ++it) {
|
|
auto could_migrate = zone.migrate_segments(*it, to_reclaim - zone.free_segment_count());
|
|
if (zone.empty() || !could_migrate) {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
reclaimed_segments += zone.defragment_and_shrink_by(to_reclaim);
|
|
if (reclaimed_segments >= target) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Clean up. Rebuild non-full zones list and remove empty zones.
|
|
_free_segments_in_zones = 0;
|
|
bi::slist<segment_zone> zones_to_remove;
|
|
for (auto& zone : _all_zones | boost::adaptors::reversed) {
|
|
if (zone.empty()) {
|
|
reclaimed_segments += zone.free_segment_count();
|
|
zones_to_remove.push_front(zone);
|
|
} else if (zone.free_segment_count()) {
|
|
_free_segments_in_zones += zone.free_segment_count();
|
|
zone.rebuild_free_segments_list();
|
|
_not_full_zones.push_front(zone);
|
|
}
|
|
}
|
|
zones_to_remove.clear_and_dispose([this] (auto zone) {
|
|
_all_zones.erase(_all_zones.iterator_to(*zone));
|
|
delete zone;
|
|
});
|
|
// FIXME: merge adjacent zones to reduce memory footprint of zone metadata
|
|
|
|
llogger.debug("Reclaimed {} segments (requested {}), {} zones left",
|
|
reclaimed_segments, target, _all_zones.size());
|
|
return reclaimed_segments;
|
|
}
|
|
|
|
segment* segment_pool::allocate_segment()
|
|
{
|
|
//
|
|
// When allocating a segment we want to avoid two things:
|
|
// - allocating a new zone could cause other to be shrunk or removed
|
|
// - LSA and general-purpose allocator shouldn't constantly fight each
|
|
// other for every last bit of memory
|
|
//
|
|
// allocate_segment() always works with LSA reclaimer disabled.
|
|
// 1. Firstly, the algorithm tries to allocate segment from one of the
|
|
// already existing zones.
|
|
// 2. If no zone is able to provide a new segment the algorithm tries to
|
|
// create a new one. However, if the free memory is below set threshold
|
|
// this step is skipped.
|
|
// 3. Finally, the algorithm ties to compact and evict data stored in LSA
|
|
// memory in order to reclaim enough segments.
|
|
//
|
|
auto set_zone = [this] (segment* seg, segment_zone& zone) {
|
|
auto& desc = descriptor(seg);
|
|
desc._zone = &zone;
|
|
};
|
|
|
|
do {
|
|
tracker_reclaimer_lock rl;
|
|
if (!_not_full_zones.empty()) {
|
|
auto& zone = _not_full_zones.front();
|
|
auto seg = zone.allocate_segment();
|
|
set_zone(seg, zone);
|
|
_free_segments_in_zones--;
|
|
if (!zone.free_segment_count()) {
|
|
_not_full_zones.pop_front();
|
|
}
|
|
return seg;
|
|
}
|
|
if (can_allocate_more_memory(segment::size)) {
|
|
segment_zone* zone;
|
|
try {
|
|
zone = segment_zone::try_creating_zone().release();
|
|
if (!zone) {
|
|
continue;
|
|
}
|
|
} catch (const std::bad_alloc&) {
|
|
continue;
|
|
}
|
|
auto seg = zone->allocate_segment();
|
|
set_zone(seg, *zone);
|
|
_all_zones.insert(*zone);
|
|
if (zone->free_segment_count()) {
|
|
_free_segments_in_zones += zone->free_segment_count();
|
|
_not_full_zones.push_front(*zone);
|
|
}
|
|
return seg;
|
|
}
|
|
} while (shard_tracker().get_impl().compact_and_evict(shard_tracker().reclamation_step() * segment::size));
|
|
if (shard_tracker().should_abort_on_bad_alloc()) {
|
|
llogger.error("Aborting due to segment allocation failure");
|
|
abort();
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
void segment_pool::deallocate_segment(segment* seg)
|
|
{
|
|
auto& desc = descriptor(seg);
|
|
assert(desc._zone);
|
|
auto zone = desc._zone;
|
|
if (!zone->free_segment_count()) {
|
|
_not_full_zones.push_front(*zone);
|
|
}
|
|
zone->deallocate_segment(seg);
|
|
_free_segments_in_zones++;
|
|
}
|
|
|
|
void segment_pool::refill_emergency_reserve() {
|
|
while (_emergency_reserve.size() < _emergency_reserve_max) {
|
|
auto seg = allocate_segment();
|
|
if (!seg) {
|
|
throw std::bad_alloc();
|
|
}
|
|
_emergency_reserve.push(seg);
|
|
}
|
|
}
|
|
|
|
size_t segment_pool::trim_emergency_reserve_to_max() {
|
|
size_t n_released = 0;
|
|
while (_emergency_reserve.size() > _emergency_reserve_max) {
|
|
deallocate_segment(_emergency_reserve.pop());
|
|
++n_released;
|
|
}
|
|
return n_released;
|
|
}
|
|
|
|
segment_descriptor&
|
|
segment_pool::descriptor(const segment* seg) {
|
|
uintptr_t seg_addr = reinterpret_cast<uintptr_t>(seg);
|
|
uintptr_t index = (seg_addr - _segments_base) >> segment::size_shift;
|
|
return _segments[index];
|
|
}
|
|
|
|
segment*
|
|
segment_pool::containing_segment(const void* obj) const {
|
|
auto addr = reinterpret_cast<uintptr_t>(obj);
|
|
auto offset = addr & (segment::size - 1);
|
|
auto index = (addr - _segments_base) >> segment::size_shift;
|
|
auto& desc = _segments[index];
|
|
if (desc._lsa_managed) {
|
|
return reinterpret_cast<segment*>(addr - offset);
|
|
} else {
|
|
return nullptr;
|
|
}
|
|
}
|
|
|
|
segment*
|
|
segment_pool::segment_from(const segment_descriptor& desc) {
|
|
assert(desc._lsa_managed);
|
|
auto index = &desc - &_segments[0];
|
|
return reinterpret_cast<segment*>(_segments_base + (index << segment::size_shift));
|
|
}
|
|
|
|
segment*
|
|
segment_pool::allocate_or_fallback_to_reserve() {
|
|
if (_emergency_reserve.size() <= _current_emergency_reserve_goal) {
|
|
auto seg = allocate_segment();
|
|
if (!seg) {
|
|
_allocation_failure_flag = true;
|
|
throw std::bad_alloc();
|
|
}
|
|
return seg;
|
|
}
|
|
return _emergency_reserve.pop();
|
|
}
|
|
|
|
void
|
|
segment_pool::free_or_restore_to_reserve(segment* seg) noexcept {
|
|
if (_emergency_reserve.size() < emergency_reserve_max()) {
|
|
_emergency_reserve.push(seg);
|
|
} else {
|
|
deallocate_segment(seg);
|
|
}
|
|
}
|
|
|
|
segment*
|
|
segment_pool::new_segment(region::impl* r) {
|
|
auto seg = allocate_or_fallback_to_reserve();
|
|
++_segments_in_use;
|
|
segment_descriptor& desc = descriptor(seg);
|
|
desc._lsa_managed = true;
|
|
desc._free_space = segment::size;
|
|
desc._region = r;
|
|
return seg;
|
|
}
|
|
|
|
void segment_pool::free_segment(segment* seg) noexcept {
|
|
free_segment(seg, descriptor(seg));
|
|
}
|
|
|
|
void segment_pool::free_segment(segment* seg, segment_descriptor& desc) noexcept {
|
|
llogger.trace("Releasing segment {}", seg);
|
|
desc._lsa_managed = false;
|
|
desc._region = nullptr;
|
|
free_or_restore_to_reserve(seg);
|
|
--_segments_in_use;
|
|
}
|
|
|
|
segment_pool::segment_pool()
|
|
: _layout(memory::get_memory_layout())
|
|
{
|
|
_segments_base = align_down(_layout.start, (uintptr_t)segment::size);
|
|
_segments.resize((_layout.end - _segments_base) / segment::size);
|
|
for (size_t i = 0; i < _current_emergency_reserve_goal; ++i) {
|
|
auto seg = allocate_segment();
|
|
if (!seg) {
|
|
throw std::bad_alloc();
|
|
}
|
|
_emergency_reserve.push(seg);
|
|
}
|
|
}
|
|
|
|
#else
|
|
|
|
// Segment pool version for the standard allocator. Slightly less efficient
|
|
// than the version for seastar's allocator.
