Create base::win::MemoryPressureMonitor class.

base/win/memory_pressure_monitor_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/win/memory_pressure_monitor.h"
+
+#include "base/basictypes.h"
+#include "base/memory/memory_pressure_listener.h"
+#include "base/message_loop/message_loop.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace win {
+
+namespace {
+
+struct PressureSettings {
+  int phys;
+  int virt;
+  MemoryPressureListener::MemoryPressureLevel level;
+};
+
+}  // namespace
+
+// This is outside of the anonymous namespace so that it can be seen as a friend
+// to the monitor class.
+class TestMemoryPressureMonitor : public MemoryPressureMonitor {
+ public:
+  using MemoryPressureMonitor::CalculateCurrentPressureLevel;
+  using MemoryPressureMonitor::CheckMemoryPressure;
+
+  static const DWORDLONG k4GB = 4ull * 1024 * 1024 * 1024;
+
+  TestMemoryPressureMonitor() {
+    // Disable any timers which are going on and set a special memory reporting
+    // function.
+    StopObserving();
+  }
+
+  virtual ~TestMemoryPressureMonitor() {}
+
+  MOCK_METHOD1(OnMemoryPressure,
+               void(MemoryPressureListener::MemoryPressureLevel level));
+
+  // Sets up the memory status to reflect the provided loads.
+  void SetMemoryLoad(int phys_load_pct, int virt_load_pct) {
+    mem_status_.dwMemoryLoad = static_cast<DWORD>(phys_load_pct);
+    mem_status_.ullTotalPhys = k4GB;
+    mem_status_.ullAvailPhys = (k4GB * (100 - phys_load_pct)) / 100;
+    mem_status_.ullTotalPageFile = k4GB;
+    mem_status_.ullAvailPageFile = k4GB;
+    mem_status_.ullTotalVirtual = k4GB;
+    mem_status_.ullAvailVirtual = (k4GB * (100 - virt_load_pct)) / 100;
+  }
+
+  // Sets up the memory status to reflect the provided absolute memory left.
+  // This uses quite small total memory quantities so that the absolute memory
+  // limits have a chance to kick in.
+  void SetMemoryFree(int phys_left_mb) {
+    static DWORDLONG kMBBytes = 1024 * 1024;
+
+    // Figure out an amount of memory that makes sense for the desired
+    // quantities of memory to be left.
+    DWORDLONG total_mb = 64;  // Minimum of 64MB.
+    while (total_mb < phys_left_mb)
+      total_mb *= 2;
+    DWORDLONG total_bytes = total_mb * kMBBytes;
+
+    mem_status_.ullTotalPhys = total_bytes;
+    mem_status_.ullAvailPhys =
+        static_cast<DWORDLONG>(phys_left_mb) * kMBBytes;
+    mem_status_.ullTotalPageFile = total_bytes;
+    mem_status_.ullAvailPageFile = total_bytes;
+    mem_status_.ullTotalVirtual = k4GB;
+    mem_status_.ullAvailVirtual = k4GB;
+    mem_status_.dwMemoryLoad = static_cast<DWORD>(
+        100 * (mem_status_.ullTotalPhys - mem_status_.ullAvailPhys) /
+        mem_status_.ullTotalPhys);
+  }
+
+ private:
+  bool GetSystemMemoryStatus(MEMORYSTATUSEX* mem_status) override {
+    // Simply copy the memory status set by the test fixture.
+    *mem_status = mem_status_;
+    return true;
+  }
+
+  MEMORYSTATUSEX mem_status_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestMemoryPressureMonitor);
+};
+
+// Tests the fundamental direct calculation of memory pressure.
+TEST(WinMemoryPressureMonitorTest, CalculateCurrentMemoryPressureLevel) {
+  base::MessageLoopForUI message_loop;
+  TestMemoryPressureMonitor monitor;
+
+  // A bunch of memory load settings and the expected memory pressure.
+  const PressureSettings kLoadSettings[] = {
+      { 10, 10, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE },
+      { 40, 40, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE },
+      { 65, 10, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE },
+      { 65, 65, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE },
+      { 98, 10, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL },
+      { 98, 65, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL },
+      { 98, 98, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL },
+#if !defined(ARCH_CPU_64_BITS)
+      // This simulates low virtual memory, which is only applicable on
+      // 32-bit systems.
+      { 10, 65, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE },
+      { 10, 98, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL },
+      { 65, 98, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL },
+#endif  // !defined(ARCH_CPU_64_BITS)
+  };
+
+  for (const PressureSettings& setting : kLoadSettings) {
+    monitor.SetMemoryLoad(setting.phys, setting.virt);
+    EXPECT_EQ(setting.level, monitor.CalculateCurrentPressureLevel());
+  }
+
+  // A bunch of free memory settings and the expected memory pressure. The
+  // 'virt' parameter is ignored, thus zeroed.
+  const PressureSettings kFreeSettings[] = {
+      { 500, 0, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE },
+      { 250, 0, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE },
+      { 250, 0, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE },
+      { 50, 0, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL },
+      { 50, 0, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL },
+      { 50, 0, MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL },
+  };
+
+  for (const PressureSettings& setting : kFreeSettings) {
+    monitor.SetMemoryFree(setting.phys);
+    EXPECT_EQ(setting.level, monitor.CalculateCurrentPressureLevel());
+  }
+}
+
+// This test tests the various transition states from memory pressure, looking
+// for the correct behavior on event reposting as well as state updates.
+TEST(WinMemoryPressureMonitorTest, CheckMemoryPressure) {
+  base::MessageLoopForUI message_loop;
+  testing::StrictMock<TestMemoryPressureMonitor> monitor;

