Substitute pow2bin allocator with a dlmalloc based allocator (#71)

* Add dlmalloc_strat allocator strategy
 - Use mspace variant to ease encapsulation
 - Make pow2bins and dlmalloc cmake selectable
* Add unit tester for dlmalloc, rework single_heap, pow2bins unit testers
accordingly
 - add dlmalloc get_used/get_avail, and have all strats allocators also have a get_used
 - Rework memallocator unit tests: bin size is per strat, alignment is verified in singleheap
* bugfix: dlmalloc exposed that the pingpong test would write past end of
allocation with -w 32
* iostream leakage/mixed usage of cerr and fprintf(stderr

---------

Signed-off-by: Aurelien Bouteiller <aurelien.bouteiller@amd.com>

tests/unit_tests/CMakeLists.txt

@@ -84,6 +84,7 @@ target_sources(
     single_heap_gtest.cpp
     symmetric_heap_gtest.cpp
     pow2_bins_gtest.cpp
+    dlmalloc_gtest.cpp
     remote_heap_info_gtest.cpp
     mpi_init_singleton_gtest.cpp
     abql_block_mutex_gtest.cpp

tests/unit_tests/dlmalloc_gtest.cpp

@@ -0,0 +1,130 @@
+/******************************************************************************
+ * Copyright (c) Advanced Micro Devices, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *****************************************************************************/
+
+#include "dlmalloc_gtest.hpp"
+#include <cstdint>
+
+using namespace rocshmem;
+
+// a small portion of the heap is not available due to cost of dlmalloc bookkeeping
+#define DLMALLOC_BOOKKEEPING static_cast<size_t>(128 * ALIGNMENT)
+
+TEST_F(DLMallocTestFixture, used_0_bytes) {
+  size_t heap_size{1 << 30};
+  ASSERT_LE(strat_.get_used(), DLMALLOC_BOOKKEEPING);
+  ASSERT_EQ(strat_.get_used() + strat_.get_avail(), heap_size);
+}
+
+TEST_F(DLMallocTestFixture, alloc_0_bytes) {
+  size_t initial_used{strat_.get_used()};
+  char* c_ptr{nullptr};
+  size_t size{0};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_EQ(c_ptr, nullptr);
+  ASSERT_EQ(strat_.get_used(), initial_used);
+}
+
+TEST_F(DLMallocTestFixture, alloc_1_byte) {
+  char* c_ptr{nullptr};
+  size_t size{1};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+}
+
+TEST_F(DLMallocTestFixture, alloc_128_bytes) {
+  char* c_ptr{nullptr};
+  size_t size{128};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+}
+
+TEST_F(DLMallocTestFixture, alloc_256_bytes) {
+  char* c_ptr{nullptr};
+  size_t size{256};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+}
+
+TEST_F(DLMallocTestFixture, alloc_512_bytes) {
+  char* c_ptr{nullptr};
+  size_t size{512};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+}
+
+TEST_F(DLMallocTestFixture, alloc_513_bytes) {
+  char* c_ptr{nullptr};
+  size_t size{513};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+}
+
+TEST_F(DLMallocTestFixture, alloc_4KB) {
+  char* c_ptr{nullptr};
+  size_t size{4096};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+}
+
+TEST_F(DLMallocTestFixture, alloc_128KB) {
+  char* c_ptr{nullptr};
+  size_t size{131072};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+}
+
+TEST_F(DLMallocTestFixture, alloc_1GB) {
+  char* c_ptr{nullptr};
+  size_t heap_size{1 << 30};
+  size_t size{heap_size - DLMALLOC_BOOKKEEPING};
+
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+  ASSERT_EQ(strat_.get_used() + strat_.get_avail(), heap_size);
+}
+
+TEST_F(DLMallocTestFixture, alloc_256_bytes_X2_free_256_bytes_X2) {
+  char* c_ptr_1{nullptr};
+  char* c_ptr_2{nullptr};
+  size_t size{256};
+  strat_.alloc(&c_ptr_1, size);
+  ASSERT_NE(c_ptr_1, nullptr);
+  strat_.alloc(&c_ptr_2, size);
+  ASSERT_NE(c_ptr_2, nullptr);
+
+  strat_.free(c_ptr_1);
+  strat_.free(c_ptr_2);
+}
+
+TEST_F(DLMallocTestFixture, alloc_1GB_free_1GB) {
+  char* c_ptr{nullptr};
+  size_t heap_size{1 << 30};
+  size_t size{heap_size - DLMALLOC_BOOKKEEPING};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+  ASSERT_EQ(strat_.get_used() + strat_.get_avail(), heap_size);
+
+  strat_.free(c_ptr);
+}
+

