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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "bufferstate.h"
#include <vespa/vespalib/util/memory_allocator.h>
#include <limits>
#include <cassert>
using vespalib::alloc::Alloc;
using vespalib::alloc::MemoryAllocator;
namespace vespalib::datastore {
BufferState::BufferState()
: _stats(),
_free_list(_stats.dead_entries_ref()),
_typeHandler(nullptr),
_buffer(Alloc::alloc(0, MemoryAllocator::HUGEPAGE_SIZE)),
_arraySize(0),
_typeId(0),
_state(State::FREE),
_disable_entry_hold_list(false),
_compacting(false)
{
}
BufferState::~BufferState()
{
assert(getState() == State::FREE);
assert(!_free_list.enabled());
assert(_free_list.empty());
assert(_stats.hold_entries() == 0);
}
namespace {
struct AllocResult {
size_t entries;
size_t bytes;
AllocResult(size_t entries_, size_t bytes_) : entries(entries_), bytes(bytes_) {}
};
size_t
roundUpToMatchAllocator(size_t sz)
{
if (sz == 0) {
return 0;
}
// We round up the wanted number of bytes to allocate to match
// the underlying allocator to ensure little to no waste of allocated memory.
if (sz < MemoryAllocator::HUGEPAGE_SIZE) {
// Match heap allocator in vespamalloc.
return vespalib::roundUp2inN(sz);
} else {
// Match mmap allocator.
return MemoryAllocator::roundUpToHugePages(sz);
}
}
AllocResult
calc_allocation(uint32_t bufferId,
BufferTypeBase &typeHandler,
size_t free_entries_needed,
bool resizing)
{
size_t alloc_entries = typeHandler.calc_entries_to_alloc(bufferId, free_entries_needed, resizing);
size_t entry_size = typeHandler.entry_size();
auto buffer_underflow_size = typeHandler.buffer_underflow_size();
size_t allocBytes = roundUpToMatchAllocator(alloc_entries * entry_size + buffer_underflow_size);
size_t maxAllocBytes = typeHandler.get_max_entries() * entry_size + buffer_underflow_size;
if (allocBytes > maxAllocBytes) {
// Ensure that allocated bytes does not exceed the maximum handled by this type.
allocBytes = maxAllocBytes;
}
size_t adjusted_alloc_entries = (allocBytes - buffer_underflow_size) / entry_size;
return AllocResult(adjusted_alloc_entries, allocBytes);
}
}
void
BufferState::on_active(uint32_t bufferId, uint32_t typeId,
BufferTypeBase *typeHandler,
size_t free_entries_needed,
std::atomic<void*>& buffer)
{
assert(buffer.load(std::memory_order_relaxed) == nullptr);
assert(_buffer.get() == nullptr);
assert(getState() == State::FREE);
assert(_typeHandler == nullptr);
assert(capacity() == 0);
assert(size() == 0);
assert(_stats.dead_entries() == 0u);
assert(_stats.hold_entries() == 0);
assert(_stats.extra_used_bytes() == 0);
assert(_stats.extra_hold_bytes() == 0);
assert(_free_list.empty());
size_t reserved_entries = typeHandler->get_reserved_entries(bufferId);
(void) reserved_entries;
AllocResult alloc = calc_allocation(bufferId, *typeHandler, free_entries_needed, false);
assert(alloc.entries >= reserved_entries + free_entries_needed);
auto allocator = typeHandler->get_memory_allocator();
_buffer = (allocator != nullptr) ? Alloc::alloc_with_allocator(allocator) : Alloc::alloc(0, MemoryAllocator::HUGEPAGE_SIZE);
_buffer.create(alloc.bytes).swap(_buffer);
assert(_buffer.get() != nullptr || alloc.entries == 0u);
auto buffer_underflow_size = typeHandler->buffer_underflow_size();
buffer.store(get_buffer(buffer_underflow_size), std::memory_order_release);
_stats.set_alloc_entries(alloc.entries);
_typeHandler.store(typeHandler, std::memory_order_release);
assert(typeId <= std::numeric_limits<uint16_t>::max());
_typeId = typeId;
_arraySize = typeHandler->getArraySize();
_state.store(State::ACTIVE, std::memory_order_release);
typeHandler->on_active(bufferId, &_stats.used_entries_ref(), &_stats.dead_entries_ref(),
buffer.load(std::memory_order::relaxed));
}
void
BufferState::onHold(uint32_t buffer_id)
{
assert(getState() == State::ACTIVE);
