Fix free memory calculation.

base/process/process_metrics_ios.cc

 // Copyright (c) 2013 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/process/process_metrics.h"
 
 #include <limits.h>
 #include <mach/task.h>
 #include <stddef.h>
 
 #include "base/logging.h"
+#include "base/mac/scoped_mach_port.h"
 #include "base/memory/ptr_util.h"
 
 namespace base {
 
 namespace {
 
 bool GetTaskInfo(task_basic_info_64* task_info_data) {
   mach_msg_type_number_t count = TASK_BASIC_INFO_64_COUNT;
   kern_return_t kr = task_info(mach_task_self(),
                                TASK_BASIC_INFO_64,
                                reinterpret_cast<task_info_t>(task_info_data),
                                &count);
   return kr == KERN_SUCCESS;
 }
 
 }  // namespace
 
-SystemMemoryInfoKB::SystemMemoryInfoKB() : total(0), free(0) {}
+SystemMemoryInfoKB::SystemMemoryInfoKB()
+    : total(0), free(0), speculative(0), file_backed(0), purgeable(0) {}

[brucedawson, 2017/03/09 19:17:52]

Consider zeroing these where the variables are declared instead of here - newly
available C++ feature that has been approved for use in Chromium. This would
reduce duplication across platform-specific source files.

[Michael K. (Yandex Team), 2017/03/10 15:53:57]

Done.

 
 SystemMemoryInfoKB::SystemMemoryInfoKB(const SystemMemoryInfoKB& other) =
     default;
 
 ProcessMetrics::ProcessMetrics(ProcessHandle process) {}
 
 ProcessMetrics::~ProcessMetrics() {}
 
 // static
 std::unique_ptr<ProcessMetrics> ProcessMetrics::CreateProcessMetrics(
@@ skipping 44 matching lines @@
 size_t GetPageSize() {
   return getpagesize();
 }
 
 // Bytes committed by the system.
 size_t GetSystemCommitCharge() {
   NOTIMPLEMENTED();
   return 0;
 }
 
-// Bytes committed by the system.
 bool GetSystemMemoryInfo(SystemMemoryInfoKB* meminfo) {
-  // Unimplemented. Must enable unittest for IOS when this gets implemented.
-  NOTIMPLEMENTED();
-  return false;
+  struct host_basic_info hostinfo;
+  mach_msg_type_number_t count = HOST_BASIC_INFO_COUNT;
+  base::mac::ScopedMachSendRight host(mach_host_self());
+  int result = host_info(host.get(), HOST_BASIC_INFO,
+                         reinterpret_cast<host_info_t>(&hostinfo), &count);
+  if (result != KERN_SUCCESS)
+    return false;
+
+  DCHECK_EQ(HOST_BASIC_INFO_COUNT, count);
+  meminfo->total = static_cast<int>(hostinfo.max_mem / 1024);
+
+  vm_statistics64_data_t vm_info;
+  count = HOST_VM_INFO64_COUNT;
+
+  if (host_statistics64(host.get(), HOST_VM_INFO64,
+                        reinterpret_cast<host_info64_t>(&vm_info),
+                        &count) != KERN_SUCCESS) {
+    return false;
+  }
+  DCHECK_EQ(HOST_VM_INFO64_COUNT, count);
+
+  meminfo->free = static_cast<int>(
+      (vm_info.free_count - vm_info.speculative_count) * PAGE_SIZE / 1024);
+  meminfo->speculative =
+      static_cast<int>(vm_info.speculative_count * PAGE_SIZE / 1024);
+  meminfo->file_backed =
+      static_cast<int>(vm_info.external_page_count * PAGE_SIZE / 1024);
+  meminfo->purgeable =
+      static_cast<int>(vm_info.purgeable_count * PAGE_SIZE / 1024);
+
+  return true;
 }
 
 }  // namespace base