af37a3fdbf
This patch moves a function using the region_impl type after the type has been defined. Signed-off-by: Duarte Nunes <duarte@scylladb.com> Message-Id: <20170418124551.25369-1-duarte@scylladb.com>
2201 lines
73 KiB
C++
2201 lines
73 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 "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_histogram.hh"
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namespace bi = boost::intrusive;
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standard_allocation_strategy standard_allocation_strategy_instance;
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namespace logalloc {
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struct segment;
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static logging::logger logger("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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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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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_shift = pow2_rank(segment::size * 0.1);
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static constexpr size_t max_managed_object_size = 1 << max_managed_object_size_shift;
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// Since we only compact if there's >= max_managed_object_size free space,
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// we use max_managed_object_size 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_histogram_options segment_descriptor_hist_options(max_managed_object_size_shift, 3, segment::size_shift);
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struct segment_descriptor : public log_histogram_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_histogram<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 initial_size = 64 * 1024;
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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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logger.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::initial_size;
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constexpr size_t segment_zone::minimum_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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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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logger.debug("Creating new zone @{}, size: {}", zone.get(), size);
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next_attempt_size = std::max(size << 1, minimum_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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logger.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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logger.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);
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friend void* segment::operator new(size_t);
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friend void segment::operator delete(void*);
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segment* allocate_or_fallback_to_reserve();
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void free_or_restore_to_reserve(segment* seg) noexcept;
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public:
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segment_pool();
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~segment_pool() {
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while (_emergency_reserve.size()) {
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deallocate_segment(_emergency_reserve.pop());
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}
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}
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segment* new_segment(region::impl* r);
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segment_descriptor& descriptor(const segment*);
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// Returns segment containing given object or nullptr.
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segment* containing_segment(const void* obj) const;
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segment* segment_from(const segment_descriptor& desc);
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void free_segment(segment*) noexcept;
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void free_segment(segment*, segment_descriptor&) noexcept;
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size_t segments_in_use() const;
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size_t current_emergency_reserve_goal() const { return _current_emergency_reserve_goal; }
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void set_emergency_reserve_max(size_t new_size) { _emergency_reserve_max = new_size; }
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size_t emergency_reserve_max() { return _emergency_reserve_max; }
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void set_current_emergency_reserve_goal(size_t goal) { _current_emergency_reserve_goal = goal; }
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void clear_allocation_failure_flag() { _allocation_failure_flag = false; }
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bool allocation_failure_flag() { return _allocation_failure_flag; }
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void refill_emergency_reserve();
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size_t trim_emergency_reserve_to_max();
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void update_non_lsa_memory_in_use(ssize_t n) {
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_non_lsa_memory_in_use += n;
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}
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size_t non_lsa_memory_in_use() const {
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return _non_lsa_memory_in_use;
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}
|
|
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;
|
|
}
|
|
|
|
logger.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()) {
|
|
if (reclaimed_segments < target || !zone.free_segment_count()) {
|
|
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
|
|
|
|
logger.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()) {
|
|
logger.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 {
|
|
logger.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 : public allocation_strategy {
|
|
static constexpr float max_occupancy_for_compaction = 0.85; // FIXME: make configurable
|
|
static constexpr float max_occupancy_for_compaction_on_idle = 0.93; // FIXME: make configurable
|
|
|
|
// single-byte flags
|
|
struct obj_flags {
|
|
static constexpr uint8_t live_flag = 0x01;
|
|
static constexpr uint8_t eos_flag = 0x02;
|
|
static constexpr size_t max_alignment = (0xff >> 2) + 1;
|
|
|
|
static uint8_t with_padding(uint8_t padding) {
|
|
assert(padding < max_alignment);
|
|
return uint8_t(padding << 2);
|
|
}
|
|
|
|
//
|
|
// bit 0: 0 = dead, 1 = live
|
|
// bit 1: when set, end-of-segment marker
|
|
// bits 2-7: The value represents padding in bytes between the end of previous object
|
|
// and this object's descriptor. Must be smaller than object's alignment, so max alignment is 64.
