mercredi 25 février 2015

[Troubleshooting]No more random Freezes & Reboot topic






Many of you (and I) experienced random freezes & reboots but found no solutions, even after flashing so many different ROMs.
Hopefully I've found the cause & the SOLUTION.

I've been flashing custom ROM from the first time I own a gadget but recently after I flash Gnabo 8 I experienced something strange: Random Freezes & Reboots.
In my case, random reboots occur after 31 hours of usage.
After I analyzed the problem I concluded that the cause is rogue apps running in the background & hogging the CPU to an extend that the device can't be used anymore.
Then the freezes & reboots occur.
After 1 month of analyzing further, I found 3 processes in my N8000 that become the Prime Suspects:
  1. System Server

  2. dhd_dcp

  3. kswapd0


I consulted to Andi (Lord Boeffla) & Mikyno about this before eliminating the PRIME SUSPECTS to just 1 rogue app.
My knowledge in Linux + Google come handy in this matter & concluded that kswapd0 is the cause(?)
kswapd0 is responsible for creating swap file a.k.a virtual memory in case the real RAM is not enough.
In Linux, there is a separate partition that is dedicated for virtual memory a.k.a swap partition but in android, specially our N80XX, I can't find any swap partition.

How come kswapd0 active & consume so much CPU time & causing freezes+reboots where there is no swap partition?

Further researches bring me these information:
  • In my current ROM (ARHD 21.0) my sysctl.conf is empty, BUT...

  • using Android Tuner, I find that vm.swappiness is 130!!
    vm.swappiness is a setting value to control kswapd0 on when to write the RAM content into disk/internal memory.
    vm.swappiness=0 is to tell to avoid writing to disk/internal memory as much as possible.
    vm.swappiness=100 is to tell to write to disk/internal memory as much as possible (avoiding RAM).


I don't know how the sysctl.conf is empty but the vm.swappiness=130 is set, but I modified it to vm.swappiness=0.
Then I reboot my N8000.

Now my N8000 is running without incidents for 3 days & 20 hours straight.
I hope this is the final solution I wanted & I also hope that this information can help others with the same problem too.






1 commentaire:

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