Date: Fri, 12 Apr 1996 18:00:00 -0400 (EDT) From: Charles Owens <owensc@enc.edu> To: questions list FreeBSD <freebsd-questions@freebsd.org> Subject: unravelling page fault occurances Message-ID: <Pine.FBS.3.92.960412174622.10948F-100000@dingo.enc.edu>
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I understand the basics about the VM system and that a page fault occurs
when the swapper tries to pull in a bit of memory that's been paged out
and can't find it in the swap space. What other subtle stuff can come
into play?
I have a system (2.1-stable, running both NIS and quotas) that works well
most of the time, but from time to time resets, particularily when I'm
creating new uses (I've modified adduser to work with NIS and quotas).
Most of the time I don't get any logging info, but once I've caught a
glimpse of a page fault message on the console and today stuff actually
showed up in the /var/log/messages file.
Here's what I got while adding a user:
Apr 12 10:21:07 itsdsv1 /kernel: Fatal trap 12: page fault while in kernel
mode
Apr 12 10:21:08 itsdsv1 /kernel: fault virtual address = 0x0
Apr 12 10:21:08 itsdsv1 /kernel: fault
And, later, when I tried to create a few more users:
Apr 12 10:40:16 itsdsv1 /kernel: Fatal trap 12: page fault while in kernel mode
Apr 12 10:40:17 itsdsv1 /kernel: fault virtual address = 0x0
Apr 12 10:40:17 itsdsv1 /kernel: fault code = supervisor write, page not present
Apr 12 10:40:17 itsdsv1 /kernel: instruction pointer = 0x8:0xf0180745
Apr 12 10:40:17 itsdsv1 /kernel: code segment = base 0x0, limit 0xfffff, type 0x1b
Apr 12 10:40:17 itsdsv1 /kernel: = DPL 0, pres 1, def32 1, gran 1
Apr 12 10:40:17 itsdsv1 /kernel: processor eflags = interrupt enabled, resume, IOPL = 0
Apr 12 10:40:17 itsdsv1 /kernel: current process = 700 (popper)
Apr 12 10:40:17 itsdsv1 /kernel: interrupt mask =
Apr 12 10:40:17 itsdsv1 /kernel: panic: page fault
Apr 12 10:40:17 itsdsv1 /kernel:
Apr 12 10:40:17 itsdsv1 /kernel: syncing disks...
What should I suspect? The quota system? My SCSI drives? Popper?
FYI, it's a P100 ASUS P55TP4XE (512k PB-cache) system with an Acculogic
SCSI controller (NCR 53c825). I have two SCSI drives:
1 gig SCSI-2: "DEC DSP3105S 392A"
4 gig SCSI-2 WIDE: "SEAGATE ST15230W 0298"
Any direction would be most appreciated. If more info about the system or
system logs would help, just holler...
thanks,
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Charles Owens Email: owensc@enc.edu
"I read somewhere to learn is to
Information Technology Services remember... and I've learned that
Eastern Nazarene College we've all forgot..." - King's X
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