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

[Baoquan He <bhe@redhat.com>]

On 09/27/25 at 12:02am, Baoquan He wrote:
> 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
> > 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
> > 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)
> > 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.
> 
> 1)
> Yon can fetch usemem from here:
> https://kernel.googlesource.com/pub/scm/linux/kernel/git/wfg/vm-scalability
> 
> 2) In attachments, usemem-calc.sh is used to analyze raw data from
> usemem output, then output an unstandable result. You can copy below
                                ~~ understandable, sorry, typo
> commands to run ten times or how many times you want on usemem.
> 
> for i in {1..10}; do
>     cgexec -g memory:testing ~/vm-scalability/usemem --init-time -O -y -x -n 31 2G > ~/vm-scalability/temp.txt
>     ~/usemem-calc.sh ~/vm-scalability/temp.txt
>     echo "The $i""th time to run usemem" 
> done
> 
> 3) Please keep all the output of usemem-calc.sh to a file, then use
> result.sh to get an average value.
> 
> Any unclear part, please feel free to ask me privately or publicly in
> thread.
> 
> Thanks
> Baoquan