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Lowmemorykiller笔记

来源：互联网发布：中国工控网软件下载编辑：程序博客网时间：2024/05/16 22:29

从zygote孵化出来的进程都会记录在ActivityManagerService.mLruProcesses列表中，由ActivityManagerService进行统一管理，ActivityManagerService核心业务之一便是时时更新进程的状态，根据状态计算出进程对应的OomAdj值，这个值会传递到kernel中去，kernel有个低内存回收机制，在内存达到一定阀值时会触发清理OomAdj值高的进程，这边是Lowmemorykiller工作原理。

第一部分：进程OomAdj值的设置

这个流程中，ActivityManagerService会计算出进程的OomAdj值，然后通过Lmkd这个native进程来将OomAdj值分别写入对应进程的oom_score_adj节点去。可以通过cat /proc/%pid/oom_score_adj来查看每个进程的OomAdj值。

注意：

①OomAdj值越小表示优先级越高，越不容易被kill。

②ActivityManagerService中为进程设定的OomAdj值取值范围为-16~16，设定到oom_score_adj节点中的值是经过 OomAdj*1000/17 公式计算出来的。

③native进程OomAdj值默认为-17，也就是说native进程oom_score_adj节点中值必是-1000.

第二部分：核心调用lowmem_shrink()

这个函数主要根据当前剩余内存与lowmem_minfree来评判当前内存已经达到哪个阀值以下(每个阀值都对应一个lowmem_adj值)，进而得出一个lowmem_adj基准值（只有OomAdj值大于这个lowmem_adj基准值的进程才可能被杀）。

代码在/drivers/staging/android/lowmemorykiller.c

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static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc)
{
struct task_struct *tsk;
struct task_struct *selected = NULL;
int rem = 0;
int tasksize;
int i;
int min_score_adj = OOM_SCORE_ADJ_MAX + 1;
int selected_tasksize = 0;
int selected_oom_score_adj;
int array_size = ARRAY_SIZE(lowmem_adj);
int other_free = global_page_state(NR_FREE_PAGES) - totalreserve_pages;
int other_file = global_page_state(NR_FILE_PAGES) -
global_page_state(NR_SHMEM);
if (lowmem_adj_size < array_size)
array_size = lowmem_adj_size;
if (lowmem_minfree_size < array_size)
array_size = lowmem_minfree_size;
for (i = 0; i < array_size; i++) { //根据当前内存与lowmem_minfree数组进行评判，找到lowmem_adj基准值赋给min_score_adj；
if (other_free < lowmem_minfree[i] &&
other_file < lowmem_minfree[i]) {
min_score_adj = lowmem_adj[i];
break;
}
}
if (sc->nr_to_scan > 0)
lowmem_print(3, "lowmem_shrink %lu, %x, ofree %d %d, ma %d\n",
sc->nr_to_scan, sc->gfp_mask, other_free,
other_file, min_score_adj);
rem = global_page_state(NR_ACTIVE_ANON) +
global_page_state(NR_ACTIVE_FILE) +
global_page_state(NR_INACTIVE_ANON) +
global_page_state(NR_INACTIVE_FILE);
if (sc->nr_to_scan <= 0 || min_score_adj == OOM_SCORE_ADJ_MAX + 1) {
lowmem_print(5, "lowmem_shrink %lu, %x, return %d\n",
sc->nr_to_scan, sc->gfp_mask, rem);
return rem;
}
selected_oom_score_adj = min_score_adj;
rcu_read_lock();
for_each_process(tsk) { //该for循环找出oom_score_adj值最大的进程作为目标进程(将被kill)，如果最大oom_score_adj值有多个进程，那么选取rss值最大的进程为目标进程；
struct task_struct *p;
int oom_score_adj;
if (tsk->flags & PF_KTHREAD)
continue;
p = find_lock_task_mm(tsk);
if (!p)
continue;
if (test_tsk_thread_flag(p, TIF_MEMDIE) &&
time_before_eq(jiffies, lowmem_deathpending_timeout)) {
task_unlock(p);
rcu_read_unlock();
return 0;
}
oom_score_adj = p->signal->oom_score_adj;
if (oom_score_adj < min_score_adj) {
task_unlock(p);
continue;
}
tasksize = get_mm_rss(p->mm);
task_unlock(p);
if (tasksize <= 0)
continue;
if (selected) {
if (oom_score_adj < selected_oom_score_adj)
continue;
if (oom_score_adj == selected_oom_score_adj &&
tasksize <= selected_tasksize)
continue;
}
selected = p;
selected_tasksize = tasksize;
selected_oom_score_adj = oom_score_adj;
lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
p->pid, p->comm, oom_score_adj, tasksize);
}
if (selected) { //前面for循环找到一个目标进程，那么便调用send_sig()干掉它。
lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
selected->pid, selected->comm,
selected_oom_score_adj, selected_tasksize);
lowmem_deathpending_timeout = jiffies + HZ;
send_sig(SIGKILL, selected, 0);
set_tsk_thread_flag(selected, TIF_MEMDIE);
rem -= selected_tasksize;
}
lowmem_print(4, "lowmem_shrink %lu, %x, return %d\n",
sc->nr_to_scan, sc->gfp_mask, rem);
rcu_read_unlock();
return rem;
}

