Android6.0 设备Idle状态（三） PowerManagerService
新增的Idle状态感觉在PowerManagerService的代码变动不大，但是其功能其实还有很大的变化，我们先看下持锁这个函数新加的地方。
一、持wakelock的流程
private void acquireWakeLockInternal(IBinder lock, int flags, String tag, String packageName,
WorkSource ws, String historyTag, int uid, int pid) {
synchronized (mLock) {
if (DEBUG_SPEW) {
Slog.d(TAG, "acquireWakeLockInternal: lock=" + Objects.hashCode(lock)
+ ", flags=0x" + Integer.toHexString(flags)
+ ", tag=\"" + tag + "\", ws=" + ws + ", uid=" + uid + ", pid=" + pid);
}
WakeLock wakeLock;
int index = findWakeLockIndexLocked(lock);
boolean notifyAcquire;
if (index >= 0) {
wakeLock = mWakeLocks.get(index);
if (!wakeLock.hasSameProperties(flags, tag, ws, uid, pid)) {
// Update existing wake lock. This shouldn't happen but is harmless.
notifyWakeLockChangingLocked(wakeLock, flags, tag, packageName,
uid, pid, ws, historyTag);
wakeLock.updateProperties(flags, tag, packageName, ws, historyTag, uid, pid);
}
notifyAcquire = false;
} else {
wakeLock = new WakeLock(lock, flags, tag, packageName, ws, historyTag, uid, pid);
try {
lock.linkToDeath(wakeLock, 0);
} catch (RemoteException ex) {
throw new IllegalArgumentException("Wake lock is already dead.");
}
mWakeLocks.add(wakeLock);
setWakeLockDisabledStateLocked(wakeLock);//新增
notifyAcquire = true;
}
applyWakeLockFlagsOnAcquireLocked(wakeLock, uid);
mDirty |= DIRTY_WAKE_LOCKS;
updatePowerStateLocked();
if (notifyAcquire) {
// This needs to be done last so we are sure we have acquired the
// kernel wake lock. Otherwise we have a race where the system may
// go to sleep between the time we start the accounting in battery
// stats and when we actually get around to telling the kernel to
// stay awake.
notifyWakeLockAcquiredLocked(wakeLock);
}
}
}
在新建一个wakelock的时候，会调用setWakeLockDisabledStateLocked这个函数，我们来看下。
private boolean setWakeLockDisabledStateLocked(WakeLock wakeLock) {
if ((wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK)
== PowerManager.PARTIAL_WAKE_LOCK) {
boolean disabled = false;
if (mDeviceIdleMode) {
final int appid = UserHandle.getAppId(wakeLock.mOwnerUid);
// If we are in idle mode, we will ignore all partial wake locks that are
// for application uids that are not whitelisted.
if (appid >= Process.FIRST_APPLICATION_UID &&
Arrays.binarySearch(mDeviceIdleWhitelist, appid) < 0 &&
Arrays.binarySearch(mDeviceIdleTempWhitelist, appid) < 0 &&
mUidState.get(wakeLock.mOwnerUid,
ActivityManager.PROCESS_STATE_CACHED_EMPTY)
> ActivityManager.PROCESS_STATE_FOREGROUND_SERVICE) {
disabled = true;
}
}
if (wakeLock.mDisabled != disabled) {
wakeLock.mDisabled = disabled;
return true;
}
}
return false;
}如果mDeviceIdleMode为true，满足条件判断，wakelock的mDisabled为true
这里PowerManagerService的流程就不讲了，前面分析PowerManagerService的博客都分析过。
再最后调用updateWakeLockSummaryLocked的时候会统计所有的waklock锁
private void updateWakeLockSummaryLocked(int dirty) {
if ((dirty & (DIRTY_WAKE_LOCKS | DIRTY_WAKEFULNESS)) != 0) {
mWakeLockSummary = 0;
final int numWakeLocks = mWakeLocks.size();
for (int i = 0; i < numWakeLocks; i++) {
final WakeLock wakeLock = mWakeLocks.get(i);//遍历所有的wakelock
switch (wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK) {
case PowerManager.PARTIAL_WAKE_LOCK:
if (!wakeLock.mDisabled) {//mDisabled为false，才能持cpu锁
// We only respect this if the wake lock is not disabled.
mWakeLockSummary |= WAKE_LOCK_CPU;
}
break;
case PowerManager.FULL_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_SCREEN_BRIGHT | WAKE_LOCK_BUTTON_BRIGHT;
break;
case PowerManager.SCREEN_BRIGHT_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_SCREEN_BRIGHT;
break;
case PowerManager.SCREEN_DIM_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_SCREEN_DIM;
break;
case PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_PROXIMITY_SCREEN_OFF;
break;
case PowerManager.DOZE_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_DOZE;
break;
case PowerManager.DRAW_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_DRAW;
break;
}
}
// Cancel wake locks that make no sense based on the current state.
if (mWakefulness != WAKEFULNESS_DOZING) {
mWakeLockSummary &= ~(WAKE_LOCK_DOZE | WAKE_LOCK_DRAW);
}
if (mWakefulness == WAKEFULNESS_ASLEEP
|| (mWakeLockSummary & WAKE_LOCK_DOZE) != 0) {
mWakeLockSummary &= ~(WAKE_LOCK_SCREEN_BRIGHT | WAKE_LOCK_SCREEN_DIM
| WAKE_LOCK_BUTTON_BRIGHT);
if (mWakefulness == WAKEFULNESS_ASLEEP) {
mWakeLockSummary &= ~WAKE_LOCK_PROXIMITY_SCREEN_OFF;
}
}
// Infer implied wake locks where necessary based on the current state.