|
|
class segment_pool {
|
|
std::unordered_map<const segment*, segment_descriptor> _segments;
|
|
std::unordered_map<const segment_descriptor*, segment*> _segment_descs;
|
|
size_t _segments_in_use{};
|
|
size_t _non_lsa_memory_in_use = 0;
|
|
public:
|
|
segment* new_segment(region::impl* r) {
|
|
++_segments_in_use;
|
|
auto seg = new (with_alignment(segment::size)) segment;
|
|
assert((reinterpret_cast<uintptr_t>(seg) & (sizeof(segment) - 1)) == 0);
|
|
segment_descriptor& desc = _segments[seg];
|
|
desc._lsa_managed = true;
|
|
desc._free_space = segment::size;
|
|
desc._region = r;
|
|
_segment_descs[&desc] = seg;
|
|
return seg;
|
|
}
|
|
segment_descriptor& descriptor(const segment* seg) {
|
|
auto i = _segments.find(seg);
|
|
if (i != _segments.end()) {
|
|
return i->second;
|
|
} else {
|
|
segment_descriptor& desc = _segments[seg];
|
|
desc._lsa_managed = false;
|
|
return desc;
|
|
}
|
|
}
|
|
segment* segment_from(segment_descriptor& desc) {
|
|
auto i = _segment_descs.find(&desc);
|
|
assert(i != _segment_descs.end());
|
|
return i->second;
|
|
}
|
|
void free_segment(segment* seg, segment_descriptor& desc) {
|
|
free_segment(seg);
|
|
}
|
|
void free_segment(segment* seg) {
|
|
--_segments_in_use;
|
|
auto i = _segments.find(seg);
|
|
assert(i != _segments.end());
|
|
_segment_descs.erase(&i->second);
|
|
_segments.erase(i);
|
|
::free(seg);
|
|
}
|
|
segment* containing_segment(const void* obj) const {
|
|
uintptr_t addr = reinterpret_cast<uintptr_t>(obj);
|
|
auto seg = reinterpret_cast<segment*>(align_down(addr, static_cast<uintptr_t>(segment::size)));
|
|
auto i = _segments.find(seg);
|
|
if (i == _segments.end()) {
|
|
return nullptr;
|
|
}
|
|
return seg;
|
|
}
|
|
size_t segments_in_use() const;
|
|
size_t current_emergency_reserve_goal() const { return 0; }
|
|
void set_current_emergency_reserve_goal(size_t goal) { }
|
|
void set_emergency_reserve_max(size_t new_size) { }
|
|
size_t emergency_reserve_max() { return 0; }
|
|
void clear_allocation_failure_flag() { }
|
|
bool allocation_failure_flag() { return false; }
|
|
void refill_emergency_reserve() {}
|
|
size_t trim_emergency_reserve_to_max() { return 0; }
|
|
void update_non_lsa_memory_in_use(ssize_t n) {
|
|
_non_lsa_memory_in_use += n;
|
|
}
|
|
size_t non_lsa_memory_in_use() const {
|
|
return _non_lsa_memory_in_use;
|
|
}
|
|
size_t total_memory_in_use() const {
|
|
return _non_lsa_memory_in_use + _segments_in_use * segment::size;
|
|
}
|
|
void set_region(const segment* seg, region::impl* r) {
|
|
set_region(descriptor(seg), r);
|
|
}
|
|
void set_region(segment_descriptor& desc, region::impl* r) {
|
|
desc._region = r;
|
|
}
|
|
size_t reclaim_segments(size_t target) { return 0; }
|
|
void reclaim_all_free_segments() { }
|
|
|
|
struct stats {
|
|
size_t segments_migrated;
|
|
size_t segments_compacted;
|
|
};
|
|
private:
|
|
stats _stats{};
|
|
public:
|
|
size_t zone_count() const { return 0; }
|
|
const stats& statistics() const { return _stats; }
|
|
void on_segment_migration() { _stats.segments_migrated++; }
|
|
void on_segment_compaction() { _stats.segments_compacted++; }
|
|
size_t free_segments_in_zones() const { return 0; }
|
|
size_t free_segments() const { return 0; }
|
|
public:
|
|
class reservation_goal;
|
|
};
|
|
|
|
#endif
|
|
|
|
// RAII wrapper to maintain segment_pool::current_emergency_reserve_goal()
|
|
class segment_pool::reservation_goal {
|
|
segment_pool& _sp;
|
|
size_t _old_goal;
|
|
public:
|
|
reservation_goal(segment_pool& sp, size_t goal)
|
|
: _sp(sp), _old_goal(_sp.current_emergency_reserve_goal()) {
|
|
_sp.set_current_emergency_reserve_goal(goal);
|
|
}
|
|
~reservation_goal() {
|
|
_sp.set_current_emergency_reserve_goal(_old_goal);
|
|
}
|
|
};
|
|
|
|
size_t segment_pool::segments_in_use() const {
|
|
return _segments_in_use;
|
|
}
|
|
|
|
static thread_local segment_pool shard_segment_pool;
|
|
|
|
void segment::record_alloc(segment::size_type size) {
|
|
shard_segment_pool.descriptor(this).record_alloc(size);
|
|
}
|
|
|
|
void segment::record_free(segment::size_type size) {
|
|
shard_segment_pool.descriptor(this).record_free(size);
|
|
}
|
|
|
|
bool segment::is_empty() const {
|
|
return shard_segment_pool.descriptor(this).is_empty();
|
|
}
|
|
|
|
occupancy_stats
|
|
segment::occupancy() const {
|
|
return { shard_segment_pool.descriptor(this)._free_space, segment::size };
|
|
}
|
|
|
|
//
|
|
// For interface documentation see logalloc::region and allocation_strategy.
|
|
//
|
|
// Allocation dynamics.
|
|
//
|
|
// Objects are allocated inside fixed-size segments. Objects don't cross
|
|
// segment boundary. Active allocations are served from a single segment using
|
|
// bump-the-pointer method. That segment is called the active segment. When
|
|
// active segment fills up, it is closed. Closed segments are kept in a heap
|
|
// which orders them by occupancy. As objects are freed, the segment become
|
|
// sparser and are eventually released. Objects which are too large are
|
|
// allocated using standard allocator.
|
|
//
|
|
// Segment layout.
|
|
//
|
|
// Objects in a segment are laid out sequentially. Each object is preceded by
|
|
// a descriptor (see object_descriptor). Object alignment is respected, so if
|
|
// there is a gap between the end of current object and the next object's
|
|
// descriptor, a trunk of the object descriptor is left right after the
|
|
// current object with the flags byte indicating the amount of padding.
|
|
//
|
|
// Per-segment metadata is kept in a separate array, managed by segment_pool
|
|
// object.
|
|
//
|
|
class region_impl final : public basic_region_impl {
|
|
// Serialized object descriptor format:
|
|
// byte0 byte1 ... byte[n-1]
|
|
// bit0-bit5: ULEB64 significand
|
|
// bit6: 1 iff first byte
|
|
// bit7: 1 iff last byte
|
|
// This format allows decoding both forwards and backwards (by scanning for bit7/bit6 respectively);
|
|
// backward decoding is needed to recover the descriptor from the object pointer when freeing.
