1 /*
2 * Copyright (C) 2022 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "gtest/gtest.h"
18
19 #include <cstddef>
20 #include <thread>
21
22 #include "berberis/base/mmap.h"
23 #include "berberis/base/mmap_pool.h"
24 #include "berberis/base/page_size.h"
25
26 namespace berberis {
27
28 class MmapPoolTest : public ::testing::Test {
29 protected:
30 static constexpr size_t kBlockSize = kMaxPageSize;
31 static constexpr size_t kSizeLimit = 2 * kBlockSize;
32 using Pool = MmapPool<kBlockSize, kSizeLimit>;
33
34 MmapPoolTest() = default;
35
ListLength()36 size_t ListLength() {
37 size_t length = 0;
38 Pool::Node* node = Pool::g_nodes_with_available_blocks_.TopForTesting();
39 while (node) {
40 length++;
41 node = node->next;
42 }
43 return length;
44 }
45
SetUp()46 virtual void SetUp() {
47 // Empty the global pool, possibly populated by other tests.
48 while (ListLength() > 0) {
49 MunmapOrDie(Pool::Alloc(), kBlockSize);
50 }
51 }
52 };
53
54 namespace {
55
TEST_F(MmapPoolTest,Smoke)56 TEST_F(MmapPoolTest, Smoke) {
57 char* p1 = static_cast<char*>(Pool::Alloc());
58 ASSERT_TRUE(p1);
59 p1[kBlockSize - 1] = 'a';
60 EXPECT_EQ(ListLength(), 0u);
61
62 char* p2 = static_cast<char*>(Pool::Alloc());
63 ASSERT_TRUE(p2);
64 p2[kBlockSize - 1] = 'b';
65 EXPECT_EQ(ListLength(), 0u);
66
67 EXPECT_NE(p1, p2);
68
69 char* p3 = static_cast<char*>(Pool::Alloc());
70 ASSERT_TRUE(p3);
71 p3[kBlockSize - 1] = 'c';
72 EXPECT_EQ(ListLength(), 0u);
73
74 Pool::Free(p1);
75 EXPECT_EQ(ListLength(), 1u);
76 p1[kBlockSize - 1] = 'A';
77
78 Pool::Free(p2);
79 EXPECT_EQ(ListLength(), 2u);
80 p2[kBlockSize - 1] = 'B';
81
82 Pool::Free(p3);
83 // Length doesn't change!
84 EXPECT_EQ(ListLength(), 2u);
85 // The block is unmapped.
86 EXPECT_DEATH(p3[kBlockSize - 1] = 'C', "");
87 }
88
TEST_F(MmapPoolTest,Stress)89 TEST_F(MmapPoolTest, Stress) {
90 constexpr size_t kNumThreads = 4;
91 std::thread threads[kNumThreads];
92
93 for (size_t i = 0; i < kNumThreads; i++) {
94 threads[i] = std::thread([]() {
95 for (int c = 0; c < 1024 * 1024; c++) {
96 char* block = static_cast<char*>(Pool::Alloc());
97 block[kBlockSize - 1] = 'a';
98 Pool::Free(block);
99 // ListLength isn't thread-safe, so we cannot use it here. So we just expect that
100 // Alloc/Free cycles do not result in a crash.
101 }
102 });
103 }
104
105 for (auto& thread : threads) {
106 thread.join();
107 }
108 EXPECT_EQ(ListLength(), 2u);
109 }
110
111 } // namespace
112
113 } // namespace berberis
114