该函数的逻辑很简单，就是kill掉Oomadj值大的进程来回收内存。

注意：由于native进程的Oomadj值为-17，SystemServer进程的Oomadj值为-16，毫无疑问native进程不会被Lowmemorykiller干掉。

第三部分：Oomadj的计算

OomAdj的计算主要在computeOomAdjLocked()函数中完成。

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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 = Process.THREAD_GROUP_BG_NONINTERACTIVE;
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();
if (app.maxAdj <= ProcessList.FOREGROUND_APP_ADJ) { //如果是常驻进程、SystemServer进程，那么该条件是满足的，对于一般进程maxAdj值为UNKNOWN_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 = Process.THREAD_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;
} 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) { //如果进程是当前resume activity的进程，或者有可见的activity，那么把curProcState修改成PROCESS_STATE_PERSISTENT_UI
app.curProcState = ActivityManager.PROCESS_STATE_PERSISTENT_UI;
}
return (app.curAdj=app.maxAdj);
}
app.systemNoUi = false; /*以下逻辑是计算普通进程的Oomadj值，主要计算进程的adj、schedGroup、procState、foregroundActivities四个变量*/
// 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) { //这大段if else逻辑里面的条件是权重最高的，如果满足这些条件之一，那么几个状态值基本就确定下来了，如果都不满足，那么最后一个else会给一个初值；
// The last app on the list is the foreground app.
adj = ProcessList.FOREGROUND_APP_ADJ;
schedGroup = Process.THREAD_GROUP_DEFAULT;
app.adjType = "top-activity";
foregroundActivities = true;
procState = ActivityManager.PROCESS_STATE_TOP;
} else if (app.instrumentationClass != null) {
// Don't want to kill running instrumentation.
adj = ProcessList.FOREGROUND_APP_ADJ;
schedGroup = Process.THREAD_GROUP_DEFAULT;
app.adjType = "instrumentation";
procState = ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND;
} 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)
? Process.THREAD_GROUP_DEFAULT : Process.THREAD_GROUP_BG_NONINTERACTIVE;
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 ?
Process.THREAD_GROUP_DEFAULT : Process.THREAD_GROUP_BG_NONINTERACTIVE;
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 = Process.THREAD_GROUP_BG_NONINTERACTIVE;
// At this point we don't actually know the adjustment. Use the cached adj
// value that the caller wants us to.
adj = cachedAdj; //cachedAdj值为进程的上一次计算出来的Oomadj值或UNKNOWN_ADJ，我们把它假设成UNKNOWN_ADJ好了。
procState = ActivityManager.PROCESS_STATE_CACHED_EMPTY;
app.cached = true;
app.empty = true;
app.adjType = "cch-empty";
}
// Examine all activities if not already foreground.
if (!foregroundActivities && activitiesSize > 0) { //这段逻辑主要遍历进程中的所有activity，根据这些activity的状态来更新adj、procState等值；
for (int j = 0; j < activitiesSize; j++) {
final ActivityRecord r = app.activities.get(j);
if (r.app != app) {
Slog.w(TAG, "Wtf, activity " + r + " in proc activity list not using proc "
+ app + "?!?");
continue;
}
if (r.visible) {
// App has a visible activity; only upgrade adjustment.
if (adj > ProcessList.VISIBLE_APP_ADJ) {
adj = ProcessList.VISIBLE_APP_ADJ;
app.adjType = "visible";
}
if (procState > ActivityManager.PROCESS_STATE_TOP) {
procState = ActivityManager.PROCESS_STATE_TOP;
}
schedGroup = Process.THREAD_GROUP_DEFAULT;
app.cached = false;
app.empty = false;
foregroundActivities = true;
break;
} else if (r.state == ActivityState.PAUSING || r.state == ActivityState.PAUSED) {
if (adj > ProcessList.PERCEPTIBLE_APP_ADJ) {
adj = ProcessList.PERCEPTIBLE_APP_ADJ;
app.adjType = "pausing";
}
if (procState > ActivityManager.PROCESS_STATE_TOP) {
procState = ActivityManager.PROCESS_STATE_TOP;
}
schedGroup = Process.THREAD_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.PERCEPTIBLE_APP_ADJ) { //根据进程是否有前台后台service来更新adj、procState等值，当然如果以前算出来的adj＜=PERCEPTIBLE_APP_ADJ，那就没必要考虑前台后台service了；
if (app.foregroundServices) {
// 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 = "fg-service";
schedGroup = Process.THREAD_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 = Process.THREAD_GROUP_DEFAULT;
}
}
if (app == mHeavyWeightProcess) { //判断进程是否mHeavyWeightProcess进程
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 = Process.THREAD_GROUP_BG_NONINTERACTIVE;
app.cached = false;
app.adjType = "heavy";
}
if (procState > ActivityManager.PROCESS_STATE_HEAVY_WEIGHT) {
procState = ActivityManager.PROCESS_STATE_HEAVY_WEIGHT;
}
}
if (app == mHomeProcess) { //判断是否launcher进程；
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 = Process.THREAD_GROUP_BG_NONINTERACTIVE;
app.cached = false;
app.adjType = "home";
}
if (procState > ActivityManager.PROCESS_STATE_HOME) {
procState = ActivityManager.PROCESS_STATE_HOME;
}
}
if (app == mPreviousProcess && app.activities.size() > 0) {<span style="white-space:pre"> </span>//mPreviousProcess代表last Stoped activity所在的进程
if (adj > ProcessList.PREVIOUS_APP_ADJ) {
// 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 = Process.THREAD_GROUP_BG_NONINTERACTIVE;
app.cached = false;
app.adjType = "previous";
}
if (procState > ActivityManager.PROCESS_STATE_LAST_ACTIVITY) {
procState = ActivityManager.PROCESS_STATE_LAST_ACTIVITY;
}
}
<span style="white-space:pre"> </span>/*至此已经初步设置了Oomadj值，下面的逻辑就是根据service、provider来微调<span style="font-family: Arial, Helvetica, sans-serif;">Oomadj值</span>*/
if (false) Slog.i(TAG, "OOM " + app + ": initial adj=" + adj
+ " reason=" + app.adjType);
// 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;
if (mBackupTarget != null && app == mBackupTarget.app) {<span style="white-space:pre"> </span>//判断进程是否正在备份
// 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, "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;
}
}

