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

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

The following reply was made to PR kern/55166; it has been noted by GNATS.

From: Andrew Doran <ad%netbsd.org@localhost>
To: Joerg Sonnenberger <joerg%bec.de@localhost>
Cc: gnats-bugs%netbsd.org@localhost, kern-bug-people%netbsd.org@localhost,
	gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/55166: uvm_pdpolicy_clock params (anon/exec/file max/min)
 defaults
Date: Mon, 13 Apr 2020 15:58:12 +0000

 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