|
|
//
|
|
// Significand interpretation (value = n):
|
|
// even: dead object, size n/2 (including descriptor)
|
|
// odd: migrate_fn_type at index n/2, from static_migrators()
|
|
class object_descriptor {
|
|
private:
|
|
uint32_t _n;
|
|
private:
|
|
explicit object_descriptor(uint32_t n) : _n(n) {}
|
|
public:
|
|
object_descriptor(allocation_strategy::migrate_fn migrator)
|
|
: _n(migrator->index() * 2 + 1)
|
|
{ }
|
|
|
|
static object_descriptor make_dead(size_t size) {
|
|
return object_descriptor(size * 2);
|
|
}
|
|
|
|
allocation_strategy::migrate_fn migrator() const {
|
|
return static_migrators()[_n / 2];
|
|
}
|
|
|
|
uint8_t alignment() const {
|
|
return migrator()->align();
|
|
}
|
|
|
|
// excluding descriptor
|
|
segment::size_type live_size(const void* obj) const {
|
|
return migrator()->size(obj);
|
|
}
|
|
|
|
// including descriptor
|
|
segment::size_type dead_size() const {
|
|
return _n / 2;
|
|
}
|
|
|
|
bool is_live() const {
|
|
return (_n & 1) == 1;
|
|
}
|
|
|
|
segment::size_type encoded_size() const {
|
|
return log2floor(_n) / 6 + 1; // 0 is illegal
|
|
}
|
|
|
|
void encode(char*& pos) const {
|
|
uint64_t b = 64;
|
|
auto n = _n;
|
|
do {
|
|
b |= n & 63;
|
|
n >>= 6;
|
|
if (!n) {
|
|
b |= 128;
|
|
}
|
|
*pos++ = b;
|
|
b = 0;
|
|
} while (n);
|
|
}
|
|
|
|
// non-canonical encoding to allow padding (for alignment); encoded_size must be
|
|
// sufficient (greater than this->encoded_size())
|
|
void encode(char*& pos, size_t encoded_size) const {
|
|
uint64_t b = 64;
|
|
auto n = _n;
|
|
do {
|
|
b |= n & 63;
|
|
n >>= 6;
|
|
if (!--encoded_size) {
|
|
b |= 128;
|
|
}
|
|
*pos++ = b;
|
|
b = 0;
|
|
} while (encoded_size);
|
|
}
|
|
|
|
static object_descriptor decode_forwards(const char*& pos) {
|
|
unsigned n = 0;
|
|
unsigned shift = 0;
|
|
auto p = pos; // avoid aliasing; p++ doesn't touch memory
|
|
uint8_t b;
|
|
do {
|
|
b = *p++;
|
|
if (shift < 32) {
|
|
// non-canonical encoding can cause large shift; undefined in C++
|
|
n |= uint32_t(b & 63) << shift;
|
|
}
|
|
shift += 6;
|
|
} while ((b & 128) == 0);
|
|
pos = p;
|
|
return object_descriptor(n);
|
|
}
|
|
|
|
static object_descriptor decode_backwards(const char*& pos) {
|
|
unsigned n = 0;
|
|
uint8_t b;
|
|
auto p = pos; // avoid aliasing; --p doesn't touch memory
|
|
do {
|
|
b = *--p;
|
|
n = (n << 6) | (b & 63);
|
|
} while ((b & 64) == 0);
|
|
pos = p;
|
|
return object_descriptor(n);
|
|
}
|
|
|
|
friend std::ostream& operator<<(std::ostream& out, const object_descriptor& desc) {
|
|
if (!desc.is_live()) {
|
|
return out << sprint("{free %d}", desc.dead_size());
|
|
} else {
|
|
auto m = desc.migrator();
|
|
auto x = reinterpret_cast<uintptr_t>(&desc) + sizeof(desc);
|
|
x = align_up(x, m->align());
|
|
auto obj = reinterpret_cast<const void*>(x);
|
|
return out << sprint("{migrator=%p, alignment=%d, size=%d}",
|
|
(void*)m, m->align(), m->size(obj));
|
|
}
|
|
}
|
|
};
|
|
private:
|
|
region* _region = nullptr;
|
|
region_group* _group = nullptr;
|
|
segment* _active = nullptr;
|
|
size_t _active_offset;
|
|
segment_descriptor_hist _segment_descs; // Contains only closed segments
|
|
occupancy_stats _closed_occupancy;
|
|
occupancy_stats _non_lsa_occupancy;
|
|
// This helps us keeping track of the region_group* heap. That's because we call update before
|
|
// we have a chance to update the occupancy stats - mainly because at this point we don't know
|
|
// what will we do with the new segment. Also, because we are not ever interested in the
|
|
// fraction used, we'll keep it as a scalar and convert when we need to present it as an
|
|
// occupancy. We could actually just present this as a scalar as well and never use occupancies,
|
|
// but consistency is good.
|
|
size_t _evictable_space = 0;
|
|
bool _evictable = false;
|
|
uint64_t _id;
|
|
eviction_fn _eviction_fn;
|
|
|
|
region_group::region_heap::handle_type _heap_handle;
|
|
private:
|
|
struct compaction_lock {
|
|
region_impl& _region;
|
|
bool _prev;
|
|
compaction_lock(region_impl& r)
|
|
: _region(r)
|
|
, _prev(r._reclaiming_enabled)
|
|
{
|
|
_region._reclaiming_enabled = false;
|
|
}
|
|
~compaction_lock() {
|
|
_region._reclaiming_enabled = _prev;
|
|
}
|
|
};
|
|
|
|
void* alloc_small(allocation_strategy::migrate_fn migrator, segment::size_type size, size_t alignment) {
|
|
if (!_active) {
|
|
_active = new_segment();
|
|
_active_offset = 0;
|
|
}
|
|
|
|
auto desc = object_descriptor(migrator);
|
|
auto desc_encoded_size = desc.encoded_size();
|
|
|
|
size_t obj_offset = align_up(_active_offset + desc_encoded_size, alignment);
|
|
if (obj_offset + size > segment::size) {
|
|
close_and_open();
|
|
return alloc_small(migrator, size, alignment);
|
|
}
|
|
|
|
auto old_active_offset = _active_offset;
|
|
auto pos = _active->at<char>(_active_offset);
|
|
// Use non-canonical encoding to allow for alignment pad
|
|
desc.encode(pos, obj_offset - _active_offset);
|
|
_active_offset = obj_offset + size;
|
|
_active->record_alloc(_active_offset - old_active_offset);
|
|
return pos;
|
|
}
|
|
|
|
template<typename Func>
|
|
void for_each_live(segment* seg, Func&& func) {
|
|
// scylla-gdb.py:scylla_lsa_segment is coupled with this implementation.