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boolean mayBeTop = false;
for (int is = app.services.size()-1;
is >= 0 && (adj > ProcessList.FOREGROUND_APP_ADJ
|| schedGroup == Process.THREAD_GROUP_BG_NONINTERACTIVE
|| procState > ActivityManager.PROCESS_STATE_TOP);
is--) {
ServiceRecord s = app.services.valueAt(is);
if (s.startRequested) {<span style="white-space:pre"> </span>//<span style="font-family: Arial, Helvetica, sans-serif;">startRequested=true表示service已经启动了，没有被stop；</span>
app.hasStartedServices = true;
if (procState > ActivityManager.PROCESS_STATE_SERVICE) {
procState = ActivityManager.PROCESS_STATE_SERVICE;
}
if (app.hasShownUi && app != mHomeProcess) {
// If this process has shown some UI, let it immediately
// go to the LRU list because it may be pretty heavy with
// UI stuff. We'll tag it with a label just to help
// debug and understand what is going on.
if (adj > ProcessList.SERVICE_ADJ) {
app.adjType = "cch-started-ui-services";
}
} else {
if (now < (s.lastActivity + ActiveServices.MAX_SERVICE_INACTIVITY)) {
// This service has seen some activity within
// recent memory, so we will keep its process ahead
// of the background processes.
if (adj > ProcessList.SERVICE_ADJ) {
adj = ProcessList.SERVICE_ADJ;
app.adjType = "started-services";
app.cached = false;
}
}
// If we have let the service slide into the background
// state, still have some text describing what it is doing
// even though the service no longer has an impact.
if (adj > ProcessList.SERVICE_ADJ) {
app.adjType = "cch-started-services";
}
}
}
for (int conni = s.connections.size()-1;
conni >= 0 && (adj > ProcessList.FOREGROUND_APP_ADJ
|| schedGroup == Process.THREAD_GROUP_BG_NONINTERACTIVE
|| procState > ActivityManager.PROCESS_STATE_TOP);
conni--) {
ArrayList<ConnectionRecord> clist = s.connections.valueAt(conni);
for (int i = 0;
i < clist.size() && (adj > ProcessList.FOREGROUND_APP_ADJ
|| schedGroup == Process.THREAD_GROUP_BG_NONINTERACTIVE
|| procState > ActivityManager.PROCESS_STATE_TOP);
i++) {
// XXX should compute this based on the max of
// all connected clients.
ConnectionRecord cr = clist.get(i);
if (cr.binding.client == app) {
// Binding to ourself is not interesting.
continue;
}
if ((cr.flags&Context.BIND_WAIVE_PRIORITY) == 0) {
ProcessRecord client = cr.binding.client;
int clientAdj = computeOomAdjLocked(client, cachedAdj,
TOP_APP, doingAll, now);
int clientProcState = client.curProcState;
if (clientProcState >= ActivityManager.PROCESS_STATE_CACHED_ACTIVITY) {
// If the other app is cached for any reason, for purposes here
// we are going to consider it empty. The specific cached state
// doesn't propagate except under certain conditions.
clientProcState = ActivityManager.PROCESS_STATE_CACHED_EMPTY;
}
String adjType = null;
if ((cr.flags&Context.BIND_ALLOW_OOM_MANAGEMENT) != 0) {
// Not doing bind OOM management, so treat
// this guy more like a started service.
if (app.hasShownUi && app != mHomeProcess) {
// If this process has shown some UI, let it immediately
// go to the LRU list because it may be pretty heavy with
// UI stuff. We'll tag it with a label just to help
// debug and understand what is going on.
if (adj > clientAdj) {
adjType = "cch-bound-ui-services";
}
app.cached = false;
clientAdj = adj;
clientProcState = procState;
} else {
if (now >= (s.lastActivity
+ ActiveServices.MAX_SERVICE_INACTIVITY)) {
// This service has not seen activity within
