mt6735 如何避免后台音乐被low memory结束生命

[DESCRIPTION]
如何避免后台音乐被low memory结束生命
[SOLUTION]
为防止某些进程被 low memory 意外杀掉，可以将其加入白名单，降低误伤的概率；
一般来说， low memory killer 会首先选择 adj value 徘徊在 9 ～ 15 的 process 去结束生命；
1. 在 ActivityManagerService.Java 增加如下代码：
static final String[] mThirdPartyAppWhiteList = { "android.process.media
"};
static final int [] mThirdPartyAppAdj = {7};

2.在ActivityManagerService.java修改如下代码：
private final boolean updateOomAdjLocked(ProcessRecord app, int hiddenAdj,
int CLIentHiddenAdj, int emptyAdj, ProcessRecord TOP_APP, boolean
doingAll) {
app.hiddenAdj = hiddenAdj;
app.clientHiddenAdj = clientHiddenAdj;
app.emptyAdj = emptyAdj;
if (app.thread == null) {
return false;
}
final boolean wasKeeping = app.keeping;
boolean success = true;
boolean isWLProc = false; /// M: ALPS00497111 [Volunteer free] LCA Memory
Optimized
boolean isThirdPartyAppWhiteProcess = false; //add
int mThirdPartyAdj = ProcessList.HIDDEN_APP_MIN_ADJ;
computeOomAdjLocked(app, hiddenAdj, clientHiddenAdj, emptyAdj, TOP_APP,
false, doingAll);
if (app.curRawAdj ！= app.setRawAdj) {
if (wasKeeping && ！app.keeping) {
// This app is no longer something we want to keep. Note
// its current wake lock time to later know to kill it if
// it is not behaving well.
BatteryStatSIMpl stats = mBatteryStatsService.getActiveStatistics();
synchronized (stats) {
app.lastWakeTime = stats.getProcessWakeTime(app.info.uid,
app.pid, SystemClock.elapsedRealtime());
}
app.lastCpuTime = app.curCpuTime;
}
app.setRawAdj = app.curRawAdj;
}
if (app.curAdj ！= app.setAdj) {
/// M: LTK @{
if (FeatureOption.mtk_MEMORY_COMPRESSION_SUPPORT) {
if(app.curAdj > app.setAdj && (app.curAdj >= ProcessList.PREVIOUS_APP_ADJ)
&& app.hasShownUi) {
try {
IAmsPlus amsplus = MediatekClassFactory.createInstance(IAmsPlus.class);
amsplus.afterAdjAdjustment(mMainStack.convertProcessRecord(app),
app.setAdj,
app.curAdj,
mMainStack.convertLaunchRecord(mMainStack.topRunningActivityLocked(null)))
;
} catch (Exception e) {
Log.w(TAG, "[LTK] Exception thrown during afterAdjAdjustment failed:", e);
}
}
}
/// @}
/// M: ALPS00497111 [Volunteer free] LCA Memory Optimized @{
if(FeatureOption.MTK_LCA_RAM_OPTIMIZE)
{
for(int num = 0; num <= WL_PROCNAME.length -1 ;num++)
{
if(WL_PROCNAME[num].equals(app.processName) &&
app.curAdj > ProcessList.HIDDEN_APP_MIN_ADJ)
{
isWLProc = true;
break;
}
}
}
//add 如下的 code
if(FeatureOption.MTK_LCA_RAM_OPTIMIZE)
{
if (mThirdPartyAppWhiteList.length ！= mThirdPartyAppAdj.length)
{
throw new Exception("mThirdPartyAppWhiteList is not match
mThirdPartyAppAdj");
}
for(int num = 0; num <= mThirdPartyAppWhiteList.length -1 ;num++)
{
if(mThirdPartyAppWhiteList[num].equals(app.processName) &&
app.curAdj > mThirdPartyAppAdj[num])
{
isThirdPartyAppWhiteProcess = true;
mThirdPartyAdj = mThirdPartyAppAdj[num];
}
}
}
//add code end
if(isWLProc)
{
if (Process.setOomAdj(app.pid, ProcessList.HIDDEN_APP_MIN_ADJ)) {
if (DEBUG_SWITCH || DEBUG_OOM_ADJ) Slog.v(
TAG, "Set " + app.pid + " " + app.processName +
" adj " + ProcessList.HIDDEN_APP_MIN_ADJ + ": " + app.adjType);
app.setAdj = ProcessList.HIDDEN_APP_MIN_ADJ;
} else {
success = false;
Slog.w(TAG, "Failed setting oom adj of " + app + " to " +
ProcessList.HIDDEN_APP_MIN_ADJ);
}
}
// 添加如下的判断：
else if(isThirdPartyAppWhiteProcess)
{
if (Process.setOomAdj(app.pid, mThirdPartyAdj)) {
if (DEBUG_SWITCH || DEBUG_OOM_ADJ) Slog.v(
TAG, "Set " + app.pid + " " + app.processName +
" adj " + mThirdPartyAdj + ": " + app.adjType);
app.setAdj = mThirdPartyAdj;
} else {
success = false;
Slog.w(TAG, "Failed setting oom adj of " + app + " to " + mThirdPartyAdj);
}
}
else
{
if (Process.setOomAdj(app.pid, app.curAdj)) {
if (DEBUG_SWITCH || DEBUG_OOM_ADJ) Slog.v(
TAG, "Set " + app.pid + " " + app.processName +
" adj " + app.curAdj + ": " + app.adjType);
app.setAdj = app.curAdj;
} else {
success = false;
Slog.w(TAG, "Failed setting oom adj of " + app + " to " + app.curAdj);
}
}
/// @}
}
if (app.setSchedGroup ！= app.curSchedGroup) {
app.setSchedGroup = app.curSchedGroup;
if (DEBUG_SWITCH || DEBUG_OOM_ADJ) Slog.v(TAG,
"Setting process group of " + app.processName
+ " to " + app.curSchedGroup);
if (app.waitingToKill ！= null &&
app.setSchedGroup == Process.THREAD_GROUP_BG_NONINTERACTIVE) {
Slog.i(TAG, "Killing " + app.toShortString() + ": " + app.waitingToKill);
EventLog.writeEvent(EventLogTags.AM_KILL, app.userId, app.pid,
app.processName, app.setAdj, app.waitingToKill);
app.killedBackground = true;
Process.killProcessQuiet(app.pid);
success = false;
} else {
if (true) {
long oldId = Binder.clearCallingIdentity();
try {
Process.setProcessGroup(app.pid, app.curSchedGroup);
} catch (Exception e) {
Slog.w(TAG, "Failed setting process group of " + app.pid
+ " to " + app.curSchedGroup);
e.printStackTrace();
} finally {
Binder.restoreCallingIdentity(oldId);
}
} else {
if (app.thread ！= null) {
try {
app.thread.setSchedulingGroup(app.curSchedGroup);
} catch (RemoteException e) {
}
}
}
}
}
return success;
}