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foundationdb/flow/Arena.cpp

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/*
* Arena.cpp
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2020 Apple Inc. and the FoundationDB project authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "Arena.h"
#include "flow/UnitTest.h"
// See https://dox.ipxe.org/memcheck_8h_source.html and https://dox.ipxe.org/valgrind_8h_source.html for an explanation
// of valgrind client requests
#if VALGRIND
#include <memcheck.h>
#endif
// For each use of arena-internal memory (e.g. ArenaBlock::getSize()), unpoison the memory before use and
// poison it when done.
// When creating a new ArenaBlock, poison the memory that will be later allocated to users.
// When allocating memory to a user, mark that memory as undefined.
namespace {
#if VALGRIND
void allowAccess(ArenaBlock* b) {
if (valgrindPrecise() && b) {
VALGRIND_MAKE_MEM_DEFINED(b, ArenaBlock::TINY_HEADER);
int headerSize = b->isTiny() ? ArenaBlock::TINY_HEADER : sizeof(ArenaBlock);
VALGRIND_MAKE_MEM_DEFINED(b, headerSize);
}
}
void disallowAccess(ArenaBlock* b) {
if (valgrindPrecise() && b) {
int headerSize = b->isTiny() ? ArenaBlock::TINY_HEADER : sizeof(ArenaBlock);
VALGRIND_MAKE_MEM_NOACCESS(b, headerSize);
}
}
void makeNoAccess(void* addr, size_t size) {
if (valgrindPrecise()) {
VALGRIND_MAKE_MEM_NOACCESS(addr, size);
}
}
void makeDefined(void* addr, size_t size) {
if (valgrindPrecise()) {
VALGRIND_MAKE_MEM_DEFINED(addr, size);
}
}
void makeUndefined(void* addr, size_t size) {
if (valgrindPrecise()) {
VALGRIND_MAKE_MEM_UNDEFINED(addr, size);
}
}
#else
void allowAccess(ArenaBlock*) {}
void disallowAccess(ArenaBlock*) {}
void makeNoAccess(void*, size_t) {}
void makeDefined(void*, size_t) {}
void makeUndefined(void*, size_t) {}
#endif
} // namespace
Arena::Arena() : impl(nullptr) {}
Arena::Arena(size_t reservedSize) : impl(0) {
UNSTOPPABLE_ASSERT(reservedSize < std::numeric_limits<int>::max());
if (reservedSize) {
allowAccess(impl.getPtr());
ArenaBlock::create((int)reservedSize, impl);
disallowAccess(impl.getPtr());
}
}
Arena::Arena(const Arena& r) = default;
Arena::Arena(Arena&& r) noexcept = default;
Arena& Arena::operator=(const Arena& r) = default;
Arena& Arena::operator=(Arena&& r) noexcept = default;
void Arena::dependsOn(const Arena& p) {
if (p.impl) {
allowAccess(impl.getPtr());
allowAccess(p.impl.getPtr());
ArenaBlock::dependOn(impl, p.impl.getPtr());
disallowAccess(p.impl.getPtr());
if (p.impl.getPtr() != impl.getPtr()) {
disallowAccess(impl.getPtr());
}
}
}
size_t Arena::getSize() const {
if (impl) {
allowAccess(impl.getPtr());
auto result = impl->totalSize();
disallowAccess(impl.getPtr());
return result;
}
return 0;
}
bool Arena::hasFree(size_t size, const void* address) {
if (impl) {
allowAccess(impl.getPtr());
auto result = impl->unused() >= size && impl->getNextData() == address;
disallowAccess(impl.getPtr());
return result;
}
return false;
}
void ArenaBlock::addref() {
makeDefined(this, sizeof(ThreadSafeReferenceCounted<ArenaBlock>));
ThreadSafeReferenceCounted<ArenaBlock>::addref();
makeNoAccess(this, sizeof(ThreadSafeReferenceCounted<ArenaBlock>));
}
void ArenaBlock::delref() {
makeDefined(this, sizeof(ThreadSafeReferenceCounted<ArenaBlock>));
if (delref_no_destroy()) {
destroy();
} else {
makeNoAccess(this, sizeof(ThreadSafeReferenceCounted<ArenaBlock>));
}
}
bool ArenaBlock::isTiny() const {
return tinySize != NOT_TINY;
}
int ArenaBlock::size() const {
if (isTiny())
return tinySize;
else
return bigSize;
}
int ArenaBlock::used() const {
if (isTiny())
return tinyUsed;
else