|
|
|
|
static_assert(std::is_same<void, std::result_of_t<Func(const object_descriptor*, void*)>>::value, "bad Func signature");
|
|
|
|
auto pos = seg->at<const char>(0);
|
|
while (pos < seg->at<const char>(segment::size)) {
|
|
auto old_pos = pos;
|
|
const auto desc = object_descriptor::decode_forwards(pos);
|
|
if (desc.is_live()) {
|
|
auto size = desc.live_size(pos);
|
|
func(&desc, const_cast<char*>(pos));
|
|
pos += size;
|
|
} else {
|
|
pos = old_pos + desc.dead_size();
|
|
}
|
|
}
|
|
}
|
|
|
|
void close_active() {
|
|
if (!_active) {
|
|
return;
|
|
}
|
|
if (_active_offset < segment::size) {
|
|
auto desc = object_descriptor::make_dead(segment::size - _active_offset);
|
|
auto pos =_active->at<char>(_active_offset);
|
|
desc.encode(pos);
|
|
}
|
|
llogger.trace("Closing segment {}, used={}, waste={} [B]", _active, _active->occupancy(), segment::size - _active_offset);
|
|
_closed_occupancy += _active->occupancy();
|
|
|
|
_segment_descs.push(shard_segment_pool.descriptor(_active));
|
|
_active = nullptr;
|
|
}
|
|
|
|
void free_segment(segment_descriptor& desc) noexcept {
|
|
free_segment(shard_segment_pool.segment_from(desc), desc);
|
|
}
|
|
|
|
void free_segment(segment* seg) noexcept {
|
|
free_segment(seg, shard_segment_pool.descriptor(seg));
|
|
}
|
|
|
|
void free_segment(segment* seg, segment_descriptor& desc) noexcept {
|
|
shard_segment_pool.free_segment(seg, desc);
|
|
if (_group) {
|
|
_evictable_space -= segment_size;
|
|
_group->decrease_usage(_heap_handle, -segment::size);
|
|
}
|
|
}
|
|
|
|
segment* new_segment() {
|
|
segment* seg = shard_segment_pool.new_segment(this);
|
|
if (_group) {
|
|
_evictable_space += segment_size;
|
|
_group->increase_usage(_heap_handle, segment::size);
|
|
}
|
|
return seg;
|
|
}
|
|
|
|
void compact(segment* seg, segment_descriptor& desc) {
|
|
++_invalidate_counter;
|
|
|
|
for_each_live(seg, [this] (const object_descriptor* desc, void* obj) {
|
|
auto size = desc->live_size(obj);
|
|
auto dst = alloc_small(desc->migrator(), size, desc->alignment());
|
|
desc->migrator()->migrate(obj, dst);
|
|
});
|
|
|
|
free_segment(seg, desc);
|
|
}
|
|
|
|
void close_and_open() {
|
|
segment* new_active = new_segment();
|
|
close_active();
|
|
_active = new_active;
|
|
_active_offset = 0;
|
|
}
|
|
|
|
static uint64_t next_id() {
|
|
static std::atomic<uint64_t> id{0};
|
|
return id.fetch_add(1);
|
|
}
|
|
struct degroup_temporarily {
|
|
region_impl* impl;
|
|
region_group* group;
|
|
explicit degroup_temporarily(region_impl* impl)
|
|
: impl(impl), group(impl->_group) {
|
|
if (group) {
|
|
group->del(impl);
|
|
}
|
|
}
|
|
~degroup_temporarily() {
|
|
if (group) {
|
|
group->add(impl);
|
|
}
|
|
}
|
|
};
|
|
|
|
public:
|
|
explicit region_impl(region* region, region_group* group = nullptr)
|
|
: _region(region), _group(group), _id(next_id())
|
|
{
|
|
_preferred_max_contiguous_allocation = max_managed_object_size;
|
|
tracker_instance._impl->register_region(this);
|
|
if (group) {
|
|
group->add(this);
|
|
}
|
|
}
|
|
|
|
virtual ~region_impl() {
|
|
tracker_instance._impl->unregister_region(this);
|
|
|
|
while (!_segment_descs.empty()) {
|
|
auto& desc = _segment_descs.one_of_largest();
|
|
_segment_descs.pop_one_of_largest();
|
|
assert(desc.is_empty());
|
|
free_segment(desc);
|
|
}
|
|
_closed_occupancy = {};
|
|
if (_active) {
|
|
assert(_active->is_empty());
|
|
free_segment(_active);
|
|
_active = nullptr;
|
|
}
|
|
if (_group) {
|
|
_group->del(this);
|
|
}
|
|
}
|
|
|
|
region_impl(region_impl&&) = delete;
|
|
region_impl(const region_impl&) = delete;
|
|
|
|
bool empty() const {
|
|
return occupancy().used_space() == 0;
|
|
}
|
|
|
|
occupancy_stats occupancy() const {
|
|
occupancy_stats total = _non_lsa_occupancy;
|
|
total += _closed_occupancy;
|
|
if (_active) {
|
|
total += _active->occupancy();
|
|
}
|
|
return total;
|
|
}
|
|
|
|
region_group* group() {
|
|
return _group;
|
|
}
|
|
|
|
occupancy_stats compactible_occupancy() const {
|
|
return _closed_occupancy;
|
|
}
|
|
|
|
occupancy_stats evictable_occupancy() const {
|
|
return occupancy_stats(_evictable_space, _evictable_space);
|
|
}
|
|
//
|
|
// Returns true if this region can be compacted and compact() will make forward progress,
|
|
// so that this will eventually stop:
|
|
//
|
|
// while (is_compactible()) { compact(); }
|
|
//
|
|
bool is_compactible() const {
|
|
return _reclaiming_enabled
|
|
&& (_closed_occupancy.free_space() >= 2 * segment::size)
|
|
&& _segment_descs.contains_above_min();
|
|
}
|
|
|
|
bool is_idle_compactible() {
|
|
return is_compactible();
|
|
}
|
|
|
|
virtual void* alloc(allocation_strategy::migrate_fn migrator, size_t size, size_t alignment) override {
|
|
compaction_lock _(*this);
|
|
memory::on_alloc_point();
|
|
if (size > max_managed_object_size) {
|
|
auto ptr = standard_allocator().alloc(migrator, size, alignment);
|
|
// This isn't very acurrate, the correct free_space value would be
|
|
// malloc_usable_size(ptr) - size, but there is no way to get
|
|
// the exact object size at free.
|
|
auto allocated_size = malloc_usable_size(ptr);
|
|
_non_lsa_occupancy += occupancy_stats(0, allocated_size);
|
|
if (_group) {
|
|
_evictable_space += allocated_size;
|
|
_group->increase_usage(_heap_handle, allocated_size);
|
|
}
|
|
shard_segment_pool.update_non_lsa_memory_in_use(allocated_size);
|
|
return ptr;
|
|
} else {
|
|
return alloc_small(migrator, (segment::size_type) size, alignment);
|
|
}
|
|
}
|
|
|
|
virtual void free(void* obj, size_t size) noexcept override {
|
|
compaction_lock _(*this);
|
|
segment* seg = shard_segment_pool.containing_segment(obj);
|
|
|
|
if (!seg) {
|
|
auto allocated_size = malloc_usable_size(obj);
|
|
_non_lsa_occupancy -= occupancy_stats(0, allocated_size);
|
|
if (_group) {
|
|
_evictable_space -= allocated_size;
|
|
_group->decrease_usage(_heap_handle, allocated_size);
|
|
}
|
|
shard_segment_pool.update_non_lsa_memory_in_use(-allocated_size);
|
|
standard_allocator().free(obj, size);
|
|
return;
|
|
}
|
|
|
|
segment_descriptor& seg_desc = shard_segment_pool.descriptor(seg);
|
|
|
|
auto pos = reinterpret_cast<const char*>(obj);
|
|
auto old_pos = pos;
|
|
auto desc = object_descriptor::decode_backwards(pos);
|
|
auto dead_size = size + (old_pos - pos);
|
|
desc = object_descriptor::make_dead(dead_size);
|
|
auto npos = const_cast<char*>(pos);
|
|
desc.encode(npos);
|
|
|
|
if (seg != _active) {
|
|
_closed_occupancy -= seg->occupancy();
|
|
}
|
|
|
|
seg_desc.record_free(dead_size);
|
|
|
|
if (seg != _active) {
|
|
if (seg_desc.is_empty()) {
|
|
_segment_descs.erase(seg_desc);
|
|
free_segment(seg, seg_desc);
|
|
} else {
|
|
_segment_descs.adjust_up(seg_desc);
|
|
_closed_occupancy += seg_desc.occupancy();
|
|
}
|
|
}
|
|
}
|
|
|
|
virtual size_t object_memory_size_in_allocator(const void* obj) const noexcept override {
|
|
segment* seg = shard_segment_pool.containing_segment(obj);
|
|
|
|
if (!seg) {
|
|
return standard_allocator().object_memory_size_in_allocator(obj);
|
|
} else {
|
|
auto pos = reinterpret_cast<const char*>(obj);
|
|
auto desc = object_descriptor::decode_backwards(pos);
|
|
return desc.encoded_size() + desc.live_size(obj);
|
|
}
|
|
}
|
|
|
|
// Merges another region into this region. The other region is made
|
|
// to refer to this region.
|
|
// Doesn't invalidate references to allocated objects.
|
|
void merge(region_impl& other) noexcept {
|
|
compaction_lock dct1(*this);
|
|
compaction_lock dct2(other);
|
|
degroup_temporarily dgt1(this);
|
|
degroup_temporarily dgt2(&other);
|
|
|
|
if (_active && _active->is_empty()) {
|
|
shard_segment_pool.free_segment(_active);
|
|
_active = nullptr;
|
|
}
|
|
if (!_active) {
|
|
_active = other._active;
|
|
other._active = nullptr;
|
|
_active_offset = other._active_offset;
|
|
if (_active) {
|
|
shard_segment_pool.set_region(_active, this);
|
|
}
|
|
} else {
|
|
other.close_active();
|
|
}
|
|
|
|
for (auto& desc : other._segment_descs) {
|
|
shard_segment_pool.set_region(desc, this);
|
|
}
|
|
_segment_descs.merge(other._segment_descs);
|
|
|
|
_closed_occupancy += other._closed_occupancy;
|
|
_non_lsa_occupancy += other._non_lsa_occupancy;
|
|
other._closed_occupancy = {};
|
|
other._non_lsa_occupancy = {};
|
|
|
|
// Make sure both regions will notice a future increment
|
|
// to the reclaim counter
|
|
_invalidate_counter = std::max(_invalidate_counter, other._invalidate_counter);
|
|
}
|
|
|
|
// Returns occupancy of the sparsest compactible segment.
