This holds true for phys address 0-896
MB on x86 32 bit
Whereas fix mapped linear address is used for things like vmalloc
mapping, temporary mapping for atomic page mapping and so on
MB on x86 32 bit
Whereas fix mapped linear address is used for things like vmalloc
mapping, temporary mapping for atomic page mapping and so on
That means fix-mapped linear addresses are for managing memory in ZONE_HIGHMEM, while just linear addresses are for managing in ZONE_NORMAL?
In my pc the size of RAM is 256 MB - does that mean there is no ZONE_HIGHMEM available in my system and all the memory is mapped in ZONE_NORMAL and for dynamic (noncontiguous) allocation of pages ZONE_NORMAL is used?
Thanks
On 4/28/08, Mulyadi Santosa <mulyadi.santosa@xxxxxxxxx> wrote:
Let me try....
On Sun, Apr 27, 2008 at 7:56 PM, sahlot arvind <asahlot@xxxxxxxxx> wrote:
> What is the actual difference between Fix-mapped linear addresses and linear
> addresses of kernel mapped in the first part of 4th GB of memory?
Addresses starting from the 4th GB are used for identical mapping...
that is 1 to 1 relationship. Thus, for page at physical address n, it
has a mapping at n+PAGE_OFFSET. This holds true for phys address 0-896
MB on x86 32 bit
Whereas fix mapped linear address is used for things like vmalloc
mapping, temporary mapping for atomic page mapping and so on. IMHO it
is said "fix" because it stays on certain predefined range....that is
the upper 128 MB of the 4th GB address space. Again, this is for x86
32 bit.
regards,
Mulyadi.
--
http://linuxexplained.blogspot.com
