0eb2eb1b44
Also add a comment to explain why it exists. Signed-off-by: Michael Livshin <michael.livshin@scylladb.com> Closes #9123
2729 lines
95 KiB
C++
2729 lines
95 KiB
C++
/*
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* Copyright (C) 2015-present 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/core/reactor.hh>
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#include <seastar/core/coroutine.hh>
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#include <seastar/core/with_scheduling_group.hh>
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#include <seastar/util/alloc_failure_injector.hh>
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#include <seastar/util/backtrace.hh>
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#include <seastar/util/later.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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#include "utils/preempt.hh"
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#include "utils/vle.hh"
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#include "utils/coarse_steady_clock.hh"
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#include <random>
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#include <chrono>
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using namespace std::chrono_literals;
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#ifdef SEASTAR_ASAN_ENABLED
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#include "sanitizer/asan_interface.h"
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// For each aligned 8 byte segment, the algorithm used by address
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// sanitizer can represent any addressable prefix followd by a
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// poisoned suffix. The details are at:
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// https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm
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// For us this means that:
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// * The descriptor must be 8 byte aligned. If it was not, making the
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// descriptor addressable would also make the end of the previous
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// value addressable.
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// * Each value must be at least 8 byte aligned. If it was not, making
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// the value addressable would also make the end of the descriptor
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// addressable.
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namespace debug {
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constexpr size_t logalloc_alignment = 8;
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}
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template<typename T>
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[[nodiscard]] static T align_up_for_asan(T val) {
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return align_up(val, size_t(8));
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}
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template<typename T>
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void poison(const T* addr, size_t size) {
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// Both values and descriptors must be aligned.
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assert(uintptr_t(addr) % 8 == 0);
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// This can be followed by
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// * 8 byte aligned descriptor (this is a value)
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// * 8 byte aligned value
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// * dead value
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// * end of segment
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// In all cases, we can align up the size to guarantee that asan
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// is able to poison this.
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ASAN_POISON_MEMORY_REGION(addr, align_up_for_asan(size));
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}
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void unpoison(const char *addr, size_t size) {
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ASAN_UNPOISON_MEMORY_REGION(addr, size);
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}
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#else
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namespace debug {
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constexpr size_t logalloc_alignment = 1;
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}
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template<typename T>
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[[nodiscard]] static T align_up_for_asan(T val) { return val; }
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template<typename T>
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void poison(const T* addr, size_t size) { }
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void unpoison(const char *addr, size_t size) { }
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#endif
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namespace bi = boost::intrusive;
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standard_allocation_strategy standard_allocation_strategy_instance;
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namespace {
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class migrators_base {
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protected:
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std::vector<const migrate_fn_type*> _migrators;
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};
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#ifdef DEBUG_LSA_SANITIZER
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class migrators : public migrators_base, public enable_lw_shared_from_this<migrators> {
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private:
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struct backtrace_entry {
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saved_backtrace _registration;
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saved_backtrace _deregistration;
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};
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std::vector<std::unique_ptr<backtrace_entry>> _backtraces;
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static logging::logger _logger;
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private:
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void on_error() { abort(); }
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public:
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uint32_t add(const migrate_fn_type* m) {
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_migrators.push_back(m);
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_backtraces.push_back(std::make_unique<backtrace_entry>(backtrace_entry{current_backtrace(), {}}));
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return _migrators.size() - 1;
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}
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void remove(uint32_t idx) {
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if (idx >= _migrators.size()) {
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_logger.error("Attempting to deregister migrator id {} which was never registered:\n{}",
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idx, current_backtrace());
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on_error();
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}
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if (!_migrators[idx]) {
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_logger.error("Attempting to double deregister migrator id {}:\n{}\n"
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"Previously deregistered at:\n{}\nRegistered at:\n{}",
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idx, current_backtrace(), _backtraces[idx]->_deregistration,
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_backtraces[idx]->_registration);
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on_error();
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}
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_migrators[idx] = nullptr;
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_backtraces[idx]->_deregistration = current_backtrace();
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}
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const migrate_fn_type*& operator[](uint32_t idx) {
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if (idx >= _migrators.size()) {
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_logger.error("Attempting to use migrator id {} that was never registered:\n{}",
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idx, current_backtrace());
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on_error();
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}
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if (!_migrators[idx]) {
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_logger.error("Attempting to use deregistered migrator id {}:\n{}\n"
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"Deregistered at:\n{}\nRegistered at:\n{}",
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idx, current_backtrace(), _backtraces[idx]->_deregistration,
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_backtraces[idx]->_registration);
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on_error();
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}
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return _migrators[idx];
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}
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};
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logging::logger migrators::_logger("lsa-migrator-sanitizer");
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#else
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class migrators : public migrators_base, public enable_lw_shared_from_this<migrators> {
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std::vector<uint32_t> _unused_ids;
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public:
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uint32_t add(const migrate_fn_type* m) {
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if (!_unused_ids.empty()) {
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uint32_t idx = _unused_ids.back();
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_unused_ids.pop_back();
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_migrators[idx] = m;
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return idx;
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}
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_migrators.push_back(m);
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return _migrators.size() - 1;
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}
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void remove(uint32_t idx) {
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_unused_ids.push_back(idx);
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}
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const migrate_fn_type*& operator[](uint32_t idx) {
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return _migrators[idx];
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}
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};
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#endif
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static
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migrators&
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static_migrators() noexcept {
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memory::scoped_critical_alloc_section dfg;
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static thread_local lw_shared_ptr<migrators> obj = make_lw_shared<migrators>();
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return *obj;
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}
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}
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namespace debug {
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thread_local migrators* static_migrators = &::static_migrators();
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}
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uint32_t
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migrate_fn_type::register_migrator(migrate_fn_type* m) {
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auto& migrators = *debug::static_migrators;
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auto idx = migrators.add(m);
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// object_descriptor encodes 2 * index() + 1
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assert(idx * 2 + 1 < utils::uleb64_express_supreme);
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m->_migrators = migrators.shared_from_this();
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return idx;
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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().remove(index);
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}
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namespace logalloc {
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static thread_local bool s_sanitizer_report_backtrace = false;
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#ifdef DEBUG_LSA_SANITIZER
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class region_sanitizer {
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struct allocation {
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size_t size;
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saved_backtrace backtrace;
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};
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private:
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static logging::logger logger;
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bool _broken = false;
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std::unordered_map<const void*, allocation> _allocations;
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private:
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template<typename Function>
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void run_and_handle_errors(Function&& fn) noexcept {
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memory::scoped_critical_alloc_section dfg;
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if (_broken) {
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return;
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}
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try {
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fn();
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} catch (...) {
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logger.error("Internal error, disabling the sanitizer: {}", std::current_exception());
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_broken = true;
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_allocations.clear();
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}
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}
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private:
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void on_error() { abort(); }
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public:
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void on_region_destruction() noexcept {
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run_and_handle_errors([&] {
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if (_allocations.empty()) {
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return;
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}
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for (auto [ptr, alloc] : _allocations) {
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logger.error("Leaked {} byte object at {} allocated from:\n{}",
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alloc.size, ptr, alloc.backtrace);
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}
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on_error();
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});
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}
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void on_allocation(const void* ptr, size_t size) noexcept {
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run_and_handle_errors([&] {
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auto backtrace = s_sanitizer_report_backtrace ? current_backtrace() : saved_backtrace();
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auto [ it, success ] = _allocations.emplace(ptr, allocation { size, std::move(backtrace) });
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if (!success) {
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logger.error("Attempting to allocate an {} byte object at an already occupied address {}:\n{}\n"
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"Previous allocation of {} bytes:\n{}",
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ptr, size, current_backtrace(), it->second.size, it->second.backtrace);
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on_error();
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}
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});
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}
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void on_free(const void* ptr, size_t size) noexcept {
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run_and_handle_errors([&] {
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auto it = _allocations.find(ptr);
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if (it == _allocations.end()) {
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logger.error("Attempting to free an object at {} (size: {}) that does not exist\n{}",
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ptr, size, current_backtrace());
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on_error();
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}
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if (it->second.size != size) {
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logger.error("Mismatch between allocation and deallocation size of object at {}: {} vs. {}:\n{}\n"
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"Allocated at:\n{}",
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ptr, it->second.size, size, current_backtrace(), it->second.backtrace);
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on_error();
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}
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_allocations.erase(it);
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});
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}
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void on_migrate(const void* src, size_t size, const void* dst) noexcept {
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run_and_handle_errors([&] {
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auto it_src = _allocations.find(src);
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if (it_src == _allocations.end()) {
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logger.error("Attempting to migrate an object at {} (size: {}) that does not exist",
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src, size);
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on_error();
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}
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if (it_src->second.size != size) {
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logger.error("Mismatch between allocation and migration size of object at {}: {} vs. {}\n"
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"Allocated at:\n{}",
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src, it_src->second.size, size, it_src->second.backtrace);
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on_error();
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}
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auto [ it_dst, success ] = _allocations.emplace(dst, std::move(it_src->second));
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if (!success) {
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logger.error("Attempting to migrate an {} byte object to an already occupied address {}:\n"
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"Migrated object allocated from:\n{}\n"
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"Previous allocation of {} bytes at the destination:\n{}",
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size, dst, it_src->second.backtrace, it_dst->second.size, it_dst->second.backtrace);
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on_error();
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}
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_allocations.erase(it_src);
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});
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}
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void merge(region_sanitizer& other) noexcept {
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run_and_handle_errors([&] {
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_broken = other._broken;
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if (_broken) {
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_allocations.clear();
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} else {
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_allocations.merge(other._allocations);
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if (!other._allocations.empty()) {
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for (auto [ptr, o_alloc] : other._allocations) {
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auto& alloc = _allocations.at(ptr);
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logger.error("Conflicting allocations at address {} in merged regions\n"
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"{} bytes allocated from:\n{}\n"
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"{} bytes allocated from:\n{}",
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ptr, alloc.size, alloc.backtrace, o_alloc.size, o_alloc.backtrace);
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}
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on_error();
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}
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}
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});
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}
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};
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logging::logger region_sanitizer::logger("lsa-sanitizer");
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#else
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struct region_sanitizer {
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void on_region_destruction() noexcept { }
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void on_allocation(const void*, size_t) noexcept { }
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void on_free(const void* ptr, size_t size) noexcept { }
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void on_migrate(const void*, size_t, const void*) noexcept { }
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void merge(region_sanitizer&) noexcept { }
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};
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#endif
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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 tracker& get_tracker_instance() noexcept {
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memory::scoped_critical_alloc_section dfg;
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static thread_local tracker obj;
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return obj;
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}
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static thread_local tracker& tracker_instance = get_tracker_instance();
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using clock = std::chrono::steady_clock;
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class background_reclaimer {
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scheduling_group _sg;
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noncopyable_function<void (size_t target)> _reclaim;
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timer<lowres_clock> _adjust_shares_timer;
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// If engaged, main loop is not running, set_value() to wake it.
