Revert of Use DiscardableMemoryManager on Android.

base/memory/discardable_memory_allocator_android_unittest.cc

Index: base/memory/discardable_memory_allocator_android_unittest.cc
diff --git a/base/memory/discardable_memory_allocator_android_unittest.cc b/base/memory/discardable_memory_allocator_android_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b2e8d558608fb03c6f5a5142e63f1d30ef30009b
--- /dev/null
+++ b/base/memory/discardable_memory_allocator_android_unittest.cc
@@ -0,0 +1,303 @@
+// Copyright 2013 The Chromium 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 "base/memory/discardable_memory_allocator_android.h"
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "base/memory/discardable_memory.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
+#include "base/strings/stringprintf.h"
+#include "build/build_config.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace internal {
+
+const char kAllocatorName[] = "allocator-for-testing";
+
+const size_t kAshmemRegionSizeForTesting = 32 * 1024 * 1024;
+const size_t kPageSize = 4096;
+
+const size_t kMaxAllowedAllocationSize =
+    std::numeric_limits<size_t>::max() - kPageSize + 1;
+
+class DiscardableMemoryAllocatorTest : public testing::Test {
+ protected:
+  DiscardableMemoryAllocatorTest()
+      : allocator_(kAllocatorName, kAshmemRegionSizeForTesting) {
+  }
+
+  DiscardableMemoryAllocator allocator_;
+};
+
+void WriteToDiscardableMemory(DiscardableMemory* memory, size_t size) {
+  // Write to the first and the last pages only to avoid paging in up to 64
+  // MBytes.
+  static_cast<char*>(memory->Memory())[0] = 'a';
+  static_cast<char*>(memory->Memory())[size - 1] = 'a';
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, Basic) {
+  const size_t size = 128;
+  scoped_ptr<DiscardableMemory> memory(allocator_.Allocate(size));
+  ASSERT_TRUE(memory);
+  WriteToDiscardableMemory(memory.get(), size);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, ZeroAllocationIsNotSupported) {
+  scoped_ptr<DiscardableMemory> memory(allocator_.Allocate(0));
+  ASSERT_FALSE(memory);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, TooLargeAllocationFails) {
+  scoped_ptr<DiscardableMemory> memory(
+      allocator_.Allocate(kMaxAllowedAllocationSize + 1));
+  // Page-alignment would have caused an overflow resulting in a small
+  // allocation if the input size wasn't checked correctly.
+  ASSERT_FALSE(memory);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest,
+       AshmemRegionsAreNotSmallerThanRequestedSize) {
+  // The creation of the underlying ashmem region is expected to fail since
+  // there should not be enough room in the address space. When ashmem creation
+  // fails, the allocator repetitively retries by dividing the size by 2. This
+  // size should not be smaller than the size the user requested so the
+  // allocation here should just fail (and not succeed with the minimum ashmem
+  // region size).
+  scoped_ptr<DiscardableMemory> memory(
+      allocator_.Allocate(kMaxAllowedAllocationSize));
+  ASSERT_FALSE(memory);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, AshmemRegionsAreAlwaysPageAligned) {
+  // Use a separate allocator here so that we can override the ashmem region
+  // size.
+  DiscardableMemoryAllocator allocator(
+      kAllocatorName, kMaxAllowedAllocationSize);
+  scoped_ptr<DiscardableMemory> memory(allocator.Allocate(kPageSize));
+  ASSERT_TRUE(memory);
+  EXPECT_GT(kMaxAllowedAllocationSize, allocator.last_ashmem_region_size());
+  ASSERT_TRUE(allocator.last_ashmem_region_size() % kPageSize == 0);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, LargeAllocation) {
+  // Note that large allocations should just use DiscardableMemoryAndroidSimple
+  // instead.
+  const size_t size = 64 * 1024 * 1024;
+  scoped_ptr<DiscardableMemory> memory(allocator_.Allocate(size));
+  ASSERT_TRUE(memory);
+  WriteToDiscardableMemory(memory.get(), size);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, ChunksArePageAligned) {
+  scoped_ptr<DiscardableMemory> memory(allocator_.Allocate(kPageSize));
+  ASSERT_TRUE(memory);
+  EXPECT_EQ(0U, reinterpret_cast<uint64_t>(memory->Memory()) % kPageSize);
+  WriteToDiscardableMemory(memory.get(), kPageSize);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, AllocateFreeAllocate) {
+  scoped_ptr<DiscardableMemory> memory(allocator_.Allocate(kPageSize));
+  // Extra allocation that prevents the region from being deleted when |memory|
+  // gets deleted.
+  scoped_ptr<DiscardableMemory> memory_lock(allocator_.Allocate(kPageSize));
+  ASSERT_TRUE(memory);
+  void* const address = memory->Memory();
+  memory->Unlock();  // Tests that the reused chunk is being locked correctly.
+  memory.reset();
+  memory = allocator_.Allocate(kPageSize);
+  ASSERT_TRUE(memory);
+  // The previously freed chunk should be reused.
