Subject: kern/7337: low memory boot panics with uvmexp.swpgonly botch
To: None <>
From: Ignatios Souvatzis <>
List: netbsd-bugs
Date: 04/07/1999 23:25:46
>Number:         7337
>Category:       kern
>Synopsis:       low memory boot panics with uvmexp.swpgonly botch
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Apr  7 14:35:02 1999
>Originator:     Ignatios Souvatzis
>Release:        1999 April 4
System: NetBSD jocelyn 1.4_ALPHA NetBSD 1.4_ALPHA (ISDN7) #13: Wed Apr 7 00:15:13 MEST 1999 is@jocelyn:/build2/i4b/ISDN7 amiga

when (actually, simulating) booting on a 4 MB Amiga, sometime during transition
to multi-user, I get

panic: uvmexp.swpgonly botch

call uvm_dump shows:

Current UVM status:
  pagesize=8192 (0x2000), pagemask=0x1fff, pageshift=13
  214 VM pages: 11 active, 10 inactive, 26 wired, 14 free
  freemin=10, free-target=13, inactive-target=14, wired-max=71
  faults=59564, traps=48092, intrs=104052, ctxswitch=23334
  softint=51810, syscalls=5902, swapins=5, swapouts=10
  fault counts:
    noram=0, noanon=0, pgwait=1344, pgrele=0
    ok relocks(total)=20612(20613), anget(retrys)=18288(11144), amapcopy=1271
    neighbor anon/obj pg=2884/7287, gets(lock/unlock)=40557/9469
    cases: anon=17334, anoncow=952, obj=40373, prcopy=183, przero=720
  daemon and swap counts:
    woke=4418, revs=4247, scans=30490, swout=2545
    busy=1168, freed=24416, reactivate=0, deactivate=46170
    pageouts=2269, pending=2269, nswget=9813
    nswapdev=1, nanon=5194, nfreeanon=4893
    swpages=5000, swpginuse=312, swpgonly=5001 paging=0
  kernel pointers:

I get this even with a GENERIC kernel:

NetBSD 1.4_ALPHA (GENERIC) #33: Wed Apr  7 08:59:47 MEST 1999
DraCo rev.4 (68060 rev.1 CPU/MMU/FPU)
real  mem = 4194304 (512 pages)
avail mem = 1695744 (207 pages)
using 38 buffers containing 311296 bytes of memory
from the bootblocks' prompt: netbsd -m4096 -S


Workaround: use enough memory.