Add lock-based unbounded queue

...based on the 2-lock algorithm by M. Scott and M. Michael (1992).

BUG=chromium:524425
LOG=N

Review URL: https://codereview.chromium.org/1448283004

Cr-Commit-Position: refs/heads/master@{#32078}

src/locked-queue-inl.h

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_LOCKED_QUEUE_INL_
+#define V8_LOCKED_QUEUE_INL_
+
+#include "src/atomic-utils.h"
+#include "src/locked-queue.h"
+
+namespace v8 {
+namespace internal {
+
+template <typename Record>
+struct LockedQueue<Record>::Node : Malloced {
+  Node() : next(nullptr) {}
+  Record value;
+  AtomicValue<Node*> next;
+};
+
+
+template <typename Record>
+inline LockedQueue<Record>::LockedQueue() {
+  head_ = new Node();
+  CHECK(head_ != nullptr);
+  tail_ = head_;
+}
+
+
+template <typename Record>
+inline LockedQueue<Record>::~LockedQueue() {
+  // Destroy all remaining nodes. Note that we do not destroy the actual values.
+  Node* old_node = nullptr;
+  Node* cur_node = head_;
+  while (cur_node != nullptr) {
+    old_node = cur_node;
+    cur_node = cur_node->next.Value();
+    delete old_node;
+  }
+}
+
+
+template <typename Record>
+inline void LockedQueue<Record>::Enqueue(const Record& record) {
+  Node* n = new Node();
+  CHECK(n != nullptr);
+  n->value = record;
+  {
+    base::LockGuard<base::Mutex> guard(&tail_mutex_);
+    tail_->next.SetValue(n);
+    tail_ = n;
+  }
+}
+
+
+template <typename Record>
+inline bool LockedQueue<Record>::Dequeue(Record* record) {
+  Node* old_head = nullptr;
+  {
+    base::LockGuard<base::Mutex> guard(&head_mutex_);
+    old_head = head_;
+    Node* const next_node = head_->next.Value();
+    if (next_node == nullptr) return false;
+    *record = next_node->value;
+    head_ = next_node;
+  }
+  delete old_head;
+  return true;
+}
+
+
+template <typename Record>
+inline bool LockedQueue<Record>::IsEmpty() const {
+  base::LockGuard<base::Mutex> guard(&head_mutex_);
+  return head_->next.Value() == nullptr;
+}
+
+
+template <typename Record>
+inline bool LockedQueue<Record>::Peek(Record* record) const {
+  base::LockGuard<base::Mutex> guard(&head_mutex_);
+  Node* const next_node = head_->next.Value();
+  if (next_node == nullptr) return false;
+  *record = next_node->value;
+  return true;
+}
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_LOCKED_QUEUE_INL_

src/locked-queue.h

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_LOCKED_QUEUE_
+#define V8_LOCKED_QUEUE_
+
+#include "src/allocation.h"
+#include "src/base/platform/platform.h"
+
+namespace v8 {
+namespace internal {
+
+// Simple lock-based unbounded size queue (multi producer; multi consumer) based
+// on "Simple, Fast, and Practical Non-Blocking and Blocking Concurrent Queue
+// Algorithms" by M. Scott and M. Michael.
+// See:
+// https://www.cs.rochester.edu/research/synchronization/pseudocode/queues.html
+template <typename Record>
+class LockedQueue final BASE_EMBEDDED {
+ public:
+  inline LockedQueue();
+  inline ~LockedQueue();
+  inline void Enqueue(const Record& record);
+  inline bool Dequeue(Record* record);
+  inline bool IsEmpty() const;
+  inline bool Peek(Record* record) const;
+
+ private:
+  struct Node;
+
+  mutable base::Mutex head_mutex_;
+  base::Mutex tail_mutex_;
+  Node* head_;
+  Node* tail_;
+
+  DISALLOW_COPY_AND_ASSIGN(LockedQueue);
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_LOCKED_QUEUE_

test/unittests/locked-queue-unittest.cc

+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/locked-queue-inl.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace {
+
+typedef int Record;
+
+}  // namespace
+
+namespace v8 {
+namespace internal {
+
+TEST(LockedQueue, ConstructorEmpty) {
+  LockedQueue<Record> queue;
+  EXPECT_TRUE(queue.IsEmpty());
+}
+
+
+TEST(LockedQueue, SingleRecordEnqueueDequeue) {
+  LockedQueue<Record> queue;
+  EXPECT_TRUE(queue.IsEmpty());
+  queue.Enqueue(1);
+  EXPECT_FALSE(queue.IsEmpty());
+  Record a = -1;
+  bool success = queue.Dequeue(&a);
+  EXPECT_TRUE(success);
+  EXPECT_EQ(a, 1);
+  EXPECT_TRUE(queue.IsEmpty());
+}
+
+
+TEST(LockedQueue, Peek) {
+  LockedQueue<Record> queue;
+  EXPECT_TRUE(queue.IsEmpty());
+  queue.Enqueue(1);
+  EXPECT_FALSE(queue.IsEmpty());
+  Record a = -1;
+  bool success = queue.Peek(&a);
+  EXPECT_TRUE(success);
+  EXPECT_EQ(a, 1);
+  EXPECT_FALSE(queue.IsEmpty());
+  success = queue.Dequeue(&a);
+  EXPECT_TRUE(success);
+  EXPECT_EQ(a, 1);
+  EXPECT_TRUE(queue.IsEmpty());
+}
+
+
+TEST(LockedQueue, PeekOnEmpty) {
+  LockedQueue<Record> queue;
+  EXPECT_TRUE(queue.IsEmpty());
+  Record a = -1;
+  bool success = queue.Peek(&a);
+  EXPECT_FALSE(success);
+}
+
+
+TEST(LockedQueue, MultipleRecords) {
+  LockedQueue<Record> queue;
+  EXPECT_TRUE(queue.IsEmpty());
+  queue.Enqueue(1);
+  EXPECT_FALSE(queue.IsEmpty());
+  for (int i = 2; i <= 5; ++i) {
+    queue.Enqueue(i);
+    EXPECT_FALSE(queue.IsEmpty());
+  }
+  Record rec = 0;
+  for (int i = 1; i <= 4; ++i) {
+    EXPECT_FALSE(queue.IsEmpty());
+    queue.Dequeue(&rec);
+    EXPECT_EQ(i, rec);
+  }
+  for (int i = 6; i <= 12; ++i) {
+    queue.Enqueue(i);
+    EXPECT_FALSE(queue.IsEmpty());
+  }
+  for (int i = 5; i <= 12; ++i) {
+    EXPECT_FALSE(queue.IsEmpty());
+    queue.Dequeue(&rec);
+    EXPECT_EQ(i, rec);
+  }
+  EXPECT_TRUE(queue.IsEmpty());
+}
+
+}  // namespace internal
+}  // namespace v8

test/unittests/unittests.gyp

@@ -110,6 +110,7 @@
         'heap/memory-reducer-unittest.cc',
         'heap/heap-unittest.cc',
         'heap/scavenge-job-unittest.cc',
+        'locked-queue-unittest.cc',
         'run-all-unittests.cc',
         'runtime/runtime-interpreter-unittest.cc',
         'test-utils.h',

tools/gyp/v8.gyp

@@ -854,6 +854,8 @@
         '../../src/layout-descriptor.h',
         '../../src/list-inl.h',
         '../../src/list.h',
+        '../../src/locked-queue-inl.h',
+        '../../src/locked-queue.h',
         '../../src/log-inl.h',
         '../../src/log-utils.cc',
         '../../src/log-utils.h',