Re: ZFS high CPU use after backup and panic on shutdown

Trev wrote on 28/11/23 12:09 am:
> Trev wrote on 25/11/23 2:39 pm:
>> I recently updated from source FreeBSD 12-STABLE to FreeBSD 13-STABLE 
>> (stable/13-221a60a42: Tue Nov 14 15:36:40 AEDT 2023).
>>
>> Ever since, after my ZFS backup to an external USB drive, the system 
>> continues to consume 100% of one core of the 2011 Mac mini (i7, 16G).
>>
>> Example backup command from my shell script:
>>
>> zfs send data/www@${snapshot} | bzip2 > /mnt/zfs-data-www-${snapshot}.bz2
>>
>> Neither top, vmstat nor iostat give any clue as to what system process 
>> is using 100% of one core. To stop this phenomenon I have to shutdown 
>> and reboot the system which I do with "shutdown -r now".
>>
>> This always results in a kernel panic:
> 
> [CHOMP]
> 
> Resolved by updating the source to stable/13-ecb4d2c6e: Sat Nov 25 
> 11:31:12 AEDT 2023 and rebuilding.
> 
> [Also, thanks to Mike Karels for off-list help with top.]

ARGH. After a few days the issue has again returned. top -S -H shows 
that the process which continues to consume 100% of one CPU core is 
arc_prune, the same process that causes a kernel panic on shutdown.

Any ideas on how to resolve this?