// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chromeos/ash/components/memory/mglru.h"
#include "base/feature_list.h"
#include "base/files/file_util.h"
#include "base/functional/bind.h"
#include "base/metrics/field_trial_params.h"
#include "base/strings/string_number_conversions.h"
#include "base/system/sys_info.h"
#include "chromeos/ash/components/dbus/swap_management/swap_management_client.h"
namespace ash {
namespace {
constexpr char kMGLRUEnableFile[] = "/sys/kernel/mm/lru_gen/enabled";
// KernelSupportsMGLRU will check if the kernel supports mg lru, this is as
// easy as looking for the presences of the enable file.
bool KernelSupportsMGLRU() {
static const bool supported_mglru =
base::PathExists(base::FilePath(kMGLRUEnableFile));
return supported_mglru;
}
void OnMGLRUSetEnable(bool success) {
if (!success) {
LOG(ERROR) << "Unable to configure MGLRU.";
return;
}
VLOG(1) << "swap_management configured MGLRU with value: "
<< kMGLRUEnableValue.Get();
}
} // namespace
BASE_FEATURE(kMGLRUEnable, "MGLRUEnable", base::FEATURE_DISABLED_BY_DEFAULT);
const base::FeatureParam<int> kMGLRUEnableValue = {&kMGLRUEnable,
"MGLRUEnableValue", 0};
// InitializeMGLRU will attempt to configure MGLRU with the experimental
// parameters for this user.
void InitializeMGLRU() {
bool feature_enabled = base::FeatureList::IsEnabled(kMGLRUEnable);
if (!feature_enabled) {
VLOG(1) << "MGLRU feature is disabled";
return;
}
if (!KernelSupportsMGLRU()) {
// Only log an error when we're running on REAL CrOS without kernel
// support.
LOG_IF(ERROR, base::SysInfo::IsRunningOnChromeOS())
<< "Unable to configure MGLRU: no kernel support";
return;
}
int feature_value = kMGLRUEnableValue.Get();
if (feature_value < 0 ||
feature_value > std::numeric_limits<uint8_t>::max()) {
LOG(ERROR) << "Invalid value set for feature value.";
return;
}
SwapManagementClient* swap_management_client = SwapManagementClient::Get();
CHECK(swap_management_client);
swap_management_client->MGLRUSetEnable(static_cast<uint8_t>(feature_value),
base::BindOnce(&OnMGLRUSetEnable));
}
} // namespace ash