|
|
uint8_t _value;
|
|
|
|
obj_flags(uint8_t value)
|
|
: _value(value)
|
|
{ }
|
|
|
|
static obj_flags make_end_of_segment() {
|
|
return { eos_flag };
|
|
}
|
|
|
|
static obj_flags make_live(uint8_t padding) {
|
|
return obj_flags(live_flag | with_padding(padding));
|
|
}
|
|
|
|
static obj_flags make_padding(uint8_t padding) {
|
|
return obj_flags(with_padding(padding));
|
|
}
|
|
|
|
static obj_flags make_dead(uint8_t padding) {
|
|
return obj_flags(with_padding(padding));
|
|
}
|
|
|
|
// Number of bytes preceding this descriptor after the end of the previous object
|
|
uint8_t padding() const {
|
|
return _value >> 2;
|
|
}
|
|
|
|
bool is_live() const {
|
|
return _value & live_flag;
|
|
}
|
|
|
|
bool is_end_of_segment() const {
|
|
return _value & eos_flag;
|
|
}
|
|
|
|
void mark_dead() {
|
|
_value &= ~live_flag;
|
|
}
|
|
} __attribute__((packed));
|
|
|
|
class object_descriptor {
|
|
private:
|
|
obj_flags _flags;
|
|
uint8_t _alignment;
|
|
segment::size_type _size;
|
|
allocation_strategy::migrate_fn _migrator;
|
|
public:
|
|
object_descriptor(allocation_strategy::migrate_fn migrator, segment::size_type size, uint8_t alignment, uint8_t padding)
|
|
: _flags(obj_flags::make_live(padding))
|
|
, _alignment(alignment)
|
|
, _size(size)
|
|
, _migrator(migrator)
|
|
{ }
|
|
|
|
void mark_dead() {
|
|
_flags.mark_dead();
|
|
}
|
|
|
|
allocation_strategy::migrate_fn migrator() const {
|
|
return _migrator;
|
|
}
|
|
|
|
uint8_t alignment() const {
|
|
return _alignment;
|
|
}
|
|
|
|
segment::size_type size() const {
|
|
return _size;
|
|
}
|
|
|
|
obj_flags flags() const {
|
|
return _flags;
|
|
}
|
|
|
|
bool is_live() const {
|
|
return _flags.is_live();
|
|
}
|
|
|
|
bool is_end_of_segment() const {
|
|
return _flags.is_end_of_segment();
|
|
}
|
|
|
|
uint8_t padding() const {
|
|
return _flags.padding();
|
|
}
|
|
|
|
friend std::ostream& operator<<(std::ostream& out, const object_descriptor& desc) {
|
|
return out << sprint("{flags = %x, migrator=%p, alignment=%d, size=%d}",
|
|
(int)desc._flags._value, (void*)desc._migrator, unsigned(desc._alignment), desc._size);
|
|
}
|
|
} __attribute__((packed));
|
|
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 _reclaiming_enabled = true;
|
|
bool _evictable = false;
|
|
uint64_t _id;
|
|
uint64_t _reclaim_counter = 0;
|
|
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) {
|
|
assert(alignment < obj_flags::max_alignment);
|
|
|
|
if (!_active) {
|
|
_active = new_segment();
|
|
_active_offset = 0;
|
|
}
|
|
|
|
size_t obj_offset = align_up(_active_offset + sizeof(object_descriptor), alignment);
|
|
if (obj_offset + size > segment::size) {
|
|
close_and_open();
|
|
return alloc_small(migrator, size, alignment);
|
|
}
|
|
|
|
auto descriptor_offset = obj_offset - sizeof(object_descriptor);
|
|
auto padding = descriptor_offset - _active_offset;
|
|
|
|
new (_active->at(_active_offset)) obj_flags(obj_flags::make_padding(padding));
|
|
new (_active->at(descriptor_offset)) object_descriptor(migrator, size, alignment, padding);
|
|
|
|
void* obj = _active->at(obj_offset);
|
|
_active_offset = obj_offset + size;
|
|
_active->record_alloc(size + sizeof(object_descriptor) + padding);
|
|
return obj;
|
|
}
|
|
|
|
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(object_descriptor*, void*)>>::value, "bad Func signature");
|
|
|
|
size_t offset = 0;
|
|
while (offset < segment::size) {
|
|
object_descriptor* desc = seg->at<object_descriptor>(offset);
|
|
offset += desc->flags().padding();
|
|
desc = seg->at<object_descriptor>(offset);
|
|
if (desc->is_end_of_segment()) {
|
|
break;
|
|
}
|
|
offset += sizeof(object_descriptor);
|
|
if (desc->is_live()) {
|
|
func(desc, seg->at(offset));
|
|
}
|
|
offset += desc->size();
|
|
}
|
|
}
|
|
|
|
void close_active() {
|
|
if (!_active) {
|
|
return;
|
|
}
|
|