|
|
occupancy_stats min_occupancy() const {
|
|
if (_segment_descs.empty()) {
|
|
return {};
|
|
}
|
|
return _segment_descs.one_of_largest().occupancy();
|
|
}
|
|
|
|
void compact_single_segment_locked() {
|
|
auto& desc = _segment_descs.one_of_largest();
|
|
_segment_descs.pop_one_of_largest();
|
|
_closed_occupancy -= desc.occupancy();
|
|
segment* seg = shard_segment_pool.segment_from(desc);
|
|
llogger.debug("Compacting segment {} from region {}, {}", seg, id(), seg->occupancy());
|
|
compact(seg, desc);
|
|
shard_segment_pool.on_segment_compaction();
|
|
}
|
|
|
|
// Compacts a single segment
|
|
void compact() {
|
|
compaction_lock _(*this);
|
|
compact_single_segment_locked();
|
|
}
|
|
|
|
void migrate_segment(segment* src, segment_descriptor& src_desc, segment* dst, segment_descriptor& dst_desc) {
|
|
++_invalidate_counter;
|
|
size_t segment_size;
|
|
if (src != _active) {
|
|
_segment_descs.erase(src_desc);
|
|
_segment_descs.push(dst_desc);
|
|
segment_size = segment::size;
|
|
} else {
|
|
_active = dst;
|
|
segment_size = _active_offset;
|
|
}
|
|
|
|
size_t offset = 0;
|
|
while (offset < segment_size) {
|
|
auto pos = src->at<const char>(offset);
|
|
auto dpos = dst->at<char>(offset);
|
|
auto old_pos = pos;
|
|
auto desc = object_descriptor::decode_forwards(pos);
|
|
// Keep same size as before to maintain alignment
|
|
desc.encode(dpos, pos - old_pos);
|
|
if (desc.is_live()) {
|
|
offset += pos - old_pos;
|
|
offset += desc.live_size(pos);
|
|
desc.migrator()->migrate(const_cast<char*>(pos), dpos);
|
|
} else {
|
|
offset += desc.dead_size();
|
|
}
|
|
}
|
|
shard_segment_pool.on_segment_migration();
|
|
}
|
|
|
|
// Compacts everything. Mainly for testing.
|
|
// Invalidates references to allocated objects.
|
|
void full_compaction() {
|
|
compaction_lock _(*this);
|
|
llogger.debug("Full compaction, {}", occupancy());
|
|
close_and_open();
|
|
segment_descriptor_hist all;
|
|
std::swap(all, _segment_descs);
|
|
_closed_occupancy = {};
|
|
while (!all.empty()) {
|
|
auto& desc = all.one_of_largest();
|
|
all.pop_one_of_largest();
|
|
compact(shard_segment_pool.segment_from(desc), desc);
|
|
}
|
|
llogger.debug("Done, {}", occupancy());
|
|
}
|
|
|
|
allocation_strategy& allocator() {
|
|
return *this;
|
|
}
|
|
|
|
uint64_t id() const {
|
|
return _id;
|
|
}
|
|
|
|
// Returns true if this pool is evictable, so that evict_some() can be called.
|
|
bool is_evictable() const {
|
|
return _evictable && _reclaiming_enabled;
|
|
}
|
|
|
|
memory::reclaiming_result evict_some() {
|
|
++_invalidate_counter;
|
|
return _eviction_fn();
|
|
}
|
|
|
|
void make_not_evictable() {
|
|
_evictable = false;
|
|
_eviction_fn = {};
|
|
}
|
|
|
|
void make_evictable(eviction_fn fn) {
|
|
_evictable = true;
|
|
_eviction_fn = std::move(fn);
|
|
}
|
|
|
|
const eviction_fn& evictor() const {
|
|
return _eviction_fn;
|
|
}
|
|
|
|
friend class region;
|
|
friend class region_group;
|
|
friend class region_group::region_evictable_occupancy_ascending_less_comparator;
|
|
};
|
|
|
|
inline void
|
|
region_group_binomial_group_sanity_check(const region_group::region_heap& bh) {
|
|
#ifdef DEBUG
|
|
bool failed = false;
|
|
size_t last = std::numeric_limits<size_t>::max();
|
|
for (auto b = bh.ordered_begin(); b != bh.ordered_end(); b++) {
|
|
auto t = (*b)->evictable_occupancy().total_space();
|
|
if (!(t <= last)) {
|
|
failed = true;
|
|
break;
|
|
}
|
|
last = t;
|
|
}
|
|
if (!failed) {
|
|
return;
|
|
}
|
|
|
|
printf("Sanity checking FAILED, size %ld\n", bh.size());
|
|
for (auto b = bh.ordered_begin(); b != bh.ordered_end(); b++) {
|
|
auto r = (*b);
|
|
auto t = r->evictable_occupancy().total_space();
|
|
printf(" r = %p (id=%ld), occupancy = %ld\n",r, r->id(), t);
|
|
}
|
|
assert(0);
|
|
#endif
|
|
}
|
|
|
|
void tracker::set_reclamation_step(size_t step_in_segments) {
|
|
_impl->set_reclamation_step(step_in_segments);
|
|
}
|
|
|
|
size_t tracker::reclamation_step() const {
|
|
return _impl->reclamation_step();
|
|
}
|
|
|
|
void tracker::enable_abort_on_bad_alloc() {
|
|
return _impl->enable_abort_on_bad_alloc();
|
|
}
|
|
|
|
bool tracker::should_abort_on_bad_alloc() {
|
|
return _impl->should_abort_on_bad_alloc();
|
|
}
|
|
|
|
memory::reclaiming_result tracker::reclaim() {
|
|
return reclaim(_impl->reclamation_step() * segment::size)
|
|
? memory::reclaiming_result::reclaimed_something
|
|
: memory::reclaiming_result::reclaimed_nothing;
|
|
}
|
|
|
|
bool
|
|
region_group::region_evictable_occupancy_ascending_less_comparator::operator()(region_impl* r1, region_impl* r2) const {
|
|
return r1->evictable_occupancy().total_space() < r2->evictable_occupancy().total_space();
|
|
}
|
|
|
|
region::region()
|
|
: _impl(make_shared<impl>(this))
|
|
{ }
|
|
|
|
region::region(region_group& group)
|
|
: _impl(make_shared<impl>(this, &group)) {
|
|
}
|
|
|
|
region_impl& region::get_impl() {
|
|
return *static_cast<region_impl*>(_impl.get());
|
|
}
|
|
const region_impl& region::get_impl() const {
|
|
return *static_cast<const region_impl*>(_impl.get());
|
|
}
|
|
|
|
region::region(region&& other) {
|
|
this->_impl = std::move(other._impl);
|
|
get_impl()._region = this;
|
|
}
|
|
|
|
region& region::operator=(region&& other) {
|
|
this->_impl = std::move(other._impl);
|
|
get_impl()._region = this;
|
|
return *this;
|
|
}
|
|
|
|
region::~region() {
|
|
}
|
|
|
|
occupancy_stats region::occupancy() const {
|
|
return get_impl().occupancy();
|
|
}
|
|
|
|
region_group* region::group() {
|
|
return get_impl().group();
|
|
}
|
|
|
|
void region::merge(region& other) noexcept {
|
|
if (_impl != other._impl) {
|
|
get_impl().merge(other.get_impl());
|
|
other._impl = _impl;
|
|
}
|
|
}
|
|
|
|
void region::full_compaction() {
|
|
get_impl().full_compaction();
|
|
}
|
|
|
|
memory::reclaiming_result region::evict_some() {
|
|
if (get_impl().is_evictable()) {
|
|
return get_impl().evict_some();
|
|
}
|
|
return memory::reclaiming_result::reclaimed_nothing;
|
|
}
|
|
|
|
void region::make_evictable(eviction_fn fn) {
|
|
get_impl().make_evictable(std::move(fn));
|
|
}
|
|
|
|
const eviction_fn& region::evictor() const {
|
|
return get_impl().evictor();
|
|
}
|
|
|
|
std::ostream& operator<<(std::ostream& out, const occupancy_stats& stats) {
|
|
return out << sprint("%.2f%%, %d / %d [B]",
|
|
stats.used_fraction() * 100, stats.used_space(), stats.total_space());