tests/unit_tests/dlmalloc_gtest.hpp

@@ -0,0 +1,62 @@
+/******************************************************************************
+ * Copyright (c) Advanced Micro Devices, Inc. All rights reserved.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *****************************************************************************/
+
+#ifndef ROCSHMEM_DLMALLOC_GTEST_HPP
+#define ROCSHMEM_DLMALLOC_GTEST_HPP
+
+#include "gtest/gtest.h"
+
+#include "../src/memory/heap_memory.hpp"
+#include "../src/memory/hip_allocator.hpp"
+#include "../src/memory/dlmalloc.hpp"
+
+namespace rocshmem {
+
+class DLMallocTestFixture : public ::testing::Test
+{
+    /**
+     * @brief Helper type for heap memory
+     */
+    using HEAP_T = HeapMemory<HIPAllocator>;
+
+    /**
+     * @brief Helper type for allocation strategy
+     */
+    using STRAT_T = DLAllocatorStrategy<HEAP_T>;
+
+  protected:
+    /**
+     * @brief Heap memory object
+     */
+    HEAP_T heap_mem_ {};
+
+    /**
+     * @brief Allocation strategy object
+     */
+    STRAT_T strat_ {&heap_mem_};
+};
+
+} // namespace rocshmem
+
+#endif // ROCSHMEM_DLMALLOC_GTEST_HPP

tests/unit_tests/pow2_bins_gtest.cpp

@@ -26,35 +26,47 @@
 
 using namespace rocshmem;
 
+TEST_F(Pow2BinsTestFixture, used_0_bytes) {
+  ASSERT_EQ(strat_.get_used(), 0);
+}
+
 TEST_F(Pow2BinsTestFixture, alloc_0_bytes) {
   char* c_ptr{nullptr};
   size_t size{0};
+  size_t expected_used{0};
   strat_.alloc(&c_ptr, size);
   ASSERT_EQ(c_ptr, nullptr);
+  ASSERT_EQ(strat_.get_used(), expected_used);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_1_byte) {
   char* c_ptr{nullptr};
   size_t size{1};
+  size_t align_size{ALIGNMENT * (1 + (size - 1) / ALIGNMENT)};
   strat_.alloc(&c_ptr, size);
   ASSERT_NE(c_ptr, nullptr);
 
   size_t min_size{256};
+  ASSERT_LE(align_size, 256); // test fixture won't work for larger values
   auto bins{strat_.get_bins()};
   auto bin{(*bins)[min_size]};
   ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), align_size);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_128_bytes) {
   char* c_ptr{nullptr};
   size_t size{128};
+  size_t align_size{ALIGNMENT * (1 + (size - 1) / ALIGNMENT)};
   strat_.alloc(&c_ptr, size);
   ASSERT_NE(c_ptr, nullptr);
 
   size_t min_size{256};
+  ASSERT_LE(align_size, 256);
   auto bins{strat_.get_bins()};
   auto bin{(*bins)[min_size]};
   ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), align_size);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_256_bytes) {
@@ -66,6 +78,7 @@ TEST_F(Pow2BinsTestFixture, alloc_256_bytes) {
   auto bins{strat_.get_bins()};
   auto bin{(*bins)[size]};
   ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), size);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_512_bytes) {
@@ -77,6 +90,7 @@ TEST_F(Pow2BinsTestFixture, alloc_512_bytes) {
   auto bins{strat_.get_bins()};
   auto bin{(*bins)[size]};
   ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), size);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_513_bytes) {
@@ -89,6 +103,20 @@ TEST_F(Pow2BinsTestFixture, alloc_513_bytes) {
   auto bins{strat_.get_bins()};
   auto bin{(*bins)[min_size]};
   ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), min_size);
+}
+
+TEST_F(Pow2BinsTestFixture, alloc_4095_bytes) {
+  char* c_ptr{nullptr};
+  size_t size{4095};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+
+  size_t min_size{4096};
+  auto bins{strat_.get_bins()};
+  auto bin{(*bins)[min_size]};
+  ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), min_size);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_4KB) {
@@ -100,6 +128,20 @@ TEST_F(Pow2BinsTestFixture, alloc_4KB) {
   auto bins{strat_.get_bins()};
   auto bin{(*bins)[size]};
   ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), size);
+}
+
+TEST_F(Pow2BinsTestFixture, alloc_4097_bytes) {
+  char* c_ptr{nullptr};
+  size_t size{4097};
+  strat_.alloc(&c_ptr, size);
+  ASSERT_NE(c_ptr, nullptr);
+
+  size_t min_size{8192};
+  auto bins{strat_.get_bins()};
+  auto bin{(*bins)[min_size]};
+  ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), min_size);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_128KB) {
@@ -111,6 +153,7 @@ TEST_F(Pow2BinsTestFixture, alloc_128KB) {
   auto bins{strat_.get_bins()};
   auto bin{(*bins)[size]};
   ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), size);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_1GB) {
@@ -122,6 +165,7 @@ TEST_F(Pow2BinsTestFixture, alloc_1GB) {
   auto bins{strat_.get_bins()};
   auto bin{(*bins)[size]};
   ASSERT_EQ(bin.size(), 0);
+  ASSERT_EQ(strat_.get_used(), size);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_256_bytes_X2_free_256_bytes_X2) {
@@ -136,11 +180,13 @@ TEST_F(Pow2BinsTestFixture, alloc_256_bytes_X2_free_256_bytes_X2) {
   auto bins{strat_.get_bins()};
   auto& bin{(*bins)[size]};
   ASSERT_EQ(bin.size(), 0);
+  ASSERT_EQ(strat_.get_used(), 2 * size);
 