if (_active_offset < segment::size) {
|
|
new (_active->at(_active_offset)) obj_flags(obj_flags::make_end_of_segment());
|
|
}
|
|
logger.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) {
|
|
++_reclaim_counter;
|
|
|
|
for_each_live(seg, [this] (object_descriptor* desc, void* obj) {
|
|
auto dst = alloc_small(desc->migrator(), desc->size(), desc->alignment());
|
|
desc->migrator()->migrate(obj, dst, desc->size());
|
|
});
|
|
|
|
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)
|
|
&& (_closed_occupancy.used_fraction() < max_occupancy_for_compaction)
|
|
&& (_segment_descs.contains_above_min());
|
|
}
|
|
|
|
bool is_idle_compactible() {
|
|
return _reclaiming_enabled
|
|
&& (_closed_occupancy.free_space() >= 2 * segment::size)
|
|
&& (_closed_occupancy.used_fraction() < max_occupancy_for_compaction_on_idle)
|
|
&& (_segment_descs.contains_above_min());
|
|
}
|
|
|
|
virtual void* alloc(allocation_strategy::migrate_fn migrator, size_t size, size_t alignment) override {
|
|
compaction_lock _(*this);
|
|
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) 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);
|
|
return;
|
|
}
|
|
|
|
segment_descriptor& seg_desc = shard_segment_pool.descriptor(seg);
|
|
|
|
auto desc = reinterpret_cast<object_descriptor*>(reinterpret_cast<uintptr_t>(obj) - sizeof(object_descriptor));
|
|
desc->mark_dead();
|
|
|
|
if (seg != _active) {
|
|
_closed_occupancy -= seg->occupancy();
|
|
}
|
|
|
|
seg_desc.record_free(desc->size() + sizeof(object_descriptor) + desc->padding());
|
|
|
|
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 desc = reinterpret_cast<object_descriptor*>(reinterpret_cast<uintptr_t>(obj) - sizeof(object_descriptor));
|
|
return sizeof(object_descriptor) + desc->size();
|
|
}
|
|
}
|
|
|
|
// 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) {
|
|
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
|
|
_reclaim_counter = std::max(_reclaim_counter, other._reclaim_counter);
|
|
}
|
|
|
|
// Returns occupancy of the sparsest compactible segment.
|
|
occupancy_stats min_occupancy() const {
|
|
if (_segment_descs.empty()) {
|
|
return {};
|
|
}
|
|
return _segment_descs.largest().occupancy();
|
|
}
|
|
|
|
// Tries to release one full segment back to the segment pool.
|
|
void compact() {
|
|
if (!is_compactible()) {
|
|
return;
|
|
}
|
|
|
|
compaction_lock _(*this);
|
|
|
|
auto in_use = shard_segment_pool.segments_in_use();
|
|
while (shard_segment_pool.segments_in_use() >= in_use) {
|
|
compact_single_segment_locked();
|
|
}
|
|
}
|
|
|
|
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);
|
|
logger.debug("Compacting segment {} from region {}, {}", seg, id(), seg->occupancy());
|
|
compact(seg, desc);
|
|
shard_segment_pool.on_segment_compaction();
|
|
}
|
|
|
|
// Compacts only a single segment
|
|
void compact_on_idle() {
|
|
compaction_lock _(*this);
|
|
compact_single_segment_locked();
|
|
}
|
|
|
|
void migrate_segment(segment* src, segment_descriptor& src_desc, segment* dst, segment_descriptor& dst_desc) {
|
|
++_reclaim_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) {
|
|
obj_flags* oflags = src->at<obj_flags>(offset);
|
|
new (dst->at(offset)) obj_flags(*oflags);
|
|
offset += oflags->padding();
|
|
if (oflags->is_end_of_segment() && !oflags->is_live()) {
|
|
break;
|
|
}
|
|
|
|
object_descriptor* desc = src->at<object_descriptor>(offset);
|
|
new (dst->at(offset)) object_descriptor(*desc);
|
|
|
|
offset += sizeof(object_descriptor);
|
|
if (desc->is_live()) {
|
|
desc->migrator()->migrate(src->at(offset),
|
|
dst->at(offset), desc->size());
|
|
}
|
|
offset += desc->size();
|
|
if (desc->is_end_of_segment()) {
|
|
break;
|
|
}
|
|
}
|
|
shard_segment_pool.on_segment_migration();
|
|
}
|
|
|
|
// Compacts everything. Mainly for testing.
|
|
// Invalidates references to allocated objects.