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promise<>* _main_loop_wait = nullptr;
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future<> _done;
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bool _stopping = false;
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static constexpr size_t free_memory_threshold = 60'000'000;
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private:
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bool have_work() const {
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#ifndef SEASTAR_DEFAULT_ALLOCATOR
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return memory::stats().free_memory() < free_memory_threshold;
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#else
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return false;
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#endif
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}
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void main_loop_wake() {
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llogger.debug("background_reclaimer::main_loop_wake: waking {}", bool(_main_loop_wait));
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if (_main_loop_wait) {
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_main_loop_wait->set_value();
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_main_loop_wait = nullptr;
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}
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}
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future<> main_loop() {
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llogger.debug("background_reclaimer::main_loop: entry");
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while (true) {
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while (!_stopping && !have_work()) {
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promise<> wait;
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_main_loop_wait = &wait;
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llogger.trace("background_reclaimer::main_loop: sleep");
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co_await wait.get_future();
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llogger.trace("background_reclaimer::main_loop: awakened");
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_main_loop_wait = nullptr;
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}
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if (_stopping) {
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break;
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}
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_reclaim(free_memory_threshold - memory::stats().free_memory());
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co_await make_ready_future<>();
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}
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llogger.debug("background_reclaimer::main_loop: exit");
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}
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void adjust_shares() {
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if (have_work()) {
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auto shares = 1 + (1000 * (free_memory_threshold - memory::stats().free_memory())) / free_memory_threshold;
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_sg.set_shares(shares);
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llogger.trace("background_reclaimer::adjust_shares: {}", shares);
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if (_main_loop_wait) {
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main_loop_wake();
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}
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}
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}
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public:
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explicit background_reclaimer(scheduling_group sg, noncopyable_function<void (size_t target)> reclaim)
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: _sg(sg)
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, _reclaim(std::move(reclaim))
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, _adjust_shares_timer(default_scheduling_group(), [this] { adjust_shares(); })
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, _done(with_scheduling_group(_sg, [this] { return main_loop(); })) {
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if (sg != default_scheduling_group()) {
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_adjust_shares_timer.arm_periodic(50ms);
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}
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}
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future<> stop() {
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_stopping = true;
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main_loop_wake();
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return std::move(_done);
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}
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};
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class tracker::impl {
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std::optional<background_reclaimer> _background_reclaimer;
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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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future<> stop() {
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if (_background_reclaimer) {
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return _background_reclaimer->stop();
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} else {
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return make_ready_future<>();
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}
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}
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void register_region(region::impl*);
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void unregister_region(region::impl*) noexcept;
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size_t reclaim(size_t bytes, is_preemptible p);
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// Compacts one segment at a time from sparsest segment to least sparse until work_waiting_on_reactor returns true
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// or there are no more segments to compact.
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idle_cpu_handler_result compact_on_idle(work_waiting_on_reactor check_for_work);
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// Releases whole segments back to the segment pool.
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// After the call, if there is enough evictable memory, the amount of free segments in the pool
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|
// will be at least reserve_segments + div_ceil(bytes, segment::size).
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// Returns the amount by which segment_pool.total_memory_in_use() has decreased.
|
|
size_t compact_and_evict(size_t reserve_segments, size_t bytes, is_preemptible p);
|
|
void full_compaction();
|
|
void reclaim_all_free_segments();
|
|
occupancy_stats region_occupancy();
|
|
occupancy_stats occupancy();
|
|
size_t non_lsa_used_space();
|
|
// Set the minimum number of segments reclaimed during single reclamation cycle.
|
|
void set_reclamation_step(size_t step_in_segments) { _reclamation_step = step_in_segments; }
|
|
size_t reclamation_step() const { return _reclamation_step; }
|
|
// Abort on allocation failure from LSA
|
|
void enable_abort_on_bad_alloc() { _abort_on_bad_alloc = true; }
|
|
bool should_abort_on_bad_alloc() const { return _abort_on_bad_alloc; }
|
|
void setup_background_reclaim(scheduling_group sg) {
|
|
assert(!_background_reclaimer);
|
|
_background_reclaimer.emplace(sg, [this] (size_t target) {
|
|
reclaim(target, is_preemptible::yes);
|
|
});
|
|
}
|
|
private:
|
|
// Like compact_and_evict() but assumes that reclaim_lock is held around the operation.
|
|
size_t compact_and_evict_locked(size_t reserve_segments, size_t bytes, is_preemptible preempt);
|
|
// Like reclaim() but assumes that reclaim_lock is held around the operation.
|
|
size_t reclaim_locked(size_t bytes, is_preemptible p);
|
|
};
|
|
|
|
class tracker_reclaimer_lock {
|
|
tracker::impl::reclaiming_lock _lock;
|
|
public:
|
|
tracker_reclaimer_lock() : _lock(shard_tracker().get_impl()) { }
|
|
};
|
|
|
|
tracker::tracker()
|
|
: _impl(std::make_unique<impl>())
|
|
, _reclaimer([this] (seastar::memory::reclaimer::request r) { return reclaim(r); }, memory::reclaimer_scope::sync)
|
|
{ }
|
|
|
|
tracker::~tracker() {
|
|
}
|
|
|
|
future<>
|
|
tracker::stop() {
|
|
return _impl->stop();
|
|
}
|
|
|
|
size_t tracker::reclaim(size_t bytes) {
|
|
return _impl->reclaim(bytes, is_preemptible::no);
|
|
}
|
|
|
|
occupancy_stats tracker::region_occupancy() {
|
|
return _impl->region_occupancy();
|
|
}
|
|
|
|
occupancy_stats tracker::occupancy() {
|
|
return _impl->occupancy();
|
|
}
|
|
|
|
size_t tracker::non_lsa_used_space() const {
|
|
return _impl->non_lsa_used_space();
|
|
}
|
|
|
|
void tracker::full_compaction() {
|
|
return _impl->full_compaction();
|
|
}
|
|
|
|
void tracker::reclaim_all_free_segments() {
|
|
return _impl->reclaim_all_free_segments();
|
|
}
|
|
|
|
tracker& shard_tracker() {
|
|
return tracker_instance;
|
|
}
|
|
|
|
struct alignas(segment_size) segment {
|
|
static constexpr int size_shift = segment_size_shift;
|
|
static constexpr int size_mask = segment_size | (segment_size - 1);
|
|
using size_type = std::conditional_t<(size_shift < 16), uint16_t, uint32_t>;
|
|
static constexpr size_t size = segment_size;
|
|
|
|
uint8_t data[size];
|
|
|
|
segment() noexcept { }
|
|
|
|
template<typename T = void>
|
|
const T* at(size_t offset) const {
|
|
return reinterpret_cast<const T*>(data + offset);
|
|
}
|
|
|
|
template<typename T = void>
|
|
T* at(size_t offset) {
|
|
return reinterpret_cast<T*>(data + offset);
|
|
}
|
|
|
|
bool is_empty();
|
|
void record_alloc(size_type size);
|
|
void record_free(size_type size);
|
|
occupancy_stats occupancy();
|
|
|
|
static void* operator new(size_t size) = delete;
|
|
static void* operator new(size_t, void* ptr) noexcept { return ptr; }
|
|
static void operator delete(void* ptr) = delete;
|
|
};
|
|
|
|
static constexpr size_t max_managed_object_size = segment_size * 0.1;
|
|
static constexpr auto max_used_space_ratio_for_compaction = 0.85;
|
|
static constexpr size_t max_used_space_for_compaction = segment_size * max_used_space_ratio_for_compaction;
|
|
static constexpr size_t min_free_space_for_compaction = segment_size - max_used_space_for_compaction;
|
|
|
|
static_assert(min_free_space_for_compaction >= max_managed_object_size,
|
|
"Segments which cannot fit max_managed_object_size must not be considered compactible for the sake of forward progress of compaction");
|
|
|
|
// Since we only compact if there's >= min_free_space_for_compaction of free space,
|
|
// we use min_free_space_for_compaction as the histogram's minimum size and put
|
|
// everything below that value in the same bucket.
