Subject: README: this is the change I warned you about
To: None <port-amiga@netbsd.org, port-atari@netbsd.org>
From: Jason Thorpe <thorpej@nas.nasa.gov>
List: port-atari
Date: 06/16/1999 14:12:40
This is that UVM change that I warned you about yesterday.
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Module Name: syssrc
Committed By: thorpej
Date: Wed Jun 16 19:34:25 UTC 1999
Modified Files:
syssrc/sys/uvm: uvm_map.c
Log Message:
Modify uvm_map_pageable() and uvm_map_pageable_all() to follow POSIX 1003.1b
semantics. That is, regardless of the number of mlock/mlockall calls,
an munlock/munlockall actually unlocks the region (i.e. sets wiring count
to 0).
Add a comment describing why uvm_map_pageable() should not be used for
transient page wirings (e.g. for physio) -- note, it's currently only
(ab)used in this way by a few pieces of code which are known to be
broken, i.e. the Amiga and Atari pmaps, and i386 and pc532 if PMAP_NEW is
not used. The i386 GDT code uses uvm_map_pageable(), but in a safe
way, and could be trivially converted to use uvm_fault_wire() instead.
To generate a diff of this commit:
cvs rdiff -r1.55 -r1.56 syssrc/sys/uvm/uvm_map.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
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-- Jason R. Thorpe <thorpej@nas.nasa.gov>