return bigUsed;
}
int ArenaBlock::unused() const {
if (isTiny())
return tinySize - tinyUsed;
else
return bigSize - bigUsed;
}
const void* ArenaBlock::getData() const {
return this;
}
const void* ArenaBlock::getNextData() const {
return (const uint8_t*)getData() + used();
}
size_t ArenaBlock::totalSize() {
if (isTiny()) {
return size();
}
size_t s = size();
int o = nextBlockOffset;
while (o) {
ArenaBlockRef* r = (ArenaBlockRef*)((char*)getData() + o);
makeDefined(r, sizeof(ArenaBlockRef));
allowAccess(r->next);
s += r->next->totalSize();
disallowAccess(r->next);
o = r->nextBlockOffset;
makeNoAccess(r, sizeof(ArenaBlockRef));
}
return s;
}
// just for debugging:
void ArenaBlock::getUniqueBlocks(std::set<ArenaBlock*>& a) {
a.insert(this);
if (isTiny()) return;
int o = nextBlockOffset;
while (o) {
ArenaBlockRef* r = (ArenaBlockRef*)((char*)getData() + o);
makeDefined(r, sizeof(ArenaBlockRef));
r->next->getUniqueBlocks(a);
o = r->nextBlockOffset;
makeNoAccess(r, sizeof(ArenaBlockRef));
}
return;
}
int ArenaBlock::addUsed(int bytes) {
if (isTiny()) {
int t = tinyUsed;
tinyUsed += bytes;
return t;
} else {
int t = bigUsed;
bigUsed += bytes;
return t;
}
}
void ArenaBlock::makeReference(ArenaBlock* next) {
ArenaBlockRef* r = (ArenaBlockRef*)((char*)getData() + bigUsed);
makeDefined(r, sizeof(ArenaBlockRef));
r->next = next;
r->nextBlockOffset = nextBlockOffset;
makeNoAccess(r, sizeof(ArenaBlockRef));
nextBlockOffset = bigUsed;
bigUsed += sizeof(ArenaBlockRef);
}
void ArenaBlock::dependOn(Reference<ArenaBlock>& self, ArenaBlock* other) {
other->addref();
if (!self || self->isTiny() || self->unused() < sizeof(ArenaBlockRef))
create(SMALL, self)->makeReference(other);
else
self->makeReference(other);
}
void* ArenaBlock::allocate(Reference<ArenaBlock>& self, int bytes) {
ArenaBlock* b = self.getPtr();
allowAccess(b);
if (!self || self->unused() < bytes) {
auto* tmp = b;
b = create(bytes, self);
disallowAccess(tmp);
}
void* result = (char*)b->getData() + b->addUsed(bytes);
disallowAccess(b);
makeUndefined(result, bytes);
return result;
}
// Return an appropriately-sized ArenaBlock to store the given data
ArenaBlock* ArenaBlock::create(int dataSize, Reference<ArenaBlock>& next) {
ArenaBlock* b;
if (dataSize <= SMALL - TINY_HEADER && !next) {
if (dataSize <= 16 - TINY_HEADER) {
b = (ArenaBlock*)FastAllocator<16>::allocate();
b->tinySize = 16;
INSTRUMENT_ALLOCATE("Arena16");
} else if (dataSize <= 32 - TINY_HEADER) {
b = (ArenaBlock*)FastAllocator<32>::allocate();
b->tinySize = 32;
INSTRUMENT_ALLOCATE("Arena32");
} else {
b = (ArenaBlock*)FastAllocator<64>::allocate();
b->tinySize = 64;
INSTRUMENT_ALLOCATE("Arena64");
}
b->tinyUsed = TINY_HEADER;
} else {
int reqSize = dataSize + sizeof(ArenaBlock);
if (next) reqSize += sizeof(ArenaBlockRef);
if (reqSize < LARGE) {
// Each block should be larger than the previous block, up to a limit, to minimize allocations
// Worst-case allocation pattern: 1 +10 +17 +42 +67 +170 +323 +681 +1348 +2728 +2210 +2211 (+1K +3K+1 +4K)*
// Overhead: 4X for small arenas, 3X intermediate, 1.33X for large arenas
int prevSize = next ? next->size() : 0;
reqSize = std::max(reqSize, std::min(prevSize * 2, std::max(LARGE - 1, reqSize * 4)));
}
if (reqSize < LARGE) {
if (reqSize <= 128) {
b = (ArenaBlock*)FastAllocator<128>::allocate();
b->bigSize = 128;
INSTRUMENT_ALLOCATE("Arena128");
} else if (reqSize <= 256) {
b = (ArenaBlock*)FastAllocator<256>::allocate();
b->bigSize = 256;
INSTRUMENT_ALLOCATE("Arena256");
} else if (reqSize <= 512) {
b = (ArenaBlock*)FastAllocator<512>::allocate();
b->bigSize = 512;
INSTRUMENT_ALLOCATE("Arena512");