|
|
extern constexpr log_heap_options segment_descriptor_hist_options(min_free_space_for_compaction, 3, segment_size);
|
|
|
|
enum segment_kind : int {
|
|
regular = 0, // Holds objects allocated with region_impl::alloc_small()
|
|
bufs = 1 // Holds objects allocated with region_impl::alloc_buf()
|
|
};
|
|
|
|
struct segment_descriptor : public log_heap_hook<segment_descriptor_hist_options> {
|
|
static constexpr segment::size_type free_space_mask = segment::size_mask;
|
|
static constexpr unsigned bits_for_free_space = segment::size_shift + 1;
|
|
static constexpr segment::size_type segment_kind_mask = 1 << bits_for_free_space;
|
|
static constexpr unsigned bits_for_segment_kind = 1;
|
|
static constexpr unsigned shift_for_segment_kind = bits_for_free_space;
|
|
static_assert(sizeof(segment::size_type) * 8 >= bits_for_free_space + bits_for_segment_kind);
|
|
|
|
segment::size_type _free_space;
|
|
region::impl* _region;
|
|
|
|
segment::size_type free_space() const {
|
|
return _free_space & free_space_mask;
|
|
}
|
|
|
|
void set_free_space(segment::size_type free_space) {
|
|
_free_space = (_free_space & ~free_space_mask) | free_space;
|
|
}
|
|
|
|
segment_kind kind() const {
|
|
return static_cast<segment_kind>((_free_space & segment_kind_mask) >> shift_for_segment_kind);
|
|
}
|
|
|
|
void set_kind(segment_kind kind) {
|
|
_free_space = (_free_space & ~segment_kind_mask)
|
|
| static_cast<segment::size_type>(kind) << shift_for_segment_kind;
|
|
}
|
|
|
|
// Valid if kind() == segment_kind::bufs.
|
|
//
|
|
// _buf_pointers holds links to lsa_buffer objects (paired with lsa_buffer::_link)
|
|
// of live objects in the segment. The purpose of this is so that segment compaction
|
|
// can update the pointers when it moves the objects.
|
|
// The order of entangled objects in the vector is irrelevant.
|
|
// Also, not all entangled objects may be engaged.
|
|
std::vector<entangled> _buf_pointers;
|
|
|
|
segment_descriptor()
|
|
: _region(nullptr)
|
|
{ }
|
|
|
|
bool is_empty() const {
|
|
return free_space() == segment::size;
|
|
}
|
|
|
|
occupancy_stats occupancy() const {
|
|
return { free_space(), segment::size };
|
|
}
|
|
|
|
void record_alloc(segment::size_type size) {
|
|
_free_space -= size;
|
|
}
|
|
|
|
void record_free(segment::size_type size) {
|
|
_free_space += size;
|
|
}
|
|
};
|
|
|
|
using segment_descriptor_hist = log_heap<segment_descriptor, segment_descriptor_hist_options>;
|
|
|
|
#ifndef SEASTAR_DEFAULT_ALLOCATOR
|
|
class segment_store {
|
|
memory::memory_layout _layout;
|
|
uintptr_t _segments_base; // The address of the first segment
|
|
|
|
public:
|
|
size_t non_lsa_reserve = 0;
|
|
segment_store()
|
|
: _layout(memory::get_memory_layout())
|
|
, _segments_base(align_down(_layout.start, (uintptr_t)segment::size)) {
|
|
}
|
|
segment* segment_from_idx(size_t idx) const {
|
|
return reinterpret_cast<segment*>(_segments_base) + idx;
|
|
}
|
|
size_t idx_from_segment(segment* seg) const {
|
|
return seg - reinterpret_cast<segment*>(_segments_base);
|
|
}
|
|
size_t new_idx_for_segment(segment* seg) {
|
|
return idx_from_segment(seg);
|
|
}
|
|
void free_segment(segment *seg) { }
|
|
size_t max_segments() const {
|
|
return (_layout.end - _segments_base) / segment::size;
|
|
}
|
|
bool can_allocate_more_segments() {
|
|
return memory::stats().free_memory() >= non_lsa_reserve + segment::size;
|
|
}
|
|
};
|
|
#else
|
|
class segment_store {
|
|
std::vector<segment*> _segments;
|
|
std::unordered_map<segment*, size_t> _segment_indexes;
|
|
static constexpr size_t _std_memory_available = size_t(1) << 30; // emulate 1GB per shard
|
|
std::vector<segment*>::iterator find_empty() {
|
|
// segment 0 is a marker for no segment
|
|
return std::find(_segments.begin() + 1, _segments.end(), nullptr);
|
|
}
|
|
|
|
public:
|
|
size_t non_lsa_reserve = 0;
|
|
segment_store() : _segments(max_segments()) {
|
|
_segment_indexes.reserve(max_segments());
|
|
}
|
|
segment* segment_from_idx(size_t idx) const {
|
|
assert(idx < _segments.size());
|
|
return _segments[idx];
|
|
}
|
|
size_t idx_from_segment(segment* seg) {
|
|
// segment 0 is a marker for no segment
|
|
auto i = _segment_indexes.find(seg);
|
|
if (i == _segment_indexes.end()) {
|
|
return 0;
|
|
}
|
|
return i->second;
|
|
}
|
|
size_t new_idx_for_segment(segment* seg) {
|
|
auto i = find_empty();
|
|
assert(i != _segments.end());
|
|
*i = seg;
|
|
size_t ret = i - _segments.begin();
|
|
_segment_indexes[seg] = ret;
|
|
return ret;
|
|
}
|
|
void free_segment(segment *seg) {
|
|
size_t i = idx_from_segment(seg);
|
|
assert(i != 0);
|
|
_segment_indexes.erase(seg);
|
|
_segments[i] = nullptr;
|
|
}
|
|
~segment_store() {
|
|
for (segment *seg : _segments) {
|
|
if (seg) {
|
|
seg->~segment();
|
|
free(seg);
|
|
}
|
|
}
|
|
}
|
|
size_t max_segments() const {
|
|
return _std_memory_available / segment::size;
|
|
}
|
|
bool can_allocate_more_segments() {
|
|
auto i = find_empty();
|
|
return i != _segments.end();
|
|
}
|
|
};
|
|
#endif
|
|
|
|
// Segment pool implementation for the seastar allocator.
|
|
// Stores segment descriptors in a vector which is indexed using most significant
|
|
// bits of segment address.
|
|
//
|
|
// We prefer using high-address segments, and returning low-address segments to the seastar
|
|
// allocator in order to segregate lsa and non-lsa memory, to reduce fragmentation.
|
|
class segment_pool {
|
|
segment_store _store;
|
|
std::vector<segment_descriptor> _segments;
|
|
size_t _segments_in_use{};
|
|
utils::dynamic_bitset _lsa_owned_segments_bitmap; // owned by this
|
|
utils::dynamic_bitset _lsa_free_segments_bitmap; // owned by this, but not in use
|
|
size_t _free_segments = 0;
|
|
size_t _current_emergency_reserve_goal = 1;
|
|
size_t _emergency_reserve_max = 30;
|
|
bool _allocation_failure_flag = false;
|
|
bool _allocation_enabled = true;
|
|
|
|
struct allocation_lock {
|
|
segment_pool& _pool;
|
|
bool _prev;
|
|
allocation_lock(segment_pool& p)
|
|
: _pool(p)
|
|
, _prev(p._allocation_enabled)
|
|
{
|
|
_pool._allocation_enabled = false;
|
|
}
|
|
~allocation_lock() {
|
|
_pool._allocation_enabled = _prev;
|
|
}
|
|
};
|
|
|
|
size_t _non_lsa_memory_in_use = 0;
|
|
// Invariants - a segment is in one of the following states:
|
|
// In use by some region
|
|
// - set in _lsa_owned_segments_bitmap
|
|
// - clear in _lsa_free_segments_bitmap
|
|
// - counted in _segments_in_use
|
|
// Free:
|
|
// - set in _lsa_owned_segments_bitmap
|
|
// - set in _lsa_free_segments_bitmap
|
|
// - counted in _unreserved_free_segments
|
|
// Non-lsa:
|
|
// - clear everywhere
|
|
private:
|
|
segment* allocate_segment(size_t reserve);
|
|
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;
|
|
segment* segment_from_idx(size_t idx) const {
|
|
return _store.segment_from_idx(idx);
|
|
}
|
|
size_t idx_from_segment(segment* seg) {
|
|
return _store.idx_from_segment(seg);
|
|
}
|
|
size_t max_segments() const {
|
|
return _store.max_segments();
|
|
}
|
|
bool can_allocate_more_segments() {
|
|
return _allocation_enabled && _store.can_allocate_more_segments();
|
|
}
|
|
bool compact_segment(segment* seg);
|
|
public:
|
|
segment_pool();
|
|
void prime(size_t available_memory, size_t min_free_memory);
|
|
segment* new_segment(region::impl* r);
|
|
segment_descriptor& descriptor(segment*);
|
|
// Returns segment containing given object or nullptr.
