1.1 computeOomAdjLocked计算Adj概览图
computeOomAdjLocked
2.1 computeOomAdjLocked 计算进程Adj分析
final ActivityRecord TOP_ACT = resumedAppLocked(); // 2.2
final ProcessRecord TOP_APP = TOP_ACT != null ? TOP_ACT.app : null;
private final int computeOomAdjLocked(ProcessRecord app, int cachedAdj, ProcessRecord TOP_APP,
boolean doingAll, long now) {
if (mAdjSeq == app.adjSeq) {
// This adjustment has already been computed.
return app.curRawAdj;
}
if (app.thread == null) {
app.adjSeq = mAdjSeq;
app.curSchedGroup = ProcessList.SCHED_GROUP_BACKGROUND;
app.curProcState = ActivityManager.PROCESS_STATE_CACHED_EMPTY;
return (app.curAdj=app.curRawAdj=ProcessList.CACHED_APP_MAX_ADJ);
}
app.adjTypeCode = ActivityManager.RunningAppProcessInfo.REASON_UNKNOWN;
app.adjSource = null;
app.adjTarget = null;
app.empty = false;
app.cached = false;
final int activitiesSize = app.activities.size();
// the process running the current foreground app adj 比前台进程高
if (app.maxAdj <= ProcessList.FOREGROUND_APP_ADJ) {
// The max adjustment doesn't allow this app to be anything
// below foreground, so it is not worth doing work for it.
app.adjType = "fixed";
app.adjSeq = mAdjSeq;
app.curRawAdj = app.maxAdj;
app.foregroundActivities = false;
app.curSchedGroup = ProcessList.SCHED_GROUP_DEFAULT;
app.curProcState = ActivityManager.PROCESS_STATE_PERSISTENT;
// System processes can do UI, and when they do we want to have
// them trim their memory after the user leaves the UI. To
// facilitate this, here we need to determine whether or not it
// is currently showing UI.
app.systemNoUi = true;
if (app == TOP_APP) {
app.systemNoUi = false;
app.curSchedGroup = ProcessList.SCHED_GROUP_TOP_APP;
app.adjType = "pers-top-activity";
} else if (app.hasTopUi) {
app.systemNoUi = false;
app.curSchedGroup = ProcessList.SCHED_GROUP_TOP_APP;
app.adjType = "pers-top-ui";
} else if (activitiesSize > 0) {
for (int j = 0; j < activitiesSize; j++) {
final ActivityRecord r = app.activities.get(j);
if (r.visible) {
app.systemNoUi = false;
}
}
}
if (!app.systemNoUi) {// 存在Ui的情况
// Process is a persistent system process and is doing UI
app.curProcState = ActivityManager.PROCESS_STATE_PERSISTENT_UI;
}
return (app.curAdj=app.maxAdj);
}
app.systemNoUi = false;
final int PROCESS_STATE_CUR_TOP = mTopProcessState;
// 前台进程top app（launcher）, instrumentationClass 正在执行的广播 service
// Determine the importance of the process, starting with most
// important to least, and assign an appropriate OOM adjustment.
int adj;
int schedGroup;
int procState;
boolean foregroundActivities = false;
BroadcastQueue queue;
if (app == TOP_APP) {
// The last app on the list is the foreground app.
adj = ProcessList.FOREGROUND_APP_ADJ;
schedGroup = ProcessList.SCHED_GROUP_TOP_APP;
app.adjType = "top-activity";
foregroundActivities = true;
procState = PROCESS_STATE_CUR_TOP;
if(app == mHomeProcess) {
mHomeKilled = false;
mHomeProcessName = mHomeProcess.processName;
}
} else if (app.instrumentationClass != null) {
// Don't want to kill running instrumentation.
adj = ProcessList.FOREGROUND_APP_ADJ;
schedGroup = ProcessList.SCHED_GROUP_DEFAULT;
app.adjType = "instrumentation";
procState = ActivityManager.PROCESS_STATE_FOREGROUND_SERVICE;
} else if ((queue = isReceivingBroadcast(app)) != null) {
// An app that is currently receiving a broadcast also
// counts as being in the foreground for OOM killer purposes.
// It's placed in a sched group based on the nature of the
// broadcast as reflected by which queue it's active in.
adj = ProcessList.FOREGROUND_APP_ADJ;
schedGroup = (queue == mFgBroadcastQueue)
? ProcessList.SCHED_GROUP_DEFAULT : ProcessList.SCHED_GROUP_BACKGROUND;
app.adjType = "broadcast";
procState = ActivityManager.PROCESS_STATE_RECEIVER;
} else if (app.executingServices.size() > 0) {
// An app that is currently executing a service callback also
// counts as being in the foreground.
adj = ProcessList.FOREGROUND_APP_ADJ;
schedGroup = app.execServicesFg ?
