Re: kern/55166: uvm_pdpolicy_clock params (anon/exec/file max/min) defaults

[Andrew Doran <ad%netbsd.org@localhost>]

On Sun, Apr 12, 2020 at 11:38:14PM +0200, Joerg Sonnenberger wrote:

> On Sat, Apr 11, 2020 at 04:40:00PM +0000, Izumi Tsutsui wrote:
> > There parameters can be changed by sysctl(8), but initial values
> > are hardcorded in uvmpdpol_init():
> 
> What about actually tuning the initial parameters on the amount of RAM
> in the system? That seems much more sensible than hard-coding different
> option sets in various kernels. It's not like it is going to add a lot
> of (cold) code.

Agree, I would prefer to see this keyed off uvmexp.npages since it's not
really architecture specific.

> > Using the following sysctl vm values on dreamcast and x68k
> > makes many applications (including twitter/mastodon clients)
> > work as they can be used as demonstrations at conferences:
> > ---
> > vm.anonmax=30
> > vm.anonmin=10
> > vm.execmax=50
> > vm.execmin=20
> > vm.filemax=1
> > vm.filemin=0
> 
> filemax seems questionable to me, the rest sound a useful default for
> systems with <= 16MB RAM. 

I think filemin=0 could potentially lead to bad behaviour and would prefer
to see it non-zero.

Andrew