CVS commit: src/sys/arch

["Jason R Thorpe" <thorpej%netbsd.org@localhost>]

Module Name:    src
Committed By:   thorpej
Date:           Thu Apr 30 14:10:04 UTC 2026

Modified Files:
        src/sys/arch/amiga/include: vmparam.h
        src/sys/arch/atari/include: vmparam.h
        src/sys/arch/cesfic/include: vmparam.h
        src/sys/arch/hp300/include: vmparam.h
        src/sys/arch/luna68k/include: vmparam.h
        src/sys/arch/m68k/include: vmparam.h
        src/sys/arch/m68k/m68k: vm_machdep.c
        src/sys/arch/mac68k/include: vmparam.h
        src/sys/arch/mvme68k/include: vmparam.h
        src/sys/arch/news68k/include: vmparam.h
        src/sys/arch/next68k/include: vmparam.h
        src/sys/arch/sun2/include: vmparam.h
        src/sys/arch/sun3/include: vmparam.h
        src/sys/arch/virt68k/include: vmparam.h
        src/sys/arch/x68k/include: vmparam.h

Log Message:
Centralize the definition of VM_PHYS_SIZE.  While doing so, change
the logic for its value, eliminating the obsolete USRIOSIZE constant.

Previously, on Utah-derived platforms, USRIOSIZE was defined as the
number of PTEs used for phys_map, and VM_PHYS_SIZE was USRIOSIZE * PAGE_SIZE.
The USRIOSIZE was in turn derived from NPTEPG (number of PTEs in one page).

On 4K page systems, that was a 4MB phys_map.  On 8K page systems, that
was a 16MB phys_map (4x muliplier comes from 2x PTEs per page, 2x bytes
per page mapped).  These values are totally excessive; the most pressure
phys_map experiences on a typical system is boot-time fsck, and the max
mapping request it will see is MAXPHYS (64KB); it is generally not used in
steady-state operation.  In contrast, alpha's phys_map is 512KB and 32-bit
x86 is ~1MB.

Instead, simply define reasonable values for VM_PHYS_SIZE independent of
PAGE_SIZE: 256KB for 68010, 1MB for everone else.  Per-platform constraints
can override these values (although they happen to match what Sun2 and Sun3
use, respectively).

A compile-time assertion is used to ensure that at least 2 concurrent
physios fit into phys_map.


To generate a diff of this commit:
cvs rdiff -u -r1.53 -r1.54 src/sys/arch/amiga/include/vmparam.h
cvs rdiff -u -r1.40 -r1.41 src/sys/arch/atari/include/vmparam.h
cvs rdiff -u -r1.29 -r1.30 src/sys/arch/cesfic/include/vmparam.h
cvs rdiff -u -r1.49 -r1.50 src/sys/arch/hp300/include/vmparam.h
cvs rdiff -u -r1.33 -r1.34 src/sys/arch/luna68k/include/vmparam.h
cvs rdiff -u -r1.5 -r1.6 src/sys/arch/m68k/include/vmparam.h
cvs rdiff -u -r1.45 -r1.46 src/sys/arch/m68k/m68k/vm_machdep.c
cvs rdiff -u -r1.54 -r1.55 src/sys/arch/mac68k/include/vmparam.h
cvs rdiff -u -r1.48 -r1.49 src/sys/arch/mvme68k/include/vmparam.h
cvs rdiff -u -r1.33 -r1.34 src/sys/arch/news68k/include/vmparam.h
cvs rdiff -u -r1.37 -r1.38 src/sys/arch/next68k/include/vmparam.h
cvs rdiff -u -r1.20 -r1.21 src/sys/arch/sun2/include/vmparam.h
cvs rdiff -u -r1.41 -r1.42 src/sys/arch/sun3/include/vmparam.h
cvs rdiff -u -r1.14 -r1.15 src/sys/arch/virt68k/include/vmparam.h
cvs rdiff -u -r1.48 -r1.49 src/sys/arch/x68k/include/vmparam.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.