   strat_.free(c_ptr_1);
   strat_.free(c_ptr_2);
 
   ASSERT_EQ(bin.size(), 2);
+  ASSERT_EQ(strat_.get_used(), 0);
 }
 
 TEST_F(Pow2BinsTestFixture, alloc_1GB_free_1GB) {
@@ -152,8 +198,10 @@ TEST_F(Pow2BinsTestFixture, alloc_1GB_free_1GB) {
   auto bins{strat_.get_bins()};
   auto& bin{(*bins)[size]};
   ASSERT_EQ(bin.size(), 0);
+  ASSERT_EQ(strat_.get_used(), size);
 
   strat_.free(c_ptr);
 
   ASSERT_EQ(bin.size(), 1);
+  ASSERT_EQ(strat_.get_used(), 0);
 }

tests/unit_tests/single_heap_gtest.cpp

@@ -30,115 +30,157 @@ TEST_F(SingleHeapTestFixture, unallocated_size_check) {
   ASSERT_EQ(single_heap_.get_size(), 1 << 30);
 }
 
-TEST_F(SingleHeapTestFixture, unallocated_avail_check) {
-  ASSERT_EQ(single_heap_.get_avail(), 1 << 30);
-}
-
-TEST_F(SingleHeapTestFixture, unallocated_used_check) {
-  ASSERT_EQ(single_heap_.get_used(), 0);
-}
-
 TEST_F(SingleHeapTestFixture, free_null) {
   void* ptr{nullptr};
   single_heap_.free(ptr);
 }
 
 TEST_F(SingleHeapTestFixture, alloc_0) {
+  // some allocators (e.g. dlmalloc) use memory for internal bookkeeping
+  size_t initial_used{single_heap_.get_used()};
   size_t request_size{0};
   void* ptr{nullptr};
 
   single_heap_.malloc(&ptr, request_size);
   ASSERT_EQ(ptr, nullptr);
-
-  size_t expected_used{request_size};
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  size_t expected_avail{single_heap_.get_size() - expected_used};
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
 
   single_heap_.free(ptr);
-
-  expected_used = 0;
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  expected_avail = single_heap_.get_size();
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
 }
 
 TEST_F(SingleHeapTestFixture, alloc_1) {
+  size_t initial_used{single_heap_.get_used()};
   size_t request_size{1};
   void* ptr{nullptr};
 
   single_heap_.malloc(&ptr, request_size);
   ASSERT_NE(ptr, nullptr);
-
-  size_t expected_used{128};
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  size_t expected_avail{single_heap_.get_size() - expected_used};
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr) & (ALIGNMENT-1), 0);
 
   single_heap_.free(ptr);
-
-  expected_used = 0;
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  expected_avail = single_heap_.get_size();
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
 }
 
 TEST_F(SingleHeapTestFixture, alloc_256) {
+  size_t initial_used{single_heap_.get_used()};
   size_t request_size{256};
   void* ptr{nullptr};
 
   single_heap_.malloc(&ptr, request_size);
   ASSERT_NE(ptr, nullptr);
-
-  size_t expected_used{request_size};
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  size_t expected_avail{single_heap_.get_size() - expected_used};
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr) & (ALIGNMENT-1), 0);
 
   single_heap_.free(ptr);
-
-  expected_used = 0;
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  expected_avail = single_heap_.get_size();
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
 }
 
