SWT／ANR问题－－Dump时间过长导致的SWT

1.确认问题时间点：

05-07 03:15:53.220  1150  2238 I watchdog: Blocked in handler on ActivityManager (ActivityManager)
block module: ActivityManager      timeout: 60s

2. 查看时间段内对应线程的 call stack，两次trace是一致的，如下：

从system_server blocked的thread入手分析，此题是ActivityManager

----- pid 1150 at 2019-05-07 03:15:22 -----
Cmd line: system_server
"ActivityManager" prio=5 tid=13 Native
  | group="main" sCount=1 dsCount=0 flags=1 obj=0x15040828 self=0xa7ebb400
  | sysTid=1166 nice=-2 cgrp=default sched=0/0 handle=0x97980970
  | state=S schedstat=( 450054758690 793897362594 812502 ) utm=20997 stm=24008 core=3 HZ=100
  | sta