if ((mWakeLockSummary & (WAKE_LOCK_SCREEN_BRIGHT | WAKE_LOCK_SCREEN_DIM)) != 0) {
if (mWakefulness == WAKEFULNESS_AWAKE) {
mWakeLockSummary |= WAKE_LOCK_CPU | WAKE_LOCK_STAY_AWAKE;
} else if (mWakefulness == WAKEFULNESS_DREAMING) {
mWakeLockSummary |= WAKE_LOCK_CPU;
}
}
if ((mWakeLockSummary & WAKE_LOCK_DRAW) != 0) {//这个好像是给WMS绘制用的
mWakeLockSummary |= WAKE_LOCK_CPU;
}
if (DEBUG_SPEW) {
Slog.d(TAG, "updateWakeLockSummaryLocked: mWakefulness="
+ PowerManagerInternal.wakefulnessToString(mWakefulness)
+ ", mWakeLockSummary=0x" + Integer.toHexString(mWakeLockSummary));
}
}
}
这样的话当系统处于idle状态，而且不是在白名单里的应用持的cpu锁是无效的。
二、设置Idle状态接口
我们再来看下PowerManagerService中的设置设备Idle的接口：
@Override
public void setDeviceIdleMode(boolean enabled) {
setDeviceIdleModeInternal(enabled);
}这个接口是LocalService的，所以只能在SystemServer中的service调用。
再看下setDeviceIdleModeInternal函数：
void setDeviceIdleModeInternal(boolean enabled) {
synchronized (mLock) {
if (mDeviceIdleMode != enabled) {
mDeviceIdleMode = enabled;//设置状态
updateWakeLockDisabledStatesLocked();//更新wakelock
if (enabled) {
EventLogTags.writeDeviceIdleOnPhase("power");
} else {
EventLogTags.writeDeviceIdleOffPhase("power");
}
}
}
}然后就是遍历每个wakelock，重新去设置其mDisabled。
private void updateWakeLockDisabledStatesLocked() {
boolean changed = false;
final int numWakeLocks = mWakeLocks.size();
for (int i = 0; i < numWakeLocks; i++) {
final WakeLock wakeLock = mWakeLocks.get(i);
if ((wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK)
== PowerManager.PARTIAL_WAKE_LOCK) {
if (setWakeLockDisabledStateLocked(wakeLock)) {//重新设置mDisabled
changed = true;
if (wakeLock.mDisabled) {
// This wake lock is no longer being respected.
notifyWakeLockReleasedLocked(wakeLock);//通知更新
} else {
notifyWakeLockAcquiredLocked(wakeLock);
}
}
}
}
if (changed) {
mDirty |= DIRTY_WAKE_LOCKS;
updatePowerStateLocked();
}
}
private boolean setWakeLockDisabledStateLocked(WakeLock wakeLock) {
if ((wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK)
== PowerManager.PARTIAL_WAKE_LOCK) {
boolean disabled = false;
if (mDeviceIdleMode) {
final int appid = UserHandle.getAppId(wakeLock.mOwnerUid);
// If we are in idle mode, we will ignore all partial wake locks that are
// for application uids that are not whitelisted.
if (appid >= Process.FIRST_APPLICATION_UID &&
Arrays.binarySearch(mDeviceIdleWhitelist, appid) < 0 &&
Arrays.binarySearch(mDeviceIdleTempWhitelist, appid) < 0 &&
mUidState.get(wakeLock.mOwnerUid,
ActivityManager.PROCESS_STATE_CACHED_EMPTY)
> ActivityManager.PROCESS_STATE_FOREGROUND_SERVICE) {
disabled = true;
}
}
if (wakeLock.mDisabled != disabled) {
wakeLock.mDisabled = disabled;
return true;
}
}
return false;
}
三、设置白名单
设置白名单的接口
@Override
public void setDeviceIdleWhitelist(int[] appids) {
setDeviceIdleWhitelistInternal(appids);
}setDeviceIdleWhitelistInternal函数也是调用了updateWakeLockDisabledStatesLocked函数
void setDeviceIdleWhitelistInternal(int[] appids) {
synchronized (mLock) {
mDeviceIdleWhitelist = appids;
if (mDeviceIdleMode) {
updateWakeLockDisabledStatesLocked();
}
}
}
updateWakeLockDisabledStatesLocked和之前一样，最后我们再主要分析下setWakeLockDisabledStateLocked函数
private boolean setWakeLockDisabledStateLocked(WakeLock wakeLock) {
if ((wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK)
== PowerManager.PARTIAL_WAKE_LOCK) {
boolean disabled = false;
if (mDeviceIdleMode) {
final int appid = UserHandle.getAppId(wakeLock.mOwnerUid);
// If we are in idle mode, we will ignore all partial wake locks that are
// for application uids that are not whitelisted.
if (appid >= Process.FIRST_APPLICATION_UID &&//是应用
Arrays.binarySearch(mDeviceIdleWhitelist, appid) < 0 &&//白名单都没有
Arrays.binarySearch(mDeviceIdleTempWhitelist, appid) < 0 &&//临时白名单中也没有
mUidState.get(wakeLock.mOwnerUid,
ActivityManager.PROCESS_STATE_CACHED_EMPTY)
> ActivityManager.PROCESS_STATE_FOREGROUND_SERVICE) {
disabled = true;//所有条件都满足
}
}
if (wakeLock.mDisabled != disabled) {
wakeLock.mDisabled = disabled;
return true;
}
}
return false;
}上面所有条件都满足disabled为true。