ProcessList.SCHED_GROUP_DEFAULT : ProcessList.SCHED_GROUP_BACKGROUND;
app.adjType = "exec-service";
procState = ActivityManager.PROCESS_STATE_SERVICE;
//Slog.i(TAG, "EXEC " + (app.execServicesFg ? "FG" : "BG") + ": " + app);
} else {
// As far as we know the process is empty. We may change our mind later.
schedGroup = ProcessList.SCHED_GROUP_BACKGROUND;
// At this point we don't actually know the adjustment. Use the cached adj
// value that the caller wants us to.
adj = cachedAdj;
procState = ActivityManager.PROCESS_STATE_CACHED_EMPTY;
app.cached = true;
app.empty = true;
app.adjType = "cch-empty";
if (mHomeKilled && app.processName.equals(mHomeProcessName)) {
adj = ProcessList.PERSISTENT_PROC_ADJ;
schedGroup = Process.THREAD_GROUP_DEFAULT;
app.cached = false;
app.empty = false;
app.adjType = "top-activity";
}
}
// Examine all activities if not already foreground. 非前台Activity
if (!foregroundActivities && activitiesSize > 0) {
int minLayer = ProcessList.VISIBLE_APP_LAYER_MAX;
for (int j = 0; j < activitiesSize; j++) {
final ActivityRecord r = app.activities.get(j);
if (r.app != app) {
Log.e(TAG, "Found activity " + r + " in proc activity list using " + r.app
+ " instead of expected " + app);
if (r.app == null || (r.app.uid == app.uid)) {
// Only fix things up when they look sane
r.app = app;
} else {
continue;
}
}
if (r.visible) { // Activity可见
// App has a visible activity; only upgrade adjustment.
if (adj > ProcessList.VISIBLE_APP_ADJ) {
adj = ProcessList.VISIBLE_APP_ADJ;
app.adjType = "visible";
}
if (procState > PROCESS_STATE_CUR_TOP) {
procState = PROCESS_STATE_CUR_TOP;
}
schedGroup = ProcessList.SCHED_GROUP_DEFAULT;
app.cached = false;
app.empty = false;
foregroundActivities = true;
if (r.task != null && minLayer > 0) {
final int layer = r.task.mLayerRank;
if (layer >= 0 && minLayer > layer) {
minLayer = layer;
}
}
break;
} else if (r.state == ActivityState.PAUSING || r.state == ActivityState.PAUSED) { // 处于暂停或已经暂停
if (adj > ProcessList.PERCEPTIBLE_APP_ADJ) {
adj = ProcessList.PERCEPTIBLE_APP_ADJ;
app.adjType = "pausing";
}
if (procState > PROCESS_STATE_CUR_TOP) {
procState = PROCESS_STATE_CUR_TOP;
}
schedGroup = ProcessList.SCHED_GROUP_DEFAULT;
app.cached = false;
app.empty = false;
foregroundActivities = true;
} else if (r.state == ActivityState.STOPPING) {
if (adj > ProcessList.PERCEPTIBLE_APP_ADJ) {
adj = ProcessList.PERCEPTIBLE_APP_ADJ;
app.adjType = "stopping";
}
// For the process state, we will at this point consider the
// process to be cached. It will be cached either as an activity
// or empty depending on whether the activity is finishing. We do
// this so that we can treat the process as cached for purposes of
// memory trimming (determing current memory level, trim command to
// send to process) since there can be an arbitrary number of stopping
// processes and they should soon all go into the cached state.
if (!r.finishing) {
if (procState > ActivityManager.PROCESS_STATE_LAST_ACTIVITY) {
procState = ActivityManager.PROCESS_STATE_LAST_ACTIVITY;
}
}
app.cached = false;
app.empty = false;
foregroundActivities = true;
} else {
if (procState > ActivityManager.PROCESS_STATE_CACHED_ACTIVITY) {
procState = ActivityManager.PROCESS_STATE_CACHED_ACTIVITY;
app.adjType = "cch-act";
}
}
}
if (adj == ProcessList.VISIBLE_APP_ADJ) {
adj += minLayer;
}
}
if (adj > ProcessList.PERCEPTIBLE_APP_ADJ
|| procState > ActivityManager.PROCESS_STATE_FOREGROUND_SERVICE) {
if (app.foregroundServices) { // 前台service
// The user is aware of this app, so make it visible.
