1 files changed, 233 insertions, 0 deletions
diff --git a/src/rocksdb/memory/arena.cc b/src/rocksdb/memory/arena.cc
new file mode 100644
index 000000000..ed46459d9
--- /dev/null
+++ b/src/rocksdb/memory/arena.cc
@@ -0,0 +1,233 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include "memory/arena.h"
+#ifndef OS_WIN
+#include <sys/mman.h>
+#endif
+#include <algorithm>
+#include "logging/logging.h"
+#include "port/malloc.h"
+#include "port/port.h"
+#include "rocksdb/env.h"
+#include "test_util/sync_point.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// MSVC complains that it is already defined since it is static in the header.
+#ifndef _MSC_VER
+const size_t Arena::kInlineSize;
+#endif
+
+const size_t Arena::kMinBlockSize = 4096;
+const size_t Arena::kMaxBlockSize = 2u << 30;
+static const int kAlignUnit = alignof(max_align_t);
+
+size_t OptimizeBlockSize(size_t block_size) {
+  // Make sure block_size is in optimal range
+  block_size = std::max(Arena::kMinBlockSize, block_size);
+  block_size = std::min(Arena::kMaxBlockSize, block_size);
+
+  // make sure block_size is the multiple of kAlignUnit
+  if (block_size % kAlignUnit != 0) {
+    block_size = (1 + block_size / kAlignUnit) * kAlignUnit;
+  }
+
+  return block_size;
+}
+
+Arena::Arena(size_t block_size, AllocTracker* tracker, size_t huge_page_size)
+    : kBlockSize(OptimizeBlockSize(block_size)), tracker_(tracker) {
+  assert(kBlockSize >= kMinBlockSize && kBlockSize <= kMaxBlockSize &&
+         kBlockSize % kAlignUnit == 0);
+  TEST_SYNC_POINT_CALLBACK("Arena::Arena:0", const_cast<size_t*>(&kBlockSize));
+  alloc_bytes_remaining_ = sizeof(inline_block_);
+  blocks_memory_ += alloc_bytes_remaining_;
+  aligned_alloc_ptr_ = inline_block_;
+  unaligned_alloc_ptr_ = inline_block_ + alloc_bytes_remaining_;
+#ifdef MAP_HUGETLB
+  hugetlb_size_ = huge_page_size;
+  if (hugetlb_size_ && kBlockSize > hugetlb_size_) {
+    hugetlb_size_ = ((kBlockSize - 1U) / hugetlb_size_ + 1U) * hugetlb_size_;
+  }
+#else
+  (void)huge_page_size;
+#endif
+  if (tracker_ != nullptr) {
+    tracker_->Allocate(kInlineSize);
+  }
+}
+
+Arena::~Arena() {
+  if (tracker_ != nullptr) {
+    assert(tracker_->is_freed());
+    tracker_->FreeMem();
+  }
+  for (const auto& block : blocks_) {
+    delete[] block;
+  }
+
+#ifdef MAP_HUGETLB
+  for (const auto& mmap_info : huge_blocks_) {
+    if (mmap_info.addr_ == nullptr) {
+      continue;
+    }
+    auto ret = munmap(mmap_info.addr_, mmap_info.length_);
+    if (ret != 0) {
+      // TODO(sdong): Better handling
+    }
+  }
+#endif
+}
+
+char* Arena::AllocateFallback(size_t bytes, bool aligned) {
+  if (bytes > kBlockSize / 4) {
+    ++irregular_block_num;
+    // Object is more than a quarter of our block size.  Allocate it separately
+    // to avoid wasting too much space in leftover bytes.
+    return AllocateNewBlock(bytes);
+  }
+
+  // We waste the remaining space in the current block.
+  size_t size = 0;
+  char* block_head = nullptr;
+#ifdef MAP_HUGETLB
+  if (hugetlb_size_) {
+    size = hugetlb_size_;
+    block_head = AllocateFromHugePage(size);
+  }
+#endif
+  if (!block_head) {
+    size = kBlockSize;
+    block_head = AllocateNewBlock(size);
+  }
+  alloc_bytes_remaining_ = size - bytes;
+
+  if (aligned) {
+    aligned_alloc_ptr_ = block_head + bytes;
+    unaligned_alloc_ptr_ = block_head + size;
+    return block_head;
+  } else {
+    aligned_alloc_ptr_ = block_head;
+    unaligned_alloc_ptr_ = block_head + size - bytes;
+    return unaligned_alloc_ptr_;
+  }
+}
+
+char* Arena::AllocateFromHugePage(size_t bytes) {
+#ifdef MAP_HUGETLB
+  if (hugetlb_size_ == 0) {
+    return nullptr;
+  }
+  // Reserve space in `huge_blocks_` before calling `mmap`.
