Re: ext2/zram issue [was: Linux 5.19]

From: Jiri Slaby
Date: Tue Aug 09 2022 - 04:13:01 EST


On 09. 08. 22, 9:59, Jiri Slaby wrote:
Ah, now I can. It's easy when one lowers memory available to qemu. -m 800M in this case:
echo $((1000*1024*1024)) > /sys/block/zram0/disksize
mkfs.ext2 /dev/zram0
mount /dev/zram0 /mnt/a/
dd if=/dev/urandom of=/mnt/a/stuff
[  200.334277][    T8] EXT4-fs warning (device zram0): ext4_end_bio:343: I/O error 10 writing to inode 12 starting block 8192)
[  200.340198][    T8] Buffer I/O error on device zram0, logical block 8192


So currently, I blame:
commit e7be8d1dd983156bbdd22c0319b71119a8fbb697
Author: Alexey Romanov <avromanov@xxxxxxxxxxxxxx>
Date:   Thu May 12 20:23:07 2022 -0700

    zram: remove double compression logic


/me needs to confirm.

With that commit reverted, I see no more I/O errors, only oom-killer messages (which is OK IMO, provided I write 1G of urandom on a machine w/ 800M of RAM):
[ 30.424603][ T728] dd invoked oom-killer: gfp_mask=0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), order=0, oom_score_adj=0

Now let me submit it to openQA too...

thanks,
--
js
suse labs