|
|
}
|
|
|
|
occupancy_stats tracker::impl::region_occupancy() {
|
|
reclaiming_lock _(*this);
|
|
occupancy_stats total{};
|
|
for (auto&& r: _regions) {
|
|
total += r->occupancy();
|
|
}
|
|
return total;
|
|
}
|
|
|
|
occupancy_stats tracker::impl::occupancy() {
|
|
reclaiming_lock _(*this);
|
|
auto occ = region_occupancy();
|
|
{
|
|
auto s = shard_segment_pool.free_segments() * segment::size;
|
|
occ += occupancy_stats(s, s);
|
|
}
|
|
return occ;
|
|
}
|
|
|
|
size_t tracker::impl::non_lsa_used_space() {
|
|
auto free_space_in_zones = shard_segment_pool.free_segments_in_zones() * segment_size;
|
|
return memory::stats().allocated_memory() - region_occupancy().total_space() - free_space_in_zones;
|
|
}
|
|
|
|
void tracker::impl::reclaim_all_free_segments()
|
|
{
|
|
llogger.debug("Reclaiming all free segments");
|
|
shard_segment_pool.trim_emergency_reserve_to_max();
|
|
shard_segment_pool.reclaim_all_free_segments();
|
|
llogger.debug("Reclamation done");
|
|
}
|
|
|
|
void tracker::impl::full_compaction() {
|
|
reclaiming_lock _(*this);
|
|
|
|
llogger.debug("Full compaction on all regions, {}", region_occupancy());
|
|
|
|
for (region_impl* r : _regions) {
|
|
if (r->reclaiming_enabled()) {
|
|
r->full_compaction();
|
|
}
|
|
}
|
|
|
|
llogger.debug("Compaction done, {}", region_occupancy());
|
|
}
|
|
|
|
static void reclaim_from_evictable(region::impl& r, size_t target_mem_in_use) {
|
|
while (true) {
|
|
auto deficit = shard_segment_pool.total_memory_in_use() - target_mem_in_use;
|
|
auto occupancy = r.occupancy();
|
|
auto used = occupancy.used_space();
|
|
if (used == 0) {
|
|
break;
|
|
}
|
|
auto used_target = used - std::min(used, deficit - std::min(deficit, occupancy.free_space()));
|
|
llogger.debug("Evicting {} bytes from region {}, occupancy={}", used - used_target, r.id(), r.occupancy());
|
|
while (r.occupancy().used_space() > used_target || !r.is_compactible()) {
|
|
if (r.evict_some() == memory::reclaiming_result::reclaimed_nothing) {
|
|
llogger.debug("Unable to evict more, evicted {} bytes", used - r.occupancy().used_space());
|
|
return;
|
|
}
|
|
if (shard_segment_pool.total_memory_in_use() <= target_mem_in_use) {
|
|
llogger.debug("Target met after evicting {} bytes", used - r.occupancy().used_space());
|
|
return;
|
|
}
|
|
if (r.empty()) {
|
|
return;
|
|
}
|
|
}
|
|
llogger.debug("Compacting after evicting {} bytes", used - r.occupancy().used_space());
|
|
r.compact();
|
|
}
|
|
}
|
|
|
|
struct reclaim_timer {
|
|
clock::time_point start;
|
|
bool enabled;
|
|
reclaim_timer() {
|
|
if (timing_logger.is_enabled(logging::log_level::debug)) {
|
|
start = clock::now();
|
|
enabled = true;
|
|
} else {
|
|
enabled = false;
|
|
}
|
|
}
|
|
~reclaim_timer() {
|
|
if (enabled) {
|
|
auto duration = clock::now() - start;
|
|
timing_logger.debug("Reclamation cycle took {} us.",
|
|
std::chrono::duration_cast<std::chrono::duration<double, std::micro>>(duration).count());
|
|
}
|
|
}
|
|
void stop(size_t released) {
|
|
if (enabled) {
|
|
enabled = false;
|
|
auto duration = clock::now() - start;
|
|
auto bytes_per_second = static_cast<float>(released) / std::chrono::duration_cast<std::chrono::duration<float>>(duration).count();
|
|
timing_logger.debug("Reclamation cycle took {} us. Reclamation rate = {} MiB/s",
|
|
std::chrono::duration_cast<std::chrono::duration<double, std::micro>>(duration).count(),
|
|
sprint("%.3f", bytes_per_second / (1024*1024)));
|
|
}
|
|
}
|
|
};
|
|
|
|
reactor::idle_cpu_handler_result tracker::impl::compact_on_idle(reactor::work_waiting_on_reactor check_for_work) {
|
|
if (!_reclaiming_enabled) {
|
|
return reactor::idle_cpu_handler_result::no_more_work;
|
|
}
|
|
reclaiming_lock rl(*this);
|
|
if (_regions.empty()) {
|
|
return reactor::idle_cpu_handler_result::no_more_work;
|
|
}
|
|
segment_pool::reservation_goal open_emergency_pool(shard_segment_pool, 0);
|
|
|
|
auto cmp = [] (region::impl* c1, region::impl* c2) {
|
|
if (c1->is_idle_compactible() != c2->is_idle_compactible()) {
|
|
return !c1->is_idle_compactible();
|
|
}
|
|
return c2->min_occupancy() < c1->min_occupancy();
|
|
};
|
|
|
|
boost::range::make_heap(_regions, cmp);
|
|
|
|
while (!check_for_work()) {
|
|
boost::range::pop_heap(_regions, cmp);
|
|
region::impl* r = _regions.back();
|
|
|
|
if (!r->is_idle_compactible()) {
|
|
return reactor::idle_cpu_handler_result::no_more_work;
|
|
}
|
|
|
|
r->compact();
|
|
|
|
boost::range::push_heap(_regions, cmp);
|
|
}
|
|
return reactor::idle_cpu_handler_result::interrupted_by_higher_priority_task;
|
|
}
|
|
|
|
size_t tracker::impl::reclaim(size_t memory_to_release) {
|
|
// Reclamation steps:
|
|
// 1. Try to release free segments from zones and emergency reserve.
|
|
// 2. Compact used segments and/or evict data.
|
|
|
|
if (!_reclaiming_enabled) {
|
|
return 0;
|
|
}
|
|
reclaiming_lock rl(*this);
|
|
reclaim_timer timing_guard;
|
|
|
|
size_t mem_released;
|
|
{
|
|
reclaiming_lock rl(*this);
|
|
constexpr auto max_bytes = std::numeric_limits<size_t>::max() - segment::size;
|
|
auto segments_to_release = align_up(std::min(max_bytes, memory_to_release), segment::size) >> segment::size_shift;
|
|
auto nr_released = shard_segment_pool.reclaim_segments(segments_to_release);
|
|
mem_released = nr_released * segment::size;
|
|
if (mem_released > memory_to_release) {
|
|
return memory_to_release;
|
|
}
|
|
}
|
|
return compact_and_evict_locked(memory_to_release - mem_released) + mem_released;
|
|
}
|
|
|
|
size_t tracker::impl::compact_and_evict(size_t memory_to_release) {
|
|
if (!_reclaiming_enabled) {
|
|
return 0;
|
|
}
|
|
reclaiming_lock rl(*this);
|
|
reclaim_timer timing_guard;
|
|
return compact_and_evict_locked(memory_to_release);
|
|
}
|
|
|
|
size_t tracker::impl::compact_and_evict_locked(size_t memory_to_release) {
|
|
//
|
|
// Algorithm outline.
|
|
//
|
|
// Regions are kept in a max-heap ordered so that regions with
|
|
// sparser segments are picked first. Non-compactible regions will be
|
|
// picked last. In each iteration we try to release one whole segment from
|
|
// the region which has the sparsest segment. We do it until we released
|
|
// enough segments or there are no more regions we can compact.
|
|
//
|
|
// When compaction is not sufficient to reclaim space, we evict data from
|
|
// evictable regions.
