> We're testing some x86 systems with more than 1GB of RAM. Linux on
> x86 seems to be limited to 1GB of physical memory. This suprised me
> a bit since I thought 386 PTE's had 20 bits for physical page
> addresses (4GB physical). Is there a 1GB physical limit, what's the
> reason for the limit, and what would need to change to increase this
> to 4GB? (i.e. Where did those other 2 bits go?)
Linus told me the (effective?) limit is actually lower than 1GB for
possibly different reasons than the ones you mention (allocation of
kernel-space memory vs. user-space memory?), maybe 768 MB.
Basically, he said that some settings need to be changed, but it
sounded like a minor change.
-- Daniel Quinlan (at work) Linux, our last best hope for Unix quinlan@transmeta.com http://www.pathname.com/~quinlan/