} else if (reqSize <= 1024) {
b = (ArenaBlock*)FastAllocator<1024>::allocate();
b->bigSize = 1024;
INSTRUMENT_ALLOCATE("Arena1024");
} else if (reqSize <= 2048) {
b = (ArenaBlock*)FastAllocator<2048>::allocate();
b->bigSize = 2048;
INSTRUMENT_ALLOCATE("Arena2048");
} else if (reqSize <= 4096) {
b = (ArenaBlock*)FastAllocator<4096>::allocate();
b->bigSize = 4096;
INSTRUMENT_ALLOCATE("Arena4096");
} else {
b = (ArenaBlock*)FastAllocator<8192>::allocate();
b->bigSize = 8192;
INSTRUMENT_ALLOCATE("Arena8192");
}
b->tinySize = b->tinyUsed = NOT_TINY;
b->bigUsed = sizeof(ArenaBlock);
} else {
#ifdef ALLOC_INSTRUMENTATION
allocInstr["ArenaHugeKB"].alloc((reqSize + 1023) >> 10);
#endif
b = (ArenaBlock*)new uint8_t[reqSize];
b->tinySize = b->tinyUsed = NOT_TINY;
b->bigSize = reqSize;
b->bigUsed = sizeof(ArenaBlock);
if (FLOW_KNOBS && g_allocation_tracing_disabled == 0 &&
nondeterministicRandom()->random01() < (reqSize / FLOW_KNOBS->HUGE_ARENA_LOGGING_BYTES)) {
++g_allocation_tracing_disabled;
hugeArenaSample(reqSize);
--g_allocation_tracing_disabled;
}
g_hugeArenaMemory.fetch_add(reqSize);
// If the new block has less free space than the old block, make the old block depend on it
if (next && !next->isTiny() && next->unused() >= reqSize - dataSize) {
b->nextBlockOffset = 0;
b->setrefCountUnsafe(1);
next->makeReference(b);
return b;
}
}
b->nextBlockOffset = 0;
if (next) b->makeReference(next.getPtr());
}
b->setrefCountUnsafe(1);
next.setPtrUnsafe(b);
makeNoAccess(reinterpret_cast<uint8_t*>(b) + b->used(), b->unused());
return b;
}
void ArenaBlock::destroy() {
// If the stack never contains more than one item, nothing will be allocated from stackArena.
// If stackArena is used, it will always be a linked list, so destroying *it* will not create another arena
ArenaBlock* tinyStack = this;
allowAccess(this);
Arena stackArena;
VectorRef<ArenaBlock*> stack(&tinyStack, 1);
while (stack.size()) {
ArenaBlock* b = stack.end()[-1];
stack.pop_back();
allowAccess(b);
if (!b->isTiny()) {
int o = b->nextBlockOffset;
while (o) {
ArenaBlockRef* br = (ArenaBlockRef*)((char*)b->getData() + o);
makeDefined(br, sizeof(ArenaBlockRef));
allowAccess(br->next);
if (br->next->delref_no_destroy()) stack.push_back(stackArena, br->next);
disallowAccess(br->next);
o = br->nextBlockOffset;
}
}
b->destroyLeaf();
}
}
void ArenaBlock::destroyLeaf() {
if (isTiny()) {
if (tinySize <= 16) {
FastAllocator<16>::release(this);
INSTRUMENT_RELEASE("Arena16");
} else if (tinySize <= 32) {
FastAllocator<32>::release(this);
INSTRUMENT_RELEASE("Arena32");
} else {
FastAllocator<64>::release(this);
INSTRUMENT_RELEASE("Arena64");
}
} else {
if (bigSize <= 128) {
FastAllocator<128>::release(this);
INSTRUMENT_RELEASE("Arena128");
} else if (bigSize <= 256) {
FastAllocator<256>::release(this);
INSTRUMENT_RELEASE("Arena256");
} else if (bigSize <= 512) {
FastAllocator<512>::release(this);
INSTRUMENT_RELEASE("Arena512");
} else if (bigSize <= 1024) {
FastAllocator<1024>::release(this);
INSTRUMENT_RELEASE("Arena1024");
} else if (bigSize <= 2048) {
FastAllocator<2048>::release(this);
INSTRUMENT_RELEASE("Arena2048");
} else if (bigSize <= 4096) {
FastAllocator<4096>::release(this);
INSTRUMENT_RELEASE("Arena4096");
} else if (bigSize <= 8192) {
FastAllocator<8192>::release(this);
INSTRUMENT_RELEASE("Arena8192");
} else {
#ifdef ALLOC_INSTRUMENTATION
allocInstr["ArenaHugeKB"].dealloc((bigSize + 1023) >> 10);
#endif
g_hugeArenaMemory.fetch_sub(bigSize);
delete[](uint8_t*) this;
}
}
}
namespace {
template <template <class> class VectorRefLike>
void testRangeBasedForLoop() {
VectorRefLike<StringRef> xs;
Arena a;
