Zram not compressing data

Support Kernel
1

after installing systemd-swap and enabling zram. data entering zram is not compressed. and also the amount of data in zram that I receive with the “cat / sys / block / zram (0-1) / mm_stat” command is less than the amount of data received with the “swapon - -show” command. what could be the problem? why is the data not compressed? how can this be fixed?

2

Maybe your original data is already compressed?

Can you paste the contents of mm_stat file?

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[victor@ ~]$ swapon --show
NAME       TYPE        SIZE  USED  PRIO
/dev/zram0 partition 391,8M 34,1M 32767
/dev/zram1 partition 391,8M 34,2M 32767
[victor@ ~]$ cat /sys/block/zram0/mm_stat 
17539072 17535034 17539072        0 17539072        0        0     4281
[victor@ ~]$ cat /sys/block/zram1/mm_stat 
18698240 18694202 18698240        0 18698240        0        0     4564
4

I did some tests and found that the data is actually being compressed, the information in the mm_stat file is displayed incorrectly. it looks like a bug. and on another distribution on the same version of the kernel, I did not notice such behavior.

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5

Great catch! Can you post mm_stat from the other distribution?

6

From Void Linux 5.8

murloc@~$ swapon --show
NAME       TYPE      SIZE   USED PRIO
/dev/zram0 partition 512M 118,8M   10
/dev/zram1 partition 512M   119M   10
murloc@~$ cat /sys/block/zram0/mm_stat 
124260352 29869704 31735808        0 82841600     3314      600      568
murloc@~$ cat /sys/block/zram1/mm_stat 
124719104 29537634 31158272        0 31510528     3510       51      571
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