> I would like to know for any particular kernel version where in
> the kernel header files the virtual memory addressability is
> defined. Rubini's book suggests that user addresses are in the
> 0-3GB range and that the kernel resides higher than that. I'd
> like to make sure that this is not something that is changing.
On the i386, the actual location depends on (a) how much physical RAM
is in the system in question, and (b) the setting of the following
configuration option (found in arch/i386/config.in for those curious):
Q> choice 'Maximum Physical Memory' \
Q> "1GB CONFIG_1GB \
Q> 2GB CONFIG_2GB" 1GB
If that option is set to its default, then the kernel (and physical
RAM) lives between 3-4G, but if it's set to its 2GB setting, they live
between 2-4G. Either way, user memory lies between 0 and the low end
of the selected range.
Note that there have been rumours of problems on systems with >960M of
RAM where the kernel is compiled for 1GB. I can't verify any problems
as I don't have access to any systems with that much RAM, but I also
can't state what the problems are as the reports I have seen just left
me more confused than before I read them.
Best wishes from Riley.
+----------------------------------------------------------------------+
| There is something frustrating about the quality and speed of Linux |
| development, ie., the quality is too high and the speed is too high, |
| in other words, I can implement this XXXX feature, but I bet someone |
| else has already done so and is just about to release their patch. |
+----------------------------------------------------------------------+
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/