android进程死于(adj *)，什么是adj？

Question

在我的 Galaxy S III 上，使用 logcat 我可以经常看到该进程终止。

(adj 5)、(adj 8)、(adj 9) 和 (adj 10) 是什么意思？

以下是设备 logcat :-

I/ActivityManager( 2258): Process com.google.android.partnersetup (pid 32242) (adj 10) has died.

I/ActivityManager( 2258): Process com.metago.astro (pid 32446) (adj 10) has died.

D/dalvikvm(32602): WAIT_FOR_CONCURRENT_GC blocked 0ms
I/ActivityManager( 2258): Process com.google.android.gms (pid 32272) (adj 10) has died.

I/ActivityManager( 2258): Process com.whatsapp (pid 12041) (adj 8) has died.

D/KeyguardViewMediator( 2258): setHidden false
D/WindowManager( 2258): mInputFocus is not null.
I/ActivityManager( 2258): Process com.sec.spp.push (pid 19839) (adj 8) has died.

I/ActivityManager( 2258): Process com.test.happ.jiffy (pid 556) (adj 5) has died.

Answer 1

当内存不足时，android系统会杀掉一些后台进程，每个进程都有一个adj值代表它的重要性。 adj 值越低，过程的重要性越高。高级 adj 进程将首先被杀死。

ProcessList.java 中定义的值

class ProcessList {
    // The minimum time we allow between crashes, for us to consider this
    // application to be bad and stop and its services and reject broadcasts.
    static final int MIN_CRASH_INTERVAL = 60*1000;

    // OOM adjustments for processes in various states:

    // This is a process only hosting activities that are not visible,
    // so it can be killed without any disruption.
    static final int HIDDEN_APP_MAX_ADJ = 15;
    static int HIDDEN_APP_MIN_ADJ = 9;

    // The B list of SERVICE_ADJ -- these are the old and decrepit
    // services that aren't as shiny and interesting as the ones in the A list.
    static final int SERVICE_B_ADJ = 8;

    // This is the process of the previous application that the user was in.
    // This process is kept above other things, because it is very common to
    // switch back to the previous app.  This is important both for recent
    // task switch (toggling between the two top recent apps) as well as normal
    // UI flow such as clicking on a URI in the e-mail app to view in the browser,
    // and then pressing back to return to e-mail.
    static final int PREVIOUS_APP_ADJ = 7;

    // This is a process holding the home application -- we want to try
    // avoiding killing it, even if it would normally be in the background,
    // because the user interacts with it so much.
    static final int HOME_APP_ADJ = 6;

更多关于android内存管理可以引用http://developer.android.com/guide/components/processes-and-threads.html