+  // Use `emplace_back()` instead of `reserve()` to let std::vector manage its
+  // own memory and do fewer reallocations.
+  //
+  // - If `emplace_back` throws, no memory leaks because we haven't called
+  //   `mmap` yet.
+  // - If `mmap` throws, no memory leaks because the vector will be cleaned up
+  //   via RAII.
+  huge_blocks_.emplace_back(nullptr /* addr */, 0 /* length */);
+
+  void* addr = mmap(nullptr, bytes, (PROT_READ | PROT_WRITE),
+                    (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB), -1, 0);
+
+  if (addr == MAP_FAILED) {
+    return nullptr;
+  }
+  huge_blocks_.back() = MmapInfo(addr, bytes);
+  blocks_memory_ += bytes;
+  if (tracker_ != nullptr) {
+    tracker_->Allocate(bytes);
+  }
+  return reinterpret_cast<char*>(addr);
+#else
+  (void)bytes;
+  return nullptr;
+#endif
+}
+
+char* Arena::AllocateAligned(size_t bytes, size_t huge_page_size,
+                             Logger* logger) {
+  assert((kAlignUnit & (kAlignUnit - 1)) ==
+         0);  // Pointer size should be a power of 2
+
+#ifdef MAP_HUGETLB
+  if (huge_page_size > 0 && bytes > 0) {
+    // Allocate from a huge page TBL table.
+    assert(logger != nullptr);  // logger need to be passed in.
+    size_t reserved_size =
+        ((bytes - 1U) / huge_page_size + 1U) * huge_page_size;
+    assert(reserved_size >= bytes);
+
+    char* addr = AllocateFromHugePage(reserved_size);
+    if (addr == nullptr) {
+      ROCKS_LOG_WARN(logger,
+                     "AllocateAligned fail to allocate huge TLB pages: %s",
+                     strerror(errno));
+      // fail back to malloc
+    } else {
+      return addr;
+    }
+  }
+#else
+  (void)huge_page_size;
+  (void)logger;
+#endif
+
+  size_t current_mod =
+      reinterpret_cast<uintptr_t>(aligned_alloc_ptr_) & (kAlignUnit - 1);
+  size_t slop = (current_mod == 0 ? 0 : kAlignUnit - current_mod);
+  size_t needed = bytes + slop;
+  char* result;
+  if (needed <= alloc_bytes_remaining_) {
+    result = aligned_alloc_ptr_ + slop;
+    aligned_alloc_ptr_ += needed;
+    alloc_bytes_remaining_ -= needed;
+  } else {
+    // AllocateFallback always returns aligned memory
+    result = AllocateFallback(bytes, true /* aligned */);
+  }
+  assert((reinterpret_cast<uintptr_t>(result) & (kAlignUnit - 1)) == 0);
+  return result;
+}
+
+char* Arena::AllocateNewBlock(size_t block_bytes) {
+  // Reserve space in `blocks_` before allocating memory via new.
+  // Use `emplace_back()` instead of `reserve()` to let std::vector manage its
+  // own memory and do fewer reallocations.
+  //
+  // - If `emplace_back` throws, no memory leaks because we haven't called `new`
+  //   yet.
+  // - If `new` throws, no memory leaks because the vector will be cleaned up
+  //   via RAII.
+  blocks_.emplace_back(nullptr);
+
+  char* block = new char[block_bytes];
+  size_t allocated_size;
+#ifdef ROCKSDB_MALLOC_USABLE_SIZE
+  allocated_size = malloc_usable_size(block);
+#ifndef NDEBUG
+  // It's hard to predict what malloc_usable_size() returns.
+  // A callback can allow users to change the costed size.
+  std::pair<size_t*, size_t*> pair(&allocated_size, &block_bytes);
+  TEST_SYNC_POINT_CALLBACK("Arena::AllocateNewBlock:0", &pair);
+#endif  // NDEBUG
+#else
+  allocated_size = block_bytes;
+#endif  // ROCKSDB_MALLOC_USABLE_SIZE
+  blocks_memory_ += allocated_size;
+  if (tracker_ != nullptr) {
+    tracker_->Allocate(allocated_size);
+  }
+  blocks_.back() = block;
+  return block;
+}
+
+}  // namespace ROCKSDB_NAMESPACE