startop: Add iorap.stress.memory tool to test system with less RAM

//

// Copyright (C) 2020 The Android Open Source Project

//

// 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.

//

cc_binary {

  name: "iorap.stress.memory",

  srcs: ["main_memory.cc"],

  cflags: [

      "-Wall",

      "-Wextra",

      "-Werror",

      "-Wno-unused-parameter"

  ],

  shared_libs: [

      "libbase"

  ],

  host_supported: true,

}

//

// Copyright (C) 2020 The Android Open Source Project

//

// 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 <chrono>

#include <fstream>

#include <iostream>

#include <random>

#include <string>

#include <string.h>

#include <stdlib.h>

#include <sys/mman.h>

#include <android-base/parseint.h>

static constexpr size_t kBytesPerMb = 1048576;

const size_t kMemoryAllocationSize = 2 * 1024 * kBytesPerMb;

#define USE_MLOCKALL 0

std::string GetProcessStatus(const char* key) {

  // Build search pattern of key and separator.

  std::string pattern(key);

  pattern.push_back(':');

  // Search for status lines starting with pattern.

  std::ifstream fs("/proc/self/status");

  std::string line;

  while (std::getline(fs, line)) {

    if (strncmp(pattern.c_str(), line.c_str(), pattern.size()) == 0) {

      // Skip whitespace in matching line (if any).

      size_t pos = line.find_first_not_of(" \t", pattern.size());

      if (pos == std::string::npos) {

        break;

      }

      return std::string(line, pos);

    }

  }

  return "<unknown>";

}

int main(int argc, char** argv) {

  size_t allocationSize = 0;

  if (argc >= 2) {

    if (!android::base::ParseUint(argv[1], /*out*/&allocationSize)) {

      std::cerr << "Failed to parse the allocation size (must be 0,MAX_SIZE_T)" << std::endl;

      return 1;

    }

  } else {

    allocationSize = kMemoryAllocationSize;

  }

  void* mem = malloc(allocationSize);

  if (mem == nullptr) {

    std::cerr << "Malloc failed" << std::endl;

    return 1;

  }

  volatile int* imem = static_cast<int *>(mem);  // don't optimize out memory usage

  size_t imemCount = allocationSize / sizeof(int);

  std::cout << "Allocated " << allocationSize << " bytes" << std::endl;

  auto seed = std::chrono::high_resolution_clock::now().time_since_epoch().count();

  std::mt19937 mt_rand(seed);

  size_t randPrintCount = 10;

  // Write random numbers:

  // * Ensures each page is resident

  // * Avoids zeroed out pages (zRAM)

  // * Avoids same-page merging

  for (size_t i = 0; i < imemCount; ++i) {

    imem[i] = mt_rand();

    if (i < randPrintCount) {

      std::cout << "Generated random value: " << imem[i] << std::endl;

    }

  }

#if USE_MLOCKALL

  /*

   * Lock all pages from the address space of this process.

   */

  if (mlockall(MCL_CURRENT | MCL_FUTURE) != 0) {

    std::cerr << "Mlockall failed" << std::endl;

    return 1;

  }

#else

  // Use mlock because of the predictable VmLck size.

  // Using mlockall tends to bring in anywhere from 2-2.5GB depending on the device.

  if (mlock(mem, allocationSize) != 0) {

    std::cerr << "Mlock failed" << std::endl;

    return 1;

  }

#endif

  // Validate memory is actually resident and locked with:

  // $> cat /proc/$(pidof iorap.stress.memory)/status | grep VmLck

  std::cout << "Locked memory (VmLck) = " << GetProcessStatus("VmLck") << std::endl;

  std::cout << "Press any key to terminate" << std::endl;

  int any_input;

  std::cin >> any_input;

  std::cout << "Terminating..." << std::endl;

  munlockall();

  free(mem);

  return 0;

}