[iOS] Upstream //ios/chrome/browser/memory

ios/chrome/browser/memory/memory_metrics.cc

+// Copyright 2014 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 "ios/chrome/browser/memory/memory_metrics.h"
+
+#include <mach/mach.h>
+
+#include "base/logging.h"
+#include "base/process/process_handle.h"
+#include "base/process/process_metrics.h"
+
+#ifdef ARCH_CPU_64_BITS
+#define cr_vm_region vm_region_64
+#else
+#define cr_vm_region vm_region
+#endif
+
+namespace {
+// The number of pages returned by host_statistics and vm_region are a count
+// of pages of 4096 bytes even when running on arm64 but the constants that
+// are exposed (vm_page_size, VM_PAGE_SIZE, host_page_size) are all equals to
+// 16384 bytes. So we define our own constant here to convert from page count
+// to bytes.
+const uint64_t kVMPageSize = 4096;
+}
+
+namespace memory_util {
+
+uint64 GetFreePhysicalBytes() {
+  vm_statistics_data_t vmstat;
+  mach_msg_type_number_t count = HOST_VM_INFO_COUNT;
+  kern_return_t result =
+      host_statistics(mach_host_self(), HOST_VM_INFO,
+                      reinterpret_cast<host_info_t>(&vmstat), &count);
+  if (result != KERN_SUCCESS) {
+    LOG(ERROR) << "Calling host_statistics failed.";
+    return 0;
+  }
+  return vmstat.free_count * kVMPageSize;
+}
+
+uint64 GetRealMemoryUsedInBytes() {
+  base::ProcessHandle process_handle = base::GetCurrentProcessHandle();
+  scoped_ptr<base::ProcessMetrics> process_metrics(
+      base::ProcessMetrics::CreateProcessMetrics(process_handle));
+  return static_cast<uint64>(process_metrics->GetWorkingSetSize());
+}
+
+uint64 GetDirtyVMBytes() {
+  // Iterate over all VM regions and sum their dirty pages.
+  unsigned int total_dirty_pages = 0;
+  vm_size_t vm_size = 0;
+  kern_return_t result;
+  for (vm_address_t address = MACH_VM_MIN_ADDRESS;; address += vm_size) {
+    vm_region_extended_info_data_t info;
+    mach_msg_type_number_t info_count = VM_REGION_EXTENDED_INFO_COUNT;
+    mach_port_t object_name;
+    result = cr_vm_region(
+        mach_task_self(), &address, &vm_size, VM_REGION_EXTENDED_INFO,
+        reinterpret_cast<vm_region_info_t>(&info), &info_count, &object_name);
+    if (result == KERN_INVALID_ADDRESS) {
+      // The end of the address space has been reached.
+      break;
+    } else if (result != KERN_SUCCESS) {
+      LOG(ERROR) << "Calling vm_region failed with code: " << result;
+      break;
+    } else {
+      total_dirty_pages += info.pages_dirtied;
+    }
+  }
+  return total_dirty_pages * kVMPageSize;
+}
+
+uint64 GetInternalVMBytes() {
+  task_vm_info_data_t task_vm_info;
+  mach_msg_type_number_t count = TASK_VM_INFO_COUNT;
+  kern_return_t result =
+      task_info(mach_task_self(), TASK_VM_INFO,
+                reinterpret_cast<task_info_t>(&task_vm_info), &count);
+  if (result != KERN_SUCCESS) {
+    LOG(ERROR) << "Calling task_info failed.";
+    return 0;
+  }
+
+  return static_cast<uint64>(task_vm_info.internal);
+}
+
+}  // namespace memory_util