// recent memory, so allow it to drop to the
// LRU list if there is no other reason to keep
// it around. We'll also tag it with a label just
// to help debug and undertand what is going on.
if (adj > clientAdj) {
adjType = "cch-bound-services";
}
clientAdj = adj;
}
}
}
if (adj > clientAdj) {
// If this process has recently shown UI, and
// the process that is binding to it is less
// important than being visible, then we don't
// care about the binding as much as we care
// about letting this process get into the LRU
// list to be killed and restarted if needed for
// memory.
if (app.hasShownUi && app != mHomeProcess
&& clientAdj > ProcessList.PERCEPTIBLE_APP_ADJ) {
adjType = "cch-bound-ui-services";
} else {
if ((cr.flags&(Context.BIND_ABOVE_CLIENT
|Context.BIND_IMPORTANT)) != 0) {
adj = clientAdj >= ProcessList.PERSISTENT_SERVICE_ADJ
? clientAdj : ProcessList.PERSISTENT_SERVICE_ADJ;
} else if ((cr.flags&Context.BIND_NOT_VISIBLE) != 0
&& clientAdj < ProcessList.PERCEPTIBLE_APP_ADJ
&& adj > ProcessList.PERCEPTIBLE_APP_ADJ) {
adj = ProcessList.PERCEPTIBLE_APP_ADJ;
} else if (clientAdj > ProcessList.VISIBLE_APP_ADJ) {
adj = clientAdj;
} else {
if (adj > ProcessList.VISIBLE_APP_ADJ) {
adj = ProcessList.VISIBLE_APP_ADJ;
}
}
if (!client.cached) {
app.cached = false;
}
adjType = "service";
}
}
if ((cr.flags&Context.BIND_NOT_FOREGROUND) == 0) {
if (client.curSchedGroup == Process.THREAD_GROUP_DEFAULT) {
schedGroup = Process.THREAD_GROUP_DEFAULT;
}
if (clientProcState <= ActivityManager.PROCESS_STATE_TOP) {
if (clientProcState == ActivityManager.PROCESS_STATE_TOP) {
// Special handling of clients who are in the top state.
// We *may* want to consider this process to be in the
// top state as well, but only if there is not another
// reason for it to be running. Being on the top is a
// special state, meaning you are specifically running
// for the current top app. If the process is already
// running in the background for some other reason, it
// is more important to continue considering it to be
// in the background state.
mayBeTop = true;
clientProcState = ActivityManager.PROCESS_STATE_CACHED_EMPTY;
} else {
// Special handling for above-top states (persistent
// processes). These should not bring the current process
// into the top state, since they are not on top. Instead
// give them the best state after that.
clientProcState =
ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND;
}
}
} else {
if (clientProcState <
ActivityManager.PROCESS_STATE_IMPORTANT_BACKGROUND) {
clientProcState =
ActivityManager.PROCESS_STATE_IMPORTANT_BACKGROUND;
}
}
if (procState > clientProcState) {
procState = clientProcState;
}
if (procState < ActivityManager.PROCESS_STATE_IMPORTANT_BACKGROUND
&& (cr.flags&Context.BIND_SHOWING_UI) != 0) {
app.pendingUiClean = true;
}
if (adjType != null) {
app.adjType = adjType;
app.adjTypeCode = ActivityManager.RunningAppProcessInfo
.REASON_SERVICE_IN_USE;
app.adjSource = cr.binding.client;
app.adjSourceProcState = clientProcState;
app.adjTarget = s.name;
}
}
if ((cr.flags&Context.BIND_TREAT_LIKE_ACTIVITY) != 0) {
app.treatLikeActivity = true;
}
final ActivityRecord a = cr.activity;
if ((cr.flags&Context.BIND_ADJUST_WITH_ACTIVITY) != 0) {
if (a != null && adj > ProcessList.FOREGROUND_APP_ADJ &&
(a.visible || a.state == ActivityState.RESUMED
|| a.state == ActivityState.PAUSING)) {
adj = ProcessList.FOREGROUND_APP_ADJ;
if ((cr.flags&Context.BIND_NOT_FOREGROUND) == 0) {
