tracing: Reduce memory usage of heap_profiler_allocation_register_unittest.cc

base/trace_event/heap_profiler_allocation_register_unittest.cc

 // Copyright 2015 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/trace_event/heap_profiler_allocation_register.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/process/process_metrics.h"
 #include "base/trace_event/heap_profiler_allocation_context.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 namespace trace_event {
 
 class AllocationRegisterTest : public testing::Test {
  public:
-  static const uint32_t kNumBuckets = AllocationRegister::kNumBuckets;
+  // Use a lower number of cells for unittests to avoid reserving a virtual
+  // region which is too big.
+  static const uint32_t kNumCellsForTesting =
+      AllocationRegister::kNumBuckets + 100;
 
   // Returns the number of cells that the |AllocationRegister| can store per
   // system page.
   size_t GetNumCellsPerPage() {
     return GetPageSize() / sizeof(AllocationRegister::Cell);
   }
 
   uint32_t GetHighWaterMark(const AllocationRegister& reg) {
     return reg.next_unused_cell_;
   }
@@ skipping 19 matching lines @@
 size_t SumAllSizes(const AllocationRegister& reg) {
   size_t sum = 0;
 
   for (auto i : reg)
     sum += i.size;
 
   return sum;
 }
 
 TEST_F(AllocationRegisterTest, InsertRemove) {
-  AllocationRegister reg;
+  AllocationRegister reg(kNumCellsForTesting);
   AllocationContext ctx;
 
   // Zero-sized allocations should be discarded.
   reg.Insert(reinterpret_cast<void*>(1), 0, ctx);
 
   EXPECT_EQ(0u, OrAllAddresses(reg));
 
   reg.Insert(reinterpret_cast<void*>(1), 1, ctx);
 
   EXPECT_EQ(1u, OrAllAddresses(reg));
@@ skipping 13 matching lines @@
   reg.Remove(reinterpret_cast<void*>(4));
 
   EXPECT_EQ(1u, OrAllAddresses(reg));
 
   reg.Remove(reinterpret_cast<void*>(1));
 
   EXPECT_EQ(0u, OrAllAddresses(reg));
 }
 
 TEST_F(AllocationRegisterTest, DoubleFreeIsAllowed) {
-  AllocationRegister reg;
+  AllocationRegister reg(kNumCellsForTesting);
   AllocationContext ctx;
 
   reg.Insert(reinterpret_cast<void*>(1), 1, ctx);
   reg.Insert(reinterpret_cast<void*>(2), 1, ctx);
   reg.Remove(reinterpret_cast<void*>(1));
   reg.Remove(reinterpret_cast<void*>(1));  // Remove for the second time.
   reg.Remove(reinterpret_cast<void*>(4));  // Remove never inserted address.
 
   EXPECT_EQ(2u, OrAllAddresses(reg));
 }
 
 TEST_F(AllocationRegisterTest, DoubleInsertOverwrites) {
-  // TODO(ruuda): Although double insert happens in practice, it should not.
-  // Find out the cause and ban double insert if possible.
-  AllocationRegister reg;
+  AllocationRegister reg(kNumCellsForTesting);
   AllocationContext ctx;
   StackFrame frame1 = StackFrame::FromTraceEventName("Foo");
   StackFrame frame2 = StackFrame::FromTraceEventName("Bar");
 
   ctx.backtrace.frame_count = 1;
 
   ctx.backtrace.frames[0] = frame1;
   reg.Insert(reinterpret_cast<void*>(1), 11, ctx);
 
   {
@@ skipping 13 matching lines @@
     EXPECT_EQ(frame2, elem.context.backtrace.frames[0]);
     EXPECT_EQ(13u, elem.size);
     EXPECT_EQ(reinterpret_cast<void*>(1), elem.address);
   }
 }
 
