1. 背景
测试在正常操作车机的时候，出现了：唤醒车机时娱乐屏出现连续两次黑屏，且发现系统有卡顿的现象。
2. log分析
- low_memory_killer 杀掉adj=100的visible进程，是因为memory 不足导致的。
行 16839: 10-26 16:22:11.900235 264 264 I lowmemorykiller: Kill 'com.bilibili.bilithings:ijkservice' (19543), uid 10045, oom_adj 200 to free 65668kB
行 16840: 10-26 16:22:11.900316 264 264 I lowmemorykiller: Reclaimed 65668kB, cache(209812kB) and free(52500kB)-reserved(150240kB) below min(224692kB) for oom_adj 200
行 16854: 10-26 16:22:11.918705 264 264 I lowmemorykiller: Kill 'com.android.inputmethod' (15307), uid 10020, oom_adj 200 to free 55604kB
行 16855: 10-26 16:22:11.918735 264 264 I lowmemorykiller: Reclaimed 55604kB, cache(209292kB) and free(73144kB)-reserved(150240kB) below min(224692kB) for oom_adj 200
行 17672: 10-26 16:22:12.369378 264 264 W lowmemorykiller: Failed to open /proc/11439/oom_score_adj; errno=2: process 11439 might have been killed
行 18564: 10-26 16:22:12.916724 264 264 I lowmemorykiller: Reclaimed 0kB, cache(234016kB) and free(19076kB)-reserved(150240kB) below min(262144kB) for oom_adj 250
行 18565: 10-26 16:22:12.916832 264 264 I lowmemorykiller: Suppressed 90 failed kill reports
行 19690: 10-26 16:22:13.882001 264 264 I lowmemorykiller: Kill 'com.android.launcher' (2036), uid 1000, oom_adj 100 to free 493428kB
行 19691: 10-26 16:22:13.882084 264 264 I lowmemorykiller: Reclaimed 493428kB, cache(186928kB) and free(12132kB)-reserved(150240kB) below min(187244kB) for oom_adj 100
行 19692: 10-26 16:22:13.882106 264 264 I lowmemorykiller: Suppressed 29 failed kill reports
行 19704: 10-26 16:22:13.887833 264 264 I lowmemorykiller: Kill 'com.android.media' (2937), uid 10029, oom_adj 100 to free 226284kB
行 19705: 10-26 16:22:13.887862 264 264 I lowmemorykiller: Reclaimed 226284kB, cache(183808kB) and free(13916kB)-reserved(150240kB) below min(187244kB) for oom_adj 100
行 20857: 10-26 16:22:14.882659 264 264 I lowmemorykiller: Reclaimed 0kB, cache(237948kB) and free(12096kB)-reserved(150240kB) below min(262144kB) for oom_adj 250
行 20858: 10-26 16:22:14.882715 264 264 I lowmemorykiller: Suppressed 94 failed kill reports
行 21610: 10-26 16:22:15.763508 264 264 I lowmemorykiller: Kill 'com.android.local.scene' (3278), uid 1000, oom_adj 100 to free 136676kB
行 21611: 10-26 16:22:15.763572 264 264 I lowmemorykiller: Reclaimed 136676kB, cache(185368kB) and free(13676kB)-reserved(150240kB) below min(187244kB) for oom_adj 100
行 21612: 10-26 16:22:15.763594 264 264 I lowmemorykiller: Suppressed 3 failed kill reports
行 22183: 10-26 16:22:16.463138 264 264 I lowmemorykiller: Kill 'com.android.energycenter' (3254), uid 10030, oom_adj 100 to free 119084kB
行 22184: 10-26 16:22:16.463160 264 264 I lowmemorykiller: Reclaimed 119084kB, cache(183628kB) and free(13204kB)-reserved(150240kB) below min(187244kB) for oom_adj 100
行 22185: 10-26 16:22:16.463167 264 264 I lowmemorykiller: Suppressed 64 failed kill reports
行 22193: 10-26 16:22:16.477960 264 264 I lowmemorykiller: Kill 'com.android.btphone' (2126), uid 10028, oom_adj 100 to free 67280kB
行 22194: 10-26 16:22:16.477977 264 264 I lowmemorykiller: Reclaimed 67280kB, cache(180636kB) and free(34372kB)-reserved(150240kB) below min(187244kB) for oom_adj 100
行 22199: 10-26 16:22:16.481801 264 264 I lowmemorykiller: Kill 'com.android.carplay' (2446), uid 1000, oom_adj 100 to free 66228kB
行 22200: 10-26 16:22:16.481822 264 264 I lowmemorykiller: Reclaimed 66228kB, cache(178556kB) and free(39916kB)-reserved(150240kB) below min(187244kB) for oom_adj 100
行 22219: 10-26 16:22:16.499102 264 264 I lowmemorykiller: Kill 'com.android.permissioncontroller' (2322), uid 10043, oom_adj 100 to free 63492kB
行 22220: 10-26 16:22:16.499117 264 264 I lowmemorykiller: Reclaimed 63492kB, cache(172056kB) and free(99560kB)-reserved(150240kB) below min(187244kB) for oom_adj 100
行 22230: 10-26 16:22:16.515621 264 264 I lowmemorykiller: Kill 'android.ext.services' (1731), uid 10039, oom_adj 100 to free 54652kB
行 22231: 10-26 16:22:16.515644 264 264 I lowmemorykiller: Reclaimed 54652kB, cache(167376kB) and free(118736kB)-reserved(150240kB) below min(187244kB) for oom_adj 100
行 22289: 10-26 16:22:16.535189 264 264 I lowmemorykiller: Kill 'com.android.linkmanager' (2296), uid 1000, oom_adj 100 to free 52544kB
从/android/frameworks/base/services/core/java/com/android/server/am/ProcessList.java
可以看到adj=100的定义：VISIBLE_APP_ADJ，从google的描述来看，adj=100的进程是可见activity对应的进程，不应被杀掉。
// This is a process bound by the system (or other app) that's more important than services but
// not so perceptible that it affects the user immediately if killed.