|
|
//
|
|
|
|
// This may run synchronously with allocation, so we should not allocate
|
|
// memory, otherwise we may get std::bad_alloc. Currently we only allocate
|
|
// in the logger when debug level is enabled. It's disabled during normal
|
|
// operation. Having it is still valuable during testing and in most cases
|
|
// should work just fine even if allocates.
|
|
|
|
size_t mem_released = 0;
|
|
|
|
size_t released_from_reserve = shard_segment_pool.trim_emergency_reserve_to_max() * segment::size;
|
|
mem_released += released_from_reserve;
|
|
if (mem_released >= memory_to_release) {
|
|
return mem_released;
|
|
}
|
|
|
|
size_t mem_in_use = shard_segment_pool.total_memory_in_use();
|
|
auto target_mem = mem_in_use - std::min(mem_in_use, memory_to_release - mem_released);
|
|
|
|
llogger.debug("Compacting, requested {} bytes, {} bytes in use, target is {}",
|
|
memory_to_release, mem_in_use, target_mem);
|
|
|
|
// Allow dipping into reserves while compacting
|
|
segment_pool::reservation_goal open_emergency_pool(shard_segment_pool, 0);
|
|
|
|
auto cmp = [] (region::impl* c1, region::impl* c2) {
|
|
if (c1->is_compactible() != c2->is_compactible()) {
|
|
return !c1->is_compactible();
|
|
}
|
|
return c2->min_occupancy() < c1->min_occupancy();
|
|
};
|
|
|
|
boost::range::make_heap(_regions, cmp);
|
|
|
|
if (llogger.is_enabled(logging::log_level::debug)) {
|
|
llogger.debug("Occupancy of regions:");
|
|
for (region::impl* r : _regions) {
|
|
llogger.debug(" - {}: min={}, avg={}", r->id(), r->min_occupancy(), r->compactible_occupancy());
|
|
}
|
|
}
|
|
|
|
while (shard_segment_pool.total_memory_in_use() > target_mem) {
|
|
boost::range::pop_heap(_regions, cmp);
|
|
region::impl* r = _regions.back();
|
|
|
|
if (!r->is_compactible()) {
|
|
llogger.trace("Unable to release segments, no compactible pools.");
|
|
break;
|
|
}
|
|
|
|
r->compact();
|
|
|
|
boost::range::push_heap(_regions, cmp);
|
|
}
|
|
|
|
auto released_during_compaction = mem_in_use - shard_segment_pool.total_memory_in_use();
|
|
|
|
if (shard_segment_pool.total_memory_in_use() > target_mem) {
|
|
llogger.debug("Considering evictable regions.");
|
|
// FIXME: Fair eviction
|
|
for (region::impl* r : _regions) {
|
|
if (r->is_evictable()) {
|
|
reclaim_from_evictable(*r, target_mem);
|
|
if (shard_segment_pool.total_memory_in_use() <= target_mem) {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
mem_released += mem_in_use - shard_segment_pool.total_memory_in_use();
|
|
|
|
llogger.debug("Released {} bytes (wanted {}), {} during compaction, {} from reserve",
|
|
mem_released, memory_to_release, released_during_compaction, released_from_reserve);
|
|
|
|
return mem_released;
|
|
}
|
|
|
|
#ifndef DEFAULT_ALLOCATOR
|
|
|
|
bool segment_pool::migrate_segment(segment* src, segment_zone& src_zone,
|
|
segment* dst, segment_zone& dst_zone)
|
|
{
|
|
auto& src_desc = descriptor(src);
|
|
auto& dst_desc = descriptor(dst);
|
|
|
|
llogger.debug("Migrating segment {} (zone @{}) to {} (zone @{}) (region @{})",
|
|
src, &src_zone, dst, &dst_zone, src_desc._region);
|
|
|
|
dst_desc._zone = &dst_zone;
|
|
assert(src_desc._zone == &src_zone);
|
|
if (src_desc._region) {
|
|
if (!src_desc._region->reclaiming_enabled()) {
|
|
llogger.trace("Cannot move segment {}", src);
|
|
return false;
|
|
}
|
|
dst_desc._lsa_managed = true;
|
|
dst_desc._free_space = src_desc._free_space;
|
|
src_desc._region->migrate_segment(src, src_desc, dst, dst_desc);
|
|
} else {
|
|
_emergency_reserve.replace(src, dst);
|
|
}
|
|
dst_desc._region = src_desc._region;
|
|
src_desc._lsa_managed = false;
|
|
src_desc._region = nullptr;
|
|
return true;
|
|
}
|
|
|
|
bool segment_zone::migrate_segment(size_t from, size_t to)
|
|
{
|
|
auto src = segment_from_position(from);
|
|
auto dst = segment_from_position(to);
|
|
return shard_segment_pool.migrate_segment(src, *this, dst, *this);
|
|
}
|
|
|
|
bool segment_zone::migrate_segments(segment_zone& dst_zone, size_t to_migrate)
|
|
{
|
|
_free_segments.clear_and_dispose([] (auto fseg) { fseg->~free_segment(); });
|
|
dst_zone._free_segments.clear_and_dispose([] (auto fseg) { fseg->~free_segment(); });
|
|
auto used_pos = _segments.find_last_clear();
|
|
auto free_pos = dst_zone._segments.find_first_set();
|
|
while (to_migrate-- && used_pos != utils::dynamic_bitset::npos && free_pos != utils::dynamic_bitset::npos) {
|
|
auto src = segment_from_position(used_pos);
|
|
auto dst = dst_zone.segment_from_position(free_pos);
|
|
auto could_migrate = shard_segment_pool.migrate_segment(src, *this, dst, dst_zone);
|
|
if (!could_migrate) {
|
|
return false;
|
|
}
|
|
_segments.set(used_pos);
|
|
_used_segment_count--;
|
|
dst_zone._segments.clear(free_pos);
|
|
dst_zone._used_segment_count++;
|
|
|
|
used_pos = _segments.find_previous_clear(used_pos);
|
|
free_pos = dst_zone._segments.find_next_set(free_pos);
|
|
}
|
|
return true;
|
|
}
|
|
|
|
#endif
|
|
|
|
void tracker::impl::register_region(region::impl* r) {
|
|
reclaiming_lock _(*this);
|
|
_regions.push_back(r);
|
|
llogger.debug("Registered region @{} with id={}", r, r->id());
|
|
}
|
|
|
|
void tracker::impl::unregister_region(region::impl* r) {
|
|
reclaiming_lock _(*this);
|
|
llogger.debug("Unregistering region, id={}", r->id());
|
|
_regions.erase(std::remove(_regions.begin(), _regions.end(), r));
|
|
}
|
|
|
|
tracker::impl::impl() {
|
|
namespace sm = seastar::metrics;
|
|
|
|
_metrics.add_group("lsa", {
|
|
sm::make_gauge("total_space_bytes", [this] { return region_occupancy().total_space(); },
|
|
sm::description("Holds a current size of allocated memory in bytes.")),
|
|
|
|
sm::make_gauge("used_space_bytes", [this] { return region_occupancy().used_space(); },
|
|
sm::description("Holds a current amount of used memory in bytes.")),
|
|
|
|
sm::make_gauge("small_objects_total_space_bytes", [this] { return region_occupancy().total_space() - shard_segment_pool.non_lsa_memory_in_use(); },
|
|
sm::description("Holds a current size of \"small objects\" memory region in bytes.")),
|
|
|
|
sm::make_gauge("small_objects_used_space_bytes", [this] { return region_occupancy().used_space() - shard_segment_pool.non_lsa_memory_in_use(); },
|
|
sm::description("Holds a current amount of used \"small objects\" memory in bytes.")),
|
|
|
|
sm::make_gauge("large_objects_total_space_bytes", [this] { return shard_segment_pool.non_lsa_memory_in_use(); },
|
|
sm::description("Holds a current size of allocated non-LSA memory.")),
|
|
|
|
sm::make_gauge("non_lsa_used_space_bytes", [this] { return non_lsa_used_space(); },
|
|
sm::description("Holds a current amount of used non-LSA memory.")),
|
|
|
|