adj = ProcessList.PERCEPTIBLE_APP_ADJ;
procState = ActivityManager.PROCESS_STATE_FOREGROUND_SERVICE;
app.cached = false;
app.adjType = "fg-service";
schedGroup = ProcessList.SCHED_GROUP_DEFAULT;
} else if (app.forcingToForeground != null) {//
// The user is aware of this app, so make it visible.
adj = ProcessList.PERCEPTIBLE_APP_ADJ;
procState = ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND;
app.cached = false;
app.adjType = "force-fg";
app.adjSource = app.forcingToForeground;
schedGroup = ProcessList.SCHED_GROUP_DEFAULT;
}
}
if (app == mHeavyWeightProcess) { // 解析init.rc启动的进程 AudioFlinger等
if (adj > ProcessList.HEAVY_WEIGHT_APP_ADJ) {
// We don't want to kill the current heavy-weight process.
adj = ProcessList.HEAVY_WEIGHT_APP_ADJ;
schedGroup = ProcessList.SCHED_GROUP_BACKGROUND;
app.cached = false;
app.adjType = "heavy";
}
if (procState > ActivityManager.PROCESS_STATE_HEAVY_WEIGHT) {
procState = ActivityManager.PROCESS_STATE_HEAVY_WEIGHT;
}
}
if (app == mHomeProcess) {
// This is the process holding the activity the user last visited that is in a different process from the one they are currently in.
if (adj > ProcessList.HOME_APP_ADJ) {
// This process is hosting what we currently consider to be the
// home app, so we don't want to let it go into the background.
adj = ProcessList.HOME_APP_ADJ;
schedGroup = ProcessList.SCHED_GROUP_BACKGROUND;
app.cached = false;
app.adjType = "home";
}
if (procState > ActivityManager.PROCESS_STATE_HOME) {
procState = ActivityManager.PROCESS_STATE_HOME;
}
}
// The time at which the previous process was last visible 前一个可见
if (app == mPreviousProcess && app.activities.size() > 0) {
if (adj > ProcessList.PREVIOUS_APP_ADJ) { // qian
// This was the previous process that showed UI to the user.
// We want to try to keep it around more aggressively, to give
// a good experience around switching between two apps.
adj = ProcessList.PREVIOUS_APP_ADJ;
schedGroup = ProcessList.SCHED_GROUP_BACKGROUND;
app.cached = false;
app.adjType = "previous";
}
if (procState > ActivityManager.PROCESS_STATE_LAST_ACTIVITY) {
procState = ActivityManager.PROCESS_STATE_LAST_ACTIVITY;
}
}
// By default, we use the computed adjustment. It may be changed if
// there are applications dependent on our services or providers, but
// this gives us a baseline and makes sure we don't get into an
// infinite recursion.
app.adjSeq = mAdjSeq;
app.curRawAdj = adj;
app.hasStartedServices = false;
//备份进程
if (mBackupTarget != null && app == mBackupTarget.app) {
// If possible we want to avoid killing apps while they're being backed up
if (adj > ProcessList.BACKUP_APP_ADJ) {
if (DEBUG_BACKUP) Slog.v(TAG_BACKUP, "oom BACKUP_APP_ADJ for " + app);
adj = ProcessList.BACKUP_APP_ADJ;
if (procState > ActivityManager.PROCESS_STATE_IMPORTANT_BACKGROUND) {
procState = ActivityManager.PROCESS_STATE_IMPORTANT_BACKGROUND;
}
app.adjType = "backup";
app.cached = false;
}
if (procState > ActivityManager.PROCESS_STATE_BACKUP) {
procState = ActivityManager.PROCESS_STATE_BACKUP;
}
}
...
// service contentprovider相关的adj计算
}
2.2 ActivityStackSupervisor::resumedAppLocked 获取Top_app
ActivityRecord resumedAppLocked() {
ActivityStack stack = mFocusedStack; // 焦点ActivityStack
if (stack == null) {
return null;
}
ActivityRecord resumedActivity = stack.mResumedActivity; // 当前正在运行的Activity
if (resumedActivity == null || resumedActivity.app == null) {
resumedActivity = stack.mPausingActivity;// 当前正在暂停的Activity
if (resumedActivity == null || resumedActivity.app == null) {
resumedActivity = stack.topRunningActivityLocked(); // 遍历ArrayList<TaskRecord>查询
}
}
return resumedActivity;
}