|
|
segment* containing_segment(const void* obj);
|
|
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();
|
|
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;
|
|
}
|
|
size_t total_free_memory() const {
|
|
return _free_segments * segment::size;
|
|
}
|
|
struct reservation_goal;
|
|
void set_region(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, is_preemptible preempt);
|
|
void reclaim_all_free_segments() {
|
|
reclaim_segments(std::numeric_limits<size_t>::max(), is_preemptible::no);
|
|
}
|
|
|
|
struct stats {
|
|
size_t segments_compacted;
|
|
size_t lsa_buffer_segments;
|
|
uint64_t memory_allocated;
|
|
uint64_t memory_freed;
|
|
uint64_t memory_compacted;
|
|
uint64_t memory_evicted;
|
|
};
|
|
private:
|
|
stats _stats{};
|
|
public:
|
|
const stats& statistics() const { return _stats; }
|
|
void on_segment_compaction(size_t used_size);
|
|
void on_memory_allocation(size_t size);
|
|
void on_memory_deallocation(size_t size);
|
|
void on_memory_eviction(size_t size);
|
|
size_t unreserved_free_segments() const { return _free_segments - std::min(_free_segments, _emergency_reserve_max); }
|
|
size_t free_segments() const { return _free_segments; }
|
|
};
|
|
|
|
size_t segment_pool::reclaim_segments(size_t target, is_preemptible preempt) {
|
|
// Reclaimer tries to release segments occupying lower parts of the address
|
|
// space.
|
|
|
|
llogger.debug("Trying to reclaim {} segments", target);
|
|
|
|
// Reclamation. Migrate segments to higher addresses and shrink segment pool.
|
|
size_t reclaimed_segments = 0;
|
|
|
|
// We may fail to reclaim because a region has reclaim disabled (usually because
|
|
// it is in an allocating_section. Failed reclaims can cause high CPU usage
|
|
// if all of the lower addresses happen to be in a reclaim-disabled region (this
|
|
// is somewhat mitigated by the fact that checking for reclaim disabled is very
|
|
// cheap), but worse, failing a segment reclaim can lead to reclaimed memory
|
|
// being fragmented. This results in the original allocation continuing to fail.
|
|
//
|
|
// To combat that, we limit the number of failed reclaims. If we reach the limit,
|
|
// we fail the reclaim. The surrounding allocating_section will release the
|
|
// reclaim_lock, and increase reserves, which will result in reclaim being
|
|
// retried with all regions being reclaimable, and succeed in allocating
|
|
// contiguous memory.
|
|
size_t failed_reclaims_allowance = 10;
|
|
|
|
for (size_t src_idx = _lsa_owned_segments_bitmap.find_first_set();
|
|
reclaimed_segments != target && src_idx != utils::dynamic_bitset::npos
|
|
&& _free_segments > _current_emergency_reserve_goal;
|
|
src_idx = _lsa_owned_segments_bitmap.find_next_set(src_idx)) {
|
|
auto src = segment_from_idx(src_idx);
|
|
if (!_lsa_free_segments_bitmap.test(src_idx)) {
|
|
if (!compact_segment(src)) {
|
|
if (--failed_reclaims_allowance == 0) {
|
|
break;
|
|
}
|
|
continue;
|
|
}
|
|
}
|
|
_lsa_free_segments_bitmap.clear(src_idx);
|
|
_lsa_owned_segments_bitmap.clear(src_idx);
|
|
_store.free_segment(src);
|
|
src->~segment();
|
|
::free(src);
|
|
++reclaimed_segments;
|
|
--_free_segments;
|
|
if (preempt && need_preempt()) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
llogger.debug("Reclaimed {} segments (requested {})", reclaimed_segments, target);
|
|
return reclaimed_segments;
|
|
}
|
|
|
|
segment* segment_pool::allocate_segment(size_t reserve)
|
|
{
|
|
//
|
|
// When allocating a segment we want to avoid:
|
|
// - 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 an lsa-owned but free segment
|
|
// 2. If no free segmented is available, a new segment is allocated from the
|
|
// system allocator. 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.
|
|
//
|
|
do {
|
|
tracker_reclaimer_lock rl;
|
|
if (_free_segments > reserve) {
|
|
auto free_idx = _lsa_free_segments_bitmap.find_last_set();
|
|
_lsa_free_segments_bitmap.clear(free_idx);
|
|
auto seg = segment_from_idx(free_idx);
|
|
--_free_segments;
|
|
return seg;
|
|
}
|
|
if (can_allocate_more_segments()) {
|
|
memory::disable_abort_on_alloc_failure_temporarily dfg;
|
|
auto p = aligned_alloc(segment::size, segment::size);
|
|
if (!p) {
|
|
continue;
|
|
}
|
|
auto seg = new (p) segment;
|
|
poison(seg, sizeof(segment));
|
|
auto idx = _store.new_idx_for_segment(seg);
|
|
_lsa_owned_segments_bitmap.set(idx);
|
|
return seg;
|
|
}
|
|
} while (shard_tracker().get_impl().compact_and_evict(reserve, shard_tracker().reclamation_step() * segment::size, is_preemptible::no));
|
|
return nullptr;
|
|
}
|
|
|
|
void segment_pool::deallocate_segment(segment* seg)
|
|
{
|
|
assert(_lsa_owned_segments_bitmap.test(idx_from_segment(seg)));
|
|
_lsa_free_segments_bitmap.set(idx_from_segment(seg));
|
|
_free_segments++;
|
|
}
|
|
|
|
void segment_pool::refill_emergency_reserve() {
|
|
while (_free_segments < _emergency_reserve_max) {
|
|
auto seg = allocate_segment(_emergency_reserve_max);
|
|
if (!seg) {
|
|
throw std::bad_alloc();
|
|
}
|
|
++_segments_in_use;
|
|
free_segment(seg);
|
|
}
|
|
}
|
|
|
|
segment_descriptor&
|
|
segment_pool::descriptor(segment* seg) {
|
|
uintptr_t index = idx_from_segment(seg);
|
|
return _segments[index];
|
|
}
|
|
|
|
segment*
|
|
segment_pool::containing_segment(const void* obj) {
|
|
auto addr = reinterpret_cast<uintptr_t>(obj);
|
|
auto offset = addr & (segment::size - 1);
|
|
auto seg = reinterpret_cast<segment*>(addr - offset);
|
|
auto index = idx_from_segment(seg);
|
|
auto& desc = _segments[index];
|
|
if (desc._region) {
|
|
return seg;
|
|
} else {
|
|
return nullptr;
|
|
}
|
|
}
|
|
|
|
segment*
|
|
segment_pool::segment_from(const segment_descriptor& desc) {
|
|
assert(desc._region);
|
|
auto index = &desc - &_segments[0];
|
|
return segment_from_idx(index);
|
|
}
|
|
|
|
segment*
|
|
segment_pool::allocate_or_fallback_to_reserve() {
|
|
auto seg = allocate_segment(_current_emergency_reserve_goal);
|
|
if (!seg) {
|
|
_allocation_failure_flag = true;
|
|
throw std::bad_alloc();
|
|
}
|
|
return 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.set_free_space(segment::size);
|
|
desc.set_kind(segment_kind::regular);
|
|
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 {}", fmt::ptr(seg));
|
|
desc._region = nullptr;
|
|
deallocate_segment(seg);
|
|
--_segments_in_use;
|
|
}
|
|
|
|
segment_pool::segment_pool()
|
|
: _segments(max_segments())
|
|
, _lsa_owned_segments_bitmap(max_segments())
|
|
, _lsa_free_segments_bitmap(max_segments())
|
|
{
|
|
}
|
|
|
|
void segment_pool::prime(size_t available_memory, size_t min_free_memory) {
|
|
auto old_emergency_reserve = std::exchange(_emergency_reserve_max, std::numeric_limits<size_t>::max());
|
|
try {
|
|
// Allocate all of memory so that we occupy the top part. Afterwards, we'll start
|
|
// freeing from the bottom.
|
|
_store.non_lsa_reserve = 0;
|
|
refill_emergency_reserve();
|
|
} catch (std::bad_alloc&) {
|
|
_emergency_reserve_max = old_emergency_reserve;
|
|
}
|
|
// We want to leave more free memory than just min_free_memory() in order to reduce
|
|
// the frequency of expensive segment-migrating reclaim() called by the seastar allocator.
