Funny, it happened even on TCL website. I wanted to read about the phones. Especially this one
https://www.tcl.com/ch/de/tcl-for-her just open it and move a bit up and down
Ok, I've done some digging. I enabled developer settings, connected log output to my PC and started adb shell.
Indeed, the phone is not dead when it's frozen. The GPU has problems drawing due to low memory, prints some errors periodically. The log is flooded with lowmemorykiller messages too.
Then I started top, the CPU was busy swapping
Quote:
Tasks: 607 total, 1 running, 606 sleeping, 0 stopped, 0 zombie
Mem: 3959620K total, 3463176K used, 496444K free, 800K buffers
Swap: 2177784K total, 1055232K used, 1122552K free, 117496K cached
800%cpu 5%user 0%nice 107%sys 238%idle 450%iow 0%irq 0%sirq 0%host
PID USER PR NI VIRT RES SHR S[%CPU] %MEM TIME+ ARGS
151 root 20 0 0 0 0 D 24.1 0.0 6:01.81 [kswapd0]
460 root 0 -20 0 0 0 D 11.2 0.0 1:38.81 [kworker/u18:2+kblockd]
4841 u0_a243 10 -10 42G 9.2M 9.2M D 6.6 0.2 1:14.12 com.microsoft.emmx
128 root 20 0 0 0 0 D 6.2 0.0 0:20.99 [kworker/u16:1+kverityd]
1421 system 20 0 6.5G 208K 208K S 4.9 0.0 0:15.88 com.tcl.guard
7 root 20 0 0 0 0 I 4.9 0.0 0:18.69 [kworker/u16:0-kverityd]
6263 shell 20 0 2.1G 2.8M 2.1M R 3.9 0.0 0:04.05 top
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so I checked memory usage
Quote:
Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.2G 497M 292K 736K
-/+ buffers/cache: 3.2G 498M
Swap: 2.0G 1.0G 1.0G
Eternals11:/ $
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I let it go like that but eventually de device rebooted, after ~30 min.
Next I tried to monitor memory usage, whilst opening the TCL website.
Quote:
Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.6G 133M 13M 20M
-/+ buffers/cache: 3.6G 152M
Swap: 2.0G 151M 1.9G
1|Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.7G 26M 33M 2.0M
-/+ buffers/cache: 3.7G 28M
Swap: 2.0G 570M 1.5G
Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.6G 172M 32M 1.2M
-/+ buffers/cache: 3.6G 174M
Swap: 2.0G 490M 1.5G
Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.5G 193M 16M 1.6M
-/+ buffers/cache: 3.5G 195M
Swap: 2.0G 548M 1.5G
Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.7G 66M 23M 1.9M
-/+ buffers/cache: 3.7G 68M
Swap: 2.0G 589M 1.5G
Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.5G 280M 11M 2.1M
-/+ buffers/cache: 3.5G 282M
Swap: 2.0G 579M 1.5G
Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.6G 95M 37M 2.2M
-/+ buffers/cache: 3.6G 97M
Swap: 2.0G 621M 1.4G
Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.4G 289M 11M 1.0M
-/+ buffers/cache: 3.4G 290M
Swap: 2.0G 735M 1.3G
Eternals11:/ $ free -h
total used free shared buffers
Mem: 3.7G 3.2G 521M 236K 732K
-/+ buffers/cache: 3.2G 521M
Swap: 2.0G 1.0G 1.0G
Eternals11:/ $
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When it reach 1GB of swap usage the screen freezes and a lot of issues are being logged.
I've never experienced such situation with Android device. I remember having Samsung phone with 1GB RAM, where apps where often crashing, but not freezing the phone. Seeing swap here really intrigued me. TCL is advertising for some phones things like 8+8GB RAM which means using swap partition, but they don't specify that for this tablet. Anyway, I was wondering what if I disable the swap, but I couldn't. swapoff requires a device as parameter, but I was not allowed to read the swap config. Then I've read that this could be a compressed RAM in fact, so I also tried to disable it with no success as well
Quote:
Eternals11:/ $ cat /proc/swaps
cat: /proc/swaps: Permission denied
1|Eternals11:/ $ ls /dev/block/zram0
/dev/block/zram0
Eternals11:/ $ swapoff /dev/block/zram0
swapoff: failed to remove swaparea: Operation not permitted
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Well, but I've learned what's the limitation of this device, so I went over my installed apps and removed things which works in background, mainly mail and IM clients. It helped a lot. That one TCL website is still freezing it in msedge (but not in chrome), though I haven't found any other case so far. I think there's something wrong with the firmware configuration, maybe it starts cleaning the memory too late (after too high threshold) so it can fall into a trap when apps use all memory leaving too late for the garbage collector or lowmemorykiller etc to work properly.
I guess I'll use it then for the main purpose I bought it: to read books and online news.
EDIT:
If anyone is curious, I haven't seen the swap using more than 1GB. I've tried 2 or 3 times. Half full swap makes UI freeze, and it's a point of no recovery.