 // Check that even if more entries than the number of buckets are inserted, the
 // register still behaves correctly.
 TEST_F(AllocationRegisterTest, InsertRemoveCollisions) {
   size_t expected_sum = 0;
-  AllocationRegister reg;
+  AllocationRegister reg(kNumCellsForTesting);
   AllocationContext ctx;
 
   // By inserting 100 more entries than the number of buckets, there will be at
-  // least 100 collisions.
-  for (uintptr_t i = 1; i <= kNumBuckets + 100; i++) {
+  // least 100 collisions (100 = kNumCellsForTesting - kNumBuckets).
+  for (uintptr_t i = 1; i <= kNumCellsForTesting; i++) {
     size_t size = i % 31;
     expected_sum += size;
     reg.Insert(reinterpret_cast<void*>(i), size, ctx);
 
     // Don't check the sum on every iteration to keep the test fast.
     if (i % (1 << 14) == 0)
       EXPECT_EQ(expected_sum, SumAllSizes(reg));
   }
 
   EXPECT_EQ(expected_sum, SumAllSizes(reg));
 
-  for (uintptr_t i = 1; i <= kNumBuckets + 100; i++) {
+  for (uintptr_t i = 1; i <= kNumCellsForTesting; i++) {
     size_t size = i % 31;
     expected_sum -= size;
     reg.Remove(reinterpret_cast<void*>(i));
 
     if (i % (1 << 14) == 0)
       EXPECT_EQ(expected_sum, SumAllSizes(reg));
   }
 
   EXPECT_EQ(expected_sum, SumAllSizes(reg));
 }
 
 // The previous tests are not particularly good for testing iterators, because
 // elements are removed and inserted in the same order, meaning that the cells
 // fill up from low to high index, and are then freed from low to high index.
 // This test removes entries in a different order, to ensure that the iterator
 // skips over the freed cells properly. Then insert again to ensure that the
 // free list is utilised properly.
 TEST_F(AllocationRegisterTest, InsertRemoveRandomOrder) {
   size_t expected_sum = 0;
-  AllocationRegister reg;
+  AllocationRegister reg(kNumCellsForTesting);
   AllocationContext ctx;
 
   uintptr_t generator = 3;
   uintptr_t prime = 1013;
   uint32_t initial_water_mark = GetHighWaterMark(reg);
 
   for (uintptr_t i = 2; i < prime; i++) {
     size_t size = i % 31 + 1;
     expected_sum += size;
     reg.Insert(reinterpret_cast<void*>(i), size, ctx);
@@ skipping 20 matching lines @@
   ASSERT_EQ(prime - 2, GetHighWaterMark(reg) - initial_water_mark);
 
   // Inserting one more entry should use a fresh cell again.
   reg.Insert(reinterpret_cast<void*>(prime), 1, ctx);
   ASSERT_EQ(prime - 1, GetHighWaterMark(reg) - initial_water_mark);
 }
 
 TEST_F(AllocationRegisterTest, ChangeContextAfterInsertion) {
   using Allocation = AllocationRegister::Allocation;
   const char kStdString[] = "std::string";
-  AllocationRegister reg;
+  AllocationRegister reg(kNumCellsForTesting);
   AllocationContext ctx;
 
   reg.Insert(reinterpret_cast<void*>(17), 1, ctx);
   reg.Insert(reinterpret_cast<void*>(19), 2, ctx);
   reg.Insert(reinterpret_cast<void*>(23), 3, ctx);
 
   // Looking up addresses that were not inserted should return null.
   // A null pointer lookup is a valid thing to do.
   EXPECT_EQ(nullptr, reg.Get(nullptr));
   EXPECT_EQ(nullptr, reg.Get(reinterpret_cast<void*>(13)));
@@ skipping 51 matching lines @@
   const size_t cells_per_page = GetNumCellsPerPage();
 
   ASSERT_DEATH(for (size_t j = 0; j < cells_per_page; j++) {
     reg.Insert(reinterpret_cast<void*>(i + j), 1, ctx);
   }, "");
 }
 #endif
 
 }  // namespace trace_event
 }  // namespace base