|
|
size_t min_gap = 1 * 1024 * 1024;
|
|
size_t max_gap = 32 * 1024 * 1024;
|
|
size_t gap = std::min(max_gap, std::max(available_memory / 16, min_gap));
|
|
_store.non_lsa_reserve = min_free_memory + gap;
|
|
// Since the reclaimer is not yet in place, free some low memory for general use
|
|
reclaim_segments(_store.non_lsa_reserve / segment::size, is_preemptible::no);
|
|
}
|
|
|
|
void segment_pool::on_segment_compaction(size_t used_size) {
|
|
_stats.segments_compacted++;
|
|
_stats.memory_compacted += used_size;
|
|
}
|
|
|
|
void segment_pool::on_memory_allocation(size_t size) {
|
|
_stats.memory_allocated += size;
|
|
}
|
|
|
|
void segment_pool::on_memory_deallocation(size_t size) {
|
|
_stats.memory_freed += size;
|
|
}
|
|
|
|
void segment_pool::on_memory_eviction(size_t size) {
|
|
_stats.memory_evicted += size;
|
|
}
|
|
|
|
// 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 segment_pool& get_shard_segment_pool() noexcept {
|
|
memory::scoped_critical_alloc_section dfg;
|
|
static thread_local segment_pool obj;
|
|
return obj;
|
|
}
|
|
|
|
static thread_local segment_pool& shard_segment_pool = get_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() {
|
|
return shard_segment_pool.descriptor(this).is_empty();
|
|
}
|
|
|
|
occupancy_stats
|
|
segment::occupancy() {
|
|
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 utils::uleb64_encoded_size(_n); // 0 is illegal
|
|
}
|
|
|
|
void encode(char*& pos) const {
|
|
utils::uleb64_encode(pos, _n, poison<char>, unpoison);
|
|
}
|
|
|
|
// non-canonical encoding to allow padding (for alignment); encoded_size must be
|
|
// sufficient (greater than this->encoded_size()), _n must be the migrator's
|
|
// index() (i.e. -- suitable for express encoding)
|
|
void encode(char*& pos, size_t encoded_size, size_t size) const {
|
|
utils::uleb64_express_encode(pos, _n, encoded_size, size, poison<char>, unpoison);
|
|
}
|
|
|
|
static object_descriptor decode_forwards(const char*& pos) {
|
|
return object_descriptor(utils::uleb64_decode_forwards(pos, poison<char>, unpoison));
|
|
}
|
|
|
|
static object_descriptor decode_backwards(const char*& pos) {
|
|
return object_descriptor(utils::uleb64_decode_bacwards(pos, poison<char>, unpoison));
|
|
}
|
|
|
|
friend std::ostream& operator<<(std::ostream& out, const object_descriptor& desc) {
|
|
if (!desc.is_live()) {
|
|
return out << format("{{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 << format("{{migrator={:p}, alignment={:d}, size={:d}}}",
|
|
(void*)m, m->align(), m->size(obj));
|
|
}
|
|
}
|
|
};
|
|
private: // lsa_buffer allocator
|
|
segment* _buf_active = nullptr;
|
|
size_t _buf_active_offset;
|
|
static constexpr size_t buf_align = 4096; // All lsa_buffer:s will have addresses aligned to this value.
|
|
// Emergency storage to ensure forward progress during segment compaction,
|
|
// by ensuring that _buf_pointers allocation inside new_buf_active() does not fail.
|
|
std::vector<entangled> _buf_ptrs_for_compact_segment;
|
|
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;
|
|
// This is a mask applied to _evictable_space with bitwise-and before it's returned from evictable_space().
|
|
// Used for forcing the result to zero without using conditionals.
|
|
size_t _evictable_space_mask = std::numeric_limits<size_t>::max();
|
|
bool _evictable = false;
|
|
region_sanitizer _sanitizer;
|
|
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(const object_descriptor& desc, segment::size_type size, size_t alignment) {
|
|
if (!_active) {
|
|
_active = new_segment();
|
|
_active_offset = 0;
|
|
}
|
|
|
|
auto desc_encoded_size = desc.encoded_size();
|
|
|
|
size_t obj_offset = align_up_for_asan(align_up(_active_offset + desc_encoded_size, alignment));
|
|
if (obj_offset + size > segment::size) {
|
|
close_and_open();
|
|
return alloc_small(desc, 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, size);
|
|
unpoison(pos, size);
|
|
_active_offset = obj_offset + size;
|
|
|
|
// Align the end of the value so that the next descriptor is aligned
|
|
_active_offset = align_up_for_asan(_active_offset);
|
|
_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*, size_t)>>::value, "bad Func signature");
|
|
|
|
auto pos = align_up_for_asan(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), size);
|
|
pos += size;
|
|
} else {
|
|
pos = old_pos + desc.dead_size();
|
|
}
|
|
pos = align_up_for_asan(pos);
|
|
}
|
|
}
|
|
|
|
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]", fmt::ptr(_active), _active->occupancy(), segment::size - _active_offset);
|
|
_closed_occupancy += _active->occupancy();
|
|
|
|
_segment_descs.push(shard_segment_pool.descriptor(_active));
|
|
_active = nullptr;
|
|
}
|
|
|
|
void close_buf_active() {
|
|
if (!_buf_active) {
|
|
return;
|
|
}
|
|
llogger.trace("Closing buf segment {}, used={}, waste={} [B]", fmt::ptr(_buf_active), _buf_active->occupancy(), segment::size - _buf_active_offset);
|
|
_closed_occupancy += _buf_active->occupancy();
|
|
|
|
_segment_descs.push(shard_segment_pool.descriptor(_buf_active));
|
|
_buf_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;
|
|
}
|
|
|
|
lsa_buffer alloc_buf(size_t buf_size) {
|
|
static_assert(segment::size % buf_align == 0);
|
|
if (buf_size > segment::size) {
|
|
throw_with_backtrace<std::runtime_error>(format("Buffer size {} too large", buf_size));
|
|
}
|
|
|
|
if (_buf_active_offset + buf_size > segment::size) {
|
|
close_buf_active();
|
|
}
|
|
|
|
if (!_buf_active) {
|
|
new_buf_active();
|
|
}
|
|
|
|
lsa_buffer ptr;
|
|
ptr._buf = _buf_active->at<char>(_buf_active_offset);
|
|
ptr._size = buf_size;
|
|
unpoison(ptr._buf, buf_size);
|
|
|
|
segment_descriptor& desc = shard_segment_pool.descriptor(_buf_active);
|
|
ptr._desc = &desc;
|
|
desc._buf_pointers.emplace_back(entangled::make_paired_with(ptr._link));
|
|
auto alloc_size = align_up(buf_size, buf_align);
|
|
desc.record_alloc(alloc_size);
|
|
_buf_active_offset += alloc_size;
|
|
|
|
return ptr;
|
|
}
|
|
|
|
void free_buf(lsa_buffer& buf) noexcept {
|
|
segment_descriptor &desc = *buf._desc;
|
|
segment *seg = shard_segment_pool.segment_from(desc);
|
|
|
|
if (seg != _buf_active) {
|
|
_closed_occupancy -= seg->occupancy();
|
|
}
|
|
|
|
auto alloc_size = align_up(buf._size, buf_align);
|
|
desc.record_free(alloc_size);
|
|
poison(buf._buf, buf._size);
|
|
|
|
// Pack links so that segment compaction only has to walk live objects.
|
|
// This procedure also ensures that the link for buf is destroyed, either
|
|
// by replacing it with the last entangled, or by popping it from the back
|
|
// if it is the last element.
|
|
// Moving entangled links around is fine so we can move last_link.
|
|
entangled& last_link = desc._buf_pointers.back();
|
|
entangled& buf_link = *buf._link.get();
|
|
std::swap(last_link, buf_link);
|
|
desc._buf_pointers.pop_back();
|
|
|
|
if (seg != _buf_active) {
|
|
if (desc.is_empty()) {
|
|
_segment_descs.erase(desc);
|
|
desc._buf_pointers = std::vector<entangled>();
|
|
free_segment(seg, desc);
|
|
} else {
|
|
_segment_descs.adjust_up(desc);
|
|
_closed_occupancy += desc.occupancy();
|
|
}
|
|
}
|
|
}
|
|
|
|
void compact_segment_locked(segment* seg, segment_descriptor& desc) {
|
|
auto seg_occupancy = desc.occupancy();
|
|
llogger.debug("Compacting segment {} from region {}, {}", fmt::ptr(seg), id(), seg_occupancy);
|
|
|
|
++_invalidate_counter;
|
|
|
|
if (desc.kind() == segment_kind::bufs) {
|
|
// This will free the storage of _buf_ptrs_for_compact_segment
|
|
// making sure that alloc_buf() makes progress.
|
|
// Also, empties desc._buf_pointers, making it back a generic segment, which
|
|
// we need to do before freeing it.
