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| -rw-r--r-- | share/man/man4/man4.i386/Makefile | 2 | ||||
| -rw-r--r-- | share/man/man4/man4.i386/pae.4 | 125 |
2 files changed, 126 insertions, 1 deletions
diff --git a/share/man/man4/man4.i386/Makefile b/share/man/man4/man4.i386/Makefile index 59714e3..42ae6c9 100644 --- a/share/man/man4/man4.i386/Makefile +++ b/share/man/man4/man4.i386/Makefile @@ -5,7 +5,7 @@ MAN= aic.4 alpm.4 amdpm.4 apm.4 ar.4 asc.4 asr.4 \ dgb.4 el.4 en.4 ep.4 ex.4 fe.4 gsc.4 \ ie.4 io.4 le.4 linux.4 lnc.4 longrun.4 mcd.4 \ meteor.4 mse.4 npx.4 \ - pcf.4 perfmon.4 pnp.4 pnpbios.4 \ + pae.4 pcf.4 perfmon.4 pnp.4 pnpbios.4 \ ray.4 rdp.4 smapi.4 scd.4 \ spkr.4 sr.4 streams.4 svr4.4 tw.4 \ tx.4 viapm.4 vpd.4 vx.4 \ diff --git a/share/man/man4/man4.i386/pae.4 b/share/man/man4/man4.i386/pae.4 new file mode 100644 index 0000000..2f063f6 --- /dev/null +++ b/share/man/man4/man4.i386/pae.4 @@ -0,0 +1,125 @@ +.\" +.\" Copyright (c) 2003 Networks Associates Technology, Inc. +.\" All rights reserved. +.\" +.\" This software was developed for the FreeBSD Project by Jake Burkholder, +.\" Safeport Network Services, and Network Associates Laboratories, the +.\" Security Research Division of Network Associates, Inc. under +.\" DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA +.\" CHATS research program. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd April 8, 2003 +.Dt PAE 4 i386 +.Os +.Sh NAME +.Nm PAE +.Sh SYNOPSIS +.Cd options PAE +.Sh DESCRIPTION +The +.Nm +option provides support for the physical address extensions capability +of the +.Tn Intel +.Tn Pentium Pro +and above CPUs, +and allows for up to 64 gigabytes of memory to be used in systems capable +of supporting it. +With the +.Nm +option, memory above 4 gigabytes is simply added to the general page pool. +The system makes no distinction between memory above or below 4 gigabytes, +and no specific facility is provided for a process or the kernel to access +more memory than they would otherwise be able to access, through a sliding +window or otherwise. +.Sh SEE ALSO +.Xr smp 4 +.Xr tuning 7 +.Xr config 8 +.Sh HISTORY +The +.Nm +option first appeared in +.Fx 5.1 . +.Sh AUTHORS +.An Jake Burkholder Aq jake@FreeBSD.org +.Sh BUGS +Since kld modules are not compiled with the same options headers that +the kernel is compiled with, +they must not be loaded into a kernel compiled with the +.Nm +option. +.Pp +Many devices or their device drivers are not capable of direct memory access +to physical addresses above 4 gigabytes. +In order to make use of direct memory access IO in a system with more than +4 gigabytes of memory when the +.Nm +option is used, +these drivers must use a facility for remapping or substituting physical +memory which is not accessible to the device. +One such facility is provided by the +.Nm busdma +interface. +Device drivers which do not make affordances for such devices will not work +reliably in a system with more than 4 gigabytes of memory when the +.Nm +option is used, +and may cause data corruption. +The +.Nm +kernel configuration file includes the +.Nm +option, and explicitly excludes all device drivers which are known to not work +or have not been tested in a system with the +.Nm +option and more than 4 gigabytes of memory. +.Pp +Many parameters which determine how memory is used in the kernel are based on +the amount of physical memory. +The formulas used to determine the values of these paramters for specific +memory configurations may not take into account the fact there may be more +than 4 gigabytes of memory, and may not scale well to these memory +configurations. +In particular, +it may be necessary to increase the amount of virtual address space available +to the kernel, +or to reduce the amount of a specific resource that is heavily used, +in order to avoid running out of virtual address space. +The +.Nm KVA_PAGES +option may be used to increase the kernel virtual address space, +and the +.Nm kern.maxvnodes +sysctl may be used to decrease the number of vnodes allowed, +an example of a resource that the kernel is likely to overallocate in +large memory configurations. +For optimal performance and stability it may be necessary to consult the +.Xr tuning 7 +manual page, and make adjustments to the parameters documented there. +.Pp +Do not taunt Happy Fun +.Nm . |