public static final int PERCEPTIBLE_LOW_APP_ADJ = 250;
// This is a process hosting services that are not perceptible to the user but the
// client (system) binding to it requested to treat it as if it is perceptible and avoid killing
// it if possible.
public static final int PERCEPTIBLE_MEDIUM_APP_ADJ = 225;
// This is a process only hosting components that are perceptible to the
// user, and we really want to avoid killing them, but they are not
// immediately visible. An example is background music playback.
public static final int PERCEPTIBLE_APP_ADJ = 200;
// This is a process only hosting activities that are visible to the
// user, so we'd prefer they don't disappear.
public static final int VISIBLE_APP_ADJ = 100;
static final int VISIBLE_APP_LAYER_MAX = PERCEPTIBLE_APP_ADJ - VISIBLE_APP_ADJ - 1;
// This is a process that was recently TOP and moved to FGS. Continue to treat it almost
// like a foreground app for a while.
// @see TOP_TO_FGS_GRACE_PERIOD
public static final int PERCEPTIBLE_RECENT_FOREGROUND_APP_ADJ = 50;
// This is the process running the current foreground app. We'd really
// rather not kill it!
public static final int FOREGROUND_APP_ADJ = 0;
// This is a process that the system or a persistent process has bound to,
// and indicated it is important.
public static final int PERSISTENT_SERVICE_ADJ = -700;
- log进程占用内存过大触发low memory
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 1650301: logmgr (pid 855) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 77679: surfaceflinger (pid 497) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 58900: logd (pid 263) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 16023: [email protected] (pid 428) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 15327: media.extractor (pid 764) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 13763: audioserver (pid 486) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 12345: media.metrics (pid 767) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 11470: zygote (pid 389) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 10143: webview_zygote (pid 1542) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 7932: mediaserver (pid 769) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 7912: media.swcodec (pid 781) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 7103: cameraserver (pid 742) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 6721: [email protected] (pid 442) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 6605: android.hardware.audio.service (pid 274) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 6383: init (pid 1) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 6122: zygote64 (pid 388) native
10-26 16:22:13.489428 1111 11527 I ActivityManager: ntv ?? 5720: media.hwcodec (pid 462) native
- Log V等级的log大量打印，导致logd进程来不及输出，占用内存所致。
行 89: 10-26 16:22:02.900211 622 16572 V tbox_client: wait heartbeat signal timeout
行 92: 10-26 16:22:02.900295 622 16572 V tbox_client: BaseMessageInterface
行 93: 10-26 16:22:02.900319 622 16572 V tbox_client: init BaseMessageInterface new message:0xb400007665043780 data:0xb4000076e50310b0
行 94: 10-26 16:22:02.900575 622 16572 V tbox_client: wait for heartbeat signal
行 98: 10-26 16:22:02.900927 622 16123 V tbox_client: ~BaseMessageInterface ~BaseMessageInterface delete message:0xb400007665043780 data:0xb4000076e50310b0
行 101: 10-26 16:22:02.901545 428 16144 V ANDROID_SOMEIP: SOME/IP-RM [0x0000] received message [NOTIFICATION] on service [0x0301:0x8003:0x0001]