|
|
_buf_ptrs_for_compact_segment = std::move(desc._buf_pointers);
|
|
for (entangled& e : _buf_ptrs_for_compact_segment) {
|
|
if (e) {
|
|
lsa_buffer* old_ptr = e.get(&lsa_buffer::_link);
|
|
lsa_buffer dst = alloc_buf(old_ptr->_size);
|
|
memcpy(dst._buf, old_ptr->_buf, dst._size);
|
|
old_ptr->_link = std::move(dst._link);
|
|
old_ptr->_buf = dst._buf;
|
|
old_ptr->_desc = dst._desc;
|
|
}
|
|
}
|
|
} else {
|
|
for_each_live(seg, [this](const object_descriptor *desc, void *obj, size_t size) {
|
|
auto dst = alloc_small(*desc, size, desc->alignment());
|
|
_sanitizer.on_migrate(obj, size, dst);
|
|
desc->migrator()->migrate(obj, dst, size);
|
|
});
|
|
}
|
|
|
|
free_segment(seg, desc);
|
|
shard_segment_pool.on_segment_compaction(seg_occupancy.used_space());
|
|
}
|
|
|
|
void close_and_open() {
|
|
segment* new_active = new_segment();
|
|
close_active();
|
|
_active = new_active;
|
|
_active_offset = 0;
|
|
}
|
|
|
|
void new_buf_active() {
|
|
std::vector<entangled> ptrs;
|
|
ptrs.reserve(segment::size / buf_align);
|
|
segment* new_active = new_segment();
|
|
assert((uintptr_t)new_active->at(0) % buf_align == 0);
|
|
segment_descriptor& desc = shard_segment_pool.descriptor(new_active);
|
|
desc._buf_pointers = std::move(ptrs);
|
|
desc.set_kind(segment_kind::bufs);
|
|
_buf_active = new_active;
|
|
_buf_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())
|
|
{
|
|
_buf_ptrs_for_compact_segment.reserve(segment::size / buf_align);
|
|
_preferred_max_contiguous_allocation = max_managed_object_size;
|
|
tracker_instance._impl->register_region(this);
|
|
try {
|
|
if (group) {
|
|
group->add(this);
|
|
}
|
|
} catch (...) {
|
|
tracker_instance._impl->unregister_region(this);
|
|
throw;
|
|
}
|
|
}
|
|
|
|
virtual ~region_impl() {
|
|
_sanitizer.on_region_destruction();
|
|
|
|
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 (_buf_active) {
|
|
assert(_buf_active->is_empty());
|
|
free_segment(_buf_active);
|
|
_buf_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();
|
|
}
|
|
if (_buf_active) {
|
|
total += _buf_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(0, _evictable_space & _evictable_space_mask);
|
|
}
|
|
|
|
void ground_evictable_occupancy() {
|
|
_evictable_space_mask = 0;
|
|
if (_group) {
|
|
_group->decrease_evictable_usage(_heap_handle);
|
|
}
|
|
}
|
|
|
|
//
|
|
// 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
|
|
// We require 2 segments per allocation segregation group to ensure forward progress during compaction.
|
|
// There are currently two fixed groups, one for the allocation_strategy implementation and one for lsa_buffer:s.
|
|
&& (_closed_occupancy.free_space() >= 4 * 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();
|
|
shard_segment_pool.on_memory_allocation(size);
|
|
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 {
|
|
auto ptr = alloc_small(object_descriptor(migrator), (segment::size_type) size, alignment);
|
|
_sanitizer.on_allocation(ptr, size);
|
|
return ptr;
|
|
}
|
|
}
|
|
|
|
private:
|
|
void on_non_lsa_free(void* obj) noexcept {
|
|
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);
|
|
}
|
|
public:
|
|
virtual void free(void* obj) noexcept override {
|
|
compaction_lock _(*this);
|
|
segment* seg = shard_segment_pool.containing_segment(obj);
|
|
if (!seg) {
|
|
on_non_lsa_free(obj);
|
|
standard_allocator().free(obj);
|
|
return;
|
|
}
|
|
|
|
auto pos = reinterpret_cast<const char*>(obj);
|
|
auto desc = object_descriptor::decode_backwards(pos);
|
|
free(obj, desc.live_size(obj));
|
|
}
|
|
|
|
virtual void free(void* obj, size_t size) noexcept override {
|
|
compaction_lock _(*this);
|
|
segment* seg = shard_segment_pool.containing_segment(obj);
|
|
|
|
if (!seg) {
|
|
on_non_lsa_free(obj);
|
|
standard_allocator().free(obj, size);
|
|
return;
|
|
}
|
|
|
|
_sanitizer.on_free(obj, size);
|
|
|
|
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 = align_up_for_asan(size + (old_pos - pos));
|
|
desc = object_descriptor::make_dead(dead_size);
|
|
auto npos = const_cast<char*>(pos);
|
|
desc.encode(npos);
|
|
poison(pos, dead_size);
|
|
|
|
if (seg != _active) {
|
|
_closed_occupancy -= seg->occupancy();
|
|
}
|
|
|
|
seg_desc.record_free(dead_size);
|
|
shard_segment_pool.on_memory_deallocation(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 {
|
|
// degroup_temporarily allocates via binomial_heap::push(), which should not
|
|
// fail, because we have a matching deallocation before that and we don't
|
|
// allocate between them.
|
|
memory::scoped_critical_alloc_section dfg;
|
|
|
|
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();
|
|
}
|
|
other.close_buf_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);
|
|
|
|
_sanitizer.merge(other._sanitizer);
|
|
other._sanitizer = { };
|
|
}
|
|
|
|
// Returns occupancy of the sparsest compactible segment.
|
|
occupancy_stats min_occupancy() const {
|
|
if (_segment_descs.empty()) {
|
|
return {};
|
|
}
|
|
return _segment_descs.one_of_largest().occupancy();
|
|
}
|
|
|
|
// Compacts a single segment, most appropriate for it
|
|
void compact() {
|
|
compaction_lock _(*this);
|
|
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);
|
|
compact_segment_locked(seg, desc);
|
|
}
|
|
|
|
// Compacts everything. Mainly for testing.
|
|
// Invalidates references to allocated objects.
|
|
void full_compaction() {
|
|
compaction_lock _(*this);
|
|
llogger.debug("Full compaction, {}", occupancy());
|
|
close_and_open();
|
|
close_buf_active();
|
|
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_segment_locked(shard_segment_pool.segment_from(desc), desc);
|
|
}
|
|
llogger.debug("Done, {}", occupancy());
|
|
}
|
|
|
|
void compact_segment(segment* seg, segment_descriptor& desc) {
|
|
compaction_lock _(*this);
|
|
if (_active == seg) {
|
|
close_active();
|
|
} else if (_buf_active == seg) {
|
|
close_buf_active();
|
|
}
|
|
_segment_descs.erase(desc);
|
|
_closed_occupancy -= desc.occupancy();
|
|
compact_segment_locked(seg, desc);
|
|
}
|
|
|
|
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;
|
|
auto freed = shard_segment_pool.statistics().memory_freed;
|
|
auto ret = _eviction_fn();
|
|
shard_segment_pool.on_memory_eviction(shard_segment_pool.statistics().memory_freed - freed);
|
|
return ret;
|
|
}
|
|
|
|
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 lsa_buffer;
|
|
friend class region_group;
|
|
friend class region_group::region_evictable_occupancy_ascending_less_comparator;
|
|
};
|
|
|
|
lsa_buffer::~lsa_buffer() {
|
|
if (_link) {
|
|
_desc->_region->free_buf(*this);
|
|
}
|
|
}
|
|
|
|
inline void
|
|
region_group_binomial_group_sanity_check(const region_group::region_heap& bh) {
|
|
#ifdef SEASTAR_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
|
|
}
|
|
|
|
size_t tracker::reclamation_step() const {
|
|
return _impl->reclamation_step();
|
|
}
|
|
|
|
bool tracker::should_abort_on_bad_alloc() {
|
|
return _impl->should_abort_on_bad_alloc();
|
|
}
|
|
|
|
void tracker::configure(const config& cfg) {
|
|
if (cfg.defragment_on_idle) {
|
|
engine().set_idle_cpu_handler([this] (reactor::work_waiting_on_reactor check_for_work) {
|
|
return _impl->compact_on_idle(check_for_work);
|
|
});
|
|
}
|
|
|
|
_impl->set_reclamation_step(cfg.lsa_reclamation_step);
|
|
if (cfg.abort_on_lsa_bad_alloc) {
|
|
_impl->enable_abort_on_bad_alloc();
|
|
}
|
|
_impl->setup_background_reclaim(cfg.background_reclaim_sched_group);
|
|
s_sanitizer_report_backtrace = cfg.sanitizer_report_backtrace;
|
|
}
|
|
|
|
memory::reclaiming_result tracker::reclaim(seastar::memory::reclaimer::request r) {
|
|
return reclaim(std::max(r.bytes_to_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();
|
|
}
|
|
|
|
lsa_buffer region::alloc_buf(size_t buffer_size) {
|
|
return get_impl().alloc_buf(buffer_size);
|
|
}
|
|
|
|
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));
|
|
}
|
|
|
|
void region::ground_evictable_occupancy() {
|
|
get_impl().ground_evictable_occupancy();
|
|
}
|
|
|
|
occupancy_stats region::evictable_occupancy() {
|
|
return get_impl().evictable_occupancy();
|
|
}
|
|
|
|
const eviction_fn& region::evictor() const {
|
|
return get_impl().evictor();
|
|
}
|
|
|
|
std::ostream& operator<<(std::ostream& out, const occupancy_stats& stats) {
|
|
return out << format("{:.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() {
|
|
#ifdef SEASTAR_DEFAULT_ALLOCATOR
|
|
return 0;
|
|
#else
|
|
auto free_space_in_lsa = shard_segment_pool.free_segments() * segment_size;
|
|
return memory::stats().allocated_memory() - region_occupancy().total_space() - free_space_in_lsa;
|
|
#endif
|
|
}
|
|
|
|
void tracker::impl::reclaim_all_free_segments()
|
|
{
|
|
llogger.debug("Reclaiming all free segments");
|
|
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, is_preemptible preempt) {
|
|
llogger.debug("reclaim_from_evictable: total_memory_in_use={} target={}", shard_segment_pool.total_memory_in_use(), target_mem_in_use);
|
|
|
|
// Before attempting segment compaction, try to evict at least deficit and one segment more so that
|
|
// for workloads in which eviction order matches allocation order we will reclaim full segments
|
|
// without needing to perform expensive compaction.
