11.2-STABLE kernel wired memory leak

[Eugene Grosbein]

20.02.2019 3:49, Mike Tancsa wrote:

> On 2/19/2019 2:35 PM, Mike Tancsa wrote:
>> dd if=/dev/zero of=/tanker/test bs=1m count=100000
> 
> The box has 32G of RAM. If I do a
> 
> # sysctl -w vfs.zfs.arc_max=12224866304
> vfs.zfs.arc_max: 32224866304 -> 12224866304
> #
> 
> after WIRED memory is at 29G, it doesnt immediately reclaim it and there
> is memory pressure.  Booting the box with
> vfs.zfs.arc_max=12224866304
> keeps WIRED at 15G

Can you repeat your test with additional vm.v_free_min=131072 (512M) or 262144 (1G)?
For me, it makes kernel reclaim unused UMA memory quickly:
first it goes from WIREE to FREE for a moment, then re-used as needed.