On Sat, 5 Dec 1998 01:13:11 -0800 (PST) 
 Jonathan Stone <jonathan@netbsd.org> wrote:

 > Module Name:	src
 > Committed By:	jonathan
 > Date:		Sat Dec  5 09:13:10 UTC 1998
 > 
 > Modified Files:
 > 	src/sys/arch/mips/mips: pmap.c
 > Log Message:
 > Track PV_REFERENCED bit as for PV_MODIFIED,  to make mdsetimage work correctly.
 > Compatiblity with Mach VM: clear pmap-private bits in pmap_remove() if !UVM.

That latter bit is WRONG.  For example, the hp300 pmap SPECIFICALLY remembers
the ref/mod bits from the PTE in the pmap_attributes entry for that page
when a mapping is removed.

"referenced" and "modifed" are attributes of the hardware page, not the
mapping of it.  Consider if a page is double-mapped.  With your change,
you have now broken mod/ref tracking for double-mapped pages when one
of the mappings is removed.

Jason R. Thorpe                                       thorpej@nas.nasa.gov
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