SWT / anr problem - SWT causes low memory killer (LMK)

Problem description ：

This is one that can be reproduced by stability tests in one day SWT problem , The probability of 30%.

according to SWT trace .txt and log, When the software watchdog occurs , Some threads are randomly blocked and blocked in different code , But about 9 Seconds later , The blocked thread enters the idle state . We suspect that the software watchdog is caused by the poor performance of the whole mobile phone .

When this SWT Trigger when it happens  memory dumps. Checked memory information , Low free memory , Normal cache memory . There are many for low priority processes in the kernel log LMK journal .

Problem analysis ：

from logcat In the log , This SWT Threaded “android.fg”,“android.ui” and “android.display”.

According to the trace log , Threads “android.fg” and “android.ui " was waiting to lock " 0x0ecf3bbc " hold by thread " ActivityManager ", This is waiting for locking " 0x0f3257a8 " hold by thread "android.bg” Call non duplicate functions Process.readProcFile(). about 9 Seconds later , stay “WATCHDOG KILLING” In the log , All blocked threads are waiting for the new task to be ready .

Lock waiting sequence of thread

Thread "main"-> "ActivityManager"(lock:0x0ecf3bbc)->"android.bg"(lock:0x0f3257a8) 
"android.ui"-> "ActivityManager"(lock:0x0ecf3bbc)-> "android.bg"(lock:0x0f3257a8)

Log analysis ÿ