int size = deterministicRandom()->randomInt(0, 100);
for (int i = 0; i < size; ++i) {
xs.push_back_deep(a, StringRef(std::to_string(i)));
}
ASSERT(xs.size() == size);
int i = 0;
for (const auto& x : xs) {
ASSERT(x == StringRef(std::to_string(i++)));
}
ASSERT(i == size);
}
template <template <class> class VectorRefLike>
void testIteratorIncrement() {
VectorRefLike<StringRef> xs;
Arena a;
int size = deterministicRandom()->randomInt(0, 100);
for (int i = 0; i < size; ++i) {
xs.push_back_deep(a, StringRef(std::to_string(i)));
}
ASSERT(xs.size() == size);
{
int i = 0;
for (auto iter = xs.begin(); iter != xs.end();) {
ASSERT(*iter++ == StringRef(std::to_string(i++)));
}
ASSERT(i == size);
}
{
int i = 0;
for (auto iter = xs.begin(); iter != xs.end() && i < xs.size() - 1;) {
ASSERT(*++iter == StringRef(std::to_string(++i)));
}
}
{
int i = 0;
for (auto iter = xs.begin(); iter < xs.end();) {
ASSERT(*iter == StringRef(std::to_string(i)));
iter += 1;
i += 1;
}
}
if (size > 0) {
int i = xs.size() - 1;
for (auto iter = xs.end() - 1; iter >= xs.begin();) {
ASSERT(*iter == StringRef(std::to_string(i)));
iter -= 1;
i -= 1;
}
}
{
int i = 0;
for (auto iter = xs.begin(); iter < xs.end();) {
ASSERT(*iter == StringRef(std::to_string(i)));
iter = iter + 1;
i += 1;
}
}
if (size > 0) {
int i = xs.size() - 1;
for (auto iter = xs.end() - 1; iter >= xs.begin();) {
ASSERT(*iter == StringRef(std::to_string(i)));
iter = iter - 1;
i -= 1;
}
}
}
template <template <class> class VectorRefLike>
void testReverseIterator() {
VectorRefLike<StringRef> xs;
Arena a;
int size = deterministicRandom()->randomInt(0, 100);
for (int i = 0; i < size; ++i) {
xs.push_back_deep(a, StringRef(std::to_string(i)));
}
ASSERT(xs.size() == size);
int i = xs.size() - 1;
for (auto iter = xs.rbegin(); iter != xs.rend();) {
ASSERT(*iter++ == StringRef(std::to_string(i--)));
}
ASSERT(i == -1);
}
template <template <class> class VectorRefLike>
void testAppend() {
VectorRefLike<StringRef> xs;
Arena a;
int size = deterministicRandom()->randomInt(0, 100);
for (int i = 0; i < size; ++i) {
xs.push_back_deep(a, StringRef(std::to_string(i)));
}
VectorRefLike<StringRef> ys;
ys.append(a, xs.begin(), xs.size());
ASSERT(xs.size() == ys.size());
ASSERT(std::equal(xs.begin(), xs.end(), ys.begin()));
}
template <template <class> class VectorRefLike>
void testCopy() {
Standalone<VectorRefLike<StringRef>> xs;
int size = deterministicRandom()->randomInt(0, 100);
for (int i = 0; i < size; ++i) {
xs.push_back_deep(xs.arena(), StringRef(std::to_string(i)));
}
Arena a;
VectorRefLike<StringRef> ys(a, xs);
xs = Standalone<VectorRefLike<StringRef>>();
int i = 0;
for (const auto& y : ys) {
ASSERT(y == StringRef(std::to_string(i++)));
}
ASSERT(i == size);
}
template <template <class> class VectorRefLike>
void testVectorLike() {
testRangeBasedForLoop<VectorRefLike>();
testIteratorIncrement<VectorRefLike>();
testReverseIterator<VectorRefLike>();
testAppend<VectorRefLike>();
testCopy<VectorRefLike>();
}
} // namespace
// Fix number of template parameters
template <class T>
using VectorRefProxy = VectorRef<T>;
TEST_CASE("/flow/Arena/VectorRef") {
testVectorLike<VectorRefProxy>();
return Void();
}
// Fix number of template parameters
template <class T>
using SmallVectorRefProxy = SmallVectorRef<T>;
TEST_CASE("/flow/Arena/SmallVectorRef") {
testVectorLike<SmallVectorRefProxy>();
return Void();
}
// Fix number of template parameters
template <class T>
using SmallVectorRef10Proxy = SmallVectorRef<T, 10>;
TEST_CASE("/flow/Arena/SmallVectorRef10") {
testVectorLike<SmallVectorRef10Proxy>();
return Void();
}
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