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Date: Sat, 23 Aug 1997 14:46:46 +0100 (BST)
From: Gordon Henderson <gordon@drogon.net>
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To: hackers@freeBSD.org
Subject: Re: Problems with > 256MB of RAM [what worked & what didn't]
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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:

  Boot:
  dosdev= 80, biosdrive = 0, unit = 0, maj = 0
  Booting 0:wd(0,a)/kernel @ 0x100000
  text=0x8f000 data=0xc000 bss=0xd484 symbols=[+0xb7c+0x4+0xc378+0x4+0x10169]
  total=0x1c54e9 entry point=0x100000

Needed a hardware reset.

So, I've stuck Tor's sysctls in my /etc/rc.local for now and all seems
well. If anyone wants to add to this, feel free and I'll check it if I
have time.

Gordon