Re: pkg upgrade, vfs.zfs.arc.free_target, vfs.zfs.arc.sys_free, vm.pageout_oom_seq

From: Mark Millard <marklmi_at_yahoo.com>
Date: Mon, 01 Sep 2025 00:03:53 UTC 
On Aug 31, 2025, at 12:01, Graham Perrin <grahamperrin@gmail.com> wrote:

> On 31/08/2025 09:38, Mark Millard wrote:
> 
>> …
>> 
>> So 4 GiBytyes of RAM is insufficient, even with use of: vm.pageout_oom_seq=120
>> 
>> Note: In this context increases is not going to help: it is way too little RAM
>> for pkg. (I was observing via top at the time.)
>> 
>> If pkg continues to require such RAM+SWAP usage, FreeBSD is going to end up
>> requiring more than, say, 5 GiBytes of RAM+SWAP, even for UFS contexts.
>> 
>>> …
>> 
>> For reference, see:
>> 
>> https://lists.freebsd.org/archives/freebsd-pkgbase/2025-August/000804.html
>> 
>> with details of my test context (where swap was in use).
> 
> 
> Interesting.
> 
> Here, with faster storage for a new guest, 1,024 MB base memory was enough – for both UFS and ZFS – as outlined below.
> 
> ----
> 
> 
> VirtualBox
> bidirectional shared clipboard
> 1 GB memory
> EFI
> four processors
> PAE/NX
> VBoxSVGA
> FreeBSD-14.3-RELEASE-amd64-dvd1.iso
> disable host I/O cache
> vm.pageout_oom_seq=120
> UFS
> 3 G swap

So you are specifying (RAM+SWAP) being 4 GiBytes, not a 1 GiByte context,
given the memory pattern is that dirty pages are making it to the laundry
instead of staying active.

What sort of (Maximum) Swap Used figures were being reported by
the likes of top?

> install all components
> pkbasify conversion before first boot (519 packages)
> first boot
> vm.pageout_oom_seq=120
> pkg install -Fy firefox gitup htop hw-probe kde lsblk lynx nano pciutils plasma6-sddm-kcm roxterm sddm stressdisk uclcmd usbutils virtualbox-ose-additions xfce xorg
> pkg install -Uy firefox gitup htop hw-probe kde lsblk lynx nano pciutils plasma6-sddm-kcm roxterm sddm stressdisk uclcmd usbutils virtualbox-ose-additions xfce xorg
> pkg upgrade -fFqy
> pkg upgrade -fUy
> 1353 packages
> 2601 steps
> success
> vm.pageout_oom_seq=12
> pkg upgrade -fUy
> success
> 
> ----
> 
> 
> The same with ZFS. Success with, then without, the increased vm.pageout_oom_seq
> 


===
Mark Millard
marklmi at yahoo.com