 TEST_F(SingleHeapTestFixture, alloc_1024) {
+  size_t initial_used{single_heap_.get_used()};
   size_t request_size{1024};
   void* ptr{nullptr};
 
   single_heap_.malloc(&ptr, request_size);
   ASSERT_NE(ptr, nullptr);
-
-  size_t expected_used{request_size};
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  size_t expected_avail{single_heap_.get_size() - expected_used};
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr) & (ALIGNMENT-1), 0);
 
   single_heap_.free(ptr);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
+}
 
-  expected_used = 0;
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  expected_avail = single_heap_.get_size();
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+TEST_F(SingleHeapTestFixture, alloc_1MB) {
+  size_t initial_used{single_heap_.get_used()};
+  size_t request_size{1 << 20};
+  void* ptr{nullptr};
+
+  single_heap_.malloc(&ptr, request_size);
+  ASSERT_NE(ptr, nullptr);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr) & (ALIGNMENT-1), 0);
+
+  single_heap_.free(ptr);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
 }
 
 TEST_F(SingleHeapTestFixture, alloc_4097) {
+  size_t initial_used{single_heap_.get_used()};
   size_t request_size{4097};
   void* ptr{nullptr};
 
   single_heap_.malloc(&ptr, request_size);
   ASSERT_NE(ptr, nullptr);
-
-  size_t expected_used{8192};
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  size_t expected_avail{single_heap_.get_size() - expected_used};
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr) & (ALIGNMENT-1), 0);
 
   single_heap_.free(ptr);
-
-  expected_used = 0;
-  ASSERT_EQ(single_heap_.get_used(), expected_used);
-  expected_avail = single_heap_.get_size();
-  ASSERT_EQ(single_heap_.get_avail(), expected_avail);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
+}
+
+TEST_F(SingleHeapTestFixture, alloc_X2_8191) {
+  size_t initial_used{single_heap_.get_used()};
+  size_t request_size{8191};
+  void* ptr_1{nullptr};
+  void* ptr_2{nullptr};
+
+  single_heap_.malloc(&ptr_1, request_size);
+  ASSERT_NE(ptr_1, nullptr);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr_1) & (ALIGNMENT-1), 0);
+
+  single_heap_.malloc(&ptr_2, request_size);
+  ASSERT_NE(ptr_2, nullptr);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr_2) & (ALIGNMENT-1), 0);
+
+  single_heap_.free(ptr_1);
+  single_heap_.free(ptr_2);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
+}
+
+TEST_F(SingleHeapTestFixture, alloc_X2_free_alloc_free_X2_1MB) {
+  size_t initial_used{single_heap_.get_used()};
+  void* ptr_1{nullptr};
+  void* ptr_2{nullptr};
+  void* ptr_3{nullptr};
+  size_t request_size{1 << 20};
+
+  single_heap_.malloc(&ptr_1, request_size);
+  ASSERT_NE(ptr_1, nullptr);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr_1) & (ALIGNMENT-1), 0);
+
+  single_heap_.malloc(&ptr_2, request_size);
+  ASSERT_NE(ptr_1, nullptr);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr_2) & (ALIGNMENT-1), 0);
+
+  single_heap_.free(ptr_1);
+
+  single_heap_.malloc(&ptr_3, request_size);
+  ASSERT_NE(ptr_3, nullptr);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr_3) & (ALIGNMENT-1), 0);
+
+  single_heap_.free(ptr_3);
+  single_heap_.free(ptr_2);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
+}
+
+TEST_F(SingleHeapTestFixture, alloc_X2_free_alloc_free_X2_63) {
+  size_t initial_used{single_heap_.get_used()};
+  void* ptr_1{nullptr};
+  void* ptr_2{nullptr};
+  void* ptr_3{nullptr};
+  size_t request_size{63};
+
+  single_heap_.malloc(&ptr_1, request_size);
+  ASSERT_NE(ptr_1, nullptr);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr_1) & (ALIGNMENT-1), 0);
+
+  single_heap_.malloc(&ptr_2, request_size);
+  ASSERT_NE(ptr_1, nullptr);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr_2) & (ALIGNMENT-1), 0);
+
+  single_heap_.free(ptr_1);
+
+  single_heap_.malloc(&ptr_3, request_size);
+  ASSERT_NE(ptr_3, nullptr);
+  ASSERT_EQ(reinterpret_cast<uintptr_t>(ptr_3) & (ALIGNMENT-1), 0);
+
+  single_heap_.free(ptr_3);
+  single_heap_.free(ptr_2);
+  ASSERT_EQ(single_heap_.get_used(), initial_used);
 }