+  EXPECT_EQ(address, memory->Memory());
+  WriteToDiscardableMemory(memory.get(), kPageSize);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, FreeingWholeAshmemRegionClosesAshmem) {
+  scoped_ptr<DiscardableMemory> memory(allocator_.Allocate(kPageSize));
+  ASSERT_TRUE(memory);
+  const int kMagic = 0xdeadbeef;
+  *static_cast<int*>(memory->Memory()) = kMagic;
+  memory.reset();
+  // The previous ashmem region should have been closed thus it should not be
+  // reused.
+  memory = allocator_.Allocate(kPageSize);
+  ASSERT_TRUE(memory);
+  EXPECT_NE(kMagic, *static_cast<const int*>(memory->Memory()));
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, AllocateUsesBestFitAlgorithm) {
+  scoped_ptr<DiscardableMemory> memory1(allocator_.Allocate(3 * kPageSize));
+  ASSERT_TRUE(memory1);
+  scoped_ptr<DiscardableMemory> memory2(allocator_.Allocate(2 * kPageSize));
+  ASSERT_TRUE(memory2);
+  scoped_ptr<DiscardableMemory> memory3(allocator_.Allocate(1 * kPageSize));
+  ASSERT_TRUE(memory3);
+  void* const address_3 = memory3->Memory();
+  memory1.reset();
+  // Don't free |memory2| to avoid merging the 3 blocks together.
+  memory3.reset();
+  memory1 = allocator_.Allocate(1 * kPageSize);
+  ASSERT_TRUE(memory1);
+  // The chunk whose size is closest to the requested size should be reused.
+  EXPECT_EQ(address_3, memory1->Memory());
+  WriteToDiscardableMemory(memory1.get(), kPageSize);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, MergeFreeChunks) {
+  scoped_ptr<DiscardableMemory> memory1(allocator_.Allocate(kPageSize));
+  ASSERT_TRUE(memory1);
+  scoped_ptr<DiscardableMemory> memory2(allocator_.Allocate(kPageSize));
+  ASSERT_TRUE(memory2);
+  scoped_ptr<DiscardableMemory> memory3(allocator_.Allocate(kPageSize));
+  ASSERT_TRUE(memory3);
+  scoped_ptr<DiscardableMemory> memory4(allocator_.Allocate(kPageSize));
+  ASSERT_TRUE(memory4);
+  void* const memory1_address = memory1->Memory();
+  memory1.reset();
+  memory3.reset();
+  // Freeing |memory2| (located between memory1 and memory3) should merge the
+  // three free blocks together.
+  memory2.reset();
+  memory1 = allocator_.Allocate(3 * kPageSize);
+  EXPECT_EQ(memory1_address, memory1->Memory());
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, MergeFreeChunksAdvanced) {
+  scoped_ptr<DiscardableMemory> memory1(allocator_.Allocate(4 * kPageSize));
+  ASSERT_TRUE(memory1);
+  scoped_ptr<DiscardableMemory> memory2(allocator_.Allocate(4 * kPageSize));
+  ASSERT_TRUE(memory2);
+  void* const memory1_address = memory1->Memory();
+  memory1.reset();
+  memory1 = allocator_.Allocate(2 * kPageSize);
+  memory2.reset();
+  // At this point, the region should be in this state:
+  // 8 KBytes (used), 24 KBytes (free).
+  memory2 = allocator_.Allocate(6 * kPageSize);
+  EXPECT_EQ(
+      static_cast<const char*>(memory2->Memory()),
+      static_cast<const char*>(memory1_address) + 2 * kPageSize);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, MergeFreeChunksAdvanced2) {
+  scoped_ptr<DiscardableMemory> memory1(allocator_.Allocate(4 * kPageSize));
+  ASSERT_TRUE(memory1);
+  scoped_ptr<DiscardableMemory> memory2(allocator_.Allocate(4 * kPageSize));
+  ASSERT_TRUE(memory2);
+  void* const memory1_address = memory1->Memory();
+  memory1.reset();
+  memory1 = allocator_.Allocate(2 * kPageSize);
+  scoped_ptr<DiscardableMemory> memory3(allocator_.Allocate(2 * kPageSize));
+  // At this point, the region should be in this state:
+  // 8 KBytes (used), 8 KBytes (used), 16 KBytes (used).
+  memory3.reset();
+  memory2.reset();
+  // At this point, the region should be in this state:
+  // 8 KBytes (used), 24 KBytes (free).
+  memory2 = allocator_.Allocate(6 * kPageSize);
+  EXPECT_EQ(
+      static_cast<const char*>(memory2->Memory()),
+      static_cast<const char*>(memory1_address) + 2 * kPageSize);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, MergeFreeChunksAndDeleteAshmemRegion) {
+  scoped_ptr<DiscardableMemory> memory1(allocator_.Allocate(4 * kPageSize));
+  ASSERT_TRUE(memory1);
+  scoped_ptr<DiscardableMemory> memory2(allocator_.Allocate(4 * kPageSize));
+  ASSERT_TRUE(memory2);
+  memory1.reset();
+  memory1 = allocator_.Allocate(2 * kPageSize);
+  scoped_ptr<DiscardableMemory> memory3(allocator_.Allocate(2 * kPageSize));
+  // At this point, the region should be in this state:
+  // 8 KBytes (used), 8 KBytes (used), 16 KBytes (used).
