Reduce memory lost by ArenaAllocator for large allocations.
When allocating from a new arena, check if the old arena has
more remaining space than the new one after the current
allocation. If so, keep using the old arena to reduce the
amount of "lost" arena memory. This can happen when we try
to allocate more than half the default arena size. If the
allocation exceeds the default arena size, it's very likely
to happen even though the ArenaPool could still provide some
much larger previously allocated arena.
Also avoid artithmetic overflow when checking if the
request can be satisfied from the current arena.
And abort immediately if calloc() fails.
Bug: 28173563
Bug: 28256882
Change-Id: I1b4bda5d3f32ecd95fbd11addd1f0ca6dcc33e45
diff --git a/runtime/base/arena_allocator_test.cc b/runtime/base/arena_allocator_test.cc
new file mode 100644
index 0000000..c07c0ed
--- /dev/null
+++ b/runtime/base/arena_allocator_test.cc
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * 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 "base/arena_allocator.h"
+#include "base/arena_bit_vector.h"
+#include "gtest/gtest.h"
+
+namespace art {
+
+class ArenaAllocatorTest : public testing::Test {
+ protected:
+ size_t NumberOfArenas(ArenaAllocator* arena) {
+ size_t result = 0u;
+ for (Arena* a = arena->arena_head_; a != nullptr; a = a->next_) {
+ ++result;
+ }
+ return result;
+ }
+};
+
+TEST_F(ArenaAllocatorTest, Test) {
+ ArenaPool pool;
+ ArenaAllocator arena(&pool);
+ ArenaBitVector bv(&arena, 10, true);
+ bv.SetBit(5);
+ EXPECT_EQ(1U, bv.GetStorageSize());
+ bv.SetBit(35);
+ EXPECT_EQ(2U, bv.GetStorageSize());
+}
+
+TEST_F(ArenaAllocatorTest, LargeAllocations) {
+ {
+ ArenaPool pool;
+ ArenaAllocator arena(&pool);
+ // Note: Leaving some space for memory tool red zones.
+ void* alloc1 = arena.Alloc(Arena::kDefaultSize * 5 / 8);
+ void* alloc2 = arena.Alloc(Arena::kDefaultSize * 2 / 8);
+ ASSERT_NE(alloc1, alloc2);
+ ASSERT_EQ(1u, NumberOfArenas(&arena));
+ }
+ {
+ ArenaPool pool;
+ ArenaAllocator arena(&pool);
+ void* alloc1 = arena.Alloc(Arena::kDefaultSize * 13 / 16);
+ void* alloc2 = arena.Alloc(Arena::kDefaultSize * 11 / 16);
+ ASSERT_NE(alloc1, alloc2);
+ ASSERT_EQ(2u, NumberOfArenas(&arena));
+ void* alloc3 = arena.Alloc(Arena::kDefaultSize * 7 / 16);
+ ASSERT_NE(alloc1, alloc3);
+ ASSERT_NE(alloc2, alloc3);
+ ASSERT_EQ(3u, NumberOfArenas(&arena));
+ }
+ {
+ ArenaPool pool;
+ ArenaAllocator arena(&pool);
+ void* alloc1 = arena.Alloc(Arena::kDefaultSize * 13 / 16);
+ void* alloc2 = arena.Alloc(Arena::kDefaultSize * 9 / 16);
+ ASSERT_NE(alloc1, alloc2);
+ ASSERT_EQ(2u, NumberOfArenas(&arena));
+ // Note: Leaving some space for memory tool red zones.
+ void* alloc3 = arena.Alloc(Arena::kDefaultSize * 5 / 16);
+ ASSERT_NE(alloc1, alloc3);
+ ASSERT_NE(alloc2, alloc3);
+ ASSERT_EQ(2u, NumberOfArenas(&arena));
+ }
+ {
+ ArenaPool pool;
+ ArenaAllocator arena(&pool);
+ void* alloc1 = arena.Alloc(Arena::kDefaultSize * 9 / 16);
+ void* alloc2 = arena.Alloc(Arena::kDefaultSize * 13 / 16);
+ ASSERT_NE(alloc1, alloc2);
+ ASSERT_EQ(2u, NumberOfArenas(&arena));
+ // Note: Leaving some space for memory tool red zones.
+ void* alloc3 = arena.Alloc(Arena::kDefaultSize * 5 / 16);
+ ASSERT_NE(alloc1, alloc3);
+ ASSERT_NE(alloc2, alloc3);
+ ASSERT_EQ(2u, NumberOfArenas(&arena));
+ }
+ {
+ ArenaPool pool;
+ ArenaAllocator arena(&pool);
+ // Note: Leaving some space for memory tool red zones.
+ for (size_t i = 0; i != 15; ++i) {
+ arena.Alloc(Arena::kDefaultSize * 1 / 16); // Allocate 15 times from the same arena.
+ ASSERT_EQ(i + 1u, NumberOfArenas(&arena));
+ arena.Alloc(Arena::kDefaultSize * 17 / 16); // Allocate a separate arena.
+ ASSERT_EQ(i + 2u, NumberOfArenas(&arena));
+ }
+ }
+}
+
+} // namespace art