Re: [PATCH v2 0/1] mm/swapfile.c: select the swap device with default priority round robin

[Baoquan He <bhe@redhat.com>]

On 09/26/25 at 11:55pm, Baoquan He wrote:
> The detailed information about patch can be found in patch log. Here I
> would like to add testing related information.
> 
>  On my system, it has 8 nodes, 64G RAM. So I created 4 zram devices of
> size 16G. Doing this because I can't find system with 4 free SSD disk
                                                        ~~~~~~~
This description is misleading, testing this patch needs multiple SSD
disks, 2 disks is enough, more is better. Sorry I was dizzy when posting
last night.

> which can be used as swap devices. And nowadays, swap, zram become more
> and more popular, even default setup, so I create zram to test patch.
> # free -h
>                total        used        free      shared  buff/cache   available
> Mem:            62Gi       1.6Gi        61Gi       4.8Mi       276Mi        61Gi
> Swap:           63Gi          0B        63Gi
> 
> 1) create zram
> #My fedora will add one zram0 by default, I reset it because the zram size if not enough
                                                                             ~s/if/is/
> swapoff /dev/zram0 
> 
> cd /sys/block/
> echo 1 > zram0/reset
> cat /sys/class/zram-control/hot_add
> cat /sys/class/zram-control/hot_add
> cat /sys/class/zram-control/hot_add
>  
> echo 16G > zram0/disksize 
> echo 16G > zram1/disksize 
> echo 16G > zram2/disksize
> echo 16G > zram3/disksize 
>  
> mkswap /dev/zram0
> mkswap /dev/zram1
> mkswap /dev/zram2
> mkswap /dev/zram3
>  
> swapon /dev/zram0
> swapon /dev/zram1
> swapon /dev/zram2
> swapon /dev/zram3
> 
> 2) Create memcg with 4G (this avoids noise from other anon process in system)
                                                        ~~~~~~~~~~~
                                      it should be anon mem regions from other process
> cd /sys/fs/cgroup/
> mkdir testing
> echo 4G > testing/memory.max
> echo 3G > testing/memory.high
> 
> 3) Run usemem in memcg
> cgexec -g memory:testing ~/vm-scalability/usemem --init-time -O -y -x -n 31 2G > ~/vm-scalability/temp.txt
> 
> The usemem output is not easy to understand, I will attach my draft
> script in thread for easing result collecting and statistics.
>