schedGroup = Process.THREAD_GROUP_DEFAULT;
}
app.cached = false;
app.adjType = "service";
app.adjTypeCode = ActivityManager.RunningAppProcessInfo
.REASON_SERVICE_IN_USE;
app.adjSource = a;
app.adjSourceProcState = procState;
app.adjTarget = s.name;
}
}
}
}
}
for (int provi = app.pubProviders.size()-1;
provi >= 0 && (adj > ProcessList.FOREGROUND_APP_ADJ
|| schedGroup == Process.THREAD_GROUP_BG_NONINTERACTIVE
|| procState > ActivityManager.PROCESS_STATE_TOP);
provi--) {
ContentProviderRecord cpr = app.pubProviders.valueAt(provi);
for (int i = cpr.connections.size()-1;
i >= 0 && (adj > ProcessList.FOREGROUND_APP_ADJ
|| schedGroup == Process.THREAD_GROUP_BG_NONINTERACTIVE
|| procState > ActivityManager.PROCESS_STATE_TOP);
i--) {
ContentProviderConnection conn = cpr.connections.get(i);
ProcessRecord client = conn.client;
if (client == app) {
// Being our own client is not interesting.
continue;
}
int clientAdj = computeOomAdjLocked(client, cachedAdj, TOP_APP, doingAll, now);
int clientProcState = client.curProcState;
if (clientProcState >= ActivityManager.PROCESS_STATE_CACHED_ACTIVITY) {
// If the other app is cached for any reason, for purposes here
// we are going to consider it empty.
clientProcState = ActivityManager.PROCESS_STATE_CACHED_EMPTY;
}
if (adj > clientAdj) {
if (app.hasShownUi && app != mHomeProcess
&& clientAdj > ProcessList.PERCEPTIBLE_APP_ADJ) {
app.adjType = "cch-ui-provider";
} else {
adj = clientAdj > ProcessList.FOREGROUND_APP_ADJ
? clientAdj : ProcessList.FOREGROUND_APP_ADJ;
app.adjType = "provider";
}
app.cached &= client.cached;
app.adjTypeCode = ActivityManager.RunningAppProcessInfo
.REASON_PROVIDER_IN_USE;
app.adjSource = client;
app.adjSourceProcState = clientProcState;
app.adjTarget = cpr.name;
}
if (clientProcState <= ActivityManager.PROCESS_STATE_TOP) {
if (clientProcState == ActivityManager.PROCESS_STATE_TOP) {
// Special handling of clients who are in the top state.
// We *may* want to consider this process to be in the
// top state as well, but only if there is not another
// reason for it to be running. Being on the top is a
// special state, meaning you are specifically running
// for the current top app. If the process is already
// running in the background for some other reason, it
// is more important to continue considering it to be
// in the background state.
mayBeTop = true;
clientProcState = ActivityManager.PROCESS_STATE_CACHED_EMPTY;
} else {
// Special handling for above-top states (persistent
// processes). These should not bring the current process
// into the top state, since they are not on top. Instead
// give them the best state after that.
clientProcState =
ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND;
}
}
if (procState > clientProcState) {
procState = clientProcState;
}
if (client.curSchedGroup == Process.THREAD_GROUP_DEFAULT) {
schedGroup = Process.THREAD_GROUP_DEFAULT;
}
}
// If the provider has external (non-framework) process
// dependencies, ensure that its adjustment is at least
// FOREGROUND_APP_ADJ.
if (cpr.hasExternalProcessHandles()) {
if (adj > ProcessList.FOREGROUND_APP_ADJ) {
adj = ProcessList.FOREGROUND_APP_ADJ;
schedGroup = Process.THREAD_GROUP_DEFAULT;
app.cached = false;
app.adjType = "provider";
app.adjTarget = cpr.name;
}
if (procState > ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND) {
procState = ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND;
}
}
}