[grt (UTC plus 2), 2015/05/06 16:31:09]

to force Google Mock to evaluate all expectation for each little test here, you
need to either ensure that the mock is deleted and recreated for each micro test
(you can introduce scopes{} for this) or call
Mock::VerifyAndClearExpectations(&monitor); after each micro test.

[chrisha, 2015/05/06 16:59:04]

Ooh, didn't know about VerifyAndClearExpectations, thanks!

+  MemoryPressureListener listener(
+      base::Bind(&TestMemoryPressureMonitor::OnMemoryPressure,
+                 base::Unretained(&monitor)));
+
+  // Checking the memory pressure at 0% load should not produce any
+  // events.
+  monitor.SetMemoryLoad(0, 0);
+  monitor.CheckMemoryPressure();
+  message_loop.RunUntilIdle();
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE,
+            monitor.GetCurrentPressureLevel());
+
+  // Setting the memory level to 80% should produce a moderate pressure level.
+  EXPECT_CALL(monitor,
+              OnMemoryPressure(MemoryPressureListener::
+                                   MEMORY_PRESSURE_LEVEL_MODERATE));
+  monitor.SetMemoryLoad(80, 80);
+  monitor.CheckMemoryPressure();
+  message_loop.RunUntilIdle();
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+            monitor.GetCurrentPressureLevel());
+
+  // Check that the event gets reposted after a while.
+  for (int i = 0; i < monitor.kModeratePressureCooldownCycles; ++i) {
+    if (i + 1 == monitor.kModeratePressureCooldownCycles) {
+      EXPECT_CALL(monitor,
+                OnMemoryPressure(MemoryPressureListener::
+                                     MEMORY_PRESSURE_LEVEL_MODERATE));
+    }
+    monitor.CheckMemoryPressure();
+    message_loop.RunUntilIdle();
+    EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+              monitor.GetCurrentPressureLevel());
+  }
+
+  // Setting the memory usage to 99% should produce critical levels.
+  EXPECT_CALL(monitor,
+              OnMemoryPressure(MemoryPressureListener::
+                                   MEMORY_PRESSURE_LEVEL_CRITICAL));
+  monitor.SetMemoryLoad(99, 99);
+  monitor.CheckMemoryPressure();
+  message_loop.RunUntilIdle();
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL,
+            monitor.GetCurrentPressureLevel());
+
+  // Calling it again should immediately produce a second call.
+  EXPECT_CALL(monitor,
+              OnMemoryPressure(MemoryPressureListener::
+                                   MEMORY_PRESSURE_LEVEL_CRITICAL));
+  monitor.CheckMemoryPressure();
+  message_loop.RunUntilIdle();
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL,
+            monitor.GetCurrentPressureLevel());
+
+  // When lowering the pressure again there should be a notification and the
+  // pressure should go back to moderate.
+  EXPECT_CALL(monitor,
+              OnMemoryPressure(MemoryPressureListener::
+                                   MEMORY_PRESSURE_LEVEL_MODERATE));
+  monitor.SetMemoryLoad(80, 80);
+  monitor.CheckMemoryPressure();
+  message_loop.RunUntilIdle();
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+            monitor.GetCurrentPressureLevel());
+
+  // Check that the event gets reposted after a while.
+  for (int i = 0; i < monitor.kModeratePressureCooldownCycles; ++i) {
+    if (i + 1 == monitor.kModeratePressureCooldownCycles) {
+      EXPECT_CALL(monitor,
+                OnMemoryPressure(MemoryPressureListener::
+                                     MEMORY_PRESSURE_LEVEL_MODERATE));
+    }
+    monitor.CheckMemoryPressure();
+    message_loop.RunUntilIdle();
+    EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+              monitor.GetCurrentPressureLevel());
+  }
+
+  // Going down to no pressure should not produce an notification.
+  monitor.SetMemoryLoad(0, 0);
+  monitor.CheckMemoryPressure();
+  message_loop.RunUntilIdle();
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE,
+            monitor.GetCurrentPressureLevel());
+}
+
+}  // namespace win
+}  // namespace base