行 102: 10-26 16:22:02.901622 428 16144 V ANDROID_SOMEIP: Received [NOTIFICATION] message from Client [0x0000] for a Service [0x0301:0x0001] Method [0x8003] with len [33]
行 103: 10-26 16:22:02.901638 428 16144 V ANDROID_SOMEIP: SOME/IP-SA received message [2] on Service [0x0301:0x0001:0x8003] client [0x0000] len [1]
行 104: 10-26 16:22:02.901755 428 508 V -BIND : [COM Callback: 0x0301:0x0001:0x8003]
行 106: 10-26 16:22:02.902100 428 16144 V ANDROID_SOMEIP: SOME/IP-RM [0x0000] received message [NOTIFICATION] on service [0x0302:0x8001:0x0001]
行 107: 10-26 16:22:02.902137 428 16144 V ANDROID_SOMEIP: Received [NOTIFICATION] message from Client [0x0000] for a Service [0x0302:0x0001] Method [0x8001] with len [103]
行 108: 10-26 16:22:02.902202 428 16144 V ANDROID_SOMEIP: SOME/IP-SA received message [2] on Service [0x0302:0x0001:0x8001] client [0x0000] len [71]
行 109: 10-26 16:22:02.902270 428 508 V -BIND : [COM Callback: 0x0302:0x0001:0x8001]
行 211: 10-26 16:22:02.941557 428 16144 V ANDROID_SOMEIP: SOME/IP-RM [0x0000] received message [NOTIFICATION] on service [0x0302:0x8001:0x0001]
行 212: 10-26 16:22:02.941629 428 16144 V ANDROID_SOMEIP: Received [NOTIFICATION] message from Client [0x0000] for a Service [0x0302:0x0001] Method [0x8001] with len [103]
行 213: 10-26 16:22:02.941647 428 16144 V ANDROID_SOMEIP: SOME/IP-SA received message [2] on Service [0x0302:0x0001:0x8001] client [0x0000] len [71]
行 214: 10-26 16:22:02.941731 428 16144 V ANDROID_SOMEIP: SOME/IP-RM [0x0000] received message [NOTIFICATION] on service [0x0301:0x8003:0x0001]
行 215: 10-26 16:22:02.941753 428 16144 V ANDROID_SOMEIP: Received [NOTIFICATION] message from Client [0x0000] for a Service [0x0301:0x0001] Method [0x8003] with len [33]
行 216: 10-26 16:22:02.941762 428 16144 V ANDROID_SOMEIP: SOME/IP-SA received message [2] on Service [0x0301:0x0001:0x8003] client [0x0000] len [1]
行 217: 10-26 16:22:02.941828 428 508 V -BIND : [COM Callback: 0x0301:0x0001:0x8003]
行 219: 10-26 16:22:02.941961 428 508 V -BIND : [COM Callback: 0x0302:0x0001:0x8001]
行 286: 10-26 16:22:02.964688 1111 1156 V SettingsProvider: callingUid=1000 call([settings, PUT_global, android_car_info_driving_speed, Bundle[{_user=0, value=48}]]) = null
行 293: 10-26 16:22:02.967693 1111 11173 V SettingsProvider: callingUid=1000 call([settings, GET_global, dropbox_age_seconds, null]) = Bundle[{value=null}]
行 295: 10-26 16:22:02.967786 1111 11173 V SettingsProvider: callingUid=1000 call([settings, GET_global, dropbox_max_files, null]) = Bundle[{value=null}]
行 297: 10-26 16:22:02.967866 1111 11173 V SettingsProvider: callingUid=1000 call([settings, GET_global, dropbox_quota_percent, null]) = Bundle[{value=null}]
行 298: 10-26 16:22:02.968010 1111 11173 V SettingsProvider: callingUid=1000 call([settings, GET_global, dropbox_reserve_percent, null]) = Bundle[{value=null}]
行 300: 10-26 16:22:02.968181 1111 11173 V SettingsProvider: callingUid=1000 call([settings, GET_global, dropbox_quota_kb, null]) = Bundle[{value=null}]
行 311: 10-26 16:22:02.971871 1111 5423 V SettingsProvider: callingUid=1000 call([settings, GET_global, com.android.assistant.full_wakeup_free.enable, null]) = Bundle[{value=null}]
行 313: 10-26 16:22:02.972473 1111 17082 V SettingsProvider: callingUid=1000 call([settings, GET_global, driving_video_limit_key, null]) = Bundle[{value=0}]
- logd输出如下log表示logd出现了内存不足的情况：
行 1503: 10-26 16:22:03.451576 0 0 D logd : Kicking blocked reader, pid 855, from LogBuffer::kickMe()
行 1508: 10-26 16:22:03.452153 0 0 D logd : Kicking blocked reader, pid 855, from LogBuffer::kickMe()
3. 修改方案
- 精简log V的log
- 工程模式去掉log V的调整入口，不让测试或者正常用户使用。