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if (mayBeTop && procState > ActivityManager.PROCESS_STATE_TOP) {
// A client of one of our services or providers is in the top state. We
// *may* want to be in the top state, but not if we are already running in
// the background for some other reason. For the decision here, we are going
// to pick out a few specific states that we want to remain in when a client
// is top (states that tend to be longer-term) and otherwise allow it to go
// to the top state.
switch (procState) {
case ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND:
case ActivityManager.PROCESS_STATE_IMPORTANT_BACKGROUND:
case ActivityManager.PROCESS_STATE_SERVICE:
// These all are longer-term states, so pull them up to the top
// of the background states, but not all the way to the top state.
procState = ActivityManager.PROCESS_STATE_IMPORTANT_FOREGROUND;
break;
default:
// Otherwise, top is a better choice, so take it.
procState = ActivityManager.PROCESS_STATE_TOP;
break;
}
}
if (procState >= ActivityManager.PROCESS_STATE_CACHED_EMPTY) {
if (app.hasClientActivities) {
// This is a cached process, but with client activities. Mark it so.
procState = ActivityManager.PROCESS_STATE_CACHED_ACTIVITY_CLIENT;
app.adjType = "cch-client-act";
} else if (app.treatLikeActivity) {
// This is a cached process, but somebody wants us to treat it like it has
// an activity, okay!
procState = ActivityManager.PROCESS_STATE_CACHED_ACTIVITY;
app.adjType = "cch-as-act";
}
}
if (adj == ProcessList.SERVICE_ADJ) {
if (doingAll) {
app.serviceb = mNewNumAServiceProcs > (mNumServiceProcs/3);
mNewNumServiceProcs++;
//Slog.i(TAG, "ADJ " + app + " serviceb=" + app.serviceb);
if (!app.serviceb) {
// This service isn't far enough down on the LRU list to
// normally be a B service, but if we are low on RAM and it
// is large we want to force it down since we would prefer to
// keep launcher over it.
if (mLastMemoryLevel > ProcessStats.ADJ_MEM_FACTOR_NORMAL
&& app.lastPss >= mProcessList.getCachedRestoreThresholdKb()) {
app.serviceHighRam = true;
app.serviceb = true;
//Slog.i(TAG, "ADJ " + app + " high ram!");
} else {
mNewNumAServiceProcs++;
//Slog.i(TAG, "ADJ " + app + " not high ram!");
}
} else {
app.serviceHighRam = false;
}
}
if (app.serviceb) {
adj = ProcessList.SERVICE_B_ADJ;
}
}
app.curRawAdj = adj;
//Slog.i(TAG, "OOM ADJ " + app + ": pid=" + app.pid +
// " adj=" + adj + " curAdj=" + app.curAdj + " maxAdj=" + app.maxAdj);
if (adj > app.maxAdj) {
adj = app.maxAdj;
if (app.maxAdj <= ProcessList.PERCEPTIBLE_APP_ADJ) {
schedGroup = Process.THREAD_GROUP_DEFAULT;
}
}
// Do final modification to adj. Everything we do between here and applying
// the final setAdj must be done in this function, because we will also use
// it when computing the final cached adj later. Note that we don't need to
// worry about this for max adj above, since max adj will always be used to
// keep it out of the cached vaues.
app.curAdj = app.modifyRawOomAdj(adj);
app.curSchedGroup = schedGroup;
app.curProcState = procState;
app.foregroundActivities = foregroundActivities;
return app.curRawAdj;

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