+  memory1.reset();
+  memory3.reset();
+  // At this point, the region should be in this state:
+  // 8 KBytes (free), 8 KBytes (used), 8 KBytes (free).
+  const int kMagic = 0xdeadbeef;
+  *static_cast<int*>(memory2->Memory()) = kMagic;
+  memory2.reset();
+  // The whole region should have been deleted.
+  memory2 = allocator_.Allocate(2 * kPageSize);
+  EXPECT_NE(kMagic, *static_cast<int*>(memory2->Memory()));
+}
+
+TEST_F(DiscardableMemoryAllocatorTest,
+     TooLargeFreeChunksDontCauseTooMuchFragmentationWhenRecycled) {
+  // Keep |memory_1| below allocated so that the ashmem region doesn't get
+  // closed when |memory_2| is deleted.
+  scoped_ptr<DiscardableMemory> memory_1(allocator_.Allocate(64 * 1024));
+  ASSERT_TRUE(memory_1);
+  scoped_ptr<DiscardableMemory> memory_2(allocator_.Allocate(32 * 1024));
+  ASSERT_TRUE(memory_2);
+  void* const address = memory_2->Memory();
+  memory_2.reset();
+  const size_t size = 16 * 1024;
+  memory_2 = allocator_.Allocate(size);
+  ASSERT_TRUE(memory_2);
+  EXPECT_EQ(address, memory_2->Memory());
+  WriteToDiscardableMemory(memory_2.get(), size);
+  scoped_ptr<DiscardableMemory> memory_3(allocator_.Allocate(size));
+  // The unused tail (16 KBytes large) of the previously freed chunk should be
+  // reused.
+  EXPECT_EQ(static_cast<char*>(address) + size, memory_3->Memory());
+  WriteToDiscardableMemory(memory_3.get(), size);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest, UseMultipleAshmemRegions) {
+  // Leave one page untouched at the end of the ashmem region.
+  const size_t size = kAshmemRegionSizeForTesting - kPageSize;
+  scoped_ptr<DiscardableMemory> memory1(allocator_.Allocate(size));
+  ASSERT_TRUE(memory1);
+  WriteToDiscardableMemory(memory1.get(), size);
+
+  scoped_ptr<DiscardableMemory> memory2(
+      allocator_.Allocate(kAshmemRegionSizeForTesting));
+  ASSERT_TRUE(memory2);
+  WriteToDiscardableMemory(memory2.get(), kAshmemRegionSizeForTesting);
+  // The last page of the first ashmem region should be used for this
+  // allocation.
+  scoped_ptr<DiscardableMemory> memory3(allocator_.Allocate(kPageSize));
+  ASSERT_TRUE(memory3);
+  WriteToDiscardableMemory(memory3.get(), kPageSize);
+  EXPECT_EQ(memory3->Memory(), static_cast<char*>(memory1->Memory()) + size);
+}
+
+TEST_F(DiscardableMemoryAllocatorTest,
+       HighestAllocatedChunkPointerIsUpdatedWhenHighestChunkGetsSplit) {
+  // Prevents the ashmem region from getting closed when |memory2| gets freed.
+  scoped_ptr<DiscardableMemory> memory1(allocator_.Allocate(kPageSize));
+  ASSERT_TRUE(memory1);
+
+  scoped_ptr<DiscardableMemory> memory2(allocator_.Allocate(4 * kPageSize));
+  ASSERT_TRUE(memory2);
+
+  memory2.reset();
+  memory2 = allocator_.Allocate(kPageSize);
+  // There should now be a free chunk of size 3 * |kPageSize| starting at offset
+  // 2 * |kPageSize| and the pointer to the highest allocated chunk should have
+  // also been updated to |base_| + 2 * |kPageSize|. This pointer is used to
+  // maintain the container mapping a chunk address to its previous chunk and
+  // this map is in turn used while merging previous contiguous chunks.
+
+  // Allocate more than 3 * |kPageSize| so that the free chunk of size 3 *
+  // |kPageSize| is not reused and |highest_allocated_chunk_| gets used instead.
+  scoped_ptr<DiscardableMemory> memory3(allocator_.Allocate(4 * kPageSize));
+  ASSERT_TRUE(memory3);
+
+  // Deleting |memory3| (whose size is 4 * |kPageSize|) should result in a merge
+  // with its previous chunk which is the free chunk of size |3 * kPageSize|.
+  memory3.reset();
+  memory3 = allocator_.Allocate((3 + 4) * kPageSize);
+  EXPECT_EQ(memory3->Memory(),
+            static_cast<const char*>(memory2->Memory()) + kPageSize);
+}
+
+}  // namespace internal
+}  // namespace base