On Jan 11, 2008 10:57 AM, sahlot arvind <asahlot@xxxxxxxxx> wrote:
yes, thats right.
This means any virtual address can be translated to the physical address by simply subtracting PAGE_OFFSET at 3GB on x86, which is essentially what the function virt_to_phys() with the macro __pa() does.
Hi All,I just started learning Linux Virtual Memory Management Subsystem.I see the memory is divided into three zones. Comments in file mm/mmzone.h/** ZONE_DMA < 16 MB ISA DMA capable memory
* ZONE_NORMAL 16-896 MB direct mapped by the kernel
* ZONE_HIGHMEM > 896 MB only page cache and user processes
*/
Here second comment (ZONE_NORMAL) says that it is directly mapped by kernel.Could anybody please tell me what does direct mean here?Does this mean Physical address = Virtual Address???
yes, thats right.
This means any virtual address can be translated to the physical address by simply subtracting PAGE_OFFSET at 3GB on x86, which is essentially what the function virt_to_phys() with the macro __pa() does.
Thanks- Arvind
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