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correct and clarify the previous revision.

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chs 2002-04-01 17:30:02 +00:00
parent af2aedbe22
commit 272a0d7448
1 changed files with 11 additions and 13 deletions
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24
share/man/man9/pmap.9
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@ -1,4 +1,4 @@
.\" $NetBSD: pmap.9,v 1.13 2002/03/28 18:22:20 eeh Exp $
.\" $NetBSD: pmap.9,v 1.14 2002/04/01 17:30:02 chs Exp $
.\"
.\" Copyright (c) 2000, 2001 The NetBSD Foundation, Inc.
.\" All rights reserved.
@ -308,19 +308,17 @@ be cleared is when the virtual memory system explicitly calls the
.Fn pmap_clear_modify
and
.Fn pmap_clear_reference
functions. These functions also need to do whatever is necessary
to restart the collection of state information for that page,
including possibly calling
.Fn pmap_page_protect
if the
functions. These functions must also change any internal state
necessary to detect the page being modified or referenced again
after the modified or referenced state is cleared. (Prior to NetBSD 1.6,
.Nm
is doing modified/referenced emulation.
.\"
.\" Resetting ref/mod gathering inside of pmap_clear_modify() and
.\" pmap_clear_reference began with UBC. Pre-UBC UVM required the
.\" opposite behavior or it would discover it modified a page trying
.\" to write it out and get very confused.
.\"
implementations could get away without this because UVM (and Mach VM
before that) always called
.Fn pmap_page_protect
before clearing the modified or referenced state, but UVM has been changed
to not do this anymore, so all
.Nm
implementations must now handle this.)
.Ss STATISTICS
The
.Nm