Re: zfs pool behavior - is it ever freed?

[Greg Troxel <gdt%lexort.com@localhost>]

tlaronde%polynum.com@localhost writes:

> On Sat, Jul 29, 2023 at 12:42:13PM +0200, Tobias Nygren wrote:
>> On Fri, 28 Jul 2023 20:04:56 -0400
>> Greg Troxel <gdt%lexort.com@localhost> wrote:
>> 
>> > The upstream code tries to find a min/target/max under the assumption
>> > that there is a mechanism to free memory under pressure -- which there
>> > is not.
>> 
>> There exists ZFS code which hooks into UVM to drain memory -- but part
>> of it is ifdef __i386 for some reason. See arc_kmem_reap_now().
>
> FWIW, with jemalloc, there is the possibility to configure to give back
> memory to the system.
>
> Since jemalloc is incorporated in NetBSD, one(TM) should perhaps look if
> the feature is available and what has to be done in this area to use
> it.

It's unlikely reasonable to rototill the way zfs allocates memory.  The
issue is just that things aren't hooked up.