sm::make_gauge("free_space_in_zones", [this] { return shard_segment_pool.free_segments_in_zones() * segment_size; },
|
|
sm::description("Holds a current amount of free memory in zones.")),
|
|
|
|
sm::make_gauge("occupancy", [this] { return region_occupancy().used_fraction() * 100; },
|
|
sm::description("Holds a current portion (in percents) of the used memory.")),
|
|
|
|
sm::make_gauge("zones", [this] { return shard_segment_pool.zone_count(); },
|
|
sm::description("Holds a current number of zones.")),
|
|
|
|
sm::make_derive("segments_migrated", [this] { return shard_segment_pool.statistics().segments_migrated; },
|
|
sm::description("Counts a number of migrated segments.")),
|
|
|
|
sm::make_derive("segments_compacted", [this] { return shard_segment_pool.statistics().segments_compacted; },
|
|
sm::description("Counts a number of compacted segments.")),
|
|
});
|
|
}
|
|
|
|
tracker::impl::~impl() {
|
|
if (!_regions.empty()) {
|
|
for (auto&& r : _regions) {
|
|
llogger.error("Region with id={} not unregistered!", r->id());
|
|
}
|
|
abort();
|
|
}
|
|
}
|
|
|
|
region_group_reclaimer region_group::no_reclaimer;
|
|
|
|
uint64_t region_group::top_region_evictable_space() const {
|
|
return _regions.empty() ? 0 : _regions.top()->evictable_occupancy().total_space();
|
|
}
|
|
|
|
region* region_group::get_largest_region() {
|
|
if (!_maximal_rg || _maximal_rg->_regions.empty()) {
|
|
return nullptr;
|
|
}
|
|
return _maximal_rg->_regions.top()->_region;
|
|
}
|
|
|
|
void
|
|
region_group::add(region_group* child) {
|
|
child->_subgroup_heap_handle = _subgroups.push(child);
|
|
update(child->_total_memory);
|
|
}
|
|
|
|
void
|
|
region_group::del(region_group* child) {
|
|
_subgroups.erase(child->_subgroup_heap_handle);
|
|
update(-child->_total_memory);
|
|
}
|
|
|
|
void
|
|
region_group::add(region_impl* child) {
|
|
child->_heap_handle = _regions.push(child);
|
|
region_group_binomial_group_sanity_check(_regions);
|
|
update(child->occupancy().total_space());
|
|
}
|
|
|
|
void
|
|
region_group::del(region_impl* child) {
|
|
_regions.erase(child->_heap_handle);
|
|
region_group_binomial_group_sanity_check(_regions);
|
|
update(-child->occupancy().total_space());
|
|
}
|
|
|
|
bool
|
|
region_group::execution_permitted() noexcept {
|
|
return do_for_each_parent(this, [] (auto rg) {
|
|
return rg->under_pressure() ? stop_iteration::yes : stop_iteration::no;
|
|
}) == nullptr;
|
|
}
|
|
|
|
future<>
|
|
region_group::start_releaser() {
|
|
return later().then([this] {
|
|
return repeat([this] () noexcept {
|
|
if (_shutdown_requested) {
|
|
return make_ready_future<stop_iteration>(stop_iteration::yes);
|
|
}
|
|
|
|
if (!_blocked_requests.empty() && execution_permitted()) {
|
|
auto req = std::move(_blocked_requests.front());
|
|
_blocked_requests.pop_front();
|
|
req->allocate();
|
|
return make_ready_future<stop_iteration>(stop_iteration::no);
|
|
} else {
|
|
// Block reclaiming to prevent signal() from being called by reclaimer inside wait()
|
|
// FIXME: handle allocation failures (not very likely) like allocating_section does
|
|
tracker_reclaimer_lock rl;
|
|
return _relief.wait().then([] {
|
|
return stop_iteration::no;
|
|
});
|
|
}
|
|
});
|
|
});
|
|
}
|
|
|
|
region_group::region_group(region_group *parent, region_group_reclaimer& reclaimer)
|
|
: _parent(parent)
|
|
, _reclaimer(reclaimer)
|
|
, _releaser(reclaimer_can_block() ? start_releaser() : make_ready_future<>())
|
|
{
|
|
if (_parent) {
|
|
_parent->add(this);
|
|
}
|
|
}
|
|
|
|
bool region_group::reclaimer_can_block() const {
|
|
return _reclaimer.throttle_threshold() != std::numeric_limits<size_t>::max();
|
|
}
|
|
|
|
void region_group::notify_relief() {
|
|
_relief.signal();
|
|
for (region_group* child : _subgroups) {
|
|
child->notify_relief();
|
|
}
|
|
}
|
|
|
|
void region_group::update(ssize_t delta) {
|
|
// Most-enclosing group which was relieved.
|
|
region_group* top_relief = nullptr;
|
|
|
|
do_for_each_parent(this, [&top_relief, delta] (region_group* rg) mutable {
|
|
rg->update_maximal_rg();
|
|
rg->_total_memory += delta;
|
|
|
|
if (rg->_total_memory >= rg->_reclaimer.soft_limit_threshold()) {
|
|
rg->_reclaimer.notify_soft_pressure();
|
|
} else {
|
|
rg->_reclaimer.notify_soft_relief();
|
|
}
|
|
|
|
if (rg->_total_memory > rg->_reclaimer.throttle_threshold()) {
|
|
rg->_reclaimer.notify_pressure();
|
|
} else if (rg->_reclaimer.under_pressure()) {
|
|
rg->_reclaimer.notify_relief();
|
|
top_relief = rg;
|
|
}
|
|
|
|
return stop_iteration::no;
|
|
});
|
|
|
|
if (top_relief) {
|
|
top_relief->notify_relief();
|
|
}
|
|
}
|
|
|
|
allocating_section::guard::guard()
|
|
: _prev(shard_segment_pool.emergency_reserve_max())
|
|
{ }
|
|
|
|
allocating_section::guard::~guard() {
|
|
shard_segment_pool.set_emergency_reserve_max(_prev);
|
|
}
|
|
|
|
#ifndef DEFAULT_ALLOCATOR
|
|
|
|
void allocating_section::reserve() {
|
|
shard_segment_pool.set_emergency_reserve_max(std::max(_lsa_reserve, _minimum_lsa_emergency_reserve));
|
|
shard_segment_pool.refill_emergency_reserve();
|
|
|
|
while (true) {
|
|
size_t free = memory::stats().free_memory();
|
|
if (free >= _std_reserve) {
|
|
break;
|
|
}
|
|
if (!tracker_instance.reclaim(_std_reserve - free)) {
|
|
throw std::bad_alloc();
|
|
}
|
|
}
|
|
|
|
shard_segment_pool.clear_allocation_failure_flag();
|
|
}
|
|
|
|
void allocating_section::on_alloc_failure(logalloc::region& r) {
|
|
r.allocator().invalidate_references();
|
|
if (shard_segment_pool.allocation_failure_flag()) {
|
|
_lsa_reserve *= 2; // FIXME: decay?
|
|
llogger.debug("LSA allocation failure, increasing reserve in section {} to {} segments", this, _lsa_reserve);
|
|
} else {
|
|
_std_reserve *= 2; // FIXME: decay?
|
|
llogger.debug("Standard allocator failure, increasing head-room in section {} to {} [B]", this, _std_reserve);
|
|
}
|
|
reserve();
|
|
}
|
|
|
|
#else
|
|
|
|
void allocating_section::reserve() {
|
|
}
|
|
|
|
void allocating_section::on_alloc_failure(logalloc::region&) {
|
|
throw std::bad_alloc();
|
|
}
|
|
|
|
#endif
|
|
|
|
void allocating_section::set_lsa_reserve(size_t reserve) {
|
|
_lsa_reserve = reserve;
|
|
}
|
|
|
|
void allocating_section::set_std_reserve(size_t reserve) {
|
|
_std_reserve = reserve;
|
|
}
|
|
|
|
void region_group::on_request_expiry::operator()(std::unique_ptr<allocating_function>& func) noexcept {
|
|
func->fail(std::make_exception_ptr(timed_out_error()));
|
|
}
|
|
|
|
}
|
|
|
|
// Orders segments by free space, assuming all segments have the same size.
|
|
// This avoids using the occupancy, which entails extra division operations.
|
|
template<>
|
|
size_t hist_key<logalloc::segment_descriptor>(const logalloc::segment_descriptor& desc) {
|
|
return desc._free_space;
|
|
}
|