Robert P. J. Day wrote:
following on my previous question, i'm following the tradition of a
few authors and using "logical" kernel address to refer to any address
in the kernel address space that maps to its physical address just
based on a simple offset. that is, given the kernel address space in
the range 3G-4G, a good chunk of the lower part of that range maps to
physical addresses simply by subtracting the offset of 3G
(0xC0000000).
Yes, as long as what you refer doesn't belong to vmalloc area (the
upper 128 MB address space). That area is simply reserved to map high
memory area, fixed mapping and so on.
does this addressing hold for the *entire* NORMAL zone? that is,
does all of ZONE_NORMAL (16M-896M) *always* consist *solely* of
logical addresses, leaving only physical memory above 896M for dynamic
addressing, regardless of much RAM is on the system? thanks.
If I follow your above definition, then yes ZONE_NORMAL only have
logical addres. BTW, may I suggest to use "linear address" term instead?
Logical address, according to UTLK, refer to the address that use
segment and offset.
Also, if I am allowed to rephrase your subject, maybe it is better to
label it "do all physical pages in ZONE_NORMAL only have logical
address?" because what we really refer here is the page while
ZONE_NORMAL denotes physical memory range.
regards,
Mulyadi
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