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// Copyright 2016 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.h"
#include <mach/mach.h>
#include "base/feature_list.h"
#include "base/mac/mach_logging.h"
namespace base {
// Enables backgrounding hidden renderers on Mac.
const Feature kMacAllowBackgroundingProcesses{"MacAllowBackgroundingProcesses",
FEATURE_DISABLED_BY_DEFAULT};
bool Process::CanBackgroundProcesses() {
return FeatureList::IsEnabled(kMacAllowBackgroundingProcesses);
}
bool Process::IsProcessBackgrounded(PortProvider* port_provider) const {
DCHECK(IsValid());
if (port_provider == nullptr || !CanBackgroundProcesses())
return false;
mach_port_t task_port = port_provider->TaskForPid(Pid());
if (task_port == TASK_NULL)
return false;
task_category_policy_data_t category_policy;
mach_msg_type_number_t task_info_count = TASK_CATEGORY_POLICY_COUNT;
boolean_t get_default = FALSE;
kern_return_t result =
task_policy_get(task_port, TASK_CATEGORY_POLICY,
reinterpret_cast<task_policy_t>(&category_policy),
&task_info_count, &get_default);
MACH_LOG_IF(ERROR, result != KERN_SUCCESS, result)
<< "task_policy_get TASK_CATEGORY_POLICY";
if (result == KERN_SUCCESS && get_default == FALSE) {
return category_policy.role == TASK_BACKGROUND_APPLICATION;
}
return false;
}
bool Process::SetProcessBackgrounded(PortProvider* port_provider,
bool background) {
DCHECK(IsValid());
if (port_provider == nullptr || !CanBackgroundProcesses())
return false;
mach_port_t task_port = port_provider->TaskForPid(Pid());
if (task_port == TASK_NULL)
return false;
if (IsProcessBackgrounded(port_provider) == background)
return true;
task_category_policy category_policy;
category_policy.role =
background ? TASK_BACKGROUND_APPLICATION : TASK_FOREGROUND_APPLICATION;
kern_return_t result =
task_policy_set(task_port, TASK_CATEGORY_POLICY,
reinterpret_cast<task_policy_t>(&category_policy),
TASK_CATEGORY_POLICY_COUNT);
if (result != KERN_SUCCESS) {
MACH_LOG(ERROR, result) << "task_policy_set TASK_CATEGORY_POLICY";
return false;
}
// Latency QoS regulates timer throttling/accuracy. Select default tier
// on foreground because precise timer firing isn't needed.
struct task_qos_policy qos_policy = {
background ? LATENCY_QOS_TIER_5 : LATENCY_QOS_TIER_UNSPECIFIED,
background ? THROUGHPUT_QOS_TIER_5 : THROUGHPUT_QOS_TIER_UNSPECIFIED};
result = task_policy_set(task_port, TASK_OVERRIDE_QOS_POLICY,
reinterpret_cast<task_policy_t>(&qos_policy),
TASK_QOS_POLICY_COUNT);
if (result != KERN_SUCCESS) {
MACH_LOG(ERROR, result) << "task_policy_set TASK_OVERRIDE_QOS_POLICY";
return false;
}
return true;
}
} // namespace base
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