Fix free memory calculation.

base/sys_info_unittest.cc

 // Copyright (c) 2012 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 <stdint.h>
 
 #include "base/environment.h"
 #include "base/files/file_util.h"
+#include "base/process/process_metrics.h"
 #include "base/sys_info.h"
 #include "base/threading/platform_thread.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/platform_test.h"
 
 typedef PlatformTest SysInfoTest;
 using base::FilePath;
 
 TEST_F(SysInfoTest, NumProcs) {
   // We aren't actually testing that it's correct, just that it's sane.
   EXPECT_GE(base::SysInfo::NumberOfProcessors(), 1);
 }
 
 TEST_F(SysInfoTest, AmountOfMem) {
   // We aren't actually testing that it's correct, just that it's sane.
   EXPECT_GT(base::SysInfo::AmountOfPhysicalMemory(), 0);
   EXPECT_GT(base::SysInfo::AmountOfPhysicalMemoryMB(), 0);
   // The maxmimal amount of virtual memory can be zero which means unlimited.
   EXPECT_GE(base::SysInfo::AmountOfVirtualMemory(), 0);
 }
 
+#if defined(OS_LINUX) || defined(OS_ANDROID)
+TEST_F(SysInfoTest, AmountOfAvailablePhysicalMemory) {
+  // Note: info is in _K_bytes.
+  base::SystemMemoryInfoKB info;
+  ASSERT_TRUE(base::GetSystemMemoryInfo(&info));
+  EXPECT_GT(info.free, 0);
+
+  if (info.available != 0) {
+    // If there is MemAvailable from kernel.
+    EXPECT_LT(info.available, info.total);
+    const int64_t amount = base::SysInfo::AmountOfAvailablePhysicalMemory(info);
+    // We aren't actually testing that it's correct, just that it's sane.
+    EXPECT_GT(amount, info.free * 1024);
+    EXPECT_LT(amount, info.available * 1024);

[Primiano Tucci (use gerrit), 2017/03/08 12:36:41]

shouldn't this be s/LT/LE/ ?

[Michael K. (Yandex Team), 2017/03/09 07:21:15]

Only when active file-backed memory is zero (what seems unreal). That's by our
own definition: see base/sys_info_linux.cc.  But if you think that can be real -
I'll s/LT/LE.

[Primiano Tucci (use gerrit), 2017/03/09 10:24:03]

Ah you are right, forgot about the -active_file part.  

+    // Simulate as if there is no MemAvailable.
+    info.available = 0;
+  }
+
+  // There is no MemAvailable. Check the fallback logic.
+  const int64_t amount = base::SysInfo::AmountOfAvailablePhysicalMemory(info);
+  // We aren't actually testing that it's correct, just that it's sane.
+  EXPECT_GT(amount, info.free * 1024);
+  EXPECT_LT(amount, info.total * 1024);
+}
+#endif  // defined(OS_LINUX) || defined(OS_ANDROID)
+
 TEST_F(SysInfoTest, AmountOfFreeDiskSpace) {
   // We aren't actually testing that it's correct, just that it's sane.
   FilePath tmp_path;
   ASSERT_TRUE(base::GetTempDir(&tmp_path));
   EXPECT_GE(base::SysInfo::AmountOfFreeDiskSpace(tmp_path), 0)
             << tmp_path.value();
 }
 
 TEST_F(SysInfoTest, AmountOfTotalDiskSpace) {
   // We aren't actually testing that it's correct, just that it's sane.
@@ skipping 118 matching lines @@
   const char* kLsbRelease1 = "CHROMEOS_RELEASE_BOARD=Glimmer\n";
   base::SysInfo::SetChromeOSVersionInfoForTest(kLsbRelease1, base::Time());
   EXPECT_EQ("glimmer", base::SysInfo::GetStrippedReleaseBoard());
 
   const char* kLsbRelease2 = "CHROMEOS_RELEASE_BOARD=glimmer-signed-mp-v4keys";
   base::SysInfo::SetChromeOSVersionInfoForTest(kLsbRelease2, base::Time());
   EXPECT_EQ("glimmer", base::SysInfo::GetStrippedReleaseBoard());
 }
 
 #endif  // OS_CHROMEOS