Re: macppc system wedging under memory pressure

[Mike Pumford <mpumford%mudcovered.org.uk@localhost>]

On 16/09/2022 06:14, Lloyd Parkes wrote:
> You aren't the first person to have problems with memory pressure. We 
> really are going to have to get around to documenting the memory 
> management algorithms and all the tuning knobs.
>
> I used to use this page (https://imil.net/NetBSD/mirror/vm_tune.html), 
> but I have no idea how current it is. Also, I haven't used my smaller 
> systems for a while now.
>
> In the past, I used to set vm.filemax to 5 because I never want a page 
> that I can simply reread to force an anonymous page to be written out to 
> swap.
I've been running my build system ( an 8 core amd64 system with 16GB of 
RAM) with:

vm.filemax=10
vm.filemin=1

So its not just SMALL systems that need better tuning.

Before I set those I found that the system would prioritise file cache 
so much that any large process that ran for a long time would be forced 
to swap out so much that it would then take them ages to recover. In my 
case that was the jenkins process that was managing the build leading to 
lots of failed builds as the jenkins process fell apart. Setting those 
limits meant the file cache got evicted instead of the jenkins process.

I also found the same settings kept things like firefox from getting 
swapped out during builds as well.

This is all on 9.3 stable and all alther vm.xxx setting are at their 
default.

Mike