|
|
void full_compaction() {
|
|
compaction_lock _(*this);
|
|
logger.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);
|
|
}
|
|
logger.debug("Done, {}", occupancy());
|
|
}
|
|
|
|
allocation_strategy& allocator() {
|
|
return *this;
|
|
}
|
|
|
|
uint64_t id() const {
|
|
return _id;
|
|
}
|
|
|
|
void set_reclaiming_enabled(bool enabled) {
|
|
_reclaiming_enabled = enabled;
|
|
}
|
|
|
|
bool reclaiming_enabled() const {
|
|
return _reclaiming_enabled;
|
|
}
|
|
|
|
// 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() {
|
|
++_reclaim_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);
|
|
}
|
|
|
|
uint64_t reclaim_counter() const {
|
|
return _reclaim_counter;
|
|
}
|
|
|
|
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::region(region&& other) {
|
|
this->_impl = std::move(other._impl);
|
|
this->_impl->_region = this;
|
|
}
|
|
|
|
region& region::operator=(region&& other) {
|
|
this->_impl = std::move(other._impl);
|
|
this->_impl->_region = this;
|
|
return *this;
|
|
}
|
|
|
|
region::~region() {
|
|
}
|
|
|
|
occupancy_stats region::occupancy() const {
|
|
return _impl->occupancy();
|
|
}
|
|
|
|
region_group* region::group() {
|
|
return _impl->group();
|
|
}
|
|
|
|
void region::merge(region& other) {
|
|
if (_impl != other._impl) {
|
|
_impl->merge(*other._impl);
|
|
other._impl = _impl;
|
|
}
|
|
}
|
|
|
|
void region::full_compaction() {
|
|
_impl->full_compaction();
|
|
}
|
|
|
|
memory::reclaiming_result region::evict_some() {
|
|
if (_impl->is_evictable()) {
|
|
return _impl->evict_some();
|
|
}
|
|
return memory::reclaiming_result::reclaimed_nothing;
|
|
}
|
|
|
|
void region::make_evictable(eviction_fn fn) {
|
|
_impl->make_evictable(std::move(fn));
|
|
}
|
|
|
|
allocation_strategy& region::allocator() {
|
|
return *_impl;
|
|
}
|
|
|
|
void region::set_reclaiming_enabled(bool compactible) {
|
|
_impl->set_reclaiming_enabled(compactible);
|
|
}
|
|
|
|
bool region::reclaiming_enabled() const {
|
|
return _impl->reclaiming_enabled();
|
|
}
|
|
|
|
uint64_t region::reclaim_counter() const {
|
|
return _impl->reclaim_counter();
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
void tracker::impl::reclaim_all_free_segments()
|
|
{
|
|
logger.debug("Reclaiming all free segments");
|
|
shard_segment_pool.trim_emergency_reserve_to_max();
|
|
shard_segment_pool.reclaim_all_free_segments();
|
|
logger.debug("Reclamation done");
|
|
}
|
|
|
|
void tracker::impl::full_compaction() {
|
|
reclaiming_lock _(*this);
|
|
|
|
logger.debug("Full compaction on all regions, {}", region_occupancy());
|
|
|
|
for (region_impl* r : _regions) {
|
|
if (r->reclaiming_enabled()) {
|
|
r->full_compaction();
|
|
}
|
|
}
|
|
|
|
logger.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()));
|
|
logger.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) {
|
|
logger.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) {
|
|
logger.debug("Target met after evicting {} bytes", used - r.occupancy().used_space());
|
|
return;
|
|
}
|
|
if (r.empty()) {
|
|
return;
|
|
}
|
|
}
|
|
logger.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_on_idle();
|
|
|
|
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);
|
|
|
|
logger.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 (logger.is_enabled(logging::log_level::debug)) {
|
|
logger.debug("Occupancy of regions:");
|
|
for (region::impl* r : _regions) {
|
|
logger.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()) {
|
|
logger.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) {
|
|
logger.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();
|
|
|
|
logger.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);
|
|
|
|
logger.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()) {
|
|
logger.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);
|
|
logger.debug("Registered region @{} with id={}", r, r->id());
|
|
}
|
|
|
|
void tracker::impl::unregister_region(region::impl* r) {
|
|
reclaiming_lock _(*this);
|
|
logger.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] {
|
|
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;
|
|
}, 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) {
|
|
logger.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::guard::enter(allocating_section& self) {
|
|
shard_segment_pool.set_emergency_reserve_max(std::max(self._lsa_reserve, _prev));
|
|
shard_segment_pool.refill_emergency_reserve();
|
|
|
|
while (true) {
|
|
size_t free = memory::stats().free_memory();
|
|
if (free >= self._std_reserve) {
|
|
break;
|
|
}
|
|
if (!tracker_instance.reclaim(self._std_reserve - free)) {
|
|
throw std::bad_alloc();
|
|
}
|
|
}
|
|
|
|
shard_segment_pool.clear_allocation_failure_flag();
|
|
}
|
|
|
|
void allocating_section::on_alloc_failure() {
|
|
if (shard_segment_pool.allocation_failure_flag()) {
|
|
_lsa_reserve *= 2; // FIXME: decay?
|
|
logger.debug("LSA allocation failure, increasing reserve in section {} to {} segments", this, _lsa_reserve);
|
|
} else {
|
|
_std_reserve *= 2; // FIXME: decay?
|
|
logger.debug("Standard allocator failure, increasing head-room in section {} to {} [B]", this, _std_reserve);
|
|
}
|
|
}
|
|
|
|
#else
|
|
|
|
void allocating_section::guard::enter(allocating_section& self) {
|
|
}
|
|
|
|
void allocating_section::on_alloc_failure() {
|
|
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;
|
|
}
|