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From: "John S. Dyson" <toor@dyson.iquest.net>
Message-Id: <199708231721.MAA11474@dyson.iquest.net>
Subject: Re: Problems with > 256MB of RAM [what worked & what didn't]
In-Reply-To: <Pine.LNX.3.95.970823144610.10666D-100000@unicorn> from Gordon Henderson at "Aug 23, 97 02:46:46 pm"
To: gordon@drogon.net (Gordon Henderson)
Date: Sat, 23 Aug 1997 12:21:50 -0500 (EST)
Cc: hackers@FreeBSD.ORG
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> 
> Tor Egge <Tor.Egge@idi.ntnu.no> suggested:
> > There are two main reasons for this type of panic
> > 
> >         1. temporary shortage of free physical memory (cf PR#2431).
> >
> >            Use sysctl to increase limits of reserved free physical
> >            memory, reducing the probability for running out of free memory.
> > 
> >                 sysctl -w vm.v_free_reserved=1024
> >                 sysctl -w vm.v_free_min=1500
> 
> This worked.
> 
> Tor also suggested:
> >         2. permanent shortage of virtual memory allocated for pv entries.
> >
> >            Increase the size of allocated virtual memory for pv entries
> >            by adding:
> >                
> >                 options         "PMAP_SHPGPERPROC=400"
> 
> This didn't work. Upping it to 800 didn't work either. Same panic at the
> same place.
> 
> John S. Dyson <toor@dyson.iquest.net> suggested changing NKPDE in pmap.h
> (DG's patch bumped this from 63 to 127). I upped it to 255. Didn't work.
> Machine didn't even boot! Stopped at:
> 
You would have terrible problems if you increase NKPDE further without other
changes (like in the Makefile.)  I didn't realize that we had a problem of
running out of free memory causing a pv entry allocation failure.  I'll have
to look at it.

John