Subject: Re: vm_fault in pmap_changebit()
To: Chuck Cranor <chuck@maria.wustl.edu>
From: Dave Huang <khym@bga.com>
List: port-i386
Date: 11/13/1997 05:54:10
On Tue, 11 Nov 1997, Chuck Cranor wrote:
> so, the problem is that either the page table page that was mapping
> that address went away when it should not have, or the <PMAP,VA>
> entry on the pv list is a stale one that shouldn't have been there
> in the first place.   note that the page table pages are currently
> part of the user's address space (from VM_MAXUSER_ADDRESS to
> VM_MAX_ADDRESS) and there is an interesting hack to "pre-fault"
> them in in trap.c.   this could be kind of painful to debug.

Thanks for the explanation :) Ah well... I don't know enough to debug this
problem... Might it be somehow related to the "lockmgr: locking against
myself" panics? I haven't been getting those anymore, but I'm now getting
these vm_faults.

> the somewhat good news is that i've re-written the i386 pmap from
> scratch based on the current pmap, with various changes from myself,
> mach, and freebsd thrown in.   i've been using this pmap for a couple
> of months without any problems.  it is possible that it might solve your
> problem.  the somewhat bad news is that my pmap re-write is designed
> to fit in my VM system rather than the Mach based VM system currently in
> the tree.

Cool... are there are there any plans to replace the current VM system
with yours?

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