auto type_handler = getTypeHandler();
assert(type_handler != nullptr);
_state.store(State::HOLD, std::memory_order_release);
_compacting = false;
assert(_stats.dead_entries() <= size());
assert(_stats.hold_entries() <= (size() - _stats.dead_entries()));
_stats.set_dead_entries(0);
_stats.set_hold_entries(size());
type_handler->on_hold(buffer_id, &_stats.used_entries_ref(), &_stats.dead_entries_ref());
_free_list.disable();
}
void
BufferState::onFree(std::atomic<void*>& buffer)
{
assert(getState() == State::HOLD);
auto type_handler = getTypeHandler();
assert(type_handler != nullptr);
assert(buffer.load(std::memory_order_relaxed) == get_buffer(type_handler->buffer_underflow_size()));
assert(_stats.dead_entries() <= size());
assert(_stats.hold_entries() == (size() - _stats.dead_entries()));
type_handler->destroy_entries(buffer, size());
Alloc::alloc().swap(_buffer);
type_handler->on_free(size());
buffer.store(nullptr, std::memory_order_release);
_stats.clear();
_state.store(State::FREE, std::memory_order_release);
_typeHandler = nullptr;
_arraySize = 0;
assert(!_free_list.enabled());
assert(_free_list.empty());
_disable_entry_hold_list = false;
}
void
BufferState::dropBuffer(uint32_t buffer_id, std::atomic<void*>& buffer)
{
if (getState() == State::FREE) {
assert(buffer.load(std::memory_order_relaxed) == nullptr);
return;
}
assert(buffer.load(std::memory_order_relaxed) != nullptr || capacity() == 0);
if (getState() == State::ACTIVE) {
onHold(buffer_id);
}
if (getState() == State::HOLD) {
onFree(buffer);
}
assert(getState() == State::FREE);
assert(buffer.load(std::memory_order_relaxed) == nullptr);
}
void
BufferState::disable_entry_hold_list()
{
_disable_entry_hold_list = true;
}
bool
BufferState::hold_entries(size_t num_entries, size_t extra_bytes)
{
assert(isActive());
if (_disable_entry_hold_list) {
// The elements are directly marked as dead as they are not put on hold.
_stats.inc_dead_entries(num_entries);
return true;
}
_stats.inc_hold_entries(num_entries);
_stats.inc_extra_hold_bytes(extra_bytes);
return false;
}
void
BufferState::free_entries(EntryRef ref, size_t num_entries, size_t ref_offset)
{
if (isActive()) {
if (_free_list.enabled() && (num_entries == 1)) {
_free_list.push_entry(ref);
}
} else {
assert(isOnHold());
}
_stats.inc_dead_entries(num_entries);
_stats.dec_hold_entries(num_entries);
auto type_handler = getTypeHandler();
auto buffer_underflow_size = type_handler->buffer_underflow_size();
type_handler->clean_hold(get_buffer(buffer_underflow_size), ref_offset, num_entries,
BufferTypeBase::CleanContext(_stats.extra_used_bytes_ref(),
_stats.extra_hold_bytes_ref()));
}
void
BufferState::fallback_resize(uint32_t bufferId,
size_t free_entries_needed,
std::atomic<void*>& buffer,
Alloc &holdBuffer)
{
assert(getState() == State::ACTIVE);
auto type_handler = getTypeHandler();
assert(type_handler != nullptr);
assert(holdBuffer.get() == nullptr);
auto buffer_underflow_size = type_handler->buffer_underflow_size();
AllocResult alloc = calc_allocation(bufferId, *type_handler, free_entries_needed, true);
assert(alloc.entries >= size() + free_entries_needed);
assert(alloc.entries > capacity());
Alloc newBuffer = _buffer.create(alloc.bytes);
type_handler->fallback_copy(get_buffer(newBuffer, buffer_underflow_size), buffer.load(std::memory_order_relaxed), size());
holdBuffer.swap(_buffer);
std::atomic_thread_fence(std::memory_order_release);
_buffer = std::move(newBuffer);
buffer.store(get_buffer(buffer_underflow_size), std::memory_order_release);
_stats.set_alloc_entries(alloc.entries);
}
void
BufferState::resume_primary_buffer(uint32_t buffer_id)
{
getTypeHandler()->resume_primary_buffer(buffer_id, &_stats.used_entries_ref(), &_stats.dead_entries_ref());
}
}
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