|
|
auto deficit = shard_segment_pool.total_memory_in_use() - target_mem_in_use;
|
|
auto used = r.occupancy().used_space();
|
|
auto used_target = used - std::min(used, deficit + segment::size);
|
|
|
|
while (shard_segment_pool.total_memory_in_use() > target_mem_in_use) {
|
|
used = r.occupancy().used_space();
|
|
if (used > used_target) {
|
|
llogger.debug("Evicting {} bytes from region {}, occupancy={} in advance",
|
|
used - used_target, r.id(), r.occupancy());
|
|
} else {
|
|
llogger.debug("Evicting from region {}, occupancy={} until it's compactible", r.id(), r.occupancy());
|
|
}
|
|
while (r.occupancy().used_space() > used_target || !r.is_compactible()) {
|
|
if (r.evict_some() == memory::reclaiming_result::reclaimed_nothing) {
|
|
if (r.is_compactible()) { // Need to make forward progress in case there is nothing to evict.
|
|
break;
|
|
}
|
|
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 (preempt && need_preempt()) {
|
|
llogger.debug("reclaim_from_evictable preempted");
|
|
return;
|
|
}
|
|
}
|
|
// If there are many compactible segments, we will keep compacting without
|
|
// entering the eviction loop above. So the preemption check there is not
|
|
// sufficient and we also need to check here.
|
|
//
|
|
// Note that a preemptible reclaim_from_evictable may not do any real progress,
|
|
// but it doesn't need to. Preemptible (background) reclaim is an optimization.
|
|
// If the system is overwhelmed, and reclaim_from_evictable keeps getting
|
|
// preempted without doing any useful work, then eventually memory will be
|
|
// exhausted and reclaim will be called synchronously, without preemption.
|
|
if (preempt && need_preempt()) {
|
|
llogger.debug("reclaim_from_evictable preempted");
|
|
return;
|
|
}
|
|
llogger.debug("Compacting after evicting {} bytes", used - r.occupancy().used_space());
|
|
r.compact();
|
|
}
|
|
}
|
|
|
|
class reclaim_timer {
|
|
using clock = utils::coarse_steady_clock;
|
|
|
|
const is_preemptible _preemptible;
|
|
const size_t _memory_to_release;
|
|
const size_t _reserve_segments;
|
|
tracker::impl& _tracker;
|
|
|
|
const bool _debug_enabled;
|
|
bool _stall_detected = false;
|
|
|
|
size_t _memory_released = 0;
|
|
|
|
clock::time_point _start;
|
|
clock::duration _duration;
|
|
occupancy_stats _old_region_occupancy;
|
|
segment_pool::stats _old_pool_stats;
|
|
|
|
public:
|
|
reclaim_timer(is_preemptible preemptible, size_t memory_to_release, size_t reserve_segments, tracker::impl& tracker)
|
|
: _preemptible(preemptible)
|
|
, _memory_to_release(memory_to_release)
|
|
, _reserve_segments(reserve_segments)
|
|
, _tracker(tracker)
|
|
, _debug_enabled(timing_logger.is_enabled(logging::log_level::debug))
|
|
{
|
|
_start = clock::now();
|
|
if (_debug_enabled) {
|
|
_old_region_occupancy = tracker.region_occupancy();
|
|
}
|
|
_old_pool_stats = shard_segment_pool.statistics();
|
|
}
|
|
|
|
size_t set_result(size_t memory_released) noexcept {
|
|
return this->_memory_released = memory_released;
|
|
}
|
|
|
|
~reclaim_timer() {
|
|
_duration = clock::now() - _start;
|
|
_stall_detected = _duration >= engine().get_blocked_reactor_notify_ms();
|
|
if (_debug_enabled || _stall_detected) {
|
|
report();
|
|
}
|
|
}
|
|
|
|
private:
|
|
template <typename T>
|
|
void log_if_changed(log_level level, const char* name, T before, T now) const noexcept {
|
|
if (now != before) {
|
|
timing_logger.log(level, "- {}: {:.3f} -> {:.3f}", name, before, now);
|
|
}
|
|
}
|
|
template <typename T>
|
|
void log_if_any(log_level level, const char* name, T value) const noexcept {
|
|
if (value != 0) {
|
|
timing_logger.log(level, "- {}: {}", name, value);
|
|
}
|
|
}
|
|
template <typename T>
|
|
void log_if_any_mem(log_level level, const char* name, T value) const noexcept {
|
|
if (value != 0) {
|
|
timing_logger.log(level, "- {}: {:.3f} MiB", name, (float)value / (1024*1024));
|
|
}
|
|
}
|
|
|
|
void report() const noexcept {
|
|
auto time_level = _stall_detected ? log_level::warn : log_level::debug;
|
|
auto info_level = _stall_detected ? log_level::info : log_level::debug;
|
|
auto MiB = 1024*1024;
|
|
|
|
timing_logger.log(time_level, "Reclamation cycle took {} ms, trying to release {:.3f} MiB {}preemptibly",
|
|
_duration.count(), (float)_memory_to_release / MiB, _preemptible ? "" : "non-");
|
|
log_if_any(info_level, "reserved segments", _reserve_segments);
|
|
if (_memory_released > 0) {
|
|
auto bytes_per_second =
|
|
static_cast<float>(_memory_released) / std::chrono::duration_cast<std::chrono::duration<float>>(_duration).count();
|
|
timing_logger.log(info_level, "- reclamation rate = {} MiB/s", format("{:.3f}", bytes_per_second / MiB));
|
|
}
|
|
if (_debug_enabled) {
|
|
log_if_changed(info_level, "occupancy of regions",
|
|
_old_region_occupancy.used_fraction(), _tracker.region_occupancy().used_fraction());
|
|
}
|
|
|
|
auto pool_stats = shard_segment_pool.statistics();
|
|
log_if_any_mem(info_level, "evicted memory", pool_stats.memory_evicted - _old_pool_stats.memory_evicted);
|
|
log_if_any(info_level, "compacted segments", pool_stats.segments_compacted - _old_pool_stats.segments_compacted);
|
|
log_if_any_mem(info_level, "compacted memory", pool_stats.memory_compacted - _old_pool_stats.memory_compacted);
|
|
log_if_any_mem(info_level, "allocated memory", pool_stats.memory_allocated - _old_pool_stats.memory_allocated);
|
|
}
|
|
};
|
|
|
|
idle_cpu_handler_result tracker::impl::compact_on_idle(work_waiting_on_reactor check_for_work) {
|
|
if (!_reclaiming_enabled) {
|
|
return idle_cpu_handler_result::no_more_work;
|
|
}
|
|
reclaiming_lock rl(*this);
|
|
if (_regions.empty()) {
|
|
return 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 idle_cpu_handler_result::no_more_work;
|
|
}
|
|
|
|
r->compact();
|
|
|
|
boost::range::push_heap(_regions, cmp);
|
|
}
|
|
return idle_cpu_handler_result::interrupted_by_higher_priority_task;
|
|
}
|
|
|
|
size_t tracker::impl::reclaim(size_t memory_to_release, is_preemptible preempt) {
|
|
if (!_reclaiming_enabled) {
|
|
return 0;
|
|
}
|
|
reclaiming_lock rl(*this);
|
|
reclaim_timer timing_guard(preempt, memory_to_release, 0, *this);
|
|
return timing_guard.set_result(reclaim_locked(memory_to_release, preempt));
|
|
}
|
|
|
|
size_t tracker::impl::reclaim_locked(size_t memory_to_release, is_preemptible preempt) {
|
|
// Reclamation steps:
|
|
// 1. Try to release free segments from segment pool and emergency reserve.
|
|
// 2. Compact used segments and/or evict data.
