提高进程优先级，降低被low memory killer杀死的机
2019-08-14 本文已影响0人
DD_Dog
在项目中遇到服务被偶然杀死的问题，通过kernel log看到：
lowmem_shrink: 5 callbacks suppressed
lowmemorykiller: [ pid ] uid tgid total_vm rss swap cpu oom_score_adj name
lowmemorykiller: [ 121] 0 121 131 38 18 0 -941 ueventd
lowmemorykiller: [ 128] 1023 128 884 65 30 0 -941 sdcard
lowmemorykiller: [ 129] 0 129 358 31 4 1 -941 healthd
lowmemorykiller: [ 130] 1000 130 254 44 15 0 -941 servicemanager
lowmemorykiller: [ 131] 0 131 1171 73 69 0 -941 vold
lowmemorykiller: [ 132] 1000 132 786 53 21 0 -941 download
lowmemorykiller: [ 133] 1000 133 767 42 36 1 -941 modem_control
lowmemorykiller: [ 134] 1000 134 1540 48 40 0 -941 modemd
lowmemorykiller: [ 135] 1000 135 1334 56 51 0 -941 wcnd
lowmemorykiller: [ 136] 1000 136 90 3 3 0 -941 batterysrv
lowmemorykiller: [ 137] 1000 137 749 40 30 0 -941 modemDriver_vpa
lowmemorykiller: [ 138] 0 138 2452 89 84 1 -941 netd
lowmemorykiller: [ 143] 0 143 284 43 34 1 -941 debuggerd
lowmemorykiller: [ 144] 0 144 1509 150 47 0 -941 slog
lowmemorykiller: [ 146] 1000 146 11892 920 124 0 -941 surfaceflinger
lowmemorykiller: [ 147] 0 147 51702 2089 1565 0 -941 zygote
lowmemorykiller: [ 148] 1019 148 2949 159 172 0 -941 drmserver
lowmemorykiller: [ 149] 1013 149 12314 345 537 0 -941 mediaserver
lowmemorykiller: [ 150] 1012 150 251 47 32 1 -941 installd
lowmemorykiller: [ 151] 1017 151 842 62 80 1 -941 keystore
lowmemorykiller: [ 153] 2000 153 328 62 63 0 -941 slogmodem
lowmemorykiller: [ 154] 0 154 267 35 30 0 -941 srtd
lowmemorykiller: [ 155] 1000 155 1456 96 63 0 -941 thermald
lowmemorykiller: [ 162] 0 162 267 25 31 1 -941 srtd
lowmemorykiller: [ 164] 1000 164 7750 116 107 0 -941 phoneserver
lowmemorykiller: [ 165] 0 165 3723 201 299 1 -941 engpc
lowmemorykiller: [ 166] 1001 166 2728 168 49 1 -941 rild_sp
lowmemorykiller: [ 170] 1001 170 2459 141 46 1 -941 rild_sp
lowmemorykiller: [ 171] 0 171 1308 88 765 1 -941 cp_diskserver
lowmemorykiller: [ 172] 2000 172 234 31 29 0 -941 sh
lowmemorykiller: [ 175] 0 175 2927 91 260 0 -941 engpc
lowmemorykiller: [ 179] 1023 179 884 53 46 1 -941 sdcard
lowmemorykiller: [ 182] 0 182 1380 58 62 0 -941 collect_apr
lowmemorykiller: [ 183] 1000 183 799 49 40 1 -941 refnotify
lowmemorykiller: [ 561] 1000 561 83930 5461 2529 0 -941 system_server
lowmemorykiller: [ 629] 1001 629 83097 5956 1728 0 -705 m.android.phone
lowmemorykiller: [ 639] 10035 639 61751 4469 1329 0 -705 ndroid.systemui
lowmemorykiller: [ 716] 10029 716 53242 1687 1869 0 58 android.smspush
lowmemorykiller: [ 759] 10014 759 56097 3128 1370 0 294 d.process.acore
lowmemorykiller: [ 777] 10040 777 60884 3855 1364 0 0 ndroid.incallui
lowmemorykiller: [ 792] 1000 792 53277 1435 2135 1 -705 eadst.validator
lowmemorykiller: [ 799] 10000 799 54030 1440 2137 0 -705 oid.modemassert
lowmemorykiller: [ 1036] 2000 1036 892 42 7 1 -941 adbd
lowmemorykiller: [ 5576] 10039 5576 55422 3100 1298 0 470 yscale.atclient
lowmemorykiller: [ 5982] 10013 5982 54468 3466 1259 1 529 com.svox.pico
lowmemorykiller: [ 6022] 1000 6022 7750 116 107 0 -941 phoneserver
lowmemorykiller: Killing 'com.svox.pico' (5982), adj 9,
lowmemorykiller: Killing 'yscale.atclient' (5576), adj 8, //这是我的应用包名，显示的不全
lowmemorykiller: Killing 'oadcastreceiver' (6139), adj 9,
lowmemorykiller: Killing 'com.android.mms' (6096), adj 9,
从Log中看到我应用的adj等级为8，所以需要降低这个值，越小越不容易被杀死。
方法一
在代码里面调用 startForeground/stopForeground 添加为前台程序/去掉前台程序
//在onCreate()/onStartCommand()方法
/**
* 设置前台进程
*/
private void startForegournd() {
Notification notification = new Notification();
Intent notificationIntent = new Intent(this, MainActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, notificationIntent, 0);
//把该service创建为前台service
startForeground(8888, notification);
}
//onDestory()方法
stopForeground(true);
方法二
设置为系统应用
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
android:persistent="true"
android:sharedUserId="android.uid.system"
package="com.flyscale.atclient">
设置好后，查看adj值，方法如下：
//oom_adj代表当前进程的优先级，这个优先级是kernel中的优先级
adb shell
shell@sp9820w_modem:/ $ ps
u0_a39 798 146 243272 17252 ffffffff 00000000 S com.flyscale.atclient
//pid为798
shell@sp9820w_modem:/ $ cat proc/798/oom_adj
1 //adj值变为1了
其它命令
查看低内存管理的adj值及对应的内存限值
shell@sp9820w_modem:/ $ cat /sys/module/lowmemorykiller/parameters/adj
0,1,2,3,9,15 //说明的系统分为0,1,2,3,9,15这7个等级，为什么是7个？因为这几个值只是一个分界线
越小越难被杀死，前台程序是0，init进程是-16。在init.rc里面有这样一句话 write /proc/1/oom_adj -16
上面的等级对应的低内存回收极限可以通过下面的命令查看
shell@sp9820w_modem:/ $ cat /sys/module/lowmemorykiller/parameters/minfree
2560,3840,4608,6144,7680,9216
例如：当内存低于9216时，会杀掉adj>=15的进程
- 对每个进程来说：
/proc/pid/oom_adj：代表当前进程的优先级，这个优先级是kernel中的优先级，这个优先级与上层的优先级之间有一个换算。
/proc/pid/oom_score_adj：上层优先级，跟ProcessList中的优先级对应
