1 files changed, 99 insertions, 0 deletions
diff --git a/test/syscalls/linux/memory_accounting.cc b/test/syscalls/linux/memory_accounting.cc
new file mode 100644
index 000000000..b4b680c34
--- /dev/null
+++ b/test/syscalls/linux/memory_accounting.cc
@@ -0,0 +1,99 @@
+// Copyright 2018 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <sys/mman.h>
+#include <map>
+
+#include "gtest/gtest.h"
+#include "gtest/gtest.h"
+#include "absl/strings/match.h"
+#include "absl/strings/numbers.h"
+#include "absl/strings/str_format.h"
+#include "absl/strings/str_split.h"
+#include "test/util/fs_util.h"
+#include "test/util/posix_error.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+namespace {
+
+using ::absl::StrFormat;
+
+// AnonUsageFromMeminfo scrapes the current anonymous memory usage from
+// /proc/meminfo and returns it in bytes.
+PosixErrorOr<uint64_t> AnonUsageFromMeminfo() {
+  ASSIGN_OR_RETURN_ERRNO(auto meminfo, GetContents("/proc/meminfo"));
+  std::vector<std::string> lines(absl::StrSplit(meminfo, '\n'));
+
+  // Try to find AnonPages line, the format is AnonPages:\\s+(\\d+) kB\n.
+  for (const auto& line : lines) {
+    if (!absl::StartsWith(line, "AnonPages:")) {
+      continue;
+    }
+
+    std::vector<std::string> parts(
+        absl::StrSplit(line, ' ', absl::SkipEmpty()));
+    if (parts.size() == 3) {
+      // The size is the second field, let's try to parse it as a number.
+      ASSIGN_OR_RETURN_ERRNO(auto anon_kb, Atoi<uint64_t>(parts[1]));
+      return anon_kb * 1024;
+    }
+
+    return PosixError(EINVAL, "AnonPages field in /proc/meminfo was malformed");
+  }
+
+  return PosixError(EINVAL, "AnonPages field not found in /proc/meminfo");
+}
+
+TEST(MemoryAccounting, AnonAccountingPreservedOnSaveRestore) {
+  // This test isn't meaningful on Linux. /proc/meminfo reports system-wide
+  // memory usage, which can change arbitrarily in Linux from other activity on
+  // the machine. In gvisor, this test is the only thing running on the
+  // "machine", so values in /proc/meminfo accurately reflect the memory used by
+  // the test.
+  SKIP_IF(!IsRunningOnGvisor());
+
+  uint64_t anon_initial = ASSERT_NO_ERRNO_AND_VALUE(AnonUsageFromMeminfo());
+
+  // Cause some anonymous memory usage.
+  uint64_t map_bytes = Megabytes(512);
+  char* mem =
+      static_cast<char*>(mmap(nullptr, map_bytes, PROT_READ | PROT_WRITE,
+                              MAP_POPULATE | MAP_ANON | MAP_PRIVATE, -1, 0));
+  ASSERT_NE(mem, MAP_FAILED)
+      << "Map failed, errno: " << errno << " (" << strerror(errno) << ").";
+
+  // Write something to each page to prevent them from being decommited on
+  // S/R. Zero pages are dropped on save.
+  for (uint64_t i = 0; i < map_bytes; i += kPageSize) {
+    mem[i] = 'a';
+  }
+
+  uint64_t anon_after_alloc = ASSERT_NO_ERRNO_AND_VALUE(AnonUsageFromMeminfo());
+  EXPECT_THAT(anon_after_alloc,
+              EquivalentWithin(anon_initial + map_bytes, 0.03));
+
+  // We have many implicit S/R cycles from scraping /proc/meminfo throughout the
+  // test, but throw an explicit S/R in here as well.
+  MaybeSave();
+
+  // Usage should remain the same across S/R.
+  uint64_t anon_after_sr = ASSERT_NO_ERRNO_AND_VALUE(AnonUsageFromMeminfo());
+  EXPECT_THAT(anon_after_sr, EquivalentWithin(anon_after_alloc, 0.03));
+}
+
+}  // namespace
+}  // namespace testing
+}  // namespace gvisor