|
|
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, preempt);
|
|
size_t mem_released = nr_released * segment::size;
|
|
if (mem_released >= memory_to_release) {
|
|
return memory_to_release;
|
|
}
|
|
if (preempt && need_preempt()) {
|
|
return mem_released;
|
|
}
|
|
|
|
auto compacted = compact_and_evict_locked(shard_segment_pool.current_emergency_reserve_goal(), memory_to_release - mem_released, preempt);
|
|
|
|
if (compacted == 0) {
|
|
return mem_released;
|
|
}
|
|
|
|
// compact_and_evict_locked() will not return segments to the standard allocator,
|
|
// so do it here:
|
|
nr_released = shard_segment_pool.reclaim_segments(compacted / segment::size, preempt);
|
|
|
|
return mem_released + nr_released * segment::size;
|
|
}
|
|
|
|
size_t tracker::impl::compact_and_evict(size_t reserve_segments, size_t memory_to_release, is_preemptible preempt) {
|
|
if (!_reclaiming_enabled) {
|
|
return 0;
|
|
}
|
|
reclaiming_lock rl(*this);
|
|
reclaim_timer timing_guard(preempt, memory_to_release, reserve_segments, *this);
|
|
return timing_guard.set_result(compact_and_evict_locked(reserve_segments, memory_to_release, preempt));
|
|
}
|
|
|
|
size_t tracker::impl::compact_and_evict_locked(size_t reserve_segments, size_t memory_to_release, is_preemptible preempt) {
|
|
//
|
|
// 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 mem_in_use = shard_segment_pool.total_memory_in_use();
|
|
memory_to_release += (reserve_segments - std::min(reserve_segments, shard_segment_pool.free_segments())) * segment::size;
|
|
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;
|
|
}
|
|
|
|
// Prefer evicting if average occupancy ratio is above the compaction threshold to avoid
|
|
// overhead of compaction in workloads where allocation order matches eviction order, where
|
|
// we can reclaim memory by eviction only. In some cases the cost of compaction on allocation
|
|
// would be higher than the cost of repopulating the region with evicted items.
|
|
if (r->is_evictable() && r->occupancy().used_space() >= max_used_space_ratio_for_compaction * r->occupancy().total_space()) {
|
|
reclaim_from_evictable(*r, target_mem, preempt);
|
|
} else {
|
|
r->compact();
|
|
}
|
|
|
|
boost::range::push_heap(_regions, cmp);
|
|
|
|
if (preempt && need_preempt()) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
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 (preempt && need_preempt()) {
|
|
break;
|
|
}
|
|
if (r->is_evictable()) {
|
|
reclaim_from_evictable(*r, target_mem, preempt);
|
|
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",
|
|
mem_released, memory_to_release, released_during_compaction);
|
|
|
|
return mem_released;
|
|
}
|
|
|
|
void tracker::impl::register_region(region::impl* r) {
|
|
// If needed, increase capacity of regions before taking the reclaim lock,
|
|
// to avoid failing an allocation when push_back() tries to increase
|
|
// capacity.
|
|
//
|
|
// The capacity increase is atomic (wrt _regions) so it cannot be
|
|
// observed
|
|
if (_regions.size() == _regions.capacity()) {
|
|
auto copy = _regions;
|
|
copy.reserve(copy.capacity() * 2);
|
|
_regions = std::move(copy);
|
|
}
|
|
reclaiming_lock _(*this);
|
|
_regions.push_back(r);
|
|
llogger.debug("Registered region @{} with id={}", fmt::ptr(r), r->id());
|
|
}
|
|
|
|
void tracker::impl::unregister_region(region::impl* r) noexcept {
|
|
reclaiming_lock _(*this);
|
|
llogger.debug("Unregistering region, id={}", r->id());
|
|
_regions.erase(std::remove(_regions.begin(), _regions.end(), r), _regions.end());
|
|
}
|
|
|
|
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", [] { 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", [] { return shard_segment_pool.unreserved_free_segments() * segment_size; },
|
|
sm::description("Holds a current amount of free memory that is under lsa control.")),
|
|
|
|
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_derive("segments_compacted", [] { return shard_segment_pool.statistics().segments_compacted; },
|
|
sm::description("Counts a number of compacted segments.")),
|
|
|
|
sm::make_derive("memory_compacted", [] { return shard_segment_pool.statistics().memory_compacted; },
|
|
sm::description("Counts number of bytes which were copied as part of segment compaction.")),
|
|
|
|
sm::make_derive("memory_allocated", [] { return shard_segment_pool.statistics().memory_allocated; },
|
|
sm::description("Counts number of bytes which were requested from LSA.")),
|
|
|
|
sm::make_derive("memory_evicted", [] { return shard_segment_pool.statistics().memory_evicted; },
|
|
sm::description("Counts number of bytes which were evicted.")),
|
|
|
|
sm::make_derive("memory_freed", [] { return shard_segment_pool.statistics().memory_freed; },
|
|
sm::description("Counts number of bytes which were requested to be freed in LSA.")),
|
|
});
|
|
}
|
|
|
|
tracker::impl::~impl() {
|
|
if (!_regions.empty()) {
|
|
for (auto&& r : _regions) {
|
|
llogger.error("Region with id={} not unregistered!", r->id());
|
|
}
|
|
abort();
|
|
}
|
|
}
|
|
|
|
bool segment_pool::compact_segment(segment* seg) {
|
|
auto& desc = descriptor(seg);
|
|
if (!desc._region->reclaiming_enabled()) {
|
|
return false;
|
|
}
|
|
|
|
// Called with emergency reserve, open one for
|
|
// region::alloc_small not to throw if it needs
|
|
// one more segment
|
|
reservation_goal open_emergency_pool(*this, 0);
|
|
allocation_lock no_alloc(*this);
|
|
tracker_reclaimer_lock no_reclaim;
|
|
|
|
desc._region->compact_segment(seg, desc);
|
|
return true;
|
|
}
|
|
|
|
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(scheduling_group deferred_work_sg) {
|
|
return with_scheduling_group(deferred_work_sg, [this] {
|
|
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(sstring name, region_group *parent,
|
|
region_group_reclaimer& reclaimer, scheduling_group deferred_work_sg)
|
|
: _parent(parent)
|
|
, _reclaimer(reclaimer)
|
|
, _blocked_requests(on_request_expiry{std::move(name)})
|
|
, _releaser(reclaimer_can_block() ? start_releaser(deferred_work_sg) : 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);
|
|
}
|
|
|
|
void allocating_section::maybe_decay_reserve() {
|
|
// The decay rate is inversely proportional to the reserve
|
|
// (every (s_segments_per_decay/_lsa_reserve) allocations).
|
|
//
|
|
// If the reserve is high, it is expensive since we may need to
|
|
// evict a lot of memory to satisfy the reserve. Hence, we are
|
|
// willing to risk a more frequent bad_alloc in order to decay it.
|
|
// The cost of a bad_alloc is also lower compared to maintaining
|
|
// the reserve.
|
|
//
|
|
// If the reserve is low, it is not expensive to maintain, so we
|
|
// decay it at a lower rate.
|
|
|
|
_remaining_lsa_segments_until_decay -= _lsa_reserve;
|
|
if (_remaining_lsa_segments_until_decay < 0) {
|
|
_remaining_lsa_segments_until_decay = s_segments_per_decay;
|
|
_lsa_reserve = std::max(s_min_lsa_reserve, _lsa_reserve / 2);
|
|
llogger.debug("Decaying LSA reserve in section {} to {} segments", static_cast<void*>(this), _lsa_reserve);
|
|
}
|
|
|
|
_remaining_std_bytes_until_decay -= _std_reserve;
|
|
if (_remaining_std_bytes_until_decay < 0) {
|
|
_remaining_std_bytes_until_decay = s_bytes_per_decay;
|
|
_std_reserve = std::max(s_min_std_reserve, _std_reserve / 2);
|
|
llogger.debug("Decaying standard allocator head-room in section {} to {} [B]", static_cast<void*>(this), _std_reserve);
|
|
}
|
|
}
|
|
|
|
void allocating_section::reserve() {
|
|
try {
|
|
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();
|
|
} catch (const std::bad_alloc&) {
|
|
if (shard_tracker().should_abort_on_bad_alloc()) {
|
|
llogger.error("Aborting due to allocation failure");
|
|
abort();
|
|
}
|
|
throw;
|
|
}
|
|
}
|
|
|
|
void allocating_section::on_alloc_failure(logalloc::region& r) {
|
|
r.allocator().invalidate_references();
|
|
if (shard_segment_pool.allocation_failure_flag()) {
|
|
_lsa_reserve *= 2;
|
|
llogger.debug("LSA allocation failure, increasing reserve in section {} to {} segments", fmt::ptr(this), _lsa_reserve);
|
|
} else {
|
|
_std_reserve *= 2;
|
|
llogger.debug("Standard allocator failure, increasing head-room in section {} to {} [B]", fmt::ptr(this), _std_reserve);
|
|
}
|
|
reserve();
|
|
}
|
|
|
|
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(blocked_requests_timed_out_error{_name}));
|
|
}
|
|
|
|
future<> prime_segment_pool(size_t available_memory, size_t min_free_memory) {
|
|
return smp::invoke_on_all([=] {
|
|
shard_segment_pool.prime(available_memory, min_free_memory);
|
|
});
|
|
}
|
|
|
|
uint64_t memory_allocated() {
|
|
return shard_segment_pool.statistics().memory_allocated;
|
|
}
|
|
|
|
uint64_t memory_freed() {
|
|
return shard_segment_pool.statistics().memory_freed;
|
|
}
|
|
|
|
uint64_t memory_compacted() {
|
|
return shard_segment_pool.statistics().memory_compacted;
|
|
}
|
|
|
|
uint64_t memory_evicted() {
|
|
return shard_segment_pool.statistics().memory_evicted;
|
|
}
|
|
|
|
occupancy_stats lsa_global_occupancy_stats() {
|
|
return occupancy_stats(shard_segment_pool.total_free_memory(), shard_segment_pool.total_memory_in_use());
|
|
}
|
|
|